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Sample records for solid tl detectors

  1. Dosimetric characteristics of LKB:Cu,P solid TL detector

    International Nuclear Information System (INIS)

    Hashim, S.; Alajerami, Y.S.M.; Ghoshal, S.K.; Saleh, M.A.; Saripan, M.I.; Kadir, A.B.A.; Bradley, D.A.; Alzimami, K.

    2014-01-01

    The dosimetric characteristics of newly developed borate glass dosimeter modified with lithium and potassium carbonate (LKB) and co-doped with CuO and NH 4 H 2 PO 4 are reported. Broad peaks in the absence of any sharp peak confirms the amorphous nature of the prepared glass. A simple glow curve of Cu doped sample is observed with a single prominent peak (T m ) at 220 °C. The TL intensity response shows an enhancement of ∼100 times due to the addition of CuO (0.1 mol%) to LKB compound. A further enhancement of the intensity by a factor of 3 from the addition of 0.25 mol% NH 4 H 2 PO 4 as a co-dopant impurity is attributed to the creation of extra electron traps with consequent increase in energy transfer of radiation recombination centers. The TL yield performance of LKB:Cu,P with Z eff ≈8.92 is approximately seventeen times less sensitive compared to LiF:Mg,Ti (TLD-100). The proposed dosimeter shows good linearity up to 10 3 Gy, minimal fading and photon energy independence. These attractive features offered by our dosimeter is expected to pave the way towards dosimetric applications. - Highlights: • The NH 4 H 2 PO 4 impurities are cross linked with the CuO defect. • The addition of NH 4 H 2 PO 4 as a co-dopant improved the TL intensity by a factor of 3. • The proposed dosimeter shows good linearity up to 10 3 Gy. • Minimal fading and photon energy independence were observed

  2. Dosimetric characteristics of Li2B4O7:Cu,Ag,P solid TL detectors

    International Nuclear Information System (INIS)

    Proki, M.

    2002-01-01

    The main dosimetric characteristics are presented of newly prepared tissue-equivalent, highly sensitive thermoluminescent detector, Li 2 B 4 O 7 :Cu,Ag,P in the form of sintered pellets, developed at the Institute of Nuclear Sciences, Vin a . As a result of an advancement in the preparation procedure by the sensitising of basic copper activated lithium borate TL material, significant improvement in the TL sensitivity of Li 2 B 4 O 7 :Cu,Ag,P was gained. The glow curve of Li 2 B 4 O 7 :Cu,Ag,P consists of well defined main dosimetric peak situated at about 185-190 deg. C with the TL sensitivity which is about four to five times higher than that of LiF:Mg,Ti (TLD-100). From the experimental results a very wide linear dose response range, up to 10 3 Gy is evident. Dosimetric characteristics make sintered solid Li 2 B 4 O 7 :Cu,Ag,P TL detectors very promising for different dosimetry applications particularly in medical dosimetry and also for individual monitoring. (author)

  3. Electrochemically produced alumina as TL detector

    International Nuclear Information System (INIS)

    Osvay, M.

    1996-01-01

    The goal of this work was to compare the TL properties of various electrochemically produced alumina layers (E-AIO) in order to investigate the effect of the electrolyte and the Mg content on the alloys. It has been found that the TL sensitivity of oxidised layers is more influenced by the type of electrolyte, than by the composition of alloy. Hard oxide layer evolved in reduction electrolyte has rather different character compared to other alumina production investigated. The effect of reducing media seems to be very important during preparation of alumina layer. One of the advantages properties of E-AIO is, that it serve a promising method to increase the measuring range of TL method above 10 kGy as well. (author)

  4. Solid state detector design

    International Nuclear Information System (INIS)

    Gunarwan Prayitno; Ahmad Rifai

    2010-01-01

    Much has been charged particle detector radiation detector made by the industry, especially those engaged in the development of detection equipment and components. The development and further research will be made solid state detector with silicon material. To be able to detect charged particles (radiation), required the processing of silicon material into the detector material. The method used to make silicon detector material is a lithium evaporations. Having formed an intrinsic region contactor installation process, and with testing. (author)

  5. Design and performance of a modularized NaI(Tl) detector (the crystal ball prototype)

    International Nuclear Information System (INIS)

    Chan, Y.; Partridge, R.A.; Peck, C.W.

    1977-01-01

    A prototype NaI(Tl) detector (the Cluster of 54) of spherical geometry subtending a solid angle of 7.5 percent of 4π at its center, has recently been assembled and tested. This detector consisted of 54 close-packed but optically isolated NaI(Tl) modules and the associated electronic circuitry. The Cluster of 54 is the predecessor of an almost complete spherical detector, the Crystal Ball, which will cover 94 percent of 4π. The latter detector is now under construction and is especially designed for the study of γ-rays produced in electron-positron collisions at colliding beam facilities. The mechanical, optical, and electronic assembly of the prototype system is outlined. Cluster of 54 test data will be presented

  6. Solid state track detectors

    International Nuclear Information System (INIS)

    Reuther, H.

    1976-11-01

    This paper gives a survey of the present state of the development and the application of solid state track detectors. The fundamentals of the physical and chemical processes of the track formation and development are explained, the different detector materials and their registration characteristics are mentioned, the possibilities of the experimental practice and the most variable applications are discussed. (author)

  7. Silicon drift detectors coupled to CsI(Tl) scintillators for spaceborne gamma-ray detectors

    International Nuclear Information System (INIS)

    Marisaldi, M.; Fiorini, C.; Labanti, C.; Longoni, A.; Perotti, F.; Rossi, E.; Soltau, H.

    2006-01-01

    Silicon Drift Detectors (SDDs), thanks to their peculiar low noise characteristics, have proven to be excellent photodetectors for CsI(Tl) scintillation light detection. Two basic detector configurations have been developed: either a single SDD or a monolithic array of SDDs coupled to a single CsI(Tl) crystal. A 16 independent detectors prototype is under construction, designed to work in conjunction with the MEGA Compton telescope prototype under development at MPE, Garching, Germany. A single SDD coupled to a CsI(Tl) crystal has also been tested as a monolithic detector with an extended energy range between 1.5 keV and 1 MeV. The SDD is used as a direct X-ray detector for low energy photons interacting in silicon and as a scintillation light photodetector for photons interacting in the crystal. The type of interaction is identified by means of pulse shape discrimination technique. Detectors based on an array of SDDs coupled to a single CsI(Tl) crystal have also been built. The readout of these detectors is based on the Anger camera technique, and submillimeter spatial resolution can be achieved. The two detectors' approaches and their applications will be described

  8. Pulse shaper for scintillation detectors with NaI(Tl) or CsI(Tl) crystals

    International Nuclear Information System (INIS)

    Novisov, B.S.; Maksimenko, A.S.; Baryshev, A.V.; Zhukov, A.V.

    1978-01-01

    The basic circuit of a signal shaper for scintillation detectors with NaI(Tl) and CsI(Tl) crystals is described. To increase amplitude resolution, it is suggested to integrate not the whole charge at the photomultiplier output, but a part of the charge during the initial 100 ns of the current pulse; the remaining part of the current signal is compensated directly at the photomultiplier anode by means of an electric circuit. The principal elements of the spectrometric signal shaper include an input transistor amplifier, a compensation circuit, a key element, a shaper amplifier of time pulses, a shaper of signal duration for controlling the key element, and an output spectrometric amplifier. This device, being used, one can shape pulses at durations of 100 ns and more. The shaper restoration time does not exceed 50 ns. When the shaper operates with NaI(Tl) crystals and at counting rate of 10 6 pulse/s, the amplitude resolution with and without the compensation circuit is 17% and 21% respectively

  9. Solid state detector module

    International Nuclear Information System (INIS)

    Hoffman, D. M.

    1985-01-01

    A solid state detector in which each scintillator is optimally configured and coupled with its associated sensing diode in a way which exploits light piping effects to enhance efficiency, and at the same time provide a detector which is modular in nature. To achieve light piping, the scintillator crystal is oriented such that its sides conform with the crystal cleavage plane, and the sides are highly polished. An array of tungsten collimator plates define the individual channels. Multi-channel scintillator/diode modules are mounted behind and in registry with the plurality of collimator plates. A plurality of scintillators are bonded together after coating the surfaces thereof to minimize optical crosstalk. After lapping the face of the scintillator module, it is then bonded to a diode module with individual scintillators in registration with individual diodes. The module is then positioned in the detector array with collimator plates at the junctions between the scintillators

  10. Experimental study on the CsI (Tl) crystal anti-compton detector in CDEX

    International Nuclear Information System (INIS)

    Liu Shukui; Yue Qian; Tang Changjian

    2012-01-01

    CDEX (China Dark matter Experiment) Collaboration will carry out direct search for dark matter with Ultra-Low Energy Threshold High Purity germanium (ULE-HPGe) detector at CJPL (China Jinping deep underground Laboratory). Before underground research, some experiments of the CsI (Tl) crystal Anti-Compton detector have been done on the ground, including light guide choice, wrapping material choice, height uniformity of CsI (Tl) crystal, side uniformity of CsI (Tl) crystal and the test results of all the crystals. Through the preliminary work on the ground, we have got some knowledge of the anti-compton detector and prepared for the underground experiment. (authors)

  11. Study on effects of gamma-ray irradiation on TlBr semiconductor detectors

    International Nuclear Information System (INIS)

    Matsumura, Motohiro; Watanabe, Kenichi; Yamazaki, Atsushi; Uritani, Akira; Kimura, Norihisa; Nagano, Nobumichi; Hitomi, Keitaro

    2016-01-01

    Radiation hardness of thallium bromide (TlBr) semiconductor detectors to 60 Co gamma-ray irradiation was evaluated. The energy spectra and μτ products of electrons were measured to evaluate the irradiation effects. No significant degradation of spectroscopic performance of the TlBr detector for 137 Cs gamma-rays was observed up to 45 kGy irradiation. Although the μτ products of electrons in the TlBr detector slightly decreased, position of the photo-peak was stable without significant degradation after the gamma-ray irradiation. We confirmed that the TlBr semiconductor detector has a high tolerance for gamma-ray irradiation at least up to 45 kGy. (author)

  12. CsI(Tl)-photodiode detectors for gamma-ray spectroscopy

    CERN Document Server

    Fioretto, E; Viesti, G; Cinausero, M; Zuin, L; Fabris, D; Lunardon, M; Nebbia, G; Prete, G

    2000-01-01

    We report on the performances of CsI(Tl)-photodiode detectors for gamma-ray spectroscopy applications. Light output yield and energy resolution have been measured for different crystals and read-out configurations.

  13. Response function study of a scintillator detector of NaI(Tl); Estudo da funcao resposta de um detector cintilador de NaI(Tl)

    Energy Technology Data Exchange (ETDEWEB)

    Villa, Marcelo Barros; Costa, Alessandro Martins da, E-mail: amcosta@usp.br [Universidade de Sao Paulo (FFCLRP/USP), Ribeirao Preto, SP (Brazil). Faculdade de Filosofia, Ciencias e Letras. Dept. de Fisica

    2014-07-01

    In measurements of gamma rays with Nai (Tl) scintillator, the detectors output data are pulse height spectra, that corresponding to distorted information about the radiation source due to various errors associated with the crystal scintillation process and electronics associated, instead of power spectra photons. Pulse height spectra are related to the real power spectra by means of scintillator detector response function NaI (Tl). In this work, the response function for a cylindrical crystal of Nal (Tl) of 7,62 x 7,62 cm (diameter x length) was studied, by Monte Carlo method, using the EGSnrc tool to model the transport of radiation, combined with experimental measurements. An inverse response matrix, even with the energy of the square root, which transforms the pulse height spectrum of photon energy spectrum was obtained. The results of this transformation of pulse height spectrum for photon energy spectrum is presented, showing that the methodology employed in this study is suitable.

  14. Solid solutions of thallium in TlGaSe2, TlGaS2, and TlInS2

    International Nuclear Information System (INIS)

    Voroshilov, Yu. V.; Potorii, M.V.; Shevchenko, S.V.

    1986-01-01

    The authors study the nature of the dissolution of thallium in ternary phases. They have synthesized alloys of the stoichiometric compositions TlGaS 2 , TlGaSe 2 , and T1InS 2 , and their solid solutions, maximally enriched in thallium, the compositions of which were Tl /SUB 1.34/ GA /SUB 0.89/ S 2 , Tl /SUB 1.31/ Ga /SUB 0.90/ Se 2 , and Tl /SUB 1.15/ In /SUB 0.95/ S /SUB 2./ . Samples were synthesized from the elemental components of the following purities: gallium of V4 grade; indium of V4 grade; thallium of T1000 grade; selenium of special purity 22-4 grade, and sulfur of special purity garde. The compositions were checked by x-ray-phase-(DRON-0.5) and microstructural-analyses with simultaneous determination of the density and microhardness of the samples. It is found that the lattic parameter increases and the increase in the density and microhardness points to strengthening of the structure during the formation of the solid solutions

  15. SoLid Detector Technology

    Science.gov (United States)

    Labare, Mathieu

    2017-09-01

    SoLid is a reactor anti-neutrino experiment where a novel detector is deployed at a minimum distance of 5.5 m from a nuclear reactor core. The purpose of the experiment is three-fold: to search for neutrino oscillations at a very short baseline; to measure the pure 235U neutrino energy spectrum; and to demonstrate the feasibility of neutrino detectors for reactor monitoring. This report presents the unique features of the SoLid detector technology. The technology has been optimised for a high background environment resulting from low overburden and the vicinity of a nuclear reactor. The versatility of the detector technology is demonstrated with a 288 kg detector prototype which was deployed at the BR2 nuclear reactor in 2015. The data presented includes both reactor on, reactor off and calibration measurements. The measurement results are compared with Monte Carlo simulations. The 1.6t SoLid detector is currently under construction, with an optimised design and upgraded material technology to enhance the detector capabilities. Its deployement on site is planned for the begin of 2017 and offers the prospect to resolve the reactor anomaly within about two years.

  16. X-ray photoemission analysis of chemically modified TlBr surfaces for improved radiation detectors

    International Nuclear Information System (INIS)

    Nelson, A. J.; Voss, L. F.; Beck, P. R.; Graff, R. T.; Conway, A. M.; Nikolic, R. J.; Payne, S. A.; Lee, J.-S.; Kim, H.; Cirignano, L.; Shah, K.

    2013-01-01

    We subjected device-grade TlBr to various chemical treatments used in room temperature radiation detector fabrication to determine the resulting surface composition and electronic structure. As-polished TlBr was treated separately with HCl, SOCl 2 , Br:MeOH and HF solutions. High-resolution photoemission measurements on the valence band electronic structure and Tl 4f, Br 3d, Cl 2p and S 2p core lines were used to evaluate surface chemistry and shallow heterojunction formation. Surface chemistry and valence band electronic structure were correlated with the goal of optimizing the long-term stability and radiation response

  17. Solid state nuclear track detectors

    International Nuclear Information System (INIS)

    Medeiros, J.A.; Carvalho, M.L.C.P. de

    1992-12-01

    Solid state nuclear track detectors (SSNTD) are dielectric materials, crystalline or vitreous, which registers tracks of charged nuclear particles, like alpha particles or fission fragments. Chemical etching of the detectors origin tracks that are visible at the optical microscope: track etching rate is higher along the latent track, where damage due to the charged particle increase the chemical potential, and etching rate giving rise to holes, the etched tracks. Fundamental principles are presented as well as some ideas of main applications. (author)

  18. On the study of the solid-solid phase transformation of TlBiTe2

    International Nuclear Information System (INIS)

    Chrissafis, K.; Vinga, E.S.; Paraskevopoulos, K.M.; Polychroniadis, E.K.

    2003-01-01

    The narrow gap semiconductor TlBiTe 2 undergoes a solid-solid phase transformation from the rhombohedral (D 3d ) to the cubic (O h ) phase. The present paper deals with the study of this phase transformation combining the results of Differential Scanning Calorimetry (DSC) and Transmission Electron Microscopy (TEM). It has been found that during heating the transformation is an athermal activated process, which can be described only by a combination of more than one processes while during cooling it exhibits an expectable thermal hysteresis due to the volume difference. The results of the kinetic analysis combined with the electron microscopy findings, supported also by the Fourier Transform Infrared (FTIR) spectroscopy ones, lead to the conclusion that TlBiTe 2 undergoes a multiple-step, displacive, martensitic type transformation. (Abstract Copyright [2003], Wiley Periodicals, Inc.)

  19. Solid state radiation detector system

    International Nuclear Information System (INIS)

    1977-01-01

    A solid state radiation flux detector system utilizes a detector element, consisting of a bar of semiconductor having electrical conductance of magnitude dependent upon the magnitude of photon and charged particle flux impinging thereon, and negative feedback circuitry for adjusting the current flow through a light emitting diode to facilitate the addition of optical flux, having a magnitude decreasing in proportion to any increase in the magnitude of radiation (e.g. x-ray) flux incident upon the detector element, whereby the conductance of the detector element is maintained essentially constant. The light emitting diode also illuminates a photodiode to generate a detector output having a stable, highly linear response with time and incident radiation flux changes

  20. Performance of a high-resolution CsI(Tl)-PIN readout detector

    International Nuclear Information System (INIS)

    Kudenko, Yu.G.; Imazato, J.

    1992-10-01

    A study of a large-volume CsI(Tl) detector with a PIN diode readout was carried out. Our results show a light output of ≤20000 photoelectrons/MeV, an equivalent noise charge (rms) of about 900 electrons, and an equivalent noise level of ≤ 60 keV. We obtained an energy resolution of 11.2% (fwhm) for 1275 keV gamma rays from a 22 Na source. The characteristics of the PIN - preamplifier system as well as the parameters of a small CsI(Tl) - PIN detector with a direct and wavelength shifter readout are also reported. (author)

  1. Response function study of a scintillator detector of NaI(Tl)

    International Nuclear Information System (INIS)

    Villa, Marcelo Barros; Costa, Alessandro Martins da

    2014-01-01

    In measurements of gamma rays with Nai (Tl) scintillator, the detectors output data are pulse height spectra, that corresponding to distorted information about the radiation source due to various errors associated with the crystal scintillation process and electronics associated, instead of power spectra photons. Pulse height spectra are related to the real power spectra by means of scintillator detector response function NaI (Tl). In this work, the response function for a cylindrical crystal of Nal (Tl) of 7,62 x 7,62 cm (diameter x length) was studied, by Monte Carlo method, using the EGSnrc tool to model the transport of radiation, combined with experimental measurements. An inverse response matrix, even with the energy of the square root, which transforms the pulse height spectrum of photon energy spectrum was obtained. The results of this transformation of pulse height spectrum for photon energy spectrum is presented, showing that the methodology employed in this study is suitable

  2. Background studies for NaI(Tl) detectors in the ANAIS dark matter project

    International Nuclear Information System (INIS)

    Amaré, J.; Borjabad, S.; Cebrián, S.; Cuesta, C.; Fortuño, D.; García, E.; Ginestra, C.; Gómez, H.; Martínez, M.; Oliván, M. A.; Ortigoza, Y.; Solórzano, A. Ortiz de; Pobes, C.; Puimedón, J.; Sarsa, M. L.; Villar, J. A.; Villar, P.

    2013-01-01

    Several large NaI(Tl) detectors, produced by different companies, have been operated in the Canfranc Underground Laboratory (LSC) in the frame of the ANAIS (Annual modulation with NaI Scintillators) project devoted to the direct detection of dark matter. A complete background model has been developed for a 9.6 kg detector (referred as ANAIS-0 prototype) after a long data taking at LSC. Activities from the natural chains of 238 U and 232 Th, and 40 K in the NaI(Tl) crystal were evaluated applying different methods: discrimination of alpha particles vs beta/gamma background by Pulse Shape Analysis for quantifying the content of the natural chains and coincidence techniques for 40 K. Radioactive contaminations in the detector and shielding components were also determined by HPGe spectrometry. Monte Carlo simulations using Geant4 package were carried out to evaluate their contribution. At high energies, most of the measured background is nicely reproduced; at low energy some non-explained components are still present, although some plausible background sources have been analyzed. The 40 K content of the NaI(Tl) crystal has been confirmed to be the dominant contributor to the measured background with this detector. In addition, preliminary results of the background characterization, presently underway at the LSC, of two recently produced NaI(Tl) detectors, with 12.5 kg mass each, will be presented: cosmogenic induced activity has been clearly observed and is being quantified, and 40 K activity at a level ten times lower than in ANAIS-0 has been determined

  3. UV sensitivity of various solid state detectors

    International Nuclear Information System (INIS)

    Knezevic, Zeljka; Ranogajec-Komor, Maria; Miljanic, Saveta

    2008-01-01

    Full text: The light sensitivity is an important characteristic of solid state passive dosimeters used in individual, clinical and environmental dosimetry. Light sensitivity stands for the response directly induced by visible or UV light in a fully annealed material. For the above mentioned applications a negligible light sensitivity is an advantage. However, high light sensitivity and linear response allows the use of detectors as UV dosimeters. For this purpose various TL detectors and the glass element of the RPL dosemeter type SC-1 were systematically investigated after exposure to UV light (254 and 366 nm) as a function of time. The following solid state detectors were investigated relative to TLD-100: Li 2 B 4 O 7 :Cu,Ag,P LiF:Mg,Cu,P, LiF:Mg,Cu,Si, Al 2 O 3 :C and the glass element of RPL dosimeter. UV irradiations were performed with Camag UV lamp at 254 nm and at 366 nm. The illumination times were 5, 10 and 20 minutes. Day light illumination was also carried out at room temperature over time period of several hours up to 2 weeks. The UV light response of each detector was compared to the response obtained after irradiation with 137 Cs. Al 2 O 3 :C, showed high light sensitivity; after 10 minutes illumination with 254 nm UV light the response was equivalent to 130 mGy 137 Cs gamma irradiation. The 254 nm UV response of LiF:Mg,Cu,P (GR-200 A), as well as TLD-700H and Li 2 B 4 O 7 :Cu,Ag,P were proportional to the time of illumination. The responses after 10 min UV illumination were equivalent to 0.001 mGy, 0.01 mGy and 0.1 mGy 137 Cs gamma irradiation, respectively. The complete SC-1 RPL dosimeter is insensitive to light because the glass element is encapsulated in light protected holder throughout the automatic evaluation process following the annealing (irradiation, preheat, readout). The responses of the previously annealed glass element after 20 min illumination with 254 nm and 366 nm UV light were equivalent to 45μSv and 3 μSv of 137 Cs gamma

  4. YAP:Ce and CsI(Tl) detectors for dielectronic recombination experiment at the CSRm

    International Nuclear Information System (INIS)

    Wen, W.Q.; Ma, X.; Xu, W.Q.; Meng, L.J.; Zhu, X.L.; Gao, Y.; Wang, S.L.; Zhang, P.J.; Zhao, D.M.; Liu, H.P.; Zhu, L.F.; Yang, X.D.; Li, J.; Ma, X.M.; Yan, T.L.; Yang, J.C.; Yuan, Y.J.; Xia, J.W.; Xu, H.S.; Xiao, G.Q.

    2013-01-01

    Highlights: • YAP:Ce and CsI(Tl) scintillation detectors are developed to detect heavy ions at the storage ring. • A high count rate of ∼10 7 s −1 is obtained with the YAP:Ce detector for heavy ion detection. • YAP:Ce detector shows good performance for DR experiment with 3.7 MeV/u 112 Sn 35+ . -- Abstract: The storage ring CSRm in Lanzhou provides good possibilities for electron-ion collision studies with cooled ion beams. To carry on the recombination experiment at the CSRm, a scintillation detector CsI(Tl) to detect the recombined ions was developed and tested. In addition, a YAP:Ce detector has been developed and installed at CSRm and capability of handling a high count rate of ∼10 7 s −1 has been obtained which is sufficient for the future dielectronic recombination experiment at the CSRm. The comparison of the characteristics of these two detectors is presented

  5. TL detectors for gamma ray dose measurements in criticality accidents

    International Nuclear Information System (INIS)

    Miljanic, S.; Zorko, B.; Gregori, B.; Knezevic, Z.

    2007-01-01

    Determination of gamma ray dose in mixed neutron + gamma ray fields is still a demanding task. Dosemeters used for gamma ray dosimetry are usually in some extent sensitive to neutrons and their response variations depend on neutron energy i.e., on neutron spectra. Besides, it is necessary to take into account the energy dependence of dosemeter responses to gamma rays. In this work, several types of thermoluminescent detectors (TLD) placed in different holders used for gamma ray dose determination in the mixed fields were examined. Dosemeters were from three different institutions: Ruder Boskovic Inst. (RBI), Croatia, Jozef Stefan Inst. (JSI), Slovenia and Autoridad Regulatoria Nuclear (ARN), Argentina. All dosemeters were irradiated during the International Intercomparison of Criticality Accident Dosimetry Systems at the SILENE Reactor, Valduc, June 2002. Three accidental scenarios were reproduced and in each irradiation the dosemeters were exposed placed on the front of phantom and 'free in air'. Following types of TLDs were used: 7 LiF (TLD-700), CaF 2 :Mn and Al2 O3 :Mg,Y - all from RBI; CaF 2 :Mn from JSI and 7 LiF (TLD-700) from ARN. Reported doses were compared with the reference values as well as with the values obtained from the results of all participants. The results show satisfactory agreement with other dosimetry systems used in the Intercomparison. The influence of different types of holders and applied corrections of dosemeters' readings are discussed. (authors)

  6. TL detectors for gamma ray dose measurements in criticality accidents.

    Science.gov (United States)

    Miljanić, Saveta; Zorko, Benjamin; Gregori, Beatriz; Knezević, Zeljka

    2007-01-01

    Determination of gamma ray dose in mixed neutron+gamma ray fields is still a demanding task. Dosemeters used for gamma ray dosimetry are usually in some extent sensitive to neutrons and their response variations depend on neutron energy i.e., on neutron spectra. Besides, it is necessary to take into account the energy dependence of dosemeter responses to gamma rays. In this work, several types of thermoluminescent detectors (TLD) placed in different holders used for gamma ray dose determination in the mixed fields were examined. Dosemeters were from three different institutions: Ruder Bosković Institute (RBI), Croatia, JoZef Stefan Institute (JSI), Slovenia and Autoridad Regulatoria Nuclear (ARN), Argentina. All dosemeters were irradiated during the International Intercomparison of Criticality Accident Dosimetry Systems at the SILENE Reactor, Valduc, June 2002. Three accidental scenarios were reproduced and in each irradiation the dosemeters were exposed placed on the front of phantom and 'free in air'. Following types of TLDs were used: 7LiF (TLD-700), CaF2:Mn and Al2O3:Mg,Y-all from RBI; CaF2:Mn from JSI and 7LiF (TLD-700) from ARN. Reported doses were compared with the reference values as well as with the values obtained from the results of all participants. The results show satisfactory agreement with other dosimetry systems used in the Intercomparison. The influence of different types of holders and applied corrections of dosemeters' readings are discussed.

  7. Novel laser-processed CsI:Tl detector for SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Sabet, H., E-mail: hsabet@mgh.harvard.edu; Uzun-Ozsahin, D.; El-Fakhri, G. [Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02129 (United States); Bläckberg, L. [Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02129 and Department of Physics and Astronomy, Uppsala University, Uppsala 75120 (Sweden)

    2016-05-15

    Purpose: The aim of this work is to demonstrate the feasibility of a novel technique for fabrication of high spatial resolution CsI:Tl scintillation detectors for single photon emission computed tomography systems. Methods: The scintillators are fabricated using laser-induced optical barriers technique to create optical microstructures (or optical barriers) inside the CsI:Tl crystal bulk. The laser-processed CsI:Tl crystals are 3, 5, and 10 mm in thickness. In this work, the authors focus on the simplest pattern of optical barriers in that the barriers are created in the crystal bulk to form pixel-like patterns resembling mechanically pixelated scintillators. The monolithic CsI:Tl scintillator samples are fabricated with optical barrier patterns with 1.0 × 1.0 mm{sup 2} and 0.625 × 0.625 mm{sup 2} pixels. Experiments were conducted to characterize the fabricated arrays in terms of pixel separation and energy resolution. A 4 × 4 array of multipixel photon counter was used to collect the scintillation light in all the experiments. Results: The process yield for fabricating the CsI:Tl arrays is 100% with processing time under 50 min. From the flood maps of the fabricated detectors exposed to 122 keV gammas, peak-to-valley (P/V) ratios of greater than 2.3 are calculated. The P/V values suggest that regardless of the crystal thickness, the pixels can be resolved. Conclusions: The results suggest that optical barriers can be considered as a robust alternative to mechanically pixelated arrays and can provide high spatial resolution while maintaining the sensitivity in a high-throughput and cost-effective manner.

  8. Novel laser-processed CsI:Tl detector for SPECT

    International Nuclear Information System (INIS)

    Sabet, H.; Uzun-Ozsahin, D.; El-Fakhri, G.; Bläckberg, L.

    2016-01-01

    Purpose: The aim of this work is to demonstrate the feasibility of a novel technique for fabrication of high spatial resolution CsI:Tl scintillation detectors for single photon emission computed tomography systems. Methods: The scintillators are fabricated using laser-induced optical barriers technique to create optical microstructures (or optical barriers) inside the CsI:Tl crystal bulk. The laser-processed CsI:Tl crystals are 3, 5, and 10 mm in thickness. In this work, the authors focus on the simplest pattern of optical barriers in that the barriers are created in the crystal bulk to form pixel-like patterns resembling mechanically pixelated scintillators. The monolithic CsI:Tl scintillator samples are fabricated with optical barrier patterns with 1.0 × 1.0 mm"2 and 0.625 × 0.625 mm"2 pixels. Experiments were conducted to characterize the fabricated arrays in terms of pixel separation and energy resolution. A 4 × 4 array of multipixel photon counter was used to collect the scintillation light in all the experiments. Results: The process yield for fabricating the CsI:Tl arrays is 100% with processing time under 50 min. From the flood maps of the fabricated detectors exposed to 122 keV gammas, peak-to-valley (P/V) ratios of greater than 2.3 are calculated. The P/V values suggest that regardless of the crystal thickness, the pixels can be resolved. Conclusions: The results suggest that optical barriers can be considered as a robust alternative to mechanically pixelated arrays and can provide high spatial resolution while maintaining the sensitivity in a high-throughput and cost-effective manner.

  9. Compact CsI(Tl)-PIN detectors for nuclear physics applications

    International Nuclear Information System (INIS)

    Bhattacharjee, T.; Basu, S.K.; Bhattacharyya, S.; Chanda, S.; Chowdhury, A.; Mukhopadhyay, P.; Chatterjee, M.B.; Dey, C.C.; Mukherjee, Anjali

    2005-01-01

    Prototype detector elements, based on CsI(Tl) - Si PIN diodes, have been fabricated and optimized for use in a near 4p charged particle multiplicity filter array. The important aspects of fabrication of such compact detector elements along with the off-line and on-line performance test results will be reported. An early implementation of the proposed multiplicity filter array will be described. The planned use of the array in conjunction with the Indian National Gamma Array (INGA) as a reaction filter in high spin spectroscopic studies would be stressed. (author)

  10. Monitoring of garbage with a 5 x 5 NaI (Tl) detector; Monitoreo de basura con un detector de NaI (Tl) de 5 x 5

    Energy Technology Data Exchange (ETDEWEB)

    Cortes P, A.; Becerril V, A.; Angeles C, A

    1991-12-15

    So far in that is carried out the first reload of nuclear fuel in the LVC, the monitoring of garbage has been carried out using monitors trade mark Eberline model RM 14. The procedure consists in manually monitoring each object and to separate of the considered 'clean' garbage the objects considered as contaminated, which register greater or equal counts to 100 cpm. This way to process was adequate under normal operation conditions, but not in the operation rhythm that implies a bigger maintenance since the time required for monitoring from 5 to 10 kg. of garbage is of the order of 0.5 hours and the production rhythm of this it ends up being a lot but high. Due to this necessity it was thought about the problem of looking by a more efficient monitoring method. In this work a method that uses a detector of NaI (Tl) of 5 x 5 inches is discussed. (Author)

  11. Monitoring of garbage with a 5 x 5 NaI (Tl) detector; Monitoreo de basura con un detector de NaI (Tl) de 5 x 5

    Energy Technology Data Exchange (ETDEWEB)

    Cortes P, A; Becerril V, A; Angeles C, A

    1991-12-15

    So far in that is carried out the first reload of nuclear fuel in the LVC, the monitoring of garbage has been carried out using monitors trade mark Eberline model RM 14. The procedure consists in manually monitoring each object and to separate of the considered 'clean' garbage the objects considered as contaminated, which register greater or equal counts to 100 cpm. This way to process was adequate under normal operation conditions, but not in the operation rhythm that implies a bigger maintenance since the time required for monitoring from 5 to 10 kg. of garbage is of the order of 0.5 hours and the production rhythm of this it ends up being a lot but high. Due to this necessity it was thought about the problem of looking by a more efficient monitoring method. In this work a method that uses a detector of NaI (Tl) of 5 x 5 inches is discussed. (Author)

  12. The nonlinear light output of NaI(Tl) detectors in the Modular Total Absorption Spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Rasco, B.C., E-mail: crasco@lsu.edu [Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA 70803 (United States); Fijałkowska, A.; Karny, M. [Faculty of Physics, University of Warsaw, Pasteura 5, PL-02093 Warszawa (Poland); Rykaczewski, K.P. [Physics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Wolińska-Cichocka, M. [Physics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Oak Ridge Associated Universities, Oak Ridge, TN 37831 (United States); Heavy Ion Laboratory, University of Warsaw, Warsaw PL-02-093 (Poland); Grzywacz, R.; Goetz, K.C. [Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37966 (United States)

    2015-07-11

    A new detector array, the Modular Total Absorption Spectrometer (MTAS), was commissioned at the Holifield Radioactive Ion Beam Facility (HRIBF) at Oak Ridge National Lab (ORNL). Total absorption gamma spectra measured with MTAS are expected to improve beta-feeding patterns and beta strength functions in fission products. MTAS is constructed out of hexagonal NaI(Tl) detectors with a unique central module surrounded by 18 identical crystals assembled in three rings. The total NaI(Tl) mass of MTAS is over 1000 kg. The response of the central and other 18 MTAS modules to γ-radiation was simulated using the GEANT4 toolkit modified to analyze the nonlinear light output of NaI(Tl). A detailed description of the GEANT4 modifications made is discussed. Simulated energy resolution of MTAS modules is found to agree well with the measurements for single γ transitions of 662 keV ({sup 137}Cs) with 8.2% full width half maximum (FWHM), 835 keV ({sup 54}Mn) with FWHM of 7.5% FWHM, and 1115 keV ({sup 65}Zn) with FWHM of 6.5%. Simulations of single and multiple γ-rays from {sup 60}Co are also discussed.

  13. Large solid angle detectors (low energy)

    International Nuclear Information System (INIS)

    L'Hote, D.

    1988-01-01

    This lecture deals with large solid angle detectors used in low energy experiments (mainly in Nuclear Physics). The reasons for using such detectors are discussed, and several basic principles of their design are presented. Finally, two examples of data analysis from such detectors are given [fr

  14. Expanding of FOV of NaI(Tl) gamma camera detectors-Is it possible?

    International Nuclear Information System (INIS)

    Gayshan, Vadim L.; Gektin, A.V.; Boyarintsev, A.; Pedash, V.

    2006-01-01

    Every gamma camera detector used for medical imaging of conventional design faces the problem of distorted or no information readout at the areas closer to the edge of detectors. Obtaining position and energy information becomes almost impossible at distance 0-12 of PMT size from the edge. Therefore, in some designs were proposed losing of edge energy resolution while improving in spatial uniformity when it comes to imaging at the edges. This work is dedicated to understanding of the problem, mathematical simulations, practical tests and recommendations to build detectors with larger usable FOV without increasing in dimensions. To study the problem we built the test jig with linear motion source and readout electronics to simulate gamma cameras of PMTs. Based on simulation results the idea of modifying of crystal shape combined with specific light redirection system of baffles was tested and allowed to expand usable FOV. The results are presented and showed that for traditional NaI(Tl) scintillators using 2'' PMT may be possible to obtain relatively good spatial resolution starting from 4-5mm from the edge of a detector. The question of economical efficiency of proposed method is being investigated and a special detector manufacturing technology must be developed to accommodate this. While we believe that achieved results are very important for small size detectors (<20cm) they could be beneficial even for larger detectors used in whole body imaging systems

  15. Calibrating the CsI(Tl) detectors of the GARFIELD apparatus

    CERN Document Server

    Abbondanno, U; Casini, G; Cavaletti, R; Cavallaro, S; Chiari, M; D'Agostino, M; Gramegna, F; Lanchais, A; Margagliotti, G V; Mastinu, P F; Milazzo, P M; Moroni, A; Nannini, A; Ordine, A; Vannini, G; Vannucci, L

    2002-01-01

    The energy and charge dependence of the light output of the CsI(Tl) detectors of the GARFIELD apparatus has been investigated for heavy ions with 5<=Z<=16 in the energy range from 2.2 to 8.3 A MeV. The results have been compared to an analytical expression successfully used in previous calibration procedures at higher energies, and a rather good agreement was obtained between measured and calculated quantities. The resulting parameter set was successfully applied to another set of experimental data. The overall result demonstrates the validity of the above mentioned calibration procedure in a wide range of incident ion energies and masses.

  16. Design and implementation of the NaI(Tl)/CsI(Na) detectors output signal generator

    International Nuclear Information System (INIS)

    Zhou Xu; Liu Congzhan; Zhao Jianling

    2014-01-01

    We designed and implemented a signal generator that can simulate the output of the NaI(Tl)/CsI(Na) detectors' pre-amplifier onboard the Hard X-ray Modulation Telescope (HXMT). Using the development of the FPGA (Field Programmable Gate Array) with VHDL language and adding a random constituent, we have finally produced the double exponential random pulse signal generator. The statistical distribution of the signal amplitude is programmable. The occurrence time intervals of the adjacent signals contain negative exponential distribution statistically. (authors)

  17. Design and implementation of the NaI(Tl)/CsI(Na) detectors output signal generator

    Science.gov (United States)

    Zhou, Xu; Liu, Cong-Zhan; Zhao, Jian-Ling; Zhang, Fei; Zhang, Yi-Fei; Li, Zheng-Wei; Zhang, Shuo; Li, Xu-Fang; Lu, Xue-Feng; Xu, Zhen-Ling; Lu, Fang-Jun

    2014-02-01

    We designed and implemented a signal generator that can simulate the output of the NaI(Tl)/CsI(Na) detectors' pre-amplifier onboard the Hard X-ray Modulation Telescope (HXMT). Using the development of the FPGA (Field Programmable Gate Array) with VHDL language and adding a random constituent, we have finally produced the double exponential random pulse signal generator. The statistical distribution of the signal amplitude is programmable. The occurrence time intervals of the adjacent signals contain negative exponential distribution statistically.

  18. Study of method of efficiency transference using detectors NaI(Ti); Estudo de método de transferência de eficiência usando detectores NaI(Tl)

    Energy Technology Data Exchange (ETDEWEB)

    Ramos, Thiago L.; Salgado, César M., E-mail: thiago_lins-ramos@hotmail.com, E-mail: otero@ien.gov.br [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2017-07-01

    The use of NaI (Tl) scintillation detectors for measurements implies the determination of the detection efficiency as a function of the energy of the incident photons. The efficiency curve can be obtained experimentally with the use of several mono-energy sources calibrated with emission energies covering the whole range of interest or using the Monte Carlo method. The Institute of Nuclear Engineering develops several methodologies using these detectors as they are robust, inexpensive and do not need cooling for their use. The assembly of an experimental arrangement is usually complex, since several factors influence the result affecting reproducibility in measurements, such as: parallelism between source and detector, alignment between source and detector, and accuracy of source-detector distance. In view of such difficulties, an automated positioning system was developed for the source-detector set controlled by a micro controller based on the ARDUINO language in order to guarantee the reproducibility in the experimental arrangements. In the initial phase of this study, a mathematical model was developed in the MCNP-X code using a NaI (Tl) detector. A theoretical validation using the Efficiency Transfer Method was performed at three different positions on the detector's axial axis (10.6 cm, 11.3 cm and 12.0 cm). This method is based on the ratio of effective solid angles. The experimental validation presented maximum relative errors of 7.74% for the position 11.3 cm.

  19. Improved performances of CsI(Tl) scintillation detectors for DIAMANT II multidetector

    International Nuclear Information System (INIS)

    Scheurer, J-N.; Virassamynaiken, E.; Kalinka, G.; Nyako, B.M.; Gal, J.

    1997-01-01

    The scintillation detectors used for light particle discrimination require a careful optimization of performances of the scintillator-light guide assembly to ensure a good light channeling to photodiode. To obtain a good energy resolution and a good peak symmetry such an optimization has been carried out on the 'Chess-Board' detectors consisting of 25 units, a system which is to be utilised as additional detector at EUROBALL. Recently, such optimization has been realised also for the detectors of the DIAMANT II assembly. This multidetector includes the 'Chess-Board' and constitutes a more segmented version of DIAMANT with 82 detectors instead of 54 detectors. The ensemble of these charged light particle detectors is to be incorporated in EUROBALL. For the first newly conditioned 34 detectors the light collection and the energy resolution measured for 5.5 MeV α particles equal 70 ± 3% and 2.4 ± 0.2%, respectively. The best result was obtained with 232 U as a α particle source and using a 6 μs time constant amplifier. The line shape of the spectrum peaks can be described by the function 1/(E 0 - E) 1-α convoluted with Lorentz and Gauss functions. For the peak of 8.7 MeV, measured with the CsI (Tl) detector, the asymmetry is as low as α 0.02 while the Gaussian and Lorentzian widths are given by 2 Γ/E 0 0.005 and 2.35 σ/E 0 = 0.019

  20. Characterization and analysis of NaI(Tl) and BGO detectors

    International Nuclear Information System (INIS)

    Harrison, J.R.

    1994-01-01

    There have been many studies concerning the performance characteristics of NaI(Tl) and BGO scintillating crystals, most of which generate data by algorithms rather than from experimentation. Those studies which do deal with collected data, however, usually test only a few detecting units. It was, therefore, the purpose of this project to develop a characterization method and to characterize a large number of scintillators of various sizes and histories as well as to create a performance profile based on the data collected. The energy ranges at which the detectors show relatively good resolution % and photo peak efficiency was also desired for future reference. Enough statistical data was collected and analyzed so that a differentiation between those detectors which perform well and those that do not can be made

  1. NaI(Tl) detectors modeling in MCNP-X and Gate/Geant4 codes

    Energy Technology Data Exchange (ETDEWEB)

    Affonso, Renato Raoni Werneck; Silva, Ademir Xavier da, E-mail: raoniwa@yahoo.com.br, E-mail: ademir@nuclear.ufrj.br [Coordenacao de Pos-Graduacao e Pesquisa de Engenharia (PEN/COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Nuclear; Salgado, Cesar Marques, E-mail: otero@ien.gov.br [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2017-07-01

    NaI (Tl) detectors are widely used in gamma-ray densitometry, but their modeling in Monte Carlo codes, such as MCNP-X and Gate/Geant4, needs a lot of work and does not yield comparable results with experimental arrangements, possibly due to non-simulated physical phenomena, such as light transport within the scintillator. Therefore, it is necessary a methodology that positively impacts the results of the simulations while maintaining the real dimensions of the detectors and other objects to allow validating a modeling that matches up with the experimental arrangement. Thus, the objective of this paper is to present the studies conducted with the MCNPX and Gate/Geant4 codes, in which the comparisons of their results were satisfactory, showing that both can be used for the same purposes. (author)

  2. On the elimination of the afterglow of CsI(Tl) scintillation detector

    International Nuclear Information System (INIS)

    Alfassi, Z.B.; Ifergan, Y.; Wengrowicz, U.; Weinstein, Marcelo

    2009-01-01

    The use of CsI(Tl) in survey meters is limited to low dose-rate fields due to the afterglow effect, which can take up to 20 min in case of 120 s exposure to 4 R/h field. Even mixtures of low and high dose-rate fields are prohibited since the afterglow effect of the high dose-rate field prevents the use of the meter in the low dose-rate field. It was found that heating the scintillation detector to 60 deg. C shortened considerably the time of the afterglow effect to 3 s, even after exposure of 120 s to fields of 4 R/h. It is suggested to start heating the detector immediately when reaching high dose-rate field and adjusting the calibration to the measured temperature.

  3. Gamma spectra analysis from a NaI(Tl) scintillation detector using a micro-computer

    International Nuclear Information System (INIS)

    Levinson, S.

    1990-01-01

    A software package of programs was devloped for qualitative and quantitative evaluation of gamma ray spectra obtained from a NaI(Tl) scintilation counter, by means of a micro-computer. The programs can easily be transformed for use with a Ge(Li) detector. The various algorithms enable automatic analyzing of a spectrum and also interactive or manual mode. The graphic programs display the measured spectrum as well as spectra of standard radionuclides which helps in the determination of peaks and related radionuclides in the spectrum. The peak search is carried out on a smoothed spectrum and is done by checking the behaviour of the second and third derivatives. The algorithm solves the problem of overlapping peaks and performs gaussian fitting, if necessary. Determination of the various radionuclides in the spectrum is done by linear minimum least squares techniques. Overall analysis of the radionuclides activities in the spectrum is obtained for samples of various counting geometries. In addition, a model was developed for efficiency calibration of flat 3X3 inch NaI(Tl) detectors for different samples measured in various counting geometries. It is based on point source experimental efficiency curve fitting. (author)

  4. Response function of NaI(Tl) detectors and multiple backscattering of gamma rays in aluminium

    International Nuclear Information System (INIS)

    Sabharwal, Arvind D.; Singh, Manpreet; Singh, Bhajan; Sandhu, B.S.

    2008-01-01

    The response function, converting the observed pulse-height distribution of a NaI(Tl) detector to a true photon spectrum, is obtained experimentally with the help of an inverse matrix approach. The energy of gamma-ray photons continuously decreases as the number of scatterings increases in a sample having finite dimensions when one deals with the depth of the sample. The present experiments are undertaken to study the effect of target thickness on intensity distribution of gamma photons multiply backscattered from an aluminium target. A NaI(Tl) gamma-ray detector detects the photons backscattered from the aluminium target. The subtraction of analytically estimated singly scattered distribution from the observed intensity distribution (originating from interactions of primary gamma-ray photons with the target) results in multiply backscattered events. We observe that for each incident gamma photon energy, the number of multiply backscattered photons increases with increase in target thickness and then saturates at a particular target thickness called the saturation thickness (depth). Saturation thickness for multiply backscattering of gamma photons is found to decrease with increase in energy of incident gamma-ray photons

  5. Particle identification method in the CsI(Tl) scintillator used for the CHIMERA 4 pi detector

    CERN Document Server

    Alderighi, M; Basssini, R; Berceanu, I; Blicharska, J; Boiano, C; Borderie, B; Bougault, R; Bruno, M; Cali, C; Cardella, G; Cavallaro, S; D'Agostino, M; D'andrea, M; Dayras, R; De Filippo, E; Fichera, F; Geraci, E; Giustolisi, F; Grzeszczuk, A; Guardone, N; Guazzoni, P; Guinet, D; Iacono-Manno, M; Kowalski, S; La Guidara, E; Lanchais, A L; Lanzalone, G; Lanzanò, G; Le Neindre, N; Li, S; Maiolino, C; Majka, Z; Manfredi, G; Nicotra, D; Paduszynski, T; Pagano, A; Papa, M; Petrovici, C M; Piasecki, E; Pirrone, S; Politi, G; Pop, A; Porto, F; Rivet, M F; Rosato, E; Sacca, G; Sechi, G; Simion, V; Sperduto, M L; Steckmeyer, J C; Trifiró, A; Trimarchi, M; Urso, S; Vannini, G; Vigilante, M; Wilczynski, J; Wu, H; Xiao, Z; Zetta, L; Zipper, W

    2002-01-01

    The charged particle identification obtained by the analysis of signals coming from the CsI(Tl) detectors of the CHIMERA 4 pi heavy-ion detector is presented. A simple double-gate integration method, with the use of the cyclotron radiofrequency as reference time, results in low thresholds for isotopic particle identification. The dependence of the identification quality on the gate generation timing is discussed. Isotopic identification of light ions up to Beryllium is clearly seen. For the first time also the identification of Z=5 particles is observed. The identification of neutrons interacting with CsI(Tl) by (n,alpha) and (n,gamma) reactions is also discussed.

  6. Implantation of a 4πγ, with well type Nal(Tl) detector, for calibration of gamma emitters radionuclides

    International Nuclear Information System (INIS)

    Barros, Douglas Cisneiros de

    2001-04-01

    Among the absolute calibration methods for activity quantity of radionuclides the most used in the metrology laboratories are: the 4πβγ coincidence counting), defined solid angle counting, sum-peak (or γ-γ coincidence) and 4π γ method. The 4πγ method is appropriate to measure the activity of radionuclides with complex decay scheme and its implementation at Laboratorio Nacional de Metrologia das Radiacoes Ionizantes, commissioned by INMETRO from 1989, will provide to the expansion of the jobs to supply the users by standard radioactive sources. The determination of activity can be made using calibration factor and/or the efficiency curve. For the implantation of this calibration method at LNMRI, after the selection of the detector and the electronic instrumentation, the attainment of the efficiency curve in function of gamma rays energy, standard sources with one or two peaks each were used. The method is based in ε Τ = Πι (1 - ε ΤΕ ι) where ΕΤ is the total efficiency for each radionuclide and eTi is the efficiency for each gamma transition of this radionuclide. The detector selected was a 8 x 8'' well type Nal(Tl), with well dimensions 6'' deep and 3'' of diameter, from Harshaw The standards sources used are: Am-241, Pb- 210, Mn-54, Co-57, Cd-109, Ce-139, Co-60, Na-22, Y-88 and Zn-65. The preliminary results are consistent with the literature. (author)

  7. Electronically shielded solid state charged particle detector

    International Nuclear Information System (INIS)

    Balmer, D.K.; Haverty, T.W.; Nordin, C.W.; Tyree, W.H.

    1996-01-01

    An electronically shielded solid state charged particle detector system having enhanced radio frequency interference immunity includes a detector housing with a detector entrance opening for receiving the charged particles. A charged particle detector having an active surface is disposed within the housing. The active surface faces toward the detector entrance opening for providing electrical signals representative of the received charged particles when the received charged particles are applied to the active surface. A conductive layer is disposed upon the active surface. In a preferred embodiment, a nonconductive layer is disposed between the conductive layer and the active surface. The conductive layer is electrically coupled to the detector housing to provide a substantially continuous conductive electrical shield surrounding the active surface. The inner surface of the detector housing is supplemented with a radio frequency absorbing material such as ferrite. 1 fig

  8. Determination of the response of a NaI(Tl) detector; Determinacion de la respuesta de un detector de NaI(Tl)

    Energy Technology Data Exchange (ETDEWEB)

    Vega C, H.R.; Manzanares A, E.; Hernandez D, V.M.; Chacon R, A. [Universidad Autonoma de Zacatecas, A.P. 336, 98000 Zacatecas (Mexico)]. e-mail: fermineutron@yahoo.com

    2006-07-01

    By means of Monte Carlo calculations it was determined the response of a scintillator of NaI (Tl) of 7.62 {phi} x 7.62 cm to monoenergetic gamma rays of 0.2 to 3.5 MeV. The response allows to determine the spectra of height of pulses of the monoenergetic photons. This type of calculations was also carried out for photons emitted by sources of Cs-137, Co-60, Na-22, Na-24 and {sup 239} PuBe, with the purpose of reproducing the gamma spectra obtained with this type of detecting. In the calculations the detector was modelled as a NaI cylinder with Al cover and the base of lucite; due to the absence of reliable information on the quantity of thallium in the calculations this information was omitted: for photons whose energy is greater to 1.022 MeV the presence of the gamma peak of the simple escape and twice is observed. The source was modelled as punctual and was located to 5 cm along the axial axis of the detector. To verify the calculations its were carried out measurements with a spectrometer with a scintillator of 7.62 {phi} x 7.62 cm. In the measured spectra the sum peak is observed, while in those calculated it doesn't appear; because the simultaneous detection of photons of different energy doesn't happen each photon since, in single form, it is followed until its complete absorption in the scintillator or when it escapes from the volume of the detector. To reproduce the sum peak and to obtain height spectra of pulses similar to those measured, the sum photons were introduced in the calculations. With the purpose of that Monte Carlo calculation it reproduces the scattering around the photopeak it was used a gaussian function in each photopeak whose characteristics were obtained starting from the experimental data. The calculation of the response of a scintillator allows to establish the capacity of the measurement of the gamma radiation as well as to distinguish the real events of those that appear by the limitations of the detection process. (Author)

  9. Monitoring of garbage with a 5x5NaI (Tl) detector

    International Nuclear Information System (INIS)

    Cortes P, A.; Becerril V, A.; Angeles C, A.

    1991-12-01

    So far in that is carried out the first reload of nuclear fuel in the LVC, the monitoring of garbage has been carried out using monitors trade mark Eberline model RM 14. The procedure consists in manually monitoring each object and to separate of the considered 'clean' garbage the objects considered as contaminated, which register greater or equal counts to 100 cpm. This way to process was adequate under normal operation conditions, but not in the operation rhythm that implies a bigger maintenance since the time required for monitoring from 5 to 10 kg. of garbage is of the order of 0.5 hours and the production rhythm of this it ends up being a lot but high. Due to this necessity it was thought about the problem of looking by a more efficient monitoring method. In this work a method that uses a detector of NaI (Tl) of 5 x 5 inches is discussed. (Author)

  10. Full energy peak efficiency of NaI(Tl) gamma detectors and its analytical and semi-empirical representations

    International Nuclear Information System (INIS)

    Sudarshan, M.; Joseph, J.; Singh, R.

    1992-01-01

    The validity of various analytical functions and semi-empirical formulae proposed for representing the full energy peak efficiency (FEPE) curves of Ge(Li) and HPGe detectors has been tested for the FEPE of 7.6 cm x 7.6 cm and 5 cm x 5 cm Nal(Tl) detectors in the gamma energy range from 59.5 to 1408.03 keV. The functions proposed by East, and McNelles and Campbell provide by far the best representations of the present data. The semi-empirical formula of Mowatt describes the present data very well. The present investigation shows that some of the analytical functions and semi-empirical formulae, which represent the FEPE of the Ge(Li) and HPGe detectors very well, can be quite fruitfully used for Nal(Tl) detectors. (Author)

  11. Individual TL detector characteristics in automated processing of personnel dosemeters: correction factors as extension to identity codes of dosemeter cards

    International Nuclear Information System (INIS)

    Toivonen, Matti.

    1979-07-01

    One, two and three-component dosemeter cards and their associated processing equipment were developed for personnel monitoring. A novel feature of the TLD system is that the individual sensitivity correction factors of TL detectors for β/γ radiation dosimetry and special timing factors for the readout of neutron detectors are stored on dosemeter cards as an extension of the identity codes. These data are utilized in the automatic TL reading process with the aim of cancelling out the influence of the individual detector characteristics on the measuring results. Stimulation of TL is done with hot nitrogen without removing the detectors from their cards and without any metal contact. Changes in detector characteristics are thus improbable. The reading process can be adjusted in a variety of ways. For example, each detector in the same card can be processed with optimal heating and the specific 250 deg C glow peak of neutron radiation can be roughly separated from the main LiF glow peaks. (author)

  12. Calibration of a single hexagonal NaI(Tl) detector using a new numerical method based on the efficiency transfer method

    Energy Technology Data Exchange (ETDEWEB)

    Abbas, Mahmoud I., E-mail: mabbas@physicist.net [Physics Department, Faculty of Science, Alexandria University, 21511 Alexandria (Egypt); Badawi, M.S. [Physics Department, Faculty of Science, Alexandria University, 21511 Alexandria (Egypt); Ruskov, I.N. [Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Institute for Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences, 1784 Sofia (Bulgaria); El-Khatib, A.M. [Physics Department, Faculty of Science, Alexandria University, 21511 Alexandria (Egypt); Grozdanov, D.N. [Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Institute for Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences, 1784 Sofia (Bulgaria); Thabet, A.A. [Department of Medical Equipment Technology, Faculty of Allied Medical Sciences, Pharos University in Alexandria (Egypt); Kopatch, Yu.N. [Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Gouda, M.M. [Physics Department, Faculty of Science, Alexandria University, 21511 Alexandria (Egypt); Skoy, V.R. [Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation)

    2015-01-21

    Gamma-ray detector systems are important instruments in a broad range of science and new setup are continually developing. The most recent step in the evolution of detectors for nuclear spectroscopy is the construction of large arrays of detectors of different forms (for example, conical, pentagonal, hexagonal, etc.) and sizes, where the performance and the efficiency can be increased. In this work, a new direct numerical method (NAM), in an integral form and based on the efficiency transfer (ET) method, is used to calculate the full-energy peak efficiency of a single hexagonal NaI(Tl) detector. The algorithms and the calculations of the effective solid angle ratios for a point (isotropic irradiating) gamma-source situated coaxially at different distances from the detector front-end surface, taking into account the attenuation of the gamma-rays in the detector's material, end-cap and the other materials in-between the gamma-source and the detector, are considered as the core of this (ET) method. The calculated full-energy peak efficiency values by the (NAM) are found to be in a good agreement with the measured experimental data.

  13. Some solid state properties of LiF:Mg,Cu,P TL-materials

    Energy Technology Data Exchange (ETDEWEB)

    Prokert, K [Dresden Univ. of Technology (Georgia). Inst. of Radiation Protection

    1996-12-31

    This paper describes some investigations of solid state characteristics of a LiF:Mg,Cu,P thermoluminofor. The investigations were carried out with LiF:Mg,Cu,P-thermoluminescence (TL)-material prepared by the chemical institute of the Moscow State University in form of powder and sintered pellets. Following methods were used: (1) Studies of the chemical composition was carried out by x-ray fluorescence analysis with `SPECTRO-X-LAB`-equipment with Rh-anode, B{sub 4}C-polarizator, LN{sub 2}-cooled 30 mm{sup 2} Si(Li)-detector with Be-window (energy resolution 155 keV for Mn-k{sub {alpha}}-radiation). The software of the equipment permits a qualitative and quantitative determination of elements with atomic numbers >10; (2) investigations of the crystal structure were taken by x-ray-diffractometry with a SIEMENS-diffractometer D 500 using Cu-k{sub {alpha}}-radiation. The integrated software permits to analyze the crystalline phases using the data of the measured material by comparison with standards spectra of various pure substances. The results of determination of the chemical composition and the crystal structure show that in the thermoluminofor LiF:Mg,Cu,P, besides the basic material LiF also Li{sub 3}PO{sub 4}- and Li{sub 4}P{sub 2}O{sub 7}-crystal regions exists. The occurrence of the two lithium phosphate phases follow from the high ammonium phosphate content in the mixture for the thermoluminofor production. The formation of the various lithium phosphates depends from state of dehydration of phosphoric acids, created by thermal decomposition of NH{sub 4}H{sub 2}PO{sub 4} before their reactions with LiF start. Therefore the content of these compounds can differ if thermoluminofors are prepared under various conditions. The maintenance of the needed equilibrium of special structures in the material depends on the preparation procedure, on the reading and annealing methods. Typically for such an equilibrium is its poor thermal stability. (Abstract Truncated)

  14. Frequency Domain Multiplexing for Use With NaI[Tl] Detectors

    Science.gov (United States)

    Belling, Samuel; Coherent Collaboration

    2017-09-01

    A process used in many forms of signal communication known as multiplexing is adapted for the purpose of combining signals from NaI[Tl] detectors so that fewer digitizer channels can be used to process the signal information from large experiments within the COHERENT collaboration. Each signal is passed through a ringing circuit to modulate it with a characteristic frequency. Information about the signal can be extracted from its amplitude, frequency, and phase. Simulations in LTSpice show that an operational amplifier circuit with a parallel LRC feedback loop can serve as the modulating circuit. Several such circuits can be constructed and housed compactly in a unit, and fed to an inverting, summing amplifier with tunable gain, such that the signals are carried by one cable. The signals are analyzed based on a Fourier transform after being digitized. The results show that the energy, channel, and time of the original interaction can be recovered by this process. In some cases it is possible through filtering and deconvolution to recover the shape of the original signal. The effort is ongoing, but with the design presented it is possible to multiplex 10 detectors into a single digitizer channel. NSF REU Program at Duke University.

  15. Efficiency calibration and coincidence summing correction for large arrays of NaI(Tl) detectors in soccer-ball and castle geometries

    International Nuclear Information System (INIS)

    Anil Kumar, G.; Mazumdar, I.; Gothe, D.A.

    2009-01-01

    Efficiency calibration and coincidence summing correction have been performed for two large arrays of NaI(Tl) detectors in two different configurations. They are, a compact array of 32 conical detectors of pentagonal and hexagonal shapes in soccer-ball geometry and an array of 14 straight hexagonal NaI(Tl) detectors in castle geometry. Both of these arrays provide a large solid angle of detection, leading to considerable coincidence summing of gamma rays. The present work aims to understand the effect of coincidence summing of gamma rays while determining the energy dependence of efficiencies of these two arrays. We have carried out extensive GEANT4 simulations with radio-nuclides that decay with a two-step cascade, considering both arrays in their realistic geometries. The absolute efficiencies have been simulated for gamma energies from 700 to 2800 keV using four different double-photon emitters, namely, 60 Co, 46 Sc, 94 Nb and 24 Na. The efficiencies so obtained have been corrected for coincidence summing using the method proposed by Vidmar et al. . The simulations have also been carried out for the same energies assuming mono-energetic point sources, for comparison. Experimental measurements have also been carried out using calibrated point sources of 137 Cs and 60 Co. The simulated and the experimental results are found to be in good agreement. This demonstrates the reliability of the correction method for efficiency calibration of two large arrays in very different configurations.

  16. Efficiency calibration and coincidence summing correction for large arrays of NaI(Tl) detectors in soccer-ball and castle geometries

    Energy Technology Data Exchange (ETDEWEB)

    Anil Kumar, G., E-mail: anilg@tifr.res.i [Department of Nuclear and Atomic Physics, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005 (India); Mazumdar, I.; Gothe, D.A. [Department of Nuclear and Atomic Physics, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005 (India)

    2009-11-21

    Efficiency calibration and coincidence summing correction have been performed for two large arrays of NaI(Tl) detectors in two different configurations. They are, a compact array of 32 conical detectors of pentagonal and hexagonal shapes in soccer-ball geometry and an array of 14 straight hexagonal NaI(Tl) detectors in castle geometry. Both of these arrays provide a large solid angle of detection, leading to considerable coincidence summing of gamma rays. The present work aims to understand the effect of coincidence summing of gamma rays while determining the energy dependence of efficiencies of these two arrays. We have carried out extensive GEANT4 simulations with radio-nuclides that decay with a two-step cascade, considering both arrays in their realistic geometries. The absolute efficiencies have been simulated for gamma energies from 700 to 2800 keV using four different double-photon emitters, namely, {sup 60}Co, {sup 46}Sc, {sup 94}Nb and {sup 24}Na. The efficiencies so obtained have been corrected for coincidence summing using the method proposed by Vidmar et al. . The simulations have also been carried out for the same energies assuming mono-energetic point sources, for comparison. Experimental measurements have also been carried out using calibrated point sources of {sup 137}Cs and {sup 60}Co. The simulated and the experimental results are found to be in good agreement. This demonstrates the reliability of the correction method for efficiency calibration of two large arrays in very different configurations.

  17. (99m)Tc-MDP bone scintigraphy of the hand: comparing the use of novel cadmium zinc telluride (CZT) and routine NaI(Tl) detectors.

    Science.gov (United States)

    Koulikov, Victoria; Lerman, Hedva; Kesler, Mikhail; Even-Sapir, Einat

    2015-12-01

    Cadmium zinc telluride (CZT) solid-state detectors have been recently introduced in the field of nuclear medicine in cardiology and breast imaging. The aim of the current study was to evaluate the performance of the novel detectors (CZT) compared to that of the routine NaI(Tl) in bone scintigraphy. A dual-headed CZT-based camera dedicated originally to breast imaging has been used, and in view of the limited size of the detectors, the hands were chosen as the organ for assessment. This is a clinical study. Fifty-eight consecutive patients (total 116 hands) referred for bone scan for suspected hand pathology gave their informed consent to have two acquisitions, using the routine camera and the CZT-based camera. The latter was divided into full-dose full-acquisition time (FD CZT) and reduced-dose short-acquisition time (RD CZT) on CZT technology, so three image sets were available for analysis. Data analysis included comparing the detection of hot lesions and identification of the metacarpophalangeal, proximal interphalangeal, and distal interphalangeal joints. A total of 69 hot lesions were detected on the CZT image sets; of these, 61 were identified as focal sites of uptake on NaI(Tl) data. On FD CZT data, 385 joints were identified compared to 168 on NaI(Tl) data (p < 0.001). There was no statistically significant difference in delineation of joints between FD and RD CZT data as the latter identified 383 joints. Bone scintigraphy using a CZT-based gamma camera is associated with improved lesion detection and anatomic definition. The superior physical characteristics of this technique raised a potential reduction in administered dose and/or acquisition time without compromising image quality.

  18. Point Defect Properties of Cd(Zn)Te and TlBr for Room-Temperature Gamma Radiation Detectors

    Science.gov (United States)

    Lordi, Vincenzo

    2013-03-01

    The effects of various crystal defects in CdTe, Cd1-xZnxTe (CZT), and TlBr are critical for their performance as room-temperature gamma radiation detectors. We use predictive first principles theoretical methods to provide fundamental, atomic scale understanding of the defect properties of these materials to enable design of optimal growth and processing conditions, such as doping, annealing, and stoichiometry. Several recent cases will be reviewed, including (i) accurate calculations of the thermodynamic and electronic properties of native point defects and point defect complexes in CdTe and CZT; (ii) the effects of Zn alloying on the native point defect properties of CZT; (iii) point defect diffusion and binding related to Te clustering in Cd(Zn)Te; (iv) the profound effect of native point defects--principally vacancies--on the intrinsic material properties of TlBr, particularly electronic and ionic conductivity; (v) tailored doping of TlBr to independently control the electronic and ionic conductivity; and (vi) the effects of metal impurities on the electronic properties and device performance of TlBr detectors. Prepared by LLNL under Contract DE-AC52-07NA27344 with support from the National Nuclear Security Administration Office of Nonproliferation and Verification Research and Development NA-22.

  19. A Comparison between HPGe and NaI(Tl) detectors performance for gamma-spectrometry of low level measurement

    International Nuclear Information System (INIS)

    Poursiamy, N. H.; Tajikahmadi, H.; Mirshojaei, S. F.

    2005-01-01

    According to progressive usage of nuclear technology, it's important to prevent the contamination of the environment by man-made radioisotopes and exposures of human being. Radioisotopes can enter the human body by inhalation and ingestion which are the most important ways to internal exposures. Measurement of radiation level in foodstuff is one of the most important parameters in environmental safety which is performed according to constitution and standard tests in most countries such as Iran. Gamma spectrometry is carried out by NaI(Tl) and HPGe detector systems for foodstuffs. In this research operation of HPGe and NaI(Tl) detectors in gamma spectrometry with a standard radioactive source are investigated and compared. Also the result of NaI superiority in foodstuff radiation measurement given

  20. Photopeak efficiency response function of an underwater gamma-ray NaI(Tl) detector using MCNP-X

    International Nuclear Information System (INIS)

    Salgado, William L.; Silva, Ademir X.; Salgado, Cesar M.

    2015-01-01

    This work presents a study to calculate the response function of a 1.5″ x 1″ NaI(Tl) scintillation detector when it is used in the marine environment in the energy range from 20 keV to 662 keV. The method takes into account both the scattering of photons in the water and the detection mechanism of the detector. In addition, the calculation of the response function of the whole system is essential for suppressing the background of the measurement and for estimating the concentration of the involved radionuclides, especially given the greater probability of primary gamma photons undergoing multiple scattering events before they interact with the detector. The experimental photopeak efficiency measurements for point sources were compared with the simulated results under the same conditions of the experimental setup to validate the simulation of the detector. Monte Carlo simulations were performed using the MCNP-X code for the investigation of gamma-ray absorption in water in different brines. The energy resolution curve was used to improve the response of the mathematical simulation of the detector. The detector’s simulation was based on information obtained from the gammagraphy technique. Both dimensions and materials were used for the calculation with the MCNP-X code. The photopeak efficiency of a NaI(Tl) detector for different radionuclides in the aquatic environment with different salinities was calculated. (author)

  1. Investigation and optimisation of mobile NaI(Tl) and 3He-based neutron detectors for finding point sources

    International Nuclear Information System (INIS)

    Nilsson, Jonas M.C.; Finck, Robert R.; Rääf, Christopher

    2015-01-01

    Neutron radiation produces high-energy gamma radiation through (n,γ) reactions in matter. This can be used to detect neutron sources indirectly using gamma spectrometers. The sensitivity of a gamma spectrometer to neutrons can be amplified by surrounding it with polyvinyl chloride (PVC). The hydrogen in the PVC acts as a moderator and the chlorine emits prompt gammas when a neutron is captured. A 4.7-l 3 He-based mobile neutron detector was compared to a 4-l NaI(Tl)-detector covered with PVC using this principle. Methods were also developed to optimise the measurement parameters of the systems. The detector systems were compared with regard to their ability to find 241 AmBe, 252 Cf and 238 Pu– 13 C neutron sources. Results from stationary measurements were used to calculate optimal integration times as well as minimum detectable neutron emission rates. It was found that the 3 He-based detector was more sensitive to 252 Cf sources whereas the NaI(Tl) detector was more sensitive to 241 AmBe and 238 Pu– 13 C sources. The results also indicated that the sensitivity of the detectors to sources at known distances could theoretically be improved by 60% by changing from fixed integration times to list mode in mobile surveys

  2. Theoretical calibration of a NaI(Tl) detector for the measurement of 131I in a thyroid phantom

    International Nuclear Information System (INIS)

    Venturini, Luzia

    2002-01-01

    This paper describes the theoretical calibration of a NaI(Tl) detector using Monte Carlo Method, for the measurement of 131 I in a thyroid phantom. The thyroid is represented by the region between two concentric cylinders, where the inner one represents the trachea and the outer one represents the neck. 133 Ba was used for experimental calibration. The results shows that the calibration procedure is suitable for 131 I measurements. (author)

  3. Design, instrumentation and response characteristics of a 2 pi multi-detector of CsI(Tl) scintillators mounted inside the Plastic Ball spectrometer

    NARCIS (Netherlands)

    Joulaeizadeh, L.; Gasparic, I.; Bacelar, J.; Caplar, R.; Löhner, H.

    2010-01-01

    A 2 pi hemispherical detector consisting of 64 CsI(Tl) scintillator modules covering the angular range of 80 degrees -160 degrees has been constructed. This detector is employed as the Inner Shell of the Plastic Ball detector and was used in two experimental programs concerning the study of pionic

  4. Determination of the response of a NaI(Tl) detector

    International Nuclear Information System (INIS)

    Vega C, H.R.; Manzanares A, E.; Hernandez D, V.M.; Chacon R, A.

    2006-01-01

    By means of Monte Carlo calculations it was determined the response of a scintillator of NaI (Tl) of 7.62 Φ x 7.62 cm to monoenergetic gamma rays of 0.2 to 3.5 MeV. The response allows to determine the spectra of height of pulses of the monoenergetic photons. This type of calculations was also carried out for photons emitted by sources of Cs-137, Co-60, Na-22, Na-24 and 239 PuBe, with the purpose of reproducing the gamma spectra obtained with this type of detecting. In the calculations the detector was modelled as a NaI cylinder with Al cover and the base of lucite; due to the absence of reliable information on the quantity of thallium in the calculations this information was omitted: for photons whose energy is greater to 1.022 MeV the presence of the gamma peak of the simple escape and twice is observed. The source was modelled as punctual and was located to 5 cm along the axial axis of the detector. To verify the calculations its were carried out measurements with a spectrometer with a scintillator of 7.62 Φ x 7.62 cm. In the measured spectra the sum peak is observed, while in those calculated it doesn't appear; because the simultaneous detection of photons of different energy doesn't happen each photon since, in single form, it is followed until its complete absorption in the scintillator or when it escapes from the volume of the detector. To reproduce the sum peak and to obtain height spectra of pulses similar to those measured, the sum photons were introduced in the calculations. With the purpose of that Monte Carlo calculation it reproduces the scattering around the photopeak it was used a gaussian function in each photopeak whose characteristics were obtained starting from the experimental data. The calculation of the response of a scintillator allows to establish the capacity of the measurement of the gamma radiation as well as to distinguish the real events of those that appear by the limitations of the detection process. (Author)

  5. Pulse shaping for fast coincidence with NaI(Tl) detectors

    International Nuclear Information System (INIS)

    Bose, S.; Sinha, B.K.; Bhattacharya, R.

    1983-01-01

    The effect of multiple limiting of the anode pulses of the photomultiplier tubes on the resolving time of an NaI(Tl)-NaI(Tl) fast coincidence set up is investigated with the help of a simple transistored limiter circuit. The performance of the set up for different energy ranges selected in the side channels is also investigated. (orig.)

  6. Measurement of radioactive tracer microsphere blood from with NaI(Tl)- and Ge-well type detectors

    International Nuclear Information System (INIS)

    Winkler, B.; Staemmler, G.; Schaper, W.; Frank, J.; Langsdorf, S.

    1982-01-01

    An intrinsic Ge-well type detector was applied for the detection of gamma rays from labeled tracer microspheres. The high energy resolution and the large peak-to-Compton ratio of this spectrometer ensures the application of all available differently labeled tracer microspheres in one experiment. The superior energy resolution of the Ge-detector was documented with the separated photopeak regions of 103-Ru and 85-Sr-labeled tracer microspheres, which result in a single photopeak when an NaI(Tl) detector is used. The Ge-well type detector was compared with an NaI(Tl) spectrometer by counting samples of cardiac muscle in either spectrometer systems. Regression analysis between both spectrometer systems demonstrate identical flow values in these samples for 5 differently labeled tracer microspheres which were administered in 5 dogs. The high sensitivity of the Ge-well-type detector together with a suitable technique for sampling of myocardial tissue accomplishes a high spatial resolution of myocardial perfusion for all available differently labeled tracer microspheres. (orig.)

  7. Composite detector for mixed radiations based on CsI(Tl) and dispersions of small ZnSe(Te) crystals

    International Nuclear Information System (INIS)

    Ryzhikov, V.; Gal'chinetskii, L.; Katrunov, K.; Lisetskaya, E.; Gavriluk, V.; Zelenskaya, O.; Starzhynskiy, N.; Chernikov, V.

    2005-01-01

    A new large area detector of high-energy X-ray and β-radiation has been designed and studied. A composite material based on small-crystalline ZnSe(Te) was applied onto the wide surface of a light guide. An experimental specimen has been prepared, which showed β-sensitivity C β =5.5cm 2 . The spectrograms of a 90 Sr+ 90 Y β-source obtained with the specimen under study make it possible to evaluate the age of the source by the ratio of low- and high-energy regions of the spectrum. The combined detector (CD) comprises a single crystalline plate of ZnSe(Te) placed onto the output window of a scintillating transparent light guide made of CsI(Tl) in the shape of a truncated pyramid. The CsI(Tl) light guide is used to create an additional channel for detection of γ-radiation, as well as for protecting the photodiode from the penetrating radiation. It is shown that introduction of the light guide does not worsen the energy resolution characteristics of ZnSe(Te). Separate detection of α- and γ-radiation has been achieved under simultaneous excitation by 239 Pu (ZnSe(Te), R α =6%) and 241 Am (CsI(Tl), R γ =20%). The use of selective optical filters allows separation of the peaks of total absorption (p.t.a.) in the case of their superposition

  8. Determination of the full energy peak efficiency of NaI(Tl) detectors

    International Nuclear Information System (INIS)

    Cesana, A.; Terrani, M.

    1978-01-01

    A simple procedure for the accurate evaluation of the full energy peak efficiency of NaI(Tl) crystals is described. Particular attention is given to the peak to total ratio determination for which a new method is proposed. (author)

  9. Recent advances in Tl Br, Cd Te and CdZnTe semiconductor radiation detectors: a review

    International Nuclear Information System (INIS)

    Oliveira, Icimone B.

    2011-01-01

    The success in the development of radiation spectrometers operating at room temperature is based on many years of effort on the part of large numbers of workers around the world. These individuals have contributed to the understanding of the fundamental materials issues associated with the growth of semiconductors for this application, the development of device fabrication and processing technology, and advances in low noise electronics and pulse processing. Progress in this field continues at an accelerated pace, as in evidenced by the improvements in detector performance and by the growing number of commercial products. Thus, the last years have been seen continued effort in the development of room temperature compound semiconductors devices. High-Z compound semiconductor detectors has been explored for high energy resolution, high detection efficiency and are of low cost. Compound semiconductors detectors are well suited for addressing needs of demanding applications such as bore hole logging where high operating temperature are encountered. In this work recent developments in semiconductors detectors were reviewed. This review concentrated on thallium bromide (TlBr), cadmium zinc telluride (CdZnTe) and cadmium telluride (CdTe) crystals detectors. TlBr has higher stopping power compared to common semiconductor materials because it has the higher photoelectric and total attenuation coefficients over wide energy range from 100 keV to 1 MeV. CdTe and CdZnTe detectors have several attractive features for detecting X-ray and low energy gamma ray. Their relatively large band gaps lead to a relatively low leakage current and offer an excellent energy resolution at room temperature. A literature survey and bibliography was also included. (author)

  10. Recent advances in Tl Br, Cd Te and CdZnTe semiconductor radiation detectors: a review

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Icimone B. [Universidade Bandeirante (UNIBAN), Sao Paulo, SP (Brazil)

    2011-07-01

    The success in the development of radiation spectrometers operating at room temperature is based on many years of effort on the part of large numbers of workers around the world. These individuals have contributed to the understanding of the fundamental materials issues associated with the growth of semiconductors for this application, the development of device fabrication and processing technology, and advances in low noise electronics and pulse processing. Progress in this field continues at an accelerated pace, as in evidenced by the improvements in detector performance and by the growing number of commercial products. Thus, the last years have been seen continued effort in the development of room temperature compound semiconductors devices. High-Z compound semiconductor detectors has been explored for high energy resolution, high detection efficiency and are of low cost. Compound semiconductors detectors are well suited for addressing needs of demanding applications such as bore hole logging where high operating temperature are encountered. In this work recent developments in semiconductors detectors were reviewed. This review concentrated on thallium bromide (TlBr), cadmium zinc telluride (CdZnTe) and cadmium telluride (CdTe) crystals detectors. TlBr has higher stopping power compared to common semiconductor materials because it has the higher photoelectric and total attenuation coefficients over wide energy range from 100 keV to 1 MeV. CdTe and CdZnTe detectors have several attractive features for detecting X-ray and low energy gamma ray. Their relatively large band gaps lead to a relatively low leakage current and offer an excellent energy resolution at room temperature. A literature survey and bibliography was also included. (author)

  11. A study of the effect of Al2O3 reflector on response function of NaI(Tl) detector

    International Nuclear Information System (INIS)

    Tam, Hoang Duc; Chuong, Huynh Dinh; Thanh, Tran Thien; Van Tao, Chau

    2016-01-01

    This study aims to assess the effect of Al 2 O 3 reflector surrounding the NaI(Tl) crystal on the detector response function, based on Monte Carlo simulation, which can verify the precise model of the NaI(Tl) detector. The method used in determining the suitable thickness of Al 2 O 3 reflector is to compare the calculated and experimental values of full-energy peak efficiency. The results show that the Al 2 O 3 reflector should have a thickness of 0.8–1.2 mm for the maximum deviation between the experimental and simulated efficiency of 3.2% at all concerning energies. In addition, the obtained results are in good agreement with the response function of simulation and experimental spectra. - Highlights: • The study was conducted to verify the model of Monte Carlo simulation. • The effect of Al 2 O 3 reflector on the detector response function was investigated. • The optimum thickness of Al 2 O 3 reflector is suggested.

  12. Scintillation detector composed by new type of avalanche photodiode and CsI(Tl) crystal

    International Nuclear Information System (INIS)

    He Jingtang; Chen Duanbao; Li Zuhao; Mao Yufang; Dong Xiaoli

    1996-01-01

    Using S5345 type of avalanche photodiode produced by Hamamatsu for the CsI(Tl) crystal readout, the spectrum of γ ray were measured. Energy resolution of 6.8% for 1.27 MeV γ ray from 22 Na source was obtained. The relation between energy resolution and coupling area, dimension of crystal, shaping time and bias were measured

  13. Main Achievements 2003-2004 - Interdisciplinary Research - Radiation detection methods for health, earth and environmental sciences - Thermoluminescence (TL) detectors

    International Nuclear Information System (INIS)

    2005-01-01

    The IFJ has over 35 years of experience in the development, production and application of new types of thermoluminescence (TL) detectors, particularly LiF:Mg,Ti and LiF:Mg,Cu,P. Over 600,000 LiF detectors produced at the IFJ PAN are routinely applied in dosimetry services and hospitals in 30 countries. The current research in the field of thermoluminescence concentrates in space dosimetry and novel 2-dimensional detectors for medical applications. The space project (named Matroshka), organized by the European Space Agency, is one of the most ambitious dosimetry experiments in space. In February 2004 an anatomical model of the human body (a humanoid phantom), equipped with over 3500 dedicated thermoluminescent detectors (TLD), developed and produced at IFJ and tested at the Chiba heavy ion accelerator in Japan, was installed outside the International Space Station (ISS) to determine the cosmic radiation doses absorbed in human organs, which would be experienced by astronauts in open space. The phantom will remain in space for one year, after which the detectors will be returned to the IFJ for analysis

  14. Si(Li)-NaI(Tl) sandwich detector array for measurements of trace radionuclides in soil samples

    International Nuclear Information System (INIS)

    Strauss, M.G.; Sherman, I.S.; Roche, C.T.; Pehl, R.H.

    1986-01-01

    An ultra-sensitive X/γ-ray detector system for assaying trace radioactivity in actinide contaminated soil and ash samples has been developed. The new system consists of an array of 6 large Si(Li) X-ray detectors sensitive on both faces and mounted on edge in a paddle-shaped cryostat with a 14 cm diameter Be window on each side. The paddle, with a sample of the soil placed at each window, is sandwiched between 2 large NaI(Tl) scintillators which suppress the γ background. With X-rays being measured simultaneously from soil in 2 sample holders and background reduced by 50% using anticoincidence, the sensitivity of this detector is 4 times higher than that of conventionally mounted Si(Li) detectors. A soil sample containing 50 pCi/g 239 Pu was measured in 5 min with an uncertainty of 1 and NpLsub(β1) X-ray peaks are resolved thus permitting measurement of trace Pu in the presence of 241 Am. This is the most sensitive and selective detector known for nondestructive assay of radioactivity in soil and other samples. (orig.)

  15. Application of the dose conversion factor for a NaI(Tl) detector to the radwaste drum assay

    International Nuclear Information System (INIS)

    Ji, Young-Yong; Hong, Dae-Seok; Kim, Tae-Kuk; Kwak, Kyung-Kil; Ryu, Woo-Seog

    2011-01-01

    The dose-to-curie (DTC) conversion method has been known that there could be extremely high uncertainty associated with establishing the radioactivity of gamma emitters in a drum. However, the DTC conversion method is still an effective assay method to calculate the radioisotope inventory because of the simple and easy procedures to be applied. In order to make the DTC conversion method practical, numerous assumptions and limitations placed on its use. These assumptions and limitations are related to the dose rate measurement and the relative abundance of gamma emitters in a drum. However, these two variables were generally obtained from the different detection mechanisms even using the different radwaste each other. Unfortunately, that expanded the limitation of using the DTC conversion method. In order to obtain two variables in a drum to be assayed at once, the dose conversion factor for a NaI(Tl) detector was first calculated from the MCNP code. The pulse height spectrum from a simulated drum inserted into a standard source was measured by a NaI(Tl) detector, and then, two variables were calculated from the dose conversion factor and the net count rate of detected gamma emitters in the pulse height spectrum.

  16. Deconvolution of gamma energy spectra from NaI (Tl) detector using the Nelder-Mead zero order optimisation method

    International Nuclear Information System (INIS)

    RAVELONJATO, R.H.M.

    2010-01-01

    The aim of this work is to develop a method for gamma ray spectrum deconvolution from NaI(Tl) detector. Deconvolution programs edited with Matlab 7.6 using Nelder-Mead method were developed to determine multiplet shape parameters. The simulation parameters were: centroid distance/FWHM ratio, Signal/Continuum ratio and counting rate. The test using synthetic spectrum was built with 3σ uncertainty. The tests gave suitable results for centroid distance/FWHM ratio≥2, Signal/Continuum ratio ≥2 and counting level 100 counts. The technique was applied to measure the activity of soils and rocks samples from the Anosy region. The rock activity varies from (140±8) Bq.kg -1 to (190±17)Bq.kg -1 for potassium-40; from (343±7)Bq.Kg -1 to (881±6)Bq.kg -1 for thorium-213 and from (100±3)Bq.kg -1 to (164 ±4) Bq.kg -1 for uranium-238. The soil activity varies from (148±1) Bq.kg -1 to (652±31)Bq.kg -1 for potassium-40; from (1100±11)Bq.kg -1 to (5700 ± 40)Bq.kg -1 for thorium-232 and from (190 ±2) Bq.kg -1 to (779 ±15) Bq -1 for uranium -238. Among 11 samples, the activity value discrepancies compared to high resolution HPGe detector varies from 0.62% to 42.86%. The fitting residuals are between -20% and +20%. The Figure of Merit values are around 5%. These results show that the method developed is reliable for such activity range and the convergence is good. So, NaI(Tl) detector combined with deconvolution method developed may replace HPGe detector within an acceptable limit, if the identification of each nuclides in the radioactive series is not required [fr

  17. Automatic measurement for solid state track detectors

    International Nuclear Information System (INIS)

    Ogura, Koichi

    1982-01-01

    Since in solid state track detectors, their tracks are measured with a microscope, observers are forced to do hard works that consume time and labour. This causes to obtain poor statistic accuracy or to produce personal error. Therefore, many researches have been done to aim at simplifying and automating track measurement. There are two categories in automating the measurement: simple counting of the number of tracks and the requirements to know geometrical elements such as the size of tracks or their coordinates as well as the number of tracks. The former is called automatic counting and the latter automatic analysis. The method to generally evaluate the number of tracks in automatic counting is the estimation of the total number of tracks in the total detector area or in a field of view of a microscope. It is suitable for counting when the track density is higher. The method to count tracks one by one includes the spark counting and the scanning microdensitometer. Automatic analysis includes video image analysis in which the high quality images obtained with a high resolution video camera are processed with a micro-computer, and the tracks are automatically recognized and measured by feature extraction. This method is described in detail. In many kinds of automatic measurements reported so far, frequently used ones are ''spark counting'' and ''video image analysis''. (Wakatsuki, Y.)

  18. Gamma camera system with composite solid state detector

    International Nuclear Information System (INIS)

    Gerber, M.S.; Miller, D.W.

    1977-01-01

    A composite solid-state detector is described for utilization within gamma cameras. The detector's formed of an array of detector crystals, the opposed surfaces of each of which are formed incorporating an impedance-derived configuration for determining one coordinate of the location of discrete impinging photons upon the detector. A combined read-out for all detectors within the composite array is achieved through a row and column interconnection of the impedance configurations. Utilizing the read-outs for respective sides of the discrete crystals, a resultant time-constant characteristic for the composite detector crystal array remains essentially that of individual crystal detectors

  19. The solid state detector technology for picosecond laser ranging

    Science.gov (United States)

    Prochazka, Ivan

    1993-01-01

    We developed an all solid state laser ranging detector technology, which makes the goal of millimeter accuracy achievable. Our design and construction philosophy is to combine the techniques of single photon ranging, ultrashort laser pulses, and fast fixed threshold discrimination while avoiding any analog signal processing within the laser ranging chain. The all solid state laser ranging detector package consists of the START detector and the STOP solid state photon counting module. Both the detectors are working in an optically triggered avalanche switching regime. The optical signal is triggering an avalanche current buildup which results in the generation of a uniform, fast risetime output pulse.

  20. NaI(Tl) scintillator detectors stripping procedure for air kerma measurements of diagnostic X-ray beams

    Science.gov (United States)

    Oliveira, L. S. R.; Conti, C. C.; Amorim, A. S.; Balthar, M. C. V.

    2013-03-01

    Air kerma is an essential quantity for the calibration of national standards used in diagnostic radiology and the measurement of operating parameters used in radiation protection. Its measurement within the appropriate limits of accuracy, uncertainty and reproducibility is important for the characterization and control of the radiation field for the dosimetry of the patients submitted to diagnostic radiology and, also, for the assessment of the system which produces radiological images. Only the incident beam must be considered for the calculation of the air kerma. Therefore, for energy spectrum, counts apart the total energy deposition in the detector must be subtracted. It is necessary to establish a procedure to sort out the different contributions to the original spectrum and remove the counts representing scattered photons in the detector's materials, partial energy deposition due to the interactions in the detector active volume and, also, the escape peaks contributions. The main goal of this work is to present spectrum stripping procedure, using the MCNP Monte Carlo computer code, for NaI(Tl) scintillation detectors to calculate the air kerma due to an X-ray beam usually used in medical radiology. The comparison between the spectrum before stripping procedure against the reference value showed a discrepancy of more than 63%, while the comparison with the same spectrum after the stripping procedure showed a discrepancy of less than 0.2%.

  1. Developments of directional detectors with NaI(Tl)/BGO scintillators

    International Nuclear Information System (INIS)

    Shirakawa, Y.

    2004-01-01

    This paper describes directional gamma ray detectors with different types of scintillators. The detectors, which positively increase directional sensitivity to incident gamma rays, have been developed to measure directions, energies and counts of gamma rays, and to search for radioactive materials such as orphan radioisotopes or contaminations. Experimental results have shown that proposed directional detectors have a potential for practical use in real fields and will contribute to radiation protection and safety

  2. Application of NaI(Tl) scintillation detector to measurement of tritium concentration

    International Nuclear Information System (INIS)

    Nishizawa, Kazushige; Endo, Yoshio; Shinagawa, Mutsuaki

    1977-01-01

    Measurements of tritium concentration in various media have been successfully performed by detecting with an ordinary NaI(Tl) scintillation counter the bremsstrahlung emitted from tritium decay. To distinguish meaningful signals from noises emanating mainly from thermoelectrons present in the phototube, differences in rise time were discriminated by means of an electronic circuit, instead of separation by pulse height analysis. This pulse-shape discriminator successfully reduced noise counts below 18 keV in a multichannel analyzer from 100 cpm to 4 cpm, which permitted direct counting of tritiated water as dilute as 1 μCi/ml, without requiring any complicated preparation. (auth.)

  3. NaI(Tl) scintillator detectors stripping procedure for air kerma measurements of diagnostic X-ray beams

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, L.S.R. [Centro Tecnológico do Exército, CTEx (Brazilian Army Technological Center), Av. das Américas n° 28705, 23085-470 Rio de Janeiro (Brazil); Instituto de Radioprotecão e Dosimetria, CNEN/IRD (Institute for Radioprotection and Dosimetry, CNEN/IRD), Av. Salvador Allende s/no, P.O. Box 37750, 22783-127 Barra da Tijuca, Rio de Janeiro (Brazil); Conti, C.C., E-mail: ccconti@ird.gov.br [Instituto de Radioprotecão e Dosimetria, CNEN/IRD (Institute for Radioprotection and Dosimetry, CNEN/IRD), Av. Salvador Allende s/no, P.O. Box 37750, 22783-127 Barra da Tijuca, Rio de Janeiro (Brazil); Amorim, A.S.; Balthar, M.C.V. [Centro Tecnológico do Exército, CTEx (Brazilian Army Technological Center), Av. das Américas n° 28705, 23085-470 Rio de Janeiro (Brazil)

    2013-03-21

    Air kerma is an essential quantity for the calibration of national standards used in diagnostic radiology and the measurement of operating parameters used in radiation protection. Its measurement within the appropriate limits of accuracy, uncertainty and reproducibility is important for the characterization and control of the radiation field for the dosimetry of the patients submitted to diagnostic radiology and, also, for the assessment of the system which produces radiological images. Only the incident beam must be considered for the calculation of the air kerma. Therefore, for energy spectrum, counts apart the total energy deposition in the detector must be subtracted. It is necessary to establish a procedure to sort out the different contributions to the original spectrum and remove the counts representing scattered photons in the detector’s materials, partial energy deposition due to the interactions in the detector active volume and, also, the escape peaks contributions. The main goal of this work is to present spectrum stripping procedure, using the MCNP Monte Carlo computer code, for NaI(Tl) scintillation detectors to calculate the air kerma due to an X-ray beam usually used in medical radiology. The comparison between the spectrum before stripping procedure against the reference value showed a discrepancy of more than 63%, while the comparison with the same spectrum after the stripping procedure showed a discrepancy of less than 0.2%.

  4. Experimental response function of NaI(Tl) scintillation detector for gamma photons and tomographic measurements for defect detection

    International Nuclear Information System (INIS)

    Sharma, Amandeep; Singh, Karamjit; Singh, Bhajan; Sandhu, B.S.

    2011-01-01

    The response function of gamma detector is an important factor for spectrum analysis because some photons and secondary electrons may escape the detector volume before fully depositing their energy, of course destroys the ideal delta function response. An inverse matrix approach, for unfolding of observed pulse-height distribution to a true photon spectrum, is used for construction of experimental response function by formulating a 40 x 40 matrix with bin mesh (E 1/2 ) of 0.025 (MeV) 1/2 for the present measurements. A tomographic scanner system, operating in a non-destructive and non-invasive way, is also presented for inspection of density variation in any object. The incoherent scattered intensity of 662 keV gamma photons, obtained by unfolding (deconvolution) the experimental pulse-height distribution of NaI(Tl) scintillation detector, provides the desired information. The method is quite sensitive, for showing inclusion of medium Z (atomic number) material (iron) in low Z material (aluminium) and detecting a void of ∼2 mm in size for iron block, to investigate the inhomogeneities in the object. Also, the grey scale images (using 'MATLAB') are shown to visualise the presence of defects/inclusion in metal samples.

  5. Search for solar axions with CsI(Tl) crystal detectors

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Y.S. [Center for Underground Physics, Institute for Basic Science (IBS), Daejon 34047 (Korea, Republic of); Park, H.K. [Center for Underground Physics, Institute for Basic Science (IBS), Daejon 34047 (Korea, Republic of); Basic Science, IBS-UST School, Daejeon 34047 (Korea, Republic of); Bhang, H.; Choi, J.H. [Department of Physics and Astronomy, Seoul National University, Seoul 08826 (Korea, Republic of); Collaboration: The KIMS collaboration

    2016-06-01

    The results of a search for solar axions from the Korea Invisible Mass Search (KIMS) experiment at the Yangyang Underground Laboratory are presented. Low-energy electron-recoil events would be produced by conversion of solar axions into electrons via the axio-electric effect in CsI(Tl) crystals. Using data from an exposure of 34,596 kg⋅days, we set a 90 % confidence level upper limit on the axion-electron coupling, g{sub ae}, of 1.39×10{sup −11} for an axion mass less than 1 keV/c{sup 2}. This limit is lower than the indirect solar neutrino bound, and fully excludes QCD axions heavier than 0.48 eV/c{sup 2} and 140.9 eV/c{sup 2} for the DFSZ and KSVZ models respectively.

  6. Calculation of total counting efficiency of a NaI(Tl) detector by hybrid Monte-Carlo method for point and disk sources

    Energy Technology Data Exchange (ETDEWEB)

    Yalcin, S. [Education Faculty, Kastamonu University, 37200 Kastamonu (Turkey)], E-mail: yalcin@gazi.edu.tr; Gurler, O.; Kaynak, G. [Department of Physics, Faculty of Arts and Sciences, Uludag University, Gorukle Campus, 16059 Bursa (Turkey); Gundogdu, O. [Department of Physics, School of Engineering and Physical Sciences, University of Surrey, Guildford GU2 7XH (United Kingdom)

    2007-10-15

    This paper presents results on the total gamma counting efficiency of a NaI(Tl) detector from point and disk sources. The directions of photons emitted from the source were determined by Monte-Carlo techniques and the photon path lengths in the detector were determined by analytic equations depending on photon directions. This is called the hybrid Monte-Carlo method where analytical expressions are incorporated into the Monte-Carlo simulations. A major advantage of this technique is the short computation time compared to other techniques on similar computational platforms. Another advantage is the flexibility for inputting detector-related parameters (such as source-detector distance, detector radius, source radius, detector linear attenuation coefficient) into the algorithm developed, thus making it an easy and flexible method to apply to other detector systems and configurations. The results of the total counting efficiency model put forward for point and disc sources were compared with the previous work reported in the literature.

  7. Calculation of total counting efficiency of a NaI(Tl) detector by hybrid Monte-Carlo method for point and disk sources

    International Nuclear Information System (INIS)

    Yalcin, S.; Gurler, O.; Kaynak, G.; Gundogdu, O.

    2007-01-01

    This paper presents results on the total gamma counting efficiency of a NaI(Tl) detector from point and disk sources. The directions of photons emitted from the source were determined by Monte-Carlo techniques and the photon path lengths in the detector were determined by analytic equations depending on photon directions. This is called the hybrid Monte-Carlo method where analytical expressions are incorporated into the Monte-Carlo simulations. A major advantage of this technique is the short computation time compared to other techniques on similar computational platforms. Another advantage is the flexibility for inputting detector-related parameters (such as source-detector distance, detector radius, source radius, detector linear attenuation coefficient) into the algorithm developed, thus making it an easy and flexible method to apply to other detector systems and configurations. The results of the total counting efficiency model put forward for point and disc sources were compared with the previous work reported in the literature

  8. Recommendations for the measurement 131I in human thyroid using a detector of NaI(Tl)

    International Nuclear Information System (INIS)

    Puerta Yepes, N.; Rojo, A.M.; Andres, P.A.

    2010-01-01

    The Argentine Total Body Counter Laboratory of the Nuclear Regulatory Authority participated in the last regional intercomparison Exercise organized in the frame of the IAEA Project RLA 9/066 related with in vivo measurements of 131 I in the thyroid. There were identified some difficulties in determining the efficiency and calibration factor (CF) for the 131 I when a source of 133 Ba and a detector of NaI (Tl) are used in the calibration process. Independent measurements were performed for two calibration sources of known activity ( 133 Ba and 131 I) with identical geometry pattern and using a gamma spectrometry system with NaI(Ti) detector. It was found that the region of interest (ROI) which, both in the spectrum of 133 Ba as in the spectrum of 131 I, had the same efficiency. It was determined the activity of the source of 133 Ba , distributed in the intercomparison, and the calibrated source of 131 I using different values of efficiency and FC obtained. It was analyzed the conditions under which the use of 133 Ba as a source of calibration is effective for the measurement of 131 I. (authors) [es

  9. On the Mechanisms of Formation of Memory Channels and Development of Negative Differential Resistance in Solid Solutions of the TlInTe2-TlYbTe2 System

    Science.gov (United States)

    Akhmedova, A. M.

    2018-04-01

    The behavior of an electronic subsystem is investigated in the course of formation and development of a memory channel in solid solutions of the TlInTe2-TlYbTe2 system. An analysis of the current-voltage characteristics allows getting an insight into the reason for a sharp change in electrical conductance of the specimens under study during their transition from the high-resistance to high-conductance state and the reasons for the well known instability of threshold converters, which makes it possible to design devices with high threshold voltage stability.

  10. Comparison of multi-pole shaping and delay line clipping pre-amplifiers for position sensitive NaI(Tl) detectors

    International Nuclear Information System (INIS)

    Freifelder, R.; Karp, J.S.; Wear, J.A.; Lockyer, N.S.; Newcomer, F.M.; Surti, S.; Berg, R. van

    1998-01-01

    NaI(Tl) position sensitive detectors have been used in medical imaging for many years. For PET applications without collimators, the high counting rates place severe demands on such large area detectors. The NaI(Tl) detectors in the PENN-PET scanners are read-out via photomultiplier tubes and preamplifiers. Those preamplifiers use a delay-line clipping technique to shorten the characteristic 240 ns fall time of the NaI(Tl) signal. As an alternative, the authors have investigated a pole-zero network to shorten the signal followed by a multi-pole shaper to produce a symmetric signal suitable for high counting rates. This has been compared to the current design by measuring the energy and spatial resolution of a single detector as a function of different preamplifier designs. Data were taken over a range of ADC integration times and countrates. The new design shows improved energy resolution with short integration times. Effects on spatial resolution and deadtime are reported for large position sensitive detectors at different countrates

  11. Solid-state radiation detectors technology and applications

    CERN Document Server

    2015-01-01

    The book discusses the current solid state material used in advance detectors manufacturing and their pros and cons and how one can tailor them using different techniques, to get the maximum performance. The book is application oriented to radiation detectors for medical, X and gamma rays application, and good reference with in-depth discussion of detector's physics as it relates to medical application tailored for engineers and scientists.

  12. Dependence of NaI(Tl) detector intrinsic efficiency on source ...

    Indian Academy of Sciences (India)

    on source–detector distance, energy and off-axis distance: Their ... This d/R value at which minimum efficiency occurs approaches zero as off- axis distance ... It should be noted at this point that from the point of view of radiation protection ...

  13. Response functions of NaI(Tl) detectors to terrestrial gamma radiation

    International Nuclear Information System (INIS)

    Gyurcsak, J.; Lenda, A.

    1978-01-01

    Computer programs, serving for calculation of detector efficiency and energy deposition spectrum for scintillation crystals irradiated by isotropic or half-isotropic gamma-ray fields were elaborated. The Monte-Carlo models used in calculations are valid for gamma-ray energies 2 π geometry by the 1.5'' x 2'' probe with experimental results is given. (author)

  14. Solid-state cadmium telluride radiation detector

    Energy Technology Data Exchange (ETDEWEB)

    Takeuchi, Yoji; Kitamoto, Hisashi; Hosomatsu, Haruo

    1984-09-01

    The growth of CdTe single crystal and its application to CdTe detector array was studied for X-ray computed tomography (XCT) equipment. A p-type CdTe single crystal with 10/sup 4/ ohm.cm specific resistivity was grown in a quartz ampoule under vapor pressure control of Cd in a vertical Bridgman furnace. An 18-element detector array was fabricated with this single crystal. The detector was operated with no bias and the sensitivity was confirmed to be between 2.8 x 10/sup -12/ and 14 x 10/sup -12/ A.h/(R.mm/sup 2/). Commercial CdTe single crystal was used to manufacture as 560-element detector array for XCT. Results show that CdTe detector is sensitive, linear and has high resolution.

  15. Solid state detectors for neutron radiation monitoring in fusion facilities

    International Nuclear Information System (INIS)

    Gómez-Ros, J.M.

    2014-01-01

    The purpose of this communication is to summarize the main solid state based detectors proposed for neutron diagnostic in fusion applications and their applicability under the required harsh conditions in terms of intense radiation, high temperature and available space restrictions. Activation systems, semiconductor based detectors, luminescent materials and Cerenkov fibre optics sensors (C-FOS) are the main devices that are described. - Highlights: • A state-of-the-art summary of solid state based detectors are described. • Conditions and restrictions for their applicability are described. • A list of the 38 more relevant references has been included

  16. A large solid angle multiparameter neutron detector

    International Nuclear Information System (INIS)

    Ricco, G.; Anghinolfi, M.; Corvisiero, P.; Durante, E.; Maggiolo, S.; Prati, P.; Rottura, A.; Taiuti, M.

    1991-01-01

    A 4π neutron detector has been realized using organic scintillators: the detector is suitable for high efficiency, low background measurements of very low neutron rates in the 0.6-5 MeV energy range. Gamma-neutron discrimination has been performed by pulse shape, energy and neutron lifetime analysis and backgrounds have been reduced by anticoincidence detectors and paraffin-lead shielding. Tests of efficiency, energy resolution and radiation identification have been made with a low intensity Am-Be neutron source. (orig.)

  17. Towards the use of small amounts of activated charcoal along with well-type NaI(Tl) detector for indoor radon measurements

    International Nuclear Information System (INIS)

    Al-Azmi, D.

    2006-01-01

    The feasibility of using small quantities of activated charcoal and a 7.6 cm x 7.6 cm NaI(Tl) well-type detector was investigated for indoor radon measurements. Vials, filled with 10 g of charcoal, were exposed for different indoor radon concentration levels typical of Kuwait dwellings. After exposure, the vials were sealed and kept for 3 h to allow radon to come into radioactive equilibrium with its progenies and were then analysed by gamma-ray spectrometry using the well-type NaI(Tl) detector. The variation of radon absorption by the vials filled with charcoal with exposure time was also studied. A comparative study of the present technique with the standard technique of using 70 g charcoal canisters and flat NaI detector was also performed. After establishing the suitability of the technique, the charcoal vials were then used to investigate the effect of air-ventilation on the concentration levels of the indoor radon. Results show that there is a reduction in the radon concentration level (up to 25%) when the air-ventilation system was switched on. The paper presents the results of the study on the feasibility of combining small amounts of activated charcoal with a well-type NaI(Tl) detector in the measurement of indoor radon concentrations. (authors)

  18. Performance Characteristic of a CsI(Tl) Flat Panel Detector Radiography System

    International Nuclear Information System (INIS)

    Jeong, Hoi Woun; Min, Jung Hwan; Kim, Jung Min; Park, Min Seok; Lee, Gaung Young

    2012-01-01

    The purpose of this work was to evaluate an amorphous silicon cesium iodide based indirect flat-panel detector (FPD) in terms of their modulation transfer function (MTF), Wiener spectrum (WS, or noise power spectrum, NPS), and detective quantum efficiency (DQE). Measurements were made on flat-panel detector using the International Electrotechnical Commission (IEC) defined RQA3, RQA5, RQA7, and RQA9 radiographic technique. The MTFs of the systems were measured using an edge method. The WS(NPS) of the systems were determined for a range of exposure levels by two-dimensional (2D). Fourier analysis of uniformly exposed radiographs. The DQEs were assessed from the measured MTF, WS(NPS), exposure, and estimated ideal signal-to-noise ratios. Characteristic curve in the RQA3 showed difference in the characteristic curve from RQA5, RQA7, RQA9. MTFs were not differences according to x-ray beam quality. WS(NPS) was reduced with increasing dose, and RQA 3, RQA5, RQA7, RQA9 as the order is reduced. DQE represented the best in the 1mR, RQA 3, RQA5, RQA7, RQA9 decrease in the order. The physical imaging characteristics of FPD may also differ from input beam quality. This study gives an initial motivation that the physical imaging characteristics of FPD is an important issue for the right use of digital radiography system.

  19. Performance Characteristic of a CsI(Tl) Flat Panel Detector Radiography System

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Hoi Woun [Dept. of Radiological Science, Baekseok Culture University, Seoul (Korea, Republic of); Min, Jung Hwan [Dept. of Radiological Technology, Shingu University, Seongnam (Korea, Republic of); Kim, Jung Min [Dept. of Radiological Science, Korea University, Health Science College, Seoul (Korea, Republic of); Park, Min Seok [Korea Institue of Radiological and Medical Sicences, Research Institute of Radiologycal and Medical Sciences, Seoul (Korea, Republic of); Lee, Gaung Young [National Institute of Food and Drug Safety Evaluation, Seoul (Korea, Republic of)

    2012-06-15

    The purpose of this work was to evaluate an amorphous silicon cesium iodide based indirect flat-panel detector (FPD) in terms of their modulation transfer function (MTF), Wiener spectrum (WS, or noise power spectrum, NPS), and detective quantum efficiency (DQE). Measurements were made on flat-panel detector using the International Electrotechnical Commission (IEC) defined RQA3, RQA5, RQA7, and RQA9 radiographic technique. The MTFs of the systems were measured using an edge method. The WS(NPS) of the systems were determined for a range of exposure levels by two-dimensional (2D). Fourier analysis of uniformly exposed radiographs. The DQEs were assessed from the measured MTF, WS(NPS), exposure, and estimated ideal signal-to-noise ratios. Characteristic curve in the RQA3 showed difference in the characteristic curve from RQA5, RQA7, RQA9. MTFs were not differences according to x-ray beam quality. WS(NPS) was reduced with increasing dose, and RQA 3, RQA5, RQA7, RQA9 as the order is reduced. DQE represented the best in the 1mR, RQA 3, RQA5, RQA7, RQA9 decrease in the order. The physical imaging characteristics of FPD may also differ from input beam quality. This study gives an initial motivation that the physical imaging characteristics of FPD is an important issue for the right use of digital radiography system.

  20. Radioactive flow detectors: liquid or solid scintillators

    International Nuclear Information System (INIS)

    Reich, A.R.

    1983-01-01

    During the past five years, two schools of thought have emerged producing two different types of radio-HPLC detectors. Based on the naphthalene-in-the-vial principle, manufacturers have developed heterogeneous scintillation detectors. In these detectors the anthracene or naphthalene crystals are replaced by other scintillators. In order to avoid dead space and turbulence, a narrow diameter tube is used, either straight, or more popularly formed into a coil or a 'U' as the cell. To optimize light transmission to the photomultiplier tubes, mirrors are used. Due to limiting factors in this technique the counting efficiency for tritium is below the 10 percent level. The other school of radio-HPLC detectors based their design on classical liquid scintillation counting technology. In a homogeneous detector, the effluent from the HPLC system is mixed with a suitable liquid scintillator before entering the counting cell. The cell design is typically a flat glass or Teflon coil tightly sandwiched between two photomultiplier tubes, making good optical contact without the use of mirrors. Depending on the chromatographic effluent, 3 H efficiencies between 25 to 50 percent, and 14 C counting efficiencies up to 85 percent can be achieved

  1. X-ray diffraction studies of the Tl(GaS{sub 2}){sub 1–x}(InSe{sub 2}){sub x} solid solutions

    Energy Technology Data Exchange (ETDEWEB)

    Sheleg, A. U.; Hurtavy, V. G., E-mail: hurtavy@physics.by; Chumak, V. A. [National Academy of Sciences of Belarus, Scientific-Practical Materials Research Center (Belarus); Mustafaeva, S. N.; Kerimova, E. M. [Azerbaijan National Academy of Sciences, Institute of Physics (Azerbaijan)

    2016-07-15

    The unit-cell parameters of crystals obtained in the Tl(GaS{sub 2}){sub 1–x}(InSe{sub 2}){sub x} system are measured by X-ray diffraction. The relationship between these parameters and composition is determined. It is shown that, with growing x, the a, b, and c parameters increase and the β angle decreases. Two types of solid solutions are found in the Tl(GaS{sub 2}){sub 1–x}(InSe{sub 2}){sub x} system: one is based on compound TlGaS{sub 2} with monoclinic structure and the other is based on TlInSe{sub 2} with tetragonal structure.

  2. Particle gamma correlations in {sup 12}C measured with the CsI(Tl) based detector array CHIMERA

    Energy Technology Data Exchange (ETDEWEB)

    Cardella, G., E-mail: cardella@ct.infn.it [INFN - Sezione di Catania, Via S. Sofia, 95123 Catania (Italy); Acosta, L. [INFN - Sezione di Catania, Via S. Sofia, 95123 Catania (Italy); Amorini, F. [INFN - Laboratori Nazionali del Sud, Via S. Sofia, Catania (Italy); Auditore, L. [INFN Gruppo collegato di Messina and Dip. di Fisica e Scienze della Terra, Università di Messina (Italy); Berceanu, I. [Institute for Physics and Nuclear Engineering, Bucharest (Romania); Castoldi, A. [INFN Sezione di Milano e Politecnico Milano (Italy); De Filippo, E. [INFN - Sezione di Catania, Via S. Sofia, 95123 Catania (Italy); Dell' Aquila, D. [Dipartimento di scienze Fisiche, Università Federico II and INFN Sezione di Napoli (Italy); Francalanza, L. [INFN - Laboratori Nazionali del Sud, Via S. Sofia, Catania (Italy); Dip. di Fisica e Astronomia, Università di Catania, Via S. Sofia, Catania (Italy); Gnoffo, B. [INFN - Sezione di Catania, Via S. Sofia, 95123 Catania (Italy); Guazzoni, C. [INFN Sezione di Milano e Politecnico Milano (Italy); Lanzalone, G. [INFN - Laboratori Nazionali del Sud, Via S. Sofia, Catania (Italy); Facoltà di Ingegneria e Architettura, Università Kore, Enna (Italy); Lombardo, I. [Dipartimento di scienze Fisiche, Università Federico II and INFN Sezione di Napoli (Italy); Minniti, T.; Morgana, E.; Norella, S. [INFN Gruppo collegato di Messina and Dip. di Fisica e Scienze della Terra, Università di Messina (Italy); Pagano, A. [INFN - Sezione di Catania, Via S. Sofia, 95123 Catania (Italy); Pagano, E.V. [INFN - Laboratori Nazionali del Sud, Via S. Sofia, Catania (Italy); Dip. di Fisica e Astronomia, Università di Catania, Via S. Sofia, Catania (Italy); Papa, M.; Pirrone, S. [INFN - Sezione di Catania, Via S. Sofia, 95123 Catania (Italy); and others

    2015-11-01

    The gamma decay of the first excited 4.44 MeV 2+level of {sup 12}C, populated by inelastic scattering of proton and {sup 16}O beams at various energies was studied in order to test γ-ray detection efficiency and the quality of angular distribution information given by the CsI(Tl) detectors of the 4π CHIMERA array. The γ-decay was measured in coincidence with ejectile scattered particles in an approximately 4π geometry allowing to extract the angular distribution in the reference frame of recoiling {sup 12}C target. The typical sin{sup 2} (2θ) behavior of angular distribution was observed in the case of {sup 16}O beam. Besides that, for the proton beam, in order to explain the observed distribution, the addition of an incoherent flat contribution was required. This latter is the effect of proton spin flip events allowing the population of M=±1 magnetic substates, that is not possible in reactions induced by {sup 16}O beam. A comparison with previously collected data, obtained measuring only in and out of plane proton-γ-ray coincidences, confirms the good quality of the angular distribution information given by the apparatus. Possible applications with radioactive beams are outlined.

  3. Study by Monte Carlo methods of an explosive detection system using a D-D generator and Nal (Tl) detectors

    International Nuclear Information System (INIS)

    Cevallos R, L. E.; Guzman G, K. A.; Gallego, E.; Garcia F, G.; Vega C, H. R.

    2017-10-01

    The detection of hidden explosive material is very important for national security. Using Monte Carlo methods, with the code MCNP6, several proposed configurations of a detection system with a Deuterium-Deuterium (D-D) generator, in conjunction with NaI (Tl) scintillation detectors, have been evaluated to intercept hidden explosives. The response of the system to various explosive samples such as Rdx and ammonium nitrate are analyzed as the main components of home-military explosives. The D-D generator produces fast neutrons of 2.5 MeV in a maximum field of 10 10 n/s (Dd-110) which is surrounded with high density polyethylene in order to thermalized the fast neutrons making them interact with the sample inspected, giving rise to the emission of gamma rays that generates a characteristic spectrum of the elements that constitute it, being able in this way to determine its chemical composition and identify the type of substance. The necessary shielding is evaluated to estimate the admissible operation dose, with thicknesses of lead and borated polyethylene, in order to place it at some point of the Laboratory of Neutron Measurements of the Polytechnic University of Madrid where the shielding is optimal. The results show that its functionality is promising in the field of national security for the explosives inspection. (Author)

  4. Developments in solid state vertex detectors

    International Nuclear Information System (INIS)

    Damerell, C.J.S.

    1984-12-01

    Since the discovery of the J/psi in November 1974, there has been a strong interest in the physics of particles containing higher-flavour quarks (charm, bottom, top, ...). High precision vertex detectors can be used to identify the decay products of parent particles which have lifetimes of the order 10 -13 s. The paper surveys the progress which is being made in developing silicon detectors with the necessary tracking precision (< approx. 5 μm) to be used for this purpose in fixed target experiments and also in colliders such as SLC and LEP. (author)

  5. Collisions of neutrons and of gamma rays in Bi4Ge3O12 (BGO) and NaI(Tl) scintillation detectors

    International Nuclear Information System (INIS)

    Kushneriuk, S.A.; Lone, M.A.; Hausser, O.; Wong, P.Y.

    1983-06-01

    The role of collision/escape probabilities in establishing the prompt response of bismuth germanate and NaI(Tl) scintillators is investigated. A possible approximation to the collision probability is discussed. Exact expressions for the probability of escape of radiation from finite, right circular cylindrical and rectangular parallelepiped-shaped detectors are derived from an exponential-like spatial distribution of the source in the detector medium and a parametrized angular distribution of emission of the source. Fairly extensive tables of collision probabilities calculated for these bodies are given. For purposes of comparison some results obtained previously in a Monte Carlo calculation are also presented and discussed

  6. TL detectors for gamma-ray dose measurements in critically accidents

    International Nuclear Information System (INIS)

    Miljanic, S.; Knezevic, Z.; Zorko, B.; Gregori, B.

    2005-01-01

    Full text: Determination of gamma-ray dose in mixed neutron + gamma-ray fields is still a challenging task. Dosemeters used for gamma-ray dosimetry are usually in some extent sensitive to neutrons and their response variations depend on neutron energy i.e. on neutron spectra. Besides, it is necessary to take into account the energy dependence of dosimeter responses to gamma-rays. To reduce all these influences, design of dosemeter holders is of special importance. In this work, several types of thermoluminescent detectors (TLD) placed in different holders used for gamma-ray dose determination in mixed fields were examined. Dosemeters were from three different institutions: Ruder Boscovic Institute (RBI), Croatia, Jozef Stefan Institute (JSI), Slovenia and Autoridad Regulatoria Nuclear (ARN), Argentina. All dosemeters were irradiated during the International Intercomparison of Criticality Accident Dosimetry Systems at the SILENE Reactor, Valduc, June 2002. At that exercise three accidental scenarios were reproduced: bare reactor, free evolution; lead shielded reactor, steady state; and lead shielded reactor, free evolution. In each irradiation dosemeters were exposed placed on the front of phantom and 'free-in-air'. Also, dosemeters were irradiated in a pure gamma ray field of 60 Co source. Following types of TLDs were used: 7 LiF (TLD-700), CaF 2 :Mn and AI 2 O 3 :Mg,Y - all from RBI; CaF 2 :Mn from JSI and 7 LiF (TLD-700) from ARN. Reported doses were compared with the reference values as well as with the mean participants' values. The results show satisfactory agreement with other dosimetry systems used in the Intercomparison. The influence of different types of holders and applied corrections of dosemeters' readings are discussed. (author)

  7. Criticality monitoring with digital systems and solid state neutron detectors

    International Nuclear Information System (INIS)

    Willhoite, S.B.

    1984-01-01

    A commercially available system for criticality monitoring combines the well established technology of digital radiation monitoring with state-of-the art detector systems capable of detecting criticality excursions of varying length and intensity with a high degree of confidence. The field microcomputer servicing the detector clusters contains hardware and software to acquire detector information in both the digital count rate and bit sensing modes supported by the criticality detectors. In both cases special criticality logic in the field microcomputer is used to determine the validity of the criticality event. The solid-state neutron detector consists of a 6 LiF wafer coupled to a diffused-junction charged particle detector. Alpha particles resulting from (n,α) interactions within the lithium wafer produce a pulsed signal corresponding to neutron intensity. Special detector circuitry causes the setting of a criticality bit recognizable by the microcomputer should neutron field intensities either exceed a hardware selectable frequency or saturate the detector resulting in a high current condition. These two modes of criticality sensing, in combination with the standard method of comparing an operator selectable alarm setpoint with the detector count rate, results in a criticality system capable of effective operation under the most demanding criticality monitoring conditions

  8. Solid state semiconductor detectorized survey meter

    International Nuclear Information System (INIS)

    Okamoto, Eisuke; Nagase, Yoshiyuki; Furuhashi, Masato

    1987-01-01

    Survey meters are used for measurement of gamma ray dose rate of the space and the surface contamination dencity that the atomic energy plant and the radiation facility etc. We have recently developed semiconductor type survey meter (Commercial name: Compact Survey Meter). This survey meter is a small-sized dose rate meter with excellent function. The special features are using semiconductor type detector which we have developed by our own technique, stablar wide range than the old type, long life, and easy to carry. Now we introduce the efficiency and the function of the survey meter. (author)

  9. The neutron diffraction of molten TlCl, TlBr, and TlI

    International Nuclear Information System (INIS)

    Satow, T.; Uemura, O.; Hoshino, K.; Watanabe, T.

    1984-01-01

    Structure factors S(K) for liquid TlCl, TlBr, and TlI are determined by neutron diffraction measurements. Atomic radial distribution functions (RDF) derived from S(K) are presented. All RDF values are slightly smaller than those of their solid state counter parts. Results show that TlX has a tendency not to retain cesium-chloride type local order, but to take sodium-chloride type order when melting

  10. A New Approach for the Determination of Dose Rate and Radioactivity for Detected Gamma Nuclides Using an Environmental Radiation Monitor Based on an NaI(Tl) Detector.

    Science.gov (United States)

    Ji, Young-Yong; Kim, Chang-Jong; Lim, Kyo-Sun; Lee, Wanno; Chang, Hyon-Sock; Chung, Kun Ho

    2017-10-01

    To expand the application of dose rate spectroscopy to the environment, the method using an environmental radiation monitor (ERM) based on a 3' × 3' NaI(Tl) detector was used to perform real-time monitoring of the dose rate and radioactivity for detected gamma nuclides in the ground around an ERM. Full-energy absorption peaks in the energy spectrum for dose rate were first identified to calculate the individual dose rates of Bi, Ac, Tl, and K distributed in the ground through interference correction because of the finite energy resolution of the NaI(Tl) detector used in an ERM. The radioactivity of the four natural radionuclides was then calculated from the in situ calibration factor-that is, the dose rate per unit curie-of the used ERM for the geometry of the ground in infinite half-space, which was theoretically estimated by Monte Carlo simulation. By an intercomparison using a portable HPGe and samples taken from the ground around an ERM, this method to calculate the dose rate and radioactivity of four nuclides using an ERM was experimentally verified and finally applied to remotely monitor them in real-time in the area in which the ERM had been installed.

  11. Some aspects of solid track detector usage in ecological research

    International Nuclear Information System (INIS)

    Berzina, I.G.; Gusev, E.B.; Ivanov, V.A.

    1991-01-01

    The ability of plants to accumulate large quantities of uranium in areas with unfavorable environmental conditions caused by the open working of various deposits and the mining of uranium containing minerals is discussed. The experimental data show the need for qualitative and quantitative revisions of radiation safety levels. Aspects of the use of solid state track detectors in this research are presented. (author)

  12. Laser solid sampling for a solid-state-detector ICP emission spectrometer

    International Nuclear Information System (INIS)

    Noelte, J.; Moenke-Blankenburg, L.; Schumann, T.

    1994-01-01

    Solid sampling with laser vaporization has been coupled to an ICP emission spectrometer with an Echelle optical system and a solid-state-detector for the analysis of steel and soil samples. Pulsation of the vaporized material flow was compensated by real-time background correction and internal standardization, resulting in good accuracy and precision. (orig.)

  13. Observations of spectroscopic binaries with a solid-state detector

    International Nuclear Information System (INIS)

    Fekel, F. Jr.; Lacy, C.H.; Tomkin, J.

    1980-01-01

    The recent installation of a solid-state 1024-element silicon photodiode array detector (Reticon) at the coude focus of the 2.7 m McDonald Observatory reflector has greatly extended its limits of observation for binary and multiple systems which have weak and/or broad-lined components. This detector can produce extremely high signal-to-noise ratio observations and has high quantum efficiency over the wavelength region 3000-11000 A. The observational programs of three users of this device are described. (Auth.)

  14. A new NaI(Tl) four-detector layout for field contamination assessment using artificial neural networks and the Monte Carlo method for system calibration

    International Nuclear Information System (INIS)

    Moreira, M.C.F.; Conti, C.C.; Schirru, R.

    2010-01-01

    An NaI(Tl) multidetector layout combined with the use of Monte Carlo (MC) calculations and artificial neural networks(ANN) is proposed to assess the radioactive contamination of urban and semi-urban environment surfaces. A very simple urban environment like a model street composed of a wall on either side and the ground surface was the study case. A layout of four NaI(Tl) detectors was used, and the data corresponding to the response of the detectors were obtained by the Monte Carlo method. Two additional data sets with random values for the contamination and for detectors' response were also produced to test the ANNs. For this work, 18 feedforward topologies with backpropagation learning algorithm ANNs were chosen and trained. The results showed that some trained ANNs were able to accurately predict the contamination on the three urban surfaces when submitted to values within the training range. Other results showed that generalization outside the training range of values could not be achieved. The use of Monte Carlo calculations in combination with ANNs has been proven to be a powerful tool to perform detection calibration for highly complicated detection geometries.

  15. A new NaI(Tl) four-detector layout for field contamination assessment using artificial neural networks and the Monte Carlo method for system calibration

    Energy Technology Data Exchange (ETDEWEB)

    Moreira, M.C.F., E-mail: marcos@ird.gov.b [Universidade Federal do Rio de Janeiro, COPPE, Programa de Engenharia Nuclear, Laboratorio de Monitoracao de Processos (Federal University of Rio de Janeiro, COPPE, Nuclear Engineering Program, Process Monitoring Laboratory), P.O. Box 68509, 21941-972 Rio de Janeiro (Brazil); Instituto de Radioprotecao e Dosimetria, CNEN/IRD (Radiation Protection and Dosimetry Institute, CNEN/IRD), Av. Salvador Allende s/no, P.O. Box 37750, 22780-160 Rio de Janeiro (Brazil); Conti, C.C. [Instituto de Radioprotecao e Dosimetria, CNEN/IRD (Radiation Protection and Dosimetry Institute, CNEN/IRD), Av. Salvador Allende s/no, P.O. Box 37750, 22780-160 Rio de Janeiro (Brazil); Schirru, R. [Universidade Federal do Rio de Janeiro, COPPE, Programa de Engenharia Nuclear, Laboratorio de Monitoracao de Processos (Federal University of Rio de Janeiro, COPPE, Nuclear Engineering Program, Process Monitoring Laboratory), P.O. Box 68509, 21941-972 Rio de Janeiro (Brazil)

    2010-09-21

    An NaI(Tl) multidetector layout combined with the use of Monte Carlo (MC) calculations and artificial neural networks(ANN) is proposed to assess the radioactive contamination of urban and semi-urban environment surfaces. A very simple urban environment like a model street composed of a wall on either side and the ground surface was the study case. A layout of four NaI(Tl) detectors was used, and the data corresponding to the response of the detectors were obtained by the Monte Carlo method. Two additional data sets with random values for the contamination and for detectors' response were also produced to test the ANNs. For this work, 18 feedforward topologies with backpropagation learning algorithm ANNs were chosen and trained. The results showed that some trained ANNs were able to accurately predict the contamination on the three urban surfaces when submitted to values within the training range. Other results showed that generalization outside the training range of values could not be achieved. The use of Monte Carlo calculations in combination with ANNs has been proven to be a powerful tool to perform detection calibration for highly complicated detection geometries.

  16. Direct and indirect signal detection of 122 keV photons with a novel detector combining a pnCCD and a CsI(Tl) scintillator

    Energy Technology Data Exchange (ETDEWEB)

    Schlosser, D.M., E-mail: dieter.schlosser@pnsensor.de [PNSensor GmbH, Sckellstraße 3, 81667 München (Germany); Huth, M.; Hartmann, R. [PNSensor GmbH, Sckellstraße 3, 81667 München (Germany); Abboud, A.; Send, S. [Universität Siegen, Walter-Flex-Straße 3, 57072 Siegen (Germany); Conka-Nurdan, T. [Türkisch-Deutsche Universität, Sakinkaya Cad. 86, Beykoz, 34820 Istanbul (Turkey); Shokr, M.; Pietsch, U. [Universität Siegen, Walter-Flex-Straße 3, 57072 Siegen (Germany); Strüder, L. [PNSensor GmbH, Sckellstraße 3, 81667 München (Germany); Universität Siegen, Walter-Flex-Straße 3, 57072 Siegen (Germany)

    2016-01-01

    By combining a low noise fully depleted pnCCD detector with a CsI(Tl) scintillator, an energy-dispersive area detector can be realized with a high quantum efficiency (QE) in the range from below 1 keV to above 100 keV. In direct detection mode the pnCCD exhibits a relative energy resolution of 1% at 122 keV and spatial resolution of less than 75 µm, the pixel size of the pnCCD. In the indirect detection mode, i.e. conversion of the incoming X-rays in the scintillator, the measured energy resolution was about 9–13% at 122 keV, depending on the depth of interaction in the scintillator, while the position resolution, extracted with the help of simulations, was 30 µm only. We show simulated data for incident photons of 122 keV and compare the various interaction processes and relevant physical parameters to experimental results obtained with a radioactive {sup 57}Co source. - Highlights: • Position and energy resolving pnCCD+CsI(Tl) detector for energies from 1-150 keV • Detection in the pnCCD (122keV): 1% energy and <75µm spatial resolution • Detection in the scintillator (122keV): 9-12% energy and ~30µm spatial resolution.

  17. Ground level cosmic ray pulse height spectrum of a 7. 5 cm diameter spherical NaI(Tl) scintillation detector for energy region below 5 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Nagaoka, Toshi; Saito, Kimiaki; Moriuchi, Shigeru

    1988-09-01

    Ground level cosmic ray pulse height spectrum of a 7.5 cm diameter spherical NaI(Tl) scintillation detector was evaluated through stripping operation based on a pulse height spectrum measured on the sea and high precision response functions of the detector for U-series, Th-series and /sup 40/K. The exposure rate calculated from the determined cosmic ray pulse height spectrum was 0.21 R/h eq., which agreed well with that obtained from another method. The shape of the pulse height spectrum showed similarity to that measured at the altitude of 16,000 ft, especially in the energy region of 0 to 3 MeV. The principle of the adopted method is rather plain, however, the reliability of the spectrum is satisfactory. As the pulse height spectrum is a common information to any analytical method for environmental gamma ray using NaI(Tl) scintillation detector, it is expected to be used for simple and precise separation of cosmic ray component involved in the enviromental pulse height spectrum.

  18. Effect of crystal shape, size and reflector type on operation characteristics of gamma-radiation detectors based on CsI(Tl) and CsI(Na) scintillators

    International Nuclear Information System (INIS)

    Globus, M.E.; Grinyov, B.V.; Ratner, M.A.

    1996-01-01

    Operation characteristics of CsI(Tl) and CsI(Na) scintillation detectors, to a large degree connected with light collection in crystals, are calculated for various shapes, sizes and reflecting surface types. Allowance is made for the true light reflection indicatrix which is characterized by the effective mirror constituent of the reflected light, p. Its value , averaged over incidence angle, is used for the classification of reflecting surfaces. Operation characteristics (in particular, spectrometric ones) are found to be essentially dependent on . Tables of operation characteristics, given below, permit one to make inferential conclusions on an optimal combination of the shape, sizes an the reflecting surface version

  19. Applications of a pnCCD detector coupled to columnar structure CsI(Tl) scintillator system in ultra high energy X-ray Laue diffraction

    Science.gov (United States)

    Shokr, M.; Schlosser, D.; Abboud, A.; Algashi, A.; Tosson, A.; Conka, T.; Hartmann, R.; Klaus, M.; Genzel, C.; Strüder, L.; Pietsch, U.

    2017-12-01

    Most charge coupled devices (CCDs) are made of silicon (Si) with typical active layer thicknesses of several microns. In case of a pnCCD detector the sensitive Si thickness is 450 μm. However, for silicon based detectors the quantum efficiency for hard X-rays drops significantly for photon energies above 10 keV . This drawback can be overcome by combining a pixelated silicon-based detector system with a columnar scintillator. Here we report on the characterization of a low noise, fully depleted 128×128 pixels pnCCD detector with 75×75 μm2 pixel size coupled to a 700 μm thick columnar CsI(Tl) scintillator in the photon range between 1 keV to 130 keV . The excellent performance of the detection system in the hard X-ray range is demonstrated in a Laue type X-ray diffraction experiment performed at EDDI beamline of the BESSY II synchrotron taken at a set of several GaAs single crystals irradiated by white synchrotron radiation. With the columnar structure of the scintillator, the position resolution of the whole system reaches a value of less than one pixel. Using the presented detector system and considering the functional relation between indirect and direct photon events Laue diffraction peaks with X-ray energies up to 120 keV were efficiently detected. As one of possible applications of the combined CsI-pnCCD system we demonstrate that the accuracy of X-ray structure factors extracted from Laue diffraction peaks can be significantly improved in hard X-ray range using the combined CsI(Tl)-pnCCD system compared to a bare pnCCD.

  20. Fast neutron detection using solid state nuclear track detectors

    International Nuclear Information System (INIS)

    Vilela, E.C.

    1990-01-01

    CR-39 and Makrofol-E solid state nuclear track detectors were studied aiming their application to fast neutron detection. Optimum etching conditions of those two kinds of materials were determined the followings - the Makrofol-E detector is electrochemically etched in a PEW solution (15% KOH, 40% ethilic alcohol and 45% water) for 2 h., with an applied electric field strength of 30 kV/cm (r/m/s/) and frequency of 2 kHz, at room temperature; - the CR-39 detector is chemically pre-etched during 1 h in a 20% (w/v) NaOH solution at 70 sup(0)C, followed by 13 h electrochemical etch using the same solution at room temperature and an electric field strength of 30 kV/cm (r.m.s.) and frequency of 2 kHz.(E.G.)

  1. Diallyl phthalate (DAP) solid state nuclear track detector

    CERN Document Server

    Koguchi, Y; Ashida, T; Tsuruta, T

    2003-01-01

    Diallyl phthalate (DAP) solid state nuclear track detector is suitable for detecting heavy ions such as fission fragments, because it is insensitive to right ions such as alpha particles and protons. Detection efficiency of fission tracks is about 100%, which is unaffected under conditions below 240degC lasting for 1h or below 1 MGy of gamma-ray irradiation. Optimum etching condition for the DAP detector for detection of fission fragments is 2-4 h using 30% KOH aqueous solution at 90degC or 8-15 min using PEW-65 solution at 60degC. DAP detector is useful in detecting induced fission tracks for dating of geology or measuring intense heavy ions induced by ultra laser plasma. The fabrication of copolymers of DAP and CR-39 makes it possible to control the discrimination level for detection threshold of heavy ions. (author)

  2. Application of solid state track detector to neutron dosimetry

    International Nuclear Information System (INIS)

    Tsuruta, Takao

    1979-01-01

    Though solid state track detectors (SSTD) are radiation measuring instrument for heavy charged particles by itself, it can be used as radiation measuring instrument for neutrons, if nuclear reactions such as (n, f) or (n, α) reaction are utilized. Since the means was found, which permits to observe the tracks of heavy charged particles in a solid with an optical microscope by chemically etching the tracks to enlarge them to etch pits, various types of detectors have been developed for the purpose of measuring neutron dose. The paper is described on the materials and construction of the SSTDs for neutron dosimetry, and the sensitivity is explained with mathematical equations. The features of neutron dosimetry with SSTDs are as follows: They are compact, and scarcely disturb neutron field, thus delicate dose distribution can be known; integration measurement is possible regardless of dose rate values because of integrating type detectors; it is not influenced by β-ray or γ-ray except the case when there is high energy radiation such as causing photonuclear reactions or high dose such as degrading solids, it has pretty high sensitivity; track fading is negligible during the normal measuring time around room temperature; and the etching images of tracks are relatively clear, and various automatic counting systems can be employed. (Wakatsuki, Y.)

  3. Energy spectrum of charge carriers in TlIn{sub 1–x}Yb{sub x}Te{sub 2} solid solutions

    Energy Technology Data Exchange (ETDEWEB)

    Aliev, F. F., E-mail: farzali@physics.ab.az [Azerbaijan National Academy of Sciences, Institute of Physics (Azerbaijan); Agaeva, U. M.; Zarbaliev, M. M., E-mail: zarbalievmm51@mail.ru [Sumqayit State University (Azerbaijan)

    2016-10-15

    The temperature dependences of the electrical conductivity σ(T), the Hall coefficient R(T), and the thermoelectric coefficient α(T) are investigated in TlIn{sub 1–x}Yb{sub x}Te{sub 2} (0 < x < 0.10) solid solutions at 80–1000K. From the kinetic parameters, the effective masses of electrons and holes are determined. The obtained experimental data on σ(T) and α(T) are interpreted within the context of a model with one and two types of charge carriers. It is established that, since x = 0.05, the TlIn{sub 1–x}Yb{sub x}Te{sub 2} solid solutions belong to the class of narrow-gap semiconductors that have high matrix elements of interaction.

  4. Design and performance of modularized NaI(Tl) detectors with rectangular crystal elements: An array of 49 and the Crystal Box

    International Nuclear Information System (INIS)

    Wilson, S.L.; Hofstadter, R.; Hughes, E.B.; Lin, Y.C.; Parks, R.; Rolfe, J.; Bolton, R.D.; Bowman, J.D.; Cooper, M.D.; Hoffman, C.M.; Hogan, G.E.; Mariam, F.G.; Mischke, R.E.; Nagle, D.E.; Piilonen, L.E.; Sandberg, V.D.; Sanders, G.H.; Werbeck, R.; Williams, R.A.; Frank, J.S.; Hallin, A.L.; Matis, H.S.; Sennhauser, U.; Wright, S.C.

    1988-01-01

    An array of 49 NaI(Tl) modules each 20 inch in depth and 2.5 inch x 2.5 inch in cross section has been constructed and its properties, especially energy resolution, explored for positrons in the range 20 MeV - 18 GeV. A subsequent much larger detector, the Crystal Box, has also been constructed from 396 modules of the same cross section, but mostly 12 inch in depth, and operated as a γ-ray and positron detector in a search for rare muon decays. The calibration procedure used for the Crystal Box and its characteristic resolutions in energy, impact point and time are described. (orig.)

  5. A position sensitive detector using a NaI(Tl)/photomultiplier tube combination for the energy range 200 keV to 10 MeV

    International Nuclear Information System (INIS)

    Court, A.J.; Dean, A.J.; Yearworth, M.; Younis, F.; Chiappetti, L.; Perotti, F.; Villa, G.; Ubertini, P.; La Padula, C.

    1988-01-01

    The performance of the position sensitive detector for the ZEBRA low energy gamma-ray imaging telescope is described. The detector consists of 9 position sensitive NaI(Tl) elements each 5.8x5.0x56.0 cm viewed at either end of the long axis by 2 in. photomultiplier tubes. The total active area is 2470 cm 2 with an average positional resolution of 2.1 cm and energy resolution of 15% FWHM at 661.6 keV. The method of flight calibration is described together with the provision within the on-board electronics to correct for sources of error in the calculation of event energy loss and position. The results presented are obtained from the calibration phase of the ZEBRA telescope project. (orig.)

  6. Evaluation of the relative thermoluminescence efficiency of LiF:Mg,Ti and LiF:Mg,Cu,P TL detectors to low-energy heavy ions

    DEFF Research Database (Denmark)

    Gieszczyk, W.; Bilski, P.; Olko, P.

    2013-01-01

    and xenon ion beams, at energies ranging from 5.0 to 9.3 MeV/n. Supra- and sublinear response was found, for the MTS-N and MCP-N, respectively, similarly as observed for γ-rays. However, the level of nonlinearity of response of studied detectors is strongly reduced by increasing values of the ion ionization...... density (no supralinearity for Xe ions, for MTS-N, within calculated uncertainties). The growth of high-temperature TL peaks, with increasing ionization density, was observed for MCP-N, what was not previously reported. At the whole range of applied energies higher efficiencies were noted for MTS......-N, for all ion species. A decrease of the efficiency with decrease of the ion energy was confirmed, for both types of studied detectors. At a given energy, higher efficiency was observed for lighter ions, because of the lower ionization density. Significantly higher decrease of the efficiency was measured...

  7. The NSLS 100 element solid state array detector

    International Nuclear Information System (INIS)

    Furenlid, L.R.; Beren, J.; Kraner, H.W.; Rogers, L.C.; Stephani, D.; Beuttenmuller, R.H.; Cramer, S.P.

    1992-01-01

    X-ray absorption studies of dilute samples require fluorescence detection techniques. Since signal-to-noise ratios are governed by the ratio of fluorescent to scattered photons counted by a detector, solid state detectors which can discriminate between fluorescence and scattered photons have become the instruments of choice for trace element measurements. Commercially available 13 element Ge array detectors permitting total count rates < 500 000 counts per second are now in routine use. Since X-ray absorption beamlines at high brightness synchrotron sources can already illuminate most dilute samples with enough flux to saturate the current generation of solid state detectors, the development of next-generation instruments with significantly higher total count rates is essential. We present the design and current status of the 100 elements Si array detector being developed in a collaboration between the NSLS and the Instrumentation Division at Brookhaven National Laboratory. The detecting array consists of a 10 x 10 matrix of 4 mm x 4 mm elements laid out on a single piece of ultrahigh purity silicon mounted at the front end of a liquid nitrogen dewar assembly. A matrix of charge sensitive integrating preamplifiers feed signals to an array of shaping amplifiers, single channel analyzers, and scalers. An electronic switch, delay amplifier, linear gate, digital scope, peak sensing A/D converter, and histogramming memory module provide for complete diagnostics and channel calibration. The entrie instrument is controlled by a LabView 2 application on a MacII ci; the software also provides full control over beamline hardware and performs the data collection. (orig.)

  8. Phototransfered thermoluminescence for dose reassessment in LiF:mg,ti , LiF: mg,Cu,p TL detectors

    International Nuclear Information System (INIS)

    Rodriguez Otazo, M.; Baly, L.

    2001-01-01

    Phototransfered Thermoluminescence (PTTL) from LiF:Mg,Ti (TLD-100) and LiF: Mg,Cu,P (GR-200) was studied at different conditions using different sources of UV light for dose reassessment purposes. The TL dosimeters were irradiated with 137Cs in the range 2 mGy to 100 mGy. The convenience of using PTTL for dose reassessment was analyzed

  9. Application of the dose rate spectroscopy to the dose-to-curie conversion method using a NaI(Tl) detector

    International Nuclear Information System (INIS)

    JI, Young-Yong; Chung, Kun Ho; Kim, Chang-Jong; Kang, Mun Ja; Park, Sang Tae

    2015-01-01

    Dose rate spectroscopy is a very useful method to directly calculate the individual dose rate from the converted energy spectrum for the dose rate using the G-factor which is related to the used detector response function. A DTC conversion method for the estimation of the radioactivity based on the measured dose rate from the radioactive materials can then be modified into a simple equation using the dose rate spectroscopy. In order to make the method validation of the modified DTC conversion method, experimental verifications using a 3″φx3″ NaI(Tl) detector were conducted at the simple geometry of the point source located onto a detector and more complex geometries which mean the assay of the simulated radioactive material. In addition, the linearity about the results from the modified DTC conversion method was also estimated by increasing the distance between source positions and a detector to confirm the method validation in the energy, dose rate, and distance range of the gamma nuclides. - Highlights: • A modified DTC conversion method using the dose rate spectroscopy was established. • In-situ calibration factors were calculated from the MCNP simulation. • Radioactivities of the disk sources were accurately calculated using a modified DTC conversion method. • A modified DTC conversion method was applied to the assay of the radioactive material

  10. Background problem for a large solid angle, high sensitivity detector

    International Nuclear Information System (INIS)

    Chen, M.

    1977-01-01

    With extremely good vacuum (10 -11 to 10 -13 torr) and well controlled beams, the ISR has a good reputation for clean beam conditions and low background for most types of experiments. However, for a detector covering a large solid angle, measuring processes with small cross sections (approximately 10 -38 cm 2 ) there are serious background problems which took almost a year to solve. Since ISABELLE may have similar problems, a summary is given of experience at the ISR with the hope that some of the solutions can be installed in ISABELLE at an early stage

  11. Radon detection in soils by solid state nuclear track detectors

    International Nuclear Information System (INIS)

    Moraes, M.A.P.V. de; Khouri, M.T.F.C.

    1986-01-01

    The solid state nuclear track detectors technique was developed to be used in radon detection, by alpha particles tracks, and its application in uranium prospecting on the ground. The sensitive films to alpha particles used are the cellulose nitrate films LR 115 and CA 8015. Several simulations experiments and field measurements were carried out to verify the method possibilities. Maps of some anomalies in Caetite City (Bahia, Brazil) were made with the densities of tracks obtained. The results were compared with scintillation counter measurements. (Author) [pt

  12. Limits on Interactions between Weakly Interacting Massive Particles and Nucleons Obtained with CsI(Tl) Crystal Detectors

    International Nuclear Information System (INIS)

    Lee, H. S.; Bhang, H. C.; Choi, J. H.; Kim, D. W.; Kim, S. C.; Kim, S. K.; Kwak, J. W.; Lee, J.; Lee, J. H.; Lee, M. J.; Lee, S. J.; Myung, S. S.; Ryu, S.; Dao, H.; Li, J.; Li, X.; Li, Y. J.; Yue, Q.; Zhu, J. J.; Hahn, I. S.

    2007-01-01

    The Korea Invisible Mass Search (KIMS) experiment presents new limits on the weakly interacting massive particle (WIMP)-nucleon cross section using data from an exposure of 3409 kg·d taken with low-background CsI(Tl) crystals at the Yangyang Underground Laboratory. The most stringent limit on the spin-dependent interaction for a pure proton case is obtained. The DAMA signal region for both spin-independent and spin-dependent interactions for the WIMP masses greater than 20 GeV/c 2 is excluded by the single experiment with crystal scintillators

  13. Detection alpha particles and Cf-252 fission fragments with track solid detectors and with surface barrier detectors: efficiency determination

    International Nuclear Information System (INIS)

    Khouri, M.T.F.C.; Koskinas, M.F.; Andrade, C. de; Vilela, E.C.; Hinostroza, H.; Kaschiny, J.R.A.; Costa, M.S. da; Rizzo, P.; Santos, W.M.S.

    1990-01-01

    The technique of particle detection by solid track detectors, types of developing and analysis of results are presented. Efficiency measurements of alpha particle detection with Makrofol e and surface barrier detector are made. Detection of Cf-252 fission fragments is shown. (L.C.)

  14. Detection of alpha particles and Cf-252 fission fragments with solid track detectors and surface barrier detector. Efficiency calculation

    International Nuclear Information System (INIS)

    Khouri, M.T.F.C.; Koskinas, M.F.; Andrade, C. de; Vilela, E.C.; Hinostroza, H.; Kaschiny, J.E.A.; Costa, M.S. da; Rizzo, P.; Santos, W.M.S.

    1990-01-01

    A technique for particle detection by using track solid detector and also types of revealing and result analysis are presented concerned to Cf-252 fission fragments detection. Measurements of alpha particles detection efficiency using Makrofol E and surface barrier detector are performed. (L.C.J.A.)

  15. The response of different types of TL lithium fluoride detectors to high-energy mixed radiation fields

    Energy Technology Data Exchange (ETDEWEB)

    Obryk, B. [Institute of Nuclear Physics PAN (IFJ), ul. Radzikowskiego 152, 31-342 Krakow (Poland)], E-mail: barbara.obryk@ifj.edu.pl; Bilski, P.; Budzanowski, M. [Institute of Nuclear Physics PAN (IFJ), ul. Radzikowskiego 152, 31-342 Krakow (Poland); Fuerstner, M. [CERN - European Organization for Nuclear Research, 1211 Geneva 23 (Switzerland); Ilgner, C. [CERN - European Organization for Nuclear Research, 1211 Geneva 23 (Switzerland) and University of Dortmund, Dortmund (Germany); Jaquenod, F. [Ecole d' Ingenieurs de Geneve, Geneva (Switzerland); Olko, P.; Puchalska, M. [Institute of Nuclear Physics PAN (IFJ), ul. Radzikowskiego 152, 31-342 Krakow (Poland); Vincke, H. [CERN - European Organization for Nuclear Research, 1211 Geneva 23 (Switzerland)

    2008-02-15

    Thermoluminescent (TL) dosimeters are routinely used to monitor absorbed doses in many kinds of radiation fields which contain photons, electrons and neutrons. However, TLDs are mainly calibrated to photon sources. We studied the response of TLDs to complex secondary fields arising during the operation of high-energy accelerators (e.g. the Large Hadron Collider (LHC) at CERN). The experiments were conducted at the CERN-EU high-energy reference field facility (CERF). Six different LiF-based TLDs (MTS-N, MTS-7, MTS-6, MCP-N, MCP-7, MCP-6) were exposed to various secondary CERF's fields (both for high and low doses), by placing them at various positions: at the target and concrete top and side positions. For the experiment at the target the corresponding Monte Carlo calculations were also carried out using the FLUKA transport code and compared with experimental results. In addition, alanine dosimeters were used as an independent reference. The results show that TLDs are well suited for monitoring radiation fields around the LHC. Nevertheless, further investigations are required, some of which are in progress.

  16. MCNP-X Monte Carlo Code Application for Mass Attenuation Coefficients of Concrete at Different Energies by Modeling 3 × 3 Inch NaI(Tl Detector and Comparison with XCOM and Monte Carlo Data

    Directory of Open Access Journals (Sweden)

    Huseyin Ozan Tekin

    2016-01-01

    Full Text Available Gamma-ray measurements in various research fields require efficient detectors. One of these research fields is mass attenuation coefficients of different materials. Apart from experimental studies, the Monte Carlo (MC method has become one of the most popular tools in detector studies. An NaI(Tl detector has been modeled, and, for a validation study of the modeled NaI(Tl detector, the absolute efficiency of 3 × 3 inch cylindrical NaI(Tl detector has been calculated by using the general purpose Monte Carlo code MCNP-X (version 2.4.0 and compared with previous studies in literature in the range of 661–2620 keV. In the present work, the applicability of MCNP-X Monte Carlo code for mass attenuation of concrete sample material as building material at photon energies 59.5 keV, 80 keV, 356 keV, 661.6 keV, 1173.2 keV, and 1332.5 keV has been tested by using validated NaI(Tl detector. The mass attenuation coefficients of concrete sample have been calculated. The calculated results agreed well with experimental and some other theoretical results. The results specify that this process can be followed to determine the data on the attenuation of gamma-rays with other required energies in other materials or in new complex materials. It can be concluded that data from Monte Carlo is a strong tool not only for efficiency studies but also for mass attenuation coefficients calculations.

  17. NaI(Tl) response functions

    International Nuclear Information System (INIS)

    Vega C, H. R.; Ortiz R, J. M.; Benites R, J. L.; De Leon M, H. A.

    2015-09-01

    The response functions of a NaI(Tl) detector have been estimated using Monte Carlo methods. Response functions were calculated for monoenergetic photon sources (0.05 to 3 MeV). Responses were calculated for point-like sources and for sources distributed in Portland cement cylinders. The responses were used to calculate the efficiency functions in term of photon energy. Commonly, sources used for calibration are point-like, and eventually sources to be measured have different features. In order to use the calibrated sources corrections due to solid angle, self-absorption and scattering, must be carried out. However, some of these corrections are not easy to perform. In this work, the calculated responses were used to estimate the detector efficiency of point-like sources, and sources distributed in Portland type cement. Samples of Portland paste were prepared and were exposed to photoneutrons produced by a 15 MV linac. Some of the elements in the cement were activated producing γ-emitting radionuclides that were measured with a NaI(Tl) gamma-ray spectrometer, that was calibrated with point-like sources. In order to determine the specific activity in the induced radioisotopes calculated efficiencies were used to make corrections due to the differences between the solid angle, photon absorption and photon scattering in the point-like calibration sources and the sources distributed in cement. During the interaction between photoneutrons and the cement samples three radioisotopes were induced: 56 Mn, 24 Na, and 28 Al. (Author)

  18. Solid state nuclear track detectors and their application in industrial health, radiological and environmental protection

    International Nuclear Information System (INIS)

    Urban, M.

    1993-09-01

    Passive Solid State Nuclear Track Detectors are electrically non conductive solids, mainly used for the registration of α-particles and neutron induced recoils. The stability of the particle tracks in the solid allow longer integration periods, what is essential for the measurement of small, time variant radiation exposures. This report gives an overview on non-photographic track detectors, their processing, dosimetric properties and examples for their application in industrial health, radiological and environmental protection. (orig.) [de

  19. Theoretical calibration of a NaI(Tl) detector for the measurement of {sup 131}I in a thyroid phantom; Calibracao teorica de um detetor NaI(Tl) para a determinacao de {sup 131}I em um simulador de tireoide

    Energy Technology Data Exchange (ETDEWEB)

    Venturini, Luzia [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil). Dept. de Metrologia das Radiacoes]. E-mail: lventur@net.ipen.br

    2002-07-01

    This paper describes the theoretical calibration of a NaI(Tl) detector using Monte Carlo Method, for the measurement of {sup 131} I in a thyroid phantom. The thyroid is represented by the region between two concentric cylinders, where the inner one represents the trachea and the outer one represents the neck. {sup 133} Ba was used for experimental calibration. The results shows that the calibration procedure is suitable for {sup 131} I measurements. (author)

  20. Influence of tracks densities in solid state nuclear track detectors

    International Nuclear Information System (INIS)

    Guedes O, S.; Hadler N.; Lunes, P.; Saenz T, C.

    1996-01-01

    When Solid State Nuclear Track Detectors (SSNTD) is employed to measure nuclear tracks produced mainly by fission fragments and alpha particles, it is considered that the tracks observation work is performed under an efficiency, ε 0 , which is independent of the track density (number of tracks/area unit). There are not published results or experimental data supporting such an assumption. In this work the dependence of ε 0 with track density is studied basing on experimental data. To perform this, pieces of CR-39 cut from a sole 'mother sheet' were coupled to thin uranium films for different exposition times and the resulting ratios between track density and exposition time were compared. Our results indicate that ε 0 is constant for track densities between 10 3 and 10 5 cm -2 . At our etching conditions track overlapping makes impossible the counting for densities around 1.7 x 10 5 cm -2 . For track densities less than 10 3 cm -2 , ε 0 , was not observed to be constant. (authors). 4 refs., 2 figs

  1. Study by Monte Carlo methods of an explosives detection system made up with a D-D neutron generator and NaI(Tl) gamma detectors.

    Science.gov (United States)

    Cevallos Robalino, Lenin E; García Fernández, Gonzalo Felipe; Gallego, Eduardo; Guzmán-García, Karen A; Vega-Carrillo, Hector Rene

    2018-02-17

    Detection of hidden explosives is of utmost importance for homeland security. Several configurations of an Explosives Detection System (EDS) to intercept hidden threats, made up with a Deuterium-Deuterium (D-D) compact neutron generator and NaI (Tl) scintillation detectors, have been evaluated using MCNP6 code. The system's response to various samples of explosives, such as RDX and Ammonium Nitrate, is analysed. The D-D generator is able to produce fast neutrons with 2.5 MeV energy in a maximum yield of 10 10 n/s. It is surrounded by high-density polyethylene to thermalize the fast neutrons and to optimize interactions with the sample inspected, whose emission of gamma rays gives a characteristic spectrum of the elements that constitute it. This procedure allows to determine its chemical composition and to identify the type of substance. The necessary shielding is evaluated to estimate its thicknesses depending on the admissible dose of operation, using lead and polyethylene. The results show that its functionality is promising in the field of national security for explosives inspection. Copyright © 2018 Elsevier Ltd. All rights reserved.

  2. 205Tl experiment

    International Nuclear Information System (INIS)

    Henning, W.; Kutschera, W.; Ernst, H.

    1984-01-01

    205 Tl has been previously proposed as a geological detector for solar neutrinos, making use of the reaction 205 Tl(nu, e - ) 205 Pb with a neutrino threshold of only approx. = 43 keV. We report on an experiment performed to study the feasibility of detecting radioactive 205 Pb nuclei (T/sub 1/2/ = 15 million years) at very low concentrations using the recently developed technique of accelerator mass spectrometry. Employing the high-energy ion beams of good quality from the UNILAC heavy-ion accelerator at the GSI Darmstadt, we are able to demonstrate a suppression of neighbouring isotopes to better than 1 in 10 16 and of neighbouring elements to about 1 in 10 3 . While these results are very encouraging, the minimum number of atoms detectable is still severely limited by the efficiency of producing multiply-charged ions from present ion sources. Future improvements in ion-source performance are briefly discussed

  3. The solid state track detectors for α-particles angular distribution measurements

    International Nuclear Information System (INIS)

    Bakr, M.H.S.

    1978-01-01

    The solid state track detectors technique is described in details from the point of view of applying them in nuclear reactions research. Using an optimum developing solution, the etching rate of polycarbonate detector was found to be 10.5 μ/hour. The energy resolution of this detector was estimated using 241 Am α-source at α-energies between 1 and 3 Mev. The scattering chamber designed for angular distribution measurements using solid state track detectors is described. A special schematic normograph for range-energy-degrading foils relation is given

  4. 2. International workshop Solid state nuclear track detectors and their applications

    International Nuclear Information System (INIS)

    Perelygin, V.P.

    1992-01-01

    The 2. Workshop on Solid state nuclear track detectors (SSNTD) held in Dubna, 24-26 Mar 1992. Possibilities of SSNTD applications in the fields of high and low energy physics, dosimetry and radioecology were discussed

  5. Critical angles for fission fragment registrations in some solid state track detectors

    Energy Technology Data Exchange (ETDEWEB)

    Belyaev, A D; Bahromi, I I; Beresina, N V [AN Uzbekskoj SSR, Tashkent. Inst. Yadernoj Fiziki; and others

    1980-03-01

    In studies of the registration efficiency of various solid state track detectors (polycarbonate, polyethyleneterephthalate, cellulose nitrate and muscovite) the detectors were irradiated with spontaneous fission fragments from /sup 252/Cf and with fission fragments from /sup 235/U separated according to mass and energy. Experimental details are given. Critical angles for the registration of fission fragments in the various detectors are given for specified energies and masses.

  6. Solid-state, flat-panel, digital radiography detectors and their physical imaging characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Cowen, A.R. [LXi Research, Academic Unit of Medical Physics, University of Leeds, West Yorkshire (United Kingdom)], E-mail: a.r.cowen@leeds.ac.uk; Kengyelics, S.M.; Davies, A.G. [LXi Research, Academic Unit of Medical Physics, University of Leeds, West Yorkshire (United Kingdom)

    2008-05-15

    Solid-state, digital radiography (DR) detectors, designed specifically for standard projection radiography, emerged just before the turn of the millennium. This new generation of digital image detector comprises a thin layer of x-ray absorptive material combined with an electronic active matrix array fabricated in a thin film of hydrogenated amorphous silicon (a-Si:H). DR detectors can offer both efficient (low-dose) x-ray image acquisition plus on-line readout of the latent image as electronic data. To date, solid-state, flat-panel, DR detectors have come in two principal designs, the indirect-conversion (x-ray scintillator-based) and the direct-conversion (x-ray photoconductor-based) types. This review describes the underlying principles and enabling technologies exploited by these designs of detector, and evaluates their physical imaging characteristics, comparing performance both against each other and computed radiography (CR). In standard projection radiography indirect conversion DR detectors currently offer superior physical image quality and dose efficiency compared with direct conversion DR and modern point-scan CR. These conclusions have been confirmed in the findings of clinical evaluations of DR detectors. Future trends in solid-state DR detector technologies are also briefly considered. Salient innovations include WiFi-enabled, portable DR detectors, improvements in x-ray absorber layers and developments in alternative electronic media to a-Si:H.

  7. Status and trends of solid state track detector use in radiation protection monitoring

    International Nuclear Information System (INIS)

    Doerschel, B.

    1980-01-01

    The characteristic properties of solid state track detectors allow them to be used for determining the radiation fields of charged and uncharged particles and, consequently, for solving some problems involved in radiation protection monitoring. Aptitude of various detector materials is investigated on the basis of the track formation mechanism taking into account the properties of the particles to be detected. Use of these detectors in radiation protection monitoring presumes appropriate methods of intensifying the latent tracks, which are discussed as a function of various physical parameters. Readout methods of solid state track detectors are based on variations in detector properties determined by number and size of particle tracks in the detector. The choice of a special readout method, among other things, depends on the purpose, detector material, and pretreatment of the detectors. The most prospective methods are described and investigated with respect to their possible use in various fields of radiation protection monitoring. The trends of development of the application of solid state track detectors in radiation protection monitoring are discussed, using some typical applications as examples. (author)

  8. Analysis of dosimetric peaks of MgB4O7:Dy (40% Teflon versus LiF:Mg,Ti TL detectors

    Directory of Open Access Journals (Sweden)

    Paluch-Ferszt Monika

    2016-03-01

    Full Text Available Magnesium tetraborate doped with dysprosium (MgB4O7:Dy is known as a good thermoluminophor for personal dosimetry of gamma ray and X-ray radiation because of its high sensitivity and close tissue equivalence. This material can be produced by different routes. The sintered pastilles of magnesium tetraborate mixed with Teflon (40% used in this work were manufactured at the Federal University of Sergipe, Department of Physics by the solid-state synthesis. Magnesium tetraborate was already used for high-dose dosimetry, exhibiting linearity for a wide range of doses. In this work, the authors examined its main characteristics prior to potential use of detectors in everyday dosimetry, comparing this material to a widely used LiF:Mg,Ti phosphor. The following tests influencing dosimetric peaks of MgB4O7:Dy were presented: (1 the shape of the glow curves, (2 annealing conditions and post-irradiation annealing and its influence for background of the detectors, (3 the choice of the heating rates at the read-out and (4 the threshold dose, that is, the lowest possible dose to be measured. Similar tests were performed with LiF:Mg,Ti detectors, produced and widely used in Poland. The results were compared and discussed.

  9. Study of the reaction {sup 22}O(p,p') with MUST detector. Development of the Cs(Tl) part of MUST-2 detector; Etude de la reaction {sup 22}O(p,p') avec le detecteur MUST. Developpement de l'etage CsI(Tl) de l'ensemble MUST 2

    Energy Technology Data Exchange (ETDEWEB)

    Becheva, E

    2004-11-01

    Elastic and inelastic proton scattering on the unstable nuclei {sup 22}O was measured in inverse kinematics at the GANIL facility. A secondary beam of {sup 22}O at 46.6 MeV/A with intensity of {approx} 1000 pps, impinged on a (CH{sub 2}){sub n} target. Recoiling protons were detected in the silicon strip array MUST. We measured the angular distributions of the ground and 2{sub 1}{sup +} states of {sup 22}O. Phenomenological and microscopic analysis of the data were performed. The phenomenological analysis using a global potential parameterization of Becchetti and Greenlees and CH89 yields a value of the deformation parameter {beta}{sub p,p}, = 0.23{+-}0.04 for {sup 22}O, much lower than that of {sup 20}O. The ratio of neutron and proton matrix element M{sub n}/M{sub p} is found equal to 1.46{+-}0.50. The microscopic analysis used of densities and transition densities calculated within HFB and QRPA models respectively. Optical potential were obtained through both folding and JLM procedures. A ratio M{sub n}/M{sub p}=2.5{+-}1.0 is deduced. Contrary of {sup 20}O, {sup 22}O behaviours like a doubly magic nucleus, suggesting a pronounced sub-shell closure at N=14. To develop the study of direct reactions induced by radioactive beams, we have developed and built, a new multi-detector MUST II devoted to light charged particle detection. In this work we established the requirements for the CsI(Tl) detector stage, and test four CsI detector prototypes, constructed by the SCIONIX company. (author)

  10. Studies on neutron detection with solid state nuclear track detectors

    International Nuclear Information System (INIS)

    Khouri, M.C.; Vilela, E.C.; Andrade, C. de.

    1993-03-01

    The detection of thermal and fast neutrons was studied. For thermal neutrons, alpha sensitive plastic was used in order to register the products of nuclear reactions taking place in boron and /or lithium converters. Fast neutrons produce recoil tracks within the detector. In the present case, CR-39 and Makrofol E were used. Chemical and electrochemical etching processes were used for thermal and fast neutron detectors, respectively. (F.E.). 6 refs, 4 figs, 6 tabs

  11. Application of solid state nuclear track detectors in radiation protection

    International Nuclear Information System (INIS)

    Ramachandran, T.V.; Subba Ramu, M.C.; Mishra, U.C.

    1989-01-01

    This article reviews the current status of the application of nuclear track detectors with emphasis on recent developments in the field of radiation protection. Track etch detectors have been used for the measurements of low level radiation in the environment, fast neutron and radon daughter inhalation dose. Recent developments in the field of dosimetry seem to be promising. In fast neutron dosimetry, track etch detectors can be used without inclusion of fissile materials by using the electrochemical etching technique. These detectors can provide important information in the energy range upto 250 keV. Survey of this range of energy with TLD is difficult because they are extremely energy dependent and over-respond to low energy neutrons. Measurement of radon using track detectors can help to lower the cost of the radon dosimeters. Certain detectors are sensitive to alpha particles from radon and their progeny. Higher sensitivity permits their use in a passive type of personnel dosimeter, which does not require the troublesome aspects of air sampling for the collection of radon daughter samples. (author), 38 refs., 8 tabs., 12 figs

  12. Dependence on incident angle of solid state detector response to gamma-rays

    International Nuclear Information System (INIS)

    Yamanishi, Hirokuni; Yamaguchi, Satarou; Yamaguchi, Takayuki; Ueki, Kohtaro

    2002-01-01

    The shape and size of a NaI(Tl) scintillator that should maximize response variation with γ-ray incident angle was estimated by analytical model calculation. It proved that, even for gamma rays of energy exceeding 1 MeV, a slab detector measuring 50 cm x 50 cm x 5 cm thick should present a ratio of at least 4 between maximum and minimum responses against incidence at different angles. For a sample case of 60 keV gamma rays, estimation of the incident angle dependence by means of Monte Carlo simulation agreed well with experiment using a CZT detector. The counts from photo-electric peak varied with incident angle roughly along a sine curve. The foregoing finding served as basis for proposing a practical direction finder for γ-ray source operating on the principle of determining the source direction from variations in count with incident angle. (author)

  13. The development of gaseous detectors with solid photocathodes for low temperature applications

    CERN Document Server

    Periale, L.; Iacobaeus, C.; Francke, T.; Lund-Jensen, B.; Pavlopoulos, N.; Picchi, P.; Pietropaolo, F.

    2004-01-01

    There are several applications and fundamental research areas which require the detection of VUV light at cryogenic temperatures. For these applications we have developed and successfully tested special designs of gaseous detectors with solid photocathodes able to operate at low temperatures: sealed gaseous detectors with MgF2 windows and windowless detectors. We have experimentally demonstrated, that both primary and secondary (due to the avalanche multiplication inside liquids) scintillation lights could be recorded by photosensitive gaseous detectors. The results of this work may allow one to significantly improve the operation of some noble liquid gas TPCs.

  14. Fast neutron dosimetry by means of different solid state nuclear track detectors

    International Nuclear Information System (INIS)

    Spurny, F.; Turek, K.

    1977-01-01

    The comparative study of three different types of fast neutron dosimeters based on solid state nuclear track detectors is presented; the dosimeters studied were: - microscopic soda glass in contact with 232 Th; - polycarbonate Makrofol E; and - cellulose nitrate Kodak LR 115. All detectors were evaluated by visual counting in a microscope. The authors have studied such properties as the background, angular as well as energetical dependences of detectors. The results obtained show that all studied detectors are suitable for fast neutron dosimetry; their application depends however on the concrete experimental conditions (neutron spectrum, fluence etc.). Both advantages and disadvantages of each of them are presented. (Auth.)

  15. Study of LiF:Mg,Ti and CaSO4:Dy dosimeters TL response to electron beams of 6 MeV applied to radiotherapy using PMMA and solid water phantoms

    International Nuclear Information System (INIS)

    Bravim, A.; Sakuraba, R.K.; Cruz, J.C.; Campos, L.L.

    2011-01-01

    The performance of CaSO 4 :Dy and LiF:Mg,Ti dosimeters to electron beams applied to radiotherapy was investigated. The TL response of these dosimeters was studied for 6 MeV electron beams using PMMA and Solid Water (SW) phantoms. The dosimeters were previously separated in groups according to their TL individual sensitivities to 60 Co gamma-radiation in air under electronic equilibrium conditions. After that, they were irradiated with 6 MeV electron doses of 0.1, 0.5, 1, 5 and 10 Gy using a linear accelerator Clinac 2100C Varian of Hospital Israelita Albert Einstein – HIAE. The electron beam irradiations were performed using a 10 × 10 cm 2 field size, 100 cm source-phantom surface distance and the dosimeters were positioned at the depth of maximum dose (1.2 cm). The TL readings were carried out between 24 and 32 h after irradiation using a Harshaw 3500 TL reader. The TL dose–response of both type of dosimeters and phantoms presented linear behavior on the electron dose range from 0.1 to 5 Gy CaSO 4 :Dy dosimeter is 21 times more sensitive than LiF:Mg,Ti, dosimeter commonly used in clinical dosimetry. The obtained results indicate that the performance of CaSO 4 :Dy dosimeters is similar to LiF:Mg,Ti dosimeters and this material can be an alternative dosimetric material to be used to clinical electron beams dosimetry.

  16. Standardisation of {sup 18}F by a coincidence method using full solid angle detectors

    Energy Technology Data Exchange (ETDEWEB)

    Nedjadi, Youcef, E-mail: youcef.nedjadi@chuv.c [Institut de Radiophysique Appliquee, Grand Pre 1, 1007 Lausanne (Switzerland); Bailat, Claude; Caffari, Yvan; Bochud, Francois [Institut de Radiophysique Appliquee, Grand Pre 1, 1007 Lausanne (Switzerland)

    2010-07-15

    A solution of {sup 18}F was standardised with a 4{pi}{beta}-4{pi}{gamma} coincidence counting system in which the beta detector is a one-inch diameter cylindrical UPS89 plastic scintillator, positioned at the bottom of a well-type 5''x5'' NaI(Tl) gamma-ray detector. Almost full detection efficiency-which was varied downwards electronically-was achieved in the beta-channel. Aliquots of this {sup 18}F solution were also measured using 4{pi}{gamma} NaI(Tl) integral counting and Monte Carlo calculated efficiencies as well as the CIEMAT-NIST method. Secondary measurements of the same solution were also performed with an IG11 ionisation chamber whose equivalent activity is traceable to the Systeme International de Reference through the contribution IRA-METAS made to it in 2001; IRA's degree of equivalence was found to be close to the key comparison reference value (KCRV). The {sup 18}F activity predicted by this coincidence system agrees closely with the ionisation chamber measurement and is compatible within one standard deviation of the other primary measurements. This work demonstrates that our new coincidence system can standardise short-lived radionuclides used in nuclear medicine.

  17. Measurement of the transport properties of (Sb2Te3)sub(0.75)(Bi2Te3)sub(0.25) solid solution with addition of Tl2Te3

    International Nuclear Information System (INIS)

    Sher, A.

    1983-03-01

    The thermoelectric parameters of the solid solution (Sb 3 Te 3 )sub(0.75)(Bi 2 Te 3 )sub(0.25) in the presence of a low concentration of Tl 3 Te 3 were examined. The electrical conductivity, thermal conductivity, Seebeck coefficient and Hall constant were measured on samples which represent the upper parts of the ingots, in the temperature range 10K-300K. The lattice thermal conductivity, carrier, mobility, effective mass and carrier concentration were calculated from the measured parameters. The variation of the carrier mobility with temperature was similar in all the measured samples. At temperatures higher than 80K the mobility was proportional to Tsup(-33/2). At lower temperatures the mobility approached a saturation value which decreased with increasing Tl 2 Te 3 concentration. At about room temperature, the mobility was already not proportional to Tsup(x). Increasing the Tl 2 Te 3 or Sb 2 Se 3 concentration resulted in a lower deviation from the Tsup(x) dependence and a slower increase in the lattice thermal conductivity with decreasing temperature. Addition of Tl 2 Te 3 to the solid solution resulted in minor improvement in the thermoelectric quality which depends on the mobility, effective mass and lattice thermal conductivity. The thermoelectric properties were nearly the same as those obtained by addition of Sb 2 Se 3 to the solid solution. The addition of Tl 2 Te 3 annuled an effect of increasing carrier concentration with decreasing temperature. It resulted in a slower decrease in the Seebeck coefficient. (H.K.)

  18. Ground level cosmic ray pulse height spectrum of a 7.5 cm diameter spherical NaI(Tl) scintillation detector for energy region below 5 MeV

    International Nuclear Information System (INIS)

    Nagaoka, Toshi; Saito, Kimiaki; Moriuchi, Shigeru

    1988-01-01

    Ground level cosmic ray pulse height spectrum of a 7.5 cm diameter spherical NaI(Tl) scintillation detector was evaluated through stripping operation based on a pulse height spectrum measured on the sea and high precision response functions of the detector for U-series, Th-series and 40 K. The exposure rate calculated from the determined cosmic ray pulse height spectrum was 0.21 μR/h eq., which agreed well with that obtained from another method. The shape of the pulse height spectrum showed similarity to that measured at the altitude of 16,000 ft, especially in the energy region of 0 to 3 MeV. The principle of the adopted method is rather plain, however, the reliability of the spectrum is satisfactory. As the pulse height spectrum is a common information to any analytical method for environmental gamma ray using NaI(Tl) scintillation detector, it is expected to be used for simple and precise separation of cosmic ray component involved in the enviromental pulse height spectrum. (author)

  19. Solid State Neutron Detector - A Review of Status

    International Nuclear Information System (INIS)

    Mukhopadhyay, Sanjoy

    2010-01-01

    The PowerPoint presentation was organized into the following areas: Driving forces behind research in semiconductor neutron devices; The (sup 3)He shortage crisis; Alternative detectors for neutron; Semiconductor diodes coated with boron; Perforated semiconductors for neutron detection; and, Three dimensional pillar and trench structured semiconductors.

  20. NaI(Tl) response functions

    Energy Technology Data Exchange (ETDEWEB)

    Vega C, H. R.; Ortiz R, J. M. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas, Zac. (Mexico); Benites R, J. L. [Centro Estatal de Cancerologia de Nayarit, Calz. de la Cruz 118 Sur, Tepic, Nayarit (Mexico); De Leon M, H. A., E-mail: fermineutron@yahoo.com.mx [Instituto Tecnologico de Aguascalientes, Av. Adolfo Lopez Mateos 1801 Ote., 20155 Aguascalientes, Ags. (Mexico)

    2015-09-15

    The response functions of a NaI(Tl) detector have been estimated using Monte Carlo methods. Response functions were calculated for monoenergetic photon sources (0.05 to 3 MeV). Responses were calculated for point-like sources and for sources distributed in Portland cement cylinders. The responses were used to calculate the efficiency functions in term of photon energy. Commonly, sources used for calibration are point-like, and eventually sources to be measured have different features. In order to use the calibrated sources corrections due to solid angle, self-absorption and scattering, must be carried out. However, some of these corrections are not easy to perform. In this work, the calculated responses were used to estimate the detector efficiency of point-like sources, and sources distributed in Portland type cement. Samples of Portland paste were prepared and were exposed to photoneutrons produced by a 15 MV linac. Some of the elements in the cement were activated producing γ-emitting radionuclides that were measured with a NaI(Tl) gamma-ray spectrometer, that was calibrated with point-like sources. In order to determine the specific activity in the induced radioisotopes calculated efficiencies were used to make corrections due to the differences between the solid angle, photon absorption and photon scattering in the point-like calibration sources and the sources distributed in cement. During the interaction between photoneutrons and the cement samples three radioisotopes were induced: {sup 56}Mn, {sup 24}Na, and {sup 28}Al. (Author)

  1. Study by Monte Carlo methods of an explosive detection system using a D-D generator and Nal (Tl) detectors; Estudio mediante metodos Monte Carlo de un sistema de deteccion de explosivos utilizando un generador D-D y detectores de NaI (Tl)

    Energy Technology Data Exchange (ETDEWEB)

    Cevallos R, L. E.; Guzman G, K. A.; Gallego, E.; Garcia F, G. [Universidad Politecnica de Madrid, Escuela Tecnica Superior de Ingenieros Industriales, Departamento de Ingenieria Energetica, C. Jose Gutierrez Abascal 2, 28006 Madrid (Spain); Vega C, H. R., E-mail: lenin_cevallos@hotmail.com [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas, Zac. (Mexico)

    2017-10-15

    The detection of hidden explosive material is very important for national security. Using Monte Carlo methods, with the code MCNP6, several proposed configurations of a detection system with a Deuterium-Deuterium (D-D) generator, in conjunction with NaI (Tl) scintillation detectors, have been evaluated to intercept hidden explosives. The response of the system to various explosive samples such as Rdx and ammonium nitrate are analyzed as the main components of home-military explosives. The D-D generator produces fast neutrons of 2.5 MeV in a maximum field of 10{sup 10} n/s (Dd-110) which is surrounded with high density polyethylene in order to thermalized the fast neutrons making them interact with the sample inspected, giving rise to the emission of gamma rays that generates a characteristic spectrum of the elements that constitute it, being able in this way to determine its chemical composition and identify the type of substance. The necessary shielding is evaluated to estimate the admissible operation dose, with thicknesses of lead and borated polyethylene, in order to place it at some point of the Laboratory of Neutron Measurements of the Polytechnic University of Madrid where the shielding is optimal. The results show that its functionality is promising in the field of national security for the explosives inspection. (Author)

  2. Proceedings of the seventeenth national symposium on solid state nuclear track detectors and their applications: abstracts and souvenir

    International Nuclear Information System (INIS)

    Patel, Gaurang; Kishore, Sangeeta; Patel, Purvi

    2011-10-01

    The proceedings of the seventeenth national symposium on solid state nuclear track detectors and their applications (SSNTD-17) contains a number of research papers on different areas of solid state nuclear track detectors. It provides a common scientific platform to the scientists for sharing their knowledge and reviews the present state-of-art and advancements in the field of solid state nuclear track detectors and their applications and also some aspects of nuclear energy. Papers relevant to INIS are indexed separately

  3. A balloon-borne solid state cosmic X-ray detector

    International Nuclear Information System (INIS)

    Proctor, R.; Pietsch, W.; Reppin, C.

    1982-01-01

    On 9th May 1980 a MPI/AIT hard X-ray balloon payload successfully observed numerous cosmic X-ray sources. The payload consisted of a 2400 cm 2 Phoswich detector and a 114 cm 2 solid state detector. The solid state detector is described in this report. It consists of six intrinsic germanium planar crystals in a vacuum cryostat cooled by liquid nitrogen. The detector operates in the hard X-ray energy range of 20-150 keV and had in-flight a mean energy resolution of 2.75 keV at 60 keV. A hexagonal molybdenum collimator defined the field of view as approximately 4 0 fwhm. A CsI(Na) and plastic active shield and passive shielding provided background rejection. Mean background values of 1.3 X 10 -3 counts/(sec x cm 2 x keV) at 60 keV were obtained. (orig.)

  4. Solid track detectors used for the dating by thermoluminescence

    International Nuclear Information System (INIS)

    Miallier, D.

    1982-10-01

    A new α counting technic is presented in the field of the thermoluminescent dating method. It is based upon α particles registration in plastic detectors LR-115 Kodak in close contact with archeological or geological samples. The control of etching and counting conditions allowed to improve the usual precision of the detector. The following data are collected: α and β dose rates deposited by Uranium and Thorium series; an approximative value for the Uranium-Thorium ratio; spatial distribution of α emittors within samples and the radon escape rated. This method was used simultaneously with the ''quartz inclusion technic'' to date several samples: volcanic lava flows from the ''Chaine des Puys'' (Center France); the Butte de Clermont basaltic maar; a neolithic ''cardial'' pot-sherd and bricks from a minoaan palace (Mallia, Crete) [fr

  5. The calibration of the solid state nuclear track detector LR 115 for radon measurements

    CERN Document Server

    Gericke, C; Jönsson, G; Freyer, K; Treutler, H C; Enge, W

    1999-01-01

    An experimental calibration of indoor room and outdoor soil detector devices which are based on LR 115 as sensitive element has taken place at the Swedish Radiation Protection Institute in Stockholm (Sweden) in 1994 and 1996, at the Physikalisch-Technischen Bundesanstalt in Braunschweig (Germany) in 1997 and at the Umweltforschungszentrum Leipzig-Halle (Germany) in 1997. Special properties of the used solid state nuclear track detector (SSNTD) material LR 115 have been measured to define the application of the experimental calibration.

  6. Solid-State Neutron Multiplicity Counting System Using Commercial Off-the-Shelf Semiconductor Detectors

    Energy Technology Data Exchange (ETDEWEB)

    Rozhdestvenskyy, S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-08-09

    This work iterates on the first demonstration of a solid-state neutron multiplicity counting system developed at Lawrence Livermore National Laboratory by using commercial off-the-shelf detectors. The system was demonstrated to determine the mass of a californium-252 neutron source within 20% error requiring only one-hour measurement time with 20 cm2 of active detector area.

  7. Design and fabrication of a novel self-powered solid-state neutron detector

    Science.gov (United States)

    LiCausi, Nicholas

    There is a strong interest in intercepting special nuclear materials (SNM) at national and international borders and ports for homeland security applications. Detection of SNM such as U and Pu is often accomplished by sensing their natural or induced neutron emission. Such detector systems typically use thermal neutron detectors inside a plastic moderator. In order to achieve high detection efficiency gas filled detectors are often used; these detectors require high voltage bias for operation, which complicates the system when tens or hundreds of detectors are deployed. A better type of detector would be an inexpensive solid-state detector that can be mass-produced like any other computer chip. Research surrounding solid-state detectors has been underway since the late 1990's. A simple solid-state detector employs a planar solar-cell type p-n junction and a thin conversion material that converts incident thermal neutrons into detectable alpha-particles and 7Li ions. Existing work has typically used 6LiF or 10B as this conversion layer. Although a simple planar detector can act as a highly portable, low cost detector, it is limited to relatively low detection efficiency (˜10%). To increase the efficiency, 3D perforated p-i-n silicon devices were proposed. To get high efficiency, these detectors need to be biased, resulting in increased leakage current and hence detector noise. In this research, a new type of detector structure was proposed, designed and fabricated. Among several detector structures evaluated, a honeycomb-like silicon p-n structure was selected, which is filled with natural boron as the neutron converter. A silicon p+-n diode formed on the thin silicon wall of the honeycomb structure detects the energetic alpha-particles emitted from the boron conversion layer. The silicon detection layer is fabricated to be fully depleted with an integral step during the boron filling process. This novel feature results in a simplified fabrication process. Three

  8. Solid state nuclear track detectors kit for the use in teaching

    International Nuclear Information System (INIS)

    Khouri, M.T.F.C.; Koskinas, M.F.

    1988-11-01

    The kit intends to improve the possibilities in performing experiments of Nuclear Physics in Modern Physics laboratories of Physics Course introducing the solid state nuclear track detectors. In these materials the passage of heavily ionizing nuclear particles creates paths (tracks) that may be revealed and made visible in an optical microscope. By the help of the kit several experiments and/or demonstrations may be performed. The kit contains solid state nuclear track detectors unirradiated and irradiated, irradiated etched and unetched sheets: an alpha source of 241 Am and an instrution text with photomicrographs. To use the kit the laboratory must have an ordinary optical microscope. (author) [pt

  9. Isotopic exchange in a neutron-irradiated mixed-valence compound: Tl3(I) Tl(III)Cl6

    International Nuclear Information System (INIS)

    Fernandez Valverde, S.; Duplatre, G.

    1977-01-01

    The initial distribution of Tl(I) and Tl(III) species, and its change on heating, have been investigated in solid thermal neutron-irradiated Th 4 Cl 6 . An initial ratio of 5/1 for 204 Tl(I)/ 204 Tl(III) is found and this remains constant for integral gamma-doses of 3 to 12 MRad. The variation of the 204 Tl(III) fraction with temperature is found identical to that observed in labelled Tl 4 Cl 6 for which a genuine isotopic exchange has previously been described. It is concluded that the recoil species are rapidly converted, after the recoil processes, into stable ions

  10. The former tests realized to a personal neutron dosemeter based on solid nuclear tracks detector

    International Nuclear Information System (INIS)

    Camacho, M.E.; Tavera, L.; Balcazar, M.

    1997-01-01

    Due to the increase in the use of neutron radiation a personal neutron dosemeter based on solid nuclear tracks detector (DSTN) was designed and constructed. The personal dosemeter design consists of three arrangements. The first one consists of a plastic nuclear tracks detector (LR115 or CR39) in contact with a LiF pellet. The second one is the same that above but it placed among two cadmium pellets and, the third one is formed by the alone detector without converter neither neutron absorber. The three arrangements are placed inside a plastic porta detector hermetically closed to avoid the bottom produced by environmental radon whichever both detectors (LR115 and CR39) are sensitive. In this work the former tests realized to that dosemeter are presented. (Author)

  11. A study of the impact of radiation exposure on the uniformity of large CsI(Tl) crystals for the BaBar detector

    International Nuclear Information System (INIS)

    Hryn'ova, Tetiana; Kim, Peter; Kocian, Martin; Perl, Martin; Rogers, Howard; Schindler, Rafe H.; Wisniewski, William J.

    2004-01-01

    We describe an apparatus that allows simultaneous exposure of large CsI(Tl) crystals to ionizing radiation and precise measurement of the longitudinal changes in light yield of the crystals. We present herein the results from this device for exposures up to 10krad

  12. Measuring naturally occurring uranium in soil and minerals by analysing the 352 keV gamma-ray peak of 214Pb using a NaI(Tl)-detector

    International Nuclear Information System (INIS)

    Bezuidenhout, J.

    2013-01-01

    This article investigates the prospect of utilising the 351.9 keV gamma-ray of 214 Pb when determining the concentration of uranium. Soil samples were collected from various locations around South Africa and laboratory gamma ray spectra for each were obtained by means of a NaI(Tl)-detector (7.62×7.62 cm 2 ). The potassium, uranium and thorium concentrations where extracted by analysing gamma ray peaks that are associated with these radionuclides. Two separate uranium concentrations were extracted; one by means of the 214 Pb decay and the other one by means of the 214 Bi decay. These uranium concentrations were compared in terms of accuracies and detection limits. - Highlights: • Investigated a method to improve uranium concentrations measurements. • Expansion on an existing method that analyses naturally occurring radionuclides. • Utilise pill containers opposed to Marrinelli beakers. • Possible application to in situ measurements. • The method utilise NaI(Tl)-detectors with relative high efficiency

  13. An X-ray computed tomography demonstrator using a CZT solid-state detector

    International Nuclear Information System (INIS)

    Claesson, Th.; Kerek, A.; Molnar, J.; Novak, D.

    2002-01-01

    A demonstrator of Computed Tomography (CT) has been designed and built for educational purposes. The system is based on a solid-state CdZnTe detector and a standard PC. The mechanics of the system is controlled and data is acquired by programs written in LabVIEW. CT images are reconstructed using MATLAB programs

  14. Annealing effects on the charged particles registration characteristic of the CR-39 traces solid detector

    International Nuclear Information System (INIS)

    Correa, M.M.

    1989-10-01

    CR-39 trace solid detectors samples, previously exposed to alpha particles and fission fragments from a Cf-252 source, were submitted to a annealing treatment to study his effects on the characteristics of charged particle traces registration. (L.C.J.A.)

  15. Is the Spencer-Attix cavity equation applicable for solid-state detectors irradiated in megavoltage electron beams?

    International Nuclear Information System (INIS)

    Mobit, P.N.; Sandison, G.A.; Calgary Univ., AB

    2001-01-01

    The applicability of the Spencer-Attix cavity equation in determining absorbed doses in water using solid state detectors irradiated by megavoltage electron beams have been examined. The calculations were performed using the EGSnrc Monte Carlo code. This work is an extension of a recently published article examining the perturbation of dose by solid state detectors in megavoltage electron beams. (orig.)

  16. Development of a modular directional and spectral neutron detection system using solid-state detectors

    Energy Technology Data Exchange (ETDEWEB)

    Weltz, A., E-mail: weltza3@gmail.com; Torres, B.; McElwain, L.; Dahal, R.; Huang, J.; Bhat, I.; Lu, J.; Danon, Y.

    2015-08-21

    A detection system using room-temperature, microstructured solid-state thermal neutron detectors with very low leakage current has been developed at Rensselaer Polytechnic Institute (RPI) with the ability to provide positional and spectral information about an unknown neutron source. The Directional and Spectral Neutron Detection System (DSNDS) utilizes a set of small-but-scalable, zero-bias solid-state thermal neutron detectors which have demonstrated high thermal neutron efficiency and adequate gamma insensitivity. The DSNDS can gather spectral information about an unknown neutron source with a relatively small number of detectors, simplifying the detector electronics and minimizing cost; however, the DSNDS is modular in design, providing the capability to increase the detection efficiency and angular resolution. The system used in this paper was comprised of a stack of five high-density polyethylene (HDPE) disks with a thickness of 5 cm and a diameter of 30 cm, the middle disk containing 16 detectors positioned as one internal (moderated) and one external (unmoderated) ring of solid-state neutron detectors. These two detector rings provide the ability to determine the directionality of a neutron source. The system gathers spectral information about a neutron source in two ways: by measuring the relative responses of the internal ring of detectors as well as measuring the ratio of the internal-to-external detector responses. Experiments were performed with variable neutron spectra: a {sup 252}Cf spontaneous fission neutron source which was HDPE moderated, HDPE reflected, lead (Pb) shielded, and bare in order to benchmark the system for spectral sensitivity. Simulations were performed in order to characterize the neutron spectra corresponding to each of the source configurations and showed agreement with experimental measurements. The DSNDS demonstrates the ability to determine the relative angle of the source and the hardness of the neutron spectrum. By using the

  17. Doped Tl-1212 and Tl-1223 superconductors

    International Nuclear Information System (INIS)

    Eder, M.H.

    2001-09-01

    This work describes the preparation and characterization of thallium-lead-strontium-barium-calcium-(uranium)-copperoxide (Tl-1212, Tl-1223) high-temperature superconductors. The precursors were prepared via nitrate method. After calcination the oxidic powders were mixed with stoichiometric amounts of an Tl 2 O 3 , PbO, Er 2 O 3 and Gd 2 O 3 by milling and afterwards uniaxial compressed. Sintering was carried out in silver foils. X-ray diffractometry and high-resolution microscopy in combination with scanning electron microscopy (including EDAX) were used to study the influence of varying thallium/lead-, strontium/barium-, calcium/rare earth element ratios and the effect of uranium on the phase composition and microstructure of bulk superconductors. Furthermore the influence of the composition on the electrical and magnetical properties was studied. On phase pure Tl-1212 and Tl-1223 superconductors NMR-measurements were done. Small amounts of gadolinium and erbium instead of calcium and excess-uranium have a positive impact on the electrical and magnetical properties of the Tl-1223 superconductors. Higher amounts of these doping elements favor the Tl-1212 phase. Tl-1212 superconductors with varying thallium/lead- strontium/barium- and calcium/gadolinium ratios were prepared phasepure in wide range of doping. Transition temperatures up to 96 K were achieved. It was shown that lead has an oxidation number of +4 and thallium of +3. (author)

  18. Applications of CR-39 solid state nuclear track detector to ion beam diagnosis

    International Nuclear Information System (INIS)

    Kanasaki, Masato; Hattori, Atsuto; Oda, Keiji; Yamauchi, Tomoya; Fukuda, Yuji; Sakaki, Hironao; Nishiuchi, Mamiko; Kondo, Kiminori; Kurashima, Satoshi; Kamiya, Tomihiro

    2012-01-01

    CR-39 solid state nuclear track detector, which was developed for optical lens, has been applied for various field such as radon surveys, measurement of galactic cosmic ray, cell irradiation experiment and so on. The CR-39 detectors have the great advantages of being insensitive to high energy photons and electrons and capable of detecting only ions in the mixed fields such as laser driven relativistic plasmas. Though there are some analytical methods of CR-39 to diagnose ion beam, unfortunately, only few researchers in the field of plasma know the methods. This article looks at how to use CR-39 detectors and introduce the accomplishment of the joint study JAEA and Kobe Univ. for application of CR-39 detectors to ion beam diagnosis. (author)

  19. Charged particle spectroscopy with solid state nuclear track detectors

    International Nuclear Information System (INIS)

    Hunyadi, I.; Somogyi, G.

    1984-01-01

    Some of earlier and recent methods for differentiation of charged particles according to their energy, based on the use of polymeric etch-track detectors (CN, CA, PC and CR-39) are outlined. The principle of three track methods suitable for nuclear spectroscopy is discussed. These are based on the analysis of the diameter, surface size and shape of etch-track 'cones' produced by charged particles in polymers, after using shorter or longer chemical etching processes. Examples are presented from the results of the last decade in ATOMKI, Debrecen, Hungary, concerning the application of nuclear track spectroscopy to different low-energy nuclear reaction studies, angular distribution and excitation function measurements. These involve the study of (d,α) reaction on sup(14)N, sup(19)F and sup(27)Al nuclei, (sup(3)He,α) reactions on sup(15)N, (p,α) reaction on sup(27)Al and the process sup(12)C(sup(12)C, sup(8)Be)sup(16)O. (author)

  20. Scalability, Scintillation Readout and Charge Drift in a Kilogram Scale Solid Xenon Particle Detector

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, J. [Fermilab; Cease, H. [Fermilab; Jaskierny, W. F. [Fermilab; Markley, D. [Fermilab; Pahlka, R. B. [Fermilab; Balakishiyeva, D. [Florida U.; Saab, T. [Florida U.; Filipenko, M. [Erlangen - Nuremberg U., ECAP

    2014-10-23

    We report a demonstration of the scalability of optically transparent xenon in the solid phase for use as a particle detector above a kilogram scale. We employ a liquid nitrogen cooled cryostat combined with a xenon purification and chiller system to measure the scintillation light output and electron drift speed from both the solid and liquid phases of xenon. Scintillation light output from sealed radioactive sources is measured by a set of high quantum efficiency photomultiplier tubes suitable for cryogenic applications. We observed a reduced amount of photons in solid phase compared to that in liquid phase. We used a conventional time projection chamber system to measure the electron drift time in a kilogram of solid xenon and observed faster electron drift speed in the solid phase xenon compared to that in the liquid phase.

  1. Calibration factor determination for solid nuclear track detectors CR-39 type exposed to Rn-222

    International Nuclear Information System (INIS)

    Cazula, Camila Dias; Campos, Marcia Pires de; Mazzilli, Barbara Paci

    2014-01-01

    In the detection method with solid nuclear track detector, when a heavy particle rests on the detector surface, causes a breakdown in their molecular structure forming a trace. One of the typical applications of these detectors is the measurement of the concentration of Rn -222 in air, a noble radioactive gas, part of the U-238 series, emitting alpha particles and important in epidemiological studies to protect individuals from natural radiation. To determine the concentration of Rn -222 in the air in a room is necessary to know the density of lines (traces / cm 2 ) on the detector surface, the exposure time and the calibration factor. The determination of the calibration factor for CR-39 detectors was taken from the exposure of these to a known concentration of Rn-222. Therefore, the detectors were placed inside a cell of Lucas adapted and subsequently exposed to a concentration of Rn-222 15 kBq / m 3 , by means of the apparatus RN-150 Pylon Electronics Incorporation, which has a source of Ra-226 and releases known concentrations of Rn-222. Six calibration factor determinations were performed, the average value obtained was 0.0534 ±0.0021 (traces / cm 2 per Bq / m 3 day). The results are consistent with literature values for the same type of detector and showed good reproducibility

  2. Calculations of Total and Differential Solid Angles for a Proton Recoil Solid State Detector

    Energy Technology Data Exchange (ETDEWEB)

    Konijn, J; Lauber, A; Tollander, B

    1963-08-15

    The solid angles have been computed for a proton recoil counter consisting of a circular hydrogenous foil viewed by an isotropic neutron point source at different distances from the target foil. Tables are given for the total subtended solid angle as well as the differential energy distribution function of the proton recoil spectrum. The influence of finite foil thickness has also been studied.

  3. Development of analog solid-state photo-detectors for Positron Emission Tomography

    Energy Technology Data Exchange (ETDEWEB)

    Bisogni, Maria Giuseppina, E-mail: giuseppina.bisogni@pi.infn.it; Morrocchi, Matteo

    2016-02-11

    Solid-state photo-detectors are one of the main innovations of past century in the field of sensors. First produced in the early forties with the invention of the p–n junction in silicon and the study of its optical properties, photo-detectors received a major boost in the sixties when the p-i-n (PIN) photodiode was developed and successfully used in several applications. The development of devices with internal gain, avalanche photodiodes (APD) first and then Geiger-mode avalanche photodiodes, named single photon avalanche diode (SPAD), leads to a substantial improvement in sensitivity and allowed single photon detection. Later on, thousands of SPADs have been assembled in arrays of few millimeters squared (named SiPM, silicon photo-multiplier) with single photon resolution. The high internal gain of SiPMs, together with other features peculiar of the silicon technology like compactness, speed and compatibility with magnetic fields, promoted SiPMs as the principal photo-detector competitor of photomultipliers in many applications from radiation detection to medical imaging. This paper provides a review of the properties of analog solid-state photo-detectors. Particular emphasis is given to latest advances on Positron Emission Tomography instrumentation boosted by the adoption of the silicon photo-detectors as an alternative to photomultiplier tubes (PMTs). Special attention is dedicated to the SiPMs, which are playing a key role in the development of innovative scanners.

  4. Development of analog solid-state photo-detectors for Positron Emission Tomography

    International Nuclear Information System (INIS)

    Bisogni, Maria Giuseppina; Morrocchi, Matteo

    2016-01-01

    Solid-state photo-detectors are one of the main innovations of past century in the field of sensors. First produced in the early forties with the invention of the p–n junction in silicon and the study of its optical properties, photo-detectors received a major boost in the sixties when the p-i-n (PIN) photodiode was developed and successfully used in several applications. The development of devices with internal gain, avalanche photodiodes (APD) first and then Geiger-mode avalanche photodiodes, named single photon avalanche diode (SPAD), leads to a substantial improvement in sensitivity and allowed single photon detection. Later on, thousands of SPADs have been assembled in arrays of few millimeters squared (named SiPM, silicon photo-multiplier) with single photon resolution. The high internal gain of SiPMs, together with other features peculiar of the silicon technology like compactness, speed and compatibility with magnetic fields, promoted SiPMs as the principal photo-detector competitor of photomultipliers in many applications from radiation detection to medical imaging. This paper provides a review of the properties of analog solid-state photo-detectors. Particular emphasis is given to latest advances on Positron Emission Tomography instrumentation boosted by the adoption of the silicon photo-detectors as an alternative to photomultiplier tubes (PMTs). Special attention is dedicated to the SiPMs, which are playing a key role in the development of innovative scanners.

  5. Measurement of fission track of uranium particle by solid state nuclear track detector

    International Nuclear Information System (INIS)

    Son, S. C.; Pyo, H. W.; Ji, K. Y.; Kim, W. H.

    2002-01-01

    In this study, we discussed results of the measurement of fission tracks for the uranium containing particles by solid state nuclear track detector. Uranium containing silica and uranium oxide particles were prepared by uranium sorption onto silica powder in weak acidic medium and laser ablation on uranium pellet, respectively. Fission tracks for the uranium containing silica and uranium oxide particles were detected on Lexan plastic detector. It was found that the fission track size and shapes depend on the particle size uranium content in particles. Correlation of uranium particle diameter with fission track radius was also discussed

  6. Properties of polymer foils used as solid-state track detectors

    International Nuclear Information System (INIS)

    Spurny, F.

    1973-05-01

    Polymer foils were studied with a view to their application as solid-state alpha track detectors. The detection efficiency was determined as was its alpha energy dependence and the quality of the surface and the natural background of the foils were evaluated. The kinetics of etching was studied in three selected type of foils. Characteristic constants for the selected foils and methods of etching were calculated. The possible applications of the foils as track detectors are discussed and the effect is dealt with of the selected foil and of the method of chemical etching on the foil applicability in nuclear sciences, especially in fast neutron dosimetry and in alpha spectrometry. (author)

  7. New software library of geometrical primitives for modelling of solids used in Monte Carlo detector simulations

    CERN Multimedia

    CERN. Geneva

    2012-01-01

    We present our effort for the creation of a new software library of geometrical primitives, which are used for solid modelling in Monte Carlo detector simulations. We plan to replace and unify current geometrical primitive classes in the CERN software projects Geant4 and ROOT with this library. Each solid is represented by a C++ class with methods suited for measuring distances of particles from the surface of a solid and for determination as to whether the particles are located inside, outside or on the surface of the solid. We use numerical tolerance for determining whether the particles are located on the surface. The class methods also contain basic support for visualization. We use dedicated test suites for validation of the shape codes. These include also special performance and numerical value comparison tests for help with analysis of possible candidates of class methods as well as to verify that our new implementation proposals were designed and implemented properly. Currently, bridge classes are u...

  8. Development of alpha spectroscopy method with solid state nuclear track detector using aluminium thin films

    Energy Technology Data Exchange (ETDEWEB)

    Dwaikat, N., E-mail: ndwaikat@kfupm.edu.sa [King Fahd University of Petroleum and Minerals, College of Sciences, Department of Physics, Dhahran 31261 (Saudi Arabia)

    2015-10-15

    This work presents the development of alpha spectroscopy method with Solid-state nuclear track detectors using aluminum thin films. The resolution of this method is high, and it is able to discriminate between alpha particles at different incident energy. It can measure the exact number of alpha particles at specific energy without needing a calibration of alpha track diameter versus alpha energy. This method was tested by using Cf-252 alpha standard source at energies 5.11 MeV, 3.86 MeV and 2.7 MeV, which produced by the variation of detector -standard source distance. On front side, two detectors were covered with two Aluminum thin films and the third detector was kept uncovered. The thickness of Aluminum thin films was selected carefully (using SRIM 2013) such that one of the films will block the lower two alpha particles (3.86 MeV and 2.7 MeV) and the alpha particles at higher energy (5.11 MeV) can penetrate the film and reach the detectors surface. The second thin film will block alpha particles at lower energy of 2.7 MeV and allow alpha particles at higher two energies (5.11 MeV and 3.86 MeV) to penetrate and produce tracks. For uncovered detector, alpha particles at three different energies can produce tracks on it. For quality assurance and accuracy, the detectors were mounted on thick enough copper substrates to block exposure from the backside. The tracks on the first detector are due to alpha particles at energy of 5.11 MeV. The difference between the tracks number on the first detector and the tracks number on the second detector is due to alpha particles at energy of 3.8 MeV. Finally, by subtracting the tracks number on the second detector from the tracks number on the third detector (uncovered), we can find the tracks number due to alpha particles at energy 2.7 MeV. After knowing the efficiency calibration factor, we can exactly calculate the activity of standard source. (Author)

  9. Development of alpha spectroscopy method with solid state nuclear track detector using aluminium thin films

    International Nuclear Information System (INIS)

    Dwaikat, N.

    2015-10-01

    This work presents the development of alpha spectroscopy method with Solid-state nuclear track detectors using aluminum thin films. The resolution of this method is high, and it is able to discriminate between alpha particles at different incident energy. It can measure the exact number of alpha particles at specific energy without needing a calibration of alpha track diameter versus alpha energy. This method was tested by using Cf-252 alpha standard source at energies 5.11 MeV, 3.86 MeV and 2.7 MeV, which produced by the variation of detector -standard source distance. On front side, two detectors were covered with two Aluminum thin films and the third detector was kept uncovered. The thickness of Aluminum thin films was selected carefully (using SRIM 2013) such that one of the films will block the lower two alpha particles (3.86 MeV and 2.7 MeV) and the alpha particles at higher energy (5.11 MeV) can penetrate the film and reach the detectors surface. The second thin film will block alpha particles at lower energy of 2.7 MeV and allow alpha particles at higher two energies (5.11 MeV and 3.86 MeV) to penetrate and produce tracks. For uncovered detector, alpha particles at three different energies can produce tracks on it. For quality assurance and accuracy, the detectors were mounted on thick enough copper substrates to block exposure from the backside. The tracks on the first detector are due to alpha particles at energy of 5.11 MeV. The difference between the tracks number on the first detector and the tracks number on the second detector is due to alpha particles at energy of 3.8 MeV. Finally, by subtracting the tracks number on the second detector from the tracks number on the third detector (uncovered), we can find the tracks number due to alpha particles at energy 2.7 MeV. After knowing the efficiency calibration factor, we can exactly calculate the activity of standard source. (Author)

  10. Charged projectile spectrometry using solid-state nuclear track detector of the PM-355 type

    Directory of Open Access Journals (Sweden)

    Malinowska Aneta

    2015-09-01

    Full Text Available To use effectively any radiation detector in high-temperature plasma experiments, it must have a lot of benefits and fulfill a number of requirements. The most important are: a high energy resolution, linearity over a wide range of recorded particle energy, high detection efficiency for these particles, a long lifetime and resistance to harsh conditions existing in plasma experiments and so on. Solid-state nuclear track detectors have been used in our laboratory in plasma experiments for many years, but recently we have made an attempt to use these detectors in spectroscopic measurements performed on some plasma facilities. This paper presents a method that we used to elaborate etched track diameters to evaluate the incident projectile energy magnitude. The method is based on the data obtained from a semiautomatic track scanning system that selects tracks according to two parameters, track diameter and its mean gray level.

  11. Harsh-Environment Solid-State Gamma Detector for Down-hole Gas and Oil Exploration

    International Nuclear Information System (INIS)

    Peter Sandvik; Stanislav Soloviev; Emad Andarawis; Ho-Young Cha; Jim Rose; Kevin Durocher; Robert Lyons; Bob Pieciuk; Jim Williams; David O'Connor

    2007-01-01

    The goal of this program was to develop a revolutionary solid-state gamma-ray detector suitable for use in down-hole gas and oil exploration. This advanced detector would employ wide-bandgap semiconductor technology to extend the gamma sensor's temperature capability up to 200 C as well as extended reliability, which significantly exceeds current designs based on photomultiplier tubes. In Phase II, project tasks were focused on optimization of the final APD design, growing and characterizing the full scintillator crystals of the selected composition, arranging the APD device packaging, developing the needed optical coupling between scintillator and APD, and characterizing the combined elements as a full detector system preparing for commercialization. What follows is a summary report from the second 18-month phase of this program

  12. Harsh-Environment Solid-State Gamma Detector for Down-hole Gas and Oil Exploration

    Energy Technology Data Exchange (ETDEWEB)

    Peter Sandvik; Stanislav Soloviev; Emad Andarawis; Ho-Young Cha; Jim Rose; Kevin Durocher; Robert Lyons; Bob Pieciuk; Jim Williams; David O' Connor

    2007-08-10

    The goal of this program was to develop a revolutionary solid-state gamma-ray detector suitable for use in down-hole gas and oil exploration. This advanced detector would employ wide-bandgap semiconductor technology to extend the gamma sensor's temperature capability up to 200 C as well as extended reliability, which significantly exceeds current designs based on photomultiplier tubes. In Phase II, project tasks were focused on optimization of the final APD design, growing and characterizing the full scintillator crystals of the selected composition, arranging the APD device packaging, developing the needed optical coupling between scintillator and APD, and characterizing the combined elements as a full detector system preparing for commercialization. What follows is a summary report from the second 18-month phase of this program.

  13. Thermal neutron detection by means of an organic solid-state track detector

    International Nuclear Information System (INIS)

    Doerschel, B.; Streubel, G.

    1979-01-01

    Thermal neutrons can be detected by means of organic solid-state track detectors if they are combined with radiators in which charged secondary particles are produced in neutron interaction processes. The secondary particles can produce etchable tracks in the detector material. For thermal neutron fluence determination from the track densities, the thermal neutron sensitivity was calculated for cellulose triacetate detectors with LiF radiators, taking into account energy and angular distribution of the alpha particles produced in the LiF radiator. This value is in good agreement with the sensitivity measured during irradiation in different neutron fields if corrections are considered the production of etchable or visuable tracks. Measuring range and measuring accuracy meet the requirements of thermal neutron detection in personnel dosimetry. Possibilities of extending the measuring range are discussed. (author)

  14. Fast neutron detection by means of an organic solid state track detector

    International Nuclear Information System (INIS)

    Doerschel, B.; Streubel, G.

    1980-01-01

    Solid state track detectors consisting of cellulose triacetate foils are appropriate for measuring the fast neutron fluence without applying external radiators. Detector sensitivity has been determined as a function of neutron energy by performing irradiations with various neutron sources and monoenergetic neutrons of different energies. A comparison with theoretical results given in the literature for a simple model of track recording has shown sufficient agreement. The measuring errors and the influence of spectral changes in the neutron field on detector response are discussed for the studied method of fluence measurement. By means of these errors the measuring range has been determined for well defined irradiation conditions, taking into account spectral changes in the neutron field. (author)

  15. Uranium analysis by neutron induced fissionography method using solid state nuclear track detectors

    International Nuclear Information System (INIS)

    Akyuez, T.; Tretyakova, S. P.; Guezel, T.; Akyuz, S.

    1999-01-01

    In this study total twenty samples (eight reference materials and twelve sediment samples) were analysed for their uranium content which is in the range of 1-17 μg/g, by neutron induced fissionography (NIF) method using solid state nuclear track detectors (SSNTDs) in comparison with the results of neutron activation analysis (NAA), delayed neutron counting (DNC) technique or fluorometric method. It is found that NIF method using SSNTDs is very sensitive for analysis of uranium

  16. Uranium analysis by neutron induced fissionography method using solid state nuclear track detectors

    CERN Document Server

    Akyuez, T; Guezel, T; Akyuz, S

    1999-01-01

    In this study total twenty samples (eight reference materials and twelve sediment samples) were analysed for their uranium content which is in the range of 1-17 mu g/g, by neutron induced fissionography (NIF) method using solid state nuclear track detectors (SSNTDs) in comparison with the results of neutron activation analysis (NAA), delayed neutron counting (DNC) technique or fluorometric method. It is found that NIF method using SSNTDs is very sensitive for analysis of uranium.

  17. Solid Angle Computations for a Circular Radiator and a Circular Detector

    Energy Technology Data Exchange (ETDEWEB)

    Konijn, J; Tollander, B

    1963-02-15

    The problem of particle detection, when using an isotropic neutron point source at different distances from a circular target or a radioactive source as seen by a circular detector, e. g. a solid state counter, is dealt with. Tables are given for different distances of the source when the reaction at the target has an isotropic or a cosine angular distribution in the laboratory system.

  18. Characterization of the polymer Durolon as a solid state nuclear track detector

    International Nuclear Information System (INIS)

    Pugliesi, Fabio

    2008-01-01

    The polymer Durolon has been characterized as a solid state nuclear track detector. In these detectors a track, resulting from the damages in its molecular structure, induced by a heavy charged particle, is the testimony of the passage of the particle through the polymer. In order to characterize the Durolon the track diameter, track production rate, light transmission through the polymer and the critical angle of incidence of the particle have been studied. The main objective of such studies was to provide the necessary subsidies to understand the information registered. The damages have been induced by alpha particles from the nuclear reaction 10 B(n,α) 7 Li, by irradiating a boron screen in a thermal neutron field from an experimental facility installed in the beam-hole 08 of the IEA-R1 nuclear research reactor of IPEN-CNEN/SP. The study of the parameters have been performed by using a digital system developed in the present work. Its use has provided a higher quality and quickness regarding data acquisition and data analysis as well as the opportunity to quantify several other parameters regarding the imaging formation theory in solid state nuclear track detectors. The characteristics of the Durolon have been compared with the ones of two other detectors Makrofol-E and Makrofol-DE and have demonstrated its potentiality to use. (author)

  19. NaI(Tl) electron energy resolution

    CERN Document Server

    Mengesha, W

    2002-01-01

    NaI(Tl) electron energy resolution eta sub e was measured using the Modified Compton Coincidence Technique (MCCT). The MCCT allowed detection of nearly monoenergetic internal electrons resulting from the scattering of incident 662 keV gamma rays within a primary NaI(Tl) detector. Scattered gamma rays were detected using a secondary HPGe detector in a coincidence mode. Measurements were carried out for electron energies ranging from 16 to 438 keV, by varying the scattering angle. Measured HPGe coincidence spectra were deconvolved to determine the scattered energy spectra from the NaI(Tl) detector. Subsequently, the NaI(Tl) electron energy spectra were determined by subtracting the energy of scattered spectra from the incident source energy (662 keV). Using chi-squared minimization, iterative deconvolution of the internal electron energy spectra from the measured NaI(Tl) spectra was then used to determine eta sub e at the electron energy of interest. eta sub e values determined using this technique represent va...

  20. Absolute efficiency calibration of 6LiF-based solid state thermal neutron detectors

    Science.gov (United States)

    Finocchiaro, Paolo; Cosentino, Luigi; Lo Meo, Sergio; Nolte, Ralf; Radeck, Desiree

    2018-03-01

    The demand for new thermal neutron detectors as an alternative to 3He tubes in research, industrial, safety and homeland security applications, is growing. These needs have triggered research and development activities about new generations of thermal neutron detectors, characterized by reasonable efficiency and gamma rejection comparable to 3He tubes. In this paper we show the state of the art of a promising low-cost technique, based on commercial solid state silicon detectors coupled with thin neutron converter layers of 6LiF deposited onto carbon fiber substrates. A few configurations were studied with the GEANT4 simulation code, and the intrinsic efficiency of the corresponding detectors was calibrated at the PTB Thermal Neutron Calibration Facility. The results show that the measured intrinsic detection efficiency is well reproduced by the simulations, therefore validating the simulation tool in view of new designs. These neutron detectors have also been tested at neutron beam facilities like ISIS (Rutherford Appleton Laboratory, UK) and n_TOF (CERN) where a few samples are already in operation for beam flux and 2D profile measurements. Forthcoming applications are foreseen for the online monitoring of spent nuclear fuel casks in interim storage sites.

  1. Filter-fluorescer x-ray spectrometer using solid state detectors for γ-ray background reduction

    International Nuclear Information System (INIS)

    Yokoi, Takashi; Kitagawa, Yoneyoshi; Shiraga, Hiroyuki; Matsunaga, Hirohide; Kato, Yoshiaki; Yamanaka, Chiyoe.

    1986-01-01

    Filter-fluorescer x-ray spectrometer using solid state photo-detectors instead of the photomultiplier tubes in order to reduce the γ-ray background noise is reported. A significant reduction of the γ-ray background noise is expected, because solid state photo-detectors are very small in size compared with the photomultiplier tubes. It has been confirmed that the γ-ray background is reduced in the target irradiation experiments with the Gekko MII glass laser. (author)

  2. Study of tracking detector of NEMO3 experiment - simulation of the measurement of the ultra low {sup 208}Tl radioactivity in the source foils used as neutrinoless double beta decay emitters in NEMO3 experiment; Etude du detecteur de traces de l'experience NEMO3. Simulation de la mesure de l'ultra-faible radioactivite en {sup 208}Tl des sources de l'experience NEMO3 candidates a la double desintegration {beta} sans emission de neutrino

    Energy Technology Data Exchange (ETDEWEB)

    Errahmane, K

    2001-04-01

    The purpose of NEMO3 experiment is the research of the neutrinoless double beta decay. This low energy process can sign the massive and Majorana nature of neutrino. This experiment, with a very low radioactive background and containing 10 kg of enriched isotopes, studies mainly {sup 100}Mo. Installed at the Frejus underground laboratory, NEMO3 is a cylindrical detector, which consists in very thin central source foils, in a tracking detector made up of vertical drift cells operating in Geiger mode, in a calorimeter and in a suitable shielding. This thesis is divided in two different parts. The first part is a full study of the features of the tracking detector. With a prototype composed of 9 drift cells, we characterised the longitudinal and transverse reconstruction of position of the ionisation created by a LASER. With the first 3 modules under operation, we used radioactive external neutron sources to measure the transverse resolution of ionisation position in a drift cell for high energy electrons. To study the vertex reconstruction on the source foil, sources of {sup 207}Bi, which produced conversion electrons, were used inside the 3 modules. The second part of this thesis, we show, with simulations, that we can measure, with NEMO3 detector itself, the ultra low level of contamination in {sup 208}Tl of the source foil, which comes from the natural radioactive chain of thorium. Using electron-photons channels, we can obtain the {sup 208}Tl activity in the sources. With an analysis on the energy and on the time of flight of particles, NEMO3 is able to reach a sensitivity of 20{mu}Bq/kg after only 2 months of measurement. This sensitivity is the maximum {sup 208}Tl activity, which we accepted for the sources in the NEMO3 proposal. (author)

  3. Measurement of conversion coefficients in 208Tl

    International Nuclear Information System (INIS)

    Wendling, F.

    1976-06-01

    A electron spectrometer composed by a Li drifted Si detector and a uniform magnetic field was constructed. The magnetic field is used to focus the electrons on the detector and to filter the other radiations. After the construction the instrument was calibrated in absolute eficience and was used together with a Ge(Li) spectrometer also calibrated, in the measurement of internal conversion coeficients of the 433 and 453 keV transitions in 208 Tl [pt

  4. Detection of gamma-neutron radiation by solid-state scintillation detectors. Detection of gamma-neutron radiation by novel solid-state scintillation detectors

    Energy Technology Data Exchange (ETDEWEB)

    Ryzhikov, V.; Grinyov, B.; Piven, L.; Onyshchenko, G.; Sidletskiy, O. [Institute for Scintillation Materials of the NAS of Ukraine, Kharkov, (Ukraine); Naydenov, S. [Institute for Single Crystals of the National Academy of Sciences of Ukraine, Kharkov, (Ukraine); Pochet, T. [DETEC-Europe, Vannes (France); Smith, C. [Naval Postgraduate School, Monterey, CA (United States)

    2015-07-01

    It is known that solid-state scintillators can be used for detection of both gamma radiation and neutron flux. In the past, neutron detection efficiencies of such solid-state scintillators did not exceed 5-7%. At the same time it is known that the detection efficiency of the gamma-neutron radiation characteristic of nuclear fissionable materials is by an order of magnitude higher than the efficiency of detection of neutron fluxes alone. Thus, an important objective is the creation of detection systems that are both highly efficient in gamma-neutron detection and also capable of exhibiting high gamma suppression for use in the role of detection of neutron radiation. In this work, we present the results of our experimental and theoretical studies on the detection efficiency of fast neutrons from a {sup 239}Pu-Be source by the heavy oxide scintillators BGO, GSO, CWO and ZWO, as well as ZnSe(Te, O). The most probable mechanism of fast neutron interaction with nuclei of heavy oxide scintillators is the inelastic scattering (n, n'γ) reaction. In our work, fast neutron detection efficiencies were determined by the method of internal counting of gamma-quanta that emerge in the scintillator from (n, n''γ) reactions on scintillator nuclei with the resulting gamma energies of ∼20-300 keV. The measured efficiency of neutron detection for the scintillation crystals we considered was ∼40-50 %. The present work included a detailed analysis of detection efficiency as a function of detector and area of the working surface, as well as a search for new ways to create larger-sized detectors of lower cost. As a result of our studies, we have found an unusual dependence of fast neutron detection efficiency upon thickness of the oxide scintillators. An explanation for this anomaly may involve the competition of two factors that accompany inelastic scattering on the heavy atomic nuclei. The transformation of the energy spectrum of neutrons involved in the (n, n

  5. Technical aspects in the obtention of tissue autoradiography using solid state nuclear track detectors

    International Nuclear Information System (INIS)

    Saint Martin, Gisela; Bernaola, Omar A.; Pozzi, Emiliano; Thorp, Silvia; Cabrini, Romulo L.; Tomasi, V.H.

    2007-01-01

    The autoradiography images produced in solid state nuclear track detectors by heavy ions originated in tissue provide relevant information about the spatial biodistribution of heavy particle emitters. Some preliminary aspects of the autoradiography technique are evaluated by two experiments which are in progress, using Lexan and CR 39 foils as solid state nuclear track detectors. In the first case, a tissue sample from rat kidney intoxicated with UO 2 (NO 3 ) 2 was embedded in paraffin and put in contact with a 1 mm thick CR 39 foil. After a two months exposure the foil was chemically developed resulting in scarce tracks. A satisfactory image cannot be obtained in these conditions. More prolonged exposure time is needed to obtain better images of such samples. The second experience consisted in the irradiation of fresh kidney tissue slices from healthy rats in contact with 250 μm thick Lexan foils, in a thermal neutrons flux. The irradiation was performed at the RA-3 facility of the Ezeiza Atomic Center (CAE). The contribution to image produced by tracks of particles due to reactions between neutrons and tissue elements (i.e. 14 N) was evaluated. The etching conditions should be modified in order to desensitize the detector material. (author) [es

  6. Calibration of track detectors and measurement of radon exhalation rate from solid samples

    International Nuclear Information System (INIS)

    Singh, Ajay Kumar; Jojo, P.J.; Prasad, Rajendra; Khan, A.J.; Ramachandran, T.V.

    1997-01-01

    CR-39 and LR-115 type II track detectors to be used for radon exhalation measurements have been calibrated. The configurations fitted with detectors in Can technique in the open cup mode are cylindrical plastic cup (PC) and conical plastic cup (CPC). The experiment was performed in radon exposure chamber having monodisperse aerosols of 0.2 μm size, to find the relationship between track density and the radon concentration. The calibration factors for PC and CPC type dosimeters with LR-115 type II detector were found to be 0.056 and 0.083 tracks cm -2 d -1 (Bqm -3 ) -1 respectively, while with CR-39 detector the values were 0.149 and 0.150 tracks cm -2 d -1 (Bq m -3 ) -1 . Employing the Can technique, measurements of exhalation rates from solid samples used as construction materials, are undertaken. Radon exhalation rate is found to be minimum in cement samples while in fly ash it is not enhanced as compared to coal samples. (author)

  7. Mapping of uranium and thorium in radioactive rocks using nuclear track solid detectors

    International Nuclear Information System (INIS)

    Bouch, C.M.

    1982-01-01

    α-Autoradiography and studies of induced fission in a research nuclear reactor (IEA-R1, IPEN, Sao Paulo) were done, employing Solid-State Nuclear Track detectors, in order to study the distribution of α-emitters, U and Th in rocks. Polished sections of rocks were prepared and photographed. Etching conditions were studied in order to adapt the detectors to the studies of microdistribution and macrodistribution of tracks. Polycarbonate foils (Bayer, Makrofol) were chosen as fission-fragments detectors and the technique of fission induced with reactor neutrons to obtain the distribution of U and Th were studied. Uranium and thorium standards evaporated on the surface of the detectors, as well as thorite and uraninite grains, were irradiated in order to measure the integrated flux of neutrons, the effective cross sections for fission with reactor neutrons for 232 Th(0,05b) and 238 U(0,30b) and to study the contribution of 238 U fission in thorium mapping. A technique for determination of uranium and thorium in minerals was studied and applied to Mica, for which were determined the contents of 4,2 ppb U e 58 ppb Th. (Author) [pt

  8. Detection of boron in metal alloys with solid state nuclear track detector by neutron induced autoradiography

    International Nuclear Information System (INIS)

    Ali Nabipour; Hosseini, A.; Afarideh, H.

    2002-01-01

    Neutron induced autoradiography is very useful technique for detection as well as measurement of Boron densities in metal alloys. The method is relatively simple and quite sensitive in comparison with other techniques with resolution in the range of PPM. Using this technique with it is also possible to investigate microscopic scattering of Boron in metal alloys. In comparison with most techniques neutron induced autoradiography has its own difficulties and limitations. In this research measurement of Boron densities and investigation of that diffusion in metal alloys has been carried out. A flat nicely polished Boron doped metal samples is covered with a track detecting plastic (CR-39 solid state nuclear track detector) and exposed to thermal neutron dose. After irradiation the plastic detector have been removed and put in an etching solution. Since the diffusion rate of corrosive solution in those area, which heavy ions have been, produces as the result of nuclear reaction with thermal neutron are more than the other areas, some cavities are formed. The diameter of cavities or tracks cross section are increased with increasing the etching time, to some extent that it is possible to observe the cavities with optical microscopes. The density of tracks on the detector surface is directly related to the Boron concentration in the sample and thermal neutron dose. So by measuring the number of tracks on surface of the detector it would possible to calculate the concentration of Boron in metal samples. (Author)

  9. Fission distribution measurements of Atucha's fuel pellets with solid state track detectors

    International Nuclear Information System (INIS)

    Ricabarra, M.D. Bovisio de; Waisman, Dina.

    1979-08-01

    Distribution of fissions in a UO 2 rod has been measured by means of solid state detectors. Mica muscovite and Makrofol-N detectors were used in the experiment. The merits of mica muscovite relative to the Makrofol-N for the detection of fission fragments have been verified. However both fission track detectors closely agree (0,5%) in the final fission distribution of the UO 2 rod. Sensitivity of the detectors shows to be linear in the range between 50.000and 360.000 fission tracks per square centimeter. Due to the high spatial resolution this method is better than any other technique. Determination were made in UO 2 pellets similar to the fuel element of the Atucha reactor. The average fission rate in the rod has been measured within 0,8% error, and provides an accurate determination for the distribution of fissions in the rod wich is needed for the determination of energy liberated per fission in the natural uranium rod.(author) [es

  10. Evaluation study between the chemical and electrochemical etching for solid state nuclear track detectors

    International Nuclear Information System (INIS)

    Ramos, S.; Espinosa, G.; Golzarri, J.I.

    1991-01-01

    Since there are several methods of etching in the solid state nuclear track detectors (SSNTD) it is necessary to know which gives the best results for a specific problem. The purpose of this work is to analyze and compare both the chemical etching and the electrochemical etching. The SSNTD has a preferential response to certain kinds of particles and energies, according to the material used as detector. On the other hand the efficiency is a function of the incidence angle of the radiation and some other parameters such as temperature, concentration and type of solvent used in the etching process, and the method used for the etching. Therefore, it is necessary to extend as much as possible our knowledge of such parameters in order to choose the more efficient one for a specific problem

  11. The measurement of radon and thoron by solid state nuclear track detectors

    International Nuclear Information System (INIS)

    Khan, H.A.; Akhwand, R.A.; Bukhari, K.M.; Saddarudin, A.

    1976-01-01

    Experiments have been conducted to study a) the development and annealing properties of the latent damage trails produced by radon/thoron alpha particles in plastic Solid State Nuclear Track Detectors (SSNTDs), and b) the diffusion properties of radon and thoron in various media by using SSNTDs. The information thus obtained has been employed for a) the optimization of the conditions for the construction of radon/thoron dosimeters for uranium/thorium mines, and b) the use of SSNTDs for the prospection and estimation of uranium and thorium. The results indicate that these gases can diffuse even through rocks, and cellulose nitrate detectors, LR-115 and CA80-15, can be profitably employed in dosimetry, prospection, and for the discrimination between uranium and thorium deposits. (orig.) [de

  12. International comparison of radon measurement using solid state nuclear track detectors

    International Nuclear Information System (INIS)

    Hu Dan; Yang Weigen; Song Jianfeng

    2011-01-01

    It introduces the radon measurements international comparison using solid state track detectors among Zhejiang Environmental Radiation Monitoring Center (RMTC), Japan Chemical Analysis Center (JCAC) and National Institute for Radiological Protection of China CDC (NIRP). The results of the international comparison show that: Compared to the reference values, the measurements' relative deviations of detectors from 3 labs were 2%∼22%, which were exposed in radon chambers with different radon concentration, while the measurements' relative deviations were 0.5%∼13% when exposed in the environment. The measurement's relative deviations of RMTC were 5%∼3% in radon chambers and 0.5%∼9% in the environment, the results met requirements of the relative standards both at home and abroad. (authors)

  13. Intrinsic thermoluminescence of NaCl:Tl in UV dosimetry

    International Nuclear Information System (INIS)

    Barghare, S.P.; Joshi, R.V.; Joshi, T.R.; Kathuria, S.P.

    1982-01-01

    NaCl:Tl(T) phosphor is found to have high intrinsic thermoluminescence (TL) sensitivity to 253.7 nm UV-radiation. The dosimetric glow peak II grows sublinearly with increase in UV dose in the range 10 3 to 10 6 JM -2 . The other requirements of an efficient dosimeter material such as high storage stability, matching of the spectral response of detector tube and TL-emission from phosphor, reproducibility, desirable size and shape, easy availability in powder, pellet and crystal forms at cheaper rates, and repeated re-usability of the same phosphor without much difficulty, etc., are additional factors which strengthen the claim of NaCl:Tl(T) phosphor as UV dosimetric material. It is proposed that present NaCl:Tl(T) material is suitable TL-phosphor for UV dosimetry in the range 10 3 to 10 6 JM -2 . (author)

  14. Past and future application of solid-state detectors in manned spaceflight

    International Nuclear Information System (INIS)

    Reitz, G.

    2006-01-01

    The radiation exposure in space missions can be reduced by careful mission planning and appropriate measures, such as provision of a radiation shelter, but it cannot be eliminated. The reason for that is the high penetration capability of the radiation components owing to their high energies. Radiation is therefore an acknowledged primary concern for manned spaceflight and is a potentially limiting factor for long-term orbital and interplanetary missions. The radiation environment is a complex mixture of charged particles of solar and galactic origin and of the radiation belts, as well as of secondary particles produced in interactions of the galactic cosmic particles with the nuclei of atmosphere of the earth. The complexity even increases by placing a spacecraft into this environment owing to the interaction of the radiation components with the shielding material. Therefore it is a challenge to provide for appropriate measurements in this radiation field, coping with the limited resources on experiment power and mass. Solid-state dosemeters were already chosen for measurements in the first manned flights. Thermoluminescence dosemeters (TLDs) and plastic nuclear track detectors (PNTD) especially found a preferred application because they are light-weighted, need no power supply and they are tissue-equivalent. Most of the data available until 1996 were gathered by using these passive detectors; this especially holds for heavy ion particle spectra. The systems, supplemented by converter foils or fission detectors and bubble detectors, provide information on dose, particle flux-, energy- and linear energy transfer spectra of the ionising radiation and neutron fluxes and doses. From 1989, silicon detectors were used for dose and flux measurements and later on for particle spectrometry. Silicon detectors were demonstrated as a powerful tool for the description of space radiation environment. Optical simulated luminescence (OSL) detectors have now been introduced as a

  15. TL dosimetric properties BAM:EU

    International Nuclear Information System (INIS)

    Rao, Bellam N.; Murthy, K.V.R.; Subba Rao, B.; Saiprasad, A.S.

    2011-01-01

    In phosphor area today top priority is the replacement of the high performance but very expensive rare earth activated phosphors with cheaper materials. This essentially means replacing the rare earth ions with transition metal ions or post transition ions. Now a day's phosphors are used in various fields. After World War II, the advances in the optical spectroscopy of solids, especially those of transition metals ions help to evolve research on phosphor and solid state luminescence. In 1960 efficient rare earth activated phosphors were developed for use in color TV (Tb 3+ green, Eu 3+ red, and Dy 3+ yellow). In 1970 tricolor lamp was introduced blue emission from Ce 3+ + Tb 3+ pair was used in tricolor lamps. At present combination of halo phosphor and tri-band phosphor blend is used in many lamp as a compromise between performance, phosphor cost and the lamp making Cost. Thermo luminescence of 0.5 Gy X-ray irradiated BAM.Eu has been studied. The irradiated phosphor has been studied for its TL dosimetric properties one week after irradiation and after 100 weeks of storage. Interesting TL results are reported in the present paper. Heating rate used in the present experiment is 6.6 deg C/Sec. The following two figures are on TL recorded 100 weeks after irradiation and TL recorded after 235 weeks of storage. Before storage for 100 weeks the TL glow curve with a hump around 180 deg C followed by a peak at 273 deg C. After storage for 100 weeks the TL pattern changes entirely. i.e. the composite TL peak structure emerged as two well resolved peaks and with slightly higher TL peak temperatures at 215 deg C and 300 deg C. Normally after storage for 100 weeks the peak at 190 deg C reduces in its intensity or disappears in some cases, instead of that the peak appears at 215 deg C as well resolved peak and its intensity is almost comparable to that of 300 deg C peak. Since the TL phenomenon observed is interesting the two well resolved, isolated, high intensity peaks

  16. Interferometry of light particles with a CsI(Tl) multi-detector in the collision: 16O(93.6 MeV/A) + 197Au

    International Nuclear Information System (INIS)

    Goujdami, D.

    1987-01-01

    Back angle emissions of light particles have been studied by interferometry in the 16 0 + 197 Au reaction. The experiment was performed at GANIL at 93,6 MeV/A. To achieve the correlation functions in the average backward direction we built entirely a compact multi-detector of Csl scintillators which was set up at 115 degrees to the beam direction. This work describes the relevant tests of the detector, data taking and data processing. The p-p, α-α, d-d, α-d, α-t correlations that we studied exhibit a complete damping of two body resonant nuclear effects. The most surprising result concerns the p-p correlation which, by its new shape, could be the signature of a de-excitation process in two steps. The ordering time of the 2 proton cascade would be of the order of 1.5*10 -21 s. (author) [fr

  17. Solid State pH Sensor Based on Light Emitting Diodes (LED) As Detector Platform

    OpenAIRE

    Lau, King Tong; Shepherd, R.; Diamond, Danny; Diamond, Dermot

    2006-01-01

    A low-power, high sensitivity, very low-cost light emitting diode (LED)-based device developed for low-cost sensor networks was modified with bromocresol green membrane to work as a solid-state pH sensor. In this approach, a reverse-biased LED functioning as a photodiode is coupled with a second LED configured in conventional emission mode. A simple timer circuit measures how long (in microsecond) it takes for the photocurrent generated on the detector LED to discharge its capacitance from lo...

  18. Study on some characteristics of the polycarbonate Durolon used as a solid state nuclear track detector

    International Nuclear Information System (INIS)

    Sciani, V.; Pugliesi, R.; Moraes, M.A.P.V. de; Menezes, M.O. de; Miranda, A.

    1994-01-01

    Some characteristics of the polycarbonate Durolon as a solid state nuclear track detector were investigated. These were determined by means of irradiations performed at the IEA-R1 Nuclear Research Reactor of the IPEN-CNEN/SP. The results were compared with those obtained for Makrofol-E at the same conditions. Although Durolon is grooved, it presents a track registration efficiency and a light transmission of about 30% and 2,4 greater than the former, respectively. (author). 7 refs, 4 figs, 2 tabs

  19. Application of solid state nuclear track detectors in measurement of natural alpha- radioactivity in environment

    Energy Technology Data Exchange (ETDEWEB)

    Maged, A F; El-Behay, A Z; Borham, E [National Center for Radiation Research and Technology, Atomic Energy Authority, Cairo (Egypt)

    1997-12-31

    The use of solid state nuclear track detectors (SSNTDs) is one of the most convenient techniques to assess the average radiation levels of alpha activities in the environment. This technique has been used to assess radon gas and its daughters in buildings. Exposed SSNTD films are chemically etched in an alkali solution and alpha tracks are evaluated by using the image analyzer system. The detailed procedure for this study and the etched films for conversion of alpha track density to radon concentration in Bq m{sup -}3 are given and discussed in the text.1 fig., 3 tabs.

  20. In-core gamma dosimetry by solid state nuclear track detectors

    International Nuclear Information System (INIS)

    Khan, H.A.

    1980-02-01

    Results are reported of a study undertaken to develop Solid State Nuclear Track Detectors (SSNTD) for the measurement of gamma doses in the megarad region such as those existing in and around a nuclear reactor core. The changes brought about in the track etching parameters and in the ultraviolet and infrared transmittances, have been studied for possible use as gamma dose measuring indices. Effects of various parameters in the core such as neutron flux, beta particles, water, temperature, and gamma ray spectrum have been investigated and found to have only small influence on the proposed gamma dose measuring indices

  1. Sources of series resistance in the Harwell solid state alpha detector

    International Nuclear Information System (INIS)

    Rawlings, K.J.

    1985-12-01

    The metal-semiconductor contacts to the Harwell solid state alpha detector have been characterized and the effect of the contact geometry has been assessed. To a reasonable approximation the latter gives rise to an emitter series resistance with an expected range of 20 +- 8 ohms. The contacts behave like parallel RC networks which become noticeably frequency dependent above ca. 100 kHz. Up to this frequency the emitter contact is likely to add 6 +- 4 ohms to the series resistance and the contribution from the base contact varies inversely with the square of the diode's diameter, being 5 +- 3 ohms for a diode with a diameter of 30 mm. (author)

  2. Radon diffusion in polymer vessels using CR-39 solid state nuclear track detector

    Energy Technology Data Exchange (ETDEWEB)

    Carneiro, Andre Cavalcanti; Menezes, Maria Angela de B.C.; Rocha, Zildete; Pereira, Marcio Tadeu, E-mail: andreccarneiro@gmail.com, E-mail: menezes@cdtn.br, E-mail: zildete@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Santos, Talita de Oliveira; Lara, Evelise Gomes; Braga, Mario Roberto Martins S.S., E-mail: mariomartins@gmail.com, E-mail: evelise.lara@gmail.com, E-mail: talitaolsantos@yahoo.com.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil)

    2015-07-01

    At CDTN/CNEN, the method to determine {sup 226}Ra in several matrices by gamma spectrometry is already established; however, the method should be improved. This paper is about the first step of this improvement. Several polymer vessels were studied verifying the effect of radiolysis on the walls of the vessel. A test about the diffusion of {sup 222}Rn through the walls was carried out using the CR-39 solid state nuclear track detector. The results pointed out that the vessel made up by acrylic material is the best candidate to replace the vessel actually used. (author)

  3. Detection of fission fragments and alpha particles using the solid trace detector CR-39

    International Nuclear Information System (INIS)

    Santos, R.C.

    1988-01-01

    The technique of detecting charged particles using the solid track detector CR-39 is employed to establish some characteristics of fission fragments and alpha particles emitted from a Cf-252 source. Results are presented and discussed on the following aspects i) distribution of the track diameters; ii) variations on the track diameters to the chemical attack; iii) variations of the chemical attack velocity with respect to concentration and temperature. iv) activation energy of the developping process; v) induction time; vi) critical angle and efficiency on track developping. (A.C.A.S.) [pt

  4. Proton induced target fragmentation studies on solid state nuclear track detectors using Carbon radiators

    Science.gov (United States)

    Szabó, J.; Pálfalvi, J. K.; Strádi, A.; Bilski, P.; Swakoń, J.; Stolarczyk, L.

    2018-04-01

    One of the limiting factors of an astronaut's career is the dose received from space radiation. High energy protons, being the main components of the complex radiation field present on a spacecraft, give a significant contribution to the dose. To investigate the behavior of solid state nuclear track detectors (SSNTDs) if they are irradiated by such particles, SSNTD stacks containing carbon blocks were exposed to high energy proton beams (70, 100, 150 and 230 MeV) at the Proteus cyclotron, IFJ PAN -Krakow. The incident protons cannot be detected directly; however, tracks of secondary particles, recoils and fragments of the constituent atoms of the detector material and of the carbon radiator are formed. It was found that as the proton energy increases, the number of tracks induced in the PADC material by secondary particles decreases. From the measured geometrical parameters of the tracks the linear energy transfer (LET) spectrum and the dosimetric quantities were determined, applying appropriate calibration. In the LET spectra the LET range of the most important secondary particles could be identified and their abundance showed differences in the spectra if the detectors were short or long etched. The LET spectra obtained on the SSNTDs irradiated by protons were compared to LET spectra of detectors flown on the International Space Station (ISS): they were quite similar, resulting in a quality factor difference of only 5%. Thermoluminescent detectors (TLDs) were applied in each case to measure the dose from primary protons and other lower LET particles present in space. Comparing and analyzing the results of the TLD and SSNTD measurements, it was obtained that proton induced target fragments contributed to the total absorbed dose in 3.2% and to the dose equivalent in 14.2% in this particular space experiment.

  5. TL transgenic mouse strains

    International Nuclear Information System (INIS)

    Obata, Y.; Matsudaira, Y.; Hasegawa, H.; Tamaki, H.; Takahashi, T.; Morita, A.; Kasai, K.

    1993-01-01

    As a result of abnormal development of the thymus of these mice, TCR αβ lineage of the T cell differentiation is disturbed and cells belonging to the TCR γδ CD4 - CD8 - double negative (DN) lineage become preponderant. The γδ DN cells migrate into peripheral lymphoid organs and constitute nearly 50% of peripheral T cells. Immune function of the transgenic mice is severely impaired, indicating that the γδ cells are incapable of participating in these reactions. Molecular and serological analyses of T-cell lymphomas reveal that they belong to the γδ lineage. Tg.Tla a -3-1 mice should be useful in defining the role of TL in normal and abnormal T cell differentiation as well as in the development of T-cell lymphomas, and further they should facilitate studies on the differentiation and function of γδ T cells. We isolated T3 b -TL gene from B6 mice and constructed a chimeric gene in which T3 b -TL is driven by the promoter of H-2K b . With the chimeric gene, two transgenic mouse strains, Tg. Con.3-1 and -2 have been derived in C3H background. Both strains express TL antigen in various tissues including skin. The skin graft of transgenic mice on C3H and (B6 X C3H)F 1 mice were rejected. In the mice which rejected the grafts, CD8 + TCRαβ cytotoxic T cells (CTL) against TL antigens were recognized. The recognition of TL by CTL did not require the antigen presentation by H-2 molecules. The results indicated that TL antigen in the skin becomes a transplantation antigen and behaves like a typical allogeneic MHC class I antigen. The facts that (B6 X C3H)F 1 mice rejected the skin expressing T3 b -TL antigen and induced CTL that killed TL + lymphomas of B6 origin revealed that TL antigen encoded by T3 b -TL is recognized as non-self in B6 mice. Experiments are now extended to analyze immune responses to TL antigen expressed on autochthonous T cell lymphomas. (J.P.N.)

  6. Calibration of a solid state nuclear track detector for the measurements of volumic activity of Radon

    International Nuclear Information System (INIS)

    HAKAM, O.K.; LFERDE, M.; BERRADA, M.

    1994-01-01

    Time - integrated measurements of environmental radiation activity are commonly carried out using solid state nuclear track detectors ( SSNTD ). These detectors should be calibrated of volumic activity of radon. This paper reports the results of experiments conducted to calibrate cellulose nitrate films LR - 115 type II used for measurements of volumic activity of radon in indoor air in dwellings and enclosed work areas in Morocco. Calibration measurements were made in laboratory using a calibration chamber and a radon source. The calibration chamber is a cylindric box ( 2613,6 cm sup 3)which we have manufactured of aluminium. The radon source is a natural sample rich of aluminium (17,29 + 0 ,12) Bq/g. The films are placed in detector holder with membrane and exposed inside the calibration chamber to varying concentrations of radon. Following the exposure, the films were chemically etched in sodium hydroxide (2,5 N) at 60 C for 120 minutes. The number of registered alpha particle tracks were counted with an optical microscope. In the used etching conditions, the removed mean thickness is in the order of 6 micro m. Therefore, we have normalized the track density to this value . We obtained a calibration factor of 0, 58 tracks . cm sup -2/ K Bq . h . m sup -3 . 1 tab.; 1 fig.; 2 refs. (author)

  7. New thermal neutron solid-state electronic detector based on HgI2 crystals

    International Nuclear Information System (INIS)

    Melamud, M.; Burshtein, Z.

    1983-07-01

    We describe the development of a new solid-state electronic neutron detector, based on HgI 2 single crystals. Incident neutrons are absorbed in high neutron absorbing foils, such as cadmium or gadolinium, which are placed in front of a HgI 2 detector. Gamma rays, emitted as a result of the neutron absorbtion, are then absorbed in the HgI 2 , generating free charge carriers, which are collected by the electric field. The advantage of this system lies in it's manufacturing simplicity, low weight and small physical dimensions, compared to gas-filled conventional neutron detectors. The disadvantage is that the system does not discriminate between gamma rays and neutrons. A method to minimize this disadvantage is pointed out. It is as well possible to count neutrons by direct exposure of the HgI 2 to neutrons. The neutron-to-gamma transformation in that case takes place by the material nuclei themselves. This method, however, is impractical due to the interference of delayed radioactivity whose origin are 129 I nuclei. They are generated from 128 I by absorbing a neutron, and decay with a 25 min half lifetime involving gamma emissions. (author)

  8. Advances in CMOS solid-state photomultipliers for scintillation detector applications

    Energy Technology Data Exchange (ETDEWEB)

    Christian, James F.; Stapels, Christopher J.; Johnson, Erik B.; McClish, Mickel; Dokhale, Purushotthom; Shah, Kanai S.; Mukhopadhyay, Sharmistha; Chapman, Eric [Radiation Monitoring Devices, 44 Hunt Street, Watertownm, MA 02472 (United States); Augustine, Frank L., E-mail: JChristian@RMDInc.co [Augustine Engineering, 2115 Park Dale Ln, Encinitas, CA 92024 (United States)

    2010-12-11

    Solid-state photomultipliers (SSPMs) are a compact, lightweight, potentially low-cost alternative to a photomultiplier tube for a variety of scintillation detector applications, including digital-dosimeter and medical-imaging applications. Manufacturing SSPMs with a commercial CMOS process provides the ability for rapid prototyping, and facilitates production to reduce the cost. RMD designs CMOS SSPM devices that are fabricated by commercial foundries. This work describes the characterization and performance of these devices for scintillation detector applications. This work also describes the terms contributing to device noise in terms of the excess noise of the SSPM, the binomial statistics governing the number of pixels triggered by a scintillation event, and the background, or thermal, count rate. The fluctuations associated with these terms limit the resolution of the signal pulse amplitude. We explore the use of pixel-level signal conditioning, and characterize the performance of a prototype SSPM device that preserves the digital nature of the signal. In addition, we explore designs of position-sensitive SSPM detectors for medical imaging applications, and characterize their performance.

  9. Instruments and detectors on the base of scintillator crystals ZnSe(Te), CWO, CsI(Tl) for systems of security and customs inspection systems

    International Nuclear Information System (INIS)

    Ryzhikov, V.D.; Opolonin, A.D.; Pashko, P.V.; Svishch, V.M.; Volkov, V.G.; Lysetskaya, E.K.; Kozin, D.N.; Smith, C.

    2005-01-01

    Results of experimental studies of detector arrays scintillator-photodiode (S-PD) and scintillator-photoreceiving device (S-PRD) used for X-ray digital radiography have shown that there exist further possibilities to increase spatial resolution of this system up to 2-3 line pairs per mm. Theoretical analysis and experimental studies show that the two-energy detection method not only allows one to detect organics on the background of metal, but also substantially increases (by 3-5 times) the detection ability of the system as a whole, especially if parameters of the S-PD pair are optimized, in particular, when ZnSe(Te) is used in the low-energy circuit. A possibility to distinguish, in principle, between substances with insignificant differences in atomic number has been theoretically proven--by transition to multi-energy radiography. 3D-imaging has been realized using S-PD detector arrays. On base of theoretical and experimental search was installation of several types of inspection systems for control objects with square size 0.4x0.6-2.5x3.5 m

  10. SACALCCYL, Calculates the average solid angle subtended by a volume; SACALC2B, Calculates the average solid angle for source-detector geometries

    International Nuclear Information System (INIS)

    Whitcher, Ralph

    2007-01-01

    1 - Description of program or function: SACALC2B calculates the average solid angle subtended by a rectangular or circular detector window to a coaxial or non-coaxial rectangular, circular or point source, including where the source and detector planes are not parallel. SACALC C YL calculates the average solid angle subtended by a cylinder to a rectangular or circular source, plane or thick, at any location and orientation. This is needed, for example, in calculating the intrinsic gamma efficiency of a detector such as a GM tube. The program also calculates the number of hits on the cylinder side and on each end, and the average path length through the detector volume (assuming no scattering or absorption). Point sources can be modelled by using a circular source of zero radius. NEA-1688/03: Documentation has been updated (January 2006). 2 - Methods: The program uses a Monte Carlo method to calculate average solid angle for source-detector geometries that are difficult to analyse by analytical methods. The values of solid angle are calculated to accuracies of typically better than 0.1%. The calculated values from the Monte Carlo method agree closely with those produced by polygon approximation and numerical integration by Gardner and Verghese, and others. 3 - Restrictions on the complexity of the problem: The program models a circular or rectangular detector in planes that are not necessarily coaxial, nor parallel. Point sources can be modelled by using a circular source of zero radius. The sources are assumed to be uniformly distributed. NEA-1688/04: In SACALC C YL, to avoid rounding errors, differences less than 1 E-12 are assumed to be zero

  11. Development of neutron personnel monitoring system based on CR-39 solid state nuclear track detector

    International Nuclear Information System (INIS)

    Massand, O.P.; Kundu, H.K.; Marathe, P.K.; Supe, S.J.

    1990-01-01

    Personnel neutron monitoring aims at providing a method to evaluate the magnitude of the detrimental effects on the personnel exposed to neutrons. Neutron monitoring is done for a small though growing number of personnel working with neutrons in a wide range of situations. Over the years, many solid state nuclear track detectors (SSNTD) have been tried for neutron personnel monitoring. CR-39 SSNTD is a proton sensitive polymer and offers a lot of promise for neutron personnel monitoring due to its high sensitivity and lower energy threshold for neutron detection. This report presents the mechanism of track formation in this polymer, the development of this neutron personnel monitoring system in our laboratory, its various characteristics and its promise as a routine personnel neutron monitor. (author). 1 tab., 7 figs

  12. A high precision video-electronic measuring system for use with solid state track detectors

    International Nuclear Information System (INIS)

    Schott, J.U.; Schopper, E.; Staudte, R.

    1976-01-01

    A video-electronic image analyzing system Quantimet 720 has been modified to meet the requirements of the measurement of tracks of nuclear particles in solid state track detectors with resulting improvement of precision, speed, and the elimination of subjective influences. A microscope equipped with an automatic XY stage projects the image onto the cathode of a vidicon-amplifier. Within the TV-picture generated, characterized by the coordinate XY in the specimen, we determine coordinates xy of events by setting cross lines on the screen which correspond to a digital accuracy of 0.1 μm at the position of the object. Automatic movement in Z-direction can be performed by stepping motor and measured electronically, or continously by setting electric voltage on a piezostrictive support of the objective. (orig.) [de

  13. Ventilation rate in equilibrium factor measurements with solid state nuclear track detectors (SSNTD)

    International Nuclear Information System (INIS)

    Gil, L.R.; Leitao, R.M.S.; Marques, A.; Rivera, A.

    1994-08-01

    Ventilation rate values are calculated from track density measurements in solid state nuclear track detectors (SSNTD), both when ventilation is the main cause of radioactive disequilibrium in radon progeny and when it shares importance with other agents. The method consists in exposing a SSNTD of high intrinsic efficiency (CR-39) in filtered and unfiltered conditions and, in addition, covered with a thin Aluminium foil, to stop alpha particles from 218 Po and 222 Rn. No calibrations are required but, when necessary, independent measurements of the loss rates of radioactivity to aerosol and to walls have to perform. Ventilation rates depend upon geometry detection efficiencies for alpha particles, here obtained by Monte Carlo simulation, taking into account the space distribution of emission positions. This may lead to sizeable corrections in ventilation and equilibrium factor values. Since geometric detection efficiencies depend upon alpha-particle ranges in air, the influences of barometric variables are also discussed. (author). 7 refs

  14. Measurement of indoor radon levels in Erbil capital by using solid state nuclear track detectors

    International Nuclear Information System (INIS)

    Mansour, H.H.; Khdar, S. per; Abdulla, H.Y.; Muhamad, N.Q.; Othman, M.M.; Qader, S.

    2005-01-01

    Radon alpha activity concentration has been measured in 28 homes in the Erbil Capital-Iraqi Kurdistan region during the autumn season by using time-integrated passive radon dosimeters containing CR-39 solid state nuclear track detectors 'SSNTDs'. The radon activity concentrations in these homes range from (10.33-90.34) Bqm -3 with an average of 44+/-23Bqm -3 . The average absorption effective dose equivalent for a person living in homes for which the investigation were done was found to be 1.3+/-0.65mSvy -1 , obtained by using an equilibrium factor of 0.5 and an occupancy factor of 0.8. The average lung cancer cases per year per 10 6 person was found to be 23+/-12

  15. Detection of fission fragments using thick samples in contact with solid state nuclear track detectors

    International Nuclear Information System (INIS)

    Lima, D.A. de; Martins, J.B.; Tavares, O.A.P.

    1987-01-01

    Whenever use is made of thick samples in contact with solid state nuclear track detectors for determining fission yields, one of the fundamental problems is the evaluation of the effective number of target nuclei which contributes to the fraction of the number of fission events that will be recorded. The evaluation of the effective number of target nuclei which contributes to recorded events is based on the effective thickness of the sample. A method for evaluating effective thickness of thick samples for binary fission modes, is presented. A cross section equation which takes into account all the necessary corrections due to fragment attenuation effects by a thick target for calculation induced fission yields, was obtained. (Author) [pt

  16. An automatic analyzer of solid state nuclear track detectors using an optic RAM as image sensor

    International Nuclear Information System (INIS)

    Staderini, E.M.; Castellano, A.

    1986-01-01

    An optic RAM is a conventional digital random access read/write dynamic memory device featuring a quartz windowed package and memory cells regularly ordered on the chip. Such a device is used as an image sensor because each cell retains data stored in it for a time depending on the intensity of the light incident on the cell itself. The authors have developed a system which uses an optic RAM to acquire and digitize images from electrochemically etched CR39 solid state nuclear track detectors (SSNTD) in the track count rate up to 5000 cm -2 . On the digital image so obtained, a microprocessor, with appropriate software, performs image analysis, filtering, tracks counting and evaluation. (orig.)

  17. Mechanism of track formation by charged particles in inorganic and organic solid-state track detectors

    International Nuclear Information System (INIS)

    Doerschel, B.; Pretzsch, G.; Streubel, G.

    1979-01-01

    Knowledge of the individual phases of track formation mechanism is necessary in some applications of solid-state track detectors. The generation of latent tracks is described by energy transfer processes of the charged particles along their paths using several different models. Etchability of the latent tracks is discussed on the basis of some distinct criteria taking into account different fractions of energy release by the primary and secondary particles during track generation. If these etchability criteria for latent tracks are fulfilled, visual particle tracks can be produced by a chemical etching process. Etch pit formation depends on the etching conditions. The geometrical parameters of the etching pits are given on the basis of known etching rates. Evaluation of individual particle tracks or determination of track density yields results depending on both the properties of the particles and the etching conditions. Determination of particle energy and particle fluence is discussed as an example. (author)

  18. Dosimetric calibration of solid state detectors with low energy β sources

    International Nuclear Information System (INIS)

    Fidanzio, Andrea; Pia Toni, Maria; Capote, Roberto; Pena, Juan; Pasciuti, Katia; Bovi, Maurizio; Perrone, Franco; Azario, Luigi; Lazzeri, Mauro; Gaudino, Diego; Piermattei, Angelo

    2008-01-01

    A PTW Optidos plastic scintillation and a PTW natural diamond detectors were calibrated in terms of absorbed dose to water with β fields produced by 90 Sr + 90 Y and 85 Kr reference sources. Each source was characterized at the Italian National Metrological Institute - the Istituto Nazionale di Metrologia delle Radiazioni Ionizzanti of ENEA (ENEA-INMRI) - for two different series, 1 and 2, of ISO reference β-particle radiation fields. Beam flattening filters were used for the series 1 β fields to give uniform absorbed dose rates over a large area at a source-to-reference plane distance of 30 cm. The series 2 β fields were produced at source-to-reference plane distance of 10 cm, without the beam flattening filters, in order to obtain higher absorbed dose rates. The reference absorbed dose rate values were directly determined by the Italian national standard for β-particle dosimetry (a PTW extrapolation ionization chamber) for the series 1 β fields and by a calibrated transfer standard chamber, (a Capintec thin fixed-volume parallel plate ionization chamber) for the series 2 β fields. Finally the two solid state detectors were calibrated in terms of absorbed dose to water with the series 2 β field. The expanded uncertainties of the calibration coefficients obtained for the plastic scintillation dosimeter were 10% and 12% (2SD) for the 90 Sr + 90 Y and the 85 Kr sources, respectively. The expanded uncertainties obtained for the diamond dosimeter were 10% (2SD) and 16% (2SD) for the 90 Sr + 90 Y and the 85 Kr sources, respectively. The good results obtained with the 90 Sr + 90 Y and the 85 Kr β sources encourage to implement this procedure to calibrate this type of detectors at shorter distances and with other β sources of interest in brachytherapy, for example the 106 Ru source

  19. Proceedings of the twentieth national conference on solid state nuclear track detectors and their applications: abstracts

    International Nuclear Information System (INIS)

    2017-01-01

    Solid State Nuclear Track Detectors (SSNTDs) - A class of passive detectors, developed by R.L. Fleischer, P.B. Price and R.M. Walker in the early 1960s have found numerous applications in various fields of science and technology. SSNTDs have been recognized as very potential and effective tools in exploring various areas of research. The intrinsic features of SSNTDs like low cost , availability, versatility and their remarkable stability have contributed to applications in a wide range of fields opening up new vistas which were practically unthinkable and unbelievable about a decade or two ago. Apart from the direct applications of far reaching consequences in nuclear physics, other areas as diverse as bio-medical sciences, cosmic rays and space physics, environmental research, geochronology and geophysics, materials sciences, lunar science, meteorites and tektites; microanalysis, mine safety, nuclear technology, uranium prospecting and most recently nano/micro technology etc., have been greatly influenced by SSNTDs. They have a very important role to play in radiation measurement, micro technology and dosimetry and thus are potential enough in spreading awareness about the radiation environment and its impact on the general public and the academic peers. In order to disseminate the knowledge generated in this fast growing field, there is a need to bring material science and radiation community on a common platform and discuss various operational and radiation protection aspects. Papers relevant to INIS are indexed separately

  20. Radon-film-badges by solid radiators to complement track detector-based radon monitors

    International Nuclear Information System (INIS)

    Tommasino, L.; Tommasino, M.C.; Viola, P.

    2009-01-01

    Existing passive radon monitors, based on track detectors, present many shortcomings, such as a limited response sensitivity for one-week-indoor measurements and a limited response linearity for the assessment of large radon exposures indoors, in thermal spa, in caves, and in soil. Moreover, for in-soil measurements these monitors are too bulky and are often conducive to wrong results. For what concerns the radon-in-water measurements, they are just not suitable. A new generation of passive radon monitors is introduced in this paper, which are very similar to the compact badges used in neutron- and gamma-dosimetry and will be referred to as radon-film-badges. These film-badges are formed by thin-film radiators with suitable radon-sorption characteristics, facing track detectors. The key strategy adopted for these radiators is to exploit an equilibrium type of radon sorption in solids. Even though this new generation of passive monitors is at its infancy, it appears already clear that said monitors make it finally possible to overcome most of the shortcomings of existing passive radon monitors. These devices are uniquely simple and can be easily acquired by any existing radon service to complement their presently used passive radon monitors with little or no effort.

  1. Study of continuous DOI positioning for solid-state PET detectors

    International Nuclear Information System (INIS)

    Lee, Chae Hun

    2007-02-01

    PET is a nuclear imaging technique that measures the spatial and temporal distribution of compounds labeled with a positron emitting radionuclide introduced into a subject to be determined non-invasively. Spatial resolution degradation occurs at the edge of Field Of View (FOV) due to parallax error. To improve spatial resolution at the edge of FOV, Depth-Of-Interaction (DOI) PET has been investigated and there are several methods for DOI positioning. Among DOI positioning methods, sharing scintillation light output is the cost-effective and accurate method while solid-state photosensors such as Avalanche Photodiodes have been well developed. Avalanche photodiodes have internal gain by impact ionizations in high electric field. High gain and low noise are good characteristics for use in PET. In this thesis, DOI-PET detector using two APD with LSO scintillation crystal was designed and evaluated, and parameter to affect DOI positioning was investigated. Energy resolution of the designed detector was 12 % in 662 keV photopeak. Comparing photopeak channels of two APD output, DOI position was measured. DOI positioning error was ±2.5 mm. DOI resolution in current DOI-PET systems is still ∼ cm. Minimum 4 step positions can be obtained with 2 cm long LSO crystal in this result

  2. Flow electrochemical biosensors based on enzymatic porous reactor and tubular detector of silver solid amalgam

    Energy Technology Data Exchange (ETDEWEB)

    Josypčuk, Bohdan, E-mail: josypcuk@jh-inst.cas.cz [J. Heyrovský Institute of Physical Chemistry of AS CR, v.v.i., Department of Biophysical Chemistry, Dolejskova 3, Prague (Czech Republic); Barek, Jiří [Charles University in Prague, Faculty of Science, University Center of Excellence UNCE “Supramolecular Chemistry”, Department of Analytical Chemistry, UNESCO Laboratory of Environmental Electrochemistry, Albertov 6, CZ-128 43 Prague 2 (Czech Republic); Josypčuk, Oksana [J. Heyrovský Institute of Physical Chemistry of AS CR, v.v.i., Department of Biophysical Chemistry, Dolejskova 3, Prague (Czech Republic); Charles University in Prague, Faculty of Science, University Center of Excellence UNCE “Supramolecular Chemistry”, Department of Analytical Chemistry, UNESCO Laboratory of Environmental Electrochemistry, Albertov 6, CZ-128 43 Prague 2 (Czech Republic)

    2013-05-17

    Graphical abstract: -- Highlights: •Flow amperometric enzymatic biosensor was constructed. •The biosensor is based on a reactor of a novel material – porous silver solid amalgam. •Tubular amalgam detector was used for determination of decrease of O{sub 2} concentration. •Covalent bonds amalgam−thiol−enzyme contributed to the sensor long-term stability. •LOD of glucose was 0.01 mmol L{sup −1} with RSD = 1.3% (n = 11). -- Abstract: A flow amperometric enzymatic biosensor for the determination of glucose was constructed. The biosensor consists of a flow reactor based on porous silver solid amalgam (AgSA) and a flow tubular detector based on compact AgSA. The preparation of the sensor and the determination of glucose occurred in three steps. First, a self-assembled monolayer of 11-mercaptoundecanoic acid (MUA) was formed at the porous surface of the reactor. Second, enzyme glucose oxidase (GOx) was covalently immobilized at MUA-layer using N-ethyl-N′-(3-dimethylaminopropyl) carboimide and N-hydroxysuccinimide chemistry. Finally, a decrease of oxygen concentration (directly proportional to the concentration of glucose) during enzymatic reaction was amperometrically measured on the tubular detector under flow injection conditions. The following parameters of glucose determination were optimized with respect to amperometric response: composition of the mobile phase, its concentration, the potential of detection and the flow rate. The calibration curve of glucose was linear in the concentration range of 0.02–0.80 mmol L{sup −1} with detection limit of 0.01 mmol L{sup −1}. The content of glucose in the sample of honey was determined as 35.5 ± 1.0 mass % (number of the repeated measurements n = 7; standard deviation SD = 1.2%; relative standard deviation RSD = 3.2%) which corresponds well with the declared values. The tested biosensor proved good long-term stability (77% of the current response of glucose was retained after 35 days)

  3. Amperometric detector for gas chromatography based on a silica sol-gel solid electrolyte.

    Science.gov (United States)

    Steinecker, William H; Miecznikowski, Krzysztof; Kulesza, Pawel J; Sandlin, Zechariah D; Cox, James A

    2017-11-01

    An electrochemical cell comprising a silica sol-gel solid electrolyte, a working electrode that protrudes into a gas phase, and reference and counter electrodes that contact the solid electrolyte comprises an amperometric detector for gas chromatography. Under potentiostatic conditions, a current related to the concentration of an analyte in the gas phase is produced by its oxidation at the three-phase boundary among the sol-gel, working electrode, and the gas phase. The sol-gel is processed to contain an electrolyte that also serves as a humidistat to maintain a constant water activity even in the presence the gas chromatographic mobile phase. Response was demonstrated toward a diverse set of analytes, namely hydrogen, 1,2-ethandithiol, phenol, p-cresol, and thioanisole. Using flow injection amperometry of hydrogen with He as the carrier gas, 90% of the steady-state current was achieved in < 1s at a flow rate of 20mLmin -1 . A separation of 1,2-ethandithiol, phenol, p-cresol, and thioanisole at a 2.2mLmin -1 flow rate was achieved with respective detection limits (k = 3 criterion) of 4, 1, 3, and 70 ppmv when the working electrode potential was 800mV. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Physical changes associated with gamma doses of PM-555 solid-state nuclear track detector

    International Nuclear Information System (INIS)

    Nouh, S.A.

    2004-01-01

    The effect of gamma irradiation on the electrical, molecular and structural properties of copolymers of methacrylic esters and olefins, PM-555 solid-state nuclear track detector was investigated. DC conductivity measurements were studied in the temperature range 293-417 K using solid-state samples of the PM-555 polymer. These samples were irradiated with gamma doses in the range 5-63 kGy. Furthermore, the activation energy was measured, at various temperatures, as a function of the gamma dose. It was found that many changes in electrical resistance of PM-555 polymer could be produced by gamma irradiation via the degradation mechanism. Also, the gamma dose gives an advantage for the increasing correlation between the DC conductivity and the number and mobility of the charge carriers created by the ionizing effect of gamma radiation. Moreover, solutions of different loadings (0.2%, 0.4%, 0.6% and 0.8%) were prepared from the irradiated and non irradiated sheets using pure chloroform as a solvent. The effect of both temperature and gamma dose on the intrinsic viscosity of the liquid samples, as a measure of the mean molecular mass of the PM-555 polymer, were studied. In addition, structural and optical property studies using X-ray diffraction and refractive index measurements were performed on all irradiated and non irradiated PM-555 samples. The results indicate that both the degree of ordering or disordering and the anisotropic character of the PM-555 polymer are dependent on the gamma dose

  5. Comparison of sodium iodide and solid-state detectors for the measurement of lung-stored uranium

    International Nuclear Information System (INIS)

    King, A.; Scott, L.M.; Disney, J.L.

    1978-01-01

    A series of measurement of uranium sources were made, using a solid state detector consisting of 4 high-purity germanium detectors, and compared with measurements made with a single NaI detector. The comparative efficiencies at various energies are shown. As energy increases the differences in efficiencies increase in favour of NaI. A estimate of detection sensitivity gave the limit of error on the net count of a subject with one maximum permissible lung burden as 27 +- 7.2 counts/min for NaI and 3.73 +- 1.04 counts/min for the solid state detector. On a microgram basis the respective limits of error are +- 66 and +- 67 μg. It is concluded that solid state detectors can give 17 times better resolution compared with NaI while maintaining the same detection sensitivity. Sensitivity is related to the scatter of higher energy gammas into a fairly wide energy range. This 17-fold improvement in resolution results in a narrower energy range in which the scattered radiation can fall. Thus gamma analysis with such a system would be less subject to background errors. (author)

  6. Dielectric and baric characteristics of TlS single crystal

    Energy Technology Data Exchange (ETDEWEB)

    Mustafaeva, S.N., E-mail: solmust@gmail.com [Institute of Physics, ANAS, G. Javid prosp. 33, Az 1143 Baku (Azerbaijan); Asadov, M.M. [Institute of Chemical Problems, ANAS, G. Javid prosp. 29, Az 1143 Baku (Azerbaijan); Ismailov, A.A. [Institute of Physics, ANAS, G. Javid prosp. 33, Az 1143 Baku (Azerbaijan)

    2014-11-15

    The investigation of the frequency dependences of the dielectric coefficients and ac-conductivity of the TlS single crystals made it possible to elucidate the nature of dielectric loss and the charge transfer mechanism. Moreover, we evaluated the density and energy spread of localized states near the Fermi level, the average hopping time and the average hopping length. It was shown that the dc-conductivity of the TlS single crystals can be controlled by varying the hydrostatic pressure. This has opened up possibilities for using TlS single crystals as active elements of pressure detectors.

  7. Alpha-particle dosimetry using solid state nuclear track detectors. Application to 222Rn and its daughters

    International Nuclear Information System (INIS)

    Barillon, R.; Chambaudet, A.

    2000-01-01

    A methodology for the determination of the detection efficiency of a solid state nuclear track detector for radon and its short-lived daughters was presented. First, particular attention is paid to the α-particles having energies and angles of incidence that lead to observable tracks after an adapted chemical etching. The results are then incorporated in a mathematical model to determine the theoretical radon detection efficiency of a polymeric detector placed in a cylindrical cell. When applied to LR115 and CR39 detectors, the model reveals the influence of the position of the radon daughters inside the cell. Radon daughters tend to link up with natural atmospheric aerosols and then settle on the cell's inside wall. This model allows to determine, among other things, the cell size for which the detector response is independent of the fraction daughters plated out. (author)

  8. Kinetic parameters and TL mechanism in cadmium tetra borate phosphor

    International Nuclear Information System (INIS)

    Annalakshmi, O.; Jose, M.T.; Sridevi, J.; Venkatraman, B.; Amarendra, G.; Mandal, A.B.

    2014-01-01

    Polycrystalline powder samples of cadmium tetra borate were synthesized by a simple solid state sintering technique and gamma irradiated sample showed a simple Thermoluminescence (TL) glow peak around 460 K. The TL kinetic parameters of gamma irradiated phosphor were determined by initial rise (IR), isothermal decay (ID), peak shape (PS), variable heating rate (VHR) and glow curve de-convolution method. The kinetic parameters such as activation energy (E), frequency factor (s) and order of kinetics (b) were calculated by IR, ID, PS and VHR methods are in the order of ∼1.05 eV, 10 9 –10 12 s −1 and 1.58, respectively. From the results of TL and PL emission studies carried out on the phosphor revealed that the defect centers related to TL is different from that for PL. EPR measurements were carried out to identify the defect centers formed in cadmium tetra borate phosphor on gamma irradiation. Based on EPR studies the mechanism for TL process in cadmium tetra borate is proposed in this paper -- Highlights: • Polycrystalline powder samples of undoped cadmium tetra borate synthesized. • Cadmium tetra borate phosphor exhibits a dosimetric peak at 458 K. • Kinetic parameters of the trap responsible for TL evaluated. • TL mechanism is proposed from TL to EPR correlation studies

  9. Kinetic parameters and TL mechanism in cadmium tetra borate phosphor

    Energy Technology Data Exchange (ETDEWEB)

    Annalakshmi, O. [Radiological Safety Division, Materials Physics Division, Indira Gandhi Centre for Atomic Research, Kalpakkam-603102 (India); Jose, M.T., E-mail: mtj@igcar.gov.in [Radiological Safety Division, Materials Physics Division, Indira Gandhi Centre for Atomic Research, Kalpakkam-603102 (India); Sridevi, J. [Central Leather Research Institute, Council of Scientific and Industrial Research, Chennai 600 020, Tamilnadhu (India); Venkatraman, B. [Radiological Safety Division, Materials Physics Division, Indira Gandhi Centre for Atomic Research, Kalpakkam-603102 (India); Amarendra, G. [Materials Physics Division, Indira Gandhi Centre for Atomic Research, Kalpakkam-603102 (India); Mandal, A.B. [Central Leather Research Institute, Council of Scientific and Industrial Research, Chennai 600 020, Tamilnadhu (India)

    2014-03-15

    Polycrystalline powder samples of cadmium tetra borate were synthesized by a simple solid state sintering technique and gamma irradiated sample showed a simple Thermoluminescence (TL) glow peak around 460 K. The TL kinetic parameters of gamma irradiated phosphor were determined by initial rise (IR), isothermal decay (ID), peak shape (PS), variable heating rate (VHR) and glow curve de-convolution method. The kinetic parameters such as activation energy (E), frequency factor (s) and order of kinetics (b) were calculated by IR, ID, PS and VHR methods are in the order of ∼1.05 eV, 10{sup 9}–10{sup 12} s{sup −1} and 1.58, respectively. From the results of TL and PL emission studies carried out on the phosphor revealed that the defect centers related to TL is different from that for PL. EPR measurements were carried out to identify the defect centers formed in cadmium tetra borate phosphor on gamma irradiation. Based on EPR studies the mechanism for TL process in cadmium tetra borate is proposed in this paper -- Highlights: • Polycrystalline powder samples of undoped cadmium tetra borate synthesized. • Cadmium tetra borate phosphor exhibits a dosimetric peak at 458 K. • Kinetic parameters of the trap responsible for TL evaluated. • TL mechanism is proposed from TL to EPR correlation studies.

  10. Determination of boron in aqueous solutions by solid state nuclear track detectors technique, using a filtered neutron beam

    International Nuclear Information System (INIS)

    Moraes, M.A.P.V. de; Pugliesi, R.; Khouri, M.T.F.C.

    1985-11-01

    The solid state nuclear track detectors technique has been used for determination of boron in aqueous solutions, using a filtered neutron beam. The particles tracks from the 10 B(n,α)Li 7 reaction were registered in the CR-39 film, chemically etched in a (30%) KOH solution 70 0 C during 90 minutes. The obtained results showed the usefulness of this technique for boron determination in the ppm range. The inferior detectable limit was 9 ppm. The combined track registration efficiency factor K has been evaluated in the solutions, for the CR-39 detector and its values is K= (4,60 - + 0,06). 10 -4 cm. (Author) [pt

  11. Improved processes in therapy dosimetry with solid LiF thermoluminescent detectors

    International Nuclear Information System (INIS)

    Toivonen, M.

    1991-08-01

    The thesis presents criteria for thermoluminescence dosimetry systems suitable for precision measurements and, moreover, a detailed examination of the sources of systematic and random error. Instructions are given for annealing processes, calibration procedures, quality control, and operational rules, which are necessary in modem TLD. The performances of some principally different systems are compared. The old LiF-powder-based TLD system, with an overall uncertainty of measurement of about 1.6 percent for ten repeated readouts and for irradiations under calibration conditions with Co-60, is still the best but a comparable, although slightly lower, accuracy of about 1.7 percent can be reached more conveniently with solid LiF detectors. In measurements where absolute system calibration is not of interest (i.e., in depth-dose curve measurements, etc.), the advantages of the simple powder-based system are even more concrete. An integrated TLD process is presented for progressive utilization of automation in precision measurements. The sources of random error and unknown systematic error in current readout instruments are examined. Mechanical tolerances in critical parts of the readout instruments are thought to be the reason why the method of heating with hot gas has not been superior with respect to the precision of measurements, in spite of the excellent repeatability of the glow curve shape observed for successive readouts

  12. Estimation of radon progeny equilibrium factors and their uncertainty bounds using solid state nuclear track detectors

    International Nuclear Information System (INIS)

    Eappen, K.P.; Mayya, Y.S.; Patnaik, R.L.; Kushwaha, H.S.

    2006-01-01

    For the assessment of inhalation doses due to radon and its progeny to uranium mine workers, it is necessary to have information on the time integrated gas concentrations and equilibrium factors. Passive single cup dosimeters using solid state nuclear track detectors (SSNTD) are best suited for this purpose. These generally contain two SSNTDs, one placed inside the cup to measure only the radon gas concentration and other outside the cup for recording tracks due to both radon gas and the progeny species. However, since one obtains only two numbers by this method whereas information on four quantities is required for an unambiguous estimation of dose, there is a need for developing an optimal methodology for extracting information on the equilibrium factors. Several techniques proposed earlier have essentially been based on deterministic approaches, which do not fully take into account all the possible uncertainties in the environmental parameters. Keeping this in view, a simple 'mean of bounds' methodology is proposed to extract equilibrium factors based on their absolute bounds and the associated uncertainties as obtained from general arguments of radon progeny disequilibrium. This may be considered as reasonable estimates of the equilibrium factors in the absence of a knowledge of fluctuation in the environmental variables. The results are compared with those from direct measurements both in the laboratory and in real field situations. In view of the good agreement found between these, it is proposed that the simple mean of bounds estimate may be useful for practical applications in inhalation dosimetry of mine workers

  13. Solid State pH Sensor Based on Light Emitting Diodes (LED As Detector Platform

    Directory of Open Access Journals (Sweden)

    Dermot Diamond

    2006-08-01

    Full Text Available A low-power, high sensitivity, very low-cost light emitting diode (LED-baseddevice developed for low-cost sensor networks was modified with bromocresol greenmembrane to work as a solid-state pH sensor. In this approach, a reverse-biased LEDfunctioning as a photodiode is coupled with a second LED configured in conventionalemission mode. A simple timer circuit measures how long (in microsecond it takes for thephotocurrent generated on the detector LED to discharge its capacitance from logic 1 ( 5 Vto logic 0 ( 1.7 V. The entire instrument provides an inherently digital output of lightintensity measurements for a few cents. A light dependent resistor (LDR modified withsimilar sensor membrane was also used as a comparison method. Both the LED sensor andthe LDR sensor responded to various pH buffer solutions in a similar way to obtainsigmoidal curves expected of the dye. The pKa value obtained for the sensors was found toagree with the literature value.

  14. Solid State pH Sensor Based on Light Emitting Diodes (LED) As Detector Platform

    Science.gov (United States)

    Lau, King Tong; Shepherd, R.; Diamond, Danny; Diamond, Dermot

    2006-01-01

    A low-power, high sensitivity, very low-cost light emitting diode (LED)-based device developed for low-cost sensor networks was modified with bromocresol green membrane to work as a solid-state pH sensor. In this approach, a reverse-biased LED functioning as a photodiode is coupled with a second LED configured in conventional emission mode. A simple timer circuit measures how long (in microsecond) it takes for the photocurrent generated on the detector LED to discharge its capacitance from logic 1 (+5 V) to logic 0 (+1.7 V). The entire instrument provides an inherently digital output of light intensity measurements for a few cents. A light dependent resistor (LDR) modified with similar sensor membrane was also used as a comparison method. Both the LED sensor and the LDR sensor responded to various pH buffer solutions in a similar way to obtain sigmoidal curves expected of the dye. The pKa value obtained for the sensors was found to agree with the literature value.

  15. Development of an area monitor for neutrons using solid state nuclear track detector

    International Nuclear Information System (INIS)

    Zahn, G.S.

    1994-01-01

    An area monitor for neutrons composed of the solid state nuclear track detector (SSNTD) Makrofol DE, together with a (n,α) converter, in the center of a 25 cm diameter polyethylene sphere, is developed. The optimal electrochemical etching conditions for the detection of thermal neutrons by the Makrofol DE using the BN converter are studied, leading to the choice of 55 min, at 30 0 C, under a 44,2 kV.cm -1 electric field with oscillation frequency of 2,0 khz. The response of this system to thermal neutrons, in the optimal conditions, is of 2,76(10)x 10 -3 tr/n. Changing from the BN converter to a 2,73(3)g compressed boric acid tablet this value lowers to 3,88(17)x 10 -4 tr/n. The performance of the whole monitor in the detection of fast neutrons is examined using the BN converter and neutrons from a 241 Am Be source, with a response of 4,4(2)x 10 3 tr.mSv -1 .cm -2 and operational limits between 7(3)μSv and 5,6(2)mSv. The result of the monitoring of the control room of the IPEN Cyclotron accelerator are also presented as a final test for the viability of the practical use of the monitor. (author). 34 refs, 15 figs, 6 tabs, 1 app

  16. The physics of solid-state neutron detector materials and geometries.

    Science.gov (United States)

    Caruso, A N

    2010-11-10

    Detection of neutrons, at high total efficiency, with greater resolution in kinetic energy, time and/or real-space position, is fundamental to the advance of subfields within nuclear medicine, high-energy physics, non-proliferation of special nuclear materials, astrophysics, structural biology and chemistry, magnetism and nuclear energy. Clever indirect-conversion geometries, interaction/transport calculations and modern processing methods for silicon and gallium arsenide allow for the realization of moderate- to high-efficiency neutron detectors as a result of low defect concentrations, tuned reaction product ranges, enhanced effective omnidirectional cross sections and reduced electron-hole pair recombination from more physically abrupt and electronically engineered interfaces. Conversely, semiconductors with high neutron cross sections and unique transduction mechanisms capable of achieving very high total efficiency are gaining greater recognition despite the relative immaturity of their growth, lithographic processing and electronic structure understanding. This review focuses on advances and challenges in charged-particle-based device geometries, materials and associated mechanisms for direct and indirect transduction of thermal to fast neutrons within the context of application. Calorimetry- and radioluminescence-based intermediate processes in the solid state are not included.

  17. First results of the deployment of a SoLid detector module at the SCK•CEN BR2 reactor

    Science.gov (United States)

    Ryder, N.

    The SoLid experiment aims to resolve the reactor neutrino anomaly by searching for electron-to-sterile anti-neutrino oscillations. The search will be performed between 5.5 and 10 m from the highly enriched uranium core of the BR2 reactor at SCK-CEN. The experiment utilises a novel approach to anti-neutrino detection based on a highly segmented, composite scintillator detector design. High experimental sensitivity can be achieved using a combination of high neutron-gamma discrimination using 6 LiF:ZnS(Ag) and precise localisation of the inverse beta decay products. This compact detector system requires limited passive shielding as it relies on spacial topology to determine the different classes of backgrounds. The first full scale, 288 kg, detector module was deployed at the BR2 reactor in November 2014. A phased three tonne experimental deployment will begin in the second half of 2016, allowing a precise search for oscillations that will resolve the reactor anomaly using a three tonne detector running for three years. In this talk the novel detector design is explained and initial detector performance results from the module level deployment are presented along with an estimation of the physics reach of the next phase.

  18. Realization of an automatic set up to measure electrical characteristic of solid state detectors

    International Nuclear Information System (INIS)

    Manfredotti, C.; Crosetto, D.; Gabutti, A.; Gervino, G.; Varesio, R.

    1986-01-01

    An automatic set-up is described to study electrical properties of silicon detectors for nuclear research. Particularly, I-V characteristics from silicon junction prototype detectors and amorphous samples to test the data acquisition system, are presented. This set-up joins a low cost to good versatility that makes it very useful in wide application ranges in silicon detector electrical characterization

  19. Method for calibration of the NaI(Tl) 3''x 3'' detector for in vivo measurements in patients undergoing radioiodine therapy and occupationally exposed individuals to 131I

    International Nuclear Information System (INIS)

    Xavier, A.C.S.; Oliveira, M.L.; Lima, F.F.; Lima, F.R.A.; Lacerda, I.V.B.; Universidade Federal de Pernambuco

    2012-01-01

    According to studies by the Instituto Nacional do Cancer (INCA), in recent years the incidence of thyroid cancer is the fastest growing in relation to other types. For the treatment is required the exact amount of 131 I isotope for each patient resulting on manipulation of this isotope in nuclear medicine services by individuals who are considered occupationally exposed (OEI). This work aims to establish the methodology for calibration of the detection system used to determine the therapeutic activity of 131 I, required to release the desired absorbed dose in the thyroid gland, as well as in monitoring OEI that manipulate this radionuclide in nuclear medicine services. This is one of the early stages of implementation of Laboratorio de Dosimetria Interna at the Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE). The detector system consists of a NaI(Tl) 3'' x 3'' associated with electronic devices and Genie 2000 software. Sources of 60 Co, 137 Cs and 133 Ba were utilized for calibration. Firstly, measurements were carried out in non-exposed individuals for obtaining the Minimum Detectable Activity (MDA) and then Minimum Detectable Incorporation (MDI) and the Minimum Effective Dose Detectable (MEDD) were determined through biokinetic models provided by the ICRP 67 and edited by the AIDE software version 6 to workers and patients. The values for the MEDD were 3.57 x 10 -2 mSv, 5.56 x 10 -2 mSv and 10.7 x 10 -2 mSv to 1, 7 and 14 days, respectively, after 131 I incorporation by workers. As for patients, MEDD were 3.44 x 10 -2 mSv, 5.63 x 10 -2 mSv and 10.9 x 10 -2 mSv for the same periods of time. It is applicable to the assessment of dose OEI, since it presents less than the recommended minimum of 1 mSv. The technique also has adequate sensitivity for evaluation of activity present in the thyroid of patients with thyroid dysfunction. (author)

  20. The role of a chemical bond in thermal expansion of TlIn1-xYbxSe2 solid solutions

    International Nuclear Information System (INIS)

    Zarbaliev, M.M.; Sardarova, N.S.; Mamedov, E.G.; Nagiyev, A.B.

    2008-01-01

    Report focuses on the study of the role of the chemical bond in the thermal expansion of solid solutions TLIn 1 -x Yb x Se 2 (0

  1. A new method for determining the uranium and thorium distribution in volcanic rock samples using solid state nuclear track detectors

    International Nuclear Information System (INIS)

    Misdaq, M.A.; Bakhchi, A.; Ktata, A.; Koutit, A.; Lamine, J.; Ait nouh, F.; Oufni, L.

    2000-01-01

    A method based on using solid state nuclear track detectors (SSNTD) CR- 39 and LR-115 type II and calculating the probabilities for the alpha particles emitted by the uranium and thorium series to reach and be registered on these films was utilized for uranium and thorium contents determination in various geological samples. The distribution of uranium and thorium in different volcanic rocks has been investigated using the track fission method. In this work, the uranium and thorium contents have been determined in different volcanic rock samples by using CR-39 and LR-115 type II solid state nuclear track detectors (SSNTD). The mean critical angles of etching of the solid state nuclear track detectors utilized have been calculated. A petrographical study of the volcanic rock thin layers studied has been conducted. The uranium and thorium distribution inside different rock thin layers has been studied. The mechanism of inclusion of the uranium and thorium nuclei inside the volcanic rock samples studied has been investigated. (author)

  2. SOLID2: an antibody array-based life-detector instrument in a Mars Drilling Simulation Experiment (MARTE).

    Science.gov (United States)

    Parro, Víctor; Fernández-Calvo, Patricia; Rodríguez Manfredi, José A; Moreno-Paz, Mercedes; Rivas, Luis A; García-Villadangos, Miriam; Bonaccorsi, Rosalba; González-Pastor, José Eduardo; Prieto-Ballesteros, Olga; Schuerger, Andrew C; Davidson, Mark; Gómez-Elvira, Javier; Stoker, Carol R

    2008-10-01

    A field prototype of an antibody array-based life-detector instrument, Signs Of LIfe Detector (SOLID2), has been tested in a Mars drilling mission simulation called MARTE (Mars Astrobiology Research and Technology Experiment). As one of the analytical instruments on the MARTE robotic drilling rig, SOLID2 performed automatic sample processing and analysis of ground core samples (0.5 g) with protein microarrays that contained 157 different antibodies. Core samples from different depths (down to 5.5 m) were analyzed, and positive reactions were obtained in antibodies raised against the Gram-negative bacterium Leptospirillum ferrooxidans, a species of the genus Acidithiobacillus (both common microorganisms in the Río Tinto area), and extracts from biofilms and other natural samples from the Río Tinto area. These positive reactions were absent when the samples were previously subjected to a high-temperature treatment, which indicates the biological origin and structural dependency of the antibody-antigen reactions. We conclude that an antibody array-based life-detector instrument like SOLID2 can detect complex biological material, and it should be considered as a potential analytical instrument for future planetary missions that search for life.

  3. Method for calibration of the NaI(Tl) 3''x 3'' detector for in vivo measurements in patients undergoing radioiodine therapy and occupationally exposed individuals to {sup 131}I; Metodologia para calibracao do detector de NaI(Tl) 3''x 3''para medicoes in vivo em pacientes submetidos a radioiodoterapia e individuos ocupacionalmente expostos ao {sup 131}I

    Energy Technology Data Exchange (ETDEWEB)

    Xavier, A.C.S.; Oliveira, M.L.; Lima, F.F.; Lima, F.R.A. [Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil); Lacerda, I.V.B., E-mail: line_c7@hotmail.com [Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil); Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Programa de Pos-Graduacao em Tecnologias Energeticas e Nucleares

    2012-07-01

    According to studies by the Instituto Nacional do Cancer (INCA), in recent years the incidence of thyroid cancer is the fastest growing in relation to other types. For the treatment is required the exact amount of {sup 131}I isotope for each patient resulting on manipulation of this isotope in nuclear medicine services by individuals who are considered occupationally exposed (OEI). This work aims to establish the methodology for calibration of the detection system used to determine the therapeutic activity of {sup 131}I, required to release the desired absorbed dose in the thyroid gland, as well as in monitoring OEI that manipulate this radionuclide in nuclear medicine services. This is one of the early stages of implementation of Laboratorio de Dosimetria Interna at the Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE). The detector system consists of a NaI(Tl) 3'' x 3'' associated with electronic devices and Genie 2000 software. Sources of {sup 60}Co, {sup 137}Cs and {sup 133}Ba were utilized for calibration. Firstly, measurements were carried out in non-exposed individuals for obtaining the Minimum Detectable Activity (MDA) and then Minimum Detectable Incorporation (MDI) and the Minimum Effective Dose Detectable (MEDD) were determined through biokinetic models provided by the ICRP 67 and edited by the AIDE software version 6 to workers and patients. The values for the MEDD were 3.57 x 10{sup -2} mSv, 5.56 x 10{sup -2} mSv and 10.7 x 10{sup -2} mSv to 1, 7 and 14 days, respectively, after {sup 131}I incorporation by workers. As for patients, MEDD were 3.44 x 10{sup -2} mSv, 5.63 x 10{sup -2} mSv and 10.9 x 10{sup -2} mSv for the same periods of time. It is applicable to the assessment of dose OEI, since it presents less than the recommended minimum of 1 mSv. The technique also has adequate sensitivity for evaluation of activity present in the thyroid of patients with thyroid dysfunction. (author)

  4. The design and imaging characteristics of dynamic, solid-state, flat-panel x-ray image detectors for digital fluoroscopy and fluorography

    International Nuclear Information System (INIS)

    Cowen, A.R.; Davies, A.G.; Sivananthan, M.U.

    2008-01-01

    Dynamic, flat-panel, solid-state, x-ray image detectors for use in digital fluoroscopy and fluorography emerged at the turn of the millennium. This new generation of dynamic detectors utilize a thin layer of x-ray absorptive material superimposed upon an electronic active matrix array fabricated in a film of hydrogenated amorphous silicon (a-Si:H). Dynamic solid-state detectors come in two basic designs, the indirect-conversion (x-ray scintillator based) and the direct-conversion (x-ray photoconductor based). This review explains the underlying principles and enabling technologies associated with these detector designs, and evaluates their physical imaging characteristics, comparing their performance against the long established x-ray image intensifier television (TV) system. Solid-state detectors afford a number of physical imaging benefits compared with the latter. These include zero geometrical distortion and vignetting, immunity from blooming at exposure highlights and negligible contrast loss (due to internal scatter). They also exhibit a wider dynamic range and maintain higher spatial resolution when imaging over larger fields of view. The detective quantum efficiency of indirect-conversion, dynamic, solid-state detectors is superior to that of both x-ray image intensifier TV systems and direct-conversion detectors. Dynamic solid-state detectors are playing a burgeoning role in fluoroscopy-guided diagnosis and intervention, leading to the displacement of x-ray image intensifier TV-based systems. Future trends in dynamic, solid-state, digital fluoroscopy detectors are also briefly considered. These include the growth in associated three-dimensional (3D) visualization techniques and potential improvements in dynamic detector design

  5. SoLid: Search for Oscillations with Lithium-6 Detector at the SCK-CEN BR2 reactor

    Science.gov (United States)

    Ban, G.; Beaumont, W.; Buhour, J. M.; Coupé, B.; Cucoanes, A. S.; D'Hondt, J.; Durand, D.; Fallot, M.; Fresneau, S.; Giot, L.; Guillon, B.; Guilloux, G.; Janssen, X.; Kalcheva, S.; Koonen, E.; Labare, M.; Moortgat, C.; Pronost, G.; Raes, L.; Ryckbosch, D.; Ryder, N.; Shitov, Y.; Vacheret, A.; Van Mulders, P.; Van Remortel, N.; Weber, A.; Yermia, F.

    2016-04-01

    Sterile neutrinos have been considered as a possible explanation for the recent reactor and Gallium anomalies arising from reanalysis of reactor flux and calibration data of previous neutrino experiments. A way to test this hypothesis is to look for distortions of the anti-neutrino energy caused by oscillation from active to sterile neutrino at close stand-off (˜ 6- 8m) of a compact reactor core. Due to the low rate of anti-neutrino interactions the main challenge in such measurement is to control the high level of gamma rays and neutron background. The SoLid experiment is a proposal to search for active-to-sterile anti-neutrino oscillation at very short baseline of the SCK•CEN BR2 research reactor. This experiment uses a novel approach to detect anti-neutrino with a highly segmented detector based on Lithium-6. With the combination of high granularity, high neutron-gamma discrimination using 6LiF:ZnS(Ag) and precise localization of the Inverse Beta Decay products, a better experimental sensitivity can be achieved compared to other state-of-the-art technology. This compact system requires minimum passive shielding allowing for very close stand off to the reactor. The experimental set up of the SoLid experiment and the BR2 reactor will be presented. The new principle of neutrino detection and the detector design with expected performance will be described. The expected sensitivity to new oscillations of the SoLid detector as well as the first measurements made with the 8 kg prototype detector deployed at the BR2 reactor in 2013-2014 will be reported.

  6. Performance of novel materials for radiation detection: Tl3AsSe3, TlGaSe2, and Tl4HgI6

    International Nuclear Information System (INIS)

    Kahler, D.; Singh, N.B.; Knuteson, D.J.; Wagner, B.; Berghmans, A.; McLaughlin, S.; King, M.; Schwartz, K.; Suhre, D.; Gotlieb, M.

    2011-01-01

    In this paper we report on the electrical characteristics of three novel ternary compounds, Tl 3 AsSe 3 (TAS), TlGaSe 2 (TGS), and Tl 4 HgI 6 (THI), pertaining to their use as radiation detectors. The details for growth and material characterization are not presented. A semiconductor based gamma ray detector requires a material with high Z, high density, high resistivity, appropriate bandgap (1.5-2 eV), low energy/electron-hole pair, and a high μτ product. CZT is currently the best semiconductor material for room temperature gamma ray spectroscopy; however, it is extremely difficult to produce large volumes of detector grade material, making it expensive and in limited supply. DNDO/DHS began searching for other materials that might perform as well as CZT but be easier to grow and in the end lower the cost. For this purpose, we investigated the above three materials as possible replacements for CZT as gamma ray detectors. The bulk resistivity, I-V curves, X-ray response, and gamma ray response measurements for doped and undoped crystals are presented and discussed. TAS shows good X-ray and gamma ray response, but has poor resistivity, which results in large dark current and poor spectral response. TGS has good resistivity, but shows poor X-ray and gamma ray response. THI has excellent resistivity, shows some X-ray and gamma ray response, and has great potential as a gamma ray detector.

  7. Measurements of environmental gamma-ray spectra using a multi-element TL dosemeter

    International Nuclear Information System (INIS)

    Furuta, Sadaaki; Boetter-Jensen, L.; Nielsen, S.P.

    1986-12-01

    A method to estimate the energy distribution and dose of environmental gamma radiation was developed using a multielement TL dosemeter. Experimentally obtained energy responses from a multi-element TL dosemeter with different kinds of filters were used to calculate the energy distribution and related dose by the SAND-II computer code. The code was originally developed to estimate the neutron flux using a multiple foil activation method. Measurements were made at several locations with the multi-element TL dosemeter and comparisons were made with results from a NaI(Tl) scintillation detector and a high-pressure ionization chamber. (author)

  8. Development of a solid phantom prototype of Mo-99, Tc-99, and Co-57 in epoxy resins for evaluating of the uniformity in SPECT systems images

    International Nuclear Information System (INIS)

    Garcia D, O.C.; Cortes P, A.; Becerril V, A.; Garcia R, J.C.

    2002-01-01

    A manufacture method of solid phantoms prototype of resin with different radioisotopes is described. The phantom manufactured of molybdenum 99 has an uniformity of 96% determined with a Na(Tl) detector mono channel analyzer with a lead collimator of 1 cm diameter. (Author)

  9. Alpha-particle autoradiography by solid state track detectors to spatial distribution of radioactivity in alpha-counting source

    International Nuclear Information System (INIS)

    Ishigure, Nobuhito; Nakano, Takashi; Enomoto, Hiroko; Koizumi, Akira; Miyamoto, Katsuhiro

    1989-01-01

    A technique of autoradiography using solid state track detectors is described by which spatial distribution of radioactivity in an alpha-counting source can easily be visualized. As solid state track detectors, polymer of allyl diglycol carbonate was used. The advantage of the present technique was proved that alpha-emitters can be handled in the light place alone through the whole course of autoradiography, otherwise in the conventional autoradiography the alpha-emitters, which requires special carefulness from the point of radiation protection, must be handled in the dark place with difficulty. This technique was applied to rough examination of self-absorption of the plutonium source prepared by the following different methods; the source (A) was prepared by drying at room temperature, (B) by drying under an infrared lamp, (C) by drying in ammonia atmosphere after redissolving by the addition of a drop of distilled water which followed complete evaporation under an infrared lamp and (D) by drying under an infrared lamp after adding a drop of diluted neutral detergent. The difference in the spatial distributions of radioactivity could clearly be observed on the autoradiographs. For example, the source (C) showed the most diffuse distribution, which suggested that the self-absorption of this source was the smallest. The present autoradiographic observation was in accordance with the result of the alpha-spectrometry with a silicon surface-barrier detector. (author)

  10. SoLid: An innovative anti-neutrino detector for searching oscillations at the SCK•CEN BR2 reactor

    Science.gov (United States)

    Abreu, Yamiel; SoLid Collaboration

    2017-02-01

    The SoLid experiment intends to search for active-to-sterile anti-neutrino oscillations at a very short baseline from the SCK•CEN BR2 research reactor (Mol, Belgium). A novel detector approach to measure reactor anti-neutrinos was developed based on an innovative sandwich of composite polyvinyl-toluene and 6LiF:ZnS(Ag) scintillators. The system is highly segmented and read out by a network of wavelength shifting fibers and SiPM. High experimental sensitivity can be achieved compared to other standard technologies thanks to the combination of high granularity, good neutron-gamma discrimination using 6LiF:ZnS(Ag) scintillator and precise localisation of the Inverse Beta Decay products. This technology can be considered as a new generation of an anti-neutrino detector. This compact system requires limited passive shielding and relies on spatial topology to determine the different classes of backgrounds. We will describe the principle of detection and the detector design. Particular focus on the neutron discrimination will be made, as well as on the capability to use cosmic muons for channel equalisation and energy calibration. The performance of the first 288 kg SoLid module (SM1), based on the data taken at BR2 from February to September 2015, will be presented. We will conclude with the next phase, which will start in 2016, and the future plans of the experiment.

  11. SoLid: An innovative anti-neutrino detector for searching oscillations at the SCK• CEN BR2 reactor

    Energy Technology Data Exchange (ETDEWEB)

    Abreu, Yamiel, E-mail: yamiel.abreu@uantwerpen.be

    2017-02-11

    The SoLid experiment intends to search for active-to-sterile anti-neutrino oscillations at a very short baseline from the SCK• CEN BR2 research reactor (Mol, Belgium). A novel detector approach to measure reactor anti-neutrinos was developed based on an innovative sandwich of composite polyvinyl-toluene and {sup 6}LiF:ZnS(Ag) scintillators. The system is highly segmented and read out by a network of wavelength shifting fibers and SiPM. High experimental sensitivity can be achieved compared to other standard technologies thanks to the combination of high granularity, good neutron–gamma discrimination using {sup 6}LiF:ZnS(Ag) scintillator and precise localisation of the Inverse Beta Decay products. This technology can be considered as a new generation of an anti-neutrino detector. This compact system requires limited passive shielding and relies on spatial topology to determine the different classes of backgrounds. We will describe the principle of detection and the detector design. Particular focus on the neutron discrimination will be made, as well as on the capability to use cosmic muons for channel equalisation and energy calibration. The performance of the first 288 kg SoLid module (SM1), based on the data taken at BR2 from February to September 2015, will be presented. We will conclude with the next phase, which will start in 2016, and the future plans of the experiment.

  12. Thermal and x-ray studies on Tl2U(MoO4)3 and Tl4U(MoO4)4

    International Nuclear Information System (INIS)

    Dahale, N.D.; Keskar, Meera; Kulkarni, N.K.; Singh Mudher, K.D.

    2006-01-01

    In the quaternary Tl-U(IV)-Mo-O system, two new compounds namely Tl 2 U(MoO 4 ) 3 and Tl 4 U(MoO 4 ) 4 were prepared and characterized by powder X-ray diffraction and thermal methods. These compounds were prepared by solid state reactions of Tl 2 MoO 4 , UMoO 5 and MoO 3 in the required stoichiometric ratio at 500 deg C in evacuated sealed quartz ampoule. The XRD data of Tl 2 U(MoO 4 ) 3 and Tl 4 U(MoO 4 ) 4 were indexed on orthorhombic cell. TG curves of Tl 2 U(MoO 4 ) 3 and Tl 4 U(MoO 4 ) 4 did not show any weight change up to 700 deg C in an inert atmosphere. During heating in an inert atmosphere, Tl 2 U(MoO 4 ) 3 and Tl 4 U(MoO 4 ) 4 showed endothermic Dta peaks due to melting of the compounds at 519 and 565 deg C, respectively. (author)

  13. Applications of solid-state nuclear track detectors (SSNTDs) for fast ion and fusion reaction product measurements in TEXTOR experiments

    Energy Technology Data Exchange (ETDEWEB)

    Szydlowski, A.; Malinowski, K.; Malinowska, A. [Association EURTOM-IPPLM Warsaw, The Andrzej Soltan Institute for Nuclear Studies, 05-400 Otwock-Swierk (Poland); Wassenhove, G. Van [EURATOM-Belgium State Association, LPP, ERM/KMS, Trilateral Euregio Cluster, B-1000 Brussels (Belgium); Schweer, B. [Association EURATOM-FZJ, Institutte of Plasma Physicx, Juelich (Germany)

    2011-07-01

    Full text of publication follows: The paper reports on measurements of fusion reaction protons which were performed on TEXTOR facility in January 2009. The basic experimental scheme was similar to that applied in the previous measurements [1, 2]. The main experimental tool equipment was a small ion pinhole camera which was equipped with a PM-355 detector sample and was attached to a water cooled manipulator. The camera was placed below the plasma ring in the direction of ion drifts, at a distance of 4.4 cm from LCFS. However, in the described experiment it was aligned at an angle to the mayor TEXTOR radius (contrary to previous experiments), so that the input pinhole was oriented first at {gamma} = 45 degrees (shots 108799 - 108818) and then {gamma} = 600 (shots 108832 - 108847). The discharges were executed with one neutral beam of the total power 0.6 - 1.0 MW. In the first series (Nos 108799 - 108818) the plasma was additionally heated by ICRH of frequency 38 MHz. The irradiated detector samples were subjected to the same interrupted etching procedure as the samples used in the CR-39/PM-355 detector calibration measurements [1, 2]. After that, track density distributions and track diameter histograms were measured under an optical microscope. By the use of the calibration curves, it was possible to distinguish craters produced by protons from other craters and to convert the obtained histograms into proton energy spectra. The craters induced by lower energy ions appeared to be concentrated in narrower areas, whereas higher energy ions were registered in a more diffused detector fields. The paper shows again that the CR-39/PM-355 detector is an useful diagnostic tool for tokamak experiments, for measurement of charged ions. References: [1] A. Szydlowski, A. Malinowska, M. Jaskola, A. Korman, M.J. Sadowski, G. Van Wassenhove, B. Schweer and the TEXTOR team, A. Galkowski, 'Application of Solid State Nuclear Track Detectors in TEXTOR Experiment for Measurements

  14. Phase diagrams of novel Tl{sub 4}SnSe{sub 4}–TlSbSe{sub 2}–Tl{sub 2}SnSe{sub 3} quasi-ternary system following DTA and X-ray diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Barchiy, I.E.; Tatzkar, A.R. [Department of Chemistry, Uzhgorod National University, Pidgirna St., 46, Uzhgorod 88000 (Ukraine); Fedorchuk, A.O. [Department of Inorganic and Organic Chemistry, Lviv National University of Veterinary Medicine and Biotechnologies, Pekarska St., 50, Lviv 79010 (Ukraine); Plucinski, K., E-mail: kpluc2006@wp.pl [Electronics Department, Military University Technology, Warsaw, Kaliskiego 2, Warsaw 00-908 (Poland)

    2016-06-25

    Phase relation in the Tl{sub 4}SnSe{sub 4}–TlSbSe{sub 2}–Tl{sub 2}SnSe{sub 3} quasiternary system were studied by the DTA and X-ray diffraction in combination with mathematical modeling. The phase diagrams of the Tl{sub 4}SnSe{sub 4}–TlSbSe{sub 2} and Tl{sub 2}SnSe{sub 3}–TlSbSe{sub 2} systems, the perspective views of the phase interaction in the ternary system, the liquidus surface projection, the isothermal section at 423 K were built for the first time. The Tl{sub 4}SnSe{sub 4}–TlSbSe{sub 2}–Tl{sub 2}SnSe{sub 3} system is of the invariant eutectic type and is characterized by the formation of limited solid solutions following initial ternary compounds. New complex compounds are not formed. - Highlights: • Two Tl{sub 4}SnSe{sub 4}–TlSbSe{sub 2},Tl{sub 2}SnSe{sub 3}–TlSbSe{sub 2} systems were explored. • Invariant processes in the ternary system were determined. • New complex compounds were not observed in ternary system.

  15. Solid-state photo-detectors for both CT and PET applications

    CERN Document Server

    Moraes, Danielle; Jarron, Pierre

    2007-01-01

    New semiconductor detectors have recently gained a lot of attention for medical applications in general. Advances in CdZnTe-detector arrays might improve both energy resolution and spatial resolution of clinical X-ray systems. Alternative system designs based on TFA technology combining photo-detector arrays with CMOS electronics open a possibility for compact imaging cameras. This scenario allows for the use of alternative materials such as a-Si:H and HgI2 that can be applied alone or integrated with scintillators. Results obtained with such materials are presented.

  16. ZnO nanoneedle/H2O solid-liquid heterojunction-based self-powered ultraviolet detector

    Science.gov (United States)

    2013-01-01

    ZnO nanoneedle arrays were grown vertically on a fluorine-doped tin oxide-coated glass by hydrothermal method at a relatively low temperature. A self-powered photoelectrochemical cell-type UV detector was fabricated using the ZnO nanoneedles as the active photoanode and H2O as the electrolyte. This solid-liquid heterojunction offers an enlarged ZnO/water contact area and a direct pathway for electron transport simultaneously. By connecting this UV photodetector to an ammeter, the intensity of UV light can be quantified using the output short-circuit photocurrent without a power source. High photosensitivity, excellent spectral selectivity, and fast photoresponse at zero bias are observed in this UV detector. The self-powered behavior can be well explained by the formation of a space charge layer near the interface of the solid-liquid heterojunction, which results in a built-in potential and makes the solid-liquid heterojunction work in photovoltaic mode. PMID:24103153

  17. X-ray absorption spectroscopy of diluted system by undulator photon source and multi-element solid-state detector

    CERN Document Server

    Tanida, H

    2001-01-01

    In order to measure the extended X-ray absorption fine structure (EXAFS) spectrum of an ultra-diluted system, an optics and detector control system for a synchrotron radiation beamline is developed. The undulator gap width is continuously tuned to obtain the maximum X-ray photon flux during the energy scan for the EXAFS measurement. A piezoelectric translator optimizes the parallelism of the double crystal in a monochromator at each measurement point to compensate for mechanical errors of the monochromator, resulting in a smooth and intense X-ray photon flux during the measurement. For a detection of a weak fluorescence signal from diluted samples, a 19-element solid-state detector and digital signal processor are used. A K-edge EXAFS spectrum of iron in a myoglobin aqueous solution with a concentration of 5.58 parts per million was obtained by this system.

  18. Spectral measurements of loess TL

    International Nuclear Information System (INIS)

    Rendell, H.M.; Mann, S.J.; Townsend, P.D.

    1988-01-01

    Variations in thermoluminescence (TL) glow curves are reported for two loess samples when examined with broad band filters in the range 275-650 nm. Samples show striking differences in bleaching behaviour, when their TL emissions are observed in the u.v., blue, green and yellow spectral regions. The age estimates, given by the equivalent dose (ED) values, differ by up to a factor of two for analyses using the green and u.v. TL signals. These ED values also vary with prolonged room temperature storage between the bleaching and irradiation steps. The anomalies in the bleaching behaviour are interpreted in terms of changes in TL efficiency. The results have major implications for the regeneration method of TL dating for these fine-grained sediments and suggest that reliable dates obtained by it may be fortuitous. (author)

  19. Radon diffusion studies in some building materials using solid state nuclear track detectors

    CERN Document Server

    Singh, S; Singh, B; Singh, J

    1999-01-01

    LR-115 plastic track detector has been used to study radon diffusion through some building materials, viz. cement, soil, marble chips, sand and lime as well as air. Diffusion constant and diffusion length is calculated for all these materials.

  20. 201Tl heart studies

    International Nuclear Information System (INIS)

    Bell, R.L.

    1976-01-01

    At the annual meeting of the Society of Nuclear Medicine there was a preponderance of papers dealing with the heart. The most impressive papers detailed the use of monovalent cation 201 Tl in the evaluation of coronary artery disease. Thallium-201 behaves like potassium in that it enters heart muscle quickly and persists in that organ for several hours. It is unlike most radioactive potassium analogues used for heart studies in that: (1) its gamma energy peaks (69 keV and 80 keV) are more easily collimated with resultant image improvement, (2) its physical half life of 72 hours is sufficiently short to attain high counting rates without too much radiation and is sufficiently long so that storage is not prohibitive, (3) its short half life and lack of Beta radiation results in lower radiation to the patient, and (4) its uptake in heart is greater and uptake in liver and stomach less than other potassium analogues

  1. Discrimination of Charged Particles in a Neutral Beam Line by Using a Solid Scintillation Detector

    Energy Technology Data Exchange (ETDEWEB)

    Woo, Jong-Kwan; Ko, Jewou; Liu, Dong [Jeju National University, Jeju (Korea, Republic of)

    2017-01-15

    In the past several decades, many studies have been conducted to search for non-baryonic dark matter, such as weakly interactive massive particles (WIMPs). In the search for WIMPs, charged particles incident on the detector are background particles because WIMPs are neutral. Charged particles originate from various sources, such as cosmic rays and laboratory materials surrounding the main detector. Therefore, a veto that discriminates charged particles can improve the particle detection efficiency of the entire experiment for detecting WIMPs. Here, we investigate in the thickness range of 1 mm to 5 mm, the optimal thickness of a polystyrene scintillator as a charged particle veto detector. We found that 3-mm-thick polystyrene provides the best performance to veto charged particles and the charged-particle background in the search for the WIMP signal. Furthermore, we fabricated 3-mm-thick and 5-mm-thick polystyrene charged particle veto detectors that will be used in an underground laboratory in the search for WIMP dark matter. After exposing those detectors are the actual beam line, we compared the rate of charged particles measured using those detectors and the rate simulated through a Monte Carlo simulation.

  2. A Monte Carlo based development of a cavity theory for solid state detectors irradiated in electron beams

    International Nuclear Information System (INIS)

    Mobit, P.

    2002-01-01

    Recent Monte Carlo simulations have shown that the assumption in the small cavity theory (and the extension of the small cavity theory by Spencer-Attix) that the cavity does not perturb the electron fluence is seriously flawed. For depths beyond d max not only is there a significant difference between the energy spectra in the medium and in the solid cavity materials but there is also a significant difference in the number of low-energy electrons which cannot travel across the solid cavity and hence deposit their dose in it (i.e. stopper electrons whose residual range is less than the cavity thickness). The number of these low-energy electrons that are not able to travel across the solid state cavity increases with depth and effective thickness of the detector. This also invalidates the assumption in the small cavity theory that most of the dose deposited in a small cavity is delivered by crossers. Based on Monte Carlo simulations, a new cavity theory for solid state detectors irradiated in electron beams has been proposed as: D med (p)=D det (p) x s S-A med.det x gamma(p) e x S T , where D med (p) is the dose to the medium at point, p, D det (p) is the average detector dose to the same point, s S-A med.det is the Spencer-Attix mass collision stopping power ratio of the medium to the detector material, gamma(p) e is the electron fluence perturbation correction factor and S T is a stopper-to-crosser correction factor to correct for the dependence of the stopper-to-crosser ratio on depth and the effective cavity size. Monte Carlo simulations have been computed for all the terms in this equation. The new cavity theory has been tested against the Spencer-Attix cavity equation as the small cavity limiting case and also Monte Carlo simulations. The agreement between this new cavity theory and Monte Carlo simulations is within 0.3%. (author)

  3. Contribution to the study of radio toxicity of aromatic and medicinal plants using solid state nuclear track detectors

    International Nuclear Information System (INIS)

    Mortassim, A.; Misdaq, M.A.; Naaman, A

    2009-01-01

    The concentrations of uranium (238 U), thorium (232 Th), radon (222 Rn) and thoron (220 Rn) were measured in twenty aromatic and medicinal plants in f ind a new method based on using solid state nuclear track detectors type Cr-39 and Rs-115. He emerges from this study that the verbena and salvia have higher levels of uranium (radon) higher than that of other plants while the leaves of olive and saturja have concentrations of thorium (thoron) higher than other plants therefore radio toxicity of these plants is higher than that of others and may pose a radiological hazard if the masses are incorporated by consumers high. [fr

  4. Measurement of volumic activities of radon in air in houses and in working rooms with solid state nuclear track detectors

    International Nuclear Information System (INIS)

    Hakam, O.K.

    1993-01-01

    In this work, a new method of measuring volumic activity of radon has been developed. This method is based on using solid state nuclear track detectors LR-115 type II. It has been applied to measurement of volumic activities of radon in air in houses and in working rooms in different regions of Morocco. These measurements, carried out for the first time in the country, allowed to estimate the dose equivalents of radon received by the population of the studied regions. 59 refs., 38 figs., 38 tabs. (F.M.)

  5. Portable in situ NaI(Tl) γ spectroscopy system

    International Nuclear Information System (INIS)

    Wang Bairong; Dong Binjiang; Zeng Liping; Shen Tingyun

    2000-01-01

    The author describes a portable in situ NaI(Tl) γ spectroscopy system, which consists of a NaI (Tl) scintillation detector, an integrative spectroscopy card, a notebook computer and spectroscopy software. The spectrometer addresses applications in environmental or nuclear accident in situ γ spectroscopy measurements, and gives valid quantitative results of radionuclide concentrations per unit volume (Bq/kg) or unit area (Bq/cm 2 ) in the soil and absorbed dose rate in air at 1 m above ground (Gy/h)

  6. Pulse shape analysis using CsI(Tl) Crystals

    International Nuclear Information System (INIS)

    Silva, J.; Fiori, E.; Loher, B.; Savran, D.; Wirth, R.; Vencelj, M.

    2013-06-01

    The decay time of CsI(Tl) scintillating material consists of more than a single exponential component. The ratio between the intensity of these components varies as a function of the ionizing power of the absorbed particles, such as γ -rays or protons, and the temperature. This property can therefore be used for particle discrimination and for temperature monitoring, using pulse shape analysis. An unsupervised method that uses fuzzy clustering algorithms for particle identification based on pulse shape analysis is presented. The method is applied to discriminate between photon and proton-induced signals in CsI(Tl) scintillator detectors. The first results of a method that uses pulse shape analysis for correcting the temperature-dependent gain effect of the detector are also presented. The method aims at conserving a good energy resolution in a temperature varying environment without the need to measure the temperature of the detector externally (authors)

  7. Tl and OSL on diopside crystal

    International Nuclear Information System (INIS)

    Cano, N.F.; Watanabe, S.; Mittani, J.C.R.; Yukihara, E.G.

    2006-01-01

    The diopside with chemical composition CaMgSi 2 O 6 is part of an important solid solution series of the pyroxene group. The mineral is commonly found in meteorites and it is an important rock forming mineral of medium and high grade metamorphic rocks which are rich in calcium. In the bibliography it is possible to found several studies on electron spin resonance (ESR), reflectance, etc. but not on thermoluminescence (TL) or optically stimulated luminescence (OSL). In the present work we studied diopside TL and OSL behaviour on natural and natural irradiated samples. The sample used in our study is a white coloured diopside provided by Mineracao Sao Judas located in Sao Paulo, Brazil. The X-Ray Fluorescence technique has shown high concentrations of SiO 2 (55.81 % mol), CaO (23.47 % mol), MgO (18.03 % mol), Al 2 O 3 (1.56 % mol), Fe 2 O 3 (0.53 % mol), K 2 O (0.44 % mol), TiO 2 (0.065 % mol), P 2 O 5 (0.026 % mol), and MnO (0.013 % mol). TL measurements on natural samples show four TL peaks at 160, 260, 360, and 450 C. After beta-irradiation an increment mainly in the low temperature peaks is observed. As for OSL measurements, low OSL signal was observed on natural samples using blue light stimulation and UV detection. The intensity of the signal was observed to increase with the irradiation dose. (Author)

  8. Needle Type Solid State Detectors for In-Vivo Measurement of Tracer Activity

    Energy Technology Data Exchange (ETDEWEB)

    Lauber, A [AB Atomenergi, Nykoeping (Sweden); Wolgast, W [Univ. of Uppsala (Sweden). Inst. of Physiology and Medical Biophysics

    1970-07-15

    A set of miniature detector probes for in-vivo-measurement of beta and gamma tracer activity is described. The probes use a lithium-compensated p-i-n silicon detector as sensing element. The standard 'needle probe' contains a cylindrical detector 0.9 mm in diameter and 3 mm long, enclosed in a stainless steel tube 1.1 mm in outer diameter and with walls 0. 05 mm thick. For particular applications several modified types have been developed: probes with larger sensing elements, probes with extra thin walls for low-energy beta detection, probes with two or three sensing elements in the same needle and probes containing a movable sensing element. This report describes the construction and the properties of the different needle probes.

  9. Trends in the design of front-end systems for room temperature solid state detectors

    International Nuclear Information System (INIS)

    Manfredi, Pier F.; Re, Valerio

    2003-01-01

    The paper discusses the present trends in the design of low-noise front-end systems for room temperature semiconductor detectors. The technological advancement provided by submicron CMOS and BiCMOS processes is examined from several points of view. The noise performances are a fundamental issue in most detector applications and suitable attention is devoted to them for the purpose of judging whether or not the present processes supersede the solutions featuring a field-effect transistor as a front-end element. However, other considerations are also important in judging how well a monolithic technology suits the front-end design. Among them, the way a technology lends itself to the realization of additional functions, for instance, the charge reset in a charge-sensitive loop or the time-variant filters featuring the special weighting functions that may be requested in some applications of CdTe or CZT detectors

  10. Needle Type Solid State Detectors for In-Vivo Measurement of Tracer Activity

    International Nuclear Information System (INIS)

    Lauber, A.; Wolgast, W.

    1970-07-01

    A set of miniature detector probes for in-vivo-measurement of beta and gamma tracer activity is described. The probes use a lithium-compensated p-i-n silicon detector as sensing element. The standard 'needle probe' contains a cylindrical detector 0.9 mm in diameter and 3 mm long, enclosed in a stainless steel tube 1.1 mm in outer diameter and with walls 0. 05 mm thick. For particular applications several modified types have been developed: probes with larger sensing elements, probes with extra thin walls for low-energy beta detection, probes with two or three sensing elements in the same needle and probes containing a movable sensing element. This report describes the construction and the properties of the different needle probes

  11. Identification of charged particles by etching the solid state nuclear track detectors in successive intervals

    International Nuclear Information System (INIS)

    Randhawa, G.S.; Virk, H.S.

    1997-01-01

    The suitability of the method of charged particle identification by etching the samples in successive intervals developed by Grabez et al. has been checked in CR-39 exposed to heavy ions 238 U, 208 Pb, 197 Au and 132 Xe in the interval 11.0 to 17.0 MeV/u. A similar study has been made on soda glass detectors irradiated by 238 U, 132 Xe, 56 Fe and 48 Ti ions having energy 4.0 to 6.0 MeV/u. It is concluded that this method of particle identification can be used successfully in CR-39 and soda glass detectors. (author)

  12. A compact solid-state detector for small angle particle tracking

    Energy Technology Data Exchange (ETDEWEB)

    Altieri, S.; Barnaba, O.; Braghieri, A. E-mail: alessandro.braghieri@pv.infn.it; Cambiaghi, M.; Lanza, A.; Locatelli, T.; Panzeri, A.; Pedroni, P.; Pinelli, T.; Jennewein, P.; Lang, M.; Preobrazhensky, I.; Annand, J.R.M.; Sadiq, F

    2000-09-21

    MIcrostrip Detector Array System (MIDAS) is a compact silicon-tracking telescope for charged particles emitted at small angles in intermediate energy photonuclear reactions. It was realized to increase the angular acceptance of the DAPHNE detector and used in an experimental program to check the Gerasimov-Drell-Hearn sum rule at the Mainz electron microtron (MAMI). MIDAS provides a trigger for charged hadrons, p/{pi}{sup {+-}} identification and particle tracking in the region 7 deg. <{theta}<16 deg.. In this paper we present the main characteristics of MIDAS and its measured performances.

  13. A compact solid-state detector for small angle particle tracking

    International Nuclear Information System (INIS)

    Altieri, S.; Barnaba, O.; Braghieri, A.; Cambiaghi, M.; Lanza, A.; Locatelli, T.; Panzeri, A.; Pedroni, P.; Pinelli, T.; Jennewein, P.; Lang, M.; Preobrazhensky, I.; Annand, J.R.M.; Sadiq, F.

    2000-01-01

    MIcrostrip Detector Array System (MIDAS) is a compact silicon-tracking telescope for charged particles emitted at small angles in intermediate energy photonuclear reactions. It was realized to increase the angular acceptance of the DAPHNE detector and used in an experimental program to check the Gerasimov-Drell-Hearn sum rule at the Mainz electron microtron (MAMI). MIDAS provides a trigger for charged hadrons, p/π ± identification and particle tracking in the region 7 deg. <θ<16 deg.. In this paper we present the main characteristics of MIDAS and its measured performances

  14. Solid-state radiation detectors for active personal dosimetry and radiations source tracking

    International Nuclear Information System (INIS)

    Talpalariu, Corneliu; Talpalariu, Jeni; Matei, Corina; Lita, Ioan; Popescu, Oana

    2010-01-01

    We report on the design of the readout electronics using PIN diode radiation detector of 5 mm thickness for nuclear safety and active personal dosimetry. Our effort consisted in designing and fabricating the electronics to reflect the needs of gamma radiations dosimetry and hybrids PIN diode arrays for charged particle detectors. We report results obtained during testing and characterizing the new devices in gamma fields, operating at room temperature. There were determined the energy spectrum resolution, radiation hardness and readout rate. Also, data recording methods and parallel acquisition problems from a transducer matrix are presented. (authors)

  15. MOS solid-state detector arrays for x-ray imaging

    International Nuclear Information System (INIS)

    Koppel, L.N.

    1977-01-01

    Two types of MOS detector arrays were used to sense directly patterns of soft x-rays, in the Lawrence Livermore Laboratory experimental laser-fusion program. A linear self-scanning photodiode array (SSPA) is used in a wave-length-dispersive spectrometer. A frame transfer charge-coupled device (CCD) facilitates the use of an x-ray microscope. Measurements and calculations of the x-ray sensitivity of these devices are presented. Their linearity and dynamic range are discussed, as well as data recovery systems for each detector. Experiences in using these devices to detect pulses of x-rays in laser-fusion experiments are described

  16. Absolute activity measurements with the windowless 4π-CsI(Tl)-sandwich spectrometer

    International Nuclear Information System (INIS)

    Denecke, B.

    1994-01-01

    The windowless 4π-CsI(Tl)-sandwich spectrometer consists of two scintillation crystals sandwiching radioactive sources deposited on thin plastic foils. This configuration has a solid angle very close to 4π sr. The detectors are sensitive to charged particles with energies > 15 keV and measure photons of 15-200 keV with a probability > 98%. Disintegration rates of samples of radionuclides with complex decay modes can be determined directly from the measured count rates with uncertainties below 0.3%. Radionuclide solutions of 57 Co, 109 Cd, 125 I, 152 Eu and 192 Ir were standardised, partly in the framework of international comparisons. A detailed description of the spectrometer and the measurement procedure is given. (orig.)

  17. Absolute activity measurements with the windowless 4π-CsI(Tl)-sandwich spectrometer

    Science.gov (United States)

    Denecke, B.

    1994-01-01

    The windowless 4π-CsI(Tl)-sandwich spectrometer consists of two scintillation crystals sandwiching radioactive sources deposited on thin plastic foils. This configuration has a solid angle very close to 4π sr. The detectors are sensitive to charged particles with energies > 15 keV and measure photons of 15-200 keV with a probability > 98%. Disintegration rates of samples of radionuclides with complex decay modes can be determined directly from the measured count rates with uncertainties below 0.3%. Radionuclide solutions of 57Co, 109Cd, 125I, 152Eu and 192Ir were standardised, partly in the framework of international comparisons. A detailed description of the spectrometer and the measurement procedure is given.

  18. Deformation effects in electronic spectra of the layered semiconductors TlGaS sub 2 , TlGaSe sub 2 and TlInS sub 2

    CERN Document Server

    Allakhverdiev, K R; Suleymanov, R A; Gasanov, N Z

    2003-01-01

    The deformation effects in electronic spectra of the ternary layered semiconductors TlGaS sub 2 , TlGaSe sub 2 and TlInS sub 2 are considered. It is shown that the influence of hydrostatic pressure, thermal expansion and variation of composition in solid solutions on the band gap of the crystals investigated can be described in the framework of one common model of deformation potentials. This model appears to be close to that of layered semiconductors of the A sub 3 B sub 6 group, attesting to the fact that the main principles of formation of band structure in these two groups of layered crystals are the same.

  19. Time-Resolved Diffuse Optical Spectroscopy and Imaging Using Solid-State Detectors: Characteristics, Present Status, and Research Challenges.

    Science.gov (United States)

    Alayed, Mrwan; Deen, M Jamal

    2017-09-14

    Diffuse optical spectroscopy (DOS) and diffuse optical imaging (DOI) are emerging non-invasive imaging modalities that have wide spread potential applications in many fields, particularly for structural and functional imaging in medicine. In this article, we review time-resolved diffuse optical imaging (TR-DOI) systems using solid-state detectors with a special focus on Single-Photon Avalanche Diodes (SPADs) and Silicon Photomultipliers (SiPMs). These TR-DOI systems can be categorized into two types based on the operation mode of the detector (free-running or time-gated). For the TR-DOI prototypes, the physical concepts, main components, figures-of-merit of detectors, and evaluation parameters are described. The performance of TR-DOI prototypes is evaluated according to the parameters used in common protocols to test DOI systems particularly basic instrumental performance (BIP). In addition, the potential features of SPADs and SiPMs to improve TR-DOI systems and expand their applications in the foreseeable future are discussed. Lastly, research challenges and future developments for TR-DOI are discussed for each component in the prototype separately and also for the entire system.

  20. Calibration of solid state nuclear track detectors at high energy ion beams for cosmic radiation measurements: HAMLET results

    International Nuclear Information System (INIS)

    Szabó, J.; Pálfalvi, J.K.

    2012-01-01

    The MATROSHKA experiments and the related HAMLET project funded by the European Commission aimed to study the dose burden of the crew working on the International Space Station (ISS). During these experiments a human phantom equipped with several thousands of radiation detectors was exposed to cosmic rays inside and outside the ISS. Besides the measurements realized in Earth orbit, the HAMLET project included also a ground-based program of calibration and intercomparison of the different detectors applied by the participating groups using high-energy ion beams. The Space Dosimetry Group of the Centre for Energy Research (formerly Atomic Energy Research Institute) participated in these experiments with passive solid state nuclear track detectors (SSNTDs). The paper presents the results of the calibration experiments performed in the years 2008–2011 at the Heavy Ion Medical Accelerator (HIMAC) of the National Institute of Radiological Sciences (NIRS), Chiba, Japan. The data obtained serve as update and improvement for the previous calibration curves which are necessary for the evaluation of the SSNTDs exposed in unknown space radiation fields.

  1. Calibration of solid state nuclear track detectors at high energy ion beams for cosmic radiation measurements: HAMLET results

    Energy Technology Data Exchange (ETDEWEB)

    Szabo, J., E-mail: julianna.szabo@energia.mta.hu [Hungarian Academy of Sciences, Centre for Energy Research, Konkoly Thege Miklos ut 29-33, 1525 Budapest 114, P.O. Box 49 (Hungary); Palfalvi, J.K. [Hungarian Academy of Sciences, Centre for Energy Research, Konkoly Thege Miklos ut 29-33, 1525 Budapest 114, P.O. Box 49 (Hungary)

    2012-12-01

    The MATROSHKA experiments and the related HAMLET project funded by the European Commission aimed to study the dose burden of the crew working on the International Space Station (ISS). During these experiments a human phantom equipped with several thousands of radiation detectors was exposed to cosmic rays inside and outside the ISS. Besides the measurements realized in Earth orbit, the HAMLET project included also a ground-based program of calibration and intercomparison of the different detectors applied by the participating groups using high-energy ion beams. The Space Dosimetry Group of the Centre for Energy Research (formerly Atomic Energy Research Institute) participated in these experiments with passive solid state nuclear track detectors (SSNTDs). The paper presents the results of the calibration experiments performed in the years 2008-2011 at the Heavy Ion Medical Accelerator (HIMAC) of the National Institute of Radiological Sciences (NIRS), Chiba, Japan. The data obtained serve as update and improvement for the previous calibration curves which are necessary for the evaluation of the SSNTDs exposed in unknown space radiation fields.

  2. A new large solid angle multi-element silicon drift detector system for low energy X-ray fluorescence spectroscopy

    Science.gov (United States)

    Bufon, J.; Schillani, S.; Altissimo, M.; Bellutti, P.; Bertuccio, G.; Billè, F.; Borghes, R.; Borghi, G.; Cautero, G.; Cirrincione, D.; Fabiani, S.; Ficorella, F.; Gandola, M.; Gianoncelli, A.; Giuressi, D.; Kourousias, G.; Mele, F.; Menk, R. H.; Picciotto, A.; Rachevski, A.; Rashevskaya, I.; Sammartini, M.; Stolfa, A.; Zampa, G.; Zampa, N.; Zorzi, N.; Vacchi, A.

    2018-03-01

    Low-energy X-ray fluorescence (LEXRF) is an essential tool for bio-related research of organic samples, whose composition is dominated by light elements. Working at energies below 2 keV and being able to detect fluorescence photons of lightweight elements such as carbon (277 eV) is still a challenge, since it requires in-vacuum operations to avoid in-air photon absorption. Moreover, the detectors must have a thin entrance window and collect photons at an angle of incidence near 90 degrees to minimize the absorption by the protective coating. Considering the low fluorescence yield of light elements, it is important to cover a substantial part of the solid angle detecting ideally all emitted X-ray fluorescence (XRF) photons. Furthermore, the energy resolution of the detection system should be close to the Fano limit in order to discriminate elements whose XRF emission lines are often very close within the energy spectra. To ensure all these features, a system consisting of four monolithic multi-element silicon drift detectors was developed. The use of four separate detector units allows optimizing the incidence angle on all the sensor elements. The multi-element approach in turn provides a lower leakage current on each anode, which, in combination with ultra-low noise preamplifiers, is necessary to achieve an energy resolution close to the Fano limit. The potential of the new detection system and its applicability for typical LEXRF applications has been proved on the Elettra TwinMic beamline.

  3. Enriched Boron-Doped Amorphous Selenium Based Position-Sensitive Solid-State Thermal Neutron Detector for MPACT Applications

    Energy Technology Data Exchange (ETDEWEB)

    Mandal, Krishna [Univ. of South Carolina, Columbia, SC (United States)

    2017-09-29

    High-efficiency thermal neutron detectors with compact size, low power-rating and high spatial, temporal and energy resolution are essential to execute non-proliferation and safeguard protocols. The demands of such detector are not fully covered by the current detection system such as gas proportional counters or scintillator-photomultiplier tube combinations, which are limited by their detection efficiency, stability of response, speed of operation, and physical size. Furthermore, world-wide shortage of 3He gas, required for widely used gas detection method, has further prompted to design an alternative system. Therefore, a solid-state neutron detection system without the requirement of 3He will be very desirable. To address the above technology gap, we had proposed to develop new room temperature solidstate thermal neutron detectors based on enriched boron (10B) and enriched lithium (6Li) doped amorphous Se (As- 0.52%, Cl 5 ppm) semiconductor for MPACT applications. The proposed alloy materials have been identified for its many favorable characteristics - a wide bandgap (~2.2 eV at 300 K) for room temperature operation, high glass transition temperature (tg ~ 85°C), a high thermal neutron cross-section (for boron ~ 3840 barns, for lithium ~ 940 barns, 1 barn = 10-24 cm2), low effective atomic number of Se for small gamma ray sensitivity, and high radiation tolerance due to its amorphous structure.

  4. Enriched Boron-Doped Amorphous Selenium Based Position-Sensitive Solid-State Thermal Neutron Detector for MPACT Applications

    International Nuclear Information System (INIS)

    Mandal, Krishna

    2017-01-01

    High-efficiency thermal neutron detectors with compact size, low power-rating and high spatial, temporal and energy resolution are essential to execute non-proliferation and safeguard protocols. The demands of such detector are not fully covered by the current detection system such as gas proportional counters or scintillator-photomultiplier tube combinations, which are limited by their detection efficiency, stability of response, speed of operation, and physical size. Furthermore, world-wide shortage of 3 He gas, required for widely used gas detection method, has further prompted to design an alternative system. Therefore, a solid-state neutron detection system without the requirement of 3 He will be very desirable. To address the above technology gap, we had proposed to develop new room temperature solidstate thermal neutron detectors based on enriched boron ( 10 B) and enriched lithium ( 6 Li) doped amorphous Se (As- 0.52%, Cl 5 ppm) semiconductor for MPACT applications. The proposed alloy materials have been identified for its many favorable characteristics - a wide bandgap (~2.2 eV at 300 K) for room temperature operation, high glass transition temperature (t g ~ 85°C), a high thermal neutron cross-section (for boron ~ 3840 barns, for lithium ~ 940 barns, 1 barn = 10 -24 cm 2 ), low effective atomic number of Se for small gamma ray sensitivity, and high radiation tolerance due to its amorphous structure.

  5. Stability of detecting system using NaI(Tl)

    International Nuclear Information System (INIS)

    Zhuo Yunshang; Lei Zhangyun; Zen Yu; Gong Hua

    1996-01-01

    A detecting system using NaI(Tl) is widely used in research and industry of nuclear science and other fields. For providing the high accuracy and working well under inclement environment, the stability of detecting system using NaI(Tl) is very important. The variation of environment temperature, the change of counting rate and long time continuous working of detector will cause un-negligible effect on the measurement. Three approaches were used. They are: 1) temperature control (It makes the effect of the variation of environment temperature on the measurement negligible.); 2) spectrum stabilizing (It adjust the peak position of the spectrum when the counting rate changes.); and 3) auto-checking and adjusting (It adjusts the drift of the NaI(Tl) detecting system when it works continuously)

  6. Differential diagnosis of thyroid diseases with 131I and 201TlCl scintigraphy

    International Nuclear Information System (INIS)

    Kumano, Machiko; Ishida, Osamu

    1979-01-01

    Scintigraphic study with 131 I and 201 TlCl was performed on the differential diagnosis of various kinds of thyroid disease. When thyroid nodules are cold by scintigraphy with 131 I and hot with 201 TlCl, the lesions were proved to be solid tumor, that is, mostly follicular adenoma and carcinoma, and also most probably chronic thyroiditis. Accumulation of 201 TlCl, however, is not observed in cystic lesions, and is very high with high frequency in metastatic lesion of the lymph nodes as well as the thyroid cancer, especially in well differentiated follicular carcinoma. Therefore 201 TlCl was very useful to confirm the metastatic tumors from the thyroid cancer. These features in accumulation of 131 I and 201 TlCl in thyroid disease suggest the imaging technique with 201 TlCl combined with 131 I seem to provide more pathological information on the thyroid and metastatic lesions. (author)

  7. The former tests realized to a personal neutron dosemeter based on solid nuclear tracks detector; Primeras pruebas realizadas a un dosimetro personal de neutrones basado en detectores solidos de trazas nucleares

    Energy Technology Data Exchange (ETDEWEB)

    Camacho, M.E.; Tavera, L.; Balcazar, M. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    1997-07-01

    Due to the increase in the use of neutron radiation a personal neutron dosemeter based on solid nuclear tracks detector (DSTN) was designed and constructed. The personal dosemeter design consists of three arrangements. The first one consists of a plastic nuclear tracks detector (LR115 or CR39) in contact with a LiF pellet. The second one is the same that above but it placed among two cadmium pellets and, the third one is formed by the alone detector without converter neither neutron absorber. The three arrangements are placed inside a plastic porta detector hermetically closed to avoid the bottom produced by environmental radon whichever both detectors (LR115 and CR39) are sensitive. In this work the former tests realized to that dosemeter are presented. (Author)

  8. Room Temperature Hard Radiation Detectors Based on Solid State Compound Semiconductors: An Overview

    Science.gov (United States)

    Mirzaei, Ali; Huh, Jeung-Soo; Kim, Sang Sub; Kim, Hyoun Woo

    2018-05-01

    Si and Ge single crystals are the most common semiconductor radiation detectors. However, they need to work at cryogenic temperatures to decrease their noise levels. In contrast, compound semiconductors can be operated at room temperature due to their ability to grow compound materials with tunable densities, band gaps and atomic numbers. Highly efficient room temperature hard radiation detectors can be utilized in biomedical diagnostics, nuclear safety and homeland security applications. In this review, we discuss room temperature compound semiconductors. Since the field of radiation detection is broad and a discussion of all compound materials for radiation sensing is impossible, we discuss the most important materials for the detection of hard radiation with a focus on binary heavy metal semiconductors and ternary and quaternary chalcogenide compounds.

  9. Review of the state of the art in personnel neutron monitoring with solid state detectors

    International Nuclear Information System (INIS)

    Griffith, R.V.

    1987-01-01

    Albedo systems are the mainstay at many facilities and continue to be refined. Advanced electrochemical etching techniques for CR-39 now yield a dose equivalent response that is nearly constant from 0.1 to 4.0 MeV. Recent studies include use of converters to enhance CR-39 response at both low and high energies. Methods have been suggested for use of CR-39, either alone or in conjunction with albedo and other detectors to provide spectral information as a step to more accurate dosimetry. Limitations in the use of CR-39 primarily center on the lack of consistent, high-quality, dosimetry-grade material, significant angular dependence, and poor dose equivalent response at both low and high energies. Work continues on silicon diodes, with some new designs. The most attractive new dosimetry technique is the bubble-damage or superheated drop detector. Metal-on-silicon (MOS) microelectronics present exciting possibilities for the future. 25 refs., 6 figs

  10. Room Temperature Hard Radiation Detectors Based on Solid State Compound Semiconductors: An Overview

    Science.gov (United States)

    Mirzaei, Ali; Huh, Jeung-Soo; Kim, Sang Sub; Kim, Hyoun Woo

    2018-03-01

    Si and Ge single crystals are the most common semiconductor radiation detectors. However, they need to work at cryogenic temperatures to decrease their noise levels. In contrast, compound semiconductors can be operated at room temperature due to their ability to grow compound materials with tunable densities, band gaps and atomic numbers. Highly efficient room temperature hard radiation detectors can be utilized in biomedical diagnostics, nuclear safety and homeland security applications. In this review, we discuss room temperature compound semiconductors. Since the field of radiation detection is broad and a discussion of all compound materials for radiation sensing is impossible, we discuss the most important materials for the detection of hard radiation with a focus on binary heavy metal semiconductors and ternary and quaternary chalcogenide compounds.

  11. Analysis of the charge collection process in solid state X-ray detectors

    Energy Technology Data Exchange (ETDEWEB)

    Kimmel, Nils

    2009-02-12

    Physics with X-rays spans from observing large scales in X-ray astronomy down to small scales in material structure analyses with synchrotron radiation. Both fields of research require imaging detectors featuring spectroscopic resolution for X-rays in an energy range of 0.1 keV to 20.0 keV. Originally driven by the need for an imaging spectrometer on ESA's X-ray astronomy satellite mission XMM-Newton, X-ray pnCCDs were developed at the semiconductor laboratory of the Max-Planck-Institute. The pnCCD is a pixel array detector made of silicon. It is sensitive over a wide band from near infrared- over optical- and UV-radiation up to X-rays. This thesis describes the dynamics of signal electrons from the moment after their generation until their collection in the potential minima of the pixel structure. Experimentally, a pinhole array was used to scan the pnCCD surface with high spatial resolution. Numerical simulations were used as a tool for the modeling of the electrical conditions inside the pnCCD. The results predicted by the simulations were compared with the measurements. Both, experiment and simulation, helped to establish a model for the signal charge dynamics in the energy range from 0.7 keV to 5.5 keV. More generally, the presented work has enhanced the understanding of the detector system on the basis of a physical model. The developed experimental and theoretical methods can be applied to any type of array detector which is based on the full depletion of a semiconductor substrate material. (orig.)

  12. Analysis of the charge collection process in solid state X-ray detectors

    International Nuclear Information System (INIS)

    Kimmel, Nils

    2009-01-01

    Physics with X-rays spans from observing large scales in X-ray astronomy down to small scales in material structure analyses with synchrotron radiation. Both fields of research require imaging detectors featuring spectroscopic resolution for X-rays in an energy range of 0.1 keV to 20.0 keV. Originally driven by the need for an imaging spectrometer on ESA's X-ray astronomy satellite mission XMM-Newton, X-ray pnCCDs were developed at the semiconductor laboratory of the Max-Planck-Institute. The pnCCD is a pixel array detector made of silicon. It is sensitive over a wide band from near infrared- over optical- and UV-radiation up to X-rays. This thesis describes the dynamics of signal electrons from the moment after their generation until their collection in the potential minima of the pixel structure. Experimentally, a pinhole array was used to scan the pnCCD surface with high spatial resolution. Numerical simulations were used as a tool for the modeling of the electrical conditions inside the pnCCD. The results predicted by the simulations were compared with the measurements. Both, experiment and simulation, helped to establish a model for the signal charge dynamics in the energy range from 0.7 keV to 5.5 keV. More generally, the presented work has enhanced the understanding of the detector system on the basis of a physical model. The developed experimental and theoretical methods can be applied to any type of array detector which is based on the full depletion of a semiconductor substrate material. (orig.)

  13. Homogeneity and fissure determination in uranium bars with solid state nuclear track detectors

    Energy Technology Data Exchange (ETDEWEB)

    Castillo, F. (Universidad Nacional Autonoma de Mexico, Mexico City. Facultad de Ciencias); Gamboa, I.; Espinosa, G.; Tapia, A. (Universidad Nacional Autonoma de Mexico, Mexico City. Inst. de Fisica); Somogyi, G. (Magyar Tudomanyos Akademia, Debrecen. Atommag Kutato Intezete)

    1984-01-01

    A simple and efficient method for determining fissure and concentration inhomogeneity in uranium bars is the alpha-radiographic technique. In our present work uranium bars made by ININ (Mexico) were studied by using CR-39 track detectors. The space inhomogeneity in track density was measured by an optical densitometer. The presence of fissure is determined by a microfiche reader. Such a study takes only few hours and does not require sophisticated instrumentation.

  14. Spectrophotometric determination of Tl carrier in 201Tl-TlCl injection

    International Nuclear Information System (INIS)

    Gong Quansheng; Jing Lie

    1997-01-01

    A simple and sensitive method for the spectrophotometric determination of carrier content (Thallium) in 201 Tl-TlCl injection is described. Thallium (I) is oxidised to Thallium (III) by aqueous bromine, then excess bromine is removed by adding sulfosalicylic acid. In buffer solution (NH 4 Cl-NH 4 OH) at pH 11.7 with the presence of emulsifier OP, thallium (III) and cadion form a complex having an absorption maximum at 469 nm with a molar absorptivity of 1.37 x 10 4 m 2 /mol. Beer's law is obeyed in the concentration range of 0-7 μg/5 mL. The effect of impurity elements in 201 Tl-TlCl injection is examined. It is an ideal method for the analysis of radioactive solution

  15. Study of method of efficiency transference using detectors NaI(Ti)

    International Nuclear Information System (INIS)

    Ramos, Thiago L.; Salgado, César M.

    2017-01-01

    The use of NaI (Tl) scintillation detectors for measurements implies the determination of the detection efficiency as a function of the energy of the incident photons. The efficiency curve can be obtained experimentally with the use of several mono-energy sources calibrated with emission energies covering the whole range of interest or using the Monte Carlo method. The Institute of Nuclear Engineering develops several methodologies using these detectors as they are robust, inexpensive and do not need cooling for their use. The assembly of an experimental arrangement is usually complex, since several factors influence the result affecting reproducibility in measurements, such as: parallelism between source and detector, alignment between source and detector, and accuracy of source-detector distance. In view of such difficulties, an automated positioning system was developed for the source-detector set controlled by a micro controller based on the ARDUINO language in order to guarantee the reproducibility in the experimental arrangements. In the initial phase of this study, a mathematical model was developed in the MCNP-X code using a NaI (Tl) detector. A theoretical validation using the Efficiency Transfer Method was performed at three different positions on the detector's axial axis (10.6 cm, 11.3 cm and 12.0 cm). This method is based on the ratio of effective solid angles. The experimental validation presented maximum relative errors of 7.74% for the position 11.3 cm

  16. Flow electrochemical biosensors based on enzymatic porous reactor and tubular detector of silver solid amalgam

    Czech Academy of Sciences Publication Activity Database

    Josypčuk, Bohdan; Barek, J.; Josypčuk, Oksana

    2013-01-01

    Roč. 778, MAY 2013 (2013), s. 24-30 ISSN 0003-2670 R&D Projects: GA ČR GAP206/11/1638 Institutional support: RVO:61388955 Keywords : flow analysis * amperometry * silver solid amalgam Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.517, year: 2013

  17. The past and future roles of solid state nuclear tracks detectors

    International Nuclear Information System (INIS)

    Fleischer, R.L.

    1976-01-01

    Nuclear tracks in solids can be revealed by a variety of techniques, the simplest and most widely used of which is that of preferential chemical attack. Particle track etching has been used in a diversity of fields, both scientific and applied. This report first reviews the applications and then hazards some predictions for the future. (orig.) [de

  18. Solid State nuclear track detector - [Part] III : applications in science and technology

    International Nuclear Information System (INIS)

    Lal, Nand

    1992-01-01

    The present article describes the applications of solid state nuclear track detection techniques in different branches of science (e.g. life sciences, nuclear physics, cosmic ray and solar physics, earth sciences, teaching laboratories) and technology with selected examples from voluminous literature available on the subject. (author). 28 refs., 6 figs., 3 tabs

  19. Development of an area monitor for neutrons using solid state nuclear track detector; Desenvolvimento de um monitor de area para neutrons utilizando detector solido de tracos nucleares

    Energy Technology Data Exchange (ETDEWEB)

    Zahn, G.S.

    1994-12-31

    An area monitor for neutrons composed of the solid state nuclear track detector (SSNTD) Makrofol DE, together with a (n,{alpha}) converter, in the center of a 25 cm diameter polyethylene sphere, is developed. The optimal electrochemical etching conditions for the detection of thermal neutrons by the Makrofol DE using the BN converter are studied, leading to the choice of 55 min, at 30{sup 0} C, under a 44,2 kV.cm{sup -1} electric field with oscillation frequency of 2,0 khz. The response of this system to thermal neutrons, in the optimal conditions, is of 2,76(10)x 10{sup -3} tr/n. Changing from the BN converter to a 2,73(3)g compressed boric acid tablet this value lowers to 3,88(17)x 10{sup -4} tr/n. The performance of the whole monitor in the detection of fast neutrons is examined using the BN converter and neutrons from a {sup 241} Am Be source, with a response of 4,4(2)x 10{sup 3} tr.mSv{sup -1}.cm{sup -2} and operational limits between 7(3){mu}Sv and 5,6(2)mSv. The result of the monitoring of the control room of the IPEN Cyclotron accelerator are also presented as a final test for the viability of the practical use of the monitor. (author). 34 refs, 15 figs, 6 tabs, 1 app.

  20. Vortex states of Tl2Ba2CuO6+δ studied via 205Tl NMR at 2 tesla

    International Nuclear Information System (INIS)

    Itoh, Yutaka; Michioka, Chishiro; Yoshimura, Kazuyoshi; Hayashi, Akihiko; Ueda, Yutaka

    2005-01-01

    We report a 205 Tl NMR study of vortex states in an aligned polycrystalline sample of an overdoped high-T c superconductor, Tl 2 Ba 2 CuO 6+δ (Tc - 85 K), at a magnetic field of 2 T along the c axis. We observed an imperfect vortex lattice, so-called Bragg glass, at T=5 K, the coexistence of vortex solid and vortex liquid between 10 and 60 K, and vortex melting between 65 and 85 K. No evidence for local antiferromagnetic ordering at vortex cores was found for our sample. (author)

  1. A new luminescence detection and stimulation head for the Risø TL/OSL reader

    International Nuclear Information System (INIS)

    Lapp, T.; Kook, M.; Murray, A.S.; Thomsen, K.J.; Buylaert, J.-P.; Jain, M.

    2015-01-01

    A new automated Detection And Stimulation Head (DASH) has been developed for the Risø TL/OSL luminescence reader to provide easy access to new technologies, new signals and new measurement methods. The automated DASH includes a filter changer and a detector changer that makes it possible to change stimulation filters (4 × 4 filter combinations possible) and detectors (3 detectors possible) as part of a measurements sequence. The new automated DASH with dedicated driver electronics does not affect the use of other attachments, and can be retrospectively fitted to existing Risø TL/OSL readers. - Highlights: • A new detection and stimulation head for the Risø TL/OSL reader is described. • An example of the use of the filter changer is presented. • The power and spatial uniformity of blue, green and IR stimulation are characterised. • The potential of an EMCCD camera detector is described.

  2. A method for the measurement of fission rates in fast neutron fields using solid state track detectors

    International Nuclear Information System (INIS)

    Hansen, W.; Vogel, W.

    1984-04-01

    Solid state track detectors (SSTDs) are increasingly used for the registration of radiation in different fields of nuclear physics. Because of their small sizes and masses and the absence of any electronics during exposure SSTDs do not cause distortions in the system to be investigated and are useful for measurements at such places being difficult of access. The elaboration of a method is described for fission rate measurements in fast neutron fields applying SSTDs and different fissionable isotopes which were electrodeposited on stainless steel backings. Experiences of the electrodeposition and results of quality checks are presented. The evaluation of the etched tracks is performed with spark counter technique. The dependence of the counting result on essential influence parameters is discussed. (author)

  3. Observation of superheavy primary cosmic ray nuclei with solid state track detectors and x-ray films

    International Nuclear Information System (INIS)

    Doke, Tadayoshi; Hayashi, Takayoshi; Ito, Kensai; Yanagimachi, Tomoki; Kobayashi, Shigeru.

    1977-01-01

    The measurements of energy spectra and the nuclear charge distribution of superheavy nuclei heavier than iron in primary cosmic ray can provide information on the origin, propagation and life time of the cosmic ray. Since incident particles are in the region of relativistic velocity (the low energy cosmic ray below the cutoff energy is forbidden from entering), the charges of cosmic ray nuclei can be determined without knowing the energy of particles. The balloon-borne solid state track detector and plastic and X-ray films were employed for the detection of superheavy cosmic ray, and the five events were detected with the cellulose nitrate film. The flux of superheavy nuclei is predicted from the present analysis. (Yoshimori, M.)

  4. Damage flux analysis. Solid state detector and Monte-Carlo calculation

    International Nuclear Information System (INIS)

    Genthon, J.P.; Nimal, J.C.; Vergnaud, T.

    1975-09-01

    The change of resistivity induced by radiation in materials is particularly suitable for the measurement of equivalent damage fluxes, when it is used at low fluence for calibration of more classical activation reactions used at high fluences. A graphite and a tungsten detector are briefly described and results obtained in a good number of European reactors are given. The polykinetic three dimensional Monte-Carlo code Tripoli is used for calculation of damage fluxes. Comparison with above measurements shows a good agreement and confirms the use of the EURATOM damaging function for graphite [fr

  5. Some characteristics of the CR-39 solid state nuclear - Track Detector for register of protons and low energy alpha particles

    International Nuclear Information System (INIS)

    Fonseca, E.S. da.

    1983-01-01

    Experimental results related to registration properties of the CR-39 Solid State Nuclear Track Detector for charged particles are presented and discussed. The existence of an inverse proportion between the induction time and the temperature as well as normal concentration of solutions, is showed by the study of CR-39 chemical etching characteristics in NaOH and KOH solutions, comprising varied concentration and temperature. The bulk-etch rate and activation energy of the process were obtained. The critical energy and critical energy-loss rate of CR-39 track-detectors for registration of protons were experimentally determined. Samples were exposed to 24 Mev proton beams in the IEN/CNEN Cyclotron (CV-28), using scattering chamber with a tantalum thin target and aluminium absorbers in contact with the samples, in order to provide the required fluctuation in the scattered beam energy. From the mean track-diameter plotted against incident proton energy the critical energy was obtained. From the calculated energy-loss rate vs. energy curve, the critical energy loss rate were evaluated. The CR-39 response for low energy alpha particles (E = 7h) under the conditions of 6.25 N NaOH at 70 0 C. It is shown that successive chemical etchings do not produce the same track geometry as obtained by means of a continous revelation with the same total etching time. (Author) [pt

  6. Evaluation of Origin Ensemble algorithm for image reconstruction for pixelated solid-state detectors with large number of channels

    Science.gov (United States)

    Kolstein, M.; De Lorenzo, G.; Mikhaylova, E.; Chmeissani, M.; Ariño, G.; Calderón, Y.; Ozsahin, I.; Uzun, D.

    2013-04-01

    The Voxel Imaging PET (VIP) Pathfinder project intends to show the advantages of using pixelated solid-state technology for nuclear medicine applications. It proposes designs for Positron Emission Tomography (PET), Positron Emission Mammography (PEM) and Compton gamma camera detectors with a large number of signal channels (of the order of 106). For PET scanners, conventional algorithms like Filtered Back-Projection (FBP) and Ordered Subset Expectation Maximization (OSEM) are straightforward to use and give good results. However, FBP presents difficulties for detectors with limited angular coverage like PEM and Compton gamma cameras, whereas OSEM has an impractically large time and memory consumption for a Compton gamma camera with a large number of channels. In this article, the Origin Ensemble (OE) algorithm is evaluated as an alternative algorithm for image reconstruction. Monte Carlo simulations of the PET design are used to compare the performance of OE, FBP and OSEM in terms of the bias, variance and average mean squared error (MSE) image quality metrics. For the PEM and Compton camera designs, results obtained with OE are presented.

  7. Weightfield2: A fast simulator for silicon and diamond solid state detector

    Energy Technology Data Exchange (ETDEWEB)

    Cenna, Francesca, E-mail: cenna@to.infn.it [INFN Torino, Via Pietro Giuria 1, Torino (Italy); Cartiglia, N. [INFN Torino, Via Pietro Giuria 1, Torino (Italy); Friedl, M.; Kolbinger, B. [HEPHY Vienna (Austria); Sadrozinski, H.F.-W.; Seiden, A.; Zatserklyaniy, Andriy; Zatserklyaniy, Anton [University of California, Santa Cruz (United States)

    2015-10-01

    We have developed a fast simulation program to study the performance of silicon and diamond detectors, Weightfield2. The program uses GEANT4 libraries to simulate the energy released by an incoming particle in silicon (or diamond), and Ramo's theorem to generate the induced signal current. A graphical interface allows the user to configure many input parameters such as the incident particle, sensor geometry, presence and value of internal gain, doping of silicon sensor and its operating conditions, the values of an external magnetic field, ambient temperature and thermal diffusion. A simplified electronics simulator is also implemented to include the response of an oscilloscope and front-end electronics. The program has been validated by comparing its predictions for minimum ionizing and α particles with measured signals and TCAD simulations, finding very good agreement in both cases.

  8. Numerical Simulations of Pillar Structured Solid State Thermal Neutron Detector Efficiency and Gamma Discrimination

    Energy Technology Data Exchange (ETDEWEB)

    Conway, A; Wang, T; Deo, N; Cheung, C; Nikolic, R

    2008-06-24

    This work reports numerical simulations of a novel three-dimensionally integrated, {sup 10}boron ({sup 10}B) and silicon p+, intrinsic, n+ (PIN) diode micropillar array for thermal neutron detection. The inter-digitated device structure has a high probability of interaction between the Si PIN pillars and the charged particles (alpha and {sup 7}Li) created from the neutron - {sup 10}B reaction. In this work, the effect of both the 3-D geometry (including pillar diameter, separation and height) and energy loss mechanisms are investigated via simulations to predict the neutron detection efficiency and gamma discrimination of this structure. The simulation results are demonstrated to compare well with the measurement results. This indicates that upon scaling the pillar height, a high efficiency thermal neutron detector is possible.

  9. Determination of absolute detection efficiencies for detectors of interest in homeland security

    International Nuclear Information System (INIS)

    Ayaz-Maierhafer, Birsen; DeVol, Timothy A.

    2007-01-01

    The absolute total and absolute peak detection efficiencies of gamma ray detector materials NaI:Tl, CdZnTe, HPGe, HPXe, LaBr 3 :Ce and LaCl 3 :Ce were simulated and compared to that of polyvinyltoluene (PVT). The dimensions of the PVT detector were 188.82 cmx60.96 cmx5.08 cm, which is a typical size for a single-panel portal monitor. The absolute total and peak detection efficiencies for these detector materials for the point, line and spherical source geometries of 60 Co (1332 keV), 137 Cs (662 keV) and 241 Am (59.5 keV) were simulated at various source-to-detector distances using the Monte Carlo N-Particle software (MCNP5-V1.30). The comparison of the absolute total detection efficiencies for a point, line and spherical source geometry of 60 Co and 137 Cs at different source-to-detector distance showed that the absolute detection efficiency for PVT is higher relative to the other detectors of typical dimensions for that material. However, the absolute peak detection efficiency of some of these detectors are higher relative to PVT, for example the absolute peak detection efficiency of NaI:Tl (7.62 cm diameterx7.62 cm long), HPGe (7.62 cm diameterx7.62 cm long), HPXe (11.43 cm diameterx60.96 cm long), and LaCl 3 :Ce (5.08 cm diameterx5.08 cm long) are all greater than that of a 188.82 cmx60.96 cmx5.08 cm PVT detector for 60 Co and 137 Cs for all geometries studied. The absolute total and absolute peak detection efficiencies of a right circular cylinder of NaI:Tl with various diameters and thicknesses were determined for a point source. The effect of changing the solid angle on the NaI:Tl detectors showed that with increasing solid angle and detector thickness, the absolute efficiency increases. This work establishes a common basis for differentiating detector materials for passive portal monitoring of gamma ray radiation

  10. Radiation Hardness Study of CsI(Tl) Crystals for Belle II Calorimeter

    CERN Document Server

    Matvienko, D V; Sedov, E V; Shwartz, B A

    2017-01-01

    The Belle II calorimeter (at least, its barrel part) consists of CsI(Tl) scintillation crystals which have been used at the Belle experiment. We perform the radiation hardness study of some typical Belle crystals and conclude their light output reductions are acceptable for Belle II experiment where the absorption dose can reach 10 krad during the detector operation. CsI(Tl) crystals have high stablity and low maintenance cost and are considered as possible option for the calorimeter of the future Super-Charm-Tau factory (SCT) in Novosibirsk. Our study demonstrates sufficiently high radiation hardness of CsI(Tl) crystals for SCT conditions.

  11. Basic performance and stability of a CdTe solid-state detector panel.

    Science.gov (United States)

    Tsuchiya, Katsutoshi; Takahashi, Isao; Kawaguchi, Tsuneaki; Yokoi, Kazuma; Morimoto, Yuuichi; Ishitsu, Takafumi; Suzuki, Atsurou; Ueno, Yuuichirou; Kobashi, Keiji

    2010-05-01

    We have developed a prototype gamma camera system (R1-M) using a cadmium telluride (CdTe) detector panel and evaluated the basic performance and the spectral stability. The CdTe panel consists of 5-mm-thick crystals. The field of view is 134 x 268 mm comprising 18,432 pixels with a pixel pitch of 1.4 mm. Replaceable small CdTe modules are mounted on to the circuit board by dedicated zero insertion force connectors. To make the readout circuit compact, the matrix read out is processed by dedicated ASICs. The panel is equipped with a cold-air cooling system. The temperature and humidity in the panel were kept at 20 degrees C and below 70% relative humidity. CdTe polarization was suppressed by the bias refresh technique to stabilize the detector. We also produced three dedicated square pixel-matched collimators: LEGP (20 mm-thick), LEHR (27 mm-thick), and LEUHR (35 mm-thick). We evaluated their basic performance (energy resolution, system resolution, and sensitivity) and the spectral stability in terms of short-term (several hours of continuous acquisition) and long-term (infrequent measurements over more than a year) activity. The intrinsic energy resolution (FWHM) acquired with Tc-99m (140.5 keV) was 6.6%. The spatial resolutions (FWHM at a distance of 100 mm) with LEGP, LEHR, and LEUHR collimators were 5.7, 4.9, and 4.2 mm, and the sensitivities were 71, 39, and 23 cps/MBq, respectively. The energy peak position and the intrinsic energy resolution after several hours of operation were nearly the same as the values a few minutes after the system was powered on; the variation of the peak position was <0.2%, and that of the resolution was about 0.3%. Infrequent measurements conducted over a year showed that the variations of the energy peak position and the intrinsic energy resolution of the system were at a similar level to those described above. The basic performance of the CdTe-gamma camera system was evaluated, and its stability was verified. It was shown that the

  12. Amorphous silicon solid-state detectors and their future application in medical X-ray imaging

    International Nuclear Information System (INIS)

    Spahn, M.; Alexander, J.; Gmeinwieser, J.

    1997-01-01

    With the goal of testing the new technology under clinical conditions, in a cooperation between Thomson Tubes Electroniques (Moirans, France) and the Siemens Medical Engineering Group the first a-Si detector prototypes have been developed. On the basis of these activities and together with another European partner the independent company Trixell S.A.S. was established. A technological prototype with a matrix size of 1k x 1k and a pixel size of 200 μm [4] was installed in 1995 in the Cardiology Department of the University Hospital in Freiburg (Germany). The system was designed to operate at 12.5 frames per seconds with full geometrical resolution and 25 frames per second with half the full geometrical resolution. In the clinical environment, both the high contrast and the good image impression, especially at cinematographic doses, was acknowledged. In this early stage of development, however, the signal-to-noise ratio was somewhat inferior to that of I.I.-TV systems at fluoroscopic doses. (orig.)

  13. Tl Cuprate Superconductors Studied by XPS

    Energy Technology Data Exchange (ETDEWEB)

    Vasquez, R. P. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109-8099 (United States); Siegal, M. P. [Sandia National Laboratories, Albuquerque, NM 87185-1421 (United States); Overmyer, D. L. [Sandia National Laboratories, Albuquerque, NM 87185-1421 (United States); Ren, Z. F. [Department of Chemistry, State University of New York, Buffalo, NY 14260-3000 (United States); Lao, J. Y. [Department of Chemistry, State University of New York, Buffalo, NY 14260-3000 (United States); Wang, J. H. [Department of Chemistry, State University of New York, Buffalo, NY 14260-3000 (United States)

    1999-07-01

    XPS measurements on epitaxial thin films of the Tl cuprate superconductors Tl2Ba2CaCu2O8, Tl2Ba2Ca2Cu3O10, and Tl0.78Bi0.22Ba0.4Sr1.6Ca2Cu3O9-{delta} are presented. These data, together with previous measurements in this lab on Tl2Ba2CuO6-{delta} and TlBa2CaCu2O7-{delta}, comprise a comprehensive data set for comparison of Tl cuprates in which the number of Tl-O and Cu-O layers, and hence the chemical and electronic properties, vary. (c) 2000 American Vacuum Society.

  14. Tl Cuprate Superconductors Studied by XPS

    International Nuclear Information System (INIS)

    Vasquez, R. P.; Siegal, M. P.; Overmyer, D. L.; Ren, Z. F.; Lao, J. Y.; Wang, J. H.

    1999-01-01

    XPS measurements on epitaxial thin films of the Tl cuprate superconductors Tl2Ba2CaCu2O8, Tl2Ba2Ca2Cu3O10, and Tl0.78Bi0.22Ba0.4Sr1.6Ca2Cu3O9-δ are presented. These data, together with previous measurements in this lab on Tl2Ba2CuO6-δ and TlBa2CaCu2O7-δ, comprise a comprehensive data set for comparison of Tl cuprates in which the number of Tl-O and Cu-O layers, and hence the chemical and electronic properties, vary. (c) 2000 American Vacuum Society

  15. Some characteristics of the CR-39 solid state nuclear-track detector for protons and low energy alpha particles

    International Nuclear Information System (INIS)

    Fonseca, E.S. da.

    1983-01-01

    Experimental results related to certain registration properties of the CR-39 solid state nuclear-track detector for charged particles are presented and discussed. The determination of the CR-39 chemical etching in NaOH and KOH solutions, comprising concentration (2-10N) and temperature effects (50-90 0 C), showed the existence of an inverse proportion between the induction time and the temperature as well as the normal concentration of the solutions. The critical energy and the critical energy-loss rate of CR-39 track detectors for registration of protons were experimentally determined. A number of samples was exposed to 24MeV proton beams in the IEN-CNEN Cyclotron (CV-28), using a scattering chamber with a tantalum thin target and aluminium absorbers in contact with the samples in order to provide the required fluctuation in the scattered beam energy. From the mean track-diameter plotted against incident proton energy for 16h and 24h chemical etching (6.25 NaOH, 70 0 C), and considering 1.5 μm as the minimum observable track-diameter, the values (21.0 + - 1.5) MeV and (22.5 + - 1.5) MeV were deduced, respectively, for the critical energy. From the calculated energy-loss rate versus energy curve, the critical energy-loss rate was evaluated as 24 + - 2 MeV.cm 2 /g. Finally, the CR-39 response for low energy alpha particles (E [pt

  16. A review of the developments of radioxenon detectors for nuclear explosion monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Sivels, Ciara B.; McIntyre, Justin I.; Bowyer, Theodore W.; Kalinowski, Martin B.; Pozzi, Sara A.

    2017-09-27

    Developments in radioxenon monitoring since the implementation of the International Monitoring System are reviewed with emphasis on the most current technologies to improve detector sensitivity and resolution. The nuclear detectors reviewed include combinations of plastic and NaI(Tl) detectors, high purity germanium detectors, silicon detectors, and phoswich detectors. The minimum detectable activity and calibration methods for the various detectors are also discussed.

  17. Optical CT imaging of solid radiochromic dosimeters in mismatched refractive index solutions using a scanning laser and large area detector.

    Science.gov (United States)

    Dekker, Kurtis H; Battista, Jerry J; Jordan, Kevin J

    2016-08-01

    The practical use of the PRESAGE® solid plastic dosimeter is limited by the inconvenience of immersing it in high-viscosity oils to achieve refractive index matching for optical computed tomography (CT) scanning. The oils are slow to mix and difficult to clean from surfaces, and the dosimeter rotation can generate dynamic Schlieren inhomogeneity patterns in the reference liquid, limiting the rotational and overall scan speed. Therefore, it would be beneficial if lower-viscosity, water-based solutions with slightly unmatched refractive index could be used instead. The purpose of this work is to demonstrate the feasibility of allowing mismatched conditions when using a scanning laser system with a large acceptance angle detector. A fiducial-based ray path measurement technique is combined with an iterative CT reconstruction algorithm to reconstruct images. A water based surrounding liquid with a low viscosity was selected for imaging PRESAGE® solid dosimeters. Liquid selection was optimized to achieve as high a refractive index as possible while avoiding rotation-induced Schlieren effects. This led to a refractive index mismatch of 6% between liquid and dosimeters. Optical CT scans were performed with a fan-beam scanning-laser optical CT system with a large area detector to capture most of the refracted rays. A fiducial marker placed on the wall of a cylindrical sample occludes a given light ray twice. With knowledge of the rotation angle and the radius of the cylindrical object, the actual internal path of each ray through the dosimeter can be calculated. Scans were performed with 1024 projections of 512 data samples each, and rays were rebinned to form 512 parallel-beam projections. Reconstructions were performed on a 512 × 512 grid using 100 iterations of the SIRT iterative CT algorithm. Proof of concept was demonstrated with a uniformly attenuating solution phantom. PRESAGE® dosimeters (11 cm diameter) were irradiated with Cobalt-60 irradiator to achieve

  18. Emergency Department Ultrasound Is not a Sensitive Detector of Solid Organ Injury

    Directory of Open Access Journals (Sweden)

    Kendall, John L

    2009-02-01

    Full Text Available Objective: To estimate the sensitivity and specificity of emergency department (ED ultrasound for the detection of solid organ injury following blunt abdominal trauma.Methods: A prospective cohort study performed in the ED of an urban Level I trauma center on patients who sustained blunt abdominal trauma. Following initial standard trauma evaluation, patients underwent a secondary ultrasound examination performed specifically to identify injury to the liver or spleen, followed by computed tomography (CT scan of the abdomen. Ultrasound examinations were performed by emergency medicine residents or attending physicians experienced in the use of ultrasound for detecting hemoperitoneum. Ultrasonographers prospectively determined the presence or absence of liver or spleen injury. CT findings were used as the criterion standard to evaluate the ultrasound results.Results: From July 1998 through June 1999, 152 patients underwent secondary ultrasound examination and CT. Of the 152 patients, nine (6% had liver injuries and 10 (7% had spleen injuries. Ultrasound correctly detected only one of the liver injuries for a sensitivity of 11% (95% CI: 0%-48% and a specificity of 98% (95% CI: 94%-100%. Ultrasound correctly detected eight spleen injuries for a sensitivity of 80% (95% CI: 44%-98% and a specificity of 99% (95% CI: 95%-100%.Conclusion: Emergency ultrasound is not sensitive or specific for detecting liver or spleen injuries following blunt abdominal trauma.[WestJEM. 2009;10:1-5.

  19. Results from the crystal ball detector at SPEAR

    International Nuclear Information System (INIS)

    Bloom, E.D.

    1979-11-01

    The Crystal Ball detector is a device particularly suited to the measurement of photons with energies lower than 1 GeV. The detector has as its principal component a 16 radiation length thick, highly segmented shell of NaI(Tl) surrounding cylindrical, proportional, and magnetostrictive spark chambers. The main Ball and various elements of the central chambers cover 94% of 4π sr. Segmented endcap NaI(Tl) detectors of 20 radiation lengths behind magneto strictive spark chambers supplement the main Ball. The Ball and endcaps close the solid angle for charged particle and photon detection to 98% of 4π sr. In addition, detectors of interspersed iron and proportional tubes provide for μ-π separation over 15% of 4π sr, about theta/sub CM/ = 90 0 . In this report preliminary results are presented from the data obtained. In particular, QED at E/sub CM/ = 6.5 GeV, R/sub hadron/ and related inclusive distributions, eta branching fractions at J/psi and psi'', and a detailed study of the psionium system are discussed

  20. Determination of the activity concentration of a 238 Pu solution by the defined solid angle method utilizing a novel dual diaphragm-detector assembly.

    Science.gov (United States)

    Aguiar, Julio C; Galiano, Eduardo; Arenillas, Pablo

    2005-08-01

    The activity concentration of a (238)Pu solution was measured by the determined solid angle method employing a novel dual diaphragm-detector assembly, which has been previously described. Due to the special requirements of the detector, a new type of source holder was developed, which consisted of sandwiching the radioisotope between two organic films called VYNS. It was experimentally demonstrated that the VYNS films do not absorb alpha particles, but reduce their energy by an average of 22 keV.A mean activity concentration for (238)Pu of 359.10+/-0.8 kBq/g was measured.

  1. Determination of the activity concentration of a {sup 238}Pu solution by the defined solid angle method utilizing a novel dual diaphragm-detector assembly

    Energy Technology Data Exchange (ETDEWEB)

    Aguiar, Julio C. [Departamento de Postgrado, Universidad Tecnologica Nacional, Buenos Aires (Argentina); Galiano, Eduardo [Departament of Physics, Laurentian University, Sudbury, Ont. P3E 2C6 (Canada)]. E-mail: egalianoriveros@laurentian.ca; Arenillas, Pablo [Comision Nacional de Energia Atomica, CAE, Laboratorio de Metrologia de Radioisotopos, Buenos Aires (Argentina)

    2005-08-01

    The activity concentration of a {sup 238}Pu solution was measured by the determined solid angle method employing a novel dual diaphragm-detector assembly, which has been previously described. Due to the special requirements of the detector, a new type of source holder was developed, which consisted of sandwiching the radioisotope between two organic films called VYNS. It was experimentally demonstrated that the VYNS films do not absorb {alpha} particles, but reduce their energy by an average of 22keV.A mean activity concentration for {sup 238}Pu of 359.10+/-0.8kBq/g was measured.

  2. Determination of the activity concentration of a 238Pu solution by the defined solid angle method utilizing a novel dual diaphragm-detector assembly

    International Nuclear Information System (INIS)

    Aguiar, Julio C.; Galiano, Eduardo; Arenillas, Pablo

    2005-01-01

    The activity concentration of a 238 Pu solution was measured by the determined solid angle method employing a novel dual diaphragm-detector assembly, which has been previously described. Due to the special requirements of the detector, a new type of source holder was developed, which consisted of sandwiching the radioisotope between two organic films called VYNS. It was experimentally demonstrated that the VYNS films do not absorb α particles, but reduce their energy by an average of 22keV.A mean activity concentration for 238 Pu of 359.10+/-0.8kBq/g was measured

  3. Theories of TL systems: Failures, successes, conflicts, trends: Insights into possible future materials and techniques

    International Nuclear Information System (INIS)

    Horowitz, Y. S.; Belaish, Y.; Oster, L.

    2006-01-01

    In this paper some of the many theoretical models dealing with characteristics of TL materials are discussed. Special attention is given to some of the models dealing with the effects of ionisation density, that is Modified Track Structure Theory (MTST) and Micro-dosimetric Track Structure Theory (MTT) for the calculation of Heavy Charged Particle relative TL efficiencies, as well as solid-state models based on conduction band/valence band theory. Failures, successes, conflicts and trends are highlighted as well as a peek into future avenues of research for dosimetric TL materials. (authors)

  4. Measurement of gross alpha - activity in some thermal water sources in Yugoslavia by SSNTDs. [Solid state nuclear track detectors

    Energy Technology Data Exchange (ETDEWEB)

    Benderac, R.; Ristic, D. (Inst. of Security, Belgrade (Yugoslavia)); Antanasijevic, R.; Vukovic, J. (Belgrade Univ. (Yugoslavia))

    1991-01-01

    The possible application of the CN-BDH (type 1) nitrocellulose detector synthesized in laboratory conditions, and also the CR-39 detector, to the measurement of the gross alpha-activity of geothermal and mineral water has been investigated. (author).

  5. Tl response of KMgF{sub 3}: Lu + PTFE at ultraviolet radiation; Respuesta Tl de KMgF{sub 3}: Lu + PTFE a radiacion ultravioleta

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, P R [Instituto Nacional de Investigaciones Nucleares, A.P. 18 -1027, 11801 Mexico D.F. (Mexico); Alarcon, N G [Facultad de Quimica, Universidad Autonoma del Estado de Mexico. Paseo Tollocan, Esq. con Jesus Carranza, 50180 Toluca, Estado de Mexico (Mexico); Furetta, C; Azorin, J [Universidad Autonoma Metropolitana- Iztapalapa, San Rafael Atlixco 186, 09340 Mexico. D.F. (Mexico)

    2003-07-01

    Ionizing radiation has different types of interaction with a crystalline solid. However, only few effects are interesting to optimize some thermoluminescent (Tl) properties of certain Tl materials. This paper presents results obtained by irradiating KMgF{sub 3}: Lu + Ptfe Tl dosimeters with ultraviolet (UV) radiation previously exposed to gamma radiation. These results showed that those dosimeters not exposed previously to gamma radiation did not presented any Tl signal. Meanwhile, those previously submitted to gamma irradiation showed that their sensitivity was increased as the gamma dose increased. The glow curve of sensitized KMgF{sub 3}: Lu + Ptfe exposed to UV radiation, presented the dosimetric pea at 212 C. This makes this material to be promissory for measuring UV radiation. (Author)

  6. Investigations of portable cadmium telluride (CdTe(Cl)) detectors for clinical studies with radioactive indicators

    International Nuclear Information System (INIS)

    Bojsen, J.

    1985-01-01

    The combination of small, portable γ-radiation-sensitive Cadmium Telluride (CdTE(Cl)) crystal detectors and portable solid state data storage memories makes it feasible to extend the measuring period in a number of clinical investigations based on the use of various radioisotopes and external detection. Blood sampling can be avoided in some cases. Continuous ambulatory monitoring of relevant physiological parameters is practicable, e.g. kidney function (GFR), left ventricular ejection fraction, subcutaneous blood flow, muscle blood flow and insulin absorption in diabetic patients. In the present methodological study the applicability of the 133-Xe washout technique to subcutaneous (s.c.) adipose tissue blood flow (SBF) has been investigated and adapted to the use of CdTe(Cl) detectors attached to the skin surface for the measurement of local 133-Xe-disappearance rate constants (k). Physical characterization of CdTe(Cl) detectors as γ-sensitive devices has been performed, and adequate counting sensitivities were found without detector energy-resolution properties. The CdTe(Cl) detectors are therefore suitable for single indicator studies. The measuring geometry of CdTe(Cl) detectors was studied and compared with that of stationary Sodium Iodide (NaI(Tl)) detectors in both phantom and in vivo investigations. The spatial properties of CdTe(Cl) detectors could to some extent be adjusted by pulse height discrimination and lead collimation. When long-term measurements were complicated by for instance physical activity of the patients, the small CdTe(Cl) detectors in general showed equal or better performance than the heavy and voluminous NaI(Tl) detectors. The free movement of the ambulatory patient and the avoidance of cable connections to stationary data-collecting systems gave improved possibilities for measurements of the relevant parameters. From this point of view, portable CdTe(Cl) detectors must be considered an important advance for radioactivity studies in

  7. Characterisation of a Personal TL Photon Dosemeter Based on Two LiF(Mg,Cu,P) Detectors in Terms of Hp(0.07,alpha) and Hp(10,alpha)

    International Nuclear Information System (INIS)

    Fantuzzi, E.; Monteventi, F.; Sermenghi, I.; Uleri, G.

    1999-01-01

    A study was undertaken to evaluate the response of the ENEA Photon Personal Dosemeter, slightly modified in design, in terms of H p (0.07, α) and H p (10, α). A filtration of 20 and 270 mg.cm -2 respectively for the two LiF(Mg,Cu,P) detectors employed was adopted according to a preliminary analytical simulation. The new dosemeter can measure both H p (0.07, α) with a maximum uncertainty of ±4% in the range from 10 to 200 keV and H p (10, α) with a maximum uncertainty of ±15% in the range from 10 keV to 1.25 MeV, using the detector responses together with a correction function with respect to their ratio. Moreover, tests were performed to evaluate the dosemeter angular response (0 deg., 20 deg., 40 deg., and 60 deg.) obtaining good results according to international recommendations. All irradiation tests were performed at SSL of ENEA Institute for Radiation Protection in Bologna using the ISO water phantom (30 x 30 x 15 cm 3 ) and standard ISO filtered X ray beams as well as 137 Cs and 60 Co sources. This work represents a preliminary type test of the ENEA photon personal dosemeter and allows its introduction in routine dosimetry practice in accordance with the ICRU reference quantities. (author)

  8. Calibration with MCNP of NaI detector for the determination of natural radioactivity levels in the field.

    Science.gov (United States)

    Cinelli, Giorgia; Tositti, Laura; Mostacci, Domiziano; Baré, Jonathan

    2016-05-01

    In view of assessing natural radioactivity with on-site quantitative gamma spectrometry, efficiency calibration of NaI(Tl) detectors is investigated. A calibration based on Monte Carlo simulation of detector response is proposed, to render reliable quantitative analysis practicable in field campaigns. The method is developed with reference to contact geometry, in which measurements are taken placing the NaI(Tl) probe directly against the solid source to be analyzed. The Monte Carlo code used for the simulations was MCNP. Experimental verification of the calibration goodness is obtained by comparison with appropriate standards, as reported. On-site measurements yield a quick quantitative assessment of natural radioactivity levels present ((40)K, (238)U and (232)Th). On-site gamma spectrometry can prove particularly useful insofar as it provides information on materials from which samples cannot be taken. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  9. Development of a scintillator detector set with counter and data acquisition for flow measurements

    CERN Document Server

    Costa, F E D

    2002-01-01

    A portable counter with data acquisition system for flow measurements was developed, using the pulse velocity technique. This consists in determining the tracer transit time mixed homogeneously to the liquid or gas pipelines. The counter comprises: (a) two CsI(Tl) crystals solid state detectors, associated with Si PIN photodiodes, with compatible sensitivity to the injected radiotracers activities; (b) amplification units; (c) analogue-to-digital interface, which processes and displays the detectors counting separately and in real time, but in a same temporal axis, via a computer screen and (d) 30-m coaxial cables for signals transmission from each detector to the processing unit. Experiments were carried out for the detector and associated electronic characterizations. The equipment showed to be suitable for flow measurements in an industrial plant, in the real situation.

  10. Development of surgical gamma probes with TlBr semiconductors and CsI(Tl) scintillators crystals

    International Nuclear Information System (INIS)

    Costa, Fabio Eduardo da

    2006-01-01

    Radio guided surgery, using probes with radiation detectors, has been prominence in the medical area in the last decade. This technique consists in injecting a radioactive substance to concentrate in tumour and assist the localization during the surgical procedure. The radio guided surgeries allowing the identification of lymph node has revolutioned the behavior of tumour in initial stadium when are being spread by lymphatic way. The conditions imposed to the surgery due the proximity between some lymph nodes, demands of the probes, a small diameters and capacity of individual identification of these lymph nodes radiolabelled by a specific tracer. The international market supplies these probes with CdTe semiconductors and scintillators, but there is some time lack a promptly technical assistance in the Brazilian market. This work developed probes with national technology, using CsI(Tl) scintillators crystals and, in substitution to CdTe crystals semiconductors, the TlBr crystal, that is a new semiconductor detector in a world-wide development, with advantages in relation to the CdTe. Both crystals have been grown in IPEN. All the necessary electronics, specially, the preamplifier, that was also a restrictive factor for development of these types of probe in the country, have been developed with components found in the national market. Systematic measures of spatial resolution, spatial selectivity, maximum sensitivity and quality of the shielding have been carried the probes development. The results have shown that the probes, one with the CsI(Tl) crystal and another with TlBr semiconductor presented the requested performance in the international literature for radio guided probes. (author)

  11. Optical CT imaging of solid radiochromic dosimeters in mismatched refractive index solutions using a scanning laser and large area detector

    Energy Technology Data Exchange (ETDEWEB)

    Dekker, Kurtis H., E-mail: kdekker2@uwo.ca [Department of Medical Biophysics, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Ontario N6A 5C1 (Canada); Battista, Jerry J.; Jordan, Kevin J. [Departments of Medical Biophysics and Oncology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Ontario N6A 5C1, Canada and Department of Physics and Engineering, London Regional Cancer Program, London Health Sciences Centre, 790 Commissioners Road East, London, Ontario N6A 4L6 (Canada)

    2016-08-15

    Purpose: The practical use of the PRESAGE® solid plastic dosimeter is limited by the inconvenience of immersing it in high-viscosity oils to achieve refractive index matching for optical computed tomography (CT) scanning. The oils are slow to mix and difficult to clean from surfaces, and the dosimeter rotation can generate dynamic Schlieren inhomogeneity patterns in the reference liquid, limiting the rotational and overall scan speed. Therefore, it would be beneficial if lower-viscosity, water-based solutions with slightly unmatched refractive index could be used instead. The purpose of this work is to demonstrate the feasibility of allowing mismatched conditions when using a scanning laser system with a large acceptance angle detector. A fiducial-based ray path measurement technique is combined with an iterative CT reconstruction algorithm to reconstruct images. Methods: A water based surrounding liquid with a low viscosity was selected for imaging PRESAGE® solid dosimeters. Liquid selection was optimized to achieve as high a refractive index as possible while avoiding rotation-induced Schlieren effects. This led to a refractive index mismatch of 6% between liquid and dosimeters. Optical CT scans were performed with a fan-beam scanning-laser optical CT system with a large area detector to capture most of the refracted rays. A fiducial marker placed on the wall of a cylindrical sample occludes a given light ray twice. With knowledge of the rotation angle and the radius of the cylindrical object, the actual internal path of each ray through the dosimeter can be calculated. Scans were performed with 1024 projections of 512 data samples each, and rays were rebinned to form 512 parallel-beam projections. Reconstructions were performed on a 512 × 512 grid using 100 iterations of the SIRT iterative CT algorithm. Proof of concept was demonstrated with a uniformly attenuating solution phantom. PRESAGE® dosimeters (11 cm diameter) were irradiated with Cobalt-60

  12. High diagnostic accuracy of low-dose gated-SPECT with solid-state ultrafast detectors: preliminary clinical results

    Energy Technology Data Exchange (ETDEWEB)

    Gimelli, Alessia; Genovesi, Dario; Giorgetti, Assuero; Marzullo, Paolo [CNR, Fondazione Toscana Gabriele Monasterio, Pisa (Italy); Bottai, Matteo [University of South Carolina, Division of Biostatistics, Columbia, SC (United States); Karolinska Institutet, Division of Biostatistics, Stockholm (Sweden); Di Martino, Fabio [AOUP, UO Fisica Sanitaria, Pisa (Italy)

    2012-01-15

    Appropriate use of SPECT imaging is regulated by evidence-based guidelines and appropriateness criteria in an effort to limit the burden of radiation administered to patients. We aimed at establishing whether the use of a low dose for stress-rest single-day nuclear myocardial perfusion imaging on an ultrafast (UF) cardiac gamma camera using cadmium-zinc-telluride solid-state detectors could be used routinely with the same accuracy obtained with standard doses and conventional cameras. To this purpose, 137 consecutive patients (mean age 61 {+-} 8 years) with known or suspected coronary artery disease (CAD) were enrolled. They underwent single-day low-dose stress-rest myocardial perfusion imaging using UF SPECT and invasive coronary angiography. Patients underwent the first scan with a 7-min acquisition time 10 min after the end of the stress protocol (dose range 185 to 222 MBq of {sup 99m}Tc-tetrofosmin). The rest scan (dose range 370 to 444 MBq of {sup 99m}Tc-tetrofosmin) was acquired with a 6-min acquisition time. The mean summed stress scores (SSS) and mean summed rest scores (SRS) were obtained semiquantitatively. Coronary angiograms showed significant epicardial CAD in 83% of patients. Mean SSS and SRS were 10 {+-} 5 and 3 {+-} 3, respectively. Overall the area under the ROC curve for the SSS values was 0.904, while the areas under the ROC curves for each vascular territory were 0.982 for the left anterior descending artery, 0.931 for the left circumflex artery and 0.889 for the right coronary artery. This pilot study demonstrated the feasibility of a low-dose single-day stress-rest fasting protocol performed using UF SPECT, with good sensitivity and specificity in detecting CAD at low patient exposure, opening new perspectives in the use of myocardial perfusion in ischaemic patients. (orig.)

  13. High diagnostic accuracy of low-dose gated-SPECT with solid-state ultrafast detectors: preliminary clinical results

    International Nuclear Information System (INIS)

    Gimelli, Alessia; Genovesi, Dario; Giorgetti, Assuero; Marzullo, Paolo; Bottai, Matteo; Di Martino, Fabio

    2012-01-01

    Appropriate use of SPECT imaging is regulated by evidence-based guidelines and appropriateness criteria in an effort to limit the burden of radiation administered to patients. We aimed at establishing whether the use of a low dose for stress-rest single-day nuclear myocardial perfusion imaging on an ultrafast (UF) cardiac gamma camera using cadmium-zinc-telluride solid-state detectors could be used routinely with the same accuracy obtained with standard doses and conventional cameras. To this purpose, 137 consecutive patients (mean age 61 ± 8 years) with known or suspected coronary artery disease (CAD) were enrolled. They underwent single-day low-dose stress-rest myocardial perfusion imaging using UF SPECT and invasive coronary angiography. Patients underwent the first scan with a 7-min acquisition time 10 min after the end of the stress protocol (dose range 185 to 222 MBq of 99m Tc-tetrofosmin). The rest scan (dose range 370 to 444 MBq of 99m Tc-tetrofosmin) was acquired with a 6-min acquisition time. The mean summed stress scores (SSS) and mean summed rest scores (SRS) were obtained semiquantitatively. Coronary angiograms showed significant epicardial CAD in 83% of patients. Mean SSS and SRS were 10 ± 5 and 3 ± 3, respectively. Overall the area under the ROC curve for the SSS values was 0.904, while the areas under the ROC curves for each vascular territory were 0.982 for the left anterior descending artery, 0.931 for the left circumflex artery and 0.889 for the right coronary artery. This pilot study demonstrated the feasibility of a low-dose single-day stress-rest fasting protocol performed using UF SPECT, with good sensitivity and specificity in detecting CAD at low patient exposure, opening new perspectives in the use of myocardial perfusion in ischaemic patients. (orig.)

  14. Present status of fast neutron personnel dosimetry system based on CR-39 solid state nuclear track detectors

    International Nuclear Information System (INIS)

    Pal, Rupali; Sathian, Deepa; Jayalakshmi, V.; Bakshi, A.K.; Chougaonkar, M.P.; Mayya, Y.S.; Kumar, Valli; Babu, Rajesh; Kar, S.; Joshi, V.M.

    2011-08-01

    Neutron sources are of different types depending upon the method of production such as nuclear reactors, particle accelerators and laboratory sources. Neutron sources depending upon their energy, flux, size etc. are used for variety of applications in basic and applied sciences, neutron scattering experiments and in industry such as oil well - digging, coal mining and processing, ore processing etc. Personnel working in nuclear installations such as reactors, accelerators, spent fuel processing plants, nuclear fuel cycle operations and those working in various industries such as oil refining, oil well-digging, coal mining and processing, ore processing, etc. need to be monitored for neutron exposures, if any. Neutron monitoring is especially necessary in view of the fact that the radiation weighting factor for neutron is much higher than gamma rays and also it varies with energy. Radiological Physics and Advisory Division is involved in monitoring of personnel working in neutron fields. Around 2100 workers from 70 institutions (DAE and Non-DAE) are monitored on a quarterly basis. Neutron personnel monitoring, carried out in the country is based on Solid State Nuclear Track Detection (SSNTD) technique. In this technique, neutrons interact with hydrogen in CR-39 polymer to produce recoil protons. These protons create damages in the polymer, which are enlarged and appear as tracks when subjected to electrochemical etching (ECE). These tracks are counted in an optical system to evaluate the neutron dose. The neutron dosimetry system based on SSNTD has undergone a significant development, since it was started in 1990. The development includes upgradation of image analysis system for counting tracks, introduction of chemical etching (CE) at elevated temperatures for evaluation of dose equivalents above 10 mSv and use of carbon laser for cutting of CR-39 detectors. The entire dose evaluation process has been standardized, which includes calibration and performance tests

  15. Dosimetric characterization of a 2-D array of 223 solid state detectors for daily morning checks in Tomo Therapy equipment

    International Nuclear Information System (INIS)

    Reyes S, U.; Sosa A, M.; Vega C, H. R.

    2015-10-01

    Tomo Therapy is a new technique for the cancer treatment; however, the equipment must meet nearly all mechanical and dosimetric characteristics of a conventional linear accelerator for medical use. Daily quality controls are vital to the good operation of the equipment and thus guarantee excellent quality in the daily delivery of treatments. This paper presents the procedure of the dosimetric characterization of a two-dimensional array of 223 solid state detectors, called TomoDose of the Sun Nuclear Company. Dosimetric important criteria are established to perform these checks quickly and accurately. Dosimetric tests proposed are: repeatability, linearity, dependence of Sad and SSD. Some results are compared with readings of the ionization chamber Exradim A1SL. Finally the results of 30 consecutive days are presented to establish criteria for evidence of dose, field size, symmetry and flattening of the radiation beam on Tomo Therapy equipment. Expected values for daily verification are: Dose constancy of 194.89 c Gy, σ= 1.31 c Gy, symmetry in the X axis of -0.19 %, σ=0.08 %, symmetry in the Y axis of 1.66 %, σ= 0.05 %, flattened in the X axis of 25.71 %, σ= 0.05 % and flattened in the Y axis of 6.41 %, σ= 10.23 %. Field sizes obtained were 40.45 cm in the X axis and 5.10 on the Y axis, with standard deviations of 0.02 cm and 0.01 cm, respectively. TomoDose dosimetric values, compared to the values obtained with ionization chamber, presented differences smaller than 2%. (Author)

  16. Performance of thallium bromide semiconductor detectors produced by repeated Bridgman method

    International Nuclear Information System (INIS)

    Santos, Robinson Alves dos; Costa, Fabio Eduardo da; Martins, Joao Francisco Trencher; Hamada, Margarida M.

    2009-01-01

    TlBr crystals have been grown by the Repeated Bridgman method from commercial TlBr materials and characterized to be used as radiation detectors. We have shown that the Repeated Bridgman is effective to reduce the concentration of impurities in TlBr. It was observed that detectors fabricated from higher purity crystal exhibit significant improvement in performance compared to those produced from low purity crystals. However, problems still exist in TlBr detectors, due to the low charge carrier collection efficiency, which is probably caused by additional impurities or defects incorporated during crystal growth and detector fabrication processes. (author)

  17. Converting Hg-1212 to Tl-2212 via Tl-Hg cation exchange in combination with Tl cation intercalation

    International Nuclear Information System (INIS)

    Zhao Hua; Wu, Judy Z

    2007-01-01

    In a cation exchange process developed recently for epitaxy of HgBa 2 CaCu 2 O 6 (Hg-1212) thin films, TlBa 2 CaCu 2 O 7 (Tl-1212) or Tl 2 Ba 2 CaCu 2 O 9 (Tl-2212) precursor films were employed as the precursor matrices and Hg-1212 was obtained by replacing Tl cations on the precursor lattice with Hg cations. The reversibility of the cation exchange dictates directly the underlying mechanism. Following our recent success in demonstrating a complete reversibility within '1212' structure, we show the conversion from Hg-1212 to Tl-2212 can be achieved via two steps: conversion from Hg-1212 to Tl-1212 followed by Tl intercalation to form double Tl-O plans in each unit cell. The demonstrated reversibility of the cation exchange process has confirmed the process is a thermal perturbation of weakly bonded cations on the lattice and the direction of the process is determined by the population ratio between the replacing cations and that to be replaced

  18. arXiv Performance of a full scale prototype detector at the BR2 reactor for the SoLid experiment

    CERN Document Server

    Abreu, Y.; Arnold, L.; Ban, G.; Beaumont, W.; Bongrand, M.; Boursette, D.; Castle, B.C.; Clark, K.; Coupé, B.; Cussans, D.; De Roeck, A.; D'Hondt, J.; Durand, D.; Fallot, M.; Ghys, L.; Giot, L.; Guillon, B.; Ihantola, S.; Janssen, X.; Kalcheva, S.; Kalousis, L.N.; Koonen, E.; Labare, M.; Lehaut, G.; Manzanillas, L.; Mermans, J.; Michiels, I.; Moortgat, C.; Newbold, D.; Park, J.; Pestel, V.; Petridis, K.; Piñera, I.; Pommery, G.; Popescu, L.; Pronost, G.; Rademacker, J.; Ryckbosch, D.; Ryder, N.; Saunders, D.; Schune, M.-H.; Simard, L.; Vacheret, A.; Van Dyck, S.; Van Mulders, P.; van Remortel, N.; Vercaemer, S.; Verstraeten, M.; Weber, A.; Yermia, F.

    2018-05-03

    The SoLid collaboration has developed a new detector technology to detect electron anti-neutrinos at close proximity to the Belgian BR2 reactor at surface level. A 288 kg prototype detector was deployed in 2015 and collected data during the operational period of the reactor and during reactor shut-down. Dedicated calibration campaigns were also performed with gamma and neutron sources. This paper describes the construction of the prototype detector with a high control on its proton content and the stability of its operation over a period of several months after deployment at the BR2 reactor site. All detector cells provide sufficient light yields to achieve a target energy resolution of better than 20%/√E(MeV). The capability of the detector to track muons is exploited to equalize the light response of a large number of channels to a precision of 3% and to demonstrate the stability of the energy scale over time. Particle identification based on pulse-shape discrimination is demonstrated with calibration so...

  19. Computerized study with 201Tl of the gold thyroid node

    International Nuclear Information System (INIS)

    Palermo, F.; Saitta, B.; Coghetto, F.; Tiberio, M.; Caldato, L.

    1982-01-01

    Because of its physical and potassium-metabolic characteristics 201 Tl is more suitable than 131 Cs for radioisotopic studies of the cold thyroid nodule, with the further diagnostic possibility of quantitatively assessing intranodular behaviour for a specific differentiation among different kinds of neoformations. Using a gamma-camera on line with a computer data processing device, sequential scintiscans were recorded for the first 20-30 min after i.v. administration of 15-20 μCi/kg of radiothallium; delayed sequences were taken at 40-60 min if intranodular uptake appeared. A quantitative appraisal was made of the differential 201 Tl uptake-ratio between nodule and healthy thyroid tissue (density-index) and the multiparameter analysis of thyroid time/activity curves generated on the relative regions of interest (ROIs). This computerized study, in 120 out of 293 patients submitted to this radiothallium test, has shown a) diagnostic agreement between clinical-histological and radioisotopic findings in 76 out of 79 colloid-cystic or degenerative neoformations, in all 16 malignant and in 23 out of 25 hyperplastic benign nodules; b) significant statistical difference of the density-index in solid versus cystic but not between benign and malignant nodules; c) different 201 Tl kinetics behaviour in different kinds of solid thyroid lesions with a satisfactory statistical difference of the radiothallium nodular dissappearance-index. (orig.) [de

  20. Successful use of a linear position-sensitive neutron detector in solid state physics and materials science

    International Nuclear Information System (INIS)

    Schefer, J.; Fischer, P.; Heer, H.; Isacson, A.; Koch, M.; Thut, R.

    1991-01-01

    The double axis multicounter diffractometer (DMC) installed at the 10 MW reactor SAPHIR (PSI) has been designed as a good flux-good resolution (presently Δd/d≥4x10 -3 ) neutron poder diffractometer. The detector bank is based on a commercial position-sensitive linear BF 3 detector which may be automatically and precisely positioned on air cushions on inexpensive floors. This detector type has an 80deg angular opening, not allowing any standard collimation in front of the detector. We therefore developed an oscillating collimator system allowing easy use of the instrument even with sample environments such as a dilution cryostat. (orig.)

  1. Towards time-of-flight PET with a semiconductor detector

    Science.gov (United States)

    Ariño-Estrada, Gerard; Mitchell, Gregory S.; Kwon, Sun Il; Du, Junwei; Kim, Hadong; Cirignano, Leonard J.; Shah, Kanai S.; Cherry, Simon R.

    2018-02-01

    The feasibility of using Cerenkov light, generated by energetic electrons following 511 keV photon interactions in the semiconductor TlBr, to obtain fast timing information for positron emission tomography (PET) was evaluated. Due to its high refractive index, TlBr is a relatively good Cerenkov radiator and with its wide bandgap, has good optical transparency across most of the visible spectrum. Coupling an SiPM photodetector to a slab of TlBr (TlBr-SiPM) yielded a coincidence timing resolution of 620 ps FWHM between the TlBr-SiPM detector and a LFS reference detector. This value improved to 430 ps FWHM by applying a high pulse amplitude cut based on the TlBr-SiPM and reference detector signal amplitudes. These results are the best ever achieved with a semiconductor PET detector and already approach the performance required for time-of-flight. As TlBr has higher stopping power and better energy resolution than the conventional scintillation detectors currently used in PET scanners, a hybrid TlBr-SiPM detector with fast timing capability becomes an interesting option for further development.

  2. Analytical investigation of energy spectrums of beta rays emitted from 90Sr and 204Tl radioisotopes

    International Nuclear Information System (INIS)

    Yalcin, S.

    2011-01-01

    The energy spectra of beta rays emitted from 90 Sr and 204 Tl radioisotopes were obtained by using a silicon surface barrier detector with a 1000 μm depleted layer and 50 mm 2 effective area. The detector response function is interpreted by making use of range distributions of mono-energetic electrons in matter and by assuming a linear energy loss along the range in the depleted layer of the detector. An analytical expression is given for pulse height distribution obtained in the surface barrier detector. A good agreement is observed between the experimental results and theoretical interpretation. (author)

  3. Characterization of solid D{sub 2} as a source material for ultra cold neutrons (UCN) and development of a detector concept for the detection of protons from the neutron decay

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, Axel Reimer

    2008-12-09

    In the first part of this thesis, properties of the UCN-converter material solid deuterium (sD{sub 2}) are studied. A series of investigations of various sD{sub 2} crystals by means of optical spectroscopy and neutron scattering resulted in: (i) a freezing technique suitable for UCN sources (ii) an efficient method to achieve a high ortho concentration, (iii) a direct way to calculate the UCN production cross-section from the dynamic structure factor S(q, {omega}), (iv) the identification of six excitations responsible for UCN production (v) the interpretation of one excitation at E=12 meV as a multi-phonon process (vi) the discovery of an additional spin-dependent UCN loss mechanism at q=2.1A{sup -1} and E=1.8 meV. A complementary series of experiments was performed at the FRMII, testing the production of UCN with the studied sample preparation after different the characterization mentioned above. Besides establishing a technique for annealing sD{sub 2} crystals to improve the UCN production rate, an additional loss cross section ({sigma}{sub x}=8 barn at 4.5 K indirect proportional to the ortho concentration) was found. Based on these findings, a new conceptual layout of the miniD{sub 2} source was developed. In the second part, the diffuse scattering probability f and the loss probability per wall collision {mu} were measured for differently prepared UCN guides using the storageand the so called two-hole method. Electropolished, rough stainless steel and Al tubes with different coatings at temperature variation and surface conditions were measured. The third part deals with the development of a proton detector for the neutron lifetime experiment PENeLOPE, which is based on gravitational and magnetic UCN storage and counting of the protons from the decay. A concept for a large-area proton detector based on thin scintillation counters operating in cryogenic environment was developed based on simulations and experimental studies. In addition to the characterization

  4. Characterization of solid D2 as a source material for ultra cold neutrons (UCN) and development of a detector concept for the detection of protons from the neutron decay

    International Nuclear Information System (INIS)

    Mueller, Axel Reimer

    2008-01-01

    In the first part of this thesis, properties of the UCN-converter material solid deuterium (sD 2 ) are studied. A series of investigations of various sD 2 crystals by means of optical spectroscopy and neutron scattering resulted in: (i) a freezing technique suitable for UCN sources (ii) an efficient method to achieve a high ortho concentration, (iii) a direct way to calculate the UCN production cross-section from the dynamic structure factor S(q, ω), (iv) the identification of six excitations responsible for UCN production (v) the interpretation of one excitation at E=12 meV as a multi-phonon process (vi) the discovery of an additional spin-dependent UCN loss mechanism at q=2.1A -1 and E=1.8 meV. A complementary series of experiments was performed at the FRMII, testing the production of UCN with the studied sample preparation after different the characterization mentioned above. Besides establishing a technique for annealing sD 2 crystals to improve the UCN production rate, an additional loss cross section (σ x =8 barn at 4.5 K indirect proportional to the ortho concentration) was found. Based on these findings, a new conceptual layout of the miniD 2 source was developed. In the second part, the diffuse scattering probability f and the loss probability per wall collision μ were measured for differently prepared UCN guides using the storageand the so called two-hole method. Electropolished, rough stainless steel and Al tubes with different coatings at temperature variation and surface conditions were measured. The third part deals with the development of a proton detector for the neutron lifetime experiment PENeLOPE, which is based on gravitational and magnetic UCN storage and counting of the protons from the decay. A concept for a large-area proton detector based on thin scintillation counters operating in cryogenic environment was developed based on simulations and experimental studies. In addition to the characterization of CsI(Tl) and CsI scintillators, a

  5. Superconducting transition in TlBiTe/sub 2/ and TlTe compounds

    Energy Technology Data Exchange (ETDEWEB)

    Kantser, V G; Popovich, N S; Sidorenko, A S

    1985-10-01

    On the basis of zone structure calculation for TlBiTe/sub 2/ and TlTe it is found that TlBiTe/sub 2/ is a narrow-gap semiconductor and TlTe is a p-metal. At Tsub(c)=0.19 K TlTe is found to experience the superconducting transition. In TlBiTe/sub 2/ superconductivity is not observed to occur up to 0.05 K, since there is a possibility of occupying the high density of states zones because they are remote from actual ones. The earlier discovered superconducting transition in TlBiTe/sub 2/ is inherent in the alien phase of TlTe.

  6. Tl response of KMgF3: Lu + PTFE at ultraviolet radiation

    International Nuclear Information System (INIS)

    Gonzalez, P.R.; Alarcon, N.G.; Furetta, C.; Azorin, J.

    2003-01-01

    Ionizing radiation has different types of interaction with a crystalline solid. However, only few effects are interesting to optimize some thermoluminescent (Tl) properties of certain Tl materials. This paper presents results obtained by irradiating KMgF 3 : Lu + Ptfe Tl dosimeters with ultraviolet (UV) radiation previously exposed to gamma radiation. These results showed that those dosimeters not exposed previously to gamma radiation did not presented any Tl signal. Meanwhile, those previously submitted to gamma irradiation showed that their sensitivity was increased as the gamma dose increased. The glow curve of sensitized KMgF 3 : Lu + Ptfe exposed to UV radiation, presented the dosimetric pea at 212 C. This makes this material to be promissory for measuring UV radiation. (Author)

  7. Study of the optical properties and the carbonaceous clusters in thermally-annealed CR-39 and Makrofol-E polymer-based solid-state nuclear track detectors

    International Nuclear Information System (INIS)

    El Ghazaly, M.

    2012-01-01

    The induced modifications in the optical properties of CR-39 and Makrofol-E polymer-based solid state nuclear track detectors were investigated after thermal annealing at a temperature of 200 .deg. C for different durations. The optical properties were studied using an UV-visible spectrophotometer. From the UV-visible spectra, the direct and the indirect optical band gaps, Urbach's energies, and the number of carbon atoms in a cluster were determined. The absorbance of CR-39 plastic detector was found to decrease with increasing annealing time while the absorbance of Makrofol-E decreased with increasing annealing time. The width of the tail of localized states in the band gap ΔE was evaluated with the Urbach method. The optical energy band gaps were obtained from the direct and the indirect allowed transitions in K-space. Both of the direct and the indirect band gaps of the annealed CR-39 detector decrease with increasing annealing time while in Makrofol-E, they decreased after an annealing time of 15 minute and then showed no remarkable changes for a prolonged annealing times. Urbach's energy decreased significantly for both CR-39 and Makrofol-E with increasing annealing time. The number of carbon atoms in a cluster increased in the CR-39 detector with increasing annealing time while it decreased with increasing annealing time for Makrofol-E. We may conclude that the CR-39 detector undergoes greater modifications than the Makrofol-E detector upon thermal annealing at 200 .deg. C. In conclusion, the induced modifications in the optical properties of CR-39 and Makrofol-E are correlated with the temperature and the duration of annealing.

  8. Study of gamma irradiation effects on the etching and optical properties of CR-39 solid state nuclear track detector and its application to uranium assay in soil samples

    International Nuclear Information System (INIS)

    Amol Mhatre; Kalsi, P.C.

    2011-01-01

    The gamma irradiation effects in the dose range of 2.5-43.0 Mrad on the etching and optical characteristics of CR-39 solid state nuclear track detector (SSNTD) have been studied by using etching and UV-Visible spectroscopic techniques. From the measured bulk etch rates at different temperatures, the activation energies for bulk etching at different doses have also been determined. It is seen that the bulk etch rates increase and the activation energies for bulk etching decrease with the increase in gamma dose. The optical band gaps of the unirradiated and the gamma -irradiated detectors determined from the UV-Visible spectra were found to decrease with the increase in gamma dose. These results have been explained on the basis of scission of the detector due to gamma irradiation. The present studies can be used for the estimation of gamma dose in the range of 2.5-43.0 Mrad and can also be used for estimating track registration efficiency in the presence of gamma dose. The CR-39 detector has also been applied for the assay of uranium in some soil samples of Jammu city. (author)

  9. State of the art of solid state dosimetry

    International Nuclear Information System (INIS)

    Souza, Susana O.; Yamamoto, Takayoshi; D'Errico, Francesco

    2014-01-01

    Passive solid-state detectors still dominate the personal dosimetry field. This article provides state of the art in this field and summarizes the most recent works presented on TL, OSL and RPL during the 17th International Conference on Solid State Dosimetry held in Recife in September 2013. The Article contains in particular the techniques Thermoluminescence (TL), Optically Stimulated Luminescence (OSL), radio photoluminescence (RPL). Thermoluminescence has the biggest advantage of the wide availability of commercial materials for dosimetry, and the nature tissue-equivalent of several of these materials. The limitation of the TL dosimetry presents fading luminance signal and the need for high temperatures to obtain the signal. The Optically Stimulated Luminescence has the advantages of high sensitivity, the possibility of multiple reading, while its limit is the need to use response compensating filters in addition to the high cost of equipment and dosimeters still restricted very few options trading . The radio photoluminescence has a reading that is completely non-destructive, but their dosimeters present lack of tissue-equivalent and a high cost. Presents the details of the techniques and the advantages and limitations of each of these will be discussed

  10. Effect of neutron irradiation on etching, optical and structural properties of microscopic glass slide used as a solid state nuclear track detector

    International Nuclear Information System (INIS)

    Singh, Surinder; Kaur Sandhu, Amanpreet; Prasher, Sangeeta; Prakash Pandey, Om

    2007-01-01

    Microscopic glass slides are soda-lime glasses which are readily available and are easy to manufacture with low production cost. The application of these glasses as nuclear track detector will help us to make use of these glasses as solid-state nuclear track detector. The present paper describes the variation in the etching, optical and structural properties of the soda-lime microscopic glass slides due to neutron irradiation of different fluences. The color transformation and an increase in the optical absorption with neutron irradiation are observed. Both the bulk and track etch rates are found to increase with neutron fluence, thus showing a similar dependence on neutron fluence, but the sensitivity remains almost constant

  11. Prolate yrast cascade in 183Tl

    International Nuclear Information System (INIS)

    Reviol, W.; Carpenter, M. P.; Janssens, R. V. F.; Jenkins, D.; Toth, K. S.; Bingham, C. R.; Riedinger, L. L.; Weintraub, W.; Cizewski, J. A.; Lauritsen, T.

    2000-01-01

    The yrast sequence in 183 Tl has been studied for the first time in recoil-mass selected γ-ray spectroscopic measurements. A rotational-like cascade of seven transitions is established down to the band head with probable spin and parity (13/2 + ). Unlike in the adjacent odd-mass Tl nuclei, prompt γ decay from the yrast band to a lower lying weakly deformed (oblate) structure is not observed. These features are consistent with the predicted drop of the prolate band head in 183 Tl compared to 185 Tl. The implications for the prolate energy minimum in odd-mass Tl nuclei at the neutron i 13/2 midshell (N=103) are discussed. (c) 2000 The American Physical Society

  12. Analysis and modelling of the performance of a new solid-state detector in nuclear medicine: from Anger- to Semiconductor-detectors

    International Nuclear Information System (INIS)

    Imbert, L.

    2012-01-01

    Myocardial single-photon emission computed tomography (SPECT) is considered as the gold standard for the diagnosis of coronary artery disease. Developed in the 1980's with rotating Anger gamma cameras, this technique could be dramatically enhanced by new imaging systems working with semiconductor detectors and which performances are clearly enhanced. Two semiconductor cameras, dedicated to nuclear cardiology and equipped with Cadmium Zinc Telluride detectors, have been recently commercialized: the Discovery NM- 530c (General Electric) and the DSPECT (Spectrum Dynamics). The performances of these CZT cameras were compared: 1) by a comprehensive analysis of phantom and human SPECT images considered as normal and 2) with the parameters commonly recommended for SPECT recording and reconstruction. The results show the superiority of the CZT cameras in terms of detection sensitivity, spatial resolution and contrast-to-noise ratio, compared to conventional Anger cameras. These properties might lead to dramatically reduce acquisition times and/or the injected activities. However, the limits of these new CZT cameras, as well as the mechanism of certain artefacts, remain poorly known. This knowledge could be enhanced by a numerical modeling of the DSPECT camera, and this might also help to optimize acquisition and reconstruction parameters. We developed a simulator where the geometry of the detectors of the DSPECT camera and their energy response were modeled in the GATE platform. In order to validate this simulator, actually recorded data were compared with simulated data through three performance parameters: detection sensitivity, spatial resolution and energy resolution. Results were in agreement between simulated and actually recorded data. This observation validates the DSPECT simulator and opens the door to further studies planed to optimize the recorded and reconstruction processes, especially for complex protocols such as simultaneous dual-radionuclide acquisition

  13. Report of the compact detector subgroup

    International Nuclear Information System (INIS)

    Kirkby, J.; Kondo, T.; Olsen, S.L.

    1988-01-01

    This report discusses different detector designs that are being proposed for Superconducting Super Collider experiments. The detectors discussed are: Higgs particle detector, Solid State Box detector, SMART detector, muon detection system, and forward detector. Also discussed are triggering strategies for these detectors, high field solenoids, barium fluoride option for EM calorimetry, radiation damage considerations, and cost estimates

  14. The cosmic ray actinide charge spectrum derived from a 10 m2 array of solid state nuclear track detectors in Earth orbit

    International Nuclear Information System (INIS)

    Donnelly, J.; Thompson, A.; O'Sullivan, D.; Drury, L.O'C.; Wenzel, K.-P.

    2001-01-01

    The DIAS-ESTEC Ultra Heavy Cosmic Ray Experiment (UHCRE) on the Long Duration Exposure Facility, collected approximately 3000 cosmic ray nuclei with Z>65 in the energy region E>1.5 GeV nucleon -1 during a six year exposure in Earth orbit. The entire accessible collecting area of the solid state nuclear track detector (SSNTD) array has been scanned for actinides, yielding a sample of 30 from an exposure of ∼150 m 2 sr yr. The UHCRE experimental setup is described and the observed charge spectrum presented. The current best value for the cosmic ray actinide relative abundance, (Z>88)/(74≤Z≤87), is reported

  15. Results of solid state nuclear track detector technique application in radon detection, by alpha particles tracks, for uranium prospecting in Caetite (BA-Brazil)

    International Nuclear Information System (INIS)

    Moraes, M.A.P.V. de; Khouri, M.T.F.C.

    1988-11-01

    The solid state nuclear track detector technique has been used in radon detection, by alpha particles tracks for uranium prospecting on the ground in Caetite city (Bahia-Brazil). The sensitive film to alpha particles used were CA 8015 exposed during 15 days and the results of three anomalies of this region are showed in a form of maps, made with the density of tracks obtained, and were compared with scintillation counter measurements. The technique showed to be simple and an effective auxiliary for the prospection of uranium ore bodies. The initial uranium exploration costs can be reduced by using this technique. (author) [pt

  16. Influence of external and internal conditions of detector sample treatment on the particle registration sensitivity of Solid State Nuclear Track Detectors of type CR-39

    International Nuclear Information System (INIS)

    Hermsdorf, Dietrich

    2012-01-01

    The sensitivity of charged particle registration with SSNTD is the most important parameter to decide about the applicability of those detectors in research, technology and environmental dosimetry. The sensitivity is strongly influenced by the treatment of detector samples before, during and after the exposure and the final evaluation process by chemical etching. Whereas changes in detection properties by external environmental influences are generally considered, the dependences on the etching conditions are ignored. Commonly the sensitivity is assumed to compensate variations in the etching conditions for track revealing. In the present work the validity of this hypothesis will be checked. In the frame of the existing database the sensitivity is not really independent on variations in etching temperatures and should be corrected for differences in the activation energies for stimulation of the bulk and track etching process. Differences in the concentration dependence may be of minor importance. Furthermore, the registration sensitivity depends on environmental conditions before, during and after the irradiation with particles under investigation. Such external parameters are the air pressure, the sample temperature and modification of bulk material by out-gassing in vacuum and exposure to γ-rays. However, the available database is insufficient and inaccurate to draw final conclusions on the detection properties of SSNTD under various external and internal conditions.

  17. Preparation of bubble damage detectors

    International Nuclear Information System (INIS)

    Tu Caiqing; Guo Shilun; Wang Yulan; Hao Xiuhong; Chen Changmao; Su Jingling

    1997-01-01

    Bubble damage detectors have been prepared by using polyacrylamide as detector solid and freon as detector liquid. Tests show that the prepared detectors are sensitive to fast neutrons and have proportionality between bubble number and neutron fluence within a certain range of neutron fluence. Therefore, it can be used as a fast neutron detector and a dosimeter

  18. High sensitivity isotope analysis with a 252Cf--235U fueled subcritical multiplier and low background photon detector systems

    International Nuclear Information System (INIS)

    Wogman, N.A.; Rieck, H.G. Jr.; Laul, J.C.; MacMurdo, K.W.

    1976-09-01

    A 252 Cf activation analysis facility has been developed for routine multielement analysis of a wide variety of solid and liquid samples. The facility contains six sources of 252 Cf totaling slightly over 100 mg. These sources are placed in a 93 percent 235 U-enriched uranium core which is subcritical with a K effective of 0.985 (multiplication factor of 66). The system produces a thermal flux on the order of 10 +1 neutrons per square centimeter per second. A pneumatic rabbit system permits automatic irradiation, decay, and counting regimes to be performed unattended on the samples. The activated isotopes are analyzed through their photon emissions with state-of-the-art intrinsic Ge detectors, Ge(Li) detectors, and NaI(Tl) multidimensional gamma ray spectrometers. High efficiency (25 percent), low background, anticoincidence shielded Ge(Li) gamma ray detector systems have been constructed to provide the lowest possible background, yet maintain a peak to Compton ratio of greater than 1000 to 1. The multidimensional gamma ray spectrometer systems are composed of 23 cm diameter x 20 cm thick NaI(Tl) crystals surrounded by NaI(Tl) anticoincidence shields. The detection limits for over 65 elements have been determined for this system. Over 40 elements are detectable at the 1 part per million level at a precision of +-10 percent

  19. A portable in situ NaI(Tl) γ spectroscopy system

    International Nuclear Information System (INIS)

    Wang Bairong; Dong Binjiang; Zeng Liping

    1999-01-01

    The author describes a portable in situ NaI(Tl) γ spectroscopy system, which consists of a NaI(Tl) scintillation detector, an integrative spectroscopy card, a notebook computer and the spectroscopy software. The spectrometer addresses applications in environmental or nuclear accident in situ γ spectroscopy measurements, and gives valid quantitative results of radionuclide concentrations per unit volume (Bq/kg) or per unit area (Bq/cm 2 ) in the soil and absorbed dose rate in air 1 m above ground (Gy/h)

  20. The unfolding of NaI(Tl) γ-ray spectrum based on maximum likelihood method

    International Nuclear Information System (INIS)

    Zhang Qingxian; Ge Liangquan; Gu Yi; Zeng Guoqiang; Lin Yanchang; Wang Guangxi

    2011-01-01

    NaI(Tl) detectors, having a good detection efficiency, are used to detect gamma rays in field surveys. But the poor energy resolution hinders their applications, despite the use of traditional methods to resolve the overlapped gamma-ray peaks. In this paper, the maximum likelihood (ML) solution is used to resolve the spectrum. The ML method,which is capable of decomposing the peaks in energy difference of over 2/3 FWHM, is applied to scale NaI(Tl) the spectrometer. The result shows that the net area is in proportion to the content of isotopes and the precision of scaling is better than the stripping ration method. (authors)

  1. Intercomparison of Environmental Dosemeters Using Various TL Materials and Dosimetry Systems

    International Nuclear Information System (INIS)

    Crnic, B.; Gobec, S.; Zorko, B.; Knezevic, Z.; Majer, M.; Ranogajec-Komor, M.

    2013-01-01

    The aim of the present work was to compare the ambient dose equivalent (H*(10)) values determined at 20 sites around NPP Krško, using different thermoluminescence (TL) materials and various dosimetry systems. The H*(10) was measured by the CaF 2 :Mn (TLD-400) provided by the Jozef Stefan Institute (JSI) Ljubljana, Slovenia. These dosemeters were deployed in the environment in plastic bags and suspended inside the plastic bottles. On the other hand the Ruder Boskovic Institute (RBI), Zagreb, Croatia applied LiF:Mg,Cu,P (TLD-100H), CaF 2 :Mn, Al 2 O 3 :C TL detectors and radiophotoluminescence (RPL) glass dosemeters type SG1. They were placed at the same locations in as much as possible same conditions as JSI detectors. According to the protocol established for this intercomparison, the control and transport detectors (not deployed in the environment) were held in dark storage containers and used to determine the background radiation. The TL responses were corrected for individual sensitivity of the TL detectors which is an important factor after the calibration irradiations. The calibration irradiations were performed by 137Cs sources provided in Secondary Standard Dosimetry Laboratory facilities at the JSI and RBI. The results obtained by different TL materials and different dosimetry systems show interesting features especially concerning local environmental peculiarities. The H*(10) obtained by the dosemeters of various types deployed in the countryside fluctuate less than 10 %. The outcome should emphasize also in the manner that the results obtained and reported in the intercomparison are traceable to the primary standards.(author)

  2. Development of a new scanning method for solid states track detector in the heavy nuclei explorer experiment (HNX-ECCO)

    International Nuclear Information System (INIS)

    Yasuda, N.; Sekiguchi, M.; Nakamura, S.; Kitamura, T.; Tawara, H.; Doke, T.

    2001-01-01

    The HNX (Heavy Nuclear eXplorer) project has been tentatively accepted as one of the NASA's Small Explorer (SMEX) Program. Purpose of this project is the measurement of abundances for heavy nuclei in galactic cosmic rays (GCRs). This information will contribute to get a great knowledge for the origin of GCR. HNX has two large and high sensitive detectors, ENTICE (Energetic Trans-Ion Composition Experiment) and ECCO (Extremely Heavy Cosmic-ray Composition Observer). ECCO experimental module consists the large BP-1 glass detectors (total area; 23 m 2 ), will collect the GCRs (∼2,000 events for Pt-group and ∼100 events for actinide) with its high charge resolution (<0.35 e) in space at least 3 years. We report the outline of HNX project and the new techniques for the measurement of large glass detectors. (author)

  3. Calibration of a special neutron dosemeter based on solid-state track detectors and fission radiators in various neutron fields

    International Nuclear Information System (INIS)

    Doerschel, B.; Krusche, M.; Schuricht, V.

    1980-01-01

    The calibration of a personnel neutron dosemeter in different neutron fields is described. The badge-like dosemeter contains 5 detectors: polycarbonate foil (10 μm, Makrofol KG), 232 Th, natural uranium, natural uranium with boron, and natural uranium with cadmium. Detector sensitivity and calibration factors have been calculated and measured in radiation fields of 252 Cf fission neutrons, WWR-S reactor neutrons with and without Cd and Fe shielding, 3-MeV (d,t) generator neutrons, and 238 PuBe neutrons. Measurement range and achievable accuracy are discussed from the point of view of applying the dosemeter in routine and emergency uses

  4. Measurements of energetic ions produced by high-energy laser pulses by means of solid-state nuclear track detectors

    Czech Academy of Sciences Publication Activity Database

    Szydlowski, A.; Badziak, A.; Parys, P.; Wolowski, J.; Woryna, E.; Jungwirth, Karel; Králiková, Božena; Krása, Josef; Láska, Leoš; Pfeifer, Miroslav; Rohlena, Karel; Skála, Jiří; Ullschmied, Jiří; Boody, F. D.; Gammino, S.; Torrisi, L.

    2004-01-01

    Roč. 7, č. 3 (2004), s. 327-332 ISSN 1093-3611 Institutional research plan: CEZ:AV0Z1010921 Keywords : iodine laser * nuclear track detectors * ions Subject RIV: BH - Optics, Masers, Lasers Impact factor: 0.194, year: 2004

  5. Some design considerations for a large solid angle charged plus neutrals detector for e+e/sup /minus// storage rings

    International Nuclear Information System (INIS)

    Mast, T.; Nelson, J.

    1974-08-01

    We describe here the relations between various design parameters, costs, resolutions, geometry, etc., that we have found useful in thinking about charged and neutral particle detectors for SPEAR and PEP. A great many alternatives exist for the various components of these detectors: solenoid vs. Helmholtz coils for the magnet, normal versus superconducting magnets, active converters versus passive converters for the gammas, different gamma detection methods, different return yoke configurations, etc. We have thought most about a system based upon a solenoid magnet with drift chambers inside for charged particle detection and lead glass outside for gamma detection. Consequently most of the formulae and figures in this paper are oriented toward that configuration. A great many other configurations have been discussed as possibilities for PEP detectors. Since the constraints ($, manpower, electrical power) and the physics of interest at PEP are still unknown we consider the present configuration to be only one of many possibilities. Each of the possible configurations needs to be carefully studied to understand its limitations and to optimize the design within those limitations. In that spirit we present here some of the tools needed for understanding the design of a solenoidal detector. 18 figs

  6. Analytical formulae to calculate the solid angle subtended at an arbitrarily positioned point source by an elliptical radiation detector

    International Nuclear Information System (INIS)

    Abbas, Mahmoud I.; Hammoud, Sami; Ibrahim, Tarek; Sakr, Mohamed

    2015-01-01

    In this article, we introduce a direct analytical mathematical method for calculating the solid angle, Ω, subtended at a point by closed elliptical contours. The solid angle is required in many areas of optical and nuclear physics to estimate the flux of particle beam of radiation and to determine the activity of a radioactive source. The validity of the derived analytical expressions was successfully confirmed by the comparison with some published data (Numerical Method)

  7. RDM lifetime measurements in 187Tl

    International Nuclear Information System (INIS)

    Chamoli, S.K.; Joshi, P.; Kumar, A.; Govil, I.M.; Mukherjee, G.; Singh, R.P.; Muralithar, S.; Bhowmik, R.K.

    2003-01-01

    The present work is an attempt to study the shape changes in 187 Tl through a measurement of electromagnetic transition probabilities of the high spin states. The Doppler shifted recoil distance technique was used to measure the lifetimes

  8. Disquisition and technical alteration about TL apparatus

    International Nuclear Information System (INIS)

    Wang Guangxiang; Li Mingliang

    2002-01-01

    The author simply introduces the disadvantage of TL apparatus controlled by single chip. The project uses the PC computer to replace single chip control. So it must be changed the interface and made up a software with Chinese

  9. Cryogenic detectors

    International Nuclear Information System (INIS)

    Zehnder, A.

    1987-01-01

    Presently the development of new large scale detector systems, used in very high energy physics experiments, is very active. In the low energy range, the introduction of charge coupled devices allows improved spacial and energy resolution. In the keV region, high resolution can only be achieved via the well established diffraction spectrometers with the well-known disadvantage of a small throughput. There exist no efficient detectors for non-ionizing radiation such as coherent nuclear scattering of weakly interacting particles. The development of high resolution solid state detectors in the keV-region with the possibility of nuclear recoil detection is therefore highly desired. Such detectors applied in astro and particle physics would thus allow one to obtain new information not achievable otherwise. Three types of cryogenic detectors exist: Calorimeters/Bolometers. This type is sensitive to the produced excess phonons and measures the deposited energy by detecting the heat pulses. Excess charge carriers should be used to produce phonons. Tunneling junctions. This type is sensitive to excess charge produced by the Cooper pair breakup. Excess phonons should be used to break up Cooper pairs. Superheated superconducting granules (SSG). An SSG detector consists of granules, the metastability of which is disturbed by radiation. The Meissner effect then causes a change in the field distribution of the applied external field, which can be detected. The present paper discusses the basic principle of calorimetric and tunneling junction detectors and some of their applications. 26 refs., 7 figs., 1 tab

  10. Performance of novel materials for radiation detection: Tl{sub 3}AsSe{sub 3}, TlGaSe{sub 2}, and Tl{sub 4}HgI{sub 6}

    Energy Technology Data Exchange (ETDEWEB)

    Kahler, D., E-mail: david.kahler@ngc.com [Northrop Grumman Corporation, ES-ATL, 1212 Winterson Road, Linthicum, MD 21090 (United States); Singh, N.B.; Knuteson, D.J.; Wagner, B.; Berghmans, A.; McLaughlin, S.; King, M.; Schwartz, K. [Northrop Grumman Corporation, ES-ATL, 1212 Winterson Road, Linthicum, MD 21090 (United States); Suhre, D.; Gotlieb, M. [DRS Scientific, 300 Oak Lake Road, New Kensington, PA 15068 (United States)

    2011-10-01

    In this paper we report on the electrical characteristics of three novel ternary compounds, Tl{sub 3}AsSe{sub 3} (TAS), TlGaSe{sub 2} (TGS), and Tl{sub 4}HgI{sub 6} (THI), pertaining to their use as radiation detectors. The details for growth and material characterization are not presented. A semiconductor based gamma ray detector requires a material with high Z, high density, high resistivity, appropriate bandgap (1.5-2 eV), low energy/electron-hole pair, and a high {mu}{tau} product. CZT is currently the best semiconductor material for room temperature gamma ray spectroscopy; however, it is extremely difficult to produce large volumes of detector grade material, making it expensive and in limited supply. DNDO/DHS began searching for other materials that might perform as well as CZT but be easier to grow and in the end lower the cost. For this purpose, we investigated the above three materials as possible replacements for CZT as gamma ray detectors. The bulk resistivity, I-V curves, X-ray response, and gamma ray response measurements for doped and undoped crystals are presented and discussed. TAS shows good X-ray and gamma ray response, but has poor resistivity, which results in large dark current and poor spectral response. TGS has good resistivity, but shows poor X-ray and gamma ray response. THI has excellent resistivity, shows some X-ray and gamma ray response, and has great potential as a gamma ray detector.

  11. Progress and problems with automated TL dating

    International Nuclear Information System (INIS)

    McKerrell, H.; Mejdahl, V.

    1981-01-01

    A number of basic problems connected with the measurement of beta and gamma dose-rates are discussed, and the possibility of using low-temperature peaks in quartz and feldspar for dose-rate measurements is examined. Preliminary results of TL measurements on individual grains of quartz and feldspar are presented. A TL dating method based on the difference in the archaeological dose received by potassium feldspar and quartz grains is proposed. (author)

  12. Development of NaI(Tl) scintillating films for imaging soft x-rays

    International Nuclear Information System (INIS)

    Shepherd, J.A.

    1993-01-01

    Thin film NaI(Tl) scintillators, of areas of up to 130 cm 2 , have been fabricated and characterized for use on soft x-ray imaging photomultiplier tubes. Relevant parameters of photon-counting imaging detectors are defined and used to predict the performance of several materials, including CsI(Na), CsI(Tl), CaF 2 (Eu), Lu 2 (SiO 4 )O:Ce, and NaI(Tl), as thin film scintillators on fiber optic substrates. Also, x-ray imaging methodologies are compared. The NaI(Tl) films were vapor-deposited onto quartz and fiber optic substrates using a powder flash deposition technique. When compared to single crystal NaI(Tl), the films were found to have equally high light yield but lower energy resolution. Light yield optimization was studied in detail including the effects of substrate temperature, activator concentration in the evaporant, and boat temperature. Spatial resolution as well as parallax errors are discussed and measured for film thicknesses up to 61 μm. A technique is described that can substantially increase the light collection of high index films on fiber optic disks. The light collection was improved by 20% by coating the disk with potassium silicate before the NaI(Tl) deposition. Large area films, up to 130 cm 2 , had a spatial uniformity of response within ±1.5% for count rate and ±3.5% for light yield, and their spatial resolution exceeded 16.6 lp mm -1 when deposited onto fiber optic substrates. The 8-keV x-ray detection efficiency of the microchannel plate imaging photomultiplier tube coupled to a NaI(Tl) film scintillator is predicted to be 88%. Other uses for the films are also described

  13. Structure and scintillation properties of CsI(Tl) films on Si single crystal substrates

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Lina [State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China, Chengdu 610054 (China); Liu, Shuang, E-mail: shuangliu@uestc.edu.cn [State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China, Chengdu 610054 (China); Chen, Dejun; Zhang, Shangjian; Liu, Yong; Zhong, Zhiyong [State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China, Chengdu 610054 (China); Falco, Charles M. [University of Arizona, College of Optical Sciences, AZ 85721 (United States)

    2016-10-30

    Highlights: • We obtained the desired micro-columnar structure of CsI(Tl) films on the orienting Si substrates. • We improved the micro-columnar structure of CsI(Tl) films under the relatively large deposition rate through using the substrate with a pre-deposited CsI nanolayer. • We modeled the interface structures between the CsI(Tl) films with (200) and (310) orientation and Si(111) substrates to explain the preferred orientation of film under the influence of the orienting substrate significantly. • We gained a new spectrum of the CsI(Tl) films peaked at 740 nm wavelength. - Abstract: CsI(Tl) scintillation films fabricated on glass substrates are widely applied for X-ray imaging because their ability to grow in micro-columnar structure and proper emission wavelength matching CCD cameras. But the coupling process between the CsI(Tl) films and Si-based photo detector would cause coupling loss. In this work, CsI(Tl) films were deposited on the orienting Si substrates and the Si substrates covered by the pre-deposited CsI nanolayers. Structure and scintillation properties of films were examined by using scanning electron microscopy, X-ray diffraction, photoluminescence and radioluminescent spectrum. The films deposited on the orienting Si substrates show the micro-columnar morphology with perfect single crystalline structure and the photoluminescence spectra with bimodal distribution. The performances of the films prepared on the pre-deposited CsI nanolayer, containing micro-columns structure and the light yield are improved.

  14. Structure and scintillation properties of CsI(Tl) films on Si single crystal substrates

    International Nuclear Information System (INIS)

    Guo, Lina; Liu, Shuang; Chen, Dejun; Zhang, Shangjian; Liu, Yong; Zhong, Zhiyong; Falco, Charles M.

    2016-01-01

    Highlights: • We obtained the desired micro-columnar structure of CsI(Tl) films on the orienting Si substrates. • We improved the micro-columnar structure of CsI(Tl) films under the relatively large deposition rate through using the substrate with a pre-deposited CsI nanolayer. • We modeled the interface structures between the CsI(Tl) films with (200) and (310) orientation and Si(111) substrates to explain the preferred orientation of film under the influence of the orienting substrate significantly. • We gained a new spectrum of the CsI(Tl) films peaked at 740 nm wavelength. - Abstract: CsI(Tl) scintillation films fabricated on glass substrates are widely applied for X-ray imaging because their ability to grow in micro-columnar structure and proper emission wavelength matching CCD cameras. But the coupling process between the CsI(Tl) films and Si-based photo detector would cause coupling loss. In this work, CsI(Tl) films were deposited on the orienting Si substrates and the Si substrates covered by the pre-deposited CsI nanolayers. Structure and scintillation properties of films were examined by using scanning electron microscopy, X-ray diffraction, photoluminescence and radioluminescent spectrum. The films deposited on the orienting Si substrates show the micro-columnar morphology with perfect single crystalline structure and the photoluminescence spectra with bimodal distribution. The performances of the films prepared on the pre-deposited CsI nanolayer, containing micro-columns structure and the light yield are improved.

  15. Particle identification in a wide dynamic range based on pulse-shape analysis with solid-state detectors

    International Nuclear Information System (INIS)

    Pausch, G.; Hilscher, D.; Ortlepp, H.G.

    1994-04-01

    Heavy ions detected in a planar silicon detector were identified by exploiting a recently proposed combination of the pulse-shape and the time-of-flight techniques. We were able to resolve charge numbers up to Z = 16 within a wide dynamic range of ∼ 1:5, and to identify even isotopes for the elements up to Magnesium. The simple scheme of signal processing is based on conventional electronics and cheap enough to be exploited in large multidetector arrays. (orig.)

  16. Detector of the reactor AntiNeutrino based on Solid-state plastic Scintillator (DANSS). Status and first results

    Czech Academy of Sciences Publication Activity Database

    Alekseev, I.; Belov, V.; Brudanin, V.; Danilov, M.; Egorov, V.; Filosofov, D. V.; Fomina, M.; Hons, Zdeněk; Kazartsev, S.; Kobyakin, A.; Machikhiliyan, I.; Medvedev, D.; Nesterov, V.; Olshevsky, A.; Ponomarev, D.; Rozova, I.; Rumyantseva, N.; Rusinov, V.; Salamatin, A.; Shevchik, Y.; Shirchenko, M.; Shitov, Yu. A.; Skrobova, N.; Starostin, A.; Svirida, D.N.; Tarkovsky, E.; Tikhomirov, I.; Vlášek, J.; Zhitnikov, I.; Zinatulina, D. R.

    2017-01-01

    Roč. 798, UNSP (2017), č. článku 012152. ISSN 1742-6588. [2nd International Conference on Particle Physics and Astrophysics (ICPPA). Moscow, 11.10.2016-14.10.2016] R&D Projects: GA MŠk LG14004 Institutional support: RVO:61389005 Keywords : detector * SiPMs * beta-decay Subject RIV: BF - Elementary Particles and High Energy Physics OBOR OECD: Particles and field physics

  17. The use of thallium diethyldithiocarbamate for mapping CNS potassium metabolism and neuronal activity: Tl+ -redistribution, Tl+ -kinetics and Tl+ -equilibrium distribution.

    Science.gov (United States)

    Wanger, Tim; Scheich, Henning; Ohl, Frank W; Goldschmidt, Jürgen

    2012-07-01

    The potassium (K(+)) analogue thallium (Tl(+)) can be used as a tracer for mapping neuronal activity. However, because of the poor blood-brain barrier (BBB) K(+) -permeability, only minute amounts of Tl(+) enter the brain after systemic injection of Tl(+) -salts like thallium acetate (TlAc). We have recently shown that it is possible to overcome this limitation by injecting animals with the lipophilic chelate complex thallium diethyldithiocarbamate (TlDDC), that crosses the BBB and releases Tl(+) prior to neuronal or glial uptake. TlDDC can thus be used for mapping CNS K(+) metabolism and neuronal activity. Here, we analyze Tl(+) -kinetics in the rodent brain both experimentally and using simple mathematical models. We systemically injected animals either with TlAc or with TlDDC. Using an autometallographic method we mapped the brain Tl(+) -distribution at various time points after injection. We show that the patterns and kinetics of Tl(+) -redistribution in the brain are essentially the same irrespective of whether animals have been injected with TlAc or TlDDC. Data from modeling and experiments indicate that transmembrane Tl(+) -fluxes in cells within the CNS in vivo equilibrate at similar rates as K(+) -fluxes in vitro. This equilibration is much faster than and largely independent of the equilibration of Tl(+) -fluxes across the BBB. The study provides further proof-of-concept for the use of TlDDC for mapping neuronal activity and CNS K(+) -metabolism. A theoretical guideline is given for the use of K(+) -analogues for imaging neuronal activity with general implications for the use of metal ions in neuroimaging. © 2012 The Authors. Journal of Neurochemistry © 2012 International Society for Neurochemistry.

  18. Detectors - Electronics

    International Nuclear Information System (INIS)

    Bregeault, J.; Gabriel, J.L.; Hierle, G.; Lebotlan, P.; Leconte, A.; Lelandais, J.; Mosrin, P.; Munsch, P.; Saur, H.; Tillier, J.

    1998-01-01

    The reports presents the main results obtained in the fields of radiation detectors and associated electronics. In the domain of X-ray gas detectors for the keV range efforts were undertaken to rise the detector efficiency. Multiple gap parallel plate chambers of different types as well as different types of X → e - converters were tested to improve the efficiency (values of 2.4% at 60 KeV were reached). In the field of scintillators a study of new crystals has been carried out (among which Lutetium orthosilicate). CdTe diode strips for obtaining X-ray imaging were studied. The complete study of a linear array of 8 CdTe pixels has been performed and certified. The results are encouraging and point to this method as a satisfying solution. Also, a large dimension programmable chamber was used to study the influence of temperature on the inorganic scintillators in an interval from -40 deg. C to +150 deg. C. Temperature effects on other detectors and electronic circuits were also investigated. In the report mentioned is also the work carried out for the realization of the DEMON neutron multidetector. For neutron halo experiments different large area Si detectors associated with solid and gas position detectors were realized. In the frame of a contract with COGEMA a systematic study of Li doped glasses was undertaken aiming at replacing with a neutron probe the 3 He counters presently utilized in pollution monitoring. An industrial prototype has been realised. Other studies were related to integrated analog chains, materials for Cherenkov detectors, scintillation probes for experiments on fundamental processes, gas position sensitive detectors, etc. In the field of associated electronics there are mentioned the works related to the multidetector INDRA, data acquisition, software gamma spectrometry, automatic gas pressure regulation in detectors, etc

  19. BES detector

    International Nuclear Information System (INIS)

    Bai, J.Z.; Bian, Q.; Chen, G.M.; Chen, L.J.; Chen, S.N.; Chen, Y.Q.; Chen, Z.Q.; Chi, Y.K.; Cui, H.C.; Cui, X.Z.; Deng, S.S.; Deng, Y.W.; Ding, H.L.; Dong, B.Z.; Dong, X.S.; Du, X.; Du, Z.Z.; Feng, C.; Feng, Z.; Fu, Z.S.; Gao, C.S.; Gao, M.L.; Gao, S.Q.; Gao, W.X.; Gao, Y.N.; Gu, S.D.; Gu, W.X.; Guan, Y.Z.; Guo, H.F.; Guo, Y.N.; Guo, Y.Y.; Han, S.W.; Han, Y.; Hao, W.; He, J.; He, K.R.; He, M.J.; Hou, X.J.; Hu, G.Y.; Hu, J.S.; Hu, J.W.; Huang, D.Q.; Huang, Y.Z.; Jia, Q.P.; Jiang, C.H.; Ju, Q.; Lai, Y.F.; Lang, P.F.; Li, D.S.; Li, F.; Li, H.; Li Jia; Li, J.T.; Li Jin; Li, L.L.; Li, P.Q.; Li, Q.M.; Li, R.B.; Li, S.Q.; Li, W.; Li, W.G.; Li, Z.X.; Liang, G.N.; Lin, F.C.; Lin, S.Z.; Lin, W.; Liu, Q.; Liu, R.G.; Liu, W.; Liu, X.; Liu, Z.A.; Liu, Z.Y.; Lu, C.G.; Lu, W.D.; Lu, Z.Y.; Lu, J.G.; Ma, D.H.; Ma, E.C.; Ma, J.M.; Mao, H.S.; Mao, Z.P.; Meng, X.C.; Ni, H.L.; Nie, J.; Nie, Z.D.; Niu, W.P.; Pan, L.J.; Qi, N.D.; Qian, J.J.; Qu, Y.H.; Que, Y.K.; Rong, G.; Ruan, T.Z.; Shao, Y.Y.; Shen, B.W.; Shen, D.L.; Shen, J.; Sheng, H.Y.; Sheng, J.P.; Shi, H.Z.; Song, X.F.; Sun, H.S.; Tang, F.K.; Tang, S.Q.; Tian, W.H.; Wang, F.; Wang, G.Y.; Wang, J.G.; Wang, J.Y.; Wang, L.S.; Wang, L.Z.; Wang, M.; Wang, P.; Wang, P.L.; Wang, S.M.; Wang, S.Q.; Wang, T.J.; Wang, X.W.; Wang, Y.Y.; Wang, Z.H.; Wang, Z.J.; Wei, C.L.; Wei, Z.Z.; Wu, J.W.; Wu, S.H.; Wu, S.Q.; Wu, W.M.; Wu, X.D.; Wu, Z.D.; Xi, D.M.; Xia, X.M.; Xiao, J.; Xie, P.P.; Xie, X.X.; Xu, J.G.; Xu, R.S.; Xu, Z.Q.; Xuan, B.C.; Xue, S.T.; Yan, J.; Yan, S.P.; Yan, W.G.; Yang, C.Z.; Yang, C.M.; Yang, C.Y.; Yang, X.F.; Yang, X.R.; Ye, M.H.; Yu, C.H.; Yu, C.S.; Yu, Z.Q.; Zhang, B.Y.; Zhang, C.D.; Zhang, C.C.; Zhang, C.Y.; Zhang, D.H.; Zhang, G.; Zhang, H.Y.; Zhang, H.L.; Zhang, J.W.; Zhang, L.S.; Zhang, S.Q.; Zhang, Y.P.; Zhang, Y.; Zhang, Y.M.; Zhao, D.X.; Zhao, J.W.; Zhao, M.; Zhao, P.D.; Zhao, P.P.; Zhao, W.R.; Zhao, Z.G.; Zhao, Z.Q.; Zheng, J.P.; Zheng, L.S.; Zheng, M.; Zheng, W.S.; Zheng, Z.P.; Zhong, G.P.; Zhou, G.P.; Zhou, H.S.; Zhou, J.; Zhou Li; Zhou Lin; Zhou, M.; Zhou, Y.S.; Zhou, Y.H.; Zhu, G.S.; Zhu, Q.M.; Zhu, S.G.; Zhu, Y.C.; Zhu, Y.S.; Zhuang, B.A.

    1994-01-01

    The Beijing Spectrometer (BES) is a general purpose solenoidal detector at the Beijing Electron Positron Collider (BEPC). It is designed to study exclusive final states in e + e - annihilations at the center of mass energy from 3.0 to 5.6 GeV. This requires large solid angle coverage combined with good charged particle momentum resolution, good particle identification and high photon detection efficiency at low energies. In this paper we describe the construction and the performance of BES detector. (orig.)

  20. Impact of precursor purity on optical properties and radiation detection of CsI:Tl scintillators

    Energy Technology Data Exchange (ETDEWEB)

    Saengkaew, Phannee; Cheewajaroen, Kulthawat; Yenchai, Chadet; Thong-aram, Decho [Chulalongkorn University, Department of Nuclear Engineering, Faculty of Engineering, Bangkok (Thailand); Sanorpim, Sakuntam [Chulalongkorn University, Department of Physics, Faculty of Science, Bangkok (Thailand); Jitpukdee, Manit [Kasetsart University, Department of Applied Radiation and Isotope, Faculty of Science, Bangkok (Thailand); Yordsri, Visittapong; Thanachayanont, Chanchana [Ministry of Science and Technology, National Metal and Materials Technology Center, National Science and Technology Development Agency, Pathumthani (Thailand); Nuntawong, Noppadon [Ministry of Science and Technology, National Electronic and Computer Technology Center, National Science and Technology Development Agency, Pathumthani (Thailand)

    2016-08-15

    Cesium iodide doped with thallium (CsI:Tl) crystals was grown to develop the gamma-ray detectors by using low-cost raw materials. Effect of impurities on optical properties and radiation detection performance was investigated. By a modified homemade Bridgman-Stockbarger technique, CsI:Tl samples were grown in two levels of CsI and TlI reactant materials, i.e., having as a very high purity of 99.999 % and a high purity of 99.9 %. XRD measurements indicate CsI:Tl crystals having a good quality with a dominant (110) plane. Having a cubic structure, a lattice constant of CsI crystals of 0.4574 nm and a crystallite size of 43.539 nm were obtained. From the lower-purity raw materials, calcite was found in an orange crystal with a lattice constant of 0.4560 nm and a crystallite size of 43.089 nm. By PL measurements, the optical properties of the CsI:Tl crystals were analyzed. ∝540-nm-wavelength PL peak was observed from the colorless high-purity crystal, and ∝600-nm-wavelength PL peak was observed from the orange crystal. The brighter PL emission was obtained from the orange crystals suggesting impurities. CsI:Tl surface morphology by SEM exhibited a smooth surface with some parallel crystal facets. For electrical properties of high-quality CsI:Tl crystals, the electrical resistances were 230 ± 16 MΩ in cross-sectional direction and 714 ± 136 MΩ in vertical direction with respect to more homogeneous crystal quality in cross-sectional direction than that in vertical direction. TEM measurement was applied to evaluate the microstructure of colorless CsI:Tl crystal with different patterns of a cubic structure. Both CsI:Tl crystals show good efficiencies and good resolutions. Maintaining the same electronic conditions and amplifications, the colorless CsI:Tl scintillators represented a higher detection efficiency at 122 keV of Co-57 of 78.4 % and the energy resolution of 23.3 % compared to the detection efficiency of 75.9 % and the energy resolution of 34.6 % of the

  1. Gamma ray energy loss spectra simulation in NaI detectors with the Monte Carlo method

    International Nuclear Information System (INIS)

    Vieira, W.J.

    1982-01-01

    With the aim of studying and applying the Monte Carlo method, a computer code was developed to calculate the pulse height spectra and detector efficiencies for gamma rays incident on NaI (Tl) crystals. The basic detector processes in NaI (Tl) detectors are given together with an outline of Monte Carlo methods and a general review of relevant published works. A detailed description of the application of Monte Carlo methods to ν-ray detection in NaI (Tl) detectors is given. Comparisons are made with published, calculated and experimental, data. (Author) [pt

  2. Ab-Initio analysis of TlBr: limiting the ionic current without degrading the electronic one

    Science.gov (United States)

    Rocha Leao, Cedric; Lordi, Vincenzo

    2011-03-01

    Although TlBr in principle presents all the theoretical requirements for making high resolution room temperature radiation detectors, practical applications of TlBr have proven to be nonviable due to the polarization that is observed in the crystal after relatively short periods of operation. This polarization, that is believed to be caused by accumulation of oppositely charged ionic species at the ends of the crystal, results in an electric field that opposes that of the applied bias, counter-acting its effect. In this work, we use state of the art quantum modeling to benchmark the theoretical limits for the performance of TlBr as a radiation detector, showing that the best experimental reports demonstrate near-ideal electronic characteristics. We then propose a model to inhibit the detrimental ionic current in the material without impacting the excellent properties of the electronic current. Prepared by LLNL under Contract DE-AC52-07NA27344.

  3. A new method for studying the transport of radon and thoron in various building materials using CR-39 and LR-115 solid state nuclear track detectors

    International Nuclear Information System (INIS)

    Misdaq, M.A.; Ktata, A.; Bakhchi, A.

    2000-01-01

    Radon ( 222 Rn) and thoron ( 220 Rn) α-activities per unit volume were measured inside and outside different building materials by using two types of solid state nuclear track detectors (SSNTD) (CR-39 and LR-115 type II). In addition, the radon and thoron emanation coefficients of the studied materials were evaluated. Based on these data, the transport of radon and thoron across parallelepipedic blocks of the building materials could be investigated and radon and thoron global α-activities per unit volume outside different building material blocks were determined. Moreover, the diffusion length and the effective diffusion coefficient of radon in the building materials were evaluated and the total alpha activity due to radon in the atmospheres of different rooms consisting of different building materials was studied

  4. Validation and application of the methodology for analysis of radon concentration in the air through the technique of solid state nuclear track detectors (SSNTD)

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, Caroline de [Pontificia Universidade Catolica de Minas Gerais (PUC-Pocos), Pocos de Caldas, MG (Brazil); Comissao Nacional de Energia Nuclear (LAPOC/CNEN), Pocos de Caldas, MG (Brazil). Lab. de Pocos de Caldas; Silva, Nivaldo Carlos da, E-mail: ncsilva@cnen.gov.b [Comissao Nacional de Energia Nuclear (LAPOC/CNEN), Pocos de Caldas, MG (Brazil). Lab. de Pocos de Caldas

    2011-07-01

    Radon is a radioactive noble gas that occurs naturally in soil and could enter into residential. The decay products of radon are radioactive metals which, when inhaled, can be retained in the respiratory system, leading to an internal dose of radiation. The monitoring of radon levels in residences and workplaces is extremely important, since high concentrations of this gas can cause serious public health problems. This study analyzed the concentration of radon in the air in 94 work environments at the Laboratory of Pocos de Caldas - LAPOC/CNEN, including laboratories, administrative rooms, workshop, warehouse and guardhouse. The method employed in the monitoring was the technique of solid state nuclear track detectors, known as SSNTD. For calibration and validation of this method, controlled experiments were conducted in laboratory with specific instrumentation. The monitoring results indicated that most environments present radon concentrations above 100 Bq m{sup -3}, which is the reference level recommended by the World Health Organization. (author)

  5. Validation and application of the methodology for analysis of radon concentration in the air through the technique of solid state nuclear track detectors (SSNTD)

    International Nuclear Information System (INIS)

    Carvalho, Caroline de; Comissao Nacional de Energia Nuclear; Silva, Nivaldo Carlos da

    2011-01-01

    Radon is a radioactive noble gas that occurs naturally in soil and could enter into residential. The decay products of radon are radioactive metals which, when inhaled, can be retained in the respiratory system, leading to an internal dose of radiation. The monitoring of radon levels in residences and workplaces is extremely important, since high concentrations of this gas can cause serious public health problems. This study analyzed the concentration of radon in the air in 94 work environments at the Laboratory of Pocos de Caldas - LAPOC/CNEN, including laboratories, administrative rooms, workshop, warehouse and guardhouse. The method employed in the monitoring was the technique of solid state nuclear track detectors, known as SSNTD. For calibration and validation of this method, controlled experiments were conducted in laboratory with specific instrumentation. The monitoring results indicated that most environments present radon concentrations above 100 Bq m -3 , which is the reference level recommended by the World Health Organization. (author)

  6. The cosmic ray actinide charge spectrum derived from a 10 m{sup 2} array of solid state nuclear track detectors in Earth orbit

    Energy Technology Data Exchange (ETDEWEB)

    Donnelly, J. E-mail: jd@cp.dias.ie; Thompson, A.; O' Sullivan, D.; Drury, L.O' C.; Wenzel, K.-P

    2001-06-01

    The DIAS-ESTEC Ultra Heavy Cosmic Ray Experiment (UHCRE) on the Long Duration Exposure Facility, collected approximately 3000 cosmic ray nuclei with Z>65 in the energy region E>1.5 GeV nucleon{sup -1} during a six year exposure in Earth orbit. The entire accessible collecting area of the solid state nuclear track detector (SSNTD) array has been scanned for actinides, yielding a sample of 30 from an exposure of {approx}150 m{sup 2} sr yr. The UHCRE experimental setup is described and the observed charge spectrum presented. The current best value for the cosmic ray actinide relative abundance, (Z>88)/(74{<=}Z{<=}87), is reported.

  7. Influence of Impurities on the Radiation Response of the TlBr Semiconductor Crystal

    Directory of Open Access Journals (Sweden)

    Robinson Alves dos Santos

    2017-01-01

    Full Text Available Two commercially available TlBr salts were used as the raw material for crystal growths to be used as radiation detectors. Previously, TlBr salts were purified once, twice, and three times by the repeated Bridgman method. The purification efficiency was evaluated by inductively coupled plasma mass spectroscopy (ICP-MS, after each purification process. A compartmental model was proposed to fit the impurity concentration as a function of the repetition number of the Bridgman growths, as well as determine the segregation coefficients of impurities in the crystals. The crystalline structure, the stoichiometry, and the surface morphology of the crystals were evaluated, systematically, for the crystals grown with different purification numbers. To evaluate the crystal as a radiation semiconductor detector, measurements of its resistivity and gamma-ray spectroscopy were carried out, using 241Am and 133Ba sources. A significant improvement of the radiation response was observed in function of the crystal purity.

  8. Contribution to the study of radon risk assessment - Use of Solid State Nuclear Tracks Detectors (SSNTD) for the measurement of radon in buildings

    International Nuclear Information System (INIS)

    RALAIARISOA, H.L

    2004-01-01

    222 Rn is a natural radioactive gas, originating from the decay of 226 Ra. Both of these radionuclides are elements of 238 U series. Uranium is naturally present in the rocks and soils, therefore radon is always present too because it is a soil gas. Radon takes the most important part in man exposure to natural sources of ionizing radiations. Moreover, it causes lung cancer. It can accumulate in confined environments such as buildings, so that its inhalation is a potential risk for human health. Thus radon measurement is necessary for radiation protection. Integrated measurement using Solid State Nuclear Tracks Detector (SSNTD) is a very common method for radon measurement in buildings because of the low cost of the detectors and their easy application. The measurement technics are based on the interaction of alpha particles emitted by radon with a polymer. Alpha particles produce in the polymer latent tracks, which need chemical revelation to be observable with optical microscopy. The number of revealed tracks is proportionnal to the average volumic activity of 222 Rn corresponding to the time exposure of the detectors.The aim of this thesis work is the continuation of previous study on the preliminary investigations of radon levels in the city of Antananarivo, and to extend this study in Antsirabe, which has been shown as a region of interest. The levels of radon measured in buildings in Antananarivo and Antsirabe are typical values of indoor radon concentration. The average values of concentrations are inferior to 60 Bq.m - 3. The health risk is negligible but not nul. A typical protocol of radon level measurement in Malagasy buildings is suggested to allow the implementation of a risk management policy related to radon within the Malagasy context. [fr

  9. A new type of spurious reading in TL personnel monitoring

    International Nuclear Information System (INIS)

    Duftschmid, K.E.; Stadtmann, H.; Strachotinsky, Ch.; Winker, N.

    1996-01-01

    A particularly serious type of spurious reading in automated TL personnel monitoring has been observed. These readings simulate dose values up to several mSv and can only be detected by glow curve analysis. Characteristics for these events are high artifical dose values and irregular glow curves of a particular shape. Extensive investigations to reproduce this effect purposely failed to produce any results. It can be assumed, however, that it must be some chemical surface contamination, which penetrates the sealed dosemeter bag or which is transferred from the bag to the detector. The effect can be eliminated by manual cleaning of the dosemeter cards. The importance of this observation lies in the fact that only proper glow curve evaluation can prevent the monitoring service from reporting artificial high dose readings creating lots of serious problems. The paper shows how this problem can be avoided for this kind of spurious effect, if glow curves are available and stored for every dosemeter readout. (author)

  10. Frontier detectors for frontier physics

    International Nuclear Information System (INIS)

    Cervelli, F.; Scribano, A.

    1984-01-01

    These proceedings contain the articles presented at the named meeting. These concern developments of radiation detectors and counting techniques in high energy physics. Especially considered are tracking detectors, calorimeters, time projection chambers, detectors for rare events, solid state detectors, particle identification, and optical readout systems. See hints under the relevant topics. (HSI)

  11. Direct and precise determination of environmental radionuclides in solid materials using a modified Marinelli beaker and a HPGe detector

    International Nuclear Information System (INIS)

    Seo, B.K.; Lee, D.W.; Lee, K.Y.; Yoon, Y.Y.

    2001-01-01

    A simple but precise detection method was studied for the determination of natural radionuclides using a conventional HPGe detector. A new aluminium beaker instead of a plastic Marinelli beaker was constructed and examined to reach radioactive equilibrium conditions between radon and its daughter elements without the escape of gaseous radon. Using this beaker fifteen natural radionuclides from three natural decay series could be determined by direct γ-ray measurement and sixteen radionuclides could be determined indirectly after radioactive equilibrium had been reached. Analytical results from ground water were compared with those from conventional α spectroscopy and the results agreed well within 12% difference. Nitrogen gas purge was used to replace the surrounding air of the detector to obtain a stable background and reducing the interference of radon daughter nuclides in the atmosphere. The use of nitrogen purging and the aluminium Marinelli beaker results in an approximately tenfold increase of sensitivity and a decrease of the detection limit of 226 Ra to about 0.74 Bq kg -1 in soil samples. (orig.)

  12. Direct and precise determination of environmental radionuclides in solid materials using a modified Marinelli beaker and a HPGe detector.

    Science.gov (United States)

    Seo, B K; Lee, K Y; Yoon, Y Y; Lee, D W

    2001-06-01

    A simple but precise detection method was studied for the determination of natural radionuclides using a conventional HPGe detector. A new aluminium beaker instead of a plastic Marinelli beaker was constructed and examined to reach radioactive equilibrium conditions between radon and its daughter elements without the escape of gaseous radon. Using this beaker fifteen natural radionuclides from three natural decay series could be determined by direct gamma-ray measurement and sixteen radionuclides could be determined indirectly after radioactive equilibrium had been reached. Analytical results from ground water were compared with those from conventional alpha spectroscopy and the results agreed well within 12% difference. Nitrogen gas purge was used to replace the surrounding air of the detector to obtain a stable background and reducing the interference of radon daughter nuclides in the atmosphere. The use of nitrogen purging and the aluminium Marinelli beaker results in an approximately tenfold increase of sensitivity and a decrease of the detection limit of 226Ra to about 0.74 Bq kg(-1) in soil samples.

  13. Cherenkov light imaging tests with state-of-the-art solid state photon counter for the CLAS12 RICH detector

    Science.gov (United States)

    Balossino, Ilaria; Barion, L.; Contalbrigo, M.; Lenisa, P.; Lucherini, V.; Malaguti, R.; Mirazita, M.; Movsisyan, A.; Squerzanti, S.; Turisini, M.

    2017-12-01

    A large area ring-imaging Cherenkov detector will be operated for hadron identification in the 3 GeV / c to 8 GeV / c momentum range at the CLAS12 experiment at the upgraded continuous electron beam accelerator facility of Jefferson Lab. The detector, consisting of aerogel radiator, composite mirrors and photon counters, will be built with a hybrid optics design to allow the detection of Cherenkov light for both forward and large angle hadron tracks. The active area has to be densely packed and highly segmented, covering about 1m2 with pixels of 6mm2 , and to allow a time resolution of 1 ns. A technology that can offer a cost-effective solution and low material budget could be Silicon Photomultipliers (SiPM) thanks to their high gain at low bias voltage, fast timing, good single-photoelectron resolution and insensitivity to magnetic fields. An investigation is ongoing on samples of 3 × 3mm2 SiPM of different micro-cell size to assess the single photon detection capability in the presence of high dark count rate due to thermal generation effects, after-pulses or optical cross-talk and to study the response to the moderate radiation damage expected at CLAS12. In this work, a brief review of the latest and most interesting results from these studies will be shown.

  14. Solid state nuclear track detectors in the measurement of alpha to fission branching ratios of heavy actinides

    International Nuclear Information System (INIS)

    Pandey, A.K.; Sharma, R.C.; Padalkar, S.K.; Kalsi, P.C.; Iyer, R.H.

    1992-01-01

    A sequential etching procedure for revelation of alpha and fission tracks in CR-39 was developed and optimized. Using this technique alpha and fission tracks can be differentiated unambiguously because of significant differences in their sizes and etching times. This registration and revelation procedure for alpha and fission tracks may be used for the studies of half lives, alpha to fission branching ratios and identification of radionuclides based on their decay schemes. It has the added advantage that both alpha decay and fission events can be studied using one detector and hence uncertainties related to efficiency, registration geometry, registration times, amount of radionuclides etc can be eliminated or minimized. The effects of neutron, gamma and alpha radiations on the alpha and fission fragment tracks registration and revelation properties of CR-39 detectors [CR-39, CR-39 (DOP)] were also studied. The IR spectra were also studied to find out the nature of chemical changes produced by these radiations on CR-39. (author). 32 refs., 7 figs., 4 tabs

  15. Simulation of the peak efficiency for a stacked NaI(Tl) spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, H; Murohka, H; Anami, K; Nohtomi, A; Uozumi, Y; Sakae, T; Matoba, M [Kyushu Univ., Fukuoka (Japan). Faculty of Engineering; Koori, N; Maki, T

    1996-07-01

    A stacked NaI(Tl) spectrometer has been developed to measure proton spectra in wide energy range. In the measurement of charged particles with intermediate energy, the detecting efficiency of the spectrometer decreases considerably due to nuclear reactions or out-scattering in the detector material. A Monte Carlo simulation code has been developed to estimate the peak efficiency (peak-to-total ratio) of the spectrometer. The calculated efficiency for intermediate energy is in good agreement with the experimental one. (author)

  16. Thermodynamic Study of Tl6SBr4 Compound and Some Regularities in Thermodynamic Properties of Thallium Chalcohalides

    Directory of Open Access Journals (Sweden)

    Dunya Mahammad Babanly

    2017-01-01

    Full Text Available The solid-phase diagram of the Tl-TlBr-S system was clarified and the fundamental thermodynamic properties of Tl6SBr4 compound were studied on the basis of electromotive force (EMF measurements of concentration cells relative to a thallium electrode. The EMF results were used to calculate the relative partial thermodynamic functions of thallium in alloys and the standard integral thermodynamic functions (-ΔfG0, -ΔfH0, and S0298 of Tl6SBr4 compound. All data regarding thermodynamic properties of thallium chalcogen-halides are generalized and comparatively analyzed. Consequently, certain regularities between thermodynamic functions of thallium chalcogen-halides and their binary constituents as well as degree of ionization (DI of chemical bonding were revealed.

  17. A theoretical study of CsI:Tl columnar scintillator image quality parameters by analytical modeling

    Energy Technology Data Exchange (ETDEWEB)

    Kalyvas, N., E-mail: nkalyvas@teiath.gr; Valais, I.; Michail, C.; Fountos, G.; Kandarakis, I.; Cavouras, D.

    2015-04-11

    Medical X-ray digital imaging systems such as mammography, radiography and computed tomography (CT), are composed from efficient radiation detectors, which can transform the X-rays to electron signal. Scintillators are materials that emit light when excited by X-rays and incorporated in X-ray medical imaging detectors. Columnar scintillator, like CsI:T1 is very often used for X-ray detection due to its higher performance. The columnar form limits the lateral spread of the optical photons to the scintillator output, thus it demonstrates superior spatial resolution compared to granular scintillators. The aim of this work is to provide an analytical model for calculating the MTF, the DQE and the emission efficiency of a columnar scintillator. The model parameters were validated against published Monte Carlo data. The model was able to predict the overall performance of CsI:Tl scintillators and suggested an optimum thickness of 300 μm for radiography applications. - Highlights: • An analytical model for calculating MTF, DQE and Detector Optical Gain (DOG) of columnar phosphors was developed. • The model was fitted to published efficiency and MTF Monte Carlo data. • A good fit was observed for 300 µm columnar CsI:Tl thickness. • The performance of the 300 µm column thickness CsI:Tl was better in terms of MTF and DOG for radiographic applications.

  18. Accidental and retrospective dosimetry using TL method

    International Nuclear Information System (INIS)

    Mesterházy, D.; Osvay, M.; Kovács, A.; Kelemen, A.

    2012-01-01

    Retrospective dosimetry is one of the most important tools of accidental dosimetry for dose estimation when dose measurement was not planned. In the affected area many objects can be applied as natural dosimeters. The paper discusses our recent investigations on various electronic components and common salt (NaCl) having useful thermoluminescence (TL) properties. Among materials investigated the electronic components of cell phones seem promising for retrospective dosimetry purposes, having high TL responses, proper glow curve peaks and the intensity of TL peaks vs. gamma dose received provided nearly linear response in the dose range of 10 mGy–1.5 Gy. - Highlights: ► Electronic components and common salt were investigated for accidental and retrospective dosimetry. ► SMD resistors seem promising for retrospective dosimetry purposes. ► Table salt can be used effectively for accidental dosimetry purposes, as well.

  19. Detailed α -decay study of 180Tl

    Science.gov (United States)

    Andel, B.; Andreyev, A. N.; Antalic, S.; Barzakh, A.; Bree, N.; Cocolios, T. E.; Comas, V. F.; Diriken, J.; Elseviers, J.; Fedorov, D. V.; Fedosseev, V. N.; Franchoo, S.; Ghys, L.; Heredia, J. A.; Huyse, M.; Ivanov, O.; Köster, U.; Liberati, V.; Marsh, B. A.; Nishio, K.; Page, R. D.; Patronis, N.; Seliverstov, M. D.; Tsekhanovich, I.; Van den Bergh, P.; Van De Walle, J.; Van Duppen, P.; Venhart, M.; Vermote, S.; Veselský, M.; Wagemans, C.

    2017-11-01

    A detailed α -decay spectroscopy study of 180Tl has been performed at ISOLDE (CERN). Z -selective ionization by the Resonance Ionization Laser Ion Source (RILIS) coupled to mass separation provided a high-purity beam of 180Tl. Fine-structure α decays to excited levels in the daughter 176Au were identified and an α -decay scheme of 180Tl was constructed based on an analysis of α -γ and α -γ -γ coincidences. Multipolarities of several γ -ray transitions deexciting levels in 176Au were determined. Based on the analysis of reduced α -decay widths, it was found that all α decays are hindered, which signifies a change of configuration between the parent and all daughter states.

  20. Determining of the track parameters in solid state nuclear track detectors Cr 39 due to alpha particles

    International Nuclear Information System (INIS)

    Kostic, D.; Nikezic, D.

    1997-01-01

    An equation of the etch pit wall is proposed to be used for simulation of the track growth and calculating the major and the minor axis of etch pit opening. Dependence on the following parameters is set up: distance along a track from the point where the particle entered the detector, ratio of the track etch wall to the bulk etch rate, integration constant determined from particle penetration depth and normal distance from the particle trajectory to the etch pit wall. The corresponding computer program was written. The input parameters of this program are: alpha particles energy, incidence angle and removed layer; the output gives track parameters. The results obtained by this method are compared to another approach given by Somogy and Szalay (1973) and a reasonably good agreement is found. (author)

  1. Evaluation of Differences in Response of DOD Portable Instruments and Solid-State Detectors used by MEXT for Measurement of External Radiations with Attention to the Cosmic Radiation Component

    Science.gov (United States)

    2014-03-01

    Defense Threat Reduction Agency 8725 John J. Kingman Road, MS-6201 Fort Belvoir, VA 22060-6201...Attention to the Cosmic Radiation Component DISTRIBUTION A. Approved for public release: distribution is unlimited March 2014...Portable Instruments and Solid-State Detectors used by MEXT for Measurement of External Radiations with Attention to the Cosmic Radiation Component 5a

  2. Estimation of track registration efficiency in solution medium and study of gamma irradiation effects on the bulk-etch rate and the activation energy for bulk etching of CR-39 (DOP) Solid State Nuclear Track Detector

    International Nuclear Information System (INIS)

    Kalsi, P.C.

    2010-01-01

    The fission track registration efficiency of diethylene glycol bis allyl carbonate (dioctyl phthalate doped) (CR-39 (DOP)) solid state nuclear track detector (SSNTD) in solution medium (K wet ) has been experimentally determined and is found to be (9.7 ± 0.5).10 -4 cm. This is in good agreement with the values of other SSNTDs. The gamma irradiation effects in the dose range of 50.0-220.0 kGy on the bulk etch rate, V b and the activation energy for bulk etching, E of this solid state nuclear track detector (SSNTD) have also been studied. It is observed that the bulk etch rates increase and the activation energies for bulk etching decrease with the increase in gamma dose. These results have been explained on the basis of scission of the detector due to gamma irradiation

  3. Real-time in-situ monitoring of the topotactic transformation of TlCu3Se2 into TlCu2Se2

    International Nuclear Information System (INIS)

    Ångström, J.; Sahlberg, M.; Berger, R.

    2015-01-01

    Highlights: • Topotactic transition from TlCu 3 Se 2 to TlCu 2 Se 2 followed in situ. • Synchrotron radiation X-ray powder diffraction enabled short scans. • Relative abundance of phases refined from powder data. • Opens up for studying similar systems in the same manner. - Abstract: The solid state transformation of monoclinic TlCu 3 Se 2 into tetragonal TlCu 2 Se 2 by oxidative copper leaching in concentrated ammonia solution has been studied in situ by the use of synchrotron radiation. The diffraction patterns of parent and daughter phase are both sharp, indicating a strong topotactic relationship between them that effectuates a rapid change by “chimie douce” performed at +19 °C. The transformation rate is strongly connected to the access of oxygen from the surrounding air. The transformation was followed in a real-time mode, being almost complete after 2.5 h with 1 h incubation due to low oxygen content, as shown from refining the diffraction patterns by Rietveld profile technique

  4. Contribution to the study of radio toxicity of aromatic and medicinal plants using solid state nuclear track detectors; Contribution a l etude de la radio toxicite des plantes aromatiques et medicinales au moyen des detecteurs solides de traces nucleaires

    Energy Technology Data Exchange (ETDEWEB)

    Mortassim, A; Misdaq, M A; Naaman, A

    2009-07-01

    The concentrations of uranium (238 U), thorium (232 Th), radon (222 Rn) and thoron (220 Rn) were measured in twenty aromatic and medicinal plants in {sup f}ind a new method based on using solid state nuclear track detectors type Cr-39 and Rs-115. He emerges from this study that the verbena and salvia have higher levels of uranium (radon) higher than that of other plants while the leaves of olive and saturja have concentrations of thorium (thoron) higher than other plants therefore radio toxicity of these plants is higher than that of others and may pose a radiological hazard if the masses are incorporated by consumers high. [French] Les concentrations en uranium (238U), thorium (232Th), radon (222Rn), et thoron (220Rn) ont ete mesurees dans vingt plantes aromatiques et medicinales en utilsant une nouvelle methode basee sur l utilisation des detecteurs solides de traces nucleaires de types CR-39 et LR-115. Il en sort de cette etude que la verveine et la salvia presentent des teneurs en uranium (radon) superieurs a celle des autres plantes alors que les feuilles d olivier et la saturja presentent des concentrations en thorium (thoron) plus elevee que celles des autres plantes par consequent la radio toxicite de ces plantes est superieure a celles des autres et peuvent presenter un risque radiologique si les masses incorporees par les consommateurs sont elevees.

  5. State of the art of solid state dosimetry; Estado da arte em dosimetria do estado solido

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Susana O., E-mail: sosouza@ufs.br [Universidade Federal de Sergipe (UFS), Sao Cristovao, SE (Brazil); Yamamoto, Takayoshi [Radioisotope Research Center, Osaka University (Japan); D' Errico, Francesco, E-mail: francesco.derrico@yale.edu [Yale University, School of Medicine, CT (United States)

    2014-07-01

    Passive solid-state detectors still dominate the personal dosimetry field. This article provides state of the art in this field and summarizes the most recent works presented on TL, OSL and RPL during the 17th International Conference on Solid State Dosimetry held in Recife in September 2013. The Article contains in particular the techniques Thermoluminescence (TL), Optically Stimulated Luminescence (OSL), radio photoluminescence (RPL). Thermoluminescence has the biggest advantage of the wide availability of commercial materials for dosimetry, and the nature tissue-equivalent of several of these materials. The limitation of the TL dosimetry presents fading luminance signal and the need for high temperatures to obtain the signal. The Optically Stimulated Luminescence has the advantages of high sensitivity, the possibility of multiple reading, while its limit is the need to use response compensating filters in addition to the high cost of equipment and dosimeters still restricted very few options trading . The radio photoluminescence has a reading that is completely non-destructive, but their dosimeters present lack of tissue-equivalent and a high cost. Presents the details of the techniques and the advantages and limitations of each of these will be discussed.

  6. Calculated Absolute Detection Efficiencies of Cylindrical Nal (Tl) Scintillation Crystals for Aqueous Spherical Sources

    Energy Technology Data Exchange (ETDEWEB)

    Strindehag, O; Tollander, B

    1968-08-15

    Calculated values of the absolute total detection efficiencies of cylindrical scintillation crystals viewing spherical sources of various sizes are presented. The calculation is carried out for 2 x 2 inch and 3 x 3 inch Nal(Tl) crystals and for sources which have the radii 1/4, 1/2, 3/4 and 1 times the crystal radius. Source-detector distances of 5-20 cm and gamma energies in the range 0.1 - 5 MeV are considered. The correction factor for absorption in the sample container wall and in the detector housing is derived and calculated for a practical case.

  7. Improved spectrometric characteristics of thallium bromide nuclear radiation detectors

    CERN Document Server

    Hitomi, K; Shoji, T; Suehiro, T; Hiratate, Y

    1999-01-01

    Thallium bromide (TlBr) is a compound semiconductor with a high atomic number and wide band gap. In this study, nuclear radiation detectors have been fabricated from the TlBr crystals. The TlBr crystals were grown by the horizontal travelling molten zone (TMZ) method using the materials purified by many pass zone refining. The crystals were characterized by measuring the resistivity, the mobility-lifetime (mu tau) product and the energy required to create an electron-hole pair (the epsilon value). Improved energy resolution has been obtained by the TlBr radiation detectors. At room temperature the full-width at half-maximum (FWHM) for the 59.5, 122 and 662 keV gamma-ray photo peak obtained from the detectors were 3.3, 8.8 and 29.5 keV, respectively. By comparing the saturated peak position of the TlBr detector with that of the CdTe detector, the epsilon value has been estimated to be about 5.85 eV for the TlBr crystal.

  8. Theoretical and experimental studies of the efficiency of a solid-state track detector utilizing (neutron, alpha) reactions

    International Nuclear Information System (INIS)

    Palfalvi, J.

    1983-04-01

    The neutron sensitivity of Kodak-Pathe LR 115 II type cellulose nitrate track detectors with different (n,α) radiators was investigated by calculations and measurements. The α counting efficiency using an optical microscope is 95% for α particles with maximum energy of 2 MeV. When using an image analyzer the etched through-tracks (holes) with diameters greater than 2 μm are counted. The efficiency then depends only on the original and removed layer thickness but not on the etching temperature within the range of 40 to 60 deg C and the 2.5 to 6 N normality of the NaOH etchant. Efficiency varies from about 3 to 20% for alphas from the 6 Li/n, +a/T reaction if the removed layer lies in the range of 7 to 10 μm, and varies from 2 to 10% for 10 B/n, α/ 7 Li reaction alphas when the layer re--moval is 8 to 10 μm. (author)

  9. Radon measurement by Solid States Nuclear Tracks Detectors (SSNTD/LR-115) in the city of Cocody (Abidjan)

    International Nuclear Information System (INIS)

    Agba, Dabo Salif Ignace

    2011-02-01

    Radon as natural gas is permanently present in our environment. It is the main natural radiological exposure source for human beings. So, the study of the concentration of this rare gas is essential in order to evaluate the risks incured by the population and the environment. The results of different studies will guide as to take the appropriate protection decisions as recommended by the World Health Organization (WHO). The present work consists in measuring the concentration of radon (Rn 222 isotope) in seven (7) pre-selected sites in the city of Cocody (Abidjan) using SSNTD/LR-115 (photographic film detectors). Our measurements showed some variations in the concentration of radon according to seasons and the influence of main factors such as the porosity, humidity and the diameter of the specks of soil. We noticed that our measured values remain very low compared to international standards. This work is the first step for more important measurements throughout the whole ivorian territory. The aim is to draw a national cartography of radon in Cote d'Ivoire. [fr

  10. The X-ray response of TlBr

    International Nuclear Information System (INIS)

    Owens, Alan; Bavdaz, M.; Brammertz, G.; Gostilo, V.; Graafsma, H.; Kozorezov, A.; Krumrey, M.; Lisjutin, I.; Peacock, A.; Puig, A.; Sipila, H.; Zatoloka, S.

    2003-01-01

    We present the results of a series of X-ray measurements on several prototype TlBr detectors. The devices were fabricated from mono-crystalline material and were typically of size 2.7x2.7x0.8 mm 3 . The material is extremely pure, having impurity concentrations -4 and 1x10 -5 cm 2 V -1 , respectively, which are about an order of magnitude higher than previously reported values. Three detectors were fabricated and extensively tested over the energy range 2.3-100 keV at three synchrotron radiation facilities: the Physikalisch-Technische Bundesanstalt (PTB) laboratory at the Berliner Elektronenspeicherring fuer Synchrotronstrahlung (BESSY II), the European Synchrotron Radiation Research Facility (ESRF) and the Hamburger Synchrotron-strahlungslabor (HASYLAB) radiation facility. Room temperature energy resolutions under full-area illumination of 1.8 and 3.3 keV FWHM have been achieved at 5.9 and 59.95 keV, respectively. At reduced detector temperatures of -30 deg. C, these fall to 800 eV and 2.6 keV FWHM, respectively. Under monochromatic pencil beam illumination, the measured energy resolutions at 6 and 60 keV were 664 eV and ∼3 keV FWHM at the same temperature. For energies 2 , 12 keV mono-energetic X-ray beam, raster scanned over the forward active area. Whilst two detectors were spatially uniform to a level commensurate with statistics, the third was not. In all cases, evidence was found for charge collection problems caused by field fringing

  11. Brain SPECT with Tl-201 DDC

    International Nuclear Information System (INIS)

    Bruine, J.F. de.

    1988-01-01

    The development, animal and human experiments and the first clinical results of a new blood flow tracer thallium-201 diethyldithiocarbamate (Tl-201 DDC) are discussed for functional brain imaging with single-photon emission computed tomography (SPECT). 325 refs.; 43 figs.; 22 tabs

  12. (Tl, Sb) and (Tl, Bi) binary surface reconstructions on Ge(111) substrate

    Science.gov (United States)

    Gruznev, D. V.; Bondarenko, L. V.; Tupchaya, A. Y.; Yakovlev, A. A.; Mihalyuk, A. N.; Zotov, A. V.; Saranin, A. A.

    2018-03-01

    2D compounds made of Group-III and Group-V elements on the surface of silicon and germanium attract considerable attention due to prospects of creating III-V binary monolayers, which are predicted to hold advanced physical properties. In the present work, we have investigated two such systems, (Tl, Sb)/Ge(111) and (Tl, Bi)/Ge(111) using scanning tunneling microscopy, low energy electron diffraction observations and density-functional-theory calculations. In addition to the previously reported surface structures of 2D (Tl, Sb) and (Tl, Bi) compounds on Si(111), we found new ones, namely, √{ 7} × √{ 7} and 3 × 3. Formation processes and plausible models of their atomic arrangements are discussed.

  13. Phantom evaluation of a cardiac SPECT/VCT system that uses a common set of solid-state detectors for both emission and transmission scans.

    Science.gov (United States)

    Bai, Chuanyong; Conwell, Richard; Kindem, Joel; Babla, Hetal; Gurley, Mike; De Los Santos, Romer; Old, Rex; Weatherhead, Randy; Arram, Samia; Maddahi, Jamshid

    2010-06-01

    We developed a cardiac SPECT system (X-ACT) with low dose volume CT transmission-based attenuation correction (AC). Three solid-state detectors are configured to form a triple-head system for emission scans and reconfigured to form a 69-cm field-of-view detector arc for transmission scans. A near mono-energetic transmission line source is produced from the collimated fluorescence x-ray emitted from a lead target when the target is illuminated by a narrow polychromatic x-ray beam from an x-ray tube. Transmission scans can be completed in 1 min with insignificant patient dose (deep dose equivalent used phantom studies to evaluate (1) the accuracy of the reconstructed attenuation maps, (2) the effect of AC on image uniformity, and (3) the effect of AC on defect contrast (DC). The phantoms we used included an ACR phantom, an anthropomorphic phantom with a uniform cardiac insert, and an anthropomorphic phantom with two defects in the cardiac insert. The reconstructed attenuation coefficient of water at 140 keV was .150 +/- .003/cm in the uniform region of the ACR phantom, .151 +/- .003/cm and .151 +/- .002/cm in the liver and cardiac regions of the anthropomorphic phantom. The ACR phantom images with AC showed correction of the bowing effect due to attenuation in the images without AC (NC). The 17-segment scores of the images of the uniform cardiac insert were 78.3 +/- 6.5 before and 87.9 +/- 3.3 after AC (average +/- standard deviation). The inferior-to-anterior wall ratio and the septal-to-lateral wall ratio were .99 and 1.16 before and 1.02 and 1.00 after AC. The DC of the two defects was .528 and .156 before and .628 and .173 after AC. The X-ACT system generated accurate attenuation maps with 1-minute transmission scans. AC improved image quality and uniformity over NC.

  14. Factors which define the α/γ ratio in CsI:Tl crystals

    International Nuclear Information System (INIS)

    Kudin, Alexander M.; Sysoeva, Elena P.; Sysoeva, Elena V.; Trefilova, Larisa N.; Zosim, Dmitry I.

    2005-01-01

    Dependences of light yield and α/γ ratio on the Tl concentration have been studied within a wide range of shaping times. It is shown that the α/γ ratio essentially depends on the Tl concentration. Proper combination of the Tl concentration and optimum shaping time in electronics allows to obtain detectors with rather high light output for γ-rays, α-particles and α/γ ratio values. It has been shown that both the light yield at α-excitation and the α/γ-ratio depend on the time of crystal storage after polishing. On the basis of the idea of the formation of deformation-induced point defects in a thin surface-adjacent layer, the causes of the temporary increasing in light yield for α-particle are explained. An explanation is given of the results obtained by Gwin and Murray concerning the fact that the α/γ ratio is practically independent on Tl concentration

  15. Study of 207Tl126 Produced in Deep-Inelastic Reactions

    Directory of Open Access Journals (Sweden)

    Wilson E.

    2014-03-01

    Full Text Available Deep-inelastic collisions of a 208Pb beam on a 208Pb target were performed using the ATLAS accelerator at Argonne National Laboratory. The Gammasphere detector array was used for the detection of prompt and delayed gamma-rays of the reaction products.207Tl is one proton away from the 208Pb doubly-magic nucleus. Its low-energy level structure is dominated by the single proton-hole states πs1/2−1, πd3/2−1 and πh11/2−1. The 11/2− state is isomeric with T1/2 = 1.33(11 s. The reaction partner of 207Tl is 209Bi, which has arelatively well established level scheme compared to 207Tl. Cross-coincidences between these two nuclei were used to confirm or establish levels above the 11/2− isomeric state in 207Tl. These states are obtained via breaking of the neutron core. Angular correlation analysis was performed on known transitions in 208Pb, proving the applicability of this method for multipolarity assignment.

  16. Principles of Good Practice in SoTL

    Science.gov (United States)

    Felten, Peter

    2013-01-01

    For the Scholarship of Teaching and Learning (SoTL) to be understood as significant intellectual work in the academy, SoTL practitioners need to identify shared principles of good practice. While honoring the diversity of SoTL in its many forms across the globe, such principles can serve as a heuristic for assessing work in our field. These…

  17. Developments on RICH detectors

    International Nuclear Information System (INIS)

    Besson, P.; Bourgeois, P.

    1996-01-01

    The RICH (ring imaging Cherenkov) detector which is dedicated to Cherenkov radiation detection is described. An improvement made by replacing photo sensible vapor with solid photocathode is studied. A RICH detector prototype with a CsI photocathode has been built in Saclay and used with Saturne. The first results are presented. (A.C.)

  18. Activation analysis of thallium in urine using the 203Tl(n,2n) 202Tl reaction

    International Nuclear Information System (INIS)

    Korob, R.O.; Cohen, I.M.; Lage, M.; Baro, G.B.

    1976-04-01

    The method developed by the authors of thallium determination in human urine, based on the 203 Tl(n,2n) 202 Tl reaction followed by chemical separation and measurement of the produced 202 Tl by gamma spectrometry, is described. Its application in some cases of intoxication by thallium is reported. The advantages and limitations of the described technique are discussed. (author) [es

  19. A study of the thermoluminescent properties of CVD diamond detectors

    International Nuclear Information System (INIS)

    Marczewska, B.; Bilski, P.; Olko, P.; Rebisz, M.; Nesladek, M.; Waligorski, M.P.R.

    2002-01-01

    A batch of 20 diamond detectors obtained by the chemical vapour deposition (CVD) method at the Institute for Materials Research at the Limburg University, Belgium, was investigated with respect to their thermoluminescent (TL) properties. The investigated detectors demonstrate TL sensitivity similar to that of the standard LiF:Mg, Ti (MTS) thermoluminescent detectors, lack of fading after two weeks from irradiation and apparent linearity of dose response. In spite of the persistent fluctuation of individual detector sensitivity observed in this batch, a new annealing procedure improved the stability of the TL signal. It has been concluded that 1 h annealing at 350 C assures the highest reproducibility for this set of detectors. A 30% discrepancy of the value of the TL signal between individual detectors from the batch may be caused by non-uniform distribution of dopants in the volume of the CVD diamond. A prototype of a planar TL reader equipped with a CCD camera was employed in this investigation. (Abstract Copyright [2002], Wiley Periodicals, Inc.)

  20. Pulse-shape discrimination between electron and nuclear recoils in a NaI(Tl) crystal

    Energy Technology Data Exchange (ETDEWEB)

    Lee, H.S. [Department of Physics, Ewha Womans University,Seoul 120-750 (Korea, Republic of); Adhikari, G.; Adhikari, P. [Department of Physics, Sejong University,Seoul 143-747 (Korea, Republic of); Choi, S. [Department of Physics and Astronomy, Seoul National University,Seoul 151-747 (Korea, Republic of); Hahn, I.S. [Department of Science Education, Ewha Womans University,Seoul 120-750 (Korea, Republic of)

    2015-08-18

    We report on the response of a high light-output NaI(Tl) crystal to nuclear recoils induced by neutrons from an Am-Be source and compare the results with the response to electron recoils produced by Compton-scattered 662 keV γ-rays from a {sup 137}Cs source. The measured pulse-shape discrimination (PSD) power of the NaI(Tl) crystal is found to be significantly improved because of the high light output of the NaI(Tl) detector. We quantify the PSD power with a quality factor and estimate the sensitivity to the interaction rate for weakly interacting massive particles (WIMPs) with nucleons, and the result is compared with the annual modulation amplitude observed by the DAMA/LIBRA experiment. The sensitivity to spin-independent WIMP-nucleon interactions based on 100 kg⋅year of data from NaI detectors is estimated with simulated experiments, using the standard halo model.

  1. Pulse-shape discrimination between electron and nuclear recoils in a NaI(Tl) crystal

    International Nuclear Information System (INIS)

    Lee, H.S.; Adhikari, G.; Adhikari, P.; Choi, S.; Hahn, I.S.

    2015-01-01

    We report on the response of a high light-output NaI(Tl) crystal to nuclear recoils induced by neutrons from an Am-Be source and compare the results with the response to electron recoils produced by Compton-scattered 662 keV γ-rays from a 137 Cs source. The measured pulse-shape discrimination (PSD) power of the NaI(Tl) crystal is found to be significantly improved because of the high light output of the NaI(Tl) detector. We quantify the PSD power with a quality factor and estimate the sensitivity to the interaction rate for weakly interacting massive particles (WIMPs) with nucleons, and the result is compared with the annual modulation amplitude observed by the DAMA/LIBRA experiment. The sensitivity to spin-independent WIMP-nucleon interactions based on 100 kg⋅year of data from NaI detectors is estimated with simulated experiments, using the standard halo model.

  2. Application of solid-phase micro extraction for the determination of pesticides in vegetable samples by gas chromatography with an electron capture detector

    International Nuclear Information System (INIS)

    Chai, Mee Kin; Tan, Guan Huat; Kumari, Asha

    2008-01-01

    A solid-phase micro extraction (SPME) method has been developed for the determination of 9 pesticides in 2 vegetables -cucumber and tomato - samples, based on direct immersion mode and subsequent desorption into the injection port of a gas chromatograph with an electron capture detector (GC-ECD). The main factors affecting the SPME process such as extraction time and temperature, desorption time and temperature, the effect of salt addition and fiber depth into the liner were studied and optimized. The analytical procedure proposed consisted of a 30 minute ultrasonic extraction of the target compounds from 1.0 g vegetable samples with 5 mL of distilled water. Then, the samples were filtered and topped up with distilled water to 10 mL. The analytes in this aqueous extract were extracted for 15 minutes with a 100 μm thickness polydimethylsiloxane SPME fiber. Relative standard deviations for triplicate analyses of samples were less than 10 %. The recoveries of the pesticides studied in cucumber and tomato ranged from 52 % to 82 % and the RSD were below 10 %. Therefore, the proposed method is applicable in the analysis of pesticides in vegetable matrices. SPME has been shown to be a simple extraction technique, which has a number of advantages such as solvent free extraction, simplicity and compatibility with the chromatographic analytical system. (author)

  3. Study of variations of radon emanations from soil in Morocco using solid state nuclear track detectors. Correlations with atmospheric parameters and seismic activities

    International Nuclear Information System (INIS)

    Boukhal, H.

    1993-01-01

    This study investigates the quantity variations of radon emanating from soil in accordance with time. It aims to verify the possibility of the radon sign use in earthquake prediction. Regular measures of radon concentration in soil have been carried out over the two years 1991 and 1992 in five towns of Morocco: Rabat, Tetouan, Ifrane and Khouribga, and in geophysic observatory of Ibn Rochd (Berchid region). The measuring method is based on the solid state nuclear track detectors technique. The obtained results have shown an influence of the atmospheric effects on the radon emanation. The experiment proved that, on one hand, the variations of the aforesaid influence are correlated to variations of the pluviometry and the atmospheric temperature and, on the other hand, there is no notable effect of atmospheric pressure or atmospheric humidity. The good correlations between the different seismic activities and the variations of radon emanation rate in the five measurement stations, have shown the interest of radon use in the earthquake prediction field. 81 refs., 100 figs., 17 tabs.(F. M.)

  4. Determination of acetanilide herbicides in cereal crops using accelerated solvent extraction, solid-phase extraction and gas chromatography-electron capture detector.

    Science.gov (United States)

    Zhang, Yaping; Yang, Jun; Shi, Ronghua; Su, Qingde; Yao, Li; Li, Panpan

    2011-07-01

    A method was developed to determine eight acetanilide herbicides from cereal crops based on accelerated solvent extraction (ASE) and solid-phase extraction (SPE) followed by gas chromatography-electron capture detector (GC-ECD) analysis. During the ASE process, the effect of four parameters (temperature, static time, static cycles and solvent) on the extraction efficiency was considered and compared with shake-flask extraction method. After extraction with ASE, four SPE tubes (graphitic carbon black/primary secondary amine (GCB/PSA), GCB, Florisil and alumina-N) were assayed for comparison to obtain the best clean-up efficiency. The results show that GCB/PSA cartridge gave the best recoveries and cleanest chromatograms. The analytical process was validated by the analysis of spiked blank samples. Performance characteristics such as linearity, limit of detection (LOD), limit of quantitation (LOQ), precision and recovery were studied. At 0.05 mg/kg spiked level, recoveries and precision values for rice, wheat and maize were 82.3-115.8 and 1.1-13.6%, respectively. For all the herbicides, LOD and LOQ ranged from 0.8 to 1.7 μg/kg and from 2.4 to 5.3 μg/kg, respectively. The proposed analytical methodology was applied for the analysis of the targets in samples; only three herbicides, propyzamid, metolachlor and diflufenican, were detected in two samples. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Vertex detectors

    International Nuclear Information System (INIS)

    Lueth, V.

    1992-07-01

    The purpose of a vertex detector is to measure position and angles of charged particle tracks to sufficient precision so as to be able to separate tracks originating from decay vertices from those produced at the interaction vertex. Such measurements are interesting because they permit the detection of weakly decaying particles with lifetimes down to 10 -13 s, among them the τ lepton and charm and beauty hadrons. These two lectures are intended to introduce the reader to the different techniques for the detection of secondary vertices that have been developed over the past decades. The first lecture includes a brief introduction to the methods used to detect secondary vertices and to estimate particle lifetimes. It describes the traditional technologies, based on photographic recording in emulsions and on film of bubble chambers, and introduces fast electronic registration of signals derived from scintillating fibers, drift chambers and gaseous micro-strip chambers. The second lecture is devoted to solid state detectors. It begins with a brief introduction into semiconductor devices, and then describes the application of large arrays of strip and pixel diodes for charged particle tracking. These lectures can only serve as an introduction the topic of vertex detectors. Time and space do not allow for an in-depth coverage of many of the interesting aspects of vertex detector design and operation

  6. Effect of cationic size in Hg (Tl/Bi) Ba2Ca2Cu3O8+δ on ...

    Indian Academy of Sciences (India)

    In this paper we have reported investigations on the effect of simultaneous substitution of Bi and Tl at the H site in the oxygen deficient HO layer of HBa2Ca2Cu3O8+ cuprate superconductor. Bulk polycrystalline samples have been prepared by the two-step solid state reaction process (precursor route). It has been ...

  7. Microcomputer control of automated TL reader

    International Nuclear Information System (INIS)

    Bjarland, B.

    1980-01-01

    An automatic TL reader has been developed for use within a TLD based personal monitoring service. A 6800 based microcomputer is used for system control, operator communication, calibration and checking of reader operation, and for output of data. The dosimeter identity code is printed in human readable characters on the dosimeter card, and is read by using an optical character recognition unit. The code may include individual sensitivity correction coefficients for the TL chips on the card. The chips are heated with hot nitrogen gas and the thermoluminescence is recorded by a photomultiplier tube circuit, the gain and offset of which are continuously monitored and, when necessary, adjusted, to maintain calibration. The reader may operate in any of seven modes, i.e. reading modes for three types of dosimeters, semiautomatic modes for production of the three types of dosimeters, and a monitor mode. (Auth.)

  8. Improving TL dosimetry for external radiotherapy

    International Nuclear Information System (INIS)

    Bustos, S.R.; Velez, G.; Rubio, M.

    1998-01-01

    Full text: In vivo thermoluminescence dosimetry (TLD) has always been one of the most accurate dosimetry method for external radiotherapy control, but the delay in the response is a well know drawback when it is applied. In this work we show some improvements and demonstrate that keeping the precision and accuracy of this technique, it is possible to obtain a response in few hours. Harshaw 4000 TL reader and LiF TLD-100 dosimeters, chips (3,1 x 3,1 x 0,9 mm 3 ) and rods (1 x 1 x 6 mm 3 ) have been used. The thermal treatment necessary to reuse the TLD is only 1h at 400 degree C, by using a glow curve analyser developed at the Ciemat (Spain), that allows a complete, prompt and precise identification of the individuals peaks. The dosimeters are periodically and individually calibrated. We also have study the factors contributing to the relation TL-dose like linearity, energy correction, directional response and fading. All those results are included into an Excel worksheet which automatically give us the dose resulting from the TL reading (peaks areas 4 and 5). The obtained uncertainty is better than 5%. The TLD already irradiated in radiotherapy institutions distant 30-40 Km from our centre can be read and analysed in about 3-4 hours. These facts render our methods rapid and allow a better control of radiotherapy treatment even if it is bi-fractionated. (author) [es

  9. Isotropic irradiation of detectors from point sources

    DEFF Research Database (Denmark)

    Aage, Helle Karina

    1997-01-01

    NaI(Tl) scintillator detectors have been exposed to gamma rays from 8 different point sources from different directions. Background and backscatter of gamma-rays from the surroundings have been subtracted in order to produce clean spectra. By adding spectra obtained from exposures from different ...

  10. Thallium (Tl) sorption onto illite and smectite: Implications for Tl mobility in the environment

    Science.gov (United States)

    Martin, Loïc A.; Wissocq, Aubéry; Benedetti, M. F.; Latrille, Christelle

    2018-06-01

    Clay minerals play a relevant role in the transport and fate of trace elements in the environment. Though illite has been referred as an important Thallium (Tl) bearing phase in soils, mechanisms and affinity of thallium for clay minerals remain poorly known. This study investigated the sorption behavior of thallium as Tl(I) onto illite and smectite, two clay minerals occurring mainly in soils and sediments. Different sorption experiments were carried out under various pH conditions and Tl concentrations, in competition with sodium and calcium at a constant ionic strength of 0.01 mol L-1. Our results showed that illite displayed more affinity than smectite for thallium. With illite, the distribution coefficients (Kd in L kg-1) varied between 102.75 ± 0.17 and 104.0 ± 0.17 in Na solutions versus between 102.25 ± 0.17 and 103.0 ± 0.17 in Ca solutions, depending on pH. With smectite, Kd (in L kg-1) ranged between 102.50 ± 0.16 and 103.20 ± 0.16 and between 101.25 ± 0.16 and 101.95 ± 0.16 in Na and Ca solutions, respectively. Sorption behavior was described with the Multi-Site Ion Exchanger model and selectivity coefficients with respect to protons were calculated for the first time. In all cases, independently of clay mineral and background electrolyte, low capacity but highly reactive sites were dominant in thallium uptake, highlighting Tl affinity for those sites. Moreover, the exchangeable and reversible interactions between Tl+ and clays reactive sites suggested that in changing conditions, thallium could be released in solution. The role of clay minerals in thallium environmental cycle is evident and confirmed illite to be a dominant Tl bearing phase, in some environment competing with manganese oxides. Compared to others Tl bearing mineral phases, clays are ranked as follows: MnO2 > illite > smectite ∼ ferrihydrite ≥ Al2O3 ∼ goethite > SiO2. Finally, over the three monovalent cations (Tl, Rb, Cs) Tl is the one less sorbed on illite independently of

  11. Nuclearites search with the TLS detector

    International Nuclear Information System (INIS)

    Liang, S.; Wada, T.; Nakatsuka, T.; Okei, K.; Saavedra, O.; Takahashi, N.; Tsuji, S.; Yamamoto, I.; Yamashita, Y.; Lan, S.; Okita, M.; Takahashi, N.; Morita, T.; Ishii, R.; Goto, Y.; Iyono, A.; Matsumoto, H.; Nakagawa, M.; Noda, C.; Masuda, M.

    2008-01-01

    It is shown that a thermoluminescent sheet stack (TLS) detector, consisting of TL sheets and medical x-ray films, is an effective nuclearite detector. The TLS can be used for searching lighter nuclearites at sea level owing to the fact that the usual relativistic particles cannot make their tracks in the TLS unless they have a charge of larger than 50. We will report recent results of searching for lighter nuclearites at sea level

  12. Study of the influence of the soil and plant natures and pollution on the radon and thoron alpha activities inside various herbal infusions by using solid state nuclear track detectors

    International Nuclear Information System (INIS)

    Misdaq, M.A.; Ait nouh, F.; Bourzik, W.; Lamine, J.

    2000-01-01

    Different medicinal plant, spinach and cereal samples have been analysed by using neutron activation analysis and radiochemical separation. The solid state nuclear track detectors technique was utilized for uranium and thorium contents determination as well as for alpha, beta, and gamma dose rates evaluation in various geological and ceramic samples. In this study, uranium and thorium contents have been determined in different plant samples, soils in which they have been grown and in herbal infusions made by boiling the studied plants in potable water by using CR-39 and LR-115 solid state nuclear track detectors. Radon and thoron alpha activities per unit volume inside the plants, soils and herbal infusions studied have been evaluated. The radon transfers between soils and plants as well as between plants and herbal infusions have been investigated. The influence of pollution due to different material dusts on radon and thoron alpha activities inside the plants and their corresponding infusions has been studied. (author)

  13. Calculation of the Intensity of electrical field at the end of the loaded path in the solid-state nuclear track detectors by using the numerical calculation of Laplace equations

    International Nuclear Information System (INIS)

    Kolahdooz, M.; Abotalebi, A.; Sheikh Aleslam, F.

    2011-01-01

    The goal of this article is calculation of the electric field at the end of loaded path in solid-state track detectors. For the calculation, Laplace-Equation has been solved numerically. By solving the equation, upon considering a specific potential at the boundary of the region, in addition to calculating the electric field at the end of path, the parameters which are affecting the electric field have also been investigated.

  14. Radiation detectors

    International Nuclear Information System (INIS)

    2013-01-01

    This sixth chapter presents the operational principles of the radiation detectors; detection using photographic emulsions; thermoluminescent detectors; gas detectors; scintillation detectors; liquid scintillation detectors; detectors using semiconductor materials; calibration of detectors; Bragg-Gray theory; measurement chain and uncertainties associated to measurements

  15. Detector for atomic particles and ionizing radiations

    International Nuclear Information System (INIS)

    Mallet, Georges; Ythier, Christian.

    1976-01-01

    The aim of this invention is to provide improved detectors of atomic particles and of ionising radiations, having maximum sensitivity, by virtually suppressing all absorption of the radiation scattered by the main detector, so that these detectors are particularly suitable for fitting to anti-Compton spectrometers. Reference is particularly made to detectors of the Ge(Li) type, lithium compensated germanium, which are the most used. It is however made clear that this choice is not restrictive and that this invention not only applies to all known types of detectors and particularly to scintillator detectors, for instance to detectors such as NaI (Tl), composed of a monocrystal of a thallium activated alkaline halogenide, but also to gas, ionisation chamber and luminescent chamber type detectors and in general to all the known devices that convert the energy of particles into electric signals. Owing to the fact that the walls of the enclosure containing the main detector are composed, in the part around this detector, of an auxiliary detector, the latter detects virtually all the radiations scattered by the main detector. It does so without any loss due to the absorption of these radiations (a) by the metal walls of the enclosure usually containing the main detector and (b) by the walls of the auxiliary detector casing. It results from this that the detectors of the invention enable coincidence or anti-coincidence spectrometers with a very high performance to be made [fr

  16. NaI Detector Network at Aragats

    International Nuclear Information System (INIS)

    Avakyan, Karen; Arakelyan, Karen; Chilingarian, Ashot; Daryan, Ara; Kozliner, Lev; Mailyan, Bagrat; Hovsepyan, Gagik; Pokhsraryan, David; Sargsyan, David

    2013-01-01

    The Aragats Space Environmental Center (ASEC) provides monitoring of different species of secondary cosmic rays and consists of two high altitude research stations on Mt. Aragats in Armenia. Along with solar modulation effects, ASEC detectors register several coherent enhancements associated with thunderstorm activity. The experimental techniques used allowed for the first time to simultaneously measure fluxes of the electrons, muons, gamma rays, and neutrons correlated with thunderstorm activity. Ground-based observations by a complex of surface particle detectors, measuring in systematically and repeatable fashion, gamma quanta, electrons, muons and neutrons from atmospheric sources are necessary for proving the theory of particle acceleration and multiplication during thunderstorms. Energy spectra and correlations between fluxes of different particles, measured on Earth's surface address the important issues of research of the solar modulation effects and the atmospheric high-energy phenomena. In May 26 2011, launched 5 NaI(Tl) (thallium-doped sodium iodide) scintillation detectors and 1 plastic one in the new ASEC laboratory on Aragats to detect low energy gamma rays from the thunderclouds and short particle bursts. Including NaI(Tl) detectors in ASEC detectors system is of great importance for investigation thunderstorm phenomena because NaI(Tl) detectors have high efficiency of gamma ray detecting in comparison with plastic ones.

  17. New colour centres in KCl:(Tl+ + Ca2+) and KCl:(Tl+ + Sr2+) crystals

    International Nuclear Information System (INIS)

    Ioan, A.; Topa, V.; Giurgea, M.

    1978-01-01

    Electrolytic colouring under unusual conditions (low temperature and high voltage) gives rise to the appearance of three new absorption bands peaking at 3.2, 2.5, and 1.7 eV and at 2.8, 2.1, and 1.5 eV in KCl:(Tl + + Ca 2+ ) and in KCl:(Tl + + Sr 2+ ) single crystals, respectively. The modifications of the absorption spectra of the coloured crystals induced by the application of a reversed electric field at the colouring temperature or by heat treatment are investigated. It is likely that the colour centre responsible for the new absorption bands is an aggregate centre which, besides an Tl - -complex, contains also at least an Ca(Sr) ion, a trapped electron, and an anionic vacancy. (author)

  18. Copper interactions in TlCu7S4 and TlCu7Se4

    International Nuclear Information System (INIS)

    Noren, L.; Delaplane, R.G.; Berger, R.

    1999-01-01

    Complete text of publication follows. The copper chalcogenides ACu 7 S 4 (A=NH 4 + , Tl + , Rb + ) are quasi-one-dimensional metals at ambient and higher temperatures which is due to the high mobility of copper in these structures. TlCu 7 S 4 and TlCu 7 Se 4 are isostructural compounds, space group I4/m, which can be described on the basis of a TlX 8 cube with two different Cu sites, Cu(1) and Cu(2). Cu(2)-Cu(2) zigzag chains run along the c axis with only 3/4 occupation of the Cu(2) sites. However, these two compounds differ in behaviour on cooling. The sulphide shows a polymorphic first-order transition to the CsAg 7 S 4 type (P4/n) owing to ordering of the vacancies in the Cu(2)-Cu(2) chains. In order to study the nature of the Cu(2) order/disorder in the two title compounds, a series of neutron diffraction measurements (both Bragg and diffuse scattering) were made at several temperatures from 40 to 713 K on the instrument SLAD at Studsvik. The structure at each temperature was modelled using RMC techniques. The resulting configuration show that as the temperature increases, there is a marked increase in the mobility of the Cu atoms in the Cu(2)-Cu(2) chains for TlCu 7 S 4 but not for TlCu 7 Se 4 . This is due to the initial difference in the Cu(2)-Cu(2) distances, only 2.2A for the thiocuprate, but 2.7A in the selenocuprate which explains the relative ease for Cu(2) ordering in the latter case. (author)

  19. Insight on a novel layered semiconductors: CuTlS and CuTlSe

    Energy Technology Data Exchange (ETDEWEB)

    Aliev, Ziya S., E-mail: ziyasaliev@gmail.com [Institute of Catalysis and Inorganic Chemistry, ANAS, H.Javid ave. 113, AZ1143 Baku (Azerbaijan); Institute of Physics, ANAS, H.Javid ave. 131, AZ1143 Baku (Azerbaijan); Donostia International Physics Center (DIPC), 20080 San Sebastian (Spain); Zúñiga, Fco. Javier [Departamento de Física de la Materia Condensada, Facultad de Ciencia y Tecnología, Universidad del País Vasco, Apdo. 644, 48080 Bilbao (Spain); Koroteev, Yury M. [Institute of Strength Physics and Materials Science, Russian Academy of Sciences, Siberian Branch, 634055 Tomsk (Russian Federation); Tomsk State University, Tomsk, 634050 (Russian Federation); Breczewski, Tomasz [Departamento de Física de la Materia Condensada, Facultad de Ciencia y Tecnología, Universidad del País Vasco, Apdo. 644, 48080 Bilbao (Spain); Babanly, Nizamaddin B. [Institute of Catalysis and Inorganic Chemistry, ANAS, H.Javid ave. 113, AZ1143 Baku (Azerbaijan); Amiraslanov, Imamaddin R. [Institute of Physics, ANAS, H.Javid ave. 131, AZ1143 Baku (Azerbaijan); Politano, Antonio [Department of Physics, University of Calabria, 87036 Rende (CS) (Italy); Madariaga, Gotzon [Departamento de Física de la Materia Condensada, Facultad de Ciencia y Tecnología, Universidad del País Vasco, Apdo. 644, 48080 Bilbao (Spain); Babanly, Mahammad B. [Institute of Catalysis and Inorganic Chemistry, ANAS, H.Javid ave. 113, AZ1143 Baku (Azerbaijan); and others

    2016-10-15

    Single crystals of the ternary copper compounds CuTlS and CuTlSe have been successfully grown from stoichiometric melt by using vertical Bridgman-Stockbarger method. The crystal structure of the both compounds has been determined by powder and single crystal X-Ray diffraction. They crystallize in the PbFCl structure type with two formula units in the tetragonal system, space group P4/nmm, a=3.922(2); c=8.123(6); Z=2 and a=4.087(6); c=8.195(19) Å; Z=2, respectively. The band structure of the reported compounds has been analyzed by means of full-potential linearized augmented plane-wave (FLAPW) method based on the density functional theory (DFT). Both compounds have similar band structures and are narrow-gap semiconductors with indirect band gap. The resistivity measurements agree with a semiconductor behavior although anomalies are observed at low temperature. - Graphical abstract: The crystal structures of CuTl and CuTlSe are isostructural with the PbFCl-type and the superconductor LiFeAs-type tetragonal structure. The band structure calculations confirmed that they are narrow-gap semiconductors with indirect band gaps of 0.326 and 0.083 eV. The resistivity measurements, although confirming the semiconducting behavior of both compounds exhibit unusual anomalies at low temperatures. - Highlights: • Single crystals of CuTlS and CuTlSe have been successfully grown by Bridgman-Stockbarger method. • The crystal structure of the both compounds has been determined by single crystal XRD. • The band structure of the both compounds has been analyzed based on the density functional theory (DFT). • The resistivity measurements have been carried out from room temperature down to 10 K.

  20. Scintillation response of CsI: Tl crystal under neutron, gamma, alpha particles and beta excitations

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Maria da Conceicao Costa; Madi Filho, Tufic; Lopes, Valdir Maciel; Berretta, Jose Roberto; Cardenas, Jose Patricio Nahuel, E-mail: macoper@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    Among the converters of X and gamma radiation in light photons, known as scintillators, the one which is the most efficient emits photons with a wavelength near 400 nm. Particularly, among them, the cesium iodine doped with thallium (CsI:Tl) crystal is that which matches better between the light emission spectrum (peak at 540 nm) and the quantum sensitivity curve of the photodiodes and CCD (Charge Coupled Device). This explains the renewed interest in using this crystal as scintillator. Although the CsI:Tl crystal is commercially available, its local development would give the possibility to obtain it in different geometric configurations and coupling. Moreover, there is a special interest in studying new conditions that will alter the properties of this crystal in order to achieve a optimal level of its functional characteristics. Having an efficient national scintillator with low cost is a strategic opportunity to study the response of a detector applied to different types of radiation. The crystal of cesium iodide activated with thallium (CsI:Tl) has a high gamma detection efficiency per unit volume. In this paper, the CsI:Tl crystal, grown by the vertical Bridgman technique in evacuated silica ampoules and with the purpose of use as radiation detectors, is described. To evaluate the scintillator, measures of the thallium distribution in the crystal volume were taken, with overall efficiency score. The scintillator response was studied through gamma radiation from sources of {sup 137}Cs, {sup 60}Co, {sup 22}Na, {sup 54}Mn, {sup 131}I and {sup 99m}Tc; the beta radiation from source of {sup 90}Sr/{sup 90}Y, alpha particles from {sup 241}Am source and the scintillator response to neutrons from Am/Be source. The energetic resolution for {sup 137}Cs gamma rays (662 keV) was 10%. The results showed the validity of using the CsI:Tl crystal developed in our laboratory, in many applications in the area of radiation detectors. (author)

  1. Tl-201 per rectum scintigraphy in chronic liver disease: assessment of Tl-201 uptake indices

    International Nuclear Information System (INIS)

    Moon, Won Jin; Choi, Yun Young; Cho, Suk Shin; Lee, Min Ho

    1999-01-01

    Heart to liver ratio on Tl-201 per rectal scintigraphy (shunt index) is known to be useful in the assessment of portal systemic shunt. We assessed Tl-201 uptake pattern and early liver/heart uptake rate of Tl-201 and correlated with shunt index in patients with chronic active hepatitis (CAH) and liver cirrhosis (LC). Fifty eight patients with biopsy-proven chronic liver disease (35 with CAH, 23 with LC) underwent Tl-201 per rectum scintigraphy after instillation of 18.5 MBq of Tl-201 into the upper rectum. We evaluated hepatic uptake (type 1: homogeneous, 2: inhomogeneous segmental, 3: inhomogeneous nonsegmental) and extrahepatic uptake of spleen, heart and kidney (grade 0: no uptake, 1: less than liver, 2: equal to liver, 3: greater than liver). We measured the early liver/heart uptake rate (the slope of the liver to heart uptake ratio for 10 mim) and shunt index (heart to liver uptake ratio). Tl-201 uptake pattern and early liver/heart uptake rate of Tl-201 was correlated with the pathologic diagnosis and shunt index. Hepatic uptake patterns of type 1 and 2 were dominant in CAH (CAH: 27/35, LC: 8/23), and type 3 in LC (CAH: 8/35, LC: 15/23)(p<0.005). The grades of extrahepatic uptake were higher in LC than in CAH (spleen: p<0.001, other soft tissue: p<0.005). The early liver/heart uptake rate of CAH (0.110±0.111) was significantly higher than that of LC (0.014±0.090)(p<0.001). The sensitivity and specificity of the early liver/heart uptake rate were 77.7% and 67.7% in differentiating LC from CAH. There was negative correlation between early liver/heart uptake rate and shunt index (r=-0.3347, p<0.01). Hepatic and extrahepatic uptake pattern and early liver/heart uptake rate on Tl-201 per rectum scintigraphy are useful in the assessment of portal systemic shunt in patients with chronic liver disease

  2. Simultaneous quantification of six alkaloid components from commercial stemonae radix by solid phase extraction-high-performance liquid chromatography coupled with evaporative light scattering detector

    Science.gov (United States)

    Zhang, Rong-Rong; Lu, Dan-Yi; Yang, Zhen-Ya; Zhao, Wen; But, Paul Pui-Hay; Shaw, Pang-Chui; Jiang, Ren-Wang; Ma, Zhi-Guo

    2015-01-01

    Background: Stemonae radix has been applied in traditional Chinese medicine for centuries. Alkaloids are the main active ingredient in stemonae radix, so their composition and concentration levels are directly linked to clinic effects. Objective: The objective was to develop an analytical method with multiple markers for quality survey of commercial stemonae radix. Materials and Methods: A method for simultaneous determination of six compounds in commercial stemonae radix was performed using solid-phase extraction and high-performance liquid chromatography coupled with evaporative light scattering detector. The separation was carried out on an Agilent TC-C18 column with 0.1% acetonitrile solution of triethylamine aqueous solution and acetonitrile as the mobile phase under gradient elution within 70 min. The hierarchical clustering analysis (HCA) was successfully used to classify the samples in accordance with their chemical constituents. Results: Linearity (R2 > 0.9990), intra- and inter-day precision (relative standard deviations <4%), limit of detection (0.011–0.086 μg/mL), limit of quantification (0.033–0.259 μg/mL) of the six alkaloids were determined, and the recoveries were between 96.6% and 103.7%. The method was successfully applied to analysis 36 batches of commercial stemonae radix. All the samples could be classified into five clusters by HCA. Conclusion: This article provides an accurate and simple analytical method for quality survey of commercial stemonae radix. Because of the significant chemical variations, careful selection of Stemona sources with obvious antitussive value but devoid of croomine followed by good agricultural practice and good manufacturing practice process is suggested. PMID:25829776

  3. Determination of organophosphorus flame retardants in fish by pressurized liquid extraction using aqueous solutions and solid-phase microextraction coupled with gas chromatography-flame photometric detector.

    Science.gov (United States)

    Gao, Zhanqi; Deng, Yuehua; Yuan, Wenting; He, Huan; Yang, Shaogui; Sun, Cheng

    2014-10-31

    A novel method was developed for the determination of organophosphorus flame retardants (PFRs) in fish. The method consists of a combination of pressurized liquid extraction (PLE) using aqueous solutions and solid-phase microextraction (SPME), followed by gas chromatography-flame photometric detector (GC-FPD). The experimental parameters that influenced extraction efficiency were systematically evaluated. The optimal responses were observed by extracting 1g of fish meat with the solution of water:acetonitrile (90:10, v/v) at 150°C for 5min and acid-washed silica gel used as lipid sorbent. The obtained extract was then analyzed by SPME coupled with GC-FPD without any additional clean-up steps. Under the optimal conditions, the proposed procedure showed a wide linear range (0.90-5000ngg(-1)) obtained by analyzing the spiked fish samples with increasing concentrations of PFRs and correlation coefficient (R) ranged from 0.9900 to 0.9992. The detection limits (S/N=3) were in the range of 0.010-0.208ngg(-1) with standard deviations (RSDs) ranging from 2.0% to 9.0%. The intra-day and inter-day variations were less than 9.0% and 7.8%, respectively. The proposed method was successfully applied to the determination of PFRs in real fish samples with recoveries varying from 79.8% to 107.3%. The results demonstrate that the proposed method is highly effective for analyzing PFRs in fish samples. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Applicability of a portable CdTe and NaI (Tl) spectrometer for activity measure

    International Nuclear Information System (INIS)

    Fernandes, Jaquiel Salvi

    2005-02-01

    In this work it was studied the application of an in situ gamma spectrometer (ROVER) of Amptek Inc., composed by a Cadmium Telluride detector (CdTe) of 3 mm x 3 mm x 1 mm and a 30 mm x 30 mm Sodium Iodide detector doped with Thallium [NaI (Tl)). The radioactive sources used were type pastille, sealed in aluminum and polyethylene, of 241 Am, 133 Ba, 152 Eu, 3 sources of 137 Cs and soil samples contaminated with 137 Cs. It was performed a factorial planning 2 3 to optimize the in situ spectrometry system. This way it was determined that the best temperature for CdTe crystal operation is -22, deg C, with Shaping Time of 3 μS and Rise Time Discrimination (RTD) with value 3. With the help of the certified radioactive sources, we determined the efficiency curve of the two detectors. The CdTe detector was positioned at the standard distance of 1 meter of the sources and also at 4.15 cm. The NaI (Tl) detector was also positioned at the standard distance of 1 meter of the sources and at 2.8 cm. Measures were performed to determine the Minimum Detectable Activity (MDA) for both detectors. For the pastille type sources, the 137 Cs MDA for the CdTe detector at 4.15 cm, analyzing the energy line of 32 keV, was 6 kBq and at 1 meter of the 137 Cs source, analyzing the line of 661.65 keV, the MDA was 67 kBq. For soil samples, CdTe detector at 4.15 cm presented a MDA of 693 kBq.kg-l for the line of 32 keV, and for the soil sample 7 Be content the MDA found was 2867 Bq.kg -1 at 4.15 cm. For the NaI (Tl) detector, analyzing the line of 661.65 keV, the 137 Cs MDA for pastille type source at 1 meter of distance was 7 kBq, and for soil sample at 2.8 cm the measured 137 Cs MDA was 71 Bq.kg -1 . For the soil sample 7 Be content, at 2.8 cm of the Nal (Tl) detector, the obtained MDA was 91 Bq.kg -1 . Due to the minimum detectable activities found for the two detectors, we concluded that the employed in situ gamma ray spectrometer system allows the quantification of 137 Cs and 7 Be

  5. Computerized study with /sup 201/Tl of the cold thyroid node

    Energy Technology Data Exchange (ETDEWEB)

    Palermo, F.; Saitta, B.; Coghetto, F.; Tiberio, M.; Caldato, L.

    1982-02-01

    Because of its physical and potassium-metabolic characteristics /sup 201/Tl is more suitable than /sup 131/Cs for radioisotopic studies of the cold thyroid nodule, with the further diagnostic possibility of quantitatively assessing intranodular behaviour for a specific differentiation among different kinds of neoformations. Using a gamma-camera on line with a computer data processing device, sequential scintiscans were recorded for the first 20-30 min after i.v. administration of 15-20 ..mu..Ci/kg of radiothallium; delayed sequences were taken at 40-60 min if intranodular uptake appeared. A quantitative appraisal was made of the differential /sup 201/Tl uptake-ratio between nodule and healthy thyroid tissue (density-index) and the multiparameter analysis of thyroid time/activity curves generated on the relative regions of interest (ROIs). This computerized study, in 120 out of 293 patients submitted to this radiothallium test, has shown a) diagnostic agreement between clinical-histological and radioisotopic findings in 76 out of 79 colloid-cystic or degenerative neoformations, in all 16 malignant and in 23 out of 25 hyperplastic benign nodules; b) significant statistical difference of the density-index in solid versus cystic but not between benign and malignant nodules; c) different /sup 201/Tl kinetics behaviour in different kinds of solid thyroid lesions with a satisfactory statistical difference of the radiothallium nodular dissappearance-index.

  6. 207Pb and 205Tl NMR on Perovskite Type Crystals APbX3 (A = Cs, Tl, X = Br, I)

    Science.gov (United States)

    Sharma, Surendra; Weiden, Norbert; Weiss, Alarich

    1987-11-01

    By 205Tl and 207Pb NM R the chemical shift in polycrystalline samples of binary halides AX, BX2 and ternary halides ABX3 (A = Cs, Tl; B = Pb; X = Br, I) was studied at room temperature. The chemical shift tensors δ ( 205Tl) and δ (207Pb) were determined in magnitude and orientation on single crystals of the orthorhombic TlPbI3. The components of the δ(205Tl) tensor are δx (205Tl) || a = 611ppm; δy (205Tl) || b = 680 ppm; δZ(205Tl) || c = 1329 ppm; δiso(205Tl) = 873.3 ppm (with respect to 3.4 molar aqueous solution of TlOOCCH3). The chemical shift tensor of 207Pb in TlPbI3 shows two orientations. One of them is: δx (207Pb) = 3760 ppm, inclined 30° from b towards c, δy(207Pb) || a = 3485 ppm, δz(207Pb) = 2639 ppm inclined 120° from b towards c. δiso(207Pb) = 3295 ppm (with respect to saturated aqueous solution of Pb(NO3)2). The results are discussed with respect to the crystal structure and a model to explain orientation and anisotropy of the tensors δ(205Tl) and δ(207Pb) in TlPbI3 is proposed. In the system CsPbBr3-x Ix δ(207Pb) was studied on polycrystalline samples. The chemical shift increases with increasing x and negative excess shift is observed.

  7. Pixellated thallium bromide detectors for gamma-ray spectroscopy and imaging

    Energy Technology Data Exchange (ETDEWEB)

    Onodera, T. E-mail: tosiyuki@smail.tohtech.ac.jp; Hitomi, K.; Shoji, T.; Hiratate, Y

    2004-06-01

    Recently, pixellated semiconductor detectors exhibit high-energy resolution, which have been studied actively and fabricated from CdTe, CZT and HgI{sub 2}. Thallium bromide (TlBr) is a compound semiconductor characterized with its high atomic numbers (Tl=81, Br=35) and high density (7.56 g/cm{sup 3}). Thus, TlBr exhibits higher photon stopping power than other semiconductor materials used for radiation detector fabrication such as CdTe, CZT and HgI{sub 2}. The wide band gap of TlBr (2.68 eV) permits the detectors low-noise operation at around room temperature. Our studies made an effort to fabricate pixellated TlBr detectors had sufficient detection efficiency and good charge collection efficiency. In this study, pixellated TlBr detectors were fabricated from the crystals purified by the multipass zone-refining method and grown by the horizontal traveling molten zone (TMZ) method. The TlBr detector has a continuous cathode over one crystal surface and 3x3 pixellated anodes (0.57x0.57 mm{sup 2} each) surrounded by a guard ring on the opposite surface. The electrodes were realized by vacuum evaporation of palladium through a shadow mask. Typical thickness of the detector was 2 mm. Spectrometric performance of the TlBr detectors was tested by irradiating them with {sup 241}Am (59.5 keV), {sup 57}Co (122 keV) and {sup 137}Cs (662 keV) gamma-ray sources at temperature of -20 deg. C. Energy resolutions (FWHM) were measured to be 4.0, 6.0 and 9.7 keV for 59.5, 122 and 662 keV gamma-rays, respectively.

  8. TL Dosimetry on the Tandetron Ion Accelerator area of the ININ; Dosimetria TL en el area del Acelerador de iones Tandetron del ININ

    Energy Technology Data Exchange (ETDEWEB)

    Valdovinos A, M.A.; Gonzalez M, P.R. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    2000-07-01

    For the fulfilment of the operation tests of the Positive Ions type Tandetron 4120 MC, 2 MV, it was obtained the permission consented by the National Commission of Nuclear safety and safeguards (CNSNS). During the stage of tests were arranged Tl dosemeters in the Tandetron Accelerator area, as well as toward to the beam exit. In this work, it was presented the results obtained of the measurement of radiation levels, as much in the area as in the beam exit. This Accelerator is useful in different fields of science such as: biology, radiochemistry, materials, solid state physics, archaeology and environmental sciences between others. (Author)

  9. Improvements in the Tl dosimetry for Radiotherapy

    International Nuclear Information System (INIS)

    Bustos, S.; Velez, G.; Rubio, M.

    1998-01-01

    The thermoluminescent dosimetry (TLD) in vivo has been demonstrated to be one of the most reliable for the control of radiotherapeutic treatments, but the delay in the response is the main disadvantage in its applicability. In this work are presented important improvements and it is demonstrated that maintaining the accuracy and reliability of the technique, it is possible to accelerate the response times at a few hours. To realize this work is utilized a lecturer Harshaw 4000, dosemeters LiF-TLD-100 chips (3.1 x 3.1 x 0.89 mm 3 ) and rods (1 x 1 x 6 mm 3 ). With the implementation of a glow curve analysis program developed in CIEMAT, its obtained a Tl peaks separation in such manner rapid and accurate, by that the thermal treatment of dosemeters may be reduced at one unique annealing pre-irradiation for 1 hr at 400 Centigrade. It is realized a periodical and individual calibration of the TLD and a study of the factors which influencing the ratio Tl signal-dose as linearity, correction by energy, directional response and pride of Tl signal. the results of this study are introducing in a calculation list specially designed and which allows to obtain absorbed dose by TLD starting of the dates (dosimetric peaks area) which appear of the glow curves analysis. The dose is obtained with an accuracy less than 5 %. The dosemeters already irradiated (in vivo) are analysed and informed in only four hours, allowing a greater control of the treatment and a correction of the possible errors for the next session, still in bi fractional treatments. The method implemented results thus accurate, rapid and reliable. (Author)

  10. Compact Solid State Terahertz Detectors

    Science.gov (United States)

    2007-07-09

    by the optical features mnH (L) that could be associated with excitonic transitions in the MQW region of the samples. The notation mnH (L) signifies...originating due to internal electric fields in the samples [1, 2]. In addition to the FKOs, at higher energies, a number of mnH (L) features...associated with the excitonic transitions in the MQW region of the samples are observed. The notation mnH (L) signifies here the transitions between the m

  11. The TL dating of ancient porcelain

    International Nuclear Information System (INIS)

    Leung, P.L.; Stokes, M.J.; Wang Weida; Xia Junding; Zhou Zhixin

    1997-01-01

    The age determination of ancient porcelain using the pre-dose technique in TL dating was reported. The variation of beta dose with depth below the surface of the porcelain slice, the thermal activation characteristic (TAC) for 110 degree C peak, the measurement of paleodose and the estimation of annual dose were studied. The results show that this technique is suitable for authenticity testing of ancient porcelain, but both accuracy and precision for porcelain dating are worse than those for pottery, because porcelain differs from pottery on composition, structure and firing temperature. Besides, some complicated factors in the pre-dose technique would be the possible cause of the greater errors

  12. High-pressure single-crystal X-ray diffraction of Tl2SeO4

    International Nuclear Information System (INIS)

    Grzechnik, Andrzej; Breczewski, Tomasz; Friese, Karen

    2008-01-01

    The effect of pressure on the crystal structure of thallium selenate (Tl 2 SeO 4 ) (Pmcn, Z=4), containing the Tl + cations with electron lone pairs, has been studied with single-crystal X-ray diffraction in a diamond anvil cell up to 3.64 GPa at room temperature. No phase transition has been observed. The compressibility data are fitted by a Murnaghan equation of state with the zero-pressure bulk modulus B 0 =29(1) GPa and the unit-cell volume at ambient pressure V 0 =529.6(8) A 3 (B'=4.00). Tl 2 SeO 4 is the least compressible in the c direction, while the pressure-induced changes of the a and b lattice parameters are quite similar. These observations can be explained by different pressure effects on the nine- and 11-fold coordination polyhedra around the two non-equivalent Tl atoms. The SeO 4 2- tetrahedra are not rigid units and become more distorted. Their contribution to the compressibility is small. The effect of pressure on the isotypical oxide materials A 2 TO 4 with the β-K 2 SO 4 structure is discussed. It appears that the presence of electron lone pairs on the Tl + cation does not seem to influence the compressibility of Tl 2 SeO 4 . - Graphical abstract: Pressure dependence of normalized lattice parameters and unit-cell volumes in Tl 2 SeO 4 (Pmcn, Z=4). The solid line is the Murnaghan equation of state

  13. Substitution of indium for chromium in TlIn5−xCrxSe8: crystal structure of TlIn4.811(5Cr0.189(5Se8

    Directory of Open Access Journals (Sweden)

    Robin Lefèvre

    2017-04-01

    Full Text Available The new thallium penta(indium/chromium octaselenide, TlIn4.811(5Cr0.189(5Se8, has been synthesized by solid-state reaction. It crystallizes isotypically with TlIn5Se8 in the space group C2/m. Although the two Tl positions are disordered and only partially occupied, no Tl deficiency was observed. The insertion of chromium in the structure has been confirmed by EDS analysis. Chromium substitutes indium exclusively at one of three In sites, viz. at one of the positions with site symmetry 2/m (Wyckoff position 2a. In the crystal structure, edge-sharing InSe6 octahedra, and (In,CrSe6 octahedra and InSe4 tetrahedra make up two types of columns that are linked into a framework in which two different types of channels parallel to [010] are present. The Tl atoms are located in the larger of the channels, whereas the other, smaller channel remains unoccupied.

  14. Prediction of Phase Separation of Immiscible Ga-Tl Alloys

    Science.gov (United States)

    Kim, Yunkyum; Kim, Han Gyeol; Kang, Youn-Bae; Kaptay, George; Lee, Joonho

    2017-06-01

    Phase separation temperature of Ga-Tl liquid alloys was investigated using the constrained drop method. With this method, density and surface tension were investigated together. Despite strong repulsive interactions, molar volume showed ideal mixing behavior, whereas surface tension of the alloy was close to that of pure Tl due to preferential adsorption of Tl. Phase separation temperatures and surface tension values obtained with this method were close to the theoretically calculated values using three different thermodynamic models.

  15. Advanced Space Radiation Detector Technology Development

    Science.gov (United States)

    Wrbanek, John D.; Wrbanek, Susan Y.; Fralick, Gustave C.

    2013-01-01

    The advanced space radiation detector development team at the NASA Glenn Research Center (GRC) has the goal of developing unique, more compact radiation detectors that provide improved real-time data on space radiation. The team has performed studies of different detector designs using a variety of combinations of solid-state detectors, which allow higher sensitivity to radiation in a smaller package and operate at lower voltage than traditional detectors. Integration of multiple solid-state detectors will result in an improved detector system in comparison to existing state-of-the-art instruments for the detection and monitoring of the space radiation field for deep space and aerospace applications.

  16. Time of gamma radiation transport in NaI(Tl) scintillators

    International Nuclear Information System (INIS)

    Matarrita, A.S.

    1976-01-01

    The distribution of time intervals in function of the energy, ocurred between the incidence of a gamma radiation in the face of a scintillation crystal and the arrival of the correspondent scintillation at photocathode, is calculated. The mean square fluctuation these time interval, relating to resolution of the detector system is determined. The calculations are done for NaI (Tl) cylindrical crystals with the radiation source placed in the symmetry axis, in two situations: para axial incidence and oblique incidence, indicating a good agreement with experimental data. (M.C.K.) [pt

  17. Characterization of cartilaginous tumors with 201Tl scintigraphy

    International Nuclear Information System (INIS)

    Higuchi, Takahiro; Taki, Junichi; Sumiya, Hisashi; Kinuya, Seigo; Nakajima, Kenichi; Tonami, Norihisa

    2005-01-01

    Histological diagnosis and grading of cartilaginous tumors are closely correlated with patient prognosis; consequently, they are essential elements. We attempted to clarify the characteristics of 201 Tl uptake in various histological types of cartilaginous tumors and to assess its clinical value. Twenty-two cases with histologically proven cartilaginous tumors (3 enchondromas, 15 conventional chondrosarcomas (grade I=9, II=5, III=1), 3 mesenchymal chondrosarcomas, and 1 de-differentiated chondrosarcoma) were examined retrospectively. Planar 201 Tl images were recorded 15 mm following intravenous injection of 201 Tl (111 MBq). 201 Tl uptake in the tumor was evaluated visually employing a five-grade scoring system: 0=no appreciable uptake, 1=faint uptake above the background level, 2=moderate uptake, 3=intense uptake but lower than heart uptake and 4=uptake higher than heart uptake. 201 Tl uptake scores were 0 in 3 of 3 enchondromas, 9 of 9 grade I, and 4 of 5 grade II conventional chondrosarcomas. 201 Tl uptake scores were 1 among 1 of 5 grades II and a grade III conventional chondrosarcoma. Mesenchymal chondrosarcoma and de-differentiated chondrosarcoma displayed 201 Tl uptake scores of 2 or 3. Absence of elevated 201 Tl uptake in cartilaginous tumors was indicative of enchondroma or low-grade conventional chondrosarcoma. However, in instances in which 201 Tl uptake is obvious, high-grade chondrosarcoma or variant types should be considered. (author)

  18. Methods, qualitative and quantitative evaluations of 201Tl myocardial scintiscans

    International Nuclear Information System (INIS)

    Buell, U.; Kleinhans, E.; Klepzig, M.; Seiderer, M.; Strauer, B.E.

    1981-01-01

    Exercise 201 Tl myocardial scintiscanning is a technique used to supplement exercise electrocardiography. The procedure employed should be identical to the standard procedure of electrocardiography. If the coronary disease has already been established by coronary angiography and kineventriculography, 201 Tl examinations should be carried out before surgery in order to determine the ''regional functional reserve''. Visual evaluations of the 201 Tl scintiscans should be supplemented by quantification methods. Quantification is also required between 201 Tl examination and surgery and to assure constant diagnostic accuracy in case of examination by different examiners. (orig./MG) [de

  19. Detectors for CBA

    International Nuclear Information System (INIS)

    Baggett, N.; Gordon, H.A.; Palmer, R.B.; Tannenbaum, M.J.

    1983-05-01

    We discuss some current approaches to a large solid angle detector. An alternative approach for utilizing the high rate of events at CBA is to design special purpose detectors for specific physics goals which can be pursued within a limited solid angle. In many cases this will be the only way to proceed, and then high luminosity has a different significance. The total rate in the restricted acceptance is less likely to be a problem, while the need for high luminosity to obtain sufficient data is obvious. Eight such experiments from studies carried out in the community are surveyed. Such experiments could be run on their own or in combination with others at the same intersection, or even with a large solid angle detector, if a window can be provided in the larger facility. The small solid angle detector would provide the trigger and special information, while the facility would provide back-up information on the rest of the event. We consider some possibilities of refurbishing existing detectors for use at CBA. This discussion is motivated by the fact that there is a growing number of powerful detectors at colliding beam machines around the world. Their builders have invested considerable amounts of time, money and ingenuity in them, and may wish to extend the useful lives of their creations, as new opportunities arise

  20. Room temperature X- and gamma-ray detectors using thallium bromide crystals

    CERN Document Server

    Hitomi, K; Shoji, T; Suehiro, T; Hiratate, Y

    1999-01-01

    Thallium bromide (TlBr) is a compound semiconductor with wide band gap (2.68 eV) and high X- and gamma-ray stopping power. The TlBr crystals were grown by the horizontal travelling molten zone (TMZ) method using purified material. Two types of room temperature X- and gamma-ray detectors were fabricated from the TlBr crystals: TlBr detectors with high detection efficiency for positron annihilation gamma-ray (511 keV) detection and TlBr detectors with high-energy resolution for low-energy X-ray detection. The detector of the former type demonstrated energy resolution of 56 keV FWHM (11%) for 511 keV gamma-rays. Energy resolution of 1.81 keV FWHM for 5.9 keV was obtained from the detector of the latter type. In order to analyze noise characteristics of the detector-preamplifier assembly, the equivalent noise charge (ENC) was measured as a function of the amplifier shaping time for the high-resolution detector. This analysis shows that parallel white noise and 1/f noise were dominant noise sources in the detector...

  1. [Tl(III)(dota)](-): An Extraordinarily Robust Macrocyclic Complex.

    Science.gov (United States)

    Fodor, Tamás; Bányai, István; Bényei, Attila; Platas-Iglesias, Carlos; Purgel, Mihály; Horváth, Gábor L; Zékány, László; Tircsó, Gyula; Tóth, Imre

    2015-06-01

    The X-ray structure of {C(NH2)3}[Tl(dota)]·H2O shows that the Tl(3+) ion is deeply buried in the macrocyclic cavity of the dota(4-) ligand (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetate) with average Tl-N and Tl-O distances of 2.464 and 2.365 Å, respectively. The metal ion is directly coordinated to the eight donor atoms of the ligand, which results in a twisted square antiprismatic (TSAP') coordination around Tl(3+). A multinuclear (1)H, (13)C, and (205)Tl NMR study combined with DFT calculations confirmed the TSAP' structure of the complex in aqueous solution, which exists as the Λ(λλλλ)/Δ(δδδδ) enantiomeric pair. (205)Tl NMR spectroscopy allowed the protonation constant associated with the protonation of the complex according to [Tl(dota)](-) + H(+) ⇆ [Tl(Hdota)] to be determined, which turned out to be pK(H)Tl(dota) = 1.4 ± 0.1. [Tl(dota)](-) does not react with Br(-), even when using an excess of the anion, but it forms a weak mixed complex with cyanide, [Tl(dota)](-) + CN(-) ⇆ [Tl(dota)(CN)](2-), with an equilibrium constant of Kmix = 6.0 ± 0.8. The dissociation of the [Tl(dota)](-) complex was determined by UV-vis spectrophotometry under acidic conditions using a large excess of Br(-), and it was found to follow proton-assisted kinetics and to take place very slowly (∼10 days), even in 1 M HClO4, with the estimated half-life of the process being in the 10(9) h range at neutral pH. The solution dynamics of [Tl(dota)](-) were investigated using (13)C NMR spectroscopy and DFT calculations. The (13)C NMR spectra recorded at low temperature (272 K) point to C4 symmetry of the complex in solution, which averages to C4v as the temperature increases. This dynamic behavior was attributed to the Λ(λλλλ) ↔ Δ(δδδδ) enantiomerization process, which involves both the inversion of the macrocyclic unit and the rotation of the pendant arms. According to our calculations, the arm-rotation process limits the Λ(λλλλ) ↔

  2. In matrix derivatization of trichloroethylene metabolites in human plasma with methyl chloroformate and their determination by solid-phase microextraction-gas chromatography-electron capture detector.

    Science.gov (United States)

    Mudiam, Mohana Krishna Reddy; Jain, Rajeev; Varshney, Meenu; Ch, Ratnasekhar; Chauhan, Abhishek; Goyal, Sudhir Kumar; Khan, Haider A; Murthy, R C

    2013-04-15

    Trichloroethylene (TCE) is a common industrial chemical that has been widely used as metal degreaser and for many industrial purposes. In humans, TCE is metabolized into dichloroacetic acid (DCA), trichloroacetic acid (TCA) and trichloroethanol (TCOH). A simple and rapid method has been developed for the quantitative determination of TCE metabolites. The procedure involves the in situ derivatization of TCE metabolites with methyl chloroformate (MCF) directly in diluted plasma samples followed by extraction and analysis with solid-phase microextraction (SPME) coupled to gas chromatography-electron capture detector (GC-ECD). Factors which can influence the efficiency of derivatization such as amount of MCF and pyridine (PYR), ratio of water/methanol were optimized. The factors which can affect the extraction efficiencies of SPME were screened using 2(7-4) Placket-Burman Design (PBD). A central composite design (CCD) was then applied to further optimize the most significant factors for optimum SPME extraction. The optimum factors for the SPME extraction were found to be 562.5mg of NaCl, pH at 1 and an extraction time of 22 min. Recoveries and detection limits of all three analytes in plasma were found to be in the range of 92.69-97.55% and 0.036-0.068 μg mL(-1) of plasma, respectively. The correlation coefficients were found to be in the range of 0.990-0.995. The intra- and inter-day precisions for TCE metabolites were found to be in the range of 2.37-4.81% and 5.13-7.61%, respectively. The major advantage of this method is that MCF derivatization allows conversion of TCE metabolites into their methyl esters in very short time (≤30 s) at room temperature directly in the plasma samples, thus makes it a solventless analysis. The method developed was successfully applied to the plasma samples of humans exposed to TCE. Copyright © 2013 Elsevier B.V. All rights reserved.

  3. Current state-of-the-art industrial and research applications using room-temperature CdTe and CdZnTe solid state detectors

    International Nuclear Information System (INIS)

    Eisen, Y.

    1996-01-01

    Improvements of CdTe crystal quality and significant progress in the growth of large ingots of high resistivity CdZnTe material enable the fabrication of larger area detectors in single element form or monolithic arrays. These advances allow for the development of imaging devices of improved spatial resolution for industrial, research and medical applications. CdTe and CdZnTe detectors operate in single photon counting mode or in current mode (charge integrating mode). The paper presents advantages of CdTe and CdZnTe over common scintillator type detectors, but also presents the shortcomings of the former detectors with respect to charge collection which limit the yields of good spectrometers. The paper reviews industrial and research applications utilizing these detectors and in particular describes in detail two imaging systems for security screening and custom inspection. These systems are characterized by large dynamic range and good spatial resolution and are composed of large arrays of CdTe spectrometers and discriminator grade detectors. A wide energy range detector assembly, for astrophysical research of gamma ray bursts composed of CdTe, HgI 2 and CdZnTe spectrometers in two dimensional arrays is also presented. (orig.)

  4. Analysis of metabolic change by Tl-201 SPECT in brain tumors treated with stereotactic radiosurgery

    Energy Technology Data Exchange (ETDEWEB)

    Sugo, Nobuo [Toho Univ., Tokyo (Japan). School of Medicine

    1996-03-01

    The time course for changes in Tl-201 uptake and tumor size was studied correlatively. A total of 24 cases of brain tumors was enrolled in the study. Three detector type scanner, PRISM 3000 was used. SPECT scanning was started 10 min after intravenous administration of 111 MBq of Tl-201, and sequentially repeated every 1 min for 16 min. Tl-201 radioactivity was counted in two regions of interest (ROI). One was an area encircling the tumor, and the other, an area in the contralateral hemisphere that served as control. Tl index (TI) was calculated by this formula: TI=T-C/C, where T is the count in the tumor and C, the count in the control area. The size of a given tumor was represented by its maximum diameter as determined by CT or MRI. The TI and the tumor size were compared before and after radiosurgery. In all cases, a decrease in TI was seen earlier than a reduction in tumor size. Among malignant tumors, the TI decrease took place as early as one week, and rapidly reached the lowest level. On the other hand, in benign tumors, it took as long as 6 to 12 months for the decrease of the TI to be evident; the subsequent was very slow. The difference between malignant and benign tumors of the brain is attributed to the fact that high dose irradiation of the malignant, radiosensitive tumors causes deep disturbances in cell metabolism that lead to cell death. By contrast, irradiation of a benign tumor with low radiosensitivity does not affect the cellular metabolism, but injures the vascular wall, leading to gradual stenosis or obliteration of the vessels in the tumor. These data strongly suggest that the rapid and marked decrease of malignant tumors after stereotactic radiosurgery is the result of a direct injury to the malignant cells, and that the rather slow and insufficient diminution of benign tumors can be attributed to diminished blood supply to the tumor. (author)

  5. Phytotoxicity of thallium (Tl) in culture solution. Pt. 1. Effects of Tl(I) on the growth and heavy metal contents of pea and field bean plants

    Energy Technology Data Exchange (ETDEWEB)

    Poetsch, U; Austenfeld, F A

    1985-01-01

    The effects of TlNO/sub 3/ and Tl(I)EDTA on growth and heavy metal contents of pea plants and field bean plants were compared in hydroponic culture experiments. In the presence of TlNO/sub 3/, the essential heavy metals were available to the plants in their ionic forms. When Tl(I)EDTA was present the essential heavy metals were available as chelated complexes. With increasing concentration of TlNO/sub 3/ dry matter production of pea plants was lowered and the Tl content of each organ was increased. The highest Tl content was found within the stems. The increased Tl contents were accompanied by depressed Mn, Zn, and Cu contents of the roots and depressed Mn contents of the stems, but increased Fe contents of the stems. Substitution of TlNO/sub 3/ by Tl(I)EDTA resulted in a stronger growth inhibition of the pea plants, and higher Tl contents of each organ. The highest Tl content was found within the stems. Tl(I)EDTA depressed Mn in the roots, but increased Fe and Mn in the stems, and Fe, Zn and Cu in the leaves. The increases may due to concentration by growth inhibition. The growth of the field bean was not effected by TlNO/sub 3/ nor by Tl(I)EDTA. The field bean contained most of the Tl within the roots and translocated only relatively small amounts to the shoots. This pattern was independent of the Tl compound. Increasing concentrations of TlNO/sub 3/ resulted in depressed Mn and Zn contents of the roots, and Mn contents of the stems. Chelation of Tl(I) resulted in a decrease of the Tl content of each organ. Tl(I)EDTA depressed only the Mn content of the roots.

  6. The TL and OSL study of hydroxyapatites for dosimetric applications

    International Nuclear Information System (INIS)

    Alencar, Marcus A. Vallim de

    2009-01-01

    The hydroxyapatite, the principal mineral component of the bone and tooth enamel, is one of the dosimetric materials that has distinguished itself in the high dose and accidents dosimetry, as well as in the dating, for the Electron Paramagnetic Resonance (EPR) technique. For this reason, the hydroxyapatite could also be used as Thermoluminescence (TL) and Optically Stimulated Luminescence (OSL) dosimeter in the dosimetry of high doses and accidents, and also in the archaeological and geological dating. This work presents a brief study of the TL and OSL behaviour of the B type synthetic carbonated hydroxyapatite, observing the possibility to use this material in TL and OSL dosimetry. The samples were irradiated to a dose of 100 Gy and 1000 Gy, and the TL and OSL measurements were obtained by the RISOE TL/OSL reader, model TL/OSL-DA-15B. The first results demonstrate the presence of three peaks in the TL glow curve in the temperatures of 100 deg C, 150 deg C and 280 deg C. The synthetic carbonated hydroxyapatite also presents an OSL signal when the sample is stimulated with blue light and a small OSL signal for stimulation with infrared light (IR). These results indicate the possibility of this synthetic carbonated hydroxyapatite to be used as dose indicator material using the TL and OSL techniques. (author)

  7. Leading the Charge for SoTL--Embracing Collaboration

    Science.gov (United States)

    Cassard, Anita; Sloboda, Brian

    2014-01-01

    The scholarship of teaching and learning (SoTL) enables colleges and universities to assess student learning and measure the outcomes by engaging in meaningful research, and to disseminate this research. The objective of this paper is to give a snapshot of and assess the current thinking behind this scholarship by presenting examples of SoTL, and…

  8. Abnormal 201Tl limb scan due to unilateral tremor

    International Nuclear Information System (INIS)

    Simons, M.; Schelstraete, K.; Bratzlavsky, M.

    1982-01-01

    A abnormal intra- and interextremity distribution pattern on 201 Tl was observed on the limb scan of a patient with a unilateral tremor. This is ascribed to the increased blood flow in the muscles responsible for the tremor. The suggestion is made that the existence of tremor should be considered as a possible explanation for unexpected abnormalities on 201 Tl limb scintigrams

  9. Syntheses, crystal structures, and characterization of two new Tl{sup +}-Cu{sup 2+}-Te{sup 6+} oxides: Tl{sub 4}CuTeO{sub 6} and Tl{sub 6}CuTe{sub 2}O{sub 10}

    Energy Technology Data Exchange (ETDEWEB)

    Yeon, Jeongho; Kim, Sang-Hwan [Department of Chemistry, University of Houston, 136 Fleming Building, Houston, TX 77204-5003 (United States); Green, Mark A. [Department of Materials Science and Engineering, University of Maryland, College Park, MD, 20742-2115 and NIST Center for Neutron Research, National Institute of Standard and Technology, 100 Bureau Drive, Gaithersburg, MD 20899-6103 (United States); Bhatti, Kanwal Preet; Leighton, C. [Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455-0132 (United States); Shiv Halasyamani, P., E-mail: psh@uh.edu [Department of Chemistry, University of Houston, 136 Fleming Building, Houston, TX 77204-5003 (United States)

    2012-12-15

    Crystals and polycrystalline powders of two new oxide materials, Tl{sub 4}CuTeO{sub 6} and Tl{sub 6}CuTe{sub 2}O{sub 10}, have been synthesized by hydrothermal and solid-state methods. The materials were structurally characterized by single-crystal X-ray diffraction. Tl{sub 4}CuTeO{sub 6} and Tl{sub 6}CuTe{sub 2}O{sub 10} exhibit one dimensional anionic slabs of [CuTeO{sub 6}]{sup 4-} and [CuTe{sub 2}O{sub 10}]{sup 6-}, respectively. Common to both slabs is the occurrence of Cu{sup 2+}O{sub 4} distorted squares and Te{sup 6+}O{sub 6} octahedra. The slabs are separated by Tl{sup +} cations. For Tl{sub 4}CuTeO{sub 6}, magnetic measurements indicate a maximum at {approx}8 K in the temperature dependence of the susceptibility. Low temperature neutron diffraction data confirm no long-range magnetic ordering occurs and the susceptibility was adequately accounted for by fits to a Heisenberg alternating chain model. For Tl{sub 6}CuTe{sub 2}O{sub 10} on the other hand, magnetic measurements revealed paramagnetism with no evidence of long-range magnetic ordering. Infrared, UV-vis spectra, thermogravimetric, and differential thermal analyses are also reported. Crystal data: Tl{sub 4}CuTeO{sub 6}, Triclinic, space group P-1 (No. 2), a=5.8629(8) A, b=8.7848(11) A, c=9.2572(12) A, {alpha}=66.0460(10), {beta}=74.2010(10), {gamma}=79.254(2), V=417.70(9) A{sup 3}, and Z=2; Tl{sub 6}CuTe{sub 2}O{sub 10}, orthorhombic, space group Pnma (No. 62), a=10.8628(6) A, b=11.4962(7) A, c=10.7238(6) A, V=1339.20(13) A{sup 3}, and Z=4. - Graphical Abstract: Two new oxide materials, Tl{sub 4}CuTeO{sub 6} and Tl{sub 6}CuTe{sub 2}O{sub 10}, have been synthesized and characterized. The materials exhibit one dimensional crystal structures consisting of CuO{sub 4} and TeO{sub 6} polyhedra. Highlights: Black-Right-Pointing-Pointer Two New Tl-Te-Cu-oxides have been synthesized and structurally characterized. Black-Right-Pointing-Pointer For Tl{sub 4}CuTeO{sub 6}, magnetic measurements indicate a

  10. An intercomparison of detectors for measurement of background radiation

    International Nuclear Information System (INIS)

    Nielsen, S.P.; Boetter-Jensen, L.

    1981-04-01

    Measurements of the background radiation were made in 1978 at 14 locations with a high-pressure ionization chamber, thermoluminiscence dosimeters (TLD's), two NaI(Tl) detectors, and a Ge(Li) spectrometer system. Simultaneous measurements with the ionization chamber and the spectrometer system provide reliable estimates of the total background exposure rate, of the individual contributors to the terrestrial exposure rate, and of the exposure rate from the secondary cosmic radiation. The TLD results agree with those of the ionization chamber. The NaI(Tl) detector results show that accurate estimates of the terrestrial exposure rate can be obtained if empirical corrections are applied. (author)

  11. Gamma radiation detectors for safeguards applications

    International Nuclear Information System (INIS)

    Carchon, R.; Moeslinger, M.; Bourva, L.; Bass, C.; Zendel, M.

    2007-01-01

    The IAEA uses extensively a variety of gamma radiation detectors to verify nuclear material. These detectors are part of standardized spectrometry systems: germanium detectors for High-Resolution Gamma Spectrometry (HRGS); Cadmium Zinc Telluride (CZT) detectors for Room Temperature Gamma Spectrometry (RTGS); and NaI(Tl) detectors for Low Resolution Gamma Spectrometry (LRGS). HRGS with high-purity Germanium (HpGe) detectors cooled by liquid nitrogen is widely used in nuclear safeguards to verify the isotopic composition of plutonium or uranium in non-irradiated material. Alternative cooling systems have been evaluated and electrically cooled HpGe detectors show a potential added value, especially for unattended measurements. The spectrometric performance of CZT detectors, their robustness and simplicity are key to the successful verification of irradiated materials. Further development, such as limiting the charge trapping effects in CZT to provide improved sensitivity and energy resolution are discussed. NaI(Tl) detectors have many applications-specifically in hand-held radioisotope identification devices (RID) which are used to detect the presence of radioactive material where a lower resolution is sufficient, as they benefit from a generally higher sensitivity. The Agency is also continuously involved in the review and evaluation of new and emerging technologies in the field of radiation detection such as: Peltier-cooled CdTe detectors; semiconductor detectors operating at room temperature such as HgI 2 and GaAs; and, scintillator detectors using glass fibres or LaBr 3 . A final conclusion, proposing recommendations for future action, is made

  12. ESR and TL age determination of caliche nodules

    Energy Technology Data Exchange (ETDEWEB)

    Oezer, A.M. (Middle East Technical Univ., Ankara (Turkey)); Wieser, A.; Goeksu, H.Y.; Mueller, P.; Regulla, D.F. (Gesellschaft fuer Strahlen- und Umweltforschung mbH Muenchen, Neuherberg (Germany, F.R.). Inst. fuer Strahlenschutz); Erol, O. (Istanbul Univ. (Turkey). School of Geography and Marine Sciences)

    1989-01-01

    Feasibility of dating caliche nodules by ESR and TL is investigated. For both methods the properties of the dating signal are described. Chemical composition as well as TL glow curves of caliches originating from different localities exhibit some differences. Due to the complexity of the TL glow curves, some samples required a special post-annealing procedure in order to resolve the main TL peak for age determination. Typical ESR calcite signals do not exist in caliche, therefore usefulness of the g=2.0040 ESR signal is studied. The results of TL and ESR ages are found to be compatible except for two samples. Possible causes of the discrepancy in these samples are discussed. It is shown that, with proper treatment of the radiation-induced signals, it was possible to date caliche formations older than 350 ka, which is not achievable with other methods like uranium series disequilibrium and/or radiocarbon dating. (author).

  13. ESR and TL age determination of caliche nodules

    International Nuclear Information System (INIS)

    Oezer, A.M.; Wieser, A.; Goeksu, H.Y.; Mueller, P.; Regulla, D.F.; Erol, O.

    1989-01-01

    Feasibility of dating caliche nodules by ESR and TL is investigated. For both methods the properties of the dating signal are described. Chemical composition as well as TL glow curves of caliches originating from different localities exhibit some differences. Due to the complexity of the TL glow curves, some samples required a special post-annealing procedure in order to resolve the main TL peak for age determination. Typical ESR calcite signals do not exist in caliche, therefore usefulness of the g=2.0040 ESR signal is studied. The results of TL and ESR ages are found to be compatible except for two samples. Possible causes of the discrepancy in these samples are discussed. It is shown that, with proper treatment of the radiation-induced signals, it was possible to date caliche formations older than 350 ka, which is not achievable with other methods like uranium series disequilibrium and/or radiocarbon dating. (author)

  14. Ionization detector

    International Nuclear Information System (INIS)

    Steele, D.S.

    1987-01-01

    An ionization detector having an array of detectors has, for example, grounding pads positioned in the spaces between some detectors (data detectors) and other detectors (reference detectors). The grounding pads are kept at zero electric potential, i.e. grounded. The grounding serves to drain away electrons and thereby prevent an unwanted accumulation of charge in the spaces, and cause the electric field lines to be more perpendicular to the detectors in regions near the grounding pads. Alternatively, no empty space is provided there being additional, grounded, detectors provided between the data and reference detectors. (author)

  15. The automated Risoe TL dating reader system

    International Nuclear Information System (INIS)

    Boetter-Jensen, L.

    1988-01-01

    The features of the new modified Riso TL dating reader system are described. A vacuum chamber that accommodates the entire 24-position sample changer unit has been designed. The vacuum and N 2 -gas functions are software-controlled. A newly designed heater system is capable of repeated heating cycles to 700 0 C. The sample changer system accommodates fine-grain discs as well as planchettes for coarse grains. Two software-controlled beta irradiators can be attached to the reader, e.g. for predose measurement. The software allows a user without programming expertise to create any desired measuring sequence, and to store and recall data and glow curves for making analyses. (author)

  16. Evaluasi Pengendalian Sistem Informasi Pengiriman pada TL

    Directory of Open Access Journals (Sweden)

    Nelly Nelly

    2011-06-01

    Full Text Available The purpose of this study is to evaluate the control systems on the TL shipping information, in order to discern weaknesses or problems in delivery of enterprise information systems control using CobIT approach. The research method used is the data collecting by observation, checklists, interviews, and literature study. The results achieved are findings and issue recommendations that provide an illustration about a control of the running information delivery systems. From the illustration it is known that on the company’s control of information delivery system, there are still many things that have not been up to standard. The conclusion obtained is that the control of information delivery systems that have been implemented meets only partially the standards set small, so it still needs much improvement. 

  17. Quality control 201TlCl solution obtained at IPEN-CNEN/SP through the direct method of 201Tl preparation

    International Nuclear Information System (INIS)

    Fernandes, L.; Silva, C.P.G. da.

    1991-09-01

    The radiopharmaceutical 201 TlCl is used in Nuclear medicine for myocardial visualization. The solution of 201 TlCl was prepared using 201 Tl obtained by irradiating a natural mercury target with protons. This radionuclide was subjected to different quality control processes to verify the purity required for its use in Medicine. Some of these controls concerned the determination of 200 Tl, 201 Tl and 202 Tl; the chemical identification of 201 Tl +1 ; the hydrazine concentration, mercury contamination and the presence of phosphate. Furthermore, the biologic distribution in Wistar rats and tests for sterility, pyrogens and for toxicity were carried out. It was verified that the solution obtained was in the form of thallous chloride. This radiopharmaceutical can give a good heart image in animals but due to the contamination of 201 Tl with 200 Tl and 202 Tl its use in human beings is not possible unless enriched 202 Hg is used as target of irradiation. (author)

  18. Growth of InTlSB and InTlP for Long Wavelength Infrared Detector Applications

    National Research Council Canada - National Science Library

    Razeghi, M

    1998-01-01

    .... Other novel alloys such as InAsSb and InSbBi are also investigated. The structural, optical, and electrical properties of these novel materials have been investigated in detail with various ex-situ characterization techniques...

  19. Gamma-ray detectors for intelligent, hand-held radiation monitors

    International Nuclear Information System (INIS)

    Fehlau, P.E.

    1983-01-01

    Small radiation detectors based on HgI 2 , bismuth germanate (BGO), plastic, or NaI(Tl) detector materials were evaluated for use in small, lighweight radiation monitors. The two denser materials, HgI 2 and BGO, had poor resolution at low-energy and thus performed less well than NaI(Tl) in detecting low-energy gamma rays from bare, enriched uranium. The plastic scintillator, a Compton recoil detector, also performed less well at low gamma-ray energy. Two small NaI(Tl) detectors were suitable for detecting bare uranium and sheilded plutonium. One became part of a new lightweight hand-held monitor and the other found uses as a pole-mounted detector for monitoring hard-to-reach locations

  20. Clinical use of 201Tl myocardial scintigraphy

    International Nuclear Information System (INIS)

    Senda, Kohei; Imaeda, Takeyoshi; Kato, Toshimitsu; Asada, Shuichi; Doi, Hidetaka

    1977-01-01

    Myocardial imaging with 201 Tl and scinticamera was studied experimentally using specially designed phantoms and clinically in 23 patients with myocardial infarction or other heart disease. In the phantom experiment, quality of image, accumulative count rate, and detectability of the defect were compared to obtain the best technique for their detection, using four different collimators, i.e., converging, pin-hole, 4000-hole, and 140 keV high-resolution, at two photopeak levels of 201 Tl of 75 and 167 keV, and combining a radiation absorber. In patient examination, myocardial images taken at different periods after injection, different detecting conditions of the scinticamera, and various detecting projections were compared. Images of the converging collimator at the 75 keV photopeak revealed considerably higher accumulative counts and relatively higher quality than those of other detecting conditions. It was necessary to take as many images as possible in various projections, in order to detect the location and size of the myocardial ischemic lesion because the lesion was demonstrated as a clear defect only in profile. It became evident that images taken between about 25 and 90 min delineated the myocardium more clearly than those taken in other periods. Normal images taken in 8 patients without ischemic heart disease appeared in the shape of a doughnut of horseshoe, demonstrating mainly the left venticular myocardium. The image was faint in the region of the aortic or mitral valve and thin in the region of the apical wall. A faint image of the right ventricular myocardium was sometimes seen. In 3 patients with valvular heart disease, findings suggested changes in the thickness of myocardium and the distribution of coronary blood flow. In 11 of 12 patients with old myocardial infarction, the location and size of the lesion was detected. (Evans, J.)