A gamma-gamma coincidence/anticoincidence spectrometer for low-level cosmogenic (22)Na/(7)Be activity ratio measurement.

Science.gov (United States)

Zhang, Weihua; Ungar, Kurt; Stukel, Matthew; Mekarski, Pawel

2014-04-01

In this study, a digital gamma-gamma coincidence/anticoincidence spectrometer was developed and examined for low-level cosmogenic (22)Na and (7)Be in air-filter sample monitoring. The spectrometer consists of two bismuth germanate scintillators (BGO) and an XIA LLC Digital Gamma Finder (DGF)/Pixie-4 software and card package. The spectrometer design allows a more selective measurement of (22)Na with a significant background reduction by gamma-gamma coincidence events processing. Hence, the system provides a more sensitive way to quantify trace amounts of (22)Na than normal high resolution gamma spectrometry providing a critical limit of 3 mBq within a 20 h count. The use of a list-mode data acquisition technique enabled simultaneous determination of (22)Na and (7)Be activity concentrations using a single measurement by coincidence and anticoincidence mode respectively. Copyright © 2014 Elsevier Ltd. All rights reserved.

A new approach to beta-gamma coincidence counting. Advance report on the Samar electronic system

International Nuclear Information System (INIS)

Carlos, J. E. de; Granados, C. E.

1972-01-01

In 4π β-γ coincidence measurements, precision on the evaluation of coincidence counting losses is made difficult because of complex overlapping effects between theβ--and γ-side dead times due to pre cursive counted events. In this context the SAMAR electronic system is aimed to give a precise way of automatic counting and reduce the need for calculated corrections. This report describes its configuration and basic features. The SAMAR has been conceived in such a manner that both beta and gamma chains are sharing a common and non extending dead-time which is simultaneously applied to both channels. The shared dead time is made to be the only one inserted throughout the chains. Overlapping effects vanish and the three counting channels have identical transmission ratios. A new dead-time circuit based on fast linear gates as blocking elements has been developed. Application of the two-oscillator Muller's method evidences a fully non-extending character. Automatism is implemented by using a live timer corrective channel controlling the counting scalers. (Author) 21 refs

Studies on the true coincidence correction in measuring filter samples by gamma spectrometry

CERN Document Server

Lian Qi; Chang Yong Fu; Xia Bing

2002-01-01

The true coincidence correction in measuring filter samples has been studied by high efficiency HPGe gamma detectors. The true coincidence correction for a specific three excited levels de-excitation case has been analyzed, and the typical analytical expressions of true coincidence correction factors have been given. According to the measured relative efficiency on the detector surface with 8 'single' energy gamma emitters and efficiency of filter samples, the peak and total efficiency surfaces are fitted. The true coincidence correction factors of sup 6 sup 0 Co and sup 1 sup 5 sup 2 Eu calculated by the efficiency surfaces agree well with experimental results

A new 4π(LS)-γ coincidence counter at NCBJ RC POLATOM with TDCR detector in the beta channel.

Science.gov (United States)

Ziemek, T; Jęczmieniowski, A; Cacko, D; Broda, R; Lech, E

2016-03-01

A new 4π(LS)-γ coincidence system (TDCRG) was built at the NCBJ RC POLATOM. The counter consists of a TDCR detector in the beta channel and scintillation detector with NaI(Tl) crystal in the gamma channel. The system is equipped with a digital board with FPGA, which records and analyses coincidences in the TDCR detector and coincidences between the beta and gamma channels. The characteristics of the system and a scheme of the FPGA implementation with behavioral simulation are given. The TDCRG counter was validated by activity measurements on (14)C and (60)Co solutions standardized in RC POLATOM using previously validated methods. Copyright © 2015 Elsevier Ltd. All rights reserved.

Beta activity measurements in high, variable gamma backgrounds

International Nuclear Information System (INIS)

Stanga, D.; Sandu, E.; Craciun, L.

1997-01-01

In many cases beta activity measurements must be performed in high and variable gamma backgrounds. In such instances it is necessary to use well-shielded detectors but this technique is limited to laboratory equipment and frequently insufficient. In order to perform in a simple manner beta activity measurements in high and variable backgrounds a software-aided counting technique have been developed and a counting system have been constructed. This technique combines the different counting techniques with traditional method of successive measurement of the sample and background. The counting system is based on a programmable multi-scaler which is endowed with appropriate software and allow all operations to be performed via keyboard in an interactive fashion. Two large - area proportional detectors were selected in order to have the same background and the same gamma response within 5%. A program has been developed for the counting data analysis and beta activity computing. The software-aided counting technique has been implemented for beta activity measurement in high and variable backgrounds. (authors)

Application of Monte Carlo method in study of the padronization for radionuclides with complex disintegration scheme in 4{pi}{beta}-{gamma} coincidence System; Aplicacao do metodo de Monte Carlo no estudo da padronizacao de radionuclideos com esquema de desintegracao complexos em sistema de coincidencias 4{pi}{beta}-{gamma}

Energy Technology Data Exchange (ETDEWEB)

Takeda, Mauro Noriaki

2006-07-01

The present work described a new methodology for modelling the behaviour of the activity in a 4{pi}{beta}-{gamma} coincidence system. The detection efficiency for electrons in the proportional counter and gamma radiation in the NaI(Tl) detector was calculated using the Monte Carlo program MCNP4C. Another Monte Carlo code was developed which follows the path in the disintegration scheme from the initial state of the precursor radionuclide, until the ground state of the daughter nucleus. Every step of the disintegration scheme is sorted by random numbers taking into account the probabilities of all {beta}{sup -} branches, electronic capture branches, transitions probabilities and internal conversion coefficients. Once the final state was reached beta, electronic capture events and gamma transitions are accounted for the three spectra: beta, gamma and coincidence variation in the beta efficiency was performed simulating energy cut off or use of absorbers (Collodion). The selected radionuclides for simulation were: {sup 134}Cs, {sup 72}Ga which disintegrate by {beta}{sup -} transition, {sup 133}Ba which disintegrates by electronic capture and {sup 35}S which is a beta pure emitter. For the latter, the Efficiency Tracing technique was simulated. The extrapolation curves obtained by Monte Carlo were filled by the Least Square Method with the experimental points and the results were compared to the Linear Extrapolation method. (author)

Determination of 131mXe and 133mXe in the presence of 133gXe via combined beta-spectroscopy and delayed coincidence

International Nuclear Information System (INIS)

Reeder, P.L.; Bowyer, T.W.; McIntyre, J.I.; Pitts, W.K.

2001-01-01

The International Monitoring System for the Comprehensive Nuclear-Test-Ban Treaty will include measurements of Xe fission products. Pacific Northwest National Laboratory has developed an automated system for separating Xe from air which detects Xe fission products using a beta-gamma counting system for 131m Xe, 133m Xe, 133g Xe, and 135g Xe. Betas and conversion electrons are detected in a plastic scintillation cell containing the Xe sample. Gamma and X-rays are detected in a NaI(Tl) scintillation detector which surrounds the plastic scintillator sample cell. Two-dimensional pulse-height spectra of gamma-energy versus beta-energy are obtained. The plastic scintillator spectrum in coincidence with the 31-keV X-rays from 131m Xe. 133m Xe, and 133g Xe is a complex mixture of conversion electrons and betas. A new technique to simultaneously measure the delayed coincidence (T 1/2 = 6.27 ns) between beta-particles from 133g Xe and conversion electrons depopulating the 81-keV state in 133 Cs is being developed. This technique allows separation of the 133g Xe beta spectrum from the conversion electrons due to 131m Xe and 133m Xe and uniquely quantifies all three nuclides. (author)

Determination of 131m Xe and 133m Xe in the presence of 133gXe via combined beta-spectroscopy and delayed coincidence

International Nuclear Information System (INIS)

Reeder, Paul L.; Bowyer, Ted W.; McIntyre, Justin I.; Pitts, W K.

2001-01-01

The International Monitoring System for the Comprehensive Nuclear-Test-Ban Treaty will include measurements of Xe fission products. Pacific Northwest National Laboratory has developed an automated system for separating Xe from air which detects Xe fission products using a beta-gamma counting system for 131mXe, 133mXe, 133Xe, and 135Xe. Betas and conversion electrons are detected in a plastic scintillation cell containing the Xe sample. Gamma and X-rays are detected in a NaI(Tl) scintillation detector which surrounds the plastic scintillator sample cell. Two-dimensional pulse height spectra of gamma energy versus beta energy are obtained. The plastic scintillator spectrum in coincidence with the 31-keV X-rays from 131mXe. 133mXe, and 133Xe is a complex mixture of conversion electrons and betas. A new technique to simultaneously measure the delayed coincidence (t1/2 = 6.27 ns) between beta particles from 133Xe and conversion electrons depopulating the 81-keV state in 133Cs is being developed. This technique will allow separation of the 133Xe spectrum from the conversion electrons due to 131mXe and 133mXe and will uniquely quantify all three nuclides

Beta-gamma counting system for Xe fission products

International Nuclear Information System (INIS)

Reeder, P.L.; Bowyer, T.W.; Perkins, R.W.

1998-01-01

A beta-gamma coincidence counting system has been developed for automated analysis of Xe gas samples separated from air. The Xe gas samples are contained in a cylindrical plastic scintillator cell located between two NaI(Tl) scintillation detectors. The X-ray and gamma spectra gated by coincident events in the plastic scintillator cell are recorded for each NaI(Tl) crystal. The characteristic signatures of the 131m Xe, 133g Xe, 133m Xe, and 135g Xe isotopes of interest for nuclear test-ban verification as well as the procedures and results of absolute efficiency measurements are described. A NaI(Tl) crystal with provision for 4 sample cells has been implemented for the system to be deployed in the field. Examples of data on ambient air samples in New York City obtained with the field prototype are presented. (author)

Advanced Time-Delayed Coincidence Studies of $^{31,32}$Mg from the $\\beta$-decays of $^{31,32}$Na

CERN Multimedia

Marechal, F; Plociennik, W A

2002-01-01

It is proposed to study the lifetime of the 2$_{1}^{+}$ 885.4 keV state in $^{32}$Mg by means of Advanced Time-Delayed $\\beta \\gamma \\gamma$(t) method with the precision in the half-life value of about $\\pm$ 1.5 ps. This would be an independent verification of the B(E2; 0$_{1}^{+} \\rightarrow$ 2$_{1}^{+}$) values obtained so far in a few studies using Coulomb excitations at intermediate beam energies. The advantage of time-delayed coincidence measurements is that they are free of corrections used in the Coulex studies, which strongly affect the deduced B(E2) results. In addition, we propose to study the lifetimes or lifetime limits of other states in nuclei populated in the decays of $^{31}$Na and $^{32}$Na, specifically focusing on the intruder negative parity band in $^{31}$Mg. As a side benefit to this investigation we expect high-quality $\\gamma \\gamma$ coincidences to reveal new excited states in both $^{31}$Mg and $^{32}$Mg. Our results from a brief test-measurement yield a lifetime of T$_{1/2}$ = 10.5(...

Development of Coincidence Method for Determination Thermal Neutron Flux on RSG-GAS

International Nuclear Information System (INIS)

Bakhri, Syaiful; Hamzah, Amir

2004-01-01

The research to develop detection radiation system using coincidence method has been done to determine thermal neutron flux in RS1 and RS2 irradiation facilities RSG-GAS. At this research has arranged beta-gamma coincidence equipment system and parameter of measurement according to Au-198 beta-gamma spectrum. Gold foils that have irradiated for period of time, counted, and the activities of radiation is analyzed to get neutron flux. Result of research indicate that systems measurement of absolute activity with gamma beta coincidence method functioning well and can be applied at activity measurement of gold foil for irradiation facility characterization. The results show that thermal neutron flux in RS1 and RS2, respectively is 2.007E+12 n/cm 2 s and 2.147E+12 n/cm 2 s. To examine the system performance, the result was compared to measure activity using high resolution of Hp Ge detector and achieved discrepancy is about 1.26% and 6.70%. (author)

Measurement of Q{sub {beta}} values of neutron-rich Tc to Pd isotopes in the mass range A=110 to A=117; Messung von Q{sub {beta}}-Werten neutronenreicher Tc- bis Pd-Isotope im Massenbereich A=110 bis A=117

Energy Technology Data Exchange (ETDEWEB)

Kloeckl, Ingo

2008-06-15

The present work describes the measuring of Q{sub {beta}} values of {beta}-instable isotopes of Tc, Ru, Rh and Pd. The mass range A=110 to 117 comprises neutron-rich, short-living isotopes. Due to their small (fission) abundances, few data are known, especially regarding level schemes or gamma radiation. The proton-induced fission and a fast online mass separation was used to produce these nuclides in the IGISOL facility located in Jyvaeskylaein Finland. The {beta},{gamma},X coincidence apparatus used during the experiments allows measuring Q{sub {beta}} values as well as {gamma},X coincidences. The latter represent the basic input data for a calculation of Q{sub {beta}} values out of {beta},{gamma} coincidences. It is so possible to examine nuclides with incomplete level schemes; similarly, these level schemes can be extended using beta,gamma coincidence data. Twelve Q{sub {beta}} values of neutron-rich Tc to Pd isotopes could be determined, yielding nuclear masses, mass defects and neutron separation energies. Eight of them were determined for the first time; another one could be confirmed. For three more, the error of earlier values could be decreased by a factor of nearly ten. The resulting data are of interest for the review of nuclear mass models, they represent also input in astrophysical network calculations. (orig.)

Studies of weak capture-gamma-ray resonances via coincidence techniques

CERN Document Server

Rowland, C; Champagne, A E; Dummer, A K; Fitzgerald, R; Harley, E C T; Mosher, J; Runkle, R

2002-01-01

A method for measuring weak capture-gamma-ray resonances via gamma gamma-coincidence counting techniques is described. The coincidence apparatus consisted of a large-volume germanium detector and an annular NaI(Tl) crystal. The setup was tested by measuring the weak E sub R =227 keV resonance in sup 2 sup 6 Mg(p,gamma) sup 2 sup 7 Al. Absolute germanium and NaI(Tl) counting efficiencies for a range of gamma-ray energies and for different detector-target geometries are presented. Studies of the gamma-ray background in our spectra are described. Compared to previous work, our method improves the detection sensitivity for weak capture-gamma-ray resonances by a factor of approx 100. The usefulness of the present technique for investigations of interest to nuclear astrophysics is discussed.

Mass measurement project by determination of Q{sub {beta}} for neutron-rich nuclei; Projet de mesure des masses par determination des Q{sub {beta}} pour des noyaux tres riches en neutrons

Energy Technology Data Exchange (ETDEWEB)

Pautrat, M; Lagrange, J M; Petizon, L [Paris-11 Univ., 91 - Orsay (France). Inst. de Physique Nucleaire; Vanhorenbeeck, J; Duhamel, P [Brussels Univ. (Belgium). Inst. d` Astronomie et d` Astrophysique; Binon, F [Universite Libre de Bruxelles (Belgium)

1994-12-31

The aim of the project described hereafter is to collect new data on the exotic neutron rich nuclei of the Fe to Zn region, and in particular to determine their masses, for both nuclear physics and astrophysics purposes. These isotopes will be produced through projectile fragmentation at the GANIL facility and selected by the LISE3 spectrometer. Their half-lives will be measured as well as the energy of their main {gamma} rays; {gamma} - {gamma} coincidences will then allow to build a preliminary level scheme. The analysis of {beta} spectra and {beta} - {gamma} coincidences will finally provide the maximum {beta} decay energies of the studied nuclei leading to their masses. The difficulties arising from the low production rates, the {beta} detection, the data handling are discussed together with the solutions proposed to overcome them. (authors). 17 refs.

Low level radioactivity measurements with phoswich detectors using coincident techniques and digital pulse processing analysis.

Science.gov (United States)

de la Fuente, R; de Celis, B; del Canto, V; Lumbreras, J M; de Celis Alonso, B; Martín-Martín, A; Gutierrez-Villanueva, J L

2008-10-01

A new system has been developed for the detection of low radioactivity levels of fission products and actinides using coincidence techniques. The device combines a phoswich detector for alpha/beta/gamma-ray recognition with a fast digital card for electronic pulse analysis. The phoswich can be used in a coincident mode by identifying the composed signal produced by the simultaneous detection of alpha/beta particles and X-rays/gamma particles. The technique of coincidences with phoswich detectors was proposed recently to verify the Nuclear Test Ban Treaty (NTBT) which established the necessity of monitoring low levels of gaseous fission products produced by underground nuclear explosions. With the device proposed here it is possible to identify the coincidence events and determine the energy and type of coincident particles. The sensitivity of the system has been improved by employing liquid scintillators and a high resolution low energy germanium detector. In this case it is possible to identify simultaneously by alpha/gamma coincidence transuranic nuclides present in environmental samples without necessity of performing radiochemical separation. The minimum detectable activity was estimated to be 0.01 Bq kg(-1) for 0.1 kg of soil and 1000 min counting.

Elaboration of Co-60 sources on gilding vyns, with beta efficiencies 80 % or better and its activity measure by the coincidences method; Elaboracion de fuentes de Co-60 sobre vyns dorado, con eficiencias beta del 80 % o mejor y su medida de actividad por el metodo de coincidencias

Energy Technology Data Exchange (ETDEWEB)

Cortes P, A.; Tejera R, A.; Becerril V, A.; Ortiz C, A

1991-12-15

The measuring technique of radioactive activity by the coincidences method 4 {pi} {beta}{sup -} {gamma} it requires of the elaboration of radioactive sources on thin supports in order to flows the biggest percentage of beta particles, those of the order of the 80 % or but. In this work a procedure for the elaboration of this type of sources, with gilding Vyns is reported. (Author)

Instruments used to measure or check {alpha}, {beta}, {gamma} activity and neutron emission in the course of processing ore or irradiated fuel; Appareils de mesure ou de controle {alpha}, {beta}, {gamma}, n, des circuits des usines de traitement du minerai ou du combustible irradie

Energy Technology Data Exchange (ETDEWEB)

Blanc, A; Brunet, M; Kermagoret, M; Labeyrie, J; Roux, G; Vasseur, J; Weil, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1959-07-01

One of the methods checking ores in the course of treatment is the rapid quantitative determination of thorium. This measurement is carried out by means of a scintillation instrument which shows the {beta} and {alpha} coincidences of ThC and ThC'. The treatment of irradiated fuel is accompanied by a large number of radioactive checks relative to the performance of the fixation and elution operations of uranium in the ion exchangers, to the concentration of radioactivity of effluent sent from the plant into watercourses. The operations of fixation and elution of the uranium are checked automatically by an instrument which takes a sample of 5 cm{sup 3} of solution, evaporates it and measures its activity every 10 or 20 minutes. Plutonium concentrations are measured: - in the presence of strong {beta} {gamma} activities, by means of rotating cylinder detectors; - in the presence of weak {beta} {gamma} activities, by means of {alpha} detectors scanning a constant level liquid surface; - by means of fission chambers relatively insensitive to {gamma}. Fission product concentrations are measured by chambers, counters or scintillators, according to the amount of {gamma} activity present. Finally, the activity of effluent to be emptied into watercourses is checked by means of a scintillation instrument, which measures the {alpha} activity on the one hand, and on the other hand the {beta} {gamma} activity of residue from a 100 cm{sup 3} sample taken and evaporated in 20 minutes. (author) [French] Parmi les controles relatifs au minerai en cours de traitement, figure le dosage rapide de thorium. Cette mesure est realisee au moyen d'un appareillage a scintillation qui met en evidence la coincidence des emissions {beta} et {alpha} du ThC et du ThC'. Le traitement des combustibles irradies s'accompagne d'un grand nombre de controles radioactifs portant sur le fonctionnement des operations de fixation et d'elution de l'uranium dans les echangeurs d'ions, sur la concentration du

Study and development of a spectrometer with Compton suppression and gamma coincidence counting

International Nuclear Information System (INIS)

Masse, D.

1990-10-01

This paper presents the characteristics of a spectrometer consisting of a Ge detector surrounded by a NaI(T1) detector that can operate in Compton-suppression and gamma-gamma coincidence modes. The criteria that led to this measurement configuration are discussed and the spectrometer performances are shown for 60 Co and 137 Cs gamma-ray sources. The results for the measurement of 189 Ir (Compton suppression) and for the measurement of 101 Rh (gamma-gamma coincidence) in the presence of other radioisotopes are given. 83 Rb and 105 Ag isotopes are also measured with this spectrometer [fr

Identification of peaks in multidimensional coincidence {gamma}-ray spectra

Energy Technology Data Exchange (ETDEWEB)

Morhac, Miroslav E-mail: fyzimiro@savba.sk; Kliman, Jan; Matousek, Vladislav; Veselsky, Martin; Turzo, Ivan

2000-03-21

In the paper a new algorithm to find peaks in two, three and multidimensional spectra, measured in large multidetector {gamma}-ray arrays, is derived. Given the dimension m, the algorithm is selective to m-fold coincidence peaks. It is insensitive to intersections of lower-fold coincidences, hereinafter called ridges.

A method for measuring the energy spectrum of coincidence events in positron emission tomography.

Science.gov (United States)

Goertzen, Andrew L; Stout, David B; Thompson, Christopher J

2010-01-21

Positron emission tomography (PET) system energy response is typically characterized in singles detection mode, yet there are situations in which the energy spectrum of coincidence events might be different than the spectrum measured in singles mode. Examples include imaging with isotopes that emit a prompt gamma in coincidence with a positron emission, imaging with low activity in a LSO/LYSO-based cameras, in which the intrinsic activity is significant, and in high scatter situations where the two 511 keV photons have different scattering probabilities (i.e. off-center line source). The ability to accurately measure the energy spectrum of coincidence events could be used for validating simulation models, optimizing energy discriminator levels and examining scatter models and corrections. For many PET systems operating in coincidence mode, the only method available for estimating the energy spectrum is to step the lower and upper level discriminators (LLD and ULD). Simple measurement techniques such as using a narrow sliding energy window or stepping only the LLD will not yield a spectrum of coincidence events that is accurate for cases where there are different energy components contributing to the spectrum. In this work we propose a new method of measuring the energy spectrum of coincidence events in PET based on a linear combination of two sets of coincident count measurements: one made by stepping the LLD and one made by stepping the ULD. The method was tested using both Monte Carlo simulations of a Siemens microPET R4 camera and measured data acquired on a Siemens Inveon PET camera. The results show that our energy spectrum calculation method accurately measures the coincident energy spectra for cases including the beta/gamma spectrum of the (176)Lu intrinsic activity present in the LSO scintillator crystals, a (68)Ge source and an (124)I source (in which there are prompt gamma-rays emitted together with the positron).

Operations manual for the megachannel gamma-ray coincidence system

International Nuclear Information System (INIS)

Ruhter, W.

1977-01-01

To aid in the study of nuclear structures, a megachannel pulse-height coincidence analysis system on a PDP-8 computer was constructed. The system digitizes the energies of coincident gamma-rays and stores the resultant information on a moving-head disk. The system uses a minicomputer to sort and store gamma-gamma coincident information on line. The megachannel system and how to use it are described

4{pi} proportional counter for absolute measurement of {beta}-emitters; Compteur 4{pi} proportionnel destine a la mesure absolue d'emetteurs {beta}

Energy Technology Data Exchange (ETDEWEB)

Perolat, J P; Laine, M [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1967-07-01

The 4{pi} counter is commonly used to measure the activity of {beta} sources, the one we describe does not advance a new conception but the issue of several years of investigations. The apparatus presents good performances about the qualities commonly required in that kind of counter: detection efficiency, plateau and dead time. Moreover technical characteristics give a great flexibility in use, particularly a possibility of adaptation in a {beta},{gamma} coincidence unit. (authors) [French] Le compteur 4{pi} proportionnel est couramment, utilise pour mesurer l'activite de sources {beta}, celui que nous decrivons ne represente pas une conception nouvelle, mais plutot l'aboutissement de plusieurs annees d'etudes. Cette installation presente des performances satisfaisantes en ce qui concerne les qualites habituellement requises dans ce type de compteur: l'efficacite de detection, le palier et le temps mort. En outre, certaines caracteristiques techniques qui lui sont propres lui conferent une grande souplesse d'utilisation, en particulier la possibilite d'adaptation a un ensemble de mesures par coincidences 4{pi} {beta} {gamma}. (auteurs)

Reduction of beta-interference in gamma-spectrometric measurements of neutron-irradiated geological material

International Nuclear Information System (INIS)

Garmann, L.B.

1986-01-01

The analytical technique for INAA, when applied to geological materials, is improved by introducing an electromagnetic field between sample and detector. This field lowers the bremsstrahlung background intensity in the gamma-spectrum by reducing the number of beta-particles reaching the detector. Thus precision, accuracy and lower detection limit are improved. The technique was used on alkalisyenite and on meteoritic material, rocks containing high quantities of sodium and iron, respectively. After neutron irradiation, the induced nuclides sup(24)Na and sup(59)Fe are responsible for high bremsstrahlung interference, which under normal analyitical conditions would mask any x-ray or gamma-ray peaks of interest. The technique is easily applied to multielement analysis of geological and biological materials. It can be combined with sophisticated spectrum-treating techniques such as spectrum stripping and spectrum smoothing, or coincidence-anticoincidence circuits. (author)

Study and construction of a {beta}-spectrometer of uniform axial magnetic field fitted with a {beta}-{gamma} coincidence selector. Study of the {beta} spectra of {sup 32}P, {sup 203}Hg, {sup 198}Au. Measurement of the conversion coefficients of {sup 203}Ti and of {sup 198}Hg; Etude et realisation d'un spectrometre-{beta} a champ magnetique axial uniforme, muni d'un selecteur de coincidence {beta}-{gamma}. Etude des spectres {beta} du {sup 32}p, {sup 203}Hg, {sup 198}Au. Mesure des coefficients de conversion du {sup 203}Ti et du {sup 198}Hg

Energy Technology Data Exchange (ETDEWEB)

Parsignault, D [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1964-06-01

In the first part is given the principle of the beta spectrometer with uniform axial field using systematically the idea of caustics. The apparatus is described and its properties compared to those deduced from trajectory calculations. The {beta}-ray and {gamma}-ray detectors and the device for selecting coincidences with a 2 {tau} resolution of 5 nanoseconds are also presented. In the second part, the spectrometer is used for studying reference elements and the most accurate results are confirmed. The {beta} spectrum of {sup 60}Co has a statistical form with an accuracy of 1 per cent; the maximum energy E{sub 0} is 316.5 {+-} 1.5 keV. That of the 7/2 + {yields} 11/2 transition for {sup 137}Cs has a unique form, once forbidden. E{sub 0}= 522 {+-} 3 keV. Conversion coefficients {alpha}{sub k} = 96 {+-} 1 X 10{sup -3} {alpha}L + M + N = 20.9 {+-} 0.5 X 10{sup -3}. The two {beta} spectra of {sup 59}Fe, separated by coincidence with the gamma, have the statistical form E{sub 0} = 462 {+-} 2 keV (55.1 + 0,3 per cent) and E{sub 1} = 275 {+-} 4 keV (44.9 {+-} 0.3 per cent). It is then verified whether the l selection rule is apparent in the shape of the phosphorus 32 beta spectrum. It is found in fact that it is not of statistical shape and its shape coefficient is determined. For a theoretical interpretation it is necessary to have better approximations than those generally used and this interpretation will not be unique. This work has also made it possible to show that the source contains a small proportion of {sup 33}P. The study of the {sup 203}Hg {beta} spectrum followed by the 279 keV gamma spectrum is designed to determine the conversion coefficients. The interior spectrum of gold 198 is not of statistical shape either. The form coefficient is determined together with the conversion coefficients which are in slight disagreement with those calculated by Rose or Sliv. An interpretation of the spectrum is put forward which proposes an imperfect compensation for the

Study and construction of a {beta}-spectrometer of uniform axial magnetic field fitted with a {beta}-{gamma} coincidence selector. Study of the {beta} spectra of {sup 32}P, {sup 203}Hg, {sup 198}Au. Measurement of the conversion coefficients of {sup 203}Ti and of {sup 198}Hg; Etude et realisation d'un spectrometre-{beta} a champ magnetique axial uniforme, muni d'un selecteur de coincidence {beta}-{gamma}. Etude des spectres {beta} du {sup 32}p, {sup 203}Hg, {sup 198}Au. Mesure des coefficients de conversion du {sup 203}Ti et du {sup 198}Hg

Energy Technology Data Exchange (ETDEWEB)

Parsignault, D. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1964-06-01

In the first part is given the principle of the beta spectrometer with uniform axial field using systematically the idea of caustics. The apparatus is described and its properties compared to those deduced from trajectory calculations. The {beta}-ray and {gamma}-ray detectors and the device for selecting coincidences with a 2 {tau} resolution of 5 nanoseconds are also presented. In the second part, the spectrometer is used for studying reference elements and the most accurate results are confirmed. The {beta} spectrum of {sup 60}Co has a statistical form with an accuracy of 1 per cent; the maximum energy E{sub 0} is 316.5 {+-} 1.5 keV. That of the 7/2 + {yields} 11/2 transition for {sup 137}Cs has a unique form, once forbidden. E{sub 0}= 522 {+-} 3 keV. Conversion coefficients {alpha}{sub k} = 96 {+-} 1 X 10{sup -3} {alpha}L + M + N = 20.9 {+-} 0.5 X 10{sup -3}. The two {beta} spectra of {sup 59}Fe, separated by coincidence with the gamma, have the statistical form E{sub 0} = 462 {+-} 2 keV (55.1 + 0,3 per cent) and E{sub 1} = 275 {+-} 4 keV (44.9 {+-} 0.3 per cent). It is then verified whether the l selection rule is apparent in the shape of the phosphorus 32 beta spectrum. It is found in fact that it is not of statistical shape and its shape coefficient is determined. For a theoretical interpretation it is necessary to have better approximations than those generally used and this interpretation will not be unique. This work has also made it possible to show that the source contains a small proportion of {sup 33}P. The study of the {sup 203}Hg {beta} spectrum followed by the 279 keV gamma spectrum is designed to determine the conversion coefficients. The interior spectrum of gold 198 is not of statistical shape either. The form coefficient is determined together with the conversion coefficients which are in slight disagreement with those calculated by Rose or Sliv. An interpretation of the spectrum is put forward which proposes an imperfect compensation for the

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.

Use of sum-peak and coincidence counting methods for activity standardization of {sup 22}Na

Energy Technology Data Exchange (ETDEWEB)

Oliveira, E.M. de, E-mail: estela@ird.gov.br [Laboratorio Nacional de Metrologia das Radiacoes Ionizantes (LNMRI/IRD/CNEN), Av. Salvador Allende, s/n, Recreio, CEP 22780-160 Rio de Janeiro (Brazil); Iwahara, A.; Poledna, R. [Laboratorio Nacional de Metrologia das Radiacoes Ionizantes (LNMRI/IRD/CNEN), Av. Salvador Allende, s/n, Recreio, CEP 22780-160 Rio de Janeiro (Brazil); Silva, M.A.L. da [Coordenacao Geral de Instalacoes Nucleares/Comissao Nacional de Energia Nuclear, R. Gal. Severiano, 90 - Botafogo, CEP 22290-901 Rio de Janeiro (Brazil); Tauhata, L. [Fundacao Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro (FAPERJ), Av. Erasmo Braga, 118-6 Degree-Sign andar, CEP 20020-000 Centro, Rio de Janeiro (Brazil); Delgado, J.U. [Laboratorio Nacional de Metrologia das Radiacoes Ionizantes (LNMRI/IRD/CNEN), Av. Salvador Allende, s/n, Recreio, CEP 22780-160 Rio de Janeiro (Brazil); Lopes, R.T. [Laboratorio de Instrumentacao Nuclear (LIN/PEN/COPPE/UFRJ), Caixa Postal 68509, CEP 21945-970 Rio de Janeiro (Brazil)

2012-09-21

A solution containing the positron emitter {sup 22}Na has been absolutely standardized using the 4{pi}{beta}-{gamma} coincidence counting method and the sum-peak spectrometry counting method. In the 4{pi}{beta}-{gamma} coincidence method two ways for the activity concentration measurements were used: gating on the 1275 keV photopeak and on the 1786 keV sum-peak where the knowledge of the {beta}{sup +}-branching ratio is required. In the sum-peak method the measurements were carried out using three experimental arrangements: the first composed by a well type 5 in. Multiplication-Sign 5 in. NaI(Tl) scintillation crystal, the second by a 3 in. Multiplication-Sign 3 in. NaI(Tl) scintillation crystal placed on the top of the first, resulting in a 4{pi} counting geometry and the third arrangement is a high purity coaxial germanium detector. The results that are obtained by these two methods are compatible within the standard uncertainty values with a coverage factor of k=2 ({approx}95% of the confidence level). This means that the sum-peak counting with its more simple experimental setup than the complex coincidence 4{pi}{beta}-{gamma} counting system gives consistent results for the activity standardization of {sup 22}Na with smaller uncertainties. Besides, the time period involved to attain the result of the standardization was quite shorter than the coincidence measurements used in this work.

Absolute 22Na radioactivity measurement by gamma efficiency variation of 4πβ-γ coincidence method

International Nuclear Information System (INIS)

Hino, Yoshio; Kawada, Yasusi.

1994-01-01

The absolute radioactivity of 22 Na was obtained by gamma efficiency variation of 4πβ-γ coincidence method. Some other previous techniques, such as sum peak gate method based on the positron emission rate, relative measurement with calibrated ionization chambers, and gamma spectrometry with a HPGe detector, were also tried to ensure the present result. The results of these methods were in reasonable agreement with the present absolute measurement. The assayed source solution of this experiment was transferred to NBS type ampoules, and sealed ampoules were sent to the SIR (International Reference System) in BIPM, Taiwan and Indonesia for the international comparison. (author)

Maternal plasma concentrations of beta-lipotrophin, beta-endorphin and gamma-lipotrophin throughout pregnancy.

Science.gov (United States)

Browning, A J; Butt, W R; Lynch, S S; Shakespear, R A

1983-12-01

Plasma beta-LPH, beta-EP and gamma-LPH concentrations were measured by radioimmunoassay in 10 pregnant women from 12 weeks gestation until term and in nine women in the early follicular phase of the cycle. There was a progressive and significant rise in the concentration of all three peptides throughout pregnancy and by 32 weeks the concentrations of beta-LPH and beta-EP were greater than the corresponding concentrations in the follicular phase: gamma-LPH was greater than in the follicular phase by the end of pregnancy in those women who were delivered after 40 weeks. The ratio of beta-LPH to gamma-LPH did not change significantly throughout pregnancy, but there was a progressive fall in the beta-LPH/beta-EP ratio. The possible presence of a 'big LPH' to explain this finding is discussed.

Preliminary results of a neutron-gamma coincidence experiment

International Nuclear Information System (INIS)

Piercey, R.B.; Dunnam, F.E.; Muga, M.L.; Rester, A.C.; Ramayya, A.V.; Hamilton, J.H.; Eberth, J.; Zganjar, E.F.

1984-01-01

The recently completed neutron multiplicity detector dubbed PANDA (Pentagonal Annular Neutron Detector Array) is fully described later in this report. The new detector was recently used for the first time on-line at the Holifield Heavy Ion Research Facility to measure neutron-gamma coincidence in the 24 Mg( 58 Ni,xαypzn) reaction. The detector configuration for the experiment is shown. The PANDA was situated in the forward direction, coaxial to the beam line with five gamma-ray detectors placed at +/- 90 0 , +/- 135 0 , and 0 0 . 2 figures

Microscopic beta and gamma data for decay-heat needs

International Nuclear Information System (INIS)

Dickens, J.K.

1983-01-01

Microscopic beta and gamma data for decay-heat needs are defined as absolute-intensity spectral distributions of beta and gamma rays following radioactive decay of radionuclides created by, or following, the fission process. Four well-known evaluated data files, namely the US ENDF/B-V, the UK UKFPDD-2, the French BDN (for fission products), and the Japanese JNDC Nuclear Data Library, are reviewed. Comments regarding the analyses of experimental data (particularly gamma-ray data) are given; the need for complete beta-ray spectral measurements is emphasized. Suggestions on goals for near-term future experimental measurements are presented. 34 references

Simultaneous beta and gamma spectroscopy

Science.gov (United States)

Farsoni, Abdollah T.; Hamby, David M.

2010-03-23

A phoswich radiation detector for simultaneous spectroscopy of beta rays and gamma rays includes three scintillators with different decay time characteristics. Two of the three scintillators are used for beta detection and the third scintillator is used for gamma detection. A pulse induced by an interaction of radiation with the detector is digitally analyzed to classify the type of event as beta, gamma, or unknown. A pulse is classified as a beta event if the pulse originated from just the first scintillator alone or from just the first and the second scintillator. A pulse from just the third scintillator is recorded as gamma event. Other pulses are rejected as unknown events.

Production of beta-gamma coincidence spectra of individual radioxenon isotopes for improved analysis of nuclear explosion monitoring data

Science.gov (United States)

Haas, Derek Anderson

Radioactive xenon gas is a fission product released in the detonation of nuclear devices that can be detected in atmospheric samples far from the detonation site. In order to improve the capabilities of radioxenon detection systems, this work produces beta-gamma coincidence spectra of individual isotopes of radioxenon. Previous methods of radioxenon production consisted of the removal of mixed isotope samples of radioxenon gas released from fission of contained fissile materials such as 235U. In order to produce individual samples of the gas, isotopically enriched stable xenon gas is irradiated with neutrons. The detection of the individual isotopes is also modeled using Monte Carlo simulations to produce spectra. The experiment shows that samples of 131mXe, 133 Xe, and 135Xe with a purity greater than 99% can be produced, and that a sample of 133mXe can be produced with a relatively low amount of 133Xe background. These spectra are compared to models and used as essential library data for the Spectral Deconvolution Analysis Tool (SDAT) to analyze atmospheric samples of radioxenon for evidence of nuclear events.

Absolute disintegration rate and 320 keV {gamma}-ray emission probability of {sup 51}Cr

Energy Technology Data Exchange (ETDEWEB)

Almeida, M.C.M. de [Laboratorio Nacional de Metrologia das Radiacoes Ionizantes /Instituto de Radioprotecao e Dosimetria (LNMRI/ IRD), Avenida Salvador Allende, s/no. Recreio-Rio de Janeiro, CEP 22780-160 (Brazil)], E-mail: candida@ird.gov.br; Iwahara, A.; Poledna, R.; Silva, C.J. da; Delgado, J.U. [Laboratorio Nacional de Metrologia das Radiacoes Ionizantes /Instituto de Radioprotecao e Dosimetria (LNMRI/ IRD), Avenida Salvador Allende, s/no. Recreio-Rio de Janeiro, CEP 22780-160 (Brazil)

2007-09-21

This work describes the procedures for determining absolutely the {sup 51}Cr disintegration rate by using the 4{pi}{beta}-{gamma} coincidence and anti-coincidence counting and the sum-peak methods. A 4''x4''-NaI(Tl) scintillation detector was used in the {gamma}- channel of the 4{pi}{beta}-{gamma} coincidence system for {gamma}-ray counting. In the {beta}-channel, a 4{pi} gas flow proportional counter was used for counting of characteristic X-rays and Auger electrons originating from the electron capture events of the {sup 51}Cr decay scheme. Gamma spectrometry measurements by high-pure planar and coaxial germanium detectors were performed in the sum-peak method and in the determination of the 320 keV {gamma}-emission probability of {sup 51}Cr. This latter determined value agrees with the recent values found in the literature, confirming the reliability of the three methods used in this work for the disintegration rate measurements.

beta. and. gamma. -comparative dose estimates on Enewetak Atoll

Energy Technology Data Exchange (ETDEWEB)

Crase, K.W.; Gudiksen, P.H.; Robison, W.L. (California Univ., Livermore (USA). Lawrence Livermore National Lab.)

1982-05-01

Enewetak Atoll in the Pacific is used for atmospheric testing of U.S. nuclear weapons. Beta dose and ..gamma..-ray exposure measurements were made on two islands of the Enewetak Atoll during July-August 1976 to determine the ..beta.. and low energy ..gamma..-contribution to the total external radiation doses to the returning Marshallese. Measurements were made at numerous locations with thermoluminescent dosimeters (TLD), pressurized ionization chambers, portable NaI detectors, and thin-window pancake GM probes. Results of the TLD measurements with and without a ..beta..-attenuator indicate that approx. 29% of the total dose rate at 1 m in air is due to ..beta..- or low energy ..gamma..-contribution. The contribution at any particular site, however, is reduced by vegetation. Integral 30-yr external shallow dose estimates for future inhabitants were made and compared with external dose estimates of a previous large scale radiological survey. Integral 30-yr shallow external dose estimates are 25-50% higher than whole body estimates. Due to the low penetrating ability of the ..beta..'s or low energy ..gamma..'s, however, several remedial actions can be taken to reduce the shallow dose contribution to the total external dose.

Study of the Nuclear Structure of 39P Using Beta-Delayed Gamma Spectroscopy

Science.gov (United States)

Abromeit, Brittany; NSCL Experiment E14063 Team Team

2016-03-01

Investigation of nuclei with neutron and proton imbalance is at the forefront of nuclear physics research today. This is driven by the fact that the structure in these regimes may vary with that seen near the valley of stability. With eight neutrons more than the stable isotope of phosphorous, 39P is a neutron-rich exotic nucleus that has very limited information on it: previous studies of 39P produce only three known energy levels and gamma rays. The fragmentation of a 48Ca primary beam on a 564mg/cm2 thick Be target at the National Superconducting Cyclotron Laboratory (NSCL) was used to produce exotic 39Si. Using the NSCL Beta Counting System (BCS), consisting of a thick planner germanium double-sided strip detector (GeDSSD) and 16 High-purity germanium detectors in an array, SeGA, the beta-gamma coincidences from the decay of 39Si to 39P were analyzed. The resulting level scheme of 39P, including over 12 new gamma rays and energy states, confirmation of the previously measured half-life, and first-time logft values will be presented. This work was supported by the NSF under Grant No. 1401574.

The measurement of cross sections of inelastic and transfer reactions with gamma-particle coincidence

Energy Technology Data Exchange (ETDEWEB)

Zagatto, V.A.B.; Oliveira, J.R.B.; Pereira, D.; Allegro, P.R.P.; Chamon, L.C.; Cybulska, E.W.; Medina, N.H.; Ribas, R.V.; Rossi Junior, E.S.; Seale, W.A.; Silva, C.P.; Gasques, L. [Universidade de Sao Paulo (IF/USP), SP (Brazil). Inst. de Fisica; Toufen, D.L. [Instituto Federal de Educacao, Ciencia e Tecnologia, Guarulhos, SP (Brazil); Silveira, M.A.G. [Centro Universitario da FEI, Sao Bernardo do Campo, SP (Brazil); Zahn, G.S.; Genezini, F.A.; Shorto, J.M.B. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Lubian, J.; Linares, R. [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil). Inst. de Fisica; Nobre, G.P. [Lawrence Livermore National Laboratory, Livermore (United States)

2012-07-01

Full text: A new method was developed in Pelletron laboratory to measure gamma-particle coincidences and the chosen experiment to test this method was the {sup 18}O +{sup 110} Pd in the 46-60 MeV range. The following work aims to obtain experimental cross sections of inelastic excitation 0{sup +} {yields} 2{sup +} of {sup 110}Pd and transfer to excited states reactions (both measured by gamma-particle coincidences). The measurements were made at the Pelletron accelerator laboratory of the University of Sao Paulo with the Saci-Perere spectrometer [1], which consists of 4 GeHP Compton suppressed gamma detectors and a 4{pi} charged particle ancillary system with 11{Delta}E-E plastic phoswich scintillators (further details about the experimental procedure may be found in [2]). Calculations were performed with a new model based on the Sao Paulo Potential, specifically developed for the inclusion of dissipative processes like deep-inelastic collisions (DIC) [3,4] considering the Coulomb plus nuclear potential (with the aid of FRESCO code [5]). The experimental cross sections were obtained such as described in [6] including particle-gamma angular correlations, finite size of gamma and particle detectors as the vacuum de-alignment effects [7] (caused by hyperfine interaction) for the {sup 110}Pd inelastic reaction and for the {sup 110}Pd 2n transfer reaction. Also the effects of the beam spot size and energy loss in the target were included in these calculations. For these purposes a new code has been developed to assist in the data analysis. The gamma-particle angular correlations are calculated using the scattering amplitudes given by FRESCO. The theoretical predictions still consider 2 different types of normalization factors in its the real part: 1:0, and 0:6 as proposed in [3] for the weakly bound projectile cases. The analyses indicate that the 0:6 factor describes better the experimental data possible due to the large density of states in the transitional region. [1

Instrument limitation of accuracy of absolute measurement by method of 4π beta-gamma coincidence

International Nuclear Information System (INIS)

Plkh, J.

1979-01-01

Accuracy is discussed of determination of coincidence channels dead-time in 4π β-γ installation and determination of coincidence resolution time as well as conditions for determination and accuracy of these parameters. Conditions are considered under which these parameters have not been determined and there is wrong performance of the installation. Special attention was paid to the electronic circuit of the γ-channel. It has been shown that as a result of wrong performance of electronic circuit a new type of wrong coincidence appeared [ru

Design of an electronic system with simultaneous registering of pulse amplitude and event time applied to the 4πβ-γ coincidence method

International Nuclear Information System (INIS)

Toledo, Fabio de

2009-01-01

The 4πβ-γ coincidence method for absolute radionuclide activity measurement has been considered for many years as a primary standard in Nuclear Metrology, because of dependence on few observable quantities and high accuracy. The Laboratorio de Metrologia Nuclear (LMN) - Nuclear Metrology Laboratory -, at Instituto de Pesquisas Energeticas e Nucleares (IPEN) - Nuclear and Energy Research Institute -, among its measurement techniques, uses the 4πβ-γ coincidence method. Recently a new technique known as 'software coincidence' has been used, with many advantages over the conventional coincidence methodology. In order to update the methodologies for radionuclide standardizations, the LMN developed a new system based on the software coincidence technique, described in the present work. This system uses the same nuclear set up for beta and gamma detection. The new software coincidence electronics uses a National Instruments (NI) acquisition card connected to a microcomputer and, through a connection panel, to the nuclear detection set up. The card configuration and controlling is accomplished by software using the LabVIEW, a NI proprietary product. This system records into disk files all the amplitudes and occurrence times for beta and gamma detected pulses. A suitable software was developed (the coincidence analysis program) to process the recorded data in order to obtain beta, gamma and coincidence counts and perform calculation of the radioactive source activity. The work also presents and discusses the results obtained with the first version of the coincidence analysis program, as well as perspectives for future works. (author)

Absolute measurements of the alpha-gamma emitters activities by a sum-coincidence method

International Nuclear Information System (INIS)

Tobias, C.C.B.

1982-01-01

The absolute activity of U-235 contained in a UO 2 sample, using a sum-coincidence circuit which selected only the alpha particles which were simultaneous with the well known 184 Kev gamma radiation from Th-231. The alpha particles were detected by ZnS(Ag) scintillator specially designed to show its maximun efficiency for U-235 alpha particles, whereas the gamma radiation was detected by NaI(Tl) scintillation detector. The values obtained for the half-life of U-235 was compared with data from various observers using different experimental techniques. (Author) [pt

beta- and gamma-Comparative dose estimates on Eniwetok Atoll

Energy Technology Data Exchange (ETDEWEB)

Crase, K.W.; Gudiksen, P.H.; Robison, W.L.

1982-05-01

Eniwetok Atoll is one of the Pacific atolls used for atmospheric testing of U.S. nuclear weapons. Beta dose and gamma-ray exposure measurements were made on two islands of the Eniwetok Atoll during July-August 1976 to determine the beta and low energy gamma-contribution to the total external radiation doses to the returning Marshallese. Measurements were made at numerous locations with thermoluminescent dosimeters (TLD), pressurized ionization chambers, portable NaI detectors, and thin-window pancake GM probes. Results of the TLD measurements with and without a beta-attenuator indicate that approx. 29% of the total dose rate at 1 m in air is due to beta- or low energy gamma-contribution. The contribution at any particular site, however, is somewhat dependent on ground cover, since a minimal amount of vegetation will reduce it significantly from that over bare soil, but thick stands of vegetation have little effect on any further reductions. Integral 30-yr external shallow dose estimates for future inhabitants were made and compared with external dose estimates of a previous large scale radiological survey (En73). Integral 30-yr shallow external dose estimates are 25-50% higher than whole body estimates. Due to the low penetrating ability of the beta's or low energy gamma's, however, several remedial actions can be taken to reduce the shallow dose contribution to the total external dose.

Beta and Gamma Gradients

DEFF Research Database (Denmark)

Løvborg, Leif; Gaffney, C. F.; Clark, P. A.

1985-01-01

Experimental and/or theoretical estimates are presented concerning, (i) attenuation within the sample of beta and gamma radiation from the soil, (ii) the gamma dose within the sample due to its own radioactivity, and (iii) the soil gamma dose in the proximity of boundaries between regions...... of differing radioactivity. It is confirmed that removal of the outer 2 mm of sample is adequate to remove influence from soil beta dose and estimates are made of the error introduced by non-removal. Other evaluations include variation of the soil gamma dose near the ground surface and it appears...... that the present practice of avoiding samples above a depth of 0.3 m may be over-cautious...

Using CHIMERA detector at LNS for gamma-particle coincidences

Directory of Open Access Journals (Sweden)

Cardella G.

2016-01-01

Full Text Available We have recently evaluated the quality of γ-ray angular distributions that can be extracted in particle-gamma coincidence measurements using the CHIMERA detector at LNS. γ-rays have been detected using the CsI(Tl detectors of the spherical part of the CHIMERA array. Very clean γ-rays angular distributions were extracted in reactions induced by different stable beams impinging on 12C thin targets. The results evidenced an effect of projectile spin flip on the γ-rays angular distributions. γ-particle coincidence measurements were also performed in reactions induced by neutron rich exotic beams produced through in-flight fragmentation at LNS. In recent experiments also the Farcos array was used to improve energy and angular resolution measurements of the detected charged particles. Results obtained with both stable and radioactive beams are reported.

Coincidence summing corrections for positron emitters in germanium gamma spectrometry

International Nuclear Information System (INIS)

Richardson, A.E.; Sallee, W.W.; New Mexico State Univ., Las Cruces

1990-01-01

For positron emitters, 511 keV annihilation quanta are in coincidence with other gamma rays in the decay scheme. If the positrons are not localized at the point of decay, annihilation quanta will be produced at a site some distance from the point of emission. The magnitude of the summing coincidence effect will depend upon the position of annihilation. A method for determining the magnitude of the summing effect for a single gamma of energy E in coincidence with the annihilation gammas from non-localized positrons has been developed which makes use of the counting data for the full energy peaks for both the gamma ray (E) and the 511 keV annihilation gammas. With this data and efficiency calibration data one can determine the average total efficiency for the annihilation positions from which 511 keV gammas originate, and thereby obtain the summing correction factor, SCF, for gamma ray (E). Application of the method to a 22 Na NIST standard gave excellent agreement of observed emission rates for the 1275 keV gamma with the NIST value for wide ranging degrees of positron localization having summing correction factors ranging from 1.021 to 1.505. The method was also applied successfully to 58 Co in neutron-irradiated nickel foils. The method shows promise as a check on the accuracy of the efficiency calibration for a particular detector geometry at the 511 keV energy and energies for other gammas associated with positron emission. (orig.)

Theoretical study, and construction, of a spherical electrostatic beta spectrometer; Etude theorique et realisation d'un spectrometre beta electrostatique spherique

Energy Technology Data Exchange (ETDEWEB)

Moret, R [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

1964-03-15

After a literature survey showing the importance of an electrostatic spectrometer with spherical electrodes for studying disintegration processes, the theoretical characteristics of such an apparatus are derived (determination of the trajectory equations calculation of the transmission and of the resolving power the case of a point source and of an extended source). The apparatus built as a result of these calculations is described. The electrostatic field distribution outside the electrodes is derived. As well as giving electron spectra ({beta} disintegration and conversion electrons) the apparatus make s it possible to study e-{gamma}, e-{beta}, e-e-{gamma} and e-e-{beta} coincidences. In the last part are given experimental characteristics and the results of the first measurements made on conversion electron spectra ({sup 161}Tb, {sup 151}Pm, {sup 155}Eu) and on coincidences ({sup 170}Tm) using this spectrometer. (author) [French] Apres une etude bibliographique montrant l'interet que presente un spectrometre electrostatique a electrodes spheriques pour l'etude des schemas de desintegration, l'auteur etablit les caracteristiques theoriques d'un tel appareil (determination de l'equation des trajectoires calcul de la transmission et du pouvoir de resolution cas d'une source ponctuelle et d'une source etendue). On decrit l'appareil realise d'apres ces calculs. On etablit la repartition du champ electrostatique a l'exterieur des electrodes. Outre le trace des spectres d'electrons (desintegration {beta} et electrons de conversion), l'appareil permet l'etude de coincidences e-{gamma}, e-{beta}, e-e-{gamma} and e-e-{beta}. Dans la derniere partie, sont donnees les caracteristiques experimentales et les premieres etudes de spectres d'electrons de conversion ({sup 161}Tb, {sup 151}Pm, {sup 155}Eu) et de coincidences ({sup 170}Tm) faites a l'aide de ce spectrometre. (auteur)

Counting efficiency for radionuclides decaying by beta and gamma-ray emission; Calculo de la eficiencia de recuento de nucleidos que experimentan desintegracion beta y desexcitacion gamma simple

Energy Technology Data Exchange (ETDEWEB)

Grau, A.; Garcia-Torano, E.

1988-07-01

In this paper, counting efficiency vs figure of merit for beta and gamma-ray emitters has been computed. It is assumed that the decay scheme has only a gamma level and the beta-ray emission may be coincident with the gamma-rays or the internal-conversion electrons. The radionuclides tabulated are: 20 {sub 0}, 20{sub p}, 28{sub A}l, 35{sub p}, 41{sub A}r, 42{sub K}, 47{sub S}e, 62{sub F}e, 66{sub C}u, 81{sub G}e, 86{sub B}b, 108{sub R}u, 112{sub p}d, 121{sub S}n(Ni), 122{sub I}n, 129{sub I}, 141{sub C}e 171{sub T}m, 194{sub O}s, 2O3{sub H}g, 205{sub H}g, 210{sub p}b, 225{sub R}a, 142{sub p}r, 151{sub S}m, 244{sub A}m(m). It has been assumed that the liquid is a toluene based scintillator solution in standard glass vials containing 10 cm''3. (Author) 8 refs.

Elaboration of supports for beta emitting sources (with vyns); Elaboracion de soportes para fuentes emisoras beta (con vyns)

Energy Technology Data Exchange (ETDEWEB)

Cortes P, A.; Torre O, J. De la; Tejera R, A.; Becerril V, A.; Bribiesca S, L

1990-04-15

The Laboratory of Radioactive patterns account with a 4 {pi}{beta}-{gamma} coincidence system of recent acquisition with which absolute measures of radioactive activity with uncertainties of the order of 0.1% can be made. Since the coincidence method for the activity measure consists on detecting to the particle and the photon corresponding to oneself nuclear disintegration, it is necessary to elaborate special radioactive sources on thin supports, in order to allowing the maximum possible fluence of {beta} particles ({approx} 100%). This work a technique for the elaboration of these sources and for the measure of the thickness of the walls of the support is presented. (Author)

Standardisation of 64Cu using a software coincidence counting system

International Nuclear Information System (INIS)

Havelka, Miroslav; Sochorová, Jana

2014-01-01

The activity of the radionuclide 64 Cu was determined by the efficiency extrapolation method applied to 4π(PC)−γ coincidence counting. The standardisation was performed by software coincidence counting—a digital method for primary activity measurement that simplifies the setting of optimal coincidence parameters. The γ-ray-energy window, characterised by identical gamma detection efficiency related to the sum of EC and to the sum of beta decay branches, was found. This setting ensured a linear and zero slope extrapolation curve. - Highlights: • Standardisation realised by extrapolation method applied to 4π(PC)−γ coincidence. • Digital method for optimal setting of coincidence parameters was used. • Result with total standard uncertainty of 0.74% was obtained

Quantification of 235U and 238U activity concentrations for undeclared nuclear materials by a digital gamma-gamma coincidence spectroscopy.

Science.gov (United States)

Zhang, Weihua; Yi, Jing; Mekarski, Pawel; Ungar, Kurt; Hauck, Barry; Kramer, Gary H

2011-06-01

The purpose of this study is to investigate the possibility of verifying depleted uranium (DU), natural uranium (NU), low enriched uranium (LEU) and high enriched uranium (HEU) by a developed digital gamma-gamma coincidence spectroscopy. The spectroscopy consists of two NaI(Tl) scintillators and XIA LLC Digital Gamma Finder (DGF)/Pixie-4 software and card package. The results demonstrate that the spectroscopy provides an effective method of (235)U and (238)U quantification based on the count rate of their gamma-gamma coincidence counting signatures. The main advantages of this approach over the conventional gamma spectrometry include the facts of low background continuum near coincident signatures of (235)U and (238)U, less interference from other radionuclides by the gamma-gamma coincidence counting, and region-of-interest (ROI) imagine analysis for uranium enrichment determination. Compared to conventional gamma spectrometry, the method offers additional advantage of requiring minimal calibrations for (235)U and (238)U quantification at different sample geometries. Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.

Three-gamma annihilation of ortho-positronium in NiO/γ-Al2O3 catalysts detected by positron lifetime and coincidence Doppler broadening measurements

International Nuclear Information System (INIS)

Huang, S.H.; Chen, Z.Q.; Zhang, H.J.

2012-01-01

The pore structure of NiO/γ-Al 2 O 3 catalysts is characterized by positron lifetime and Doppler broadening measurements. A very long lifetime τ 4 of 92 ns is resolved from the positron lifetime spectrum measured for pure Al 2 O 3 , which could be attributed to the ortho-positronium (o-Ps) lifetime in large pores. It was also found that the fitted lifetime τ 4 and its corresponding intensity I 4 obtained from the lifetime spectra both decrease with narrowing energy window of the stop channel in the fast–fast coincidence lifetime measurement system. This suggests that the ultra long lifetime is primarily due to the self annihilation of o-Ps which emits three gamma-rays. Such 3γ annihilation is further evidenced by measuring the Doppler broadening of annihilation gamma rays in coincidence with the prompt gamma rays (1.28 MeV) emitted from the 22 Na positron source. In NiO/γ-Al 2 O 3 catalysts both the lifetime τ 4 and its intensity I 4 decreases with increasing NiO content (from 3 wt% to 40 wt%), which indicates decreasing of the number of 3γ events. The 3γ annihilation parameter analyzed from the coincidence Doppler broadening spectrum shows consistent decrease with increasing NiO content. - Highlights: ► Above paper reported study of the 3-gamma annihilation of o-Ps. ► 3γ annihilation was verified by varying the energy window of the lifetime system. ► A new coincidence Doppler broadening technique is also used to record 3γ events. ► 3γ parameter decreases with NiO content in NiO/γ-Al 2 O 3 catalysts.

Theoretical study and construction of a multichannel {beta} spectrometer with uniform magnetic field; Etude et realisation d'un spectrometre {beta} multivoies a champ magnetique uniforme

Energy Technology Data Exchange (ETDEWEB)

Schussler, F [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

1965-09-01

After a brief survey of the interest of a multichannel beta spectrometer for studying decay schemes of short lived nuclides (30 seconds minimum, the theoretically well known characteristics of uniform magnetic field analyser (image of a large source, transmission and resolution) are briefly remembered. In the second part, the apparatus built as a result of these calculations is described. This apparatus allows the determination of beta spectra by simultaneous determination of the beta spectra in coincidence with four gamma rays predetermined in the gamma spectrum of the studied nuclide. Finally, in the last part, the experimental characteristics of the spectrometer (calibration in energy and transmission) and the first measurement of beta spectra ({sup 155}Sm) and of coincidences ({sup 24}Na), are given. (author) [French] Apres avoir brievement souligne l'interet pratique que presente un spectrometre multivoies pour l'etude des schemas de desintegration des corps radioactifs de courtes periodes (30 secondes au maximum), l'auteur effectue un rappel des caracteristiques theoriques bien connues d'un analyseur magnetique a champ uniforme (image d'une source etendue) calcul de la transmission et du pouvoir de resolution. Une deuxieme partie est consacree a la description de l'appareil realise d'apres ces calculs. Cet appareil permet le releve des spectres beta par detection, simultanee de dix groupes d'electrons d'energies differentes; il permet egalement le releve simultane des spectres beta en coincidence avec quatre rayonnements gammas preselectionnes a l'avance dans le spectre gamma du corps etudie. Dans une derniere partie enfin, sont donnees les caracteristiques experimentales du spectrometre (etalonnage en energie et en transmission) ainsi que les premiers resultats des etudes de spectre beta ({sup 155}Sm) et de coincidence ({sup 24}Na). (auteur)

Selective Beta and Gamma-ray Discrimination by CdWO{sub 4} and PlasticScintillator

Energy Technology Data Exchange (ETDEWEB)

Bae, Jun Woo; Kim, Hee Reyoung [Dept. of Nuclear Engineering, Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of)

2017-04-15

Radiation monitoring technique has been used for monitoring of decommissioning site of nuclear facility, radioactive waste disposal site, or in case of radioactivity accident. For rapid measurement of gamma-ray and beta-ray, many portable radiation detectors were developed but they are sensitive to specific radiation type. For example, portable detectors using NaI(Tl) or high purity germanium (HPGe) are suitable to detect gamma-ray. Otherwise, Geiger-müller (GM) tube or ionization chamber are suitable to detect all-types of radiation but it is hard to determine which particle is detected in the detector. In this reason, phoswich detectors for discrimination of beta-ray and gamma-ray were developed by using pulse shape discrimination. In this study, another approach to discriminate the beta-ray and gamma-ray is carried out. Two scintillators are used, cadmium tungstate (CdWO{sub 4}) and plastic scintillator. They have huge difference in their effective atomic number and mass density, thus they have huge difference in their gamma-ray sensitivity while the sensitivity of beta-ray is similar. The characterization of beta-ray and gamma-ray discrimination by using this characteristics is include. A technique of discrimination between beta-ray and gamma-ray was suggested. The method was verified by Monte Carlo simulation and experiment. This work showed feasibility on in field measurement of radiation with discrimination of beta-ray and gamma-ray.

Absolute activity measurement and gamma-ray emission probability for decay of I-126; Medida absoluta da atividade e determinacao da taxa de emissao gama por decaimento do {sup 126} I

Energy Technology Data Exchange (ETDEWEB)

Fonseca, Katia Aparecida

1997-07-01

The accurate knowledge of the gamma-ray emission probability per decay of radionuclides is important in several applications. In the case of {sup 126} I, its importance lies mainly in fast neutron dosimetry as well as in the production of {sup 125} I where {sup 126} I appears as an impurity. In the present work the gamma-ray emission probabilities per decay for the 388 and 666-KeV transitions of {sup 126} I have been measured. This radionuclide was obtained by means of the {sup 127} I(n, 2n){sup 126} I reaction in a fast neutron flux at the IPEN 2 MW research reactor. The methodology for the primary standardization of {sup 126} I is described. For this purpose, two different coincidence systems were used due to the complex decay scheme of this radionuclide. The {beta}branch measurement was carried out in a 4 {pi}(PC){beta}-{gamma} coincidence system consisting of a proportional counter, coupled to a pair of 3'x3' Na I (Tl) crystal. The electron capture branch was measured in a X-{gamma} coincidence system using two NaI(Tl) crystals. The gamma-ray measurements were performed in a HPGe system, previously calibrated by means of standard sources supplied by the International Atomic Energy Agency. All the uncertainties evolved were treated rigorously, by means of covariance analysis. (author)

Absolute activity measurement and gamma-ray emission probability for decay of I-126; Medida absoluta da atividade e determinacao da taxa de emissao gama por decaimento do {sup 126} I

Energy Technology Data Exchange (ETDEWEB)

Fonseca, Katia Aparecida

1997-07-01

The accurate knowledge of the gamma-ray emission probability per decay of radionuclides is important in several applications. In the case of {sup 126} I, its importance lies mainly in fast neutron dosimetry as well as in the production of {sup 125} I where {sup 126} I appears as an impurity. In the present work the gamma-ray emission probabilities per decay for the 388 and 666-KeV transitions of {sup 126} I have been measured. This radionuclide was obtained by means of the {sup 127} I(n, 2n){sup 126} I reaction in a fast neutron flux at the IPEN 2 MW research reactor. The methodology for the primary standardization of {sup 126} I is described. For this purpose, two different coincidence systems were used due to the complex decay scheme of this radionuclide. The {beta}branch measurement was carried out in a 4 {pi}(PC){beta}-{gamma} coincidence system consisting of a proportional counter, coupled to a pair of 3'x3' Na I (Tl) crystal. The electron capture branch was measured in a X-{gamma} coincidence system using two NaI(Tl) crystals. The gamma-ray measurements were performed in a HPGe system, previously calibrated by means of standard sources supplied by the International Atomic Energy Agency. All the uncertainties evolved were treated rigorously, by means of covariance analysis. (author)

SU-G-IeP4-12: Performance of In-111 Coincident Gamma-Ray Counting: A Monte Carlo Simulation

Energy Technology Data Exchange (ETDEWEB)

Pahlka, R; Kappadath, S; Mawlawi, O [UT MD Anderson Cancer Center, Houston, TX (United States)

2016-06-15

Purpose: The decay of In-111 results in a non-isotropic gamma-ray cascade, which is normally imaged using a gamma camera. Creating images with a gamma camera using coincident gamma-rays from In-111 has not been previously studied. Our objective was to explore the feasibility of imaging this cascade as coincidence events and to determine the optimal timing resolution and source activity using Monte Carlo simulations. Methods: GEANT4 was used to simulate the decay of the In-111 nucleus and to model the gamma camera. Each photon emission was assigned a timestamp, and the time delay and angular separation for the second gamma-ray in the cascade was consistent with the known intermediate state half-life of 85ns. The gamma-rays are transported through a model of a Siemens dual head Symbia “S” gamma camera with a 5/8-inch thick crystal and medium energy collimators. A true coincident event was defined as a single 171keV gamma-ray followed by a single 245keV gamma-ray within a specified time window (or vice versa). Several source activities (ranging from 10uCi to 5mCi) with and without incorporation of background counts were then simulated. Each simulation was analyzed using varying time windows to assess random events. The noise equivalent count rate (NECR) was computed based on the number of true and random counts for each combination of activity and time window. No scatter events were assumed since sources were simulated in air. Results: As expected, increasing the timing window increased the total number of observed coincidences albeit at the expense of true coincidences. A timing window range of 200–500ns maximizes the NECR at clinically-used source activities. The background rate did not significantly alter the maximum NECR. Conclusion: This work suggests coincident measurements of In-111 gamma-ray decay can be performed with commercial gamma cameras at clinically-relevant activities. Work is ongoing to assess useful clinical applications.

Annihilation gamma ray background characterization and rejection for a positron camera

International Nuclear Information System (INIS)

Levin, C.S.; Tornai, M.P.; MacDonald, L.R.

1996-01-01

We have developed a miniature (1.2 cm 2 ) beta-ray camera prototype to assist a surgeon in locating and removing the margins of a resected tumor. When imaging positron emitting radiopharmaceuticals, annihilation gamma ray interactions in the detector can mimic those of the betas. The extent of the background contamination depends on the detector, geometry and tumor specificity of the radiopharmaceutical. We have characterized the effects that annihilation gamma rays have on positron imaging with the camera. We studied beta and gamma ray detection rates and imaging using small positron or electron sources directly exposed to the detector to simulate hot tumor remnants and a cylinder filled with 18 F to simulate annihilation background from the brain. For various ratios of phantom brain/tumor activity, a annihilation gamma rate of 1.8 cts/sec/gCi was measured in the CaF 2 (Eu) detector. We present two gamma-ray background rejection schemes that use a β-γ coincidence. Results show that the coincidence methods works with ∼99% gamma ray rejection efficiency

Beta and gamma decay heat measurements between 0.1s--50,000s for neutron fission of 235U, 238U and 239Pu

International Nuclear Information System (INIS)

Schier, W.A.; Couchell, G.P.

1993-01-01

A helium-jet/tape-transport system is employed in the study of beta-particle and gamma-ray energy spectra of aggregate fission products as a function of time after fission. During the initial nine months of this project we have investigated the following areas: Design, assembly and characterization of a beta-particle spectrometer; Measurement of 235 U(n th ff) beta spectra for delay times 0.2 s to 12,000 s; Assembly and characterization of a 5 x 5 Nal(Tl) gamma-ray spectrometer; Measurement of 235 U(n th ff) gamma-ray spectra for delay times 0.2s to 1 5,500s; Assembly and characterization of HPGe gamma-ray spectrometer with a Nal(Tl) Compton-and-background-suppression annulus; Measurement of 235 U(n th ,ff) high-resolution gamma-ray spectra for delay times 0.6 s to over 100,000 s; Comparison of individual gamma-line intensities with ENDF/B-VI; Adaptation to our computer of unfolding program FERDO for beta and gamma aggregate fission-product energy spectra and development of a spectrum-stripping program for analysis of HPGe gamma-ray spectra; Study of the helium-jet fission-fragment elemental transfer efficiency. This work has resulted in the publication of twelve BAPS abstracts of presentations at scientific meetings. There are currently four Ph.D. and two M.S. candidates working on dissertations associated with the project

Spectral shapes and a beta-gamma directional correlation in the beta decay of 172Tm (Jpi = 2-)

DEFF Research Database (Denmark)

Gregers Hansen, P.; Loft Nielsen, H.; Wilsky, K.

1966-01-01

The isotope 172Tm populates the 0+, 2+ and 4+ states of the 172Yb ground-state rotational band directly in beta decay. The shapes and intensities of the three beta groups have been measured by means of a six-gap magnetic spectrometer operated in coincidence with a Nal(Tl) crystal. The experimenta...

Top-Down Beta Enhances Bottom-Up Gamma.

Science.gov (United States)

Richter, Craig G; Thompson, William H; Bosman, Conrado A; Fries, Pascal

2017-07-12

Several recent studies have demonstrated that the bottom-up signaling of a visual stimulus is subserved by interareal gamma-band synchronization, whereas top-down influences are mediated by alpha-beta band synchronization. These processes may implement top-down control of stimulus processing if top-down and bottom-up mediating rhythms are coupled via cross-frequency interaction. To test this possibility, we investigated Granger-causal influences among awake macaque primary visual area V1, higher visual area V4, and parietal control area 7a during attentional task performance. Top-down 7a-to-V1 beta-band influences enhanced visually driven V1-to-V4 gamma-band influences. This enhancement was spatially specific and largest when beta-band activity preceded gamma-band activity by ∼0.1 s, suggesting a causal effect of top-down processes on bottom-up processes. We propose that this cross-frequency interaction mechanistically subserves the attentional control of stimulus selection. SIGNIFICANCE STATEMENT Contemporary research indicates that the alpha-beta frequency band underlies top-down control, whereas the gamma-band mediates bottom-up stimulus processing. This arrangement inspires an attractive hypothesis, which posits that top-down beta-band influences directly modulate bottom-up gamma band influences via cross-frequency interaction. We evaluate this hypothesis determining that beta-band top-down influences from parietal area 7a to visual area V1 are correlated with bottom-up gamma frequency influences from V1 to area V4, in a spatially specific manner, and that this correlation is maximal when top-down activity precedes bottom-up activity. These results show that for top-down processes such as spatial attention, elevated top-down beta-band influences directly enhance feedforward stimulus-induced gamma-band processing, leading to enhancement of the selected stimulus. Copyright © 2017 Richter, Thompson et al.

Elaboration of Co-60 sources on gilding vyns, with beta efficiencies 80 % or better and its activity measure by the coincidences method

International Nuclear Information System (INIS)

Cortes P, A.; Tejera R, A.; Becerril V, A.; Ortiz C, A.

1991-12-01

The measuring technique of radioactive activity by the coincidences method 4 π β - γ it requires of the elaboration of radioactive sources on thin supports in order to flows the biggest percentage of beta particles, those of the order of the 80 % or but. In this work a procedure for the elaboration of this type of sources, with gilding Vyns is reported. (Author)

Using support vector machine to predict beta- and gamma-turns in proteins.

Science.gov (United States)

Hu, Xiuzhen; Li, Qianzhong

2008-09-01

By using the composite vector with increment of diversity, position conservation scoring function, and predictive secondary structures to express the information of sequence, a support vector machine (SVM) algorithm for predicting beta- and gamma-turns in the proteins is proposed. The 426 and 320 nonhomologous protein chains described by Guruprasad and Rajkumar (Guruprasad and Rajkumar J. Biosci 2000, 25,143) are used for training and testing the predictive model of the beta- and gamma-turns, respectively. The overall prediction accuracy and the Matthews correlation coefficient in 7-fold cross-validation are 79.8% and 0.47, respectively, for the beta-turns. The overall prediction accuracy in 5-fold cross-validation is 61.0% for the gamma-turns. These results are significantly higher than the other algorithms in the prediction of beta- and gamma-turns using the same datasets. In addition, the 547 and 823 nonhomologous protein chains described by Fuchs and Alix (Fuchs and Alix Proteins: Struct Funct Bioinform 2005, 59, 828) are used for training and testing the predictive model of the beta- and gamma-turns, and better results are obtained. This algorithm may be helpful to improve the performance of protein turns' prediction. To ensure the ability of the SVM method to correctly classify beta-turn and non-beta-turn (gamma-turn and non-gamma-turn), the receiver operating characteristic threshold independent measure curves are provided. (c) 2008 Wiley Periodicals, Inc.

Determination of $\\gamma$ and $-2\\beta_s$ from charmless two-body decays of beauty mesons

CERN Document Server

Aaij, Roel; Adeva, Bernardo; Adinolfi, Marco; Affolder, Anthony; Ajaltouni, Ziad; Akar, Simon; Albrecht, Johannes; Alessio, Federico; Alexander, Michael; Ali, Suvayu; Alkhazov, Georgy; Alvarez Cartelle, Paula; Alves Jr, Antonio Augusto; Amato, Sandra; Amerio, Silvia; Amhis, Yasmine; An, Liupan; Anderlini, Lucio; Anderson, Jonathan; Andreassen, Rolf; Andreotti, Mirco; Andrews, Jason; Appleby, Robert; Aquines Gutierrez, Osvaldo; Archilli, Flavio; Artamonov, Alexander; Artuso, Marina; Aslanides, Elie; Auriemma, Giulio; Baalouch, Marouen; Bachmann, Sebastian; Back, John; Badalov, Alexey; Baesso, Clarissa; Baldini, Wander; Barlow, Roger; Barschel, Colin; Barsuk, Sergey; Barter, William; Batozskaya, Varvara; Battista, Vincenzo; Bay, Aurelio; Beaucourt, Leo; Beddow, John; Bedeschi, Franco; Bediaga, Ignacio; Belogurov, Sergey; Belous, Konstantin; Belyaev, Ivan; Ben-Haim, Eli; Bencivenni, Giovanni; Benson, Sean; Benton, Jack; Berezhnoy, Alexander; Bernet, Roland; Bettler, Marc-Olivier; van Beuzekom, Martinus; Bien, Alexander; Bifani, Simone; Bird, Thomas; Bizzeti, Andrea; Bjørnstad, Pål Marius; Blake, Thomas; Blanc, Frédéric; Blouw, Johan; Blusk, Steven; Bocci, Valerio; Bondar, Alexander; Bondar, Nikolay; Bonivento, Walter; Borghi, Silvia; Borgia, Alessandra; Borsato, Martino; Bowcock, Themistocles; Bowen, Espen Eie; Bozzi, Concezio; Brambach, Tobias; Bressieux, Joël; Brett, David; Britsch, Markward; Britton, Thomas; Brodzicka, Jolanta; Brook, Nicholas; Brown, Henry; Bursche, Albert; Busetto, Giovanni; Buytaert, Jan; Cadeddu, Sandro; Calabrese, Roberto; Calvi, Marta; Calvo Gomez, Miriam; Campana, Pierluigi; Campora Perez, Daniel; Carbone, Angelo; Carboni, Giovanni; Cardinale, Roberta; Cardini, Alessandro; Carson, Laurence; Carvalho Akiba, Kazuyoshi; Casse, Gianluigi; Cassina, Lorenzo; Castillo Garcia, Lucia; Cattaneo, Marco; Cauet, Christophe; Cenci, Riccardo; Charles, Matthew; Charpentier, Philippe; Chefdeville, Maximilien; Chen, Shanzhen; Cheung, Shu-Faye; Chiapolini, Nicola; Chrzaszcz, Marcin; 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Dzhelyadin, Rustem; Dziurda, Agnieszka; Dzyuba, Alexey; Easo, Sajan; Egorychev, Victor; Eidelman, Semen; Eisenhardt, Stephan; Eitschberger, Ulrich; Ekelhof, Robert; Eklund, Lars; El Rifai, Ibrahim; Elsasser, Christian; Ely, Scott; Esen, Sevda; Evans, Hannah Mary; Evans, Timothy; Falabella, Antonio; Färber, Christian; Farinelli, Chiara; Farley, Nathanael; Farry, Stephen; Fay, Robert; Ferguson, Dianne; Fernandez Albor, Victor; Ferreira Rodrigues, Fernando; Ferro-Luzzi, Massimiliano; Filippov, Sergey; Fiore, Marco; Fiorini, Massimiliano; Firlej, Miroslaw; Fitzpatrick, Conor; Fiutowski, Tomasz; Fol, Philip; Fontana, Marianna; Fontanelli, Flavio; Forty, Roger; Francisco, Oscar; Frank, Markus; Frei, Christoph; Frosini, Maddalena; Fu, Jinlin; Furfaro, Emiliano; Gallas Torreira, Abraham; Galli, Domenico; Gallorini, Stefano; Gambetta, Silvia; Gandelman, Miriam; Gandini, Paolo; Gao, Yuanning; García Pardiñas, Julián; Garofoli, Justin; Garra Tico, Jordi; Garrido, Lluis; Gaspar, Clara; Gauld, Rhorry; 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Rachwal, Bartolomiej; Rademacker, Jonas; Rakotomiaramanana, Barinjaka; Rama, Matteo; Rangel, Murilo; Raniuk, Iurii; Rauschmayr, Nathalie; Raven, Gerhard; Redi, Federico; Reichert, Stefanie; Reid, Matthew; dos Reis, Alberto; Ricciardi, Stefania; Richards, Sophie; Rihl, Mariana; Rinnert, Kurt; Rives Molina, Vincente; Robbe, Patrick; Rodrigues, Ana Barbara; Rodrigues, Eduardo; Rodriguez Perez, Pablo; Roiser, Stefan; Romanovsky, Vladimir; Romero Vidal, Antonio; Rotondo, Marcello; Rouvinet, Julien; Ruf, Thomas; Ruiz, Hugo; Ruiz Valls, Pablo; Saborido Silva, Juan Jose; Sagidova, Naylya; Sail, Paul; Saitta, Biagio; Salustino Guimaraes, Valdir; Sanchez Mayordomo, Carlos; Sanmartin Sedes, Brais; Santacesaria, Roberta; Santamarina Rios, Cibran; Santovetti, Emanuele; Sarti, Alessio; Satriano, Celestina; Satta, Alessia; Saunders, Daniel Martin; Savrie, Mauro; Savrina, Darya; Schiller, Manuel; Schindler, Heinrich; Schlupp, Maximilian; Schmelling, Michael; Schmidt, Burkhard; Schneider, Olivier; Schopper, Andreas; Schune, Marie Helene; Schwemmer, Rainer; Sciascia, Barbara; Sciubba, Adalberto; Seco, Marcos; Semennikov, Alexander; Sepp, Indrek; Serra, Nicola; Serrano, Justine; Sestini, Lorenzo; Seyfert, Paul; Shapkin, Mikhail; Shapoval, Illya; Shcheglov, Yury; Shears, Tara; Shekhtman, Lev; Shevchenko, Vladimir; Shires, Alexander; Silva Coutinho, Rafael; Simi, Gabriele; Sirendi, Marek; Skidmore, Nicola; Skwarnicki, Tomasz; Smith, Anthony; Smith, Edmund; Smith, Eluned; Smith, Jackson; Smith, Mark; Snoek, Hella; Sokoloff, Michael; Soler, Paul; Soomro, Fatima; Souza, Daniel; Souza De Paula, Bruno; Spaan, Bernhard; Sparkes, Ailsa; Spradlin, Patrick; Sridharan, Srikanth; Stagni, Federico; Stahl, Marian; Stahl, Sascha; Steinkamp, Olaf; Stenyakin, Oleg; Stevenson, Scott; Stoica, Sabin; Stone, Sheldon; Storaci, Barbara; Stracka, Simone; Straticiuc, Mihai; Straumann, Ulrich; Stroili, Roberto; Subbiah, Vijay Kartik; Sun, Liang; Sutcliffe, William; Swientek, Krzysztof; Swientek, Stefan; Syropoulos, Vasileios; Szczekowski, Marek; Szczypka, Paul; Szilard, Daniela; Szumlak, Tomasz; T'Jampens, Stephane; Teklishyn, Maksym; Tellarini, Giulia; Teubert, Frederic; Thomas, Christopher; Thomas, Eric; van Tilburg, Jeroen; Tisserand, Vincent; Tobin, Mark; Tolk, Siim; Tomassetti, Luca; Topp-Joergensen, Stig; Torr, Nicholas; Tournefier, Edwige; Tourneur, Stephane; Tran, Minh Tâm; Tresch, Marco; Tsaregorodtsev, Andrei; Tsopelas, Panagiotis; Tuning, Niels; Ubeda Garcia, Mario; Ukleja, Artur; Ustyuzhanin, Andrey; Uwer, Ulrich; Vacca, Claudia; Vagnoni, Vincenzo; Valenti, Giovanni; Vallier, Alexis; Vazquez Gomez, Ricardo; Vazquez Regueiro, Pablo; Vázquez Sierra, Carlos; Vecchi, Stefania; Velthuis, Jaap; Veltri, Michele; Veneziano, Giovanni; Vesterinen, Mika; Viaud, Benoit; Vieira, Daniel; Vieites Diaz, Maria; Vilasis-Cardona, Xavier; Vollhardt, Achim; Volyanskyy, Dmytro; Voong, David; Vorobyev, Alexey; Vorobyev, Vitaly; Voß, Christian; Voss, Helge; de Vries, Jacco; Waldi, Roland; Wallace, Charlotte; Wallace, Ronan; Walsh, John; Wandernoth, Sebastian; Wang, Jianchun; Ward, David; Watson, Nigel; Websdale, David; Whitehead, Mark; Wicht, Jean; Wiedner, Dirk; Wilkinson, Guy; Williams, Matthew; Williams, Mike; Wilschut, Hans; Wilson, Fergus; Wimberley, Jack; Wishahi, Julian; Wislicki, Wojciech; Witek, Mariusz; Wormser, Guy; Wotton, Stephen; Wright, Simon; Wyllie, Kenneth; Xie, Yuehong; Xing, Zhou; Xu, Zhirui; Yang, Zhenwei; Yuan, Xuhao; Yushchenko, Oleg; Zangoli, Maria; Zavertyaev, Mikhail; Zhang, Liming; Zhang, Wen Chao; Zhang, Yanxi; Zhelezov, Alexey; Zhokhov, Anatoly; Zhong, Liang; Zvyagin, Alexander

2015-01-01

Using the latest LHCb measurements of time-dependent $C\\!P$ violation in the $B^0_s \\to K^+K^-$ decay, a U-spin relation between the decay amplitudes of $B^0_s \\to K^+K^-$ and $B^0\\to \\pi^+\\pi^-$ decay processes allows constraints to be placed on the angle $\\gamma$ of the unitarity triangle and on the $B^0_s$ mixing phase $-2\\beta_s$. Results from an extended approach, which uses additional inputs on $B^0\\to \\pi^0\\pi^0$ and $B^+\\to \\pi^+\\pi^0$ decays from other experiments and exploits isospin symmetry, are also presented. The dependence of the results on the maximum allowed amount of U-spin breaking is studied. At 68% probability, the value $\\gamma = \\left( 63.5^{\\,+\\, 7.2}_{\\,-\\,6.7} \\right)^\\circ~\\mathrm{modulo}~180^\\circ$ is determined. In an alternative analysis, the value $-2\\beta_s = -0.12 ^{\\,+\\,0.14}_{\\,-\\,0.16}\\,\\,\\mathrm{rad}$ is found. In both measurements, the uncertainties due to U-spin breaking effects up to 50% are included.

Determination of $\\gamma$ and $-2\\beta_s$ from charmless two-body decays of beauty mesons

CERN Document Server

Aaij, Roel; Adeva, Bernardo; Adinolfi, Marco; Affolder, Anthony; Ajaltouni, Ziad; Akar, Simon; Albrecht, Johannes; Alessio, Federico; Alexander, Michael; Ali, Suvayu; Alkhazov, Georgy; Alvarez Cartelle, Paula; Alves Jr, Antonio Augusto; Amato, Sandra; Amerio, Silvia; Amhis, Yasmine; An, Liupan; Anderlini, Lucio; Anderson, Jonathan; Andreassen, Rolf; Andreotti, Mirco; Andrews, Jason; Appleby, Robert; Aquines Gutierrez, Osvaldo; Archilli, Flavio; Artamonov, Alexander; Artuso, Marina; Aslanides, Elie; Auriemma, Giulio; Baalouch, Marouen; Bachmann, Sebastian; Back, John; Badalov, Alexey; Baesso, Clarissa; Baldini, Wander; Barlow, Roger; Barschel, Colin; Barsuk, Sergey; Barter, William; Batozskaya, Varvara; Battista, Vincenzo; Bay, Aurelio; Beaucourt, Leo; Beddow, John; Bedeschi, Franco; Bediaga, Ignacio; Belogurov, Sergey; Belous, Konstantin; Belyaev, Ivan; Ben-Haim, Eli; Bencivenni, Giovanni; Benson, Sean; Benton, Jack; Berezhnoy, Alexander; Bernet, Roland; Bettler, Marc-Olivier; van Beuzekom, Martinus; Bien, Alexander; Bifani, Simone; Bird, Thomas; Bizzeti, Andrea; Bjørnstad, Pål Marius; Blake, Thomas; Blanc, Frédéric; Blouw, Johan; Blusk, Steven; Bocci, Valerio; Bondar, Alexander; Bondar, Nikolay; Bonivento, Walter; Borghi, Silvia; Borgia, Alessandra; Borsato, Martino; Bowcock, Themistocles; Bowen, Espen Eie; Bozzi, Concezio; Brambach, Tobias; Bressieux, Joël; Brett, David; Britsch, Markward; Britton, Thomas; Brodzicka, Jolanta; Brook, Nicholas; Brown, Henry; Bursche, Albert; Busetto, Giovanni; Buytaert, Jan; Cadeddu, Sandro; Calabrese, Roberto; Calvi, Marta; Calvo Gomez, Miriam; Campana, Pierluigi; Campora Perez, Daniel; Carbone, Angelo; Carboni, Giovanni; Cardinale, Roberta; Cardini, Alessandro; Carson, Laurence; Carvalho Akiba, Kazuyoshi; Casse, Gianluigi; Cassina, Lorenzo; Castillo Garcia, Lucia; Cattaneo, Marco; Cauet, Christophe; Cenci, Riccardo; Charles, Matthew; Charpentier, Philippe; Chefdeville, Maximilien; Chen, Shanzhen; Cheung, Shu-Faye; Chiapolini, Nicola; Chrzaszcz, Marcin; Ciba, Krzystof; Cid Vidal, Xabier; Ciezarek, Gregory; Clarke, Peter; Clemencic, Marco; Cliff, Harry; Closier, Joel; Coco, Victor; Cogan, Julien; Cogneras, Eric; Cojocariu, Lucian; Collins, Paula; Comerma-Montells, Albert; Contu, Andrea; Cook, Andrew; Coombes, Matthew; Coquereau, Samuel; Corti, Gloria; Corvo, Marco; Counts, Ian; Couturier, Benjamin; Cowan, Greig; Craik, Daniel Charles; Cruz Torres, Melissa Maria; Cunliffe, Samuel; Currie, Robert; D'Ambrosio, Carmelo; Dalseno, Jeremy; David, Pascal; David, Pieter; Davis, Adam; De Bruyn, Kristof; De Capua, Stefano; De Cian, Michel; De Miranda, Jussara; De Paula, Leandro; De Silva, Weeraddana; De Simone, Patrizia; Decamp, Daniel; Deckenhoff, Mirko; Del Buono, Luigi; Déléage, Nicolas; Derkach, Denis; Deschamps, Olivier; Dettori, Francesco; Di Canto, Angelo; Dijkstra, Hans; Donleavy, Stephanie; Dordei, Francesca; Dorigo, Mirco; Dosil Suárez, Alvaro; Dossett, David; Dovbnya, Anatoliy; Dreimanis, Karlis; Dujany, Giulio; Dupertuis, Frederic; Durante, Paolo; Dzhelyadin, Rustem; Dziurda, Agnieszka; Dzyuba, Alexey; Easo, Sajan; Egorychev, Victor; Eidelman, Semen; Eisenhardt, Stephan; Eitschberger, Ulrich; Ekelhof, Robert; Eklund, Lars; El Rifai, Ibrahim; Elsasser, Christian; Ely, Scott; Esen, Sevda; Evans, Hannah Mary; Evans, Timothy; Falabella, Antonio; Färber, Christian; Farinelli, Chiara; Farley, Nathanael; Farry, Stephen; Fay, Robert; Ferguson, Dianne; Fernandez Albor, Victor; Ferreira Rodrigues, Fernando; Ferro-Luzzi, Massimiliano; Filippov, Sergey; Fiore, Marco; Fiorini, Massimiliano; Firlej, Miroslaw; Fitzpatrick, Conor; Fiutowski, Tomasz; Fol, Philip; Fontana, Marianna; Fontanelli, Flavio; Forty, Roger; Francisco, Oscar; Frank, Markus; Frei, Christoph; Frosini, Maddalena; Fu, Jinlin; Furfaro, Emiliano; Gallas Torreira, Abraham; Galli, Domenico; Gallorini, Stefano; Gambetta, Silvia; Gandelman, Miriam; Gandini, Paolo; Gao, Yuanning; García Pardiñas, Julián; Garofoli, Justin; Garra Tico, Jordi; Garrido, Lluis; Gaspar, Clara; Gauld, Rhorry; Gavardi, Laura; Gavrilov, Gennadii; Geraci, Angelo; Gersabeck, Evelina; Gersabeck, Marco; Gershon, Timothy; Ghez, Philippe; Gianelle, Alessio; Gianì, Sebastiana; Gibson, Valerie; Giubega, Lavinia-Helena; Gligorov, V.V.; Göbel, Carla; Golubkov, Dmitry; Golutvin, Andrey; Gomes, Alvaro; Gotti, Claudio; Grabalosa Gándara, Marc; Graciani Diaz, Ricardo; Granado Cardoso, Luis Alberto; Graugés, Eugeni; Graziani, Giacomo; Grecu, Alexandru; Greening, Edward; Gregson, Sam; Griffith, Peter; Grillo, Lucia; Grünberg, Oliver; Gui, Bin; Gushchin, Evgeny; Guz, Yury; Gys, Thierry; Hadjivasiliou, Christos; Haefeli, Guido; Haen, Christophe; Haines, Susan; Hall, Samuel; Hamilton, Brian; Hampson, Thomas; Han, Xiaoxue; Hansmann-Menzemer, Stephanie; Harnew, Neville; Harnew, Samuel; Harrison, Jonathan; He, Jibo; Head, Timothy; Heijne, Veerle; Hennessy, Karol; Henrard, Pierre; Henry, Louis; Hernando Morata, Jose Angel; van Herwijnen, Eric; Heß, Miriam; Hicheur, Adlène; Hill, Donal; Hoballah, Mostafa; Hombach, Christoph; Hulsbergen, Wouter; Hunt, Philip; Hussain, Nazim; Hutchcroft, David; Hynds, Daniel; Idzik, Marek; Ilten, Philip; Jacobsson, Richard; Jaeger, Andreas; Jalocha, Pawel; Jans, Eddy; Jaton, Pierre; Jawahery, Abolhassan; Jing, Fanfan; John, Malcolm; Johnson, Daniel; Jones, Christopher; Joram, Christian; Jost, Beat; Jurik, Nathan; Kaballo, Michael; Kandybei, Sergii; Kanso, Walaa; Karacson, Matthias; Karbach, Moritz; Karodia, Sarah; Kelsey, Matthew; Kenyon, Ian; Ketel, Tjeerd; Khanji, Basem; Khurewathanakul, Chitsanu; Klaver, Suzanne; Klimaszewski, Konrad; Kochebina, Olga; Kolpin, Michael; Komarov, Ilya; Koopman, Rose; Koppenburg, Patrick; Korolev, Mikhail; Kozlinskiy, Alexandr; Kravchuk, Leonid; Kreplin, Katharina; Kreps, Michal; Krocker, Georg; Krokovny, Pavel; Kruse, Florian; Kucewicz, Wojciech; Kucharczyk, Marcin; Kudryavtsev, Vasily; Kurek, Krzysztof; Kvaratskheliya, Tengiz; La Thi, Viet Nga; Lacarrere, Daniel; Lafferty, George; Lai, Adriano; Lambert, Dean; Lambert, Robert W; Lanfranchi, Gaia; Langenbruch, Christoph; Langhans, Benedikt; Latham, Thomas; Lazzeroni, Cristina; Le Gac, Renaud; van Leerdam, Jeroen; Lees, Jean-Pierre; Lefèvre, Regis; Leflat, Alexander; Lefrançois, Jacques; Leo, Sabato; Leroy, Olivier; Lesiak, Tadeusz; Leverington, Blake; Li, Yiming; Likhomanenko, Tatiana; Liles, Myfanwy; Lindner, Rolf; Linn, Christian; Lionetto, Federica; Liu, Bo; Lohn, Stefan; Longstaff, Iain; Lopes, Jose; Lopez-March, Neus; Lowdon, Peter; Lu, Haiting; Lucchesi, Donatella; Luo, Haofei; Lupato, Anna; Luppi, Eleonora; Lupton, Oliver; Machefert, Frederic; Machikhiliyan, Irina V; Maciuc, Florin; Maev, Oleg; Malde, Sneha; Malinin, Alexander; Manca, Giulia; Mancinelli, Giampiero; Mapelli, Alessandro; Maratas, Jan; Marchand, Jean François; Marconi, Umberto; Marin Benito, Carla; Marino, Pietro; Märki, Raphael; Marks, Jörg; Martellotti, Giuseppe; Martens, Aurelien; Martín Sánchez, Alexandra; Martinelli, Maurizio; Martinez Santos, Diego; Martinez Vidal, Fernando; Martins Tostes, Danielle; Massafferri, André; Matev, Rosen; Mathe, Zoltan; Matteuzzi, Clara; Mazurov, Alexander; McCann, Michael; McCarthy, James; McNab, Andrew; McNulty, Ronan; McSkelly, Ben; Meadows, Brian; Meier, Frank; Meissner, Marco; Merk, Marcel; Milanes, Diego Alejandro; Minard, Marie-Noelle; Moggi, Niccolò; Molina Rodriguez, Josue; Monteil, Stephane; Morandin, Mauro; Morawski, Piotr; Mordà, Alessandro; Morello, Michael Joseph; Moron, Jakub; Morris, Adam Benjamin; Mountain, Raymond; Muheim, Franz; Müller, Katharina; Mussini, Manuel; Muster, Bastien; Naik, Paras; Nakada, Tatsuya; Nandakumar, Raja; Nasteva, Irina; Needham, Matthew; Neri, Nicola; Neubert, Sebastian; Neufeld, Niko; Neuner, Max; Nguyen, Anh Duc; Nguyen, Thi-Dung; Nguyen-Mau, Chung; Nicol, Michelle; Niess, Valentin; Niet, Ramon; Nikitin, Nikolay; Nikodem, Thomas; Novoselov, Alexey; O'Hanlon, Daniel Patrick; Oblakowska-Mucha, Agnieszka; Obraztsov, Vladimir; Oggero, Serena; Ogilvy, Stephen; Okhrimenko, Oleksandr; Oldeman, Rudolf; Onderwater, Gerco; Orlandea, Marius; Otalora Goicochea, Juan Martin; Owen, Patrick; Oyanguren, Maria Arantza; Pal, Bilas Kanti; Palano, Antimo; Palombo, Fernando; Palutan, Matteo; Panman, Jacob; Papanestis, Antonios; Pappagallo, Marco; Pappalardo, Luciano; Parkes, Christopher; Parkinson, Christopher John; Passaleva, Giovanni; Patel, Girish; Patel, Mitesh; Patrignani, Claudia; Pazos Alvarez, Antonio; Pearce, Alex; Pellegrino, Antonio; Pepe Altarelli, Monica; Perazzini, Stefano; Perez Trigo, Eliseo; Perret, Pascal; Perrin-Terrin, Mathieu; Pescatore, Luca; Pesen, Erhan; Petridis, Konstantin; Petrolini, Alessandro; Picatoste Olloqui, Eduardo; Pietrzyk, Boleslaw; Pilař, Tomas; Pinci, Davide; Pistone, Alessandro; Playfer, Stephen; Plo Casasus, Maximo; Polci, Francesco; Poluektov, Anton; Polycarpo, Erica; Popov, Alexander; Popov, Dmitry; Popovici, Bogdan; Potterat, Cédric; Price, Eugenia; Price, Joseph David; Prisciandaro, Jessica; Pritchard, Adrian; Prouve, Claire; Pugatch, Valery; Puig Navarro, Albert; Punzi, Giovanni; Qian, Wenbin; Rachwal, Bartolomiej; Rademacker, Jonas; Rakotomiaramanana, Barinjaka; Rama, Matteo; Rangel, Murilo; Raniuk, Iurii; Rauschmayr, Nathalie; Raven, Gerhard; Redi, Federico; Reichert, Stefanie; Reid, Matthew; dos Reis, Alberto; Ricciardi, Stefania; Richards, Sophie; Rihl, Mariana; Rinnert, Kurt; Rives Molina, Vincente; Robbe, Patrick; Rodrigues, Ana Barbara; Rodrigues, Eduardo; Rodriguez Perez, Pablo; Roiser, Stefan; Romanovsky, Vladimir; Romero Vidal, Antonio; Rotondo, Marcello; Rouvinet, Julien; Ruf, Thomas; Ruiz, Hugo; Ruiz Valls, Pablo; Saborido Silva, Juan Jose; Sagidova, Naylya; Sail, Paul; Saitta, Biagio; Salustino Guimaraes, Valdir; Sanchez Mayordomo, Carlos; Sanmartin Sedes, Brais; Santacesaria, Roberta; Santamarina Rios, Cibran; Santovetti, Emanuele; Sarti, Alessio; Satriano, Celestina; Satta, Alessia; Saunders, Daniel Martin; Savrie, Mauro; Savrina, Darya; Schiller, Manuel; Schindler, Heinrich; Schlupp, Maximilian; Schmelling, Michael; Schmidt, Burkhard; Schneider, Olivier; Schopper, Andreas; Schune, Marie Helene; Schwemmer, Rainer; Sciascia, Barbara; Sciubba, Adalberto; Seco, Marcos; Semennikov, Alexander; Sepp, Indrek; Serra, Nicola; Serrano, Justine; Sestini, Lorenzo; Seyfert, Paul; Shapkin, Mikhail; Shapoval, Illya; Shcheglov, Yury; Shears, Tara; Shekhtman, Lev; Shevchenko, Vladimir; Shires, Alexander; Silva Coutinho, Rafael; Simi, Gabriele; Sirendi, Marek; Skidmore, Nicola; Skwarnicki, Tomasz; Smith, Anthony; Smith, Edmund; Smith, Eluned; Smith, Jackson; Smith, Mark; Snoek, Hella; Sokoloff, Michael; Soler, Paul; Soomro, Fatima; Souza, Daniel; Souza De Paula, Bruno; Spaan, Bernhard; Sparkes, Ailsa; Spradlin, Patrick; Sridharan, Srikanth; Stagni, Federico; Stahl, Marian; Stahl, Sascha; Steinkamp, Olaf; Stenyakin, Oleg; Stevenson, Scott; Stoica, Sabin; Stone, Sheldon; Storaci, Barbara; Stracka, Simone; Straticiuc, Mihai; Straumann, Ulrich; Stroili, Roberto; Subbiah, Vijay Kartik; Sun, Liang; Sutcliffe, William; Swientek, Krzysztof; Swientek, Stefan; Syropoulos, Vasileios; Szczekowski, Marek; Szczypka, Paul; Szilard, Daniela; Szumlak, Tomasz; T'Jampens, Stephane; Teklishyn, Maksym; Tellarini, Giulia; Teubert, Frederic; Thomas, Christopher; Thomas, Eric; van Tilburg, Jeroen; Tisserand, Vincent; Tobin, Mark; Tolk, Siim; Tomassetti, Luca; Topp-Joergensen, Stig; Torr, Nicholas; Tournefier, Edwige; Tourneur, Stephane; Tran, Minh Tâm; Tresch, Marco; Tsaregorodtsev, Andrei; Tsopelas, Panagiotis; Tuning, Niels; Ubeda Garcia, Mario; Ukleja, Artur; Ustyuzhanin, Andrey; Uwer, Ulrich; Vacca, Claudia; Vagnoni, Vincenzo; Valenti, Giovanni; Vallier, Alexis; Vazquez Gomez, Ricardo; Vazquez Regueiro, Pablo; Vázquez Sierra, Carlos; Vecchi, Stefania; Velthuis, Jaap; Veltri, Michele; Veneziano, Giovanni; Vesterinen, Mika; Viaud, Benoit; Vieira, Daniel; Vieites Diaz, Maria; Vilasis-Cardona, Xavier; Vollhardt, Achim; Volyanskyy, Dmytro; Voong, David; Vorobyev, Alexey; Vorobyev, Vitaly; Voß, Christian; Voss, Helge; de Vries, Jacco; Waldi, Roland; Wallace, Charlotte; Wallace, Ronan; Walsh, John; Wandernoth, Sebastian; Wang, Jianchun; Ward, David; Watson, Nigel; Websdale, David; Whitehead, Mark; Wicht, Jean; Wiedner, Dirk; Wilkinson, Guy; Williams, Matthew; Williams, Mike; Wilschut, Hans; Wilson, Fergus; Wimberley, Jack; Wishahi, Julian; Wislicki, Wojciech; Witek, Mariusz; Wormser, Guy; Wotton, Stephen; Wright, Simon; Wyllie, Kenneth; Xie, Yuehong; Xing, Zhou; Xu, Zhirui; Yang, Zhenwei; Yuan, Xuhao; Yushchenko, Oleg; Zangoli, Maria; Zavertyaev, Mikhail; Zhang, Liming; Zhang, Wen Chao; Zhang, Yanxi; Zhelezov, Alexey; Zhokhov, Anatoly; Zhong, Liang; Zvyagin, Alexander

2015-02-04

Using the latest LHCb measurements of time-dependent $C\\!P$ violation in the $B^0_s \\to K^+K^-$ decay, a U-spin relation between the decay amplitudes of $B^0_s \\to K^+K^-$ and $B^0\\to \\pi^+\\pi^-$ decay processes allows constraints to be placed on the angle $\\gamma$ of the unitarity triangle and on the $B^0_s$ mixing phase $-2\\beta_s$. Results from an extended approach, which uses additional inputs on $B^0\\to \\pi^0\\pi^0$ and $B^+\\to \\pi^+\\pi^0$ decays from other experiments and exploits isospin symmetry, are also presented. The dependence of the results on the maximum allowed amount of U-spin breaking is studied. At 68% probability, the value $\\gamma = \\left( 63.5^{\\,+\\, 7.2}_{\\,-\\,6.7} \\right)^\\circ~\\mathrm{modulo}~180^\\circ$ is determined. In an alternative analysis, the value $-2\\beta_s = -0.12 ^{\\,+\\,0.14}_{\\,-\\,0.16}\\,\\,\\mathrm{rad}$ is found. In both measurements, the uncertainties due to U-spin breaking effects up to 50% are included.

Simulation approach to coincidence summing in {gamma}-ray spectrometry

Energy Technology Data Exchange (ETDEWEB)

Dziri, S., E-mail: samir.dziri@iphc.cnrs.fr [Groupe RaMsEs, Institut Pluridisciplinaire Hubert Curien (IPHC), University of Strasbourg, CNRS, IN2P3, UMR 7178, 23 rue de Loess, BP 28, 67037 Strasbourg Cedex 2 (France); Nourreddine, A.; Sellam, A.; Pape, A.; Baussan, E. [Groupe RaMsEs, Institut Pluridisciplinaire Hubert Curien (IPHC), University of Strasbourg, CNRS, IN2P3, UMR 7178, 23 rue de Loess, BP 28, 67037 Strasbourg Cedex 2 (France)

2012-07-15

Some of the radionuclides used for efficiency calibration of a HPGe spectrometer are subject to coincidence-summing (CS) and account must be taken of the phenomenon to obtain quantitative results when counting samples to determine their activity. We have used MCNPX simulations, which do not take CS into account, to obtain {gamma}-ray peak intensities that were compared to those observed experimentally. The loss or gain of a measured peak intensity relative to the simulated peak is attributed to CS. CS correction factors are compared with those of ETNA and GESPECOR. Application to a test sample prepared with known radionuclides gave values close to the published activities. - Highlights: Black-Right-Pointing-Pointer Coincidence summing occurs when the solid angle is increased. Black-Right-Pointing-Pointer The loss of counts gives rise to an approximative efficiency curves, this means a wrong quantitative data. Black-Right-Pointing-Pointer To overcome this problem we need mono-energetic source, otherwise, the MCNPX simulation allows by comparison with the experiment data to get the coincidence summing correction factors. Black-Right-Pointing-Pointer By multiplying these factors by the approximative efficiency, we obtain the accurate efficiency.

Measurement of the beta-gamma directional correlation of the transition 46Sc→46Ti

International Nuclear Information System (INIS)

Krexner, G.

1978-01-01

Measuring the forward - backward asymmetry of the direction of gamma quanta with respect to the direction of a preceding beta particle emission is one of the methods which have been developed over the past twenty years to investigate parity admixtures in nuclear states. Both theoretical calculations and experiments using this method yield very small values for the considered effect. Moreover the accuracy is limited for statistical reasons. Hence there exists a fundamental interest in proving the experimental arrangement to be free of systematic errors. The subject of this work is an experiment checking a six - detector apparatus which has been used to investigate the beta - gamma directional correlation in the decay 203 Hg→ 203 Tl. For the control measurement the transition 46 Sc→ 46 Ti was chosen. The asymmetry coefficient should yield zero and thus furnish evidence of the absence of systematic errors. The necessary 46 Sc source had to meet very restricting requirements. The feasibility of various methods for producing radioactive samples was reviewed; finally a specially designed high vacuum evaporation plant was constructed. The concept of this device and the preparation of the source are dealt with in detail. A preliminary result of the control experiment is given. However, at present a definite interpretation of the obtained values is not possible. (author)

Beta and gamma decay heat evaluation for the thermal fission of 235U

International Nuclear Information System (INIS)

Schenter, G.K.; Schmittroth, F.

1979-01-01

Beta and gamma fission product decay heat curves are evaluated for the thermal fission of 235 U. Experimental data that include beta, gamma, and total measurements are combined with summation calculations based on ENDF/B in a consistent evaluation. Least-squares methods are used that take proper account of data uncertainties and correlations. 4 figures, 2 tables

Field measurement and interpretation of beta doses and dose rates

International Nuclear Information System (INIS)

Selby, J.M.; Swinth, K.L.; Hooker, C.D.; Kenoyer, J.L.

1983-01-01

A large number of portable survey instruments employing G.M., ionization chamber, and scintillation detectors used for gamma measurements are also used for monitoring in beta fields by using removable shields to separate the beta and gamma components of the radiation field. The difference does not correspond to an absorbed dose rate for the beta field due to a variety of factors. Among these factors are the dependence on beta energy, source-detector geometries, mixed fields and variable ambient conditions. Attempting to use such measurements directly can lead to errors as high as a factor of 100. Appropriate calibrations and correction factors can be used to reduce the errors in beta measurements to a tolerable level

The measurement of cross sections of inelastic and transfer reactions with gamma-particle coincidence

International Nuclear Information System (INIS)

Zagatto, V.A.B.; Oliveira, J.R.B.; Pereira, D.; Allegro, P.R.P.; Chamon, L.C.; Cybulska, E.W.; Medina, N.H.; Ribas, R.V.; Rossi Junior, E.S.; Seale, W.A.; Silva, C.P.; Gasques, L.; Toufen, D.L.; Silveira, M.A.G.; Zahn, G.S.; Genezini, F.A.; Shorto, J.M.B.; Lubian, J.; Linares, R.

2011-01-01

Full text: The following work aims to obtain experimental reaction cross sections of inelastic excitation and transfer to excited states reactions (both measured by gamma-particle coincidences) and its comparison with theoretical predictions based in a new model based on the Sao Paulo Potential. The measurements were made at the Pelletron accelerator laboratory of the University of Sao Paulo with the Saci-Perere spectrometer, which consists of 4 a GeHP Compton suppressed gamma detectors and a 4 π charged particle ancillary system with 11ΔΕ - Ε plastic phoswich scintillators (further details about the experimental procedure may be found in: J.R.B. Oliveira et al., XVIII International School on Nuclear Physics, Neutron Physics and Applications (2009). Theoretical angular distribution calculations (using code GOSIA) were performed with a new model based on the Sao Paulo Potential, specifically developed for the inclusion of dissipative processes like deep-inelastic collisions (DIC) considering the Coulomb plus nuclear potential (with the aid of code FRESCO). The experimental cross sections were obtained such as described in J.R.B. Oliveira et al however, in this work, the particle-gamma angular correlations and the vacuum de-alignment effects (caused by hyperfine interaction) were finally added for the 110 Pd inelastic reaction and for the 112 Pd transfer reaction. For these purposes a new code has been developed to assist in the data analysis. We take into account the particle-gamma angular correlations using the scattering amplitudes given by FRESCO, considering the vacuum de-alignment effects as proposed by A. Abragam and R. V. Pound, Phys. Rev. 92, 943 (1953). The theoretical predictions still consider 2 different types of Sao Paulo Potential, the first one has a multiplying factor equals to 1.0 in the real part of the potential and the second considers this factor equals to 0.6, as proposed in D. Pereira, J. Lubian, J.R.B. Oliveira, D.P. de Sousa and L

CaSO4: Dy + Teflon dosimetric pellets for X, beta and gamma radiation detection

International Nuclear Information System (INIS)

Campos, L.L.; Lima, M.F.

1987-08-01

CaSO 4 : Dy + TEFLON dosimetric pellets with high sensitivity and low cost for X, beta and gamma radiation monitoring were studied and developed by the Dosimetric Material Production Laboratory of the Radiological Protection Departament and are disposable for sale. The thickness of the pellets are suitable for X, beta and gamma radiation measurements. The dosimetric properties of these pellets were determined and presented in this work. The results show the usefulness of 0,20mm thick pellets for beta radiation monitoring and 0,80mm thick pellets for x and gamma radiation detection. (Author) [pt

Optimization of plastic scintillator thicknesses for online beta/gamma detection

Directory of Open Access Journals (Sweden)

Pourtangestani K.

2012-04-01

Full Text Available For efficient beta detection in a mixed beta gamma field, Monte Carlo simulation models have been built to optimize the thickness of a plastic scintillator, used in a whole body monitor. The simulation has been performed using the MCNP/X code for different thicknesses of plastic scintillator from 150 μm to 600 μm. The relationship between the thickness of the scintillator and the efficiency of the detector has been analyzed. For 150 μm thickness, an experimental investigation has been conducted with different beta sources at different positions on the scintillator and the counting efficiency of the unit has been measured. Evaluated data along with experimental ones have been discussed. A thickness of 300 μm to 500 μm has been found to be the optimum thickness for high efficiency beta detection in the presence of low energy gamma-rays.

Selection and evaluation of gamma decay standards for detector calibration using coincidence method

International Nuclear Information System (INIS)

Hlavac, S.

2000-01-01

Coincidence method for calibration of gamma detectors using suitable calibration standards with two cascading gamma rays is analyzed. From the list of recommended gamma ray standards currently under reevaluation by the CRP, 14 radionuclides were selected as the potential source candidates for the coincidence method. The following sources were selected 24 Na, 46 Sc, 60 Co, 66 Ga, 75 Se, 88 Y, Nb 94 , 111 In, 123m Te, 133 Ba, 134 Cs, 152 Eu, 154 Eu and 207 Bi. Reaction 11 B (p,γ) 12 C* was also selected as a source of high energy gamma rays. Experimental data on angular correlation coefficients for selected sources were collected from the literature and evaluated according to the recommended procedure. Theoretical angular correlation coefficients were calculated and compared to the evaluated data. (author)

Determination of gross gamma and gross beta activities in liquid effluent samples. Phase I

International Nuclear Information System (INIS)

Curtis, K.E.; Sood, S.P.

1985-08-01

Several inadequacies in the presently used procedures for gross gamma and gross beta measurements in aqueous wastes have been identified. Both the presence of suspended particulate activity and the use of cesium-137 as a calibration standard can cause gross gamma measurements to overestimate the actual activity in the sample. At the same time, sample preparation for the determination of gross beta activities causes large losses of radioiodine before the measurement step and the presence of solid material can cause a serious decrease in the beta counting efficiency. A combination of these errors could result in large discrepancies between the results obtained by the two measurement methods. Improved procedures are required to overcome these problems

Determination of the absolute activity by the coincidences 4πβ-γ method

International Nuclear Information System (INIS)

Urcelay Silva, A.J.

1975-01-01

The 4π beta-gamma coincidence method for absolute determination of activities is extremely important in the production of high-precision radioactive sources. By means of this method it is possible to obtain absolute measurements of decay to within 0.1%. Thanks to the high efficiency of the 4π counter, most of the corrections required - background, random coincidences, dead time, decay scheme and detector efficiency - are small. The paper describes the experimental set-up showing the pulses in the two branches of the system, together with the conditions under which the 4πbeta flux detector functions. To determine whether the system was functioning satisfactorily, the activity of four cobalt-60 standards (supplied by the International Bureau of Weights and Measures based at Sevres in France) was determined and the differences obtained were less than 0.5% with respect to the certificates accompanying the sources. Alterations to the flux detector are suggested so that higher accuracy may be obtained. (author)

Gamma-gamma angular correlation measurement in the 100 Ru

International Nuclear Information System (INIS)

Kenchian, G.

1990-01-01

An angular correlation automatic spectrometer with two Ge(Li) detectors has been developed. The spectrometer moves automatically, controlled by a microcomputer. The gamma-gamma directional angular correlations of coincidence transitions have been measured in 100 Ru nuclide, following the β + and electron capture of 100 Rh. The 100 Rh source has been produced with 100 Ru(p,n) 100 Rh reaction, using the proton beam of the Cyclotron Accelerator insiding in 100 Ru isotope. (author)

Simulated progress in double-beta decay

International Nuclear Information System (INIS)

Miley, H.S.; Arthur, R.J.; Avignone, F.T.

1993-09-01

A Monte Carlo code has been developed to accurately simulate double-beta decay measurements. Coincident gamma rays, beta spectra, and angular correlations have been added to adequately simulate a complete 100 Mo nuclear decay and provide corrections to experimentally determined detector efficiencies. This code has been used to strip certain low-background spectra obtained in the Homestake gold mine in Lead, SD, for the purpose of extremely sensitive materials assay for the construction of new, large, enriched germanium detectors. Assays as low as 9 μBq/g of 210 Pb in lead shielding were obtained

Procedure for the elaboration of extended sources beta and/or gamma emitting

International Nuclear Information System (INIS)

Tejera R, A.; Cortes P, A.; Becerril V, A.

1991-12-01

In the laboratory of radioactive standards they have been come manufacturing punctual sources gauged gamma emitting during several years. Before the demand of extended radioactive homogeneous sources of beta particles emitting, in particular with nuclides that are simultaneously gamma and beta emitting, it was designed a procedure for it elaboration based on the one that we use at the moment for the elaboration of the punctual gamma sources. This procedure consists on the integration of a compact group of this type of sources on a single extended support, sealed one of its faces with a film of transparent material in satisfactory grade to the beta particles. In this work this procedure is described and it is applied in the elaboration of two sources that its were requested by the Laguna Verde Central (CFE), one with area of 20 cm 2 and the other one of 100 cm 2 . The homogeneity, measure as the dispersion of the activities of the aliquot ones distributed in the active surfaces was inside 2%. The percentage of attenuation of the beta particles was also measured by the film (window) with the one that the sources were sealed. (Author)

Value of coincidence gamma camera PET for diagnosing head and neck tumors: functional imaging and image coregistration

International Nuclear Information System (INIS)

Dresel, S.; Brinkbaeumer, K.; Schmid, R.; Hahn, K.

2001-01-01

54 patients suffering from head and neck tumors (30 m, 24 f, age: 32-67 years) were examined using dedicated PET and coincidence gamma camera PET after injection of 185-350 MBq [ 18 F]FDG. Examinations were carried out on the dedicated PET first (Siemens ECAT Exact HR+) followed by a scan on the coincidence gamma camera PET (Picker Prism 2000 XP-PCD, Marconi Axis g-PET 2 AZ). Dedicated PET was acquired in 3D mode, coincidence gamma camera PET was performed in list mode using an axial filter. Reconstruction of data was performed iteratively on both, dedicated PET and coincidence gamma camera PET. All patients received a CT scan in multislice technique (Siemens Somatom Plus 4, Marconi MX 8000). Image coregistration was performed on an Odyssey workstation (Marconi). All findings have been verified by the gold standard histology or in case of negative histology by follow-up. Results: Using dedicated PET the primary or recurrent lesion was correctly diagnosed in 47/48 patients, using coincidence gamma camera PET in 46/48 patients and using CT in 25/48 patients. Metastatic disease in cervical lymph nodes was diagnosed in 17/18 patients with dedicated PET, in 16/18 patients with coincidence gamma camera PET and in 15/18 with CT. False-positive results with regard to lymph node metastasis were seen with one patient for dedicated PET and hybrid PET, respectively, and with 18 patients for CT. In a total of 11 patients unknown metastatic lesions were seen with dedicated PET and with coincidence gamma camera PET elsewhere in the body (lung: n = 7, bone: n = 3, liver: n = 1). Additional malignant disease other than the head and neck tumor was found in 4 patients. (orig.) [de

Beta/gamma test problems for ITS

International Nuclear Information System (INIS)

Mei, G.T.

1993-01-01

The Integrated Tiger Series of Coupled Electron/Photon Monte Carlo Transport Codes (ITS 3.0, PC Version) was used at Oak Ridge National Laboratory (ORNL) to compare with and extend the experimental findings of the beta/gamma response of selected health physics instruments. In order to assure that ITS gives correct results, several beta/gamma problems have been tested. ITS was used to simulate these problems numerically, and results for each were compared to the problem's experimental or analytical results. ITS successfully predicted the experimental or analytical results of all tested problems within the statistical uncertainty inherent in the Monte Carlo method

{beta} {gamma} porch detector; Detecteur portique {beta} {gamma}

Energy Technology Data Exchange (ETDEWEB)

Roulet, R [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

1963-07-01

This device is to be placed at the outside of reactors, hot laboratories and others where radioactive products are treated; it is intended to give the alarm when someone, passing through the porch is greatly contaminated, or carries, without his knowing, a radioactive substance. Being to be used in places where there might be an important ground noise, this device is provided with an automatic offset of this noise; an adjusting system of sensitivity allows to obtain a 15 {mu}Ci in {gamma} and 10 {mu}Ci in {beta} radioactive source, passing through the porch at the normal speed at which man is walking. A battery, set in buffer, allows working of the device, even when current is off. (author) [French] Cet appareil est destine a etre place a la sortie des reacteurs, laboratoires chauds ou autres laboratoires travaillant sur des produits radioactifs; son but est de donner une alarme lorsque quelqu'un, passant sous le portique, presente une forte contamination, ou surtout transporte par inadvertance un corps radioactif. Cet appareil devant etre utilise dans les lieux ou peut regner un bruit de fond important, possede une compensation automatique de ce bruit de fond; un reglage de la sensibilite permet d'obtenir au mieux un declenchement pour une source. de 15 {mu}Ci en {gamma} et 10 {mu}Ci en {beta} passant sous le portique a la vitesse normale d'un homme qui marche. Une batterie montee en tampon permet a l'appareil de fonctionner meme en cas de coupure de courant. (auteur)

Study of $\\beta$-delayed neutron decay of $^{8}$He

CERN Multimedia

The goal of the present proposal is to study $\\beta$-delayed neutron decay branch of $^{8}$He. The energy spectra of the emitted neutrons will be measured in the energy range of 0.1 – 6 MeV using the VANDLE spectrometer. Using coincident $\\gamma$-ray measurement, components of the spectrum corresponding to transitions to the ground- and first- excited states of $^{7}$Li will be disentangled. The new data will allow us to get a more complete picture of the $\\beta$-decay of $^{8}$He and to clarify the discrepancy between the B(GT) distributions derived from the $\\beta$-decay and $^{8}$He(p, n)$^{8}$Li reaction studies.

Ornithogalum virens as a plant assay for beta and gamma radiation effects

International Nuclear Information System (INIS)

Herron, V.J.

1979-01-01

The purpose of this study was to determine if the monocotyledonous angiosperm, Ornithogalum virens (Quintanilha and Cabral, 1947), could be used in such a biological assay system. After exposing O. virens plants to acute ( 60 Co) and chronic ( 137 Cs) gamma radiation and internal beta radiation ( 32 P), lethality (LD 50 , LD 100 ), growth inhibition, and chromosome aberrations were investigated. The LD 50 and LD 100 for acute gamma radiation were estimated to be between 0.91 to 1.8 krad and less than 3.6 krad, respectively. Though growth inhibition and abnormal growth were observed in the acute and chronic gamma radiation studies, the changes in the growth of the plants were so variable that these parameters were found to be unreliable measures of radiation effects. Chromosome aberrations were a more reliable measure of radiation damage because linear relationships between total aberrations and dose were found for both gamma and beta radiation

Spectroscopy of {sup 189,187}Pb from gamma-FMA coincidences

Energy Technology Data Exchange (ETDEWEB)

Janssens, R.V.F.; Davids, C.N.; Blumenthal, D. [and others

1995-08-01

The very neutron-deficient Pb isotopes are of much current interest because they exhibit shape coexistence between a spherical groundstate and a deformed prolate excited configuration located very low in excitation energy. Last year the nucleus {sup 186}Pb was studied at the FMA in an FMA-{gamma}-{gamma} coincidence experiment. The purpose of the present measurement was to delineate, for the first time, the groundstate and near groundstate excitations in the odd Pb isotopes {sup 189,187}Pb in order to identify the orbitals which have an important role in driving the nuclear shape. The experiment was performed only very recently at the FMA with 10 Compton-suppressed Ge detectors from the Argonne Notre Dame BGO Gamma-Ray facility. {sup 187}Pb was studied with the {sup 155}Gd({sup 36}Ar,4n) reaction at 179 MeV, while {sup 189}Pb was reached with the {sup 158}Gd({sup 36}Ar,5n) reaction at the same beam energy. The analysis just began. It can already be stated that transitions in both Pb isotopes were identified and that it should be possible to establish level schemes. The presence of possible isomeric states in {sup 189}Pb will be checked in a follow-up experiment planned in Canberra. A similar measurement on {sup 187}Pb appears very difficult because of the very small cross section involved.

gamma-ray emission probabilities of sup 1 sup 9 sup 3 Os

CERN Document Server

Marnada, N; Ueda, N; Ikeda, K; Hayashi, N

2002-01-01

Precise measurements of disintegration rates by using a 4 pi beta-gamma coincidence apparatus have resulted in improved certainties of the principal gamma-ray emission probabilities of sup 1 sup 9 sup 3 Os. Most of the uncertainties are less than 1%, whereas the uncertainties of emission probabilities evaluated in the Nuclear Data Sheets (83 (1998) 921) are more than 6%. The precision is improved for the beta-ray branching ratio for direct transition to the ground state and the value is larger than the evaluated value by about 6%.

Beta-spectrometer with Si-detectors for the study of 144Ce-144Pr decays

Science.gov (United States)

Alexeev, I. E.; Bakhlanov, S. V.; Bazlov, N. V.; Chmel, E. A.; Derbin, A. V.; Drachnev, I. S.; Kotina, I. M.; Muratova, V. N.; Pilipenko, N. V.; Semyonov, D. A.; Unzhakov, E. V.; Yeremin, V. K.

2018-05-01

Here we present the specifications of a newly developed beta-spectrometer, based on full absorption Si(Li) detector and thin transmission detector, allowing one to perform efficient separation beta-radiation and accompanying X-rays and gamma radiation. Our method is based on registration of coincident events from both detectors. The spectrometer can be used for precision measurements of various beta-spectra, namely for the beta-spectrum shape study of 144Pr, which is considered to be an advantageous anti-neutrino source for sterile neutrino searches.

Time-of-flight spectrometer for the measurement of gamma correlated neutron spectra

International Nuclear Information System (INIS)

Andriashin, A.V.; Devkin, B.V.; Lychagin, A.A.; Minko, J.V.; Mironov, A.N.; Nesterenko, V.S.; Sztaricskai, T.; Petoe, G.; Vasvary, L.

1986-01-01

A time-of-flight spectrometer for the measurement of gamma correlated neutron spectra from (n,xnγ) reactions is described. The operation and the main parameters are discussed. The resolution in the neutron channel is 2.2 ns/m at the 150 keV neutron energy threshold. A simultaneous measurement of the time-of-flight and amplitude distributions makes it possible to study gamma correlated neutron spectra as well as the prompt gamma spectra in coincidence with selected energy neutrons. In order to test the spectrometer, measurements of the neutron spectrum in coincidence with the 846 keV gamma line of 56 Fe were carried out at an incident neutron energy of 14.1 MeV. (Auth.)

Responses of a grassland arthropod community to chronic beta and gamma radiation

International Nuclear Information System (INIS)

Styron, C.E.; Dodson, G.J.; Beauchamp, J.J.; Miller, F.L. Jr.

1976-01-01

A long-term project was initiated in 1968 at Oak Ridge National Laboratory to assess effects of mixed beta and gamma radiation from simulated fallout on a grassland ecosystem. Beta and gamma radiation dose rates in microhabitats of the experimentally contaminated enclosure were measured with LiF thermoluminescent microdosimeters. Extensive statistical analyses of data on numbers of individuals collected for each of 76 arthropod and 2 molluscan taxa have identified no lasting significant changes in similarity or species diversity of experimental versus control communities as the result of the long-term irradiation at low dose rates. Natural fluctuations in community dynamics obscured any possible radiation effects. Thus, the apparent threshold for mixed beta and gamma radiation inducing changes in community structure must be above the exposure rate range of 2.3 to 13 rad/day delivered during the 5 yr of observation. Establishing such a threshold is of importance in assessing the impact of communities subjected to chronic, low level environmental exposure to ionizing radiation

Particle-gamma coincidence measurements in /sup 12/C+/sup 12/C and /sup 12/C+Pb collisions at 2. 1 GeV/nucleon incident energy

Energy Technology Data Exchange (ETDEWEB)

Roche, G.; Koontz, R.; Mulera, T.; Pugh, H.G.; Schroeder, L.S. (Lawrence Berkeley Lab., CA (USA)); Hallman, T.; Madansky, L. (Johns Hopkins Univ., Baltimore, MD (USA)); Carroll, J. (California Univ., Los Angeles (USA)); Chang, C.C. (Maryland Univ., College Park (USA)); Kirk, P.N.

1985-06-24

A particle-gamma coincidence experiment has been performed with a 2.1 GeV per nucleon /sup 12/C beam from the Bevalac. Data were taken with C and Pb targets. The ..gamma..-ray spectra are almost independent of the energy or the kind of charged particles detected in coincidence, mainly protons and deuterons. These ..gamma..-ray spectra are interpreted as resulting from ..pi../sup 0/ decay, and are consistent with known ..pi../sup 0/ production rates. A search for a possible decay of singly-charged anomalons into a gamma and a deuteron (or unbound proton-neutron system) has been done by studying the ..gamma..p and ..gamma..d invariant mass distributions. The upper limits for such a process are found to be 2 to 20% of the deuteron production rate, for anomalon masses for 200 to 400 MeV above the deuteron mass, with an anomalon mean lifetime of up to 10/sup -9/ s, depending on which kind of decay process is considered.

Coincidence gamma-ray spectrometry

DEFF Research Database (Denmark)

Markovic, Nikola; Roos, Per; Nielsen, Sven Poul

2017-01-01

Gamma-ray spectrometry with high-purity germanium (HPGe) detectors is often the technique of choice in an environmental radioactivity laboratory. When measuring environmental samples associated activities are usually low so an important parameter that describes the performance of the spectrometer...... for a nuclide of interest is the minimum detectable activity (MDA). There are many ways for lowering the MDAs in gamma spectrometry. Recently, developments of fast and compact digital acquisition systems have led to growing number of multiple HPGe detector spectrometers. In these applications all detected...

Time-of-flight spectrometer for the measurement of gamma correlated neutron spectra

International Nuclear Information System (INIS)

Andryashin, A.V.; Devlein, B.V.; Lychagin, A.A.; Minko, Y.V.; Mironov, A.N.; Nesterenko, V.S.

1986-01-01

A time-of-flight spectrometer for the measurement of gamma correlated neutron spectra form (n,xnγ) reactions is described. The operation and the main parameters are discussed. The resolution in the neutron channel is 2.2 ns/m at the 150 keV neutron energy threshold. A simultaneous measurement of the time-of-flight and amplitude distributions makes it possible to study gamma correlated neutron spectra as well as the prompt gamma spectra in coincidence with selected energy neutrons. In order to test the spectrometer, measurements of the neutron spectrum in coincidence with the 846 keV gamma line of 56 Fe were carried out at an incident neutron energy of 14.1 MeV. (author). 3 figs., 6 refs

Recent progress with digital coincidence counting

International Nuclear Information System (INIS)

Butcher, K.S.A.; Watt, G.C.; Alexiev, D.

1999-01-01

Digital Coincidence Counting (DCC) is a new technique, based on the older method of analogue coincidence counting. It has been developed by ANSTO as a faster more reliable means of determining the activity of ionising radiation samples. The technique employs a dual channel analogue to digital converter acquisition system for collecting pulse information from a 4Π beta detector and a NaI(Tl) gamma detector. The digitised pulse information is stored on a high speed hard disk and timing information for both channels is also stored. The data may subsequently be recalled and analysed using software based algorithms. The system is operational and results are now being routinely collected and analysed. Some of the early work is presented for Co-60, Na-22 and Sm-153

The two plastic scintillator measuring system HBG-2

International Nuclear Information System (INIS)

Tran Manh Toan; Nguyen Trieu Tu

1992-01-01

The beta-gamma measuring system HBG-2 is described. It consist of: 1. Two 40mm Φ x 3mm plastic scintillators, a beta-filter, a shielded cell, and a coincidence circuit; 2. Four counting channels in which one is reversible. A device is capable of measuring low-level activity. Some special measuring methods provided by the equipment are presented, too. (author). 6 refs, 3

The study of the properties of nuclei far from the beta stability line

International Nuclear Information System (INIS)

Lizurej, H.I.

1980-01-01

A complex of setups for measuring the lifetime of excited states of nuclei by the method of delayed electron-gamma and gamma-gamma coincidences in the range 10 -10 -10 -6 s is presented. The methods allowing for a substantial increase in the accuracy and efficiency of obtaining experimental data are developed. The procedures of measuring and analysing the multicomponent beta spectra with taking into account the instrumental effect which distorts the measured spectra are developed. Results of investigating the positron decay and determining the mass difference Qsub(B)+ for nuclei with Tsub(1/2)>20 min by the method of measuring the positron end-point energy are presented. The nano- and subnanosecond isomers for short-lived isotopes far from the beta stability line have been investigated. Probabilities of the electromagnetic transitions which depopulate the low-lying excited states in 151 Tb, 153 Dy, 160 Tm, sup(157,159,161)Er have been determined and analysed. (author)

Testing gravitational parity violation with coincident gravitational waves and short gamma-ray bursts

International Nuclear Information System (INIS)

Yunes, Nicolas; O'Shaughnessy, Richard; Owen, Benjamin J.; Alexander, Stephon

2010-01-01

Gravitational parity violation is a possibility motivated by particle physics, string theory, and loop quantum gravity. One effect of it is amplitude birefringence of gravitational waves, whereby left and right circularly polarized waves propagate at the same speed but with different amplitude evolution. Here we propose a test of this effect through coincident observations of gravitational waves and short gamma-ray bursts from binary mergers involving neutron stars. Such gravitational waves are highly left or right circularly polarized due to the geometry of the merger. Using localization information from the gamma-ray burst, ground-based gravitational wave detectors can measure the distance to the source with reasonable accuracy. An electromagnetic determination of the redshift from an afterglow or host galaxy yields an independent measure of this distance. Gravitational parity violation would manifest itself as a discrepancy between these two distance measurements. We exemplify such a test by considering one specific effective theory that leads to such gravitational parity violation, Chern-Simons gravity. We show that the advanced LIGO-Virgo network and all-sky gamma-ray telescopes can be sensitive to the propagating sector of Chern-Simons gravitational parity violation to a level roughly 2 orders of magnitude better than current stationary constraints from the LAGEOS satellites.

Coincidence corrections for a multi-detector gamma spectrometer

Energy Technology Data Exchange (ETDEWEB)

Britton, R., E-mail: r.britton@surrey.ac.uk [University of Surrey, Guildford GU2 7XH (United Kingdom); AWE, Aldermaston, Reading, Berkshire RG7 4PR (United Kingdom); Burnett, J.L.; Davies, A.V. [AWE, Aldermaston, Reading, Berkshire RG7 4PR (United Kingdom); Regan, P.H. [University of Surrey, Guildford GU2 7XH (United Kingdom)

2015-01-01

List-mode data acquisition has been utilised in conjunction with a high-efficiency γ–γ coincidence system, allowing both the energetic and temporal information to be retained for each recorded event. Collected data is re-processed multiple times to extract any coincidence information from the γ-spectroscopy system, correct for the time-walk of low-energy events, and remove accidental coincidences from the projected coincidence spectra. The time-walk correction has resulted in a reduction in the width of the coincidence delay gate of 18.4±0.4%, and thus an equivalent removal of ‘background’ coincidences. The correction factors applied to ∼5.6% of events up to ∼500 keV for a combined {sup 137}Cs and {sup 60}Co source, and are crucial for accurate coincidence measurements of low-energy events that may otherwise be missed by a standard delay gate. By extracting both the delay gate and a representative ‘background’ region for the coincidences, a coincidence background subtracted spectrum is projected from the coincidence matrix, which effectively removes ∼100% of the accidental coincidences (up to 16.6±0.7% of the total coincidence events seen during this work). This accidental-coincidence removal is crucial for accurate characterisation of the events seen in coincidence systems, as without this correction false coincidence signatures may be incorrectly interpreted.

Maternal and cord plasma concentrations of beta-lipotrophin, beta-endorphin and gamma-lipotrophin at delivery; effect of analgesia.

Science.gov (United States)

Browning, A J; Butt, W R; Lynch, S S; Shakespear, R A; Crawford, J S

1983-12-01

Maternal venous plasma concentrations of beta-LPH, beta-EP and gamma-LPH were compared in (i) patients undergoing vaginal delivery, 11 with an epidural block and 13 with pethidine and nitrous oxide or no analgesics; (ii) patients delivered by caesarean section, 7 under epidural block and 8 under general anaesthesia. Patients delivered by either method under epidural block had significantly lower levels of all three peptides than those receiving no epidural. There were significant negative correlations between umbilical vein beta-LPH, beta-EP and gamma-LPH concentrations and umbilical artery pH and positive correlations between beta-LPH and beta-EP but not gamma-LPH and cord PCO2 in 29 patients. There was no relation between cord levels of any of the three peptides and the method of analgesia or the route of delivery. Although concentrations of all three peptides were closely correlated to one another in either maternal or cord plasma, there was no relationship between maternal and fetal levels.

Measurement of gross beta radioactivity in high-level liquid waste

International Nuclear Information System (INIS)

Lu Feng; Lin Cansheng; Zhang Xianzi; Chen Guoan; Zhang Chonghai

1992-01-01

Using beta plastic scintillation counter of low level background, gross beta radioactivity of twelve samples for high-level liquid waste is determined directly. Beta efficiency curves of plastic scintillation counter for four mass thickness are calibrated in advance. Determining gross beta radioactivity, gross efficiency of the scintillation counter for various energy beta ray is calculated via weighted mean method with the ratio of radioactivity for each nuclide. The ratio of radioactivity for nuclides which have gamma disintegration is determined in terms of the radioactivity measured by gamma spectrometer. The ratio of the radioactivity for 90 Sr which has purity beta disintegration is calculated in terms of half life time approximation. The ratio of the radioactivity for 147 Pm which also has purity disintegration is calculated by means of apparent cooling-time approximation. The uncertainty of results for the present work is about +-15%

Rat beta-LPH, gamma-LPH and beta-endorphin biosynthesized by isolated cells of pars intermedia and pars distalis

International Nuclear Information System (INIS)

Gianoulakis, C.; Seidah, N.G.; Routhier, R.; Chretien, M.

1980-01-01

Rats pars intermedia cells were incubated for 3 h with the following amino-acids: a) 35 S-methionine and 3 H-phenylalamine; b) 3 H-valine; and c) 3 H-valine and 3 H-lysine. Radioactive gamma-lipotropin, beta-lipotropin and beta-endorphin were purified on carboxy- methyl-cellulose and characterized by polyacrylamide disc gel electrophoresis af pH 4.5, molecular weight estimation and microsequencing. Rat gamma-lipotropin was shown to differ slightly from ovine gamma-lipotropin in its NH 2 -terminal amino acid sequence, in containing no methionine and having phenylalanine at position 6, valine at positions 13 and 27, and lysine at position 20. The same variations were observed in the sequence of rat beta-lipotropin, while rat beta-endorphin was shown to be identical to the ovine beta-endorphin. Following a 3-h pulse of rat pars distalis, the cells were extracted with care to avoid beta-lipotropin degradation by proteolytic enzymes. A peptide was purified and identified to be rat beta-endorphin, thus demonstrating that beta-endorphin is biosynthesized in pars distalis and is not an extraction artifact. (author)

Measurement of Time-Dependent CP-Violating Asymmetriesand Constraints on sin(2 beta+gamma) withPartial Reconstruction of B to D*-+pi+- Decays

Energy Technology Data Exchange (ETDEWEB)

Aubert, B.

2005-04-19

We present a measurement of the time-dependent CP-violating asymmetries in decays of neutral B mesons to the final states D*{sup {-+}}{pi}{sup {+-}}, using approximately 232 million B{bar B} events recorded by the BABAR experiment at the PEP-II e{sup +}e{sup -} storage ring. Events containing these decays are selected with a partial reconstruction technique, in which only the high-momentum {pi}{sup {+-}} from the B decay and the low-momentum {pi}{sup {-+}} from the D*{sup {-+}} decay are used. We measure the parameters related to 2{beta} + {gamma} to be a{sub D*{pi}} = -0.034 {+-} 0.014 {+-} 0.009 and c{sub D*{pi}}{sup {ell}} = -0.019 {+-} 0.022 {+-} 0.013. With some theoretical assumptions, we interpret our results in terms of the lower limits |sin(2{beta} + {gamma})| > 0.62 (0.35) at 68% (90%) confidence level.

Skin dose assessment in routine personnel beta/gamma dosimetry

International Nuclear Information System (INIS)

Christensen, P.

1980-01-01

The International Commission on Radiological Protection (Publication 26) has recommended a tissue depth of 5 to 10 mg.cm -2 for skin dose assessments. This requirement is generally not fulfilled by routine monitoring procedures because of practical difficulties in using very thin dosemeters with low sensitivity and therefore a high minimum detectable dose. Especially for low-energy beta-ray exposures underestimations of the skin dose by a factor of more than ten may occur. Low-transparent graphite-mixed sintered LiF and Li 2 B 4 0 7 : Mn dosemeters were produced which show a skin-equivalent response to beta and gamma exposures over a wide range of energies. These have found wide-spread application for extremity dosimetry but have not yet been generally introduced in routine personnel beta/gamma monitoring. The following adaptations of existing routine monitoring systems for improved skin dose assessments have been investigated: 1) Placement of a supplementary, thin, skin-dose equivalent dosemeter in the TLD badge to give additional information on low-energy exposures. 2) Introduction of a second photomultiplier in the read-out chamber which enables a simultaneous determination of emitted TL from both sides of the dosemeter separately. This method makes use of the selfshielding of the dosemeter to give information on the low-energy dose contribution. 3) By diffusion of Li 2 B 4 0 7 into solid LiF-dosemeters it was possible to produce a surface layer with a new distinct glow-peak at about 340 deg C which is not present in the undiffused part of the LiF chip, and which can be utilized for the assessment of the skin-dose. Data on energy response and accuracy of dose measurement for beta/gamma exposures are given for the three methods and advantages and disadvantages are discussed (H.K.)

Prototype system for proton beam range measurement based on gamma electron vertex imaging

Energy Technology Data Exchange (ETDEWEB)

Lee, Han Rim [Neutron Utilization Technology Division, Korea Atomic Energy Research Institute, 111, Daedeok-daero 989beon-gil, Yuseong-gu, Daejeon 34057 (Korea, Republic of); Kim, Sung Hun; Park, Jong Hoon [Department of Nuclear Engineering, Hanyang University, Seongdong-gu, Seoul 04763 (Korea, Republic of); Jung, Won Gyun [Heavy-ion Clinical Research Division, Korean Institute of Radiological & Medical Sciences, Seoul 01812 (Korea, Republic of); Lim, Hansang [Department of Electronics Convergence Engineering, Kwangwoon University, Seoul 01897 (Korea, Republic of); Kim, Chan Hyeong, E-mail: chkim@hanyang.ac.kr [Department of Nuclear Engineering, Hanyang University, Seongdong-gu, Seoul 04763 (Korea, Republic of)

2017-06-11

In proton therapy, for both therapeutic effectiveness and patient safety, it is very important to accurately measure the proton dose distribution, especially the range of the proton beam. For this purpose, recently we proposed a new imaging method named gamma electron vertex imaging (GEVI), in which the prompt gammas emitting from the nuclear reactions of the proton beam in the patient are converted to electrons, and then the converted electrons are tracked to determine the vertices of the prompt gammas, thereby producing a 2D image of the vertices. In the present study, we developed a prototype GEVI system, including dedicated signal processing and data acquisition systems, which consists of a beryllium plate (= electron converter) to convert the prompt gammas to electrons, two double-sided silicon strip detectors (= hodoscopes) to determine the trajectories of those converted electrons, and a plastic scintillation detector (= calorimeter) to measure their kinetic energies. The system uses triple coincidence logic and multiple energy windows to select only the events from prompt gammas. The detectors of the prototype GEVI system were evaluated for electronic noise level, energy resolution, and time resolution. Finally, the imaging capability of the GEVI system was tested by imaging a {sup 90}Sr beta source, a {sup 60}Co gamma source, and a 45-MeV proton beam in a PMMA phantom. The overall results of the present study generally show that the prototype GEVI system can image the vertices of the prompt gammas produced by the proton nuclear interactions.

Beta decay of twelve light neutron-rich isotopes from 17C to 40S

International Nuclear Information System (INIS)

Dufour, J.P.; Del Moral, R.; Fleury, A.; Hubert, F.; Jean, D.; Pravikoff, M.S.; Geissel, H.; Schmidt, K.H.

1986-07-01

The results reported here have been obtained with an 40 Argon beam on a Be target. The separated nuclei were implanted in a catcher foil placed in between a thin scintillator detecting the betas and a high volume Ge detector; only gammas in coincidence with betas were recorded. Results for the gamma energies and the half-lives of the observed isotopes are given

Beta-decay half-lives and level ordering of sup 1 sup 0 sup 2 sup m sup , sup g Rh

CERN Document Server

Shibata, M; Itoh, S; Itoh, S; Yamamoto, H; Kawade, K; Kasugai, Y; Ikeda, Y

1998-01-01

Beta-decay half-lives of the ground state and an isomer of sup 1 sup 0 sup 2 Rh have been determined 207.3(17) d and 3.742(10) y, respectively, by gamma-ray decay curves following each beta-decay. It has been found that a state (2 sup -) which has a shorter half-life (207.3 d) is the ground state from the result that the half-life of the 41.9 keV isomeric gamma-transition was equal to 3.742 y. It has also been confirmed that the 41.9 keV transition is certainly an isomeric transition with X-gamma coincidence measurement.

Separate assessment of natural beta and gamma dose-rates with TL from α-Al2O3:C single-crystal chips

International Nuclear Information System (INIS)

Kalchgruber, R.; Wagner, G.A.

2006-01-01

A measurement procedure was developed for fast and separate assessment of beta and gamma dose-rates in natural sediments using highly sensitive α-Al 2 O 3 :C single-crystal chips. The dosemeters were buried for periods from two days to three weeks in sediments with different layer structure and homogeneity. For each measurement, a pair of dosemeters was buried, in order to assess beta and gamma dose-rates separately. One dosemeter was wrapped only in thin plastic foil to shield it from alpha radiation, thus measuring beta + gamma components. The second one, used for the gamma component only, was packed additionally in a 1mm copper container for absorption of beta radiation. For calibration, another set of dosemeters was buried in reference soil with a well-known dose-rate and similar content of radioactive nuclides. By comparing the thermally stimulated luminescence signals from the dosemeters the gamma dose-rate and also, by subtraction, the beta dose-rate in the unknown soil could be determined. The calculated uncertainties were 5-7% and 10%, respectively. The resulting dose-rates for homogeneous and inhomogeneous media were compared with the results obtained by Ge- and on-site NaI-gamma-ray spectrometry. An agreement within 2σ-error limits was found for homogeneous media after only few days of exposure

PC based alpha, beta and gamma counting system

International Nuclear Information System (INIS)

Bhattacharya, S.; Gopalakrishnan, K.R.; Bairi, B.R.

1992-01-01

In the field of radiation protection and safety a large number of samples have to be assayed for estimation of their radioactivity at various stages in nuclear fuel. A PC based alpha, beta and gamma counting system has been designed for the above application. The system is fully automatic and requires minimum of operator intervention. The main units in the system are detector and pulse processing electronics, sample changer and assembly and IBM PC interface and supporting software. The main function of interface is to control the sample changer which is basically loading and unloading of sample, data acquisition and further processing by software. The pulses from detector are analysed in a pulse shape discriminator. A pulse identified as an alpha, beta or gamma event is converted to digital pulse. These digital pulses are accumulated in the three channels on PC interface each corresponding to alpha, beta and gamma. The sample movements are controlled by interface depending upon sample position. The software has been developed so as to maintain user friendliness and convenience of the operator. Various selection modes for parameters and operation of system provide lot of flexibility in operation of the system. (author). 1 fig

Absolute measurement of 85Sr

International Nuclear Information System (INIS)

Miyahara, Hiroshi; Watanabe, Tamaki

1978-01-01

An extension of 4πe.x-γ coincidence technique is described to measure the absolute disintegration rate of 85 Sr. This nuclide shows electron capture-gamma decay, and 514keV level of 85 Rb is a meta-stable state with half life of 0.958 μsec. Therefore, the conventional 4 πe.x-γ coincidence technique with about 1 μsec of resolution time can not be applied to this nuclide. To measure the absolute disintegration rate of this, the delayed 4 πe.x-γ coincidence technique with two different resolution time has been used. The disintegration rate was determined from four counting rates of electron-x ray, gamma ray and two coincidences, and the true disintegration rate could be obtained by extraporation of the electron-x ray detection efficiency to 1. Two resolution time appearing in the calculation formulas were determined from the chance coincidence between electron-x ray and delayed gamma ray signals. When the coincidence countings with three different resolution time were carried out by one coincidence circuit, the results calculated from all combinations did not agree each other. However, when the two coincidence circuits of the same type were used to fix the resolution time, a good coincidence absorption function was obtained and the disintegration rate was determined with accuracy of +- 0.5%. To evaluate the validity of the results the disintegration rates were measured by two NaI (Tl) scintillation detectors whose gamma-ray detection efficiency was previously determined and both results were agreed within accuracy of +- 0.5%. This method can be applied with nearly same accuracy for the beta-gamma decay nuclide possessing a meta-stable state of the half life below about 10 μsec. (auth.)

Vibrational and chiroptical spectroscopic characterization of gamma-turn model cyclic tetrapeptides containing two beta-Ala residues.

Science.gov (United States)

Vass, Elemér; Majer, Zsuzsa; Kohalmy, Krisztina; Hollósi, Miklós

2010-08-01

The optical spectroscopic characterization of gamma-turns in solution is uncertain and their distinction from beta-turns is often difficult. This work reports systematic ECD and vibrational circular dichroism (VCD) spectroscopic studies on gamma-turn model cyclic tetrapeptides cyclo(Ala-beta-Ala-Pro-beta-Ala) (1), cyclo(Pro-beta-Ala-Pro-beta-Ala) (2) and cyclo(Ala-beta-Ala-Ala-beta-Ala) (3). Conformational analysis performed at the 6-31G(d)/B3LYP level of theory using an adequate PCM solvent model predicted one predominant conformer for 1-3, featuring two inverse gamma-turns. The ECD spectra in ACN of 1 and 2 are characterized by a negative n-->pi* band near 230 nm and a positive pi-->pi* band below 200 nm with a long wavelength shoulder. The ECD spectra in TFE of 1-3 show similar spectra with blue-shifted bands. The VCD spectra in ACN-d(3) of 1 and 2 show a +/-/+/- amide I sign pattern resulting from four uncoupled vibrations in the case of 1 and a sequence of two positive couplets in the case of 2. A -/+/+/- amide I VCD pattern was measured for 3 in TFE-d(2). All three peptides give a positive couplet or couplet-like feature (+/-) in the amide II region. VCD spectroscopy, in agreement with theoretical calculations revealed that low frequency amide I vibrations (at approximately 1630 cm(-1) or below) are indicative of a C(7) H-bonded inverse gamma-turns with Pro in position 2, while gamma-turns encompassing Ala absorb at higher frequency (above 1645 cm(-1)). Copyright 2010 Wiley-Liss, Inc.

Study of multi-neutron emission in the $\\beta$-decay of $^{11}$Li

CERN Multimedia

A new investigation of neutron emission in the $\\beta$-decay of $^{11}$Li is proposed. The principal goal of this study will be to directly measure, for the first time for any system, two $\\beta$-delayed neutrons in coincidence and determine the energy and angular correlations. This will be possible using liquid scintillator detectors, capable of distinguishing between neutrons and ambient $\\gamma$ and cosmic-rays, coupled to a new digital electronics and acquisition system. In parallel, a considerably more refined picture of the single-neutron emission will be obtained.

Using Compton scattering for random coincidence rejection

International Nuclear Information System (INIS)

Kolstein, M.; Chmeissani, M.

2016-01-01

The Voxel Imaging PET (VIP) project presents a new approach for the design of nuclear medicine imaging devices by using highly segmented pixel CdTe sensors. CdTe detectors can achieve an energy resolution of ≈ 1% FWHM at 511 keV and can be easily segmented into submillimeter sized voxels for optimal spatial resolution. These features help in rejecting a large part of the scattered events from the PET coincidence sample in order to obtain high quality images. Another contribution to the background are random events, i.e., hits caused by two independent gammas without a common origin. Given that 60% of 511 keV photons undergo Compton scattering in CdTe (i.e. 84% of all coincidence events have at least one Compton scattering gamma), we present a simulation study on the possibility to use the Compton scattering information of at least one of the coincident gammas within the detector to reject random coincidences. The idea uses the fact that if a gamma undergoes Compton scattering in the detector, it will cause two hits in the pixel detectors. The first hit corresponds to the Compton scattering process. The second hit shall correspond to the photoelectric absorption of the remaining energy of the gamma. With the energy deposition of the first hit, one can calculate the Compton scattering angle. By measuring the hit location of the coincident gamma, we can construct the geometric angle, under the assumption that both gammas come from the same origin. Using the difference between the Compton scattering angle and the geometric angle, random events can be rejected.

Studies of. gamma. -ray irradiation effects on tris(. beta. -diketonato)iron(III) and cobalt(III) coordination compounds by means of Moessbauer spectroscopy and magnetic susceptibility measurements

Energy Technology Data Exchange (ETDEWEB)

Sakai, Y.; Endo, K.; Sano, H. (Tokyo Metropolitan Univ. (Japan). Faculty of Science)

1981-06-01

Both absorption Moessbauer spectroscopy and magnetic susceptibility measurements on tris(..beta..-diketonato)iron(III) and cobalt(III) compounds indicate that ligands which have phenyl group as a substituent are more stable to ..gamma..-ray radiolysis, in accordance with previous results of emission Moessbauer spectroscopic studies of /sup 57/Co-labelled tris (..beta..-diketonato)cobalt(III) compounds.

Development of portable Liquid Scintillation counters for on-site primary measurement of radionuclides using the Triple-to-Double Coincidence Ratio method

International Nuclear Information System (INIS)

Cassette, P.; Capogni, M.; De Felice, P.; Johansson, L.; Sephton, J.; Kossert, K.; Naehle, O.

2013-06-01

The Triple-to-Double Coincidence Ratio (TDCR) method in Liquid Scintillation counting (LSC) is a primary radionuclide standardization method widely used in National Metrology laboratories and was primarily developed for the activity measurement of beta emitters. It is based on liquid scintillation: the light is detected by three photomultipliers (PM) and the detection efficiency is evaluated by using a model which uses the ratio of triple-to-double coincidences between the PM tubes. Up to now, most of current TDCR systems were locally-made metrology instruments neither aimed at nor suitable for in-situ measurements. In the framework of the European Metrofission project, a work package was dedicated to the realisation of miniature self-calibrated primary TDCR systems, which are state-of-the-art, for use on-site. The challenge was to develop a versatile portable, table-top designed instrument, from this metrology device. This implied improvements for the miniaturisation of the detection chamber, for the miniaturisation of electronic modules by exploring the possibilities of digital treatment, and for the validation of models and extension of them to nuclides with special beta spectrum shapes, to nuclides with complex decay schemes including many gamma-rays and to nuclides with higher atomic number decaying by electron capture. Four prototypes of counters were built by the Metrofission partners ENEA (Italy), LNHB (France), NPL (UK) and PTB (Germany) using various technical approaches. The paper describes these prototypes and provides some details on the choice of the technical options concerning the design of the optical chamber, of the photodetectors and of the acquisition system. (authors)

Development of a minicomputer system for on-line processing of gamma--gamma coincidence events and measurements of E2/M1 mixing ratios in 110Cd and 134Ba

International Nuclear Information System (INIS)

Ruhter, W.D.

1977-12-01

A megachannel pulse-height analysis system using a 32,000-word PDP-8/E minicomputer and two moving-head disk memories was developed. The system has a storage capacity of 2 18 events at any of 2 20 data locations, is capable of processing 1,040 events/s, and provides on-line sorting and disk storage. An X- or Y- pulse-height spectrum in coincidence with one to four arithmetically combined pulse-height windows can be assembled in core for scope display and spectral analysis within 2 to 20 seconds. The software for the system was written extensively in machine language. Excellent energy and timing resolution were achieved. An energy resolution of 2.3 keV fwhm and a timing resolution of 8.5 ns fwhm were obtained for 60 Co at a singles rate of 10,000 counts/s. The prompt timing peak remained Gaussian down to the fwtm by gating the TAC with SCAs which discriminated against low-energy events. The coincidence electronics also allowed on-line subtraction of accidental coincidence events. Alignment of the detectors and tests of the system's performance were made by measuring solid-angle correction factors for the Ge(Li) detectors through the correlation measurements of the 0 + --2 + --0 + cascade in 106 Pd, and by measuring the angular spread of positron annihilation radiation coincidences. Results were in excellent agreement with theoretical solid-angle correction factors calculated for the detector and source sizes used. Directional correlation data were obtained for gamma-ray cascades in 134 Ba and 110 Cd. Analyses of these data gave E2/M1 mixing ratios which are in excellent agreement with results obtained by other investigators. The improved resolution and data processing capabilities of this system gave new results for the 563-keV transition in 134 Ba and the 1505-keV transition in 110 Cd. E2/M1 mixing ratios of 13.3/sup +2.3/sub -1.8/ for the 563-keV transition and -1.24 +- 0.20 for the 1505-keV transition were measured

Application of a proportional counter to some particular cases of {alpha} measurements; Applications d'un compteur proportionnel a quelques cas particuliers de mesures {alpha}

Energy Technology Data Exchange (ETDEWEB)

Ferret, J; Gasc, M T; Le Du, R [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1965-07-01

I - A measurement method based on {alpha} {gamma} coincidences is used for activity measurements on {sup 241}Am in the presence of a strong {alpha} activity due to Pu. The sensitivity of the apparatus makes it possible to detect: less than 10{sup -7} {mu}C {sup 241}Am in the presence of a Pu activities several hundred times greater. II - The same equipment has been used for {alpha} measurements on {alpha}-emitting sources in the presence of very strong {beta} and {gamma} activities. In particular results are given for {alpha}-activity measurements on powder samples. It is even possible in these conditions, to detect or measure {sup 241}Am. III - The equipment makes possible also: - the absolute calibration of a pure {sup 241}Am source - {sup 237}Np measurements - simultaneous measurements of {alpha}, {beta} and {gamma} activities in solid samples in various forms. IV - The assembly includes a small-size proportional counter operating in conjunction with a {gamma} probe, together with auxiliary electronic equipment (stabilized high voltages, amplifiers, a coincidence unit, a sealer). (authors) [French] I - Une methode de mesures par coincidences {alpha} {gamma} est utilisee pour des mesures d'activite de {sup 241}Am en presence d'activite {alpha} (due au Pu) importante. -La sensibilite de l'appareillage permet de deceler: moins de 10{sup -7} {mu}C {sup 241}Am dans les activites {alpha} Pu plusieurs centaines de fois plus importantes. II - Le meme appareillage a ete utilise pour des mesures {alpha} sur des sources emettrices {alpha} en presence d'activites {beta} et {gamma} tres importantes. En particulier des mesures d'activite {alpha} sur des echantillons de poudre sont exposees. Il est meme possible, dans ces conditions, de deceler ou mesurer {sup 241}Am. III - L'ensemble permet egalement: - l'etalonnage absolu d'une source de {sup 241}Am pur - des mesures de {sup 237}Np - des mesures simultanees d'activites {alpha}, {beta} et {gamma} dans des echantillons solides

Study of octupole deformation in n-rich Ba isotopes populated via $\\beta$-decay

CERN Multimedia

We propose to exploit the unique capability of the ISOLDE facility to produce $^{150, 151, 152}$Cs beams to investigate their radioactive $\\beta$-decay to $^{150, 151, 152}$Ba. The interest to study this mass region is twofold: these nuclei are expected to show octupole deformations already in their low-lying state, secondly information on the $\\beta$-decay is needed for the nuclear astrophysical model. The experiment will be performed with the ISOLDE Decay Station (IDS) setup using the fast tape station of K.U.-Leuven, equipped with four Clover Germanium detectors, four LaBr$_{3}$(Ce) detectors and one LEP HPGe detector. Information on the $\\beta$-decay, such as lifetimes and delayed neutron-emission probabilities, will be extracted, together with the detailed spectroscopy of the daughter nuclei, via $\\gamma$-$\\gamma$-coincidences and lifetime measurement of specific states.

Resting-state beta and gamma activity in Internet addiction.

Science.gov (United States)

Choi, Jung-Seok; Park, Su Mi; Lee, Jaewon; Hwang, Jae Yeon; Jung, Hee Yeon; Choi, Sam-Wook; Kim, Dai Jin; Oh, Sohee; Lee, Jun-Young

2013-09-01

Internet addiction is the inability to control one's use of the Internet and is related to impulsivity. Although a few studies have examined neurophysiological activity as individuals with Internet addiction engage in cognitive processing, no information on spontaneous EEG activity in the eyes-closed resting-state is available. We investigated resting-state EEG activities in beta and gamma bands and examined their relationships with impulsivity among individuals with Internet addiction and healthy controls. Twenty-one drug-naïve patients with Internet addiction (age: 23.33 ± 3.50 years) and 20 age-, sex-, and IQ-matched healthy controls (age: 22.40 ± 2.33 years) were enrolled in this study. Severity of Internet addiction was identified by the total score on Young's Internet Addiction Test. Impulsivity was measured with the Barratt Impulsiveness Scale-11 and a stop-signal task. Resting-state EEG during eyes closed was recorded, and the absolute/relative power of beta and gamma bands was analyzed. The Internet addiction group showed high impulsivity and impaired inhibitory control. The generalized estimating equation showed that the Internet-addiction group showed lower absolute power on the beta band than did the control group (estimate = -3.370, p Internet-addiction group showed higher absolute power on the gamma band than did the control group (estimate = 0.434, p Internet addiction as well as with the extent of impulsivity. The present study suggests that resting-state fast-wave brain activity is related to the impulsivity characterizing Internet addiction. These differences may be neurobiological markers for the pathophysiology of Internet addiction. Copyright © 2013 Elsevier B.V. All rights reserved.

Alpha/beta(gamma ray) discrimination and spillover quantification with a BaF2 scintillator

International Nuclear Information System (INIS)

DeVol, T.A.; Fjeld, R.A.

1994-01-01

A simple pulse shape discrimination technique was used to separate alpha and beta(gamma ray) interactions in a BaF 2 scintillator. The separation was not ideal, resulting in a 5.1% spillover of alpha interactions into the beta(gamma ray) channel and 11.9% spillover of beta(gamma ray) interactions into the alpha channel for a set pulse shape discriminator. The misclassification of events was reduced by post-processing the data using either a simple analytical technique or a more complex linear least squares technique. Both techniques typically reduced the difference between the expected and calculated interaction rates to <10% when the ratio of beta(gamma ray) to alpha count rate was less than 100 : 1. ((orig.))

Y-formalism and curved {beta}-{gamma} systems

Energy Technology Data Exchange (ETDEWEB)

Grassi, Pietro Antonio [DISTA, Universita del Piemonte Orientale, via Bellini 25/g, 15100 Alessandria (Italy); INFN - Sezione di Torino (Italy)], E-mail: antonio.pietro.grassi@cern.ch; Oda, Ichiro [Department of Physics, Faculty of Science, University of the Ryukyus, Nishihara, Okinawa 903-0213 (Japan); Tonin, Mario [Dipartimento di Fisica, Universita degli Studi di Padova, INFN, Sezionedi Padova, Via F. Marzolo 8, 35131 Padova (Italy)

2009-01-01

We adopt the Y-formalism to study {beta}-{gamma} systems on hypersurfaces. We compute the operator product expansions of gauge-invariant currents and we discuss some applications of the Y-formalism to model on Calabi-Yau spaces.

ESCL8R and LEVIT8R: interactive graphical analysis of {gamma}-{gamma} and {gamma}-{gamma}-{gamma} coincidence data for level schemes

Energy Technology Data Exchange (ETDEWEB)

Radford, D C [Atomic Energy of Canada Ltd., Chalk River, ON (Canada). Chalk River Nuclear Labs.

1992-08-01

The extraction of complete and consistent nuclear level schemes from high-fold coincidence data will require intelligent computer programs. These will need to present the relevant data in an easily assimilated manner, keep track of all {gamma}-ray assignments and expected coincidence intensities, and quickly find significant discrepancies between a proposed level scheme and the data. Some steps in this direction have been made at Chalk River. The programs ESCL8R and LEVIT8R, for analysis of two-fold and three-fold data sets respectively, allow fast and easy inspection of the data, and compare the results to expectations calculations on the basis of a proposed level scheme. Least-squares fits directly to the 2D and/or 3D data, with the intensities and energies of the level scheme transitions as parameters, allow fast and easy extraction of the optimum physics results. (author). 4 refs., 3 figs.

Particle-gamma coincidence measurements in 12C+12C and 12C+Pb collisions at 2.1 GeV/nucleon incident energy

International Nuclear Information System (INIS)

Roche, G.; Koontz, R.; Mulera, T.; Pugh, H.G.; Schroeder, L.S.; Hallman, T.; Madansky, L.; Carroll, J.; Chang, C.C.; Kirk, P.N.; Krebs, G.; Vicente, J.

1985-01-01

A particle-gamma coincidence experiment has been performed with a 2.1 GeV per nucleon 12 C beam from the Bevalac. Data were taken with C and Pb targets. The γ-ray spectra are almost independent of the energy or the kind of charged particles detected in coincidence, mainly protons and deuterons. These γ-ray spectra are interpreted as resulting from π 0 decay, and are consistent with known π 0 production rates. A search for a possible decay of singly-charged anomalons into a gamma and a deuteron (or unbound proton-neutron system) has been done by studying the γp and γd invariant mass distributions. The upper limits for such a process are found to be 2 to 20% of the deuteron production rate, for anomalon masses for 200 to 400 MeV above the deuteron mass, with an anomalon mean lifetime of up to 10 -9 s, depending on which kind of decay process is considered. (orig.)

The determination of electron momentum densities by inelastic scattering gamma-ray-electron coincidence measurements: The (γ,eγ)-experiment

International Nuclear Information System (INIS)

Rollason, A.J.; Bell, F.; Schneider, J.R.

1989-09-01

Measurements have been made of the recoiling electron in 320 keV gamma ray inelastic scattering collisions in thin aluminium targets. The angular correlation of these electrons detected in coincidence with the scattered photon is in agreement with the kinematic requirements of the Compton effect and is correctly predicted by Monte Carlo simulations based on the impulse approximation. Further simulations of ideal-geometry experiments indicate that information about the initial electron momenta is available from an examination of those electron-photon events originating in a surface layer of one electronic mean free path depth and that elastic scattering of the recoil electrons from greater depths produces a nearly flat background to this signal. The results clearly demonstrate the feasibility of the (γ,eγ) experiment for studying electron momentum densities with synchrotron radiation. (orig.) With 23 refs., 17 figs

Measuring 226Ra and 232Th activity in soil and vegetation samples using a method of double γ-coincidences

International Nuclear Information System (INIS)

Antovic, N.M.; Antovic, I.

2010-01-01

A coincidence method for measuring radium and thorium activity has been developed using the PRIPYAT-2M gamma-ray coincidence spectrometer, with six NaI(Tl) detectors and registration geometry close to 4π. It was tested by measuring soil samples from the Northern region of Montenegro, as well as vegetation samples from the same region. The results showed a good agreement with ones obtained by the HPGe spectrometer. (author)

Support vector machines for prediction and analysis of beta and gamma-turns in proteins.

Science.gov (United States)

Pham, Tho Hoan; Satou, Kenji; Ho, Tu Bao

2005-04-01

Tight turns have long been recognized as one of the three important features of proteins, together with alpha-helix and beta-sheet. Tight turns play an important role in globular proteins from both the structural and functional points of view. More than 90% tight turns are beta-turns and most of the rest are gamma-turns. Analysis and prediction of beta-turns and gamma-turns is very useful for design of new molecules such as drugs, pesticides, and antigens. In this paper we investigated two aspects of applying support vector machine (SVM), a promising machine learning method for bioinformatics, to prediction and analysis of beta-turns and gamma-turns. First, we developed two SVM-based methods, called BTSVM and GTSVM, which predict beta-turns and gamma-turns in a protein from its sequence. When compared with other methods, BTSVM has a superior performance and GTSVM is competitive. Second, we used SVMs with a linear kernel to estimate the support of amino acids for the formation of beta-turns and gamma-turns depending on their position in a protein. Our analysis results are more comprehensive and easier to use than the previous results in designing turns in proteins.

New detection modules for gamma, beta and X-ray cameras

International Nuclear Information System (INIS)

Azman, S.; Bolle, E.; Dang, K.Q.; Dang, W.; Dietzel, K.I.; Froberg, T.; Gaarder, P.E.; Gjaerum, J.A.; Haugen, S.H.; Hellum, G.; Henriksen, J.R.; Johanson, T.M.; Kobbevik, A.; Maehlum, G.; Meier, D.; Mikkelsen, S.; Ninive, I.; Oya, P.; Pavlov, N.; Pettersen, D.M.; Sundal, B.M.; Talebi, J.; Yoshioka, K.

2003-01-01

Full text: Ideas ASA is developing new detection modules for gamma, beta and X-ray cameras. Recent developments focus on modules using various semi-conductor materials (CZT, HgI, Si). The development includes ASIC design, detector module development, and implementation in camera heads. In this presentation we describe the characteristics of important ASICs and its properties in terms of electronic noise, and the modes for measuring signals (switched current modes, sparsified modes, self triggered modes). The ASICs are specific for detectors and applications. We describe recent developments using various semi - conductor materials. We describe important design aspects for medical applications and in life science (SPECT, beta, X-ray cameras)

Standardization of Ga-68 by coincidence measurements, liquid scintillation counting and 4πγ counting

International Nuclear Information System (INIS)

Roteta, Miguel; Peyres, Virginia; Rodríguez Barquero, Leonor; García-Toraño, Eduardo; Arenillas, Pablo; Balpardo, Christian; Rodrígues, Darío; Llovera, Roberto

2012-01-01

The radionuclide 68 Ga is one of the few positron emitters that can be prepared in-house without the use of a cyclotron. It disintegrates to the ground state of 68 Zn partially by positron emission (89.1%) with a maximum energy of 1899.1 keV, and partially by electron capture (10.9%). This nuclide has been standardized in the frame of a cooperation project between the Radionuclide Metrology laboratories from CIEMAT (Spain) and CNEA (Argentina). Measurements involved several techniques: 4πβ−γ coincidences, integral gamma counting and Liquid Scintillation Counting using the triple to double coincidence ratio and the CIEMAT/NIST methods. Given the short half-life of the radionuclide assayed, a direct comparison between results from both laboratories was excluded and a comparison of experimental efficiencies of similar NaI detectors was used instead. - Highlights: ► We standardized the positron emitter Ga-68 in a bilateral cooperation. ► We used several techniques, as coincidence, integral gamma and liquid scintillation. ► An efficiency comparison replaced a direct comparison of reference materials.

Determination of beta and gamma radioactivity on the coal

International Nuclear Information System (INIS)

Suhardi; Mulyono; Sutanto WW; Rosidi

2013-01-01

Radioactivity in coal, botton ash and fly ash. This determination was carried out to know each the radioactivity of β gross, γ gross on the coal, botton ash and fly ash, which accommodation of environment data the present in PLTU Paiton Probolinggo. Samples taken preparation and analysis based on the procedures of environmental radioactivity analysis. The radioactivity on the PLTU Paiton Probolinggo detected by beta gross Spectrometer with Geiger Muller (GM) and gamma Spectrometer with Ge(Li) detector. The result indicates that radioactivity concentration of beta and gamma gross are (95,57-308,26) Bq/kg and (1,374 - 31,677) Bq/kg respectively. (author)

Determining chance coincidence, survival factor and decay factor in 220Rn delayed coincidence measurement

International Nuclear Information System (INIS)

Huang Derong; Yan Yongjun; Zhou Jianliang; Qiu Shoukang

2013-01-01

The method and calculation formulas to determine the chance coincidence in the 220 Rn coincidence measurement are introduced in this paper. The poisson distribution is introduced to correct the chance coincidence. The relative deviation of the true coincidence between the method and the Giffin's is within 5% after the correction of the cohance coincidence. The measurement of 220 Rn is done by comparative measurement with RAD7. The results shows that 220 Rn can be measured by the method with a relative deviation of 14%. Mean while, for the 220 Rn flow regime is difficult to meet the condition of calculation formulas, a solution to solve the survival factor and decay factor is proposed and the error come from the useage of theoretical calculation formula is avoided. (authors)

Coincidence measurements with the use of detectors measuring the energy of the radiances (proportional meters and scintillation counter); Mesures de coincidences avec utilisation de detecteurs mesurant l'energie des rayonnements (compteurs proportionnels et compteur a scintillations)

Energy Technology Data Exchange (ETDEWEB)

Sartory, M [Commissariat a l' Energie Atomique, Saclay(France). Centre d' Etudes Nucleaires

1953-07-01

In the setting of the realization of a set of installations permitting of the measures of coincidences between sorted radiances according to their energies, an installation understanding a proportional counter and a scintillation counter has been constructed and optimized. It has been used to do some measures of coincidences between X{sub K} photons and photons {gamma} issued at the time of the radioactive transformation of the selenium 75 (electronic capture). The efficiency of the proportional meter has been determined roughly. Besides, a proportional counter of solid angle neighboring of 4{pi} was able to achieve measures of coincidences while only doing one selection of amplitudes: indeed, the simultaneity of the detection of two radiances appear by an impulse whose amplitude is the sum of the amplitudes of the impulses resulting from each of the studied radiations. This method, applied to the coincidences between X-rays, permitted to bring the information on the diagram of decay of the arsenic 73. Besides, the coefficient of internal conversion of a consecutive transition to this decay has been valued. (author) [French] Dans le cadre de la realisation d'une serie de montages permettant des mesures de coincidences entre rayonnements tries d'apres leurs energies, un montage comprenant un compteur proportionnel et un compteur a scintillations a ete construit et mis au point. Il a ete utilise pour effectuer quelques mesures de coincidences entre photons X{sub K} et photons {gamma} emis lors de la transformation radioactive du selenium 75 (capture electronique). L'efficacite du compteur proportionnel a ete approximativement determinee. De plus, un compteur proportionnel d'angle solide voisin de 4{pi} a pu etre utilise pour realiser des mesures de coincidences en n'effectuant qu'une selection d'amplitudes: en effet, la simultaneite de la detection de deux rayonnements se manifeste par une impulsion dont l'amplitude est la somme des amplitudes des impulsions

Gamma-spectrometric and total alpha-beta counting methods for radioactivity analysis of deuterium depleted water

International Nuclear Information System (INIS)

Ferdes, Ov. S.; Mladin, C.; Vladu, Mihaela; Bulubasa, G.; Bidica, N.

2008-01-01

According to national regulations, as well as to the EU directive on the quality of drinking water, the radionuclide concentrations represent some of the drinking water quality parameters. Among the most important radioactivity content parameters are: the total alpha and total beta concentration (Bq/l); K-40 content, and the gamma-nuclides volume activities. The paper presents the measuring methods for low-level total alpha and/or beta counting of volume samples, as well as the high-resolution gamma-ray spectrometric method used to measure the volume activity of nuclides in drinking water. These methods are applied to monitor the radioactivity content and quality of the QLARIVIA brand of Deuterium depleted water (DDW). There are discussed the performances of these applied methods as well as some preliminary results. (authors)

Microcalorimetric and spectrographic studies on host-guest interactions of {alpha}-, {beta}-, {gamma}- and M{beta}-cyclodextrin with resveratrol

Energy Technology Data Exchange (ETDEWEB)

Li, Hui; Xu, Xiangyu; Liu, Min [College of Chemistry and Chemical Engineering, Liaocheng University, Liaocheng 252059, Shandong Province (China); Sun, Dezhi, E-mail: sundezhisdz@163.com [College of Chemistry and Chemical Engineering, Liaocheng University, Liaocheng 252059, Shandong Province (China); Li, Linwei, E-mail: lilinwei@lcu.edu.cn [College of Chemistry and Chemical Engineering, Liaocheng University, Liaocheng 252059, Shandong Province (China)

2010-10-20

Thermal effects of inclusion processes of {alpha}-, {beta}-, {gamma}- and M{beta}-cyclodextrin with resveratrol (RES) in aqueous solutions were determined by isothermal titration calorimetry (ITC) with nanowatt sensitivity at the temperature of 298.15 K. Standard enthalpy changes, stoichiometry and equilibrium constants of the inclusion complexes were derived from the direct calorimetric data utilizing nonlinear simulation. The thermodynamic parameters were discussed in the light of weak interactions between the host and the guest molecules combining with UV spectral message. The results indicate that all of the complexes formed in the aqueous solutions are in 1:1 stoichiometry. The binding processes of {alpha}-, {beta}- and M{beta}-cyclodextrin with the guest are mainly driven by enthalpy, while that of {gamma}-cyclodextrin with the drug is driven by both enthalpy and entropy.

Linear polarization measurements at H. beta. of early-type emission line stars

Energy Technology Data Exchange (ETDEWEB)

Clarke, D; McLean, I S [Glasgow Univ. (UK)

1976-02-01

Linear polarization measurements across the H..beta.. emission lines of the stars ..gamma.. Cas, zeta Tau and 48 Per are presented. For the first two stars there is a marked reduction of the polarization at the centre of the line and for ..gamma.. Cas, this varies from night to night. During the H..beta.. observations of zeta Tau, a change of polarization over tens of minutes was indicated in a monitor channel tuned to the continuum on the blue side of H..beta... For the fainter star, 48 Per, the uncertainties of the polarimetry were increased in relation to ..gamma.. Cas and zeta Tau by a factor of about two and at this precision, no differential effects across the line were recorded. Observations of ..cap alpha.. Cyg are also given to demonstrate the reliability of the polarimeter.

Experimentation with a prototype incinerator for beta-gamma waste

International Nuclear Information System (INIS)

Farber, M.G.; Lewandowski, K.E.; Becker, G.W.

1982-01-01

A test facility for the incineration of suspect and low-level beta-gamma waste has been built and operated at the Savannah River Laboratory. The processing steps include waste feeding, incineration, ash residue packaging, and off-gas cleanup. Demonstration of the full-scale (180 kg/hr) facility with nonradioactive, simulated waste is currently in progress. At the present time, over nine metric tons of material including rubber, polyethylene, and cellulose have been incinerated during three burning campaigns. A comprehensive test program of solid and liquid waste incineration is being implemented. The data from the research program is providing the technical basis for a phase of testing with low-level beta-gamma waste generated at the Savannah River Plant

Coincidence method for determination of radionuclides activities

International Nuclear Information System (INIS)

Andrukhovich, S.K.; Berestov, A.V.; Rudak, E.A.

2004-01-01

The radon and radium activity measurements using six-crystal gamma-gamma coincidence, 4 -spectrometer PRIPJAT and radioactivity measurements in different samples of meat and vegetation by 32-crystal spectrometer ARGUS, are described. Radiation detector with 4 -geometry provides higher efficiency, and therefore shorter counting time than a detector without such geometry. However, its application is limited by the fact that obtained spectrum contains summing peaks of all γ-quanta registered in coincidence. Multiparameter information on coincident photon emission can be obtained only by a detection system where the 4 -geometry is made by many detectors, such are both the PRIPJAT and the ARGUS - γ-coincidence spectrometer of the Crystal Ball type in the Institute of Physics, Minsk [1,2]. There are other characteristics, as background conditions, energy and time resolution, makes it ve suitable for investigation of rare decays and interactions, cascade transitions, k intensity radiations etc. We are developing a method of 2 26R a and 2 26 Rn measurement by a multidetector 4 -spectrometer. The method is based on coincidence counting of γ-rays from two step cascade transitions that follow - decay of 2 14 Bi. Its application to the PRIPL spectrometer, which has 6 Nal(Tl) detectors, is presented here, as well as the method of the determination of radionuclide activities based on the registration of the cascades intensity of γ-rays of different multiplicity using ARGUS

Beta, but not gamma, band oscillations index visual form-motion integration.

Directory of Open Access Journals (Sweden)

Charles Aissani

Full Text Available Electrophysiological oscillations in different frequency bands co-occur with perceptual, motor and cognitive processes but their function and respective contributions to these processes need further investigations. Here, we recorded MEG signals and seek for percept related modulations of alpha, beta and gamma band activity during a perceptual form/motion integration task. Participants reported their bound or unbound perception of ambiguously moving displays that could either be seen as a whole square-like shape moving along a Lissajou's figure (bound percept or as pairs of bars oscillating independently along cardinal axes (unbound percept. We found that beta (15-25 Hz, but not gamma (55-85 Hz oscillations, index perceptual states at the individual and group level. The gamma band activity found in the occipital lobe, although significantly higher during visual stimulation than during base line, is similar in all perceptual states. Similarly, decreased alpha activity during visual stimulation is not different for the different percepts. Trial-by-trial classification of perceptual reports based on beta band oscillations was significant in most observers, further supporting the view that modulation of beta power reliably index perceptual integration of form/motion stimuli, even at the individual level.

Development of the software dead time methodology for the 4πβ-γ software coincidence system analysis program

International Nuclear Information System (INIS)

Toledo, Fabio de; Brancaccio, Franco; Dias, Mauro da Silva

2009-01-01

The Laboratorio de Metrologia Nuclear - LMN, Nuclear Metrology Laboratory -, at IPEN-CNEN/SP, Sao Paulo, Brazil, developed a new Software Coincidence System (SCS) for 4πβ-γ radioisotope standardization. SCS is composed by the data acquisition hardware, for the coincidence data recording, and the coincidence data analysis program that performs the radioactive activity calculation for the target sample. Due to hardware intrinsic signal sampling characteristics, multiple undesired data recording occurs from a single saturated pulse. Also pulse pileup leads to bad data recording. As the beta counting rates are much greater than the gamma ones, due to the high 4π geometry beta detecting efficiencies, the beta counting significantly increases because of multiple pulse recordings, resulting in a respective increasing in the calculated activity value. In order to minimize such bad recordings effect, a software dead time value was introduced in the coincidence analysis program, under development at LMN, discarding multiple recordings, due to pulse pileup or saturation. This work presents the methodology developed to determine the optimal software dead time data value, for better accuracy results attaining, and discusses the results, pointing to software improvement possibilities. (author)

Determination iodine in biological materials using instrumental neutron activation and anti-coincidence gamma-ray spectrometry

International Nuclear Information System (INIS)

Zhang, W.H.; Chatt, A.

1997-01-01

Iodine is an element of interest in nutritional research. Its lower limit of safe and adequate daily dietary intake for adults varies between 150 and 200 micrograms per day. In the present study, an epithermal instrumental neutron activation analysis (EINAA) method in conjunction with anti-coincidence counting has been developed for the determination of ppb levels of iodine in individual food items. Typically 200-300 mg of a sample are irradiated for 10 or 20 minutes at the Dalhousie University SLOWPOKE-2 reactor in an epithermal flux of 1x10 11 n cm -2 s -1 , followed by 1 min decay and then counting for 30 min. The 443-keV gamma-ray of 128 I is used for measuring iodine content by anti-coincidence counting. The anti-coincidence spectrometer consists of a 25% HPGe detector surrounded by a 10''x10'' NaI(TI) annulus and a 3''x3'' NaI(TI) plug. This system has a peak-to-Compton ratio of about 650 to 1 for the 661.6-keV photopeak of 137 Cs. The Compton background resulting from the scattering of many gamma-rays of energies higher than 443 keV can be reduced by a factor of about 4 using anti-coincidence counting compared to conventional counting. The detection limit for iodine can be improved by a factor of 2 to 5 depending on the sample matrix, dead time, position of the annulus and counting geometry among several other factors.The lowest detection limit of 5 ppb can be achieved for low-salt foods. This limit is comparable to that obtained by a preconcentration NAA (PNAA) method. However, a detection limit of 20 ppb is more realistic for samples containing high amounts of Na, Cl and Al. The results obtained for many reference materials are in good agreement with the certified values and those reported by the PNAA method. Details of the methods and results will be reported

Determination iodine in biological materials using instrumental neutron activation and anti-coincidence gamma-ray spectrometry

Energy Technology Data Exchange (ETDEWEB)

Zhang, W.H.; Chatt, A. [Dalhousie University, Halifax, Nova Scotia (Canada). Radiochemistry Research Laboratory

1997-10-01

Iodine is an element of interest in nutritional research. Its lower limit of safe and adequate daily dietary intake for adults varies between 150 and 200 micrograms per day. In the present study, an epithermal instrumental neutron activation analysis (EINAA) method in conjunction with anti-coincidence counting has been developed for the determination of ppb levels of iodine in individual food items. Typically 200-300 mg of a sample are irradiated for 10 or 20 minutes at the Dalhousie University SLOWPOKE-2 reactor in an epithermal flux of 1x10{sup 11} n cm{sup -2} s{sup -1}, followed by 1 min decay and then counting for 30 min. The 443-keV gamma-ray of {sup 128}I is used for measuring iodine content by anti-coincidence counting. The anti-coincidence spectrometer consists of a 25% HPGe detector surrounded by a 10``x10`` NaI(TI) annulus and a 3``x3`` NaI(TI) plug. This system has a peak-to-Compton ratio of about 650 to 1 for the 661.6-keV photopeak of {sup 137}Cs. The Compton background resulting from the scattering of many gamma-rays of energies higher than 443 keV can be reduced by a factor of about 4 using anti-coincidence counting compared to conventional counting. The detection limit for iodine can be improved by a factor of 2 to 5 depending on the sample matrix, dead time, position of the annulus and counting geometry among several other factors.The lowest detection limit of 5 ppb can be achieved for low-salt foods. This limit is comparable to that obtained by a preconcentration NAA (PNAA) method. However, a detection limit of 20 ppb is more realistic for samples containing high amounts of Na, Cl and Al. The results obtained for many reference materials are in good agreement with the certified values and those reported by the PNAA method. Details of the methods and results will be reported 6 refs., 2 tabs.

$\\beta$-delayed neutrons from oriented $^{137,139}$I and $^{87,89}$Br nuclei

CERN Multimedia

We propose a world-first measurement of the angular distribution of $\\beta$‐delayed n and $\\gamma$-radiation from oriented $^{137, 139}$I and $^{87,89}$Br nuclei, polarised at low temperature at the NICOLE facility. $\\beta$­-delayed neutron emission is an increasingly important decay mechanism as the drip line is approached and its detailed understanding is essential to phenomena as fundamental as the r‐process and practical as the safe operation of nuclear power reactors. The experiments offer sensitive tests of theoretical input concerning the allowed and first­‐forbidden $\\beta$‐decay strength, the spin-density of neutron emitting states and the partial wave barrier penetration as a function of nuclear deformation. In $^{137}$I and $^{87}$Br the decay feeds predominantly the ground state of the daughters $^{136}$Xe and $^{86}$Kr whereas in $^{139}$I and $^{89}$Br we will explore the use of n-$\\gamma$- coincidence to study neutron transitions to the first and second excited states in the daughters...

Chapter 4: Measurements of total beta-activity in the fallout

International Nuclear Information System (INIS)

Duggleby, J.C.; Johannessen, J.C.; Kotler, L.H.; Stewart, F.M.

1974-01-01

In order to provide information on fresh fission products in fallout reaching Australia from nuclear tests being conducted by France in Polynesia, measurements were made of total beta activity in daily fallout deposition of 25 Australian sampling stations covering a three month period from 25 July to 23 October 1973. The methods employed to measure the radioactivity of the samples are described and the data on total beta-activity, and the calculated external gamma radiation doses from fresh fallout are presented. (R.L.)

Effect of water on self-assembled tubules in {beta}-sitosterol + {gamma}-oryzanol-based organogels

Energy Technology Data Exchange (ETDEWEB)

Adel, Ruud den; Heussen, Patricia C M; Bot, Arjen, E-mail: ruud-den.adel@unilever.co [Unilever Research and Development Vlaardingen, Olivier van Noortlaan 120, NL-3133 AT Vlaardingen (Netherlands)

2010-10-01

Mixtures of {beta}-sitosterol and {gamma}-oryzanol form a network in triglyceride oil that may serve as an alternative to the network of small crystallites of triglycerides occurring in regular oil structuring. The present x-ray diffraction study investigates the relation between the crystal forms of the individual compounds and the mixture in oil, water and emulsion. {beta}-Sitosterol and {gamma}-oryzanol form normal crystals in oil, in water, or in emulsions. The crystals are sensitive to the presence of water. The mixture of {beta}-sitosterol + {gamma}-oryzanol forms crystals in water and emulsions that can be traced back to the crystals of the pure compounds. Only in oil, a completely different structure emerges in the mixture of {beta}-sitosterol + {gamma}-oryzanol, which bears no relation to the structures that are formed by both individual compounds, and which can be identified as a self-assembled tubule (diameter 7.2{+-}0.1 nm, wall thickness 0.8{+-}0.2 nm).

Effect of beta and gamma neurofeedback on memory and intelligence in the elderly.

Science.gov (United States)

Staufenbiel, S M; Brouwer, A-M; Keizer, A W; van Wouwe, N C

2014-01-01

Recent research showed a correlation between cognitive decline and a decrease of EEG gamma activity. In the present double-blind randomized control study, we investigated whether gamma and beta neurofeedback protocols, that have been shown to modulate performance on cognitive control and memory in young adults, also leads to increased brain activity and cognitive performance in elderly. Twenty older adults either performed eight 30-min gamma neurofeedback session or beta neurofeedback session within a period of 21 days. Cognitive performance was determined before and after the training through an IQ and memory task and we added a subjective well-being questionnaire. Both neurofeedback training protocols resulted in a significant increase of the brain activity within each training session, suggesting that the aging brain is still trainable. However, we found no effects on cognitive performance or transfer of the feedback beyond the trainings. We discuss several possible reasons for the lack of training on rest measurements and cognition and ways to improve the feedback protocols for future studies. Copyright © 2013 Elsevier B.V. All rights reserved.

Response-surface models for deterministic effects of localized irradiation of the skin by discrete {beta}/{gamma} -emitting sources

Energy Technology Data Exchange (ETDEWEB)

Scott, B.R.

1995-12-01

Individuals who work at nuclear reactor facilities can be at risk for deterministic effects in the skin from exposure to discrete {Beta}- and {gamma}-emitting ({Beta}{gamma}E) sources (e.g., {Beta}{gamma}E hot particles) on the skin or clothing. Deterministic effects are non-cancer effects that have a threshold and increase in severity as dose increases (e.g., ulcer in skin). Hot {Beta}{gamma}E particles are {sup 60}Co- or nuclear fuel-derived particles with diameters > 10 {mu}m and < 3 mm and contain at least 3.7 kBq (0.1 {mu}Ci) of radioactivity. For such {Beta}{gamma}E sources on the skin, it is the beta component of the dose that is most important. To develop exposure limitation systems that adequately control exposure of workers to discrete {Beta}{gamma}E sources, models are needed for systems that adequately control exposure of workers to discrete {Beta}{gamma}E sources, models are needed for evaluating the risk of deterministic effects of localized {Beta} irradiation of the skin. The purpose of this study was to develop dose-rate and irradiated-area dependent, response-surface models for evaluating risks of significant deterministic effects of localized irradiation of the skin by discrete {Beta}{gamma}E sources and to use modeling results to recommend approaches to limiting occupational exposure to such sources. The significance of the research results as follows: (1) response-surface models are now available for evaluating the risk of specific deterministic effects of localized irradiation of the skin; (2) modeling results have been used to recommend approaches to limiting occupational exposure of workers to {Beta} radiation from {Beta}{gamma}E sources on the skin or on clothing; and (3) the generic irradiated-volume, weighting-factor approach to limiting exposure can be applied to other organs including the eye, the ear, and organs of the respiratory or gastrointestinal tract and can be used for both deterministic and stochastic effects.

Automatic classification of gammas-gamma coincidence matrices

International Nuclear Information System (INIS)

Los Arcos Merino, J. M.; Gonzalez, J. A.

1978-01-01

The information obtained during a coincidence experiment, recorded on magnetic tape by a MULTI-8 minicomputer, is transferred to a new tape in 36 bit words, using the program LEC0M8. The classification in two dimensional matrix form is carried out off-line, on a magnetic disk file, by the program CLAFI. On finishing classification one obtains a copy of the coincidence matrix on the second magnetic tape. Both programs are written to be processed in that order with the UNIVAC 1106 computer of J.E.N. (Author) 4 refs

Automatic classification of gamma-gamma coincidence matrices

International Nuclear Information System (INIS)

Los Arcos Merino, J.M.; Gonzalez Gonzalez, J.A.

1978-01-01

The information obtained during a coincidence experiment, recorded on magnetic tape by a Multi-8 minicomputer, is transferred to a new tape in 36 bit words, using the program Lecom8. The classification in two dimensional matrix form is carried out off-line, on a magnetic disk file, by the program Clafi. On finishing classification one obtains a copy of the coincidence matrix on the second magnetic tape. Both programs are written to be processed in that order with the Univac 1106 computer of J.E.N. (author)

Application of Monte Carlo method in study of the padronization for radionuclides with complex disintegration scheme in 4πβ-γ coincidence System

International Nuclear Information System (INIS)

Takeda, Mauro Noriaki

2006-01-01

The present work described a new methodology for modelling the behaviour of the activity in a 4πβ-γ coincidence system. The detection efficiency for electrons in the proportional counter and gamma radiation in the NaI(Tl) detector was calculated using the Monte Carlo program MCNP4C. Another Monte Carlo code was developed which follows the path in the disintegration scheme from the initial state of the precursor radionuclide, until the ground state of the daughter nucleus. Every step of the disintegration scheme is sorted by random numbers taking into account the probabilities of all β - branches, electronic capture branches, transitions probabilities and internal conversion coefficients. Once the final state was reached beta, electronic capture events and gamma transitions are accounted for the three spectra: beta, gamma and coincidence variation in the beta efficiency was performed simulating energy cut off or use of absorbers (Collodion). The selected radionuclides for simulation were: 134 Cs, 72 Ga which disintegrate by β - transition, 133 Ba which disintegrates by electronic capture and 35 S which is a beta pure emitter. For the latter, the Efficiency Tracing technique was simulated. The extrapolation curves obtained by Monte Carlo were filled by the Least Square Method with the experimental points and the results were compared to the Linear Extrapolation method. (author)

Numerical expressions for the computation of coincidence-summing correction factors in gamma-ray spectrometry with HPGe detectors

International Nuclear Information System (INIS)

Rizzo, S.; Tomarchio, E.

2008-01-01

Full text: The analytical relations used to compute the coincidence-summing effects on spectral response of Ge semiconductor detectors are quite complex and involve full-energy peak and total efficiencies. For point-sources, a general method for calculating the correction factors for gamma ray coincidences has been formulated by Andreev et al. and used by Schima and Hoppes to obtain γ-X K coincidence correction expressions for 17 nuclides. However, because the higher-order terms are neglected, the expressions supplied do not give reliable results in the case of short sample-detector distances. Using the formulae given by Morel et al.[3] and Lepy et al.[4], we have developed a computer program able to get numerical expressions to compute γ-γ e γ-X K coincidence summing corrections for point sources. Only full-energy peak and total efficiencies are needed. Alternatively, values of peak-to-total ratio can be introduced. For extended sources, the same expressions can be always considered with the introduction of 'effective efficiencies' as defined by Arnold and Sima, i.e. an average over the source volume of the spatial distribution of the elementary photon source total efficiency, weighted by the corresponding peak efficiency. We have considered the most used calibration radioisotopes as well as fission products, activation products and environmental isotopes. All decay data were taken from the most recent volumes of 'Table of Radionuclides', CEA Monographie BIPM-5 and a suitable matrix representation of a decay scheme was adopted. For the sake of brevity, we provide for each nuclide a set of expressions for the more intense gamma emissions, considered sufficient for most applications. However, numerical expressions are available for all the stored gamma transitions and can be obtained on request. As examples of the use of the expressions, the evaluation of correction values for point sources and a particulate sample reduced to a 6x6x0.7 cm packet - with reference

{beta}-{gamma} systems and the deformations of the BRST operator

Energy Technology Data Exchange (ETDEWEB)

Zeitlin, Anton M [Department of Mathematics, Yale University, 442 Dunham Lab, 10 Hillhouse Ave, New Haven, CT 06511 (United States)], E-mail: anton.zeitlin@yale.edu

2009-09-04

We describe the relation between simple logarithmic CFTs associated with closed and open strings, and their 'infinite metric' limits, corresponding to the {beta}-{gamma} systems. This relation is studied on the level of the BRST complex: we show that the consideration of metric as a perturbation leads to a certain deformation of the algebraic operations of the Lian-Zuckerman type on the vertex algebra, associated with the {beta}-{gamma} systems. The Maurer-Cartan equations corresponding to this deformed structure in the quasi-classical approximation lead to the nonlinear field equations. As an explicit example, we demonstrate that using this construction, Yang-Mills equations can be derived. This gives rise to a nontrivial relation between the Courant-Dorfman algebroid and homotopy algebras emerging from the gauge theory. We also discuss a possible algebraic approach to the study of beta-functions in sigma-models.

High-$\\gamma$ Beta Beams within the LAGUNA design study

CERN Document Server

Orme, Christopher

2010-01-01

Within the LAGUNA design study, seven candidate sites are being assessed for their feasibility to host a next-generation, very large neutrino observatory. Such a detector will be expected to feature within a future European accelerator neutrino programme (Superbeam or Beta Beam), and hence the distance from CERN is of critical importance. In this article, the focus is a $^{18}$Ne and $^{6}$He Beta Beam sourced at CERN and directed towards a 50 kton Liquid Argon detector located at the LAGUNA sites: Slanic (L=1570 km) and Pyh\\"{a}salmi (L=2300 km). To improve sensitivity to the neutrino mass ordering, these baselines are then combined with a concurrent run with the same flux directed towards a large Water \\v{C}erenkov detector located at Canfranc (L=650 km). This degeneracy breaking combination is shown to provide comparable physics reach to the conservative Magic Baseline Beta Beam proposals. For $^{18}$Ne ions boosted to $\\gamma=570$ and $^{6}$He ions boosted to $\\gamma=350$, the correct mass ordering can be...

PET with a coincidence gamma camera: results in selected oncological questions

International Nuclear Information System (INIS)

Lauer, I.; Haase, A; Adam, S.; Prueter, I.; Richter, E.; Baehre, M.

2001-01-01

Since early 1997, about 1660 investigations with coincidence gamma camera PET (CGC-PET) have been performed in our department, mostly undertaken for oncological questions. Based on these data, several retrospective and prospective studies were performed. In the following, the results in CUP (cancer of unknown primary) syndrome, melanoma and malignant lymphoma are presented. Methods: CGC-PET was performed after application of 250-350 MBq [ 18 F]FDG using a coincidence double head gamma camera with 19 mm Nal cristal. CUP-Syndrome: After completing conventional diagnostic procedures, 32 patients have been examined in a prospective study, including 25 patients with recently detected CUP and 7 patients undergoing restaging after therapy. Localization of the primary tumor was successful in 12 (38%) cases. Melanoma: We evaluated 50 studies in 41 patients suffering from melanoma, retrospectively. CGC-PET showed a sensitivity of 76%, and a specificity of 94%. In comparison to conventional diagnostic methods, CGC-PET delineated important additional information in 16%. CGC-PET was superior to morphological diagnostic tools in the differentiation between residual scar tissue and active tumor following immunochemotherapy. Malignant lymphoma: 29 CGC-PET in 29 patients were performed for staging of malignant lymphoma, sensitivity was 86% versus 88% for CT. Overall CGC-PET showed additional information to conventional diagnostic methods, but revealed problems in detecting small infiltrations of organs. In restaging malignant melanoma (26 patients, 33 studies), specificity of CGC-PET was superior to conventional diagnostics (92% versus 35%). (orig.) [de

Absolute measurement of the $\\beta\\alpha$ decay of $^{16}$N

CERN Multimedia

We propose to study the $\\beta$-decay of $^{16}$N at ISOLDE with the aim of determining the branching ratio for $\\beta\\alpha$ decay on an absolute scale. There are indications that the previously measured branching ratio is in error by an amount significantly larger than the quoted uncertainty. This limits the precision with which the S-factor of the astrophysically important $^{12}$C($\\alpha, \\gamma)^{16}$O reaction can be determined.

Alpha-beta-gamma spectrometer as an aid in directing decontamination of soils

International Nuclear Information System (INIS)

Berger, C.D.

1981-01-01

This technique permits rapid assessment of alpha-beta-gamma-emitter contamination in soils at sufficiently low concentrations to direct field operations. Of particular importance is its applicability during initial decommissioning and decontamination surveys when characterization of alpha and beta contamination in the presence of a high gamma background is necessary. This system has not yet been made portable for in-situ use, but it is expected that results willbe favorable when operated as a field instrument, resulting in simplified standard decontamination operation

Absolute Measurement of Radioactive Materials at the Physikalisch-Technische Bundesanstalt; Mesure absolue des substances radioactives a l'Institut federal de physique appliquee; Absolyutnoe izmerenie radioaktivnykh veshchestv v fiziko-tekhnicheskom federal'nom institute; Determinacion absoluta de la actividad de sustancias radiactivas en el Instituto Federal de Fisica Aplicada

Energy Technology Data Exchange (ETDEWEB)

Weiss, H M [Physikalisch-Technische Bundesanstalt, Braunschweig (Germany)

1960-06-15

A short report is given about the routine methods of standardization of radionuclides. The measurements are done by 4 {pi} {beta} proportional counters, 4 {pi} {beta}-{gamma} coincidence counting and for secondary standardization of {gamma} emitters by 4 {pi} {gamma} ionization chamber. The equipments used and the procedures of source preparation are described. (author) [French] L'auteur presente un rapport succinct sur les methodes courantes de normalisation des radionuclides. Les mesures sont effectuees au moyen de compteurs proportionnels 4 {pi} {beta}, par voie de comptage par coincidences 4 {pi}{beta}-{gamma} et, en ce qui concerne la normalisation secondaire des emetteurs de rayons {gamma}, au moyen d'une chambre d'ionisation 4 {pi} {gamma}. Le memoire contient une description du materiel utilise et des procedes employes pour la preparation des sources. (author) [Spanish] En la memoria se describen brevemente los metodos corrientes de calibracion de radionuclidos. Las mediciones a que se refiere se han efectuado con contadores proporcionales {beta} 4 {pi}, contadores de coincidencias {beta}-{gamma} 4{pi}l; para la calibracion secundaria de emisores {gamma} se ha utilizado una camara de ionizacion {gamma} 4 {pi}. Se describen los aparatos empleados y los procedimientos de preparacion de las fuentes. (author) [Russian] Privoditsya kratkij doklad po obychnym metodam standartizatsi i radioizotopov. Izmereniya osushchestvlyalis {beta}-proportsional'nym i schetchikami na 4 {pi}, schetchikami {beta}-{gamma} sovpadenij i {gamma}-ioniziruyushche j kameroj na 4 i dlya vtorichnoj standartizatsi i {gamma}-izluchatelej . Privoditsya opisanie, ispol'zuemogo oborudovaniya i protsedura podgotovki istochnika. (author)

Study of radiation detectors response in standard X, gamma and beta radiation standard beams

International Nuclear Information System (INIS)

Nonato, Fernanda Beatrice Conceicao

2010-01-01

The response of 76 Geiger-Mueller detectors, 4 semiconductor detectors and 34 ionization chambers were studied. Many of them were calibrated with gamma radiation beams ( 37 Cs and 60 Co), and some of them were tested in beta radiation ( 90 Sr+ 9' 0Y e 204 Tl) and X radiation (N-60, N-80, N-100, N-150) beams. For all three types of radiation, the calibration factors of the instruments were obtained, and the energy and angular dependences were studied. For beta and gamma radiation, the angular dependence was studied for incident radiation angles of 0 deg and +- 45 deg. The curves of the response of the instruments were obtained over an angle interval of 0 deg to +- 90 deg, for gamma, beta and X radiations. The calibration factors obtained for beta radiation were compared to those obtained for gamma radiation. For gamma radiation, 24 of the 66 tested Geiger-Mueller detectors presented results for the energy dependence according to international recommendation of ISO 4037-2 and 56 were in accordance with the Brazilian ABNT 10011 recommendation. The ionization chambers and semiconductors were in accordance to national and international recommendations. All instruments showed angular dependence less than 40%. For beta radiation, the instruments showed unsatisfactory results for the energy dependence and angular dependence. For X radiation, the ionization chambers presented results for energy dependence according to the national recommendation, and the angular dependence was less than 40%. (author)

Calculation of “LS-curves” for coincidence summing corrections in gamma ray spectrometry

Science.gov (United States)

Vidmar, Tim; Korun, Matjaž

2006-01-01

When coincidence summing correction factors for extended samples are calculated in gamma-ray spectrometry from full-energy-peak and total efficiencies, their variation over the sample volume needs to be considered. In other words, the correction factors cannot be computed as if the sample were a point source. A method developed by Blaauw and Gelsema takes the variation of the efficiencies over the sample volume into account. It introduces the so-called LS-curve in the calibration procedure and only requires the preparation of a single standard for each sample geometry. We propose to replace the standard preparation by calculation and we show that the LS-curves resulting from our method yield coincidence summing correction factors that are consistent with the LS values obtained from experimental data.

Gamma-X-ray coincidence Moessbauer spectroscopic study of the aftereffects in sulfate hydrates

International Nuclear Information System (INIS)

Kobayashi, T.; Makita, T.; Fukumura, K.

1990-01-01

The anomalous charge states formed after the electron capture decay of 57 Co in FeSO 4 .H 2 O and FeSO 4 .7H 2 O are investigated using the conventional Moessbauer emission spectroscopy and a gamma-X ray coincidence method. This method is based on the idea that a Moessbauer spectrum observed with the coincidence technique only when K-X rays are emitted is reflected by isolated events with a reduced influence of the Auger-electron self-irradiation. The formation of the anomalous electronic and structural configuration is attributed to the self-radiolysis of the H 2 O and SO 4 2- ligands in the nearest and the second nearest coordination shells around the decaying atom. (orig.)

Mixing of ground-state rotational and gamma and beta vibrational bands in the region A>=228

Energy Technology Data Exchange (ETDEWEB)

Mittal, R; Sahota, H S [Punjabi Univ., Patiala (India). Dept. of Physics

1983-06-21

The mixing of beta, gamma and ground-state bands has been investigated through the experimental determination of mixing parameters Zsub(..gamma..) and Zsub(..beta gamma..). These Zsub(..gamma..) values have been compared with the theoretical calculations of this parameter from the solutions of time-dependent HFB equations on the adiabatic and nonadiabatic assumptions. The experimental values are in better agreement with the results obtained under the nonadiabatic assumption, valid for small deviations from the spherical symmetry.

Radioelements: their detection and measurement; Les radioelements: detection et mesure

Energy Technology Data Exchange (ETDEWEB)

Grinberg, B [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

1960-07-01

A brief review of the properties of nuclear radiations is followed by a description of the basic techniques used for their detection: autoradiography, methods using the ionisation of gases (ionisation chambers, proportional counters, Geiger-Muller counters), scintillation techniques. The principles of the different methods of measurement are explained, whether they concern the activity or the energy absorbed (dosimetry). This is followed by a description of the basic techniques (4 {pi} counter, defined solid angle, {beta}-{gamma} coincidences). (author) [French] Apres un bref rappel des proprietes des rayonnements nucleaires, on decrit les techniques fondamentales employees pour leur detection: autoradiographie, procedes utilisant l'ionisation des gaz (chambres d'ionisation, compteurs proportionnels, compteurs de Geiger-Muller), technique des scintillations. On expose le principe des differentes methodes de mesure concernant soit l'activite, soit l'energie absorbee (dosimetrie). Les techniques fondamentales (compteur 4 {pi}, angle solide defini, coincidences {beta}-{gamma}) sont ensuite decrites. (auteur)

Gamma-ray multiplicity measurements in the 28Si + 64Ni reaction at 163.8 MeV

International Nuclear Information System (INIS)

Di Pietro, A.; Cardella, G.; Musumarra, A.; Papa, M.; Pappalardo, G.; Rizzo, F.; De Rosa, A.; D'Onofrio, A.; Inglima, G.; Roca, V.; Romano, M.; Romoli, M.; Sandoli, M.; Terrasi, F.; Fioretto, E.

1994-01-01

The 28 Si+ 64 Ni reaction at 163.8 MeV incident energy is studied by measuring in coincidence γ-rays and charged particles identified from Z 2 to Z = 16. The transition from quasi-elastic to more damped reactions is observed when the difference between the detected charge and the projectile one is increased. The strong influence of the particle decay on the measured γ-ray multiplicity is evidenced with the help of the statistical model computer code CASCADE. Dissipative events are well described in the rolling limit with excitation energy equally shared between the fragments. The overall agreement is lost for the fragments with the projectile charge which show a small value of the γ-multiplicity even for dissipative events. This is probably connected with the previously observed non statistical behavior of gamma rays emitted in coincidence with projectile-like fragments. In the alpha-spectrum measured in coincidence with gamma-rays, the deexcitation of fused systems is clearly separated from in flight emission of deep inelastic fragments. The low measured gamma-ray multiplicity for fusion events is qualitatively explained taking into account the effect of alpha-emission in the statistical decay. (orig.)

Differential expression of largemouth bass (Micropterus salmoides) estrogen receptor isotypes alpha, beta, and gamma by estradiol.

Science.gov (United States)

Sabo-Attwood, Tara; Kroll, Kevin J; Denslow, Nancy D

2004-04-15

The expression levels of three estrogen receptor (ER) isotypes alpha, beta, and gamma were quantified in female largemouth bass (Micropterus salmoides) (LMB) liver, ovary, brain, and pituitary tissues. ER alpha and beta expression predominated in the liver, while ERs beta and gamma predominated in the other tissues. Temporally in females, ER alpha was highly up-regulated, ER gamma was slightly up-regulated, and ER beta levels remained unchanged in the liver when plasma 17-beta estradiol (E2) and vitellogenin (Vtg) levels were elevated in the spring. In ovarian tissue from these same fish, all three ERs were maximally expressed in the fall, during early oocyte development and prior to peak plasma E2 levels. When males were injected with E2, ER alpha was highly inducible, ER gamma was moderately up-regulated, and ER beta levels were not affected. None of the ER isotypes were induced by E2 in gonadal tissues. These results combined suggest that the ERs themselves are not regulated in the same manner by E2, and furthermore, do not contribute equally to the transcriptional regulation of genes involved in fish reproduction such as Vtg.

Hanford beta-gamma personnel dosimeter prototypes and evaluation

International Nuclear Information System (INIS)

Fix, J.J.; Holbrook, K.L.; Soldat, K.L.

1983-04-01

Upgraded and modified Hanford dosimeter prototypes were evaluated for possible use at Hanford as a primary beta-gamma dosimeter. All prototypes were compatible with the current dosimeter card and holder design, as well as processing with the automated Hanford readers. Shallow- and deep-dose response was determined for selected prototypes using several beta sources, K-fluorescent x rays and filtered x-ray techniques. All prototypes included a neutron sensitive chip. A progressive evaluation of the performance of each of the upgrades to the current dosimeter is described. In general, the performance of the current dosimeter can be upgraded using individual chip sensitivity factors to improve precision and an improved algorithm to minimize bias. The performance of this dosimeter would be adequate to pass all categories of the ANSI N13.11 performance criteria for dosimeter procesors, provided calibration techniques compatible with irradiations adopted in the standard were conducted. The existing neutron capability of the dosimeter could be retained. Better dosimeter performance to beta-gamma radiation can be achieved by modifying the Hanford dosimeter so that four of the five chip positions are devoted to calculating these doses instead of the currently used two chip positions. A neutron sensitive chip was used in the 5th chip position, but all modified dosimeter prototypes would be incapable of discriminating between thermal and epithermal neutrons. An improved low energy beta response can be achieved for the current dosimeter and all prototypes considered by eliminating the security credential. Further improvement can be obtained by incorporating the 15-mil thick TLD-700 chips

The mirror symmetric centroid difference method for picosecond lifetime measurements via {gamma}-{gamma} coincidences using very fast LaBr{sub 3}(Ce) scintillator detectors

Energy Technology Data Exchange (ETDEWEB)

Regis, J.-M., E-mail: regis@ikp.uni-koeln.d [Institut fuer Kernphysik, Universitaet zu Koeln, Zuelpicher Str. 77, 50937 Koeln (Germany); Pascovici, G.; Jolie, J.; Rudigier, M. [Institut fuer Kernphysik, Universitaet zu Koeln, Zuelpicher Str. 77, 50937 Koeln (Germany)

2010-10-01

The ultra-fast timing technique was introduced in the 1980s and is capable of measuring picosecond lifetimes of nuclear excited states with about 3 ps accuracy. Very fast scintillator detectors are connected to an electronic timing circuit and detector vs. detector time spectra are analyzed by means of the centroid shift method. The very good 3% energy resolution of the nowadays available LaBr{sub 3}(Ce) scintillator detectors for {gamma}-rays has made possible an extension of the well-established fast timing technique. The energy dependent fast timing characteristics or the prompt curve, respectively, of the LaBr{sub 3}(Ce) scintillator detector has been measured using a standard {sup 152}Eu {gamma}-ray source. For any energy combination in the range of 200keVgamma}<}1500keV, the {gamma}-{gamma} fast timing characteristics is calibrated as a function of energy with an accuracy of 2-4 ps. An extension of the centroid shift method providing very attractive features for picosecond lifetime measurements is presented. The mirror symmetric centroid difference method takes advantage of the symmetry obtained when performing {gamma}-{gamma} lifetime measurements using a pair of almost identical very fast scintillator detectors. In particular cases, the use of the mirror symmetric centroid difference method also allows the direct determination of picosecond lifetimes, hence without the need of calibrating the prompt curve.

$\\beta$-delayed neutrons from oriented $^{137,139}$I and $^{87,89}$Br nuclei

CERN Document Server

Grzywacz, Robert; Stone, Nicholas; Köster, Ulli; Singh, Barlaj; Bingham, Carrol; Gaulard, S; Kolos, Karolina; Madurga, Miguel; Nikolov, J; Otsubo, T; Roccia, S; Veskovic, Miroslav; Walker, Phil; Walters, William

2013-01-01

We propose a world-­‐first measurement of the angular distribution of $\\beta$-­‐delayed n and $\\gamma$- radiation from oriented $^{137, 139}$I and $^{87,89}$Br nuclei, polarised at low temperature at the NICOLE facility. $\\beta$-­‐delayed neutron emission is an increasingly important decay mechanism as the drip line is approached and its detailed understanding is essential to phenomena as fundamental as the r‐process and practical as the safe operation of nuclear power reactors. The experiments offer sensitive tests of theoretical input concerning the allowed and first-­‐forbidden $\\beta$‐decay strength, the spin-­‐density of neutron emitting states and the partial wave barrier penetration as a function of nuclear deformation. In $^{137}$I and $^{87}$Br the decay feeds predominantly the ground state of the daughters $^{136}$Xe and $^{86}$Kr whereas in $^{139}$I and $^{89}$Br we will explore the use of n-$\\gamma$- coincidence to study neutron transitions to the first and second excited state...

CD147 is a regulatory subunit of the gamma-secretase complex inAlzheimer's disease amyloid beta-peptide production

Energy Technology Data Exchange (ETDEWEB)

Zhou, Shuxia; Zhou, Hua; Walian, Peter J.; Jap, Bing K.

2005-04-06

{gamma}-secretase is a membrane protein complex that cleaves the {beta}-amyloid precursor protein (APP) within the transmembrane region, following prior processing by {beta}-secretase, producing amyloid {beta}-peptides (A{beta}{sub 40} and A{beta}{sub 42}). Errant production of A{beta}-peptides that substantially increases A{beta}{sub 42} production has been associated with the formation of amyloid plaques in Alzheimer's disease patients. Biophysical and genetic studies indicate that presenilin-1 (Psn-1), which contains the proteolytic active site, and three other membrane proteins, nicastrin (Nct), APH-1, and PEN-2 are required to form the core of the active {gamma}-secretase complex. Here, we report the purification of the native {gamma}-secretase complexes from HeLa cell membranes and the identification of an additional {gamma}-secretase complex subunit, CD147, a transmembrane glycoprotein with two immunoglobulin-like domains. The presence of this subunit as an integral part of the complex itself was confirmed through co-immunoprecipitation studies of the purified protein from HeLa cells and solubilized complexes from other cell lines such as neural cell HCN-1A and HEK293. Depletion of CD147 by RNA interference was found to increase the production of A{beta} peptides without changing the expression level of the other {gamma}-secretase components or APP substrates while CD147 overexpression had no statistically significant effect on amyloid {beta}-peptide production, other {gamma}-secretase components or APP substrates, indicating that the presence of the CD147 subunit within the {gamma}-secretase complex directly down-modulates the production of A{beta}-peptides. {gamma}-secretase was first recognized through its role in the production of the A{beta} peptides that are pathogenic in Alzheimer's disease (AD) (1). {gamma}-secretase is a membrane protein complex with unusual aspartyl protease activity that cleaves a variety of type I membrane proteins

Formation of hydrogen fluoride by gamma and beta sterilisation in medical devices containing perfluoroheptane

International Nuclear Information System (INIS)

Zuendorf, Josef; Kremer, Stefan; Grueger, Thomas

2008-01-01

Infusion of hexadecafluoroheptane, a liquid perfluorocarbon released from repaired Althane dialysers was found to be the most probable reason for the deaths of 53 dialysis patients reported in the year 2001. This study focuses on toxic decomposition products generated due to gamma and beta sterilisation of hexadecafluoroheptane. The responsible dialysers were sterilised with a maximum dose of 45 kGy gamma irradiation. We investigated the influence of both 20-500 kGy gamma and beta irradiation on perfluoroheptane. Analysis of the irradiated samples verified the decomposition of perfluoroheptane in dependence on the dose of irradiation. Beta irradiation resulted in a higher degree of decomposition than the same dose of gamma irradiation. As decomposition products, hydrogen fluoride, CO 2 , and one saturated fluorinated hydrocarbon which could not be analysed exactly were identified. Even at 20 kGy gamma irradiation hydrogen fluoride was detectable. Our results provide evidence that hydrogen fluoride is generated as a highly toxic decomposition product when perfluoroheptane is sterilised with gamma irradiation as it was applied on the affected dialysers. There is no evidence of other toxic degradation products especially perfluoroisobutylene. Therefore, hydrogen fluoride or the dissociated fluoride ions might act as a toxic agent when medical devices containing liquid perfluorocarbons are sterilised by irradiation

Solved problems in analysis as applied to gamma, beta, Legendre and Bessel functions

CERN Document Server

Farrell, Orin J

2013-01-01

Nearly 200 problems, each with a detailed, worked-out solution, deal with the properties and applications of the gamma and beta functions, Legendre polynomials, and Bessel functions. The first two chapters examine gamma and beta functions, including applications to certain geometrical and physical problems such as heat-flow in a straight wire. The following two chapters treat Legendre polynomials, addressing applications to specific series expansions, steady-state heat-flow temperature distribution, gravitational potential of a circular lamina, and application of Gauss's mechanical quadrature

Endogenous PKI gamma limits the duration of the anti-apoptotic effects of PTH and beta-adrenergic agonists in osteoblasts.

Science.gov (United States)

Chen, Xin; Song, In-Hwan; Dennis, James E; Greenfield, Edward M

2007-05-01

PKI gamma knockdown substantially extended the anti-apoptotic effects of PTH and beta-adrenergic agonists, whereas PKI gamma overexpression decreased these effects. Therefore, inhibition of PKI gamma activity may provide a useful co-therapy in combination with intermittent PTH or beta-adrenergic agonists for bone loss in conditions such as osteoporosis. PTH has both catabolic and anabolic effects on bone, which are primarily caused by cAMP/protein kinase A (PKA) signaling and regulation of gene expression. We previously showed that protein kinase inhibitor-gamma (PKI gamma) is required for efficient termination of cAMP/PKA signaling and gene expression after stimulation with PTH or beta-adrenergic agonists. Inhibition of osteoblast apoptosis is thought to be an important, but transient, mechanism partly responsible for the anabolic effects of intermittent PTH. Therefore, we hypothesized that endogenous PKI gamma also terminates the anti-apoptotic effect of PTH. PKI gamma knockdown by antisense transfection or siRNA was used to examine the ability of endogenous PKI gamma to modulate the anti-apoptotic effects of PTH and beta-adrenergic agonists in ROS 17/2.8 cells. Knockdown of PKI gamma substantially extended the anti-apoptotic effects of PTH, whether apoptosis was induced by etoposide or dexamethasone. In contrast, overexpression of PKI gamma decreased the anti-apoptotic effect of PTH pretreatment. This study is also the first demonstration that beta-adrenergic agonists mimic the anti-apoptotic effects of PTH in osteoblasts. Moreover, PKI gamma knockdown also substantially extended this anti-apoptotic effect of beta-adrenergic agonists. Taken together, these results show that endogenous PKI gamma limits the duration of the anti-apoptotic effects of cAMP/PKA signaling in osteoblasts. Because significant individual variability exists in the anabolic responses to PTH therapy in current clinical treatment of osteoporosis, inhibition of PKI gamma activity may provide a

Hard beta and gamma emissions of 124I. Impact on occupational dose in PET/CT.

Science.gov (United States)

Kemerink, G J; Franssen, R; Visser, M G W; Urbach, C J A; Halders, S G E A; Frantzen, M J; Brans, B; Teule, G J J; Mottaghy, F M

2011-01-01

The hard beta and gamma radiation of 124I can cause high doses to PET/CT workers. In this study we tried to quantify this occupational exposure and to optimize radioprotection. Thin MCP-Ns thermoluminescent dosimeters suitable for measuring beta and gamma radiation were used for extremity dosimetry, active personal dosimeters for whole-body dosimetry. Extremity doses were determined during dispensing of 124I and oral administration of the activity to the patient, the body dose during all phases of the PET/CT procedure. In addition, dose rates of vials and syringes as used in clinical practice were measured. The procedure for dispensing 124I was optimized using newly developed shielding. Skin dose rates up to 100 mSv/min were measured when in contact with the manufacturer's vial containing 370 MBq of 124I. For an unshielded 5 ml syringe the positron skin dose was about seven times the gamma dose. Before optimization of the preparation of 124I, using an already reasonably safe technique, the highest mean skin dose caused by handling 370 MBq was 1.9 mSv (max. 4.4 mSv). After optimization the skin dose was below 0.2 mSv. The highly energetic positrons emitted by 124I can cause high skin doses if radioprotection is poor. Under optimized conditions occupational doses are acceptable. Education of workers is of paramount importance.

Calibration of radionuclides with decay trough beta emission or electron capture by liquid scintillation technique; Calibracao de radionuclideos que decaem por emissao beta ou por captura eletronica pela tecnica de cintilacao liquida

Energy Technology Data Exchange (ETDEWEB)

Loureiro, Jamir dos Santos

2000-02-01

In this work is reported a methodology a methodology for pure beta and electron capture radionuclides standardization, suing liquid scintillation technique. In this sense the CIEMAT/NIST method, recently utilized by international laboratories, was implemented and the lack in the Laboratorio Nacional das Radiacoes Ionizantes - LNMRI, of the Comissao Nacional de Energia Nuclear - CNEN, for adequate methodology to standardize this kind if radionuclides was filled, fact that was not present with alpha and gamma radionuclides. The implementation procedure evaluation was provided by concentration activity determination of the following radionuclides: {sup 14} C and {sup 90} Sr, pure beta emitters; {sup 55} Fe, electron capture decay; {sup 204} Tl, electron capture and beta decay and {sup 60} Co, beta-gamma emitter. In this way, a careful analysis of the implementation procedure with these radionuclides types, ranging on a broad energy spectral, was possible. To check the calibration results, intercomparisons among our measurements of these radionuclides and the reference values of the CIEMAT/Spain laboratory were provided. To check the calibration results, intercomparisons among our measurements of these radionuclides and the reference values of the CIEMAT/Spain laboratory were provided. Besides this intercomparisons, one was provided with a {sup 204} Tl solution, utilized in the international comparison recently promoted by BIPM, and another one with a {sup 60} C solution calibrated in LNMRI/CNEN previously by a relative calibration system, with a well type pressurized ionization chamber, and an absolute beta-gamma coincidence system, with a pill-box type proportional counter 4 {pi} geometry, coupled with a scintillator system with a sodium iodide cristal of 4x4 inches. The comparisons among LNMRI/CNEN results and the reference values, showed a small deviation of 1,32% for {sup 14} C, 0,40% for {sup 60} Co, 1,12% for {sup 55} Fe, 0,10% for {sup 90} Sr and 0,73% for {sup

Quantitative relations between beta-gamma mixed-field dosimeter responses and dose-equivalent conversion factors according to the testing standard

International Nuclear Information System (INIS)

Gupta, V.P.

1982-08-01

The conventional two-element personnel dosimeters, usually having two thick TLD (thermoluminescent dosimetry) ribbons, are used extensively for radiation protection dosimetry. Many of these dosimeters are used for the measurement of beta and gamma radiation doses received in mixed beta-gamma fields. Severe limitations exist, however, on the relative magnitudes and energies of these fields that may be measured simultaneously. Moreover, due to a well-known energy dependence of these dosimeters, particularly for the beta-radiations, systematic errors will occur whenever the differences in workplaces and calibration radiation energies exist. A simple mathematical approach is presented to estimate the deep and shallow dose equivalent values at different energies for such dosimeters. The formulae correlate the dosimeter responses and dose equivalent conversion factors at different energies by taking into account the guidelines of the adopted ANSI Standard N13.11 and the dosimetry practices followed by most dosimeter processors. This standard is to be used in a mandatory testing program in the United States

Radioelements: their detection and measurement; Les radioelements: detection et mesure

Energy Technology Data Exchange (ETDEWEB)

Grinberg, B. [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

1960-07-01

A brief review of the properties of nuclear radiations is followed by a description of the basic techniques used for their detection: autoradiography, methods using the ionisation of gases (ionisation chambers, proportional counters, Geiger-Muller counters), scintillation techniques. The principles of the different methods of measurement are explained, whether they concern the activity or the energy absorbed (dosimetry). This is followed by a description of the basic techniques (4 {pi} counter, defined solid angle, {beta}-{gamma} coincidences). (author) [French] Apres un bref rappel des proprietes des rayonnements nucleaires, on decrit les techniques fondamentales employees pour leur detection: autoradiographie, procedes utilisant l'ionisation des gaz (chambres d'ionisation, compteurs proportionnels, compteurs de Geiger-Muller), technique des scintillations. On expose le principe des differentes methodes de mesure concernant soit l'activite, soit l'energie absorbee (dosimetrie). Les techniques fondamentales (compteur 4 {pi}, angle solide defini, coincidences {beta}-{gamma}) sont ensuite decrites. (auteur)

True coincidence summing correction determination for 214Bi principal gamma lines in NORM samples

International Nuclear Information System (INIS)

Haddad, Kh.

2014-01-01

The gamma lines 609.3 and 1,120.3 keV are two of the most intensive γ emissions of 214 Bi, but they have serious true coincidence summing (TCS) effects due to the complex decay schemes with multi-cascading transitions. TCS effects cause inaccurate count rate and hence erroneous results. A simple and easy experimental method for determination of TCS correction of 214 Bi gamma lines was developed in this work using naturally occurring radioactive material samples. Height efficiency and self attenuation corrections were determined as well. The developed method has been formulated theoretically and validated experimentally. The corrections problems were solved simply with neither additional standard source nor simulation skills. (author)

Proton current measurements using the prompt gamma ray diagnostic technique

International Nuclear Information System (INIS)

Leeper, R.J.; Burns, E.J.T.; Johnson, D.J.; McMurtry, W.M.

1981-01-01

Prompt gamma ray signals from the nuclear reaction 7 Li(p,γ) 8 Be have been used to make time resolved proton current measurements. In these measurements, the proton beam was allowed to strike cylindrical thick lithium metal targets. The time integrated proton current was measured using gamma activation of copper via the reaction 63 Cu(γ,n) 62 Cu(β+). The positron activity of the copper sample was easily measured using coincidence counting techniques. The number of 62 Cu atoms produced per proton incident on a thick Li metal target was determined with separate calibration runs performed on the Sandia 2.5 MeV Van de Graaff accelerator. The time history of the prompt gamma production was measured using six EGG NPM-54 scintillator photomultiplier combinations shielded by 96.5 cm of concrete and 5.1 cm of Pb. The use of six scintillator photomultiplier combinations was necessary to increase the statistical precision of the data. The normalization of the prompt gamma time history data with the total time integrated proton-current measurement yielded the absolute time resolved proton current on target. Data from runs performed on the Sandia Proto I accelerator will be presented

The LPCTrap experiment: measurement of the {beta}-{nu} angular correlation in {sup 6}He{sup +} decay using a transparent Paul trap

Energy Technology Data Exchange (ETDEWEB)

Velten, Ph., E-mail: velten@lpccaen.in2p3.fr; Ban, G.; Durand, D.; Flechard, X.; Lienard, E.; Mauger, F.; Mery, A.; Naviliat-Cuncic, O.; Rodriguez, D.; Thomas, J. C. [Universite de Caen, LPC Caen, ENSICAEN (France)

2011-07-15

The LPCTrap experiment is devoted to the precise measurement of the {beta}-{nu} angular correlation parameter, a{sub {beta}{nu}}, in the pure Gamow-Teller decay of {sup 6}He{sup +}. This experiment is motivated by the search of the presence of tensor type contributions in the weak interaction. The radioactive source is confined in a transparent Paul trap installed at LIRAT, the low energy beam line of the SPIRAL facility. The {beta}-{nu} correlation is studied by measuring the time of flight of the recoil ions detected in coincidence with the {beta} particles. During the last experiment, a total of 4 Multiplication-Sign 10{sup 6} coincidence events have been recorded which would enable to determine the coefficient with a statistical uncertainty of 0.5%. The status of the analysis is presented in this contribution.

Positron emission measurement with coincidence counting technic using large plastic scintillators

International Nuclear Information System (INIS)

Espinasse, P.; Minchella, P.

1990-01-01

For measuring positron emission of a large organ such as the brain for example, a device has been built with two cylindric plastic scintillators allowing the detection in coincidence of the 511 keV gamma rays without any spectrometry. The main results are for the sensitivity at the center of the field with 22 Na source in water: 240 ips/MBq; background = 12 ips, and for the countloss due to the deadtime >5% with 42 MBq. Sensitivity is almost uniform on the main axis between the probes. It falls to about 50% on the edges of a central diameter of 20 cm. The performances could certainly be improved by using modern rapid photomultipliers [fr

Estimation of potassium concentration in coconut water by beta radioactivity measurement

International Nuclear Information System (INIS)

Reddy, P.J.; Narayani, K.; Bhade, S.P.D.; Anilkumar, S.; Kolekar, R.V.; Singh, Rajvir; Pradeepkumar, K.S.

2014-01-01

Potassium is widely distributed in soil, in all vegetable, fruits and animal tissues. Approximately half the radioactivity found in humans comes from 40 K. Potassium is an essential element in our diet since it is required for proper nerve and muscle function, as well as for maintaining the fluid balance of cells and heart rhythm. Potassium can enter the body mainly consuming fruits, vegetables and food. Tender coconut water is consumed widely as natural refreshing drink which is rich in potassium. The simple way to determine 40 K activity is by gamma ray spectrometry. However, the low abundance of this gamma photon makes the technique less sensitive compared to gross beta measurement. Many analytical methods are reported for potassium estimation which is time consuming and destructive in nature. A unique way to estimate 40 K by beta activity is by Cerenkov Counting technique using Liquid Scintillation Analyzer. Also much lower detection limit is achieved, allowing for greater precision. In this work, we have compared two methods to arrive at the potassium concentration in tender and matured coconut water by measuring 40 K. One is non-scintillator method based on measurement of the Cerenkov radiation generated from the high-energy β of 40 K. The second method is based on beta activity measurement using low background Gas flow counter

The beta(+) decay and cosmic-ray half-life of Mn-54

Science.gov (United States)

Dacruz, M. T. F.; Norman, E. B.; Chan, Y. D.; Garcia, A.; Larimer, R. M.; Lesko, K. T.; Stokstad, R. G.; Wietfeldt, F. E.

1993-03-01

We performed a search for the beta(+) branch of Mn-54 decay. As a cosmic ray, Mn-54, deprived of its atomic electrons, can decay only via beta(+) and beta(-) decay, with a half-life of the order of 106 yr. This turns Mn-54 into a suitable cosmic chronometer for the study of cosmic-ray confinement times. We searched for coincident back-to-back 511-keV gamma-rays using two germanium detectors inside a Nal(Tl) annulus. An upper limit of 2 x 10-8 was found for the beta(+) decay branch, corresponding to a lower limit of 13.7 for the log ft value.

Evaluation of in-plant neutron coincidence counters for the measurement of molten salt extraction residues

International Nuclear Information System (INIS)

Langner, D.G.; Russo, P.A.; Wachter, J.R.

1993-01-01

Americium is extracted from plutonium by a molten salt extraction (MSE) process. The residual americium-laden salts are a significant waste stream in this pyrochemical purification process. Rapid assay of MSE residues is desirable to minimize the exposure of personnel to these often high-level emissions. However, the quantitative assay of plutonium in MSE residues is difficult. Variable, unknown (a,n) rates and variable emitted-neutron energy spectra preclude the use of standard neutron coincidence counting techniques with old-generation neutron coincidence counters. Gamma-ray assay methods have not been successful with some residues because of random lumps of plutonium metal. In this paper, we present measurements of MSE residues with two state-of-the-art neutron coincidence counters at the Los Alamos Plutonium Processing Facility: an in-line counter built for the assay of bulk waste material and the pyrochemical multiplicity counter that underwent test and evaluation at that facility. Both of these counters were designed to minimize the effects on measurements of variations in the sample geometry and variable energy spectra of emitted neutrons. These results are compared to measurements made with an HLNCII and with a 20-yr-old in-line well counter. The latter two counters are not optimized in ft sense. We conclude that the newer counters provide significantly improved assay results. The pyrochemical multiplicity counter operated in the conventional coincidence mode provided the best assays overall

Thermodynamics in Gliomas: Interactions between the Canonical WNT/Beta-Catenin Pathway and PPAR Gamma

Directory of Open Access Journals (Sweden)

Alexandre Vallée

2017-05-01

Full Text Available Gliomas cells are the site of numerous metabolic and thermodynamics abnormalities with an increasing entropy rate which is characteristic of irreversible processes driven by changes in Gibbs energy, heat production, intracellular acidity, membrane potential gradient, and ionic conductance. We focus our review on the opposing interactions observed in glioma between the canonical WNT/beta-catenin pathway and PPAR gamma and their metabolic and thermodynamic implications. In gliomas, WNT/beta-catenin pathway is upregulated while PPAR gamma is downregulated. Upregulation of WNT/beta-catenin signaling induces changes in key metabolic enzyme that modify their thermodynamics behavior. This leads to activation pyruvate dehydrogenase kinase 1(PDK-1 and monocarboxylate lactate transporter 1 (MCT-1. Consequently, phosphorylation of PDK-1 inhibits pyruvate dehydrogenase complex (PDH. Thus, a large part of pyruvate cannot be converted into acetyl-CoA in mitochondria and in TCA (tricarboxylic acid cycle. This leads to aerobic glycolysis despite the availability of oxygen, named Warburg effect. Cytoplasmic pyruvate is, in major part, converted into lactate. The WNT/beta-catenin pathway induces also the transcription of genes involved in cell proliferation, cell invasiveness, nucleotide synthesis, tumor growth, and angiogenesis, such as c-Myc, cyclin D1, PDK. In addition, in gliomas cells, PPAR gamma is downregulated, leading to a decrease in insulin sensitivity and an increase in neuroinflammation. Moreover, PPAR gamma contributes to regulate some key circadian genes. Abnormalities in the regulation of circadian rhythms and dysregulation in circadian clock genes are observed in gliomas. Circadian rhythms are dissipative structures, which play a key role in far-from-equilibrium thermodynamics through their interactions with WNT/beta-catenin pathway and PPAR gamma. In gliomas, metabolism, thermodynamics, and circadian rhythms are tightly interrelated.

Solute transport and the prediction of breakaway oxidation in gamma + beta Ni-Cr-Al alloys

Science.gov (United States)

Nesbitt, J. A.; Heckel, R. W.

1984-01-01

The Al transport and the condition leading to breakaway oxidation during the cyclic oxidation of gamma + beta NiCrAl alloys have been studied. The Al concentration/distance profiles were measured after various cyclic oxidation exposures at 1200 C. It was observed that cyclic oxidation results in a decreasing Al concentration at the oxide/metal interface, maintaining a constant flux of Al to the Al2O3 scale. It was also observed that breakaway oxidation occurs when the Al concentration at the oxide/metal interface approaches zero. A numerical model was developed to simulate the diffusional transport of Al and to predict breakaway oxidation in gamma + beta NiCrAl alloys undergoing cyclic oxidation. In a comparison of two alloys with similar oxide spalling characteristics, the numerical model was shown to predict correctly the onset of breakaway oxidation in the higher Al-content alloy.

Patterns of alpha, beta and gamma diversity of the herpetofauna in Mexico’s Pacific lowlands and adjacent interior valleys

Directory of Open Access Journals (Sweden)

García, A.

2007-12-01

Full Text Available The latitudinal distribution patterns of alpha, beta and gamma diversity of reptiles, amphibians and herpetofauna were analyzed using individual binary models of potential distribution for 301 species predicted by ecological modelling for a grid of 9,932 quadrants of ~25 km2 each. We arranged quadrants in 312 latitudinal bands in which alpha, beta and gamma values were determined. Latitudinal trends of all scales of diversity were similar in all groups. Alpha and gamma responded inversely to latitude whereas beta showed a high latitudinal fluctuation due to the high number of endemic species. Alpha and gamma showed a strong correlation in all groups. Beta diversity is an important component of the herpetofauna distribution patterns as a continuous source of species diversity throughout the region.

Effect of beta and gamma neurofeedback on memory and intelligence in the elderly

NARCIS (Netherlands)

Staufenbiel, S.M.; Brouwer, A.M.; Keizer, A.W.; Wouwe, N.C. van

2014-01-01

Recent research showed a correlation between cognitive decline and a decrease of EEG gamma activity. In the present double-blind randomized control study, we investigated whether gamma and beta neurofeedback protocols, that have been shown to modulate performance on cognitive control and memory in

Calibration of radionuclides with decay trough beta emission or electron capture by liquid scintillation technique

International Nuclear Information System (INIS)

Loureiro, Jamir dos Santos

2000-02-01

In this work is reported a methodology a methodology for pure beta and electron capture radionuclides standardization, suing liquid scintillation technique. In this sense the CIEMAT/NIST method, recently utilized by international laboratories, was implemented and the lack in the Laboratorio Nacional das Radiacoes Ionizantes - LNMRI, of the Comissao Nacional de Energia Nuclear - CNEN, for adequate methodology to standardize this kind if radionuclides was filled, fact that was not present with alpha and gamma radionuclides. The implementation procedure evaluation was provided by concentration activity determination of the following radionuclides: 14 C and 90 Sr, pure beta emitters; 55 Fe, electron capture decay; 204 Tl, electron capture and beta decay and 60 Co, beta-gamma emitter. In this way, a careful analysis of the implementation procedure with these radionuclides types, ranging on a broad energy spectral, was possible. To check the calibration results, intercomparisons among our measurements of these radionuclides and the reference values of the CIEMAT/Spain laboratory were provided. To check the calibration results, intercomparisons among our measurements of these radionuclides and the reference values of the CIEMAT/Spain laboratory were provided. Besides this intercomparisons, one was provided with a 204 Tl solution, utilized in the international comparison recently promoted by BIPM, and another one with a 60 C solution calibrated in LNMRI/CNEN previously by a relative calibration system, with a well type pressurized ionization chamber, and an absolute beta-gamma coincidence system, with a pill-box type proportional counter 4 π geometry, coupled with a scintillator system with a sodium iodide cristal of 4x4 inches. The comparisons among LNMRI/CNEN results and the reference values, showed a small deviation of 1,32% for 14 C, 0,40% for 60 Co, 1,12% for 55 Fe, 0,10% for 90 Sr and 0,73% for 204 Tl. For the BIPM solution the deviation was 0,46% and for 60 Co

Study of the neutron-rich nuclei with N=21, sup 3 sup 5 Si and sup 3 sup 3 Mg, by beta decay of sup 3 sup 5 Al and sup 3 sup 3 Na

CERN Document Server

Nummela, S; Caurier, E; Courtin, S; Dessagne, P; Holmlund, E; Jokinen, A; Knipper, A; Le Scornet, G; Mieh, C; Nowacki, F; Lyapin, L G; Oinonen, M; Poirier, E; Radivojevic, Z; Ramdhane, M; Trzaska, W H; Walter, G; Äystö, J

2002-01-01

The first information on the level structure of the N=21 nuclei, sup 3 sup 5 Si and sup 3 sup 3 Mg, has been obtained by the beta decay study of sup 3 sup 5 Al and sup 3 sup 3 Na, produced by fragmentation of an UC target with 1.4 GeV protons at CERN/ISOLDE. The experimental technique involved beta-gamma, beta-gamma-gamma, and beta-n-gamma coincidences, neutron spectra being obtained by time of flight measurements. Gamma detection was made either using large Ge counters or small BaF sub 2 scintillators (for lifetime measurements). In the case of the sup 3 sup 5 Al decay, (T sub 1 sub / sub 2 =41.6(2.2) ms), a simple structure has been found for the level scheme of sup 3 sup 5 Si (Z=14, N=21) which has been interpreted with the level sequence : 7/2 sup - , 3/2 sup - and 3/2 sup + corresponding respectively to the ground state and the states at 910 and 974 keV. The life-time of the 974 keV [T sub 1 sub / sub 2 =5.9(6) ns] is found consistent with the proposed level scheme and multipolarities. The investigation ...

Differential coincidence circuit in the 10{sup -10} second region (1960); Circuit de coincidence differentiel dans le domaine de 10{sup -10} seconde (1960)

Energy Technology Data Exchange (ETDEWEB)

Van Zurk, R [Commissariat a l' Energie Atomique, Lab. de Physique Nucleaire, Grenoble (France).Centre d' Etudes Nucleaires; [Grenoble-1 Univ., 38 (France); [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1960-07-01

A coincidence circuit of low resolution time using the differential coincidence Bay principle is described. It uses three 6BN6 tubes ordered to chronotron structure. Results with Radiotechnique 56 AVP photomultipliers and for {sup 60}Co {gamma}-{gamma} coincidences are 4,6.10{sup -10} s (full width at half maximum) if the efficiency is {epsilon} = 40 per cent and also 7,2.10{sup -10} s if {epsilon} = 85 per cent. (author) [French] Un circuit de coincidence differentiel du type de Bay, utilise en selecteur en temps a canal mobile, a ete construit pour la mesure des periodes {gamma} et des periodes d'annihilation du positon dans differents materiaux. Il comporte trois tubes 6BN6 disposes en structure chronotron. On a utilise les nouveaux photomultiplicateurs 56 AVP avec scintillateur plastique. Avec les coincidences {gamma}-{gamma} du {sup 60}Co, on obtient 2T 4,6.10{sup -10} s avec une efficacite de 40 pour cent et 2T = 7,2.10{sup -10} s avec une efficacite de 85 pour cent. (auteur)

Principle of coincidence method and application in activity measurement

International Nuclear Information System (INIS)

Li Mou; Dai Yihua; Ni Jianzhong

2008-01-01

The basic principle of coincidence method was discussed. The basic principle was generalized by analysing the actual example, and the condition in theory of coincidence method was brought forward. The cause of variation of efficiency curve and the effect of dead-time in activity measurement were explained using the above principle and condition. This principle of coincidence method provides the foundation in theory for activity measurement. (authors)

Rearrangement of beta,gamma-unsaturated esters with thallium trinitrate: synthesis of indans bearing a beta-keto ester moiety

Directory of Open Access Journals (Sweden)

Silva Jr. Luiz F.

2006-01-01

Full Text Available The rearrangement of beta,gamma-unsaturated esters, such as 2-(3,4-dihydronaphthalen-1-yl-propionic acid ethyl ester, with thallium trinitrate (TTN in acetic acid leads to 3-indan-1-yl-2-methyl-3-oxo-propionic acid ethyl ester in good yield, through a ring contraction reaction. The new indans thus obtained feature a beta-keto ester moiety, which would be useful for further functionalization.

Performances evaluation of the coincidence detection on a gamma-camera

International Nuclear Information System (INIS)

Dreuille, O. de; Gaillard, J.F.; Brasse, D.; Bendriem, B.; Groiselle, C.; Rocchisani, J.M.; Moretti, J.L.

2000-01-01

The performance of the VERTEX gamma-camera (ADAC) working in coincidence mode are investigated using a protocol derived from the NEMA and IEC recommendations. With a field of view determined by two rectangular detectors (50.8 cm x 40 cm) composed of NaI crystal, this camera allows a 3-D acquisition with different energy window configurations: photopeak-photopeak only (PP) and photopeak-photopeak + photopeak-Compton (PC). An energy resolution of 11% and a scatter fraction of 27% and 33% for the 3D-PP and 3D-PC mode respectively are the main significant results of our study. The spatial resolution equals 5.9 mm and the limit of the detectability ranges from 16 mm to 13 mm for a contrast of 2.5: as a function of the random estimation, the maximum of the Noise Equivalent Count rate varies from 3 kcps to 4.5 kcps for the PP mode and from 3.85 kcps to 6.1 kcps for the PC mode. These maxima are reached for a concentration of 8 kBq/ml for the PP mode and 5 kBq/ml for the PC mode. These values are compared with the results obtained by other groups for the VERTEX gamma camera and several dedicated PET systems. (authors)

Evaluation of gamma-ray intensities

International Nuclear Information System (INIS)

Yoshizawa, Yasukazu; Inoue, Hikaru; Hoshi, Masaharu; Shizuma, Kiyoshi; Iwata, Yosei.

1980-04-01

Relative intensities and intensities per decay of gamma rays were evaluated for 16 nuclides, 22 Na, 24 Na, 46 Sc, 54 Mn, 60 Co, 85 Sr, 88 Y, 95 Nb, sup(108m)Ag, 134 Cs, 133 Ba, 139 Ce, sup(180m)Hf, 198 Au, 203 Hg and 207 Bi. For most of these nuclides disintegration rates can be determined by means of β-γ or X-γ coincidence method. Since decay schemes of these nuclides are established, intensities per decay of strong gamma rays were accurately evaluated by using weak beta-ray branching ratios, relative gamma-ray intensities and internal conversion coefficients. Half-lives of the nuclides were also evaluated. Use of the nuclides, therefore, are recommended for precision intensity calibration of the detectors. (author)

Evaluation of beta-decay III. The complex gamma function

International Nuclear Information System (INIS)

Wilkinson, D.H.

1993-05-01

Two real, analytical, approximations for the square of the modulus of the complex gamma function as it appears in F(Z, W), the Fermi function for beta-decay, are evaluated; an accuracy bettering 10 -4 % can easily be achieved for all electron energies throughout the periodic table. (author). 3 refs., 1 tab., 7 figs

Disintegration rate of Tc -99m and In -111 radioactive solutions in coincidence systems

International Nuclear Information System (INIS)

Brito, Andreia Barreto de

2011-01-01

The 111 In and 99 mTc standardization in a 4πβ-γ coincidence system is described. The 111 In was produced by the reaction of 111 Cd (p, n) 111 In in the cyclotron. The 111 In decays with a half life of 2.8 days by electron capture process, populating the excited levels of 111 Cd, emitting two main gamma rays with energies of 171 keV and 245 keV. The 99m Tc decay with a half life of 6.007 h for isomeric transition, from the radioactive decay of 99 Mo. 111 In standardization was carried out in a 4πβ-γ system, consisted of a gas flow proportional counter with 4π geometry coupled to a pair of NaI(Tl) scintillation counter with conventional electronics. The gamma window was set comprising the (171 keV + 245 keV) total absorption energy peaks. The choice of the window was based on the analysis of the extrapolation curves prediction, obtained by Monte Carlo simulation. The 99 mTc standardization has been accomplished by the 4πβ-γ coincidence method using a thin window proportional counter in a 4π geometry coupled to a single NaI(Tl) scintillation counter. The beta efficiency was varied by electronic discrimination using a software coincidence counting system (SCS). Two windows were selected for the gamma channel: one at 140 keV gamma ray and the other at 20 keV X ray total absorption peaks. The result of the experimental activity of 111 In two solutions agree with the results obtained by Monte Carlo simulation. The experimental activities of 99m Tc for the two gamma windows are in agreement within the experimental uncertainty, indicating that the adopted methodology is adequate. (author)

Scintillation characteristics of phosphich-detector for detection of beta- and gamma-radiations

CERN Document Server

Ananenko, A A; Gavrilyuk, V

2002-01-01

The results of the study on the influence of individual peculiarities of the compound scintillation detector structure on the value and stability of the light yield by the gamma- and beta-radiation combined registration are presented. The phosphich detector is manufactured from the sodium iodide monocrystal, activated by thallium, and the scintillation plastic on the polystyrol basis. The comparison of the experimental results with the mathematical modeling data revealed certain regularities of the process of forming the phosphich detector light signal. The recommendations are worked out by means whereof the following characteristics of the scintillation unit: the light yield and its stability, amplitude resolution and the peak-to-valley ratio by the gamma- and beta-radiation registration were improved

Reproduction of the coincidence effect in gamma ray spectrometry by using Monte Carlo method

International Nuclear Information System (INIS)

Park, S. H.; Kim, J. K.; Lee, S. H.

2001-01-01

Scintillation detector such as NaI(TI), or semiconductor detector, such as HPGe, are used for Measurement/Assessment of the radiation type and radiation activity. The measured energy spectrum are used for measuring the radiation type and activity. Corrections for true coincidence due to emit more than 2 photons at the same time and random coincidence due to measuring system when increasing of the radiation intensity. For accurate assessment, measurement with adequate measure system is performed, and corrections for coincidence are performed in the hardware aspect and software aspect. In general, there are limitations or difficulties in measurement of radiation assessment, computational simulation is instead used. In simulation, it has much advantages than measurement in technically, timely, and financially, it is widely used instead of measurement. In this study, the method to reproduce of the coincidence effect was proposed by using monte carlo method

Standardization of low energy beta and beta-gamma complex emitters by the tracer and the efficiency extrapolation methods

International Nuclear Information System (INIS)

Sahagia, M.

1978-01-01

The absolute standardization of radioactive solutions of low energy beta emitters and beta-gamma emitters with a high probability of disintegration to the ground state is described; the tracer and the efficiency extrapolation methods were used. Both types of radionuclides were mathematically and physically treated in an unified manner. The theoretical relations between different beta spectra were calculated according to Williams' model and experimentally verified for: 35 S + 60 Co, 35 S + 95 Nb, 147 Pm + 60 Co, 14 C + 95 Nb and two beta branches of 99 Mo. The optimum range of beta efficiency variation was indicated. The basic supposition that all beta efficieny tend to unity in the same time was experimentally verified, using two 192 Ir beta branches. Four computer programs, written in the FORTRAN IV language, were elaborated, for the adequate processing of the experimental data. Good precision coefficients according to international standards were obtained in the absolute standardization of 35 S, 147 Pm, 99 Mo solutions. (author)

Coincidence measurements of FFTF breeder fuel subassemblies

International Nuclear Information System (INIS)

Eccleston, G.W.; Foley, J.E.; Krick, M.; Menlove, H.O.; Goris, P.; Ramalho, A.

1984-04-01

A prototype coincidence counter developed to assay fast breeder reactor fuel was used to measure four fast-flux test facility subassemblies at the Hanford Engineering Development Laboratory in Richland, Washington. Plutonium contents in the four subassemblies ranged between 7.4 and 9.7 kg with corresponding 240 Pu-effective contents between 0.9 and 1.2 kg. Large count rates were observed from the measurements, and plots of the data showed significant multiplication in the fuel. The measured data were corrected for deadtime and multiplication effects using established formulas. These corrections require accurate knowledge of the plutonium isotopics and 241 Am content in the fuel. Multiplication-corrected coincidence count rates agreed with the expected count rates based on spontaneous fission-neutron emission rates. These measurements indicate that breeder fuel subassemblies with 240 Pu-effective contents up to 1.2 kg can be nondestructively assayed using the shift-register electronics with the prototype counters. Measurements using the standard Los Alamos National Laboratory shift-register coincidence electronics unit can produce an assay value accurate to +-1% in 1000 s. The uncertainty results from counting statistics and deadtime-correction errors. 3 references, 8 figures, 8 tables

Thermodynamics in Neurodegenerative Diseases: Interplay Between Canonical WNT/Beta-Catenin Pathway-PPAR Gamma, Energy Metabolism and Circadian Rhythms.

Science.gov (United States)

Vallée, Alexandre; Lecarpentier, Yves; Guillevin, Rémy; Vallée, Jean-Noël

2018-03-23

Entropy production rate is increased by several metabolic and thermodynamics abnormalities in neurodegenerative diseases (NDs). Irreversible processes are quantified by changes in the entropy production rate. This review is focused on the opposing interactions observed in NDs between the canonical WNT/beta-catenin pathway and PPAR gamma and their metabolic and thermodynamic implications. In amyotrophic lateral sclerosis and Huntington's disease, WNT/beta-catenin pathway is upregulated, whereas PPAR gamma is downregulated. In Alzheimer's disease and Parkinson's disease, WNT/beta-catenin pathway is downregulated while PPAR gamma is upregulated. The dysregulation of the canonical WNT/beta-catenin pathway is responsible for the modification of thermodynamics behaviors of metabolic enzymes. Upregulation of WNT/beta-catenin pathway leads to aerobic glycolysis, named Warburg effect, through activated enzymes, such as glucose transporter (Glut), pyruvate kinase M2 (PKM2), pyruvate dehydrogenase kinase 1(PDK1), monocarboxylate lactate transporter 1 (MCT-1), lactic dehydrogenase kinase-A (LDH-A) and inactivation of pyruvate dehydrogenase complex (PDH). Downregulation of WNT/beta-catenin pathway leads to oxidative stress and cell death through inactivation of Glut, PKM2, PDK1, MCT-1, LDH-A but activation of PDH. In addition, in NDs, PPAR gamma is dysregulated, whereas it contributes to the regulation of several key circadian genes. NDs show many dysregulation in the mediation of circadian clock genes and so of circadian rhythms. Thermodynamics rhythms operate far-from-equilibrium and partly regulate interactions between WNT/beta-catenin pathway and PPAR gamma. In NDs, metabolism, thermodynamics and circadian rhythms are tightly interrelated.

Analysis of minor elements in steel by coincidence method in deuteron-induced prompt gamma-ray emission (D-PIGE)

International Nuclear Information System (INIS)

Ene, Antoaneta; Popescu, I.; Badica, T.; Olariu, Agata; Besliu, C.

2000-01-01

Among the factors affecting the sensitivity of PIGE method (particle-induced prompt gamma-ray emission) frequently discussed in the literature, the background in the γ-ray spectrum holds a prominent place. In this work the limits of detection of minor elements in a standard steel sample (Euronorm rm No. 085/1) irradiated with 5 MeV deuterons have been determined by the regular d-PIGE method and with the selection of the (d,n) reaction channel by measuring γ--n coincidences following the reaction steel + deuterons. This approach has resulted in a significant improvement of the sensitivity of the analysis, reducing the background in prompt gamma ray spectrum by eliminating the γ--rays observed in the singular spectrum which arises from the reaction channels (d, d'), (d, γ), (d, p), (d, 3 He), (d, α) and (d, t). From the singular spectrum we could establish the presence of the elements S, Pb, Mo, Co, V, P, O, Si, Zn, Mn, Cu, Sb, C, Al, N, As, Ti and Fe. The γ--n coincidence spectrum, obtained as a result of the selection of the γ- transitions via the reaction channel (d, n), is substantially different from the singular γ--spectrum, exhibiting γ- lines of rather high intensity to be used in the analyses on a reduced background. The coincidence spectrum shows lines from S, Mo, Co, Zn, Si, Mn, V, Sb, Ti, As, Ni, Cr, P, O, Al, Cu and Fe. We also made a comparative study with the published results using 5.5 MeV protons as projectiles. While for a given energy of the protons not all the elements of interest lead to a (p, n) reaction (C, O, P, S, Si etc.), most of the (d, n) reactions are exoergic. On the other side, the identification of the elements is more difficult in the case of deuterons. (authors)

Field measurement and interpretation of beta doses and dose rates

International Nuclear Information System (INIS)

Selby, J.M.; Swinth, K.L.; Hooker, C.D.; Kenoyer, J.L.

1983-01-01

A wide variety of portable survey instruments employing GM, ionization chamber and scintillation detectors exist for the measurement of gamma exposure rates. Often these same survey instruments are used for monitoring beta fields. This is done by making measurements with and without a removable shield which is intended to shield out the non-penetrating component (beta) of the radiation field. The difference does not correspond to an absorbed dose rate for the beta field due to a variety of factors. Among these factors are the dependence on beta energy, source-detector geometries, mixed fields and variable ambient conditions. Attempting to use such measurements directly can lead to errors as high as a factor of 100. In many instances correction factors have been derived, that if properly applied, can reduce these errors substantially. However, this requires some knowledge of the beta spectra, calibration techniques and source geometry. This paper discusses some aspects of the proper use of instruments for beta measurements including the application of appropriate correction factors. Ionization type instruments are commonly used to measure beta dose rates. Through design and calibration these instruments will give an accurate reading only for uniform irradiation of the detection volume. Often in the field it is not feasible to meet these conditions. Large area uniform distributions of activity are not generally encountered and it is not possible to use large source-to-detector distances due to beta particle absorption in air. An example of correction factors required for various point sources is presented when a cutie pie ionization chamber is employed. The instrument reading is multiplied by the appropriate correction factor to obtain the dose rate at the window. When a different detector is used or for other geometries, a different set of correction factors must be used

Circadian rhythms, Wnt/beta-catenin pathway and PPAR alpha/gamma profiles in diseases with primary or secondary cardiac dysfunction

Directory of Open Access Journals (Sweden)

Yves eLecarpentier

2014-11-01

Full Text Available Circadian clock mechanisms are far-from-equilibrium dissipative structures. Peroxisome proliferator-activated receptors (PPAR alpha, beta/delta and gamma play a key role in metabolic regulatory processes, particularly in heart muscle. Links between circadian rhythms (CRs and PPARs have been established. Mammalian CRs involve at least two critical transcription factors, CLOCK and BMAL1 (Gekakis et al., 1998; Hogenesch et al., 1998. PPAR gamma plays a major role in both glucose and lipid metabolisms and presents circadian properties which coordinate the interplay between metabolism and CRs. PPAR gamma is a major component of the vascular clock. Vascular PPAR gamma is a peripheral regulator of cardiovascular rhythms controlling circadian variations in blood pressure and heart rate through BMAL1. We focused our review on diseases with abnormalities of CRs and with primary or secondary cardiac dysfunction. Moreover, these diseases presented changes in the Wnt/beta-catenin pathway and PPARs, according to two opposed profiles. Profile 1 was defined as follows: inactivation of the Wnt/beta-catenin pathway with increased expression of PPAR gamma. Profile 2 was defined as follows: activation of the Wnt/beta-catenin pathway with decreased expression of PPAR gamma. A typical profile 1 disease is arrhythmogenic right ventricular cardiomyopathy, a genetic cardiac disease which presents mutations of the desmosomal proteins and is mainly characterized by fatty acid accumulation in adult cardiomyocytes mainly in the right ventricle. The link between PPAR gamma dysfunction and desmosomal genetic mutations occurs via inactivation of the Wnt/beta-catenin pathway presenting oscillatory properties. A typical profile 2 disease is type 2 diabetes, with activation of the Wnt/beta-catenin pathway and decreased expression of PPAR gamma. CRs abnormalities are present in numerous pathologies such as cardiovascular diseases, sympathetic/parasympathetic dysfunction

Gamma and Beta Oscillations in Human MEG Encode the Contents of Vibrotactile Working Memory

Directory of Open Access Journals (Sweden)

Alexander H. von Lautz

2017-12-01

Full Text Available Ample evidence suggests that oscillations in the beta band represent quantitative information about somatosensory features during stimulus retention. Visual and auditory working memory (WM research, on the other hand, has indicated a predominant role of gamma oscillations for active WM processing. Here we reconciled these findings by recording whole-head magnetoencephalography during a vibrotactile frequency comparison task. A Braille stimulator presented healthy subjects with a vibration to the left fingertip that was retained in WM for comparison with a second stimulus presented after a short delay. During this retention interval spectral power in the beta band from the right intraparietal sulcus and inferior frontal gyrus (IFG monotonically increased with the to-be-remembered vibrotactile frequency. In contrast, induced gamma power showed the inverse of this pattern and decreased with higher stimulus frequency in the right IFG. Together, these results expand the previously established role of beta oscillations for somatosensory WM to the gamma band and give further evidence that quantitative information may be processed in a fronto-parietal network.

Interactions Between the Canonical WNT/Beta-Catenin Pathway and PPAR Gamma on Neuroinflammation, Demyelination, and Remyelination in Multiple Sclerosis.

Science.gov (United States)

Vallée, Alexandre; Vallée, Jean-Noël; Guillevin, Rémy; Lecarpentier, Yves

2018-05-01

Multiple sclerosis (MS) is marked by neuroinflammation and demyelination with loss of oligodendrocytes in the central nervous system. The immune response is regulated by WNT/beta-catenin pathway in MS. Activated NF-kappaB, a major effector of neuroinflammation, and upregulated canonical WNT/beta-catenin pathway positively regulate each other. Demyelinating events present an upregulation of WNT/beta-catenin pathway, whereas proper myelinating phases show a downregulation of WNT/beta-catenin pathway essential for the promotion of oligodendrocytes precursors cells proliferation and differentiation. The activation of WNT/beta-catenin pathway results in differentiation failure and impairment in remyelination. However, PI3K/Akt pathway and TCF7L2, two downstream targets of WNT/beta-catenin pathway, are upregulated and promote proper remyelination. The interactions of these signaling pathways remain unclear. PPAR gamma activation can inhibit NF-kappaB, and can also downregulate the WNT/beta-catenin pathway. PPAR gamma and canonical WNT/beta-catenin pathway act in an opposite manner. PPAR gamma agonists appear as a promising treatment for the inhibition of demyelination and the promotion of proper remyelination through the control of both NF-kappaB activity and canonical WNT/beta-catenin pathway.

A normalisation for the four - detector system for gamma - gamma angular correlation studies

International Nuclear Information System (INIS)

Kiang, G.C.; Chen, C.H.; Niu, W.F.

1994-01-01

A normalisation method for the multiple - HPGe - detector system is described. The system consists of four coaxial HPGe detectors with a CAMAC event - by - event data acquisition system, enabling to measure six gamma -gamma coincidences of angles simultaneously. An application for gamma - gamma correlation studies of Kr 82 is presented and discussed. 3 figs., 6 refs. (author)

Use of gamma spectroscopy in activation analysis; Utilisation de la spectrographie gamma dans l'analyse par activation

Energy Technology Data Exchange (ETDEWEB)

Leveque, [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

1959-07-01

Brief review of the principles of activation analysis: calculation of activities, decay curves, {beta} absorption curves, examples of application. - Principle and description of the {gamma} spectrograph. - Practical utilisation of the {gamma} spectrograph: analysis by activation, analysis by {beta} - x fluorescence. - Sensitivity limit of the method and precision of the measurements. - Possible improvements to the method: {gamma} spectroscopy with elimination of the Compton effect. (author) [French] Bref rappel des principes de l'analyse par activation: calcul des activites, courbes de decroissance, courbes d'absorption {beta}, exemples d'utilisation. - Principe et description du spectrographe {gamma}. - Utilisation pratique de la spectrographie {gamma}: analyse par activation, analyse par fluorescence {beta} - x. - Limite de sensibilite de la methode et precision des mesures. - Ameliorations possibles de la methode: spectrographe {gamma} avec elimination de l'effet Compton. (auteur)

LHCb: $2\\beta_s$ measurement at LHCb

CERN Multimedia

Conti, G

2009-01-01

A measurement of $2\\beta_s$, the phase of the $B_s-\\bar{B_s}$ oscillation amplitude with respect to that of the ${\\rm b} \\rightarrow {\\rm c^{+}}{\\rm W^{-}}$ tree decay amplitude, is one of the key goals of the LHCb experiment with first data. In the Standard Model (SM), $2\\beta_s$ is predicted to be $0.0360^{+0.0020}_{-0.0016} \\rm rad$. The current constraints from the Tevatron are: $2\\beta_{s}\\in[0.32 ; 2.82]$ at 68$\\%$CL from the CDF experiment and $2\\beta_{s}=0.57^{+0.24}_{-0.30}$ from the D$\\oslash$ experiment. Although the statistical uncertainties are large, these results hint at the possible contribution of New Physics in the $B_s-\\bar{B_s}$ box diagram. After one year of data taking at LHCb at an average luminosity of $\\mathcal{L}\\sim2\\cdot10^{32}\\rm cm^{-2} \\rm s^{-1}$ (integrated luminosity $\\mathcal{L}_{\\rm int}\\sim 2 \\rm fb^{-1}$), the expected statistical uncertainty on the measurement is $\\sigma(2\\beta_s)\\simeq 0.03$. This uncertainty is similar to the $2\\beta_s$ value predicted by the SM.

Quantifying radionuclide signatures from a γ–γ coincidence system

International Nuclear Information System (INIS)

Britton, Richard; Jackson, Mark J.; Davies, Ashley V.

2015-01-01

A method for quantifying gamma coincidence signatures has been developed, and tested in conjunction with a high-efficiency multi-detector system to quickly identify trace amounts of radioactive material. The γ–γ system utilises fully digital electronics and list-mode acquisition to time–stamp each event, allowing coincidence matrices to be easily produced alongside typical ‘singles’ spectra. To quantify the coincidence signatures a software package has been developed to calculate efficiency and cascade summing corrected branching ratios. This utilises ENSDF records as an input, and can be fully automated, allowing the user to quickly and easily create/update a coincidence library that contains all possible γ and conversion electron cascades, associated cascade emission probabilities, and true-coincidence summing corrected γ cascade detection probabilities. It is also fully searchable by energy, nuclide, coincidence pair, γ multiplicity, cascade probability and half-life of the cascade. The probabilities calculated were tested using measurements performed on the γ–γ system, and found to provide accurate results for the nuclides investigated. Given the flexibility of the method, (it only relies on evaluated nuclear data, and accurate efficiency characterisations), the software can now be utilised for a variety of systems, quickly and easily calculating coincidence signature probabilities. - Highlights: • Monte-Carlo based software developed to easily create/update a coincidence signal library for environmental radionuclides. • Coincidence library utilised to accurately quantify gamma coincidence signatures. • All coincidence signature probabilities are corrected for cascade summing, conversion electron emission and pair production. • Key CTBTO relevant radionuclides have been tested to verify the calculated correction factors. • Accurately quantifying coincidence signals during routine analysis will allow dramatically improved detection

Data acquisition and processing system for coincidence measurements

International Nuclear Information System (INIS)

Li Xu

1990-07-01

An instrument has been designed for the absolute measurement of radioactivity with 4πβ(PC)-γ coincidence. The instrument can be used as a standard device for the radioactivity measurement in metrology laboratories. Also it can be used in the nuclear science and engineering research for absolute measurement of nuclear decay rate. The control of the system dead time and coincidence resolving time is digitized. The precision can reach ±2 ns. For data acquisition and communication the normalizing GPIB interface system technique is adopted. The measuring error caused by this instrument itself can be better than ±0.02%

Method of fission product beta spectra measurements for predicting reactor anti-neutrino emission

Energy Technology Data Exchange (ETDEWEB)

Asner, D.M.; Burns, K.; Campbell, L.W.; Greenfield, B.; Kos, M.S., E-mail: markskos@gmail.com; Orrell, J.L.; Schram, M.; VanDevender, B.; Wood, L.S.; Wootan, D.W.

2015-03-11

The nuclear fission process that occurs in the core of nuclear reactors results in unstable, neutron-rich fission products that subsequently beta decay and emit electron antineutrinos. These reactor neutrinos have served neutrino physics research from the initial discovery of the neutrino to today's precision measurements of neutrino mixing angles. The prediction of the absolute flux and energy spectrum of the emitted reactor neutrinos hinges upon a series of seminal papers based on measurements performed in the 1970s and 1980s. The steadily improving reactor neutrino measurement techniques and recent reconsiderations of the agreement between the predicted and observed reactor neutrino flux motivates revisiting the underlying beta spectra measurements. A method is proposed to use an accelerator proton beam delivered to an engineered target to yield a neutron field tailored to reproduce the neutron energy spectrum present in the core of an operating nuclear reactor. Foils of the primary reactor fissionable isotopes placed in this tailored neutron flux will ultimately emit beta particles from the resultant fission products. Measurement of these beta particles in a time projection chamber with a perpendicular magnetic field provides a distinctive set of systematic considerations for comparison to the original seminal beta spectra measurements. Ancillary measurements such as gamma-ray emission and post-irradiation radiochemical analysis will further constrain the absolute normalization of beta emissions per fission. The requirements for unfolding the beta spectra measured with this method into a predicted reactor neutrino spectrum are explored.

Standardization of Ga-68 by coincidence measurements, liquid scintillation counting and 4πγ counting.

Science.gov (United States)

Roteta, Miguel; Peyres, Virginia; Rodríguez Barquero, Leonor; García-Toraño, Eduardo; Arenillas, Pablo; Balpardo, Christian; Rodrígues, Darío; Llovera, Roberto

2012-09-01

The radionuclide (68)Ga is one of the few positron emitters that can be prepared in-house without the use of a cyclotron. It disintegrates to the ground state of (68)Zn partially by positron emission (89.1%) with a maximum energy of 1899.1 keV, and partially by electron capture (10.9%). This nuclide has been standardized in the frame of a cooperation project between the Radionuclide Metrology laboratories from CIEMAT (Spain) and CNEA (Argentina). Measurements involved several techniques: 4πβ-γ coincidences, integral gamma counting and Liquid Scintillation Counting using the triple to double coincidence ratio and the CIEMAT/NIST methods. Given the short half-life of the radionuclide assayed, a direct comparison between results from both laboratories was excluded and a comparison of experimental efficiencies of similar NaI detectors was used instead. Copyright © 2012 Elsevier Ltd. All rights reserved.

Effects of beta/gamma radiation on nuclear waste glasses

Energy Technology Data Exchange (ETDEWEB)

Weber, W.J. [Pacific Northwest National Lab., Richland, WA (United States)

1997-07-01

A key challenge in the disposal of high-level nuclear waste (HLW) in glass waste forms is the development of models of long-term performance based on sound scientific understanding of relevant phenomena. Beta decay of fission products is one source of radiation that can impact the performance of HLW glasses through the interactions of the emitted {beta}-particles and g-rays with the atoms in the glass by ionization processes. Fused silica, alkali silicate glasses, alkali borosilicate glasses, and nuclear waste glasses are all susceptible to radiation effects from ionization. In simple glasses, defects (e.g., non-bridging oxygen and interstitial molecular oxygen) are observed experimentally. In more complex glasses, including nuclear waste glasses, similar defects are expected, and changes in microstructure, such as the formation of bubbles, have been reported. The current state of knowledge regarding the effects of {beta}/{gamma} radiation on the properties and microstructure of nuclear waste glasses are reviewed. (author)

Measurements of the background noise gamma at the Modane underground laboratory

International Nuclear Information System (INIS)

Morales, A.; Morales, J.; Nunez-Lagos, R.; Villar, J.A.

1985-01-01

Experimental measurements of the background have been performed at the Modane underground laboratory, in the Frejus tunnel, in order to locate here a neutrinoless double beta decay on 76 Ge experiment. The background reduction relative to the sea level laboratory at Bordeaux is studied, as well as the intrinsic radiactivity the INa and F 2 Ba scintillators to be selected as a 4 coincidence crown for the experiment. (author)

Beta-and gamma-turns in proteins revisited: a new set of amino acid turn-type dependent positional preferences and potentials.

Science.gov (United States)

Guruprasad, K; Rajkumar, S

2000-06-01

The number of beta-turns in a representative set of 426 protein three-dimensional crystal structures selected from the recent Protein Data Bank has nearly doubled and the number of gamma-turns in a representative set of 320 proteins has increased over seven times since the previous analysis. Beta-turns (7153) and gamma-turns (911) extracted from these proteins were used to derive a revised set of type-dependent amino acid positional preferences and potentials. Compared with previous results, the preference for proline, methionine and tryptophan has increased and the preference for glutamine, valine, glutamic acid and alanine has decreased for beta-turns. Certain new amino acid preferences were observed for both turn types and individual amino acids showed turn-type dependent positional preferences. The rationale for new amino acid preferences are discussed in the light of hydrogen bonds and other interactions involving the turns. Where main-chain hydrogen bonds of the type NH(i + 3) --> CO(i) were not observed for some beta-turns, other main-chain hydrogen bonds or solvent interactions were observed that possibly stabilize such beta-turns. A number of unexpected isolated beta-turns with proline at i + 2 position were also observed. The NH(i + 2) --> CO(i) hydrogen bond was observed for almost all gamma-turns. Nearly 20% classic gamma-turns and 43% inverse gamma-turns are isolated turns.

Assessment of the geometric coincidence of neutron and gamma probe measurements with solo 40 and CPN 501 B

International Nuclear Information System (INIS)

Valles, V.; Guiresse, M.; Tcherbakov, R.

1989-01-01

The distance between the gamma and neutron probe measurement centres was determined for the Nardeux Solo 40 and CPN 501 B probes. The centre of the spheres of influence was localized using a water-air interface constituted by a metal cylinder filled with 200 liters of water. For Solo 40, the discrepancy between the two measurement centres was 6 cm. This shift value, which is quite acceptable, does not require any correction for these measurements, even when the soil is heterogeneous. For CNP 501 B, the discrepancy between the neutron and gamma measurement was 11 cm, i.e. nearly twice the value observed with Solo 40. In soils with a marked vertical heterogeneity, it therefore seems preferable to operate a 11 cm shift of the probe between the moisture and density measurements [fr

Period concatenation underlies interactions between gamma and beta rhythms in neocortex

Directory of Open Access Journals (Sweden)

Anita K Roopun

2008-04-01

Full Text Available The neocortex generates rhythmic electrical activity over a frequency range covering many decades. Specific cognitive and motor states are associated with oscillations in discrete frequency bands within this range, but it is not known whether interactions and transitions between distinct frequencies are of functional importance. When coexpressed rhythms have frequencies that differ by a factor of two or more interactions can be seen in terms of phase synchronization. Larger frequency differences can result in interactions in the form of nesting of faster frequencies within slower ones by a process of amplitude modulation. It is not known how coexpressed rhythms, whose frequencies differ by less than a factor of two may interact. Here we show that two frequencies (gamma – 40 Hz and beta2 – 25 Hz, coexpressed in superficial and deep cortical laminae with low temporal interaction, can combine to generate a third frequency (beta1 – 15 Hz showing strong temporal interaction. The process occurs via period concatenation, with basic rhythm-generating microcircuits underlying gamma and beta2 rhythms forming the building blocks of the beta1 rhythm by a process of addition. The mean ratio of adjacent frequency components was a constant – approximately the golden mean – which served to both minimize temporal interactions, and permit multiple transitions, between frequencies. The resulting temporal landscape may provide a framework for multiplexing – parallel information processing on multiple temporal scales.

On k-Gamma and k-Beta Distributions and Moment Generating Functions

Directory of Open Access Journals (Sweden)

Gauhar Rahman

2014-01-01

Full Text Available The main objective of the present paper is to define k-gamma and k-beta distributions and moments generating function for the said distributions in terms of a new parameter k>0. Also, the authors prove some properties of these newly defined distributions.

The p110beta isoform of phosphoinositide 3-kinase signals downstream of G protein-coupled receptors and is functionally redundant with p110gamma.

Science.gov (United States)

Guillermet-Guibert, Julie; Bjorklof, Katja; Salpekar, Ashreena; Gonella, Cristiano; Ramadani, Faruk; Bilancio, Antonio; Meek, Stephen; Smith, Andrew J H; Okkenhaug, Klaus; Vanhaesebroeck, Bart

2008-06-17

The p110 isoforms of phosphoinositide 3-kinase (PI3K) are acutely regulated by extracellular stimuli. The class IA PI3K catalytic subunits (p110alpha, p110beta, and p110delta) occur in complex with a Src homology 2 (SH2) domain-containing p85 regulatory subunit, which has been shown to link p110alpha and p110delta to Tyr kinase signaling pathways. The p84/p101 regulatory subunits of the p110gamma class IB PI3K lack SH2 domains and instead couple p110gamma to G protein-coupled receptors (GPCRs). Here, we show, using small-molecule inhibitors with selectivity for p110beta and cells derived from a p110beta-deficient mouse line, that p110beta is not a major effector of Tyr kinase signaling but couples to GPCRs. In macrophages, both p110beta and p110gamma contributed to Akt activation induced by the GPCR agonist complement 5a, but not by the Tyr kinase ligand colony-stimulating factor-1. In fibroblasts, which express p110beta but not p110gamma, p110beta mediated Akt activation by the GPCR ligands stromal cell-derived factor, sphingosine-1-phosphate, and lysophosphatidic acid but not by the Tyr kinase ligands PDGF, insulin, and insulin-like growth factor 1. Introduction of p110gamma in these cells reduced the contribution of p110beta to GPCR signaling. Taken together, these data show that p110beta and p110gamma can couple redundantly to the same GPCR agonists. p110beta, which shows a much broader tissue distribution than the leukocyte-restricted p110gamma, could thus provide a conduit for GPCR-linked PI3K signaling in the many cell types where p110gamma expression is low or absent.

Properties of low-lying intruder states in $^{34}$Al and $^{34}$Si sequentially populated in $\\beta$-decay of $^{34}$Mg

CERN Multimedia

A low-lying long-lived (26±1 ms) isomer in $^{34}$Al has been observed recently and assigned as 1$^{+}$ state of intruder character. It was populated in $^{36}$S fragmentation and feeds, in $\\beta$-decay, the 0$_{2}^{+}$ state in $^{34}$Si whose excitation energy and lifetime were determined in an electron-positron pairs spectroscopy experiment. In the present experiment we intend to measure for the first time the $\\gamma$-rays following the $\\beta$-decay of $^{34}$Mg. Despite the interest for $^{34}$Mg, the up-right corner of the “N$\\thicksim$20 island of inversion”, the only information on its $\\beta$-decay is the lifetime of 20±10 ms, determined from $\\beta$-neutron coincidences. As a result of the proposed experiment, we expect to place the first transitions in the level scheme of $^{34}$Al and to strongly populate the newly observed isomer, measuring its excitation energy, if the branching ratio to 4$^{−}$ ground state is significant. Theoretical estimations for the $\\beta$-decay of the new isome...

Beta decay of the fission product 125Sb and a new complete evaluation of absolute gamma ray transition intensities

Science.gov (United States)

Rajput, M. U.; Ali, N.; Hussain, S.; Mujahid, S. A.; MacMahon, D.

2012-04-01

The radionuclide 125Sb is a long-lived fission product, which decays to 125Te by negative beta emission with a half-life of 1008 day. The beta decay is followed by the emission of several gamma radiations, ranging from low to medium energy, that can suitably be used for high-resolution detector calibrations, decay heat calculations and in many other applications. In this work, the beta decay of 125Sb has been studied in detail. The complete published experimental data of relative gamma ray intensities in the beta decay of the radionuclide 125Sb has been compiled. The consistency analysis was performed and discrepancies found at several gamma ray energies. Evaluation of the discrepant data was carried out using Normalized Residual and RAJEVAL methods. The decay scheme balance was carried out using beta branching ratios, internal conversion coefficients, populating and depopulating gamma transitions to 125Te levels. The work has resulted in the consistent conversion factor equal to 29.59(13) %, and determined a new evaluated set of the absolute gamma ray emission probabilities. The work has also shown 22.99% of the delayed intensity fraction as outgoing from the 58 d isomeric 144 keV energy level and 77.01% of the prompt intensity fraction reaching to the ground state from the other excited states. The results are discussed and compared with previous evaluations. The present work includes additional experimental data sets which were not included in the previous evaluations. A new set of recommended relative and absolute gamma ray emission probabilities is presented.

Beta decay of the fission product 125Sb and a new complete evaluation of absolute gamma ray transition intensities

International Nuclear Information System (INIS)

Rajput, M.U.; Ali, N.; Hussain, S.; Mujahid, S.A.; MacMahon, D.

2012-01-01

The radionuclide 125 Sb is a long-lived fission product, which decays to 125 Te by negative beta emission with a half-life of 1008 day. The beta decay is followed by the emission of several gamma radiations, ranging from low to medium energy, that can suitably be used for high-resolution detector calibrations, decay heat calculations and in many other applications. In this work, the beta decay of 125 Sb has been studied in detail. The complete published experimental data of relative gamma ray intensities in the beta decay of the radionuclide 125 Sb has been compiled. The consistency analysis was performed and discrepancies found at several gamma ray energies. Evaluation of the discrepant data was carried out using Normalized Residual and RAJEVAL methods. The decay scheme balance was carried out using beta branching ratios, internal conversion coefficients, populating and depopulating gamma transitions to 125 Te levels. The work has resulted in the consistent conversion factor equal to 29.59(13) %, and determined a new evaluated set of the absolute gamma ray emission probabilities. The work has also shown 22.99% of the delayed intensity fraction as outgoing from the 58 d isomeric 144 keV energy level and 77.01% of the prompt intensity fraction reaching to the ground state from the other excited states. The results are discussed and compared with previous evaluations. The present work includes additional experimental data sets which were not included in the previous evaluations. A new set of recommended relative and absolute gamma ray emission probabilities is presented.

Screening procedures for alpha, beta and gamma emitting radionuclides in urine

International Nuclear Information System (INIS)

Kramer, G.H.; Gardner, S.E.; Johnson, J.R.

1983-08-01

The gross actinide and beta screening methods currently used by the Bioassay Laboratory at Chalk River Nuclear Laboratories have been documented and tested. The gross gamma method has also been documented. The gross actinide method was tested with Th-nat, Pu-239, Np-237, Am-241 and Cm-244 and the average percent recoveries were 90, 99, 45, 72 and 78, respectively. The gross beta method was tested with Sr-90/Y-90, Ce-144/Pr-144, Pm-147 and Ba-133 and the average percent recoveries were 78, 100, 46 and 46, respectively. Detection limits for the gross actinide (alpha) method are found to be about 0.4 mBq and about 39 mBq for the gross beta method

Calibration and adjustment of the EGRET coincidence/time-of-flight system

International Nuclear Information System (INIS)

Hunter, S.D.

1991-01-01

The coincidence/time-of-flight system of the energetic gamma ray experiment telescope (EGRET) on NASA's Gamma Ray Observatory (GRO) consists of two layers of sixteen scintillator tiles. These tiles are paired into 96 coincidence telescopes. Valid coincidence and time-of-flight values (indicating downward moving particles) from one of these telescopes are two of the requirements for an EGRET event trigger. To maximize up-down discrimination, variations in the mean timing value of the telescopes must be minimized. The timing values of the 96 telescopes are not independent, hence they cannot be individually adjusted to calibrate the system. An iterative approach was devised to determine adjustments to the length of the photomultiplier signal cables. These adjustments were made directly in units of time using a time domain reflectometry technique, by timing the reflection of a fast pulse from the unterminated end of eable, and observing the charge in signal propagation time as the length of the cable was shortened. Two constant fraction discriminators, a time-to-amplitude converter and a pulse height analyzer were used for these measurements. Using this direct time measuring approach, the timing values for the 96 EGRET coincidence/time-of-flight telescopes were adjusted with an FWHM variation of less than 450 ps (± 1 TOF timing channel). (orig.)

Modeling dynamic beta-gamma polymorphic transition in Tin

Science.gov (United States)

Chauvin, Camille; Montheillet, Frank; Petit, Jacques; CEA Gramat Collaboration; EMSE Collaboration

2015-06-01

Solid-solid phase transitions in metals have been studied by shock waves techniques for many decades. Recent experiments have investigated the transition during isentropic compression experiments and shock-wave compression and have highlighted the strong influence of the loading rate on the transition. Complementary data obtained with velocity and temperature measurements around the polymorphic transition beta-gamma of Tin on gas gun experiments have displayed the importance of the kinetics of the transition. But, even though this phenomenon is known, modeling the kinetic remains complex and based on empirical formulations. A multiphase EOS is available in our 1D Lagrangian code Unidim. We propose to present the influence of various kinetic laws (either empirical or involving nucleation and growth mechanisms) and their parameters (Gibbs free energy, temperature, pressure) on the transformation rate. We compare experimental and calculated velocities and temperature profiles and we underline the effects of the empirical parameters of these models.

Beta decay and magnetic moments as tools to probe nuclear structure. Study of neutron-rich nuclei around N=40; Decroissance beta et moments magnetiques comme outils pour sonder la structure nucleaire. Etude des noyaux riches en neutrons autour de N=40

Energy Technology Data Exchange (ETDEWEB)

Matea, I

2003-12-01

The evolution of nuclear structure in nuclei far from the {beta} stability line is one of the 'hot topics' in modern experimental and theoretical nuclear physics. The present thesis is devoted to the study of structure of neutron-rich nuclei around N=40. The evolution of the neutron g9/2 orbital with increasing number of neutrons is one of the key points defining the structure of these nuclei at low excitation energy. We used for this investigation as experimental tools the magnetic dipole moments measurements and the {beta} decay spectroscopy. For the measurement of the gyromagnetic factor of the 9/2{sup +} isomeric state in Fe{sup 61} we have applied the TDPAD method. This method (like most of measurements of nuclear moments) requires an oriented ensemble of nuclei. The orientation of Fe{sup 61m} was achieved via the fragmentation of Ni{sup 64} at 55 MeV/u and the selection of the fragment momentum with the LISE spectrometer at GANIL. The experimental device was specially conceived to preserve the alignment up to the implantation point. The measured value of the g factor was compared with large-scale shell model and Hartree-Fock-Bogoliubov model predictions. The nuclei studied via {beta} decay were produced by the fragmentation of Kr{sup 86} at 58 MeV/u. For the selection of reaction products we used for the first time the LISE2000 spectrometer and for the detection of {gamma} rays four EXOGAM clover detectors. We measured 5 new lifetimes and 4 lifetimes with a higher precision. From the prompt {beta}{gamma} coincidences we identified new states in the daughter nuclei, as it is the case of the first 2{sup +} excited states in Fe{sup 68} and Ni{sup 72}. The results were compared with the predictions of the large-scale shell model. Other transitions were observed for the first time in {beta}{gamma} decay of Ti{sup 60}, Fe{sup 70} and Co{sup 71,73}. (author)

Use of proportional gas scintillator in absolute measurements of alpha-gamma emitter activities

International Nuclear Information System (INIS)

Tobias, C.C.B.

1987-01-01

The absolute activity of U-235 contained in a U 3 O 8 sample was measured utilizing a sum-coincidence circuit which selects only the alpha particles which are simultaneous with the 143 KeV and 186 KeV gamma radiations from the Th-231 (product nucleus). The alpha particles were detected by means of a new type of a gas scintillating chamber, in which the light emitted by excitation of the gas atoms, due to the passage of a charged incoming particle, has its intensity increased by the action of an applied electric field. The gamma radiations were detected by means of a NaI(Tl) 1'' x 1 1/2'' scintillation detector. The value obtained for the half-life of U-235 was compared with the data available from various observers which used different experimental techniques. It is shown tht the results, are in excellent agreement with the best international data available on the subject and that, therefore, the sum-coincidence technique constitutes an important method for such measurements. (Author) [pt

Comparative study of chance coincidence correction in measuring 223Ra and 224Ra by delay coincidence method

International Nuclear Information System (INIS)

Yan Yongjun; Huang Derong; Zhou Jianliang; Qiu Shoukang

2013-01-01

The delay coincidence measurement of 220 Rn and 219 Rn has been proved to be a valid indirect method for measuring 224 Ra and 223 Ra extracted from natural water, which can provide valuable information on estuarine/ocean mixing, submarine groundwater discharge, and water/soil interactions. In practical operation chance coincidence correction must be considered, mostly Moore's correction method, but Moore's and Giffin's methods were incomplete in some ways. In this paper the modification (method 1) and a new chance coincidence correction formula (method 2) were provided. Experiments results are presented to demonstrate the conclusions. The results show that precision is improved while counting rate is less than 70 min- 1 . (authors)

Secondary electron/reflected particle coincidence studies during slow highly charged ion-surface interactions

Energy Technology Data Exchange (ETDEWEB)

McGrath, C.T.; Szilagyi, Z.; Shah, M.B.; McCullough, R.W. [Queen' s Univ., Belfast, Northern Ireland (United Kingdom); Woolsey, J.M. [Stirling Univ. (United Kingdom). DBMS; Trassl, R.; Salzborn, E. [Giessen Univ. (Germany). Inst. fuer Kernphysik

2001-07-01

We have measured the secondary electron emission statistics (ES) for 5 keV N{sup q+} (q = 1-4) ions incident at 10 on polycrystalline aluminium, in coincidence with specularly reflected N{sup 0}. In this arrangement the kinetic contribution to secondary electron emission is minimised. The experimental data shows that the coincident electron yield, {gamma}, increases linearly with incident ion charge state. The kinetic emission contribution has also been determined from this data. The ES due to 2 and 4 keV He{sup 2+} impact on polycrystalline aluminium in coincidence with specularly reflected He{sup +} and He{sup 0} have also been determined. The process He{sup 2+} {yields} He{sup 0} yields a larger {gamma} value than the process He{sup 2+} {yields} He{sup +}. (orig.)

GammaWorkshops Proceedings

DEFF Research Database (Denmark)

Strålberg, Elisabeth; Klemola, Seppo; Nielsen, Sven Poul

to the GammaWorkshops. The topics included efficiency transfer, true coincidence summing corrections, self-attenuation corrections, measurement of natural radionuclides (natural decay series), combined measurement uncertainty calculations, and detection limits. These topics covered both lectures and practical...

A beta ray spectrometer based on a two-, or three-element silicon detector coincidence telescope

International Nuclear Information System (INIS)

Horowitz, Y.S.; Weizman, Y.; Hirning, C.R.

1995-01-01

The operation of a beta ray energy spectrometer based on a two-or three-element silicon detector telescope is described. The front detector (A) is a thin, totally depleted, silicon surface barrier detector either 40 μm, 72 μm or 98 μm thick. The back detector (C) is a Li compensated silicon detector, 5000 μm thick. An additional thin detector can be inserted between these two detectors when additional photon rejection capability is required in intense photon fields. The capability of the spectrometer to reject photons is based on the fact that incident photons will have a small probability of simultaneously losing detectable energy in two detectors and an even smaller probability of losing detectable energy in all three detectors. Electrons, however, above a low energy threshold, will always record simultaneous, events in all three detectors. The spectrometer is capable of measuring electron energies from a lower energy coincidence threshold of 70 keV with 60% efficiency increasing to 100% efficiency in the energy region between 150 keV and 2.5 MeV. (Author)

A scintillation detector for measuring inert gas beta rays

International Nuclear Information System (INIS)

Shi Hengchang; Yu Yunchang

1989-10-01

The inert gas beta ray scintillation detector, which is made of organic high polymers as the base and coated with compact fluorescence materials, is a lower energy scintillation detector. It can be used in the nuclear power plant and radioactive fields as a lower energy monitor to detect inert gas beta rays. Under the conditions of time constant 10 minutes, confidence level is 99.7% (3σ), the intensity of gamma rays 2.6 x 10 -7 C/kg ( 60 Co), and the minimum detectable concentration (MDC) of this detector for 133 Xe 1.2 Bq/L. The measuring range for 133 Xe is 11.1 ∼ 3.7 x 10 4 Bq/L. After a special measure is taken, the device is able to withstand 3 x 10 5 Pa gauge pressure. In the loss-of-cooolant-accident, it can prevent the radioactive gas of the detector from leaking. This detector is easier to be manufactured and decontaminated

Proceedings of the International Symposium Advances in alpha, Beta- and Gamma-Ray spectrometry

International Nuclear Information System (INIS)

1997-01-01

The International Committee for Radionuclide Metrology (ICRM) is an association of radionuclide metrology laboratories whose membership is composed of delegates of these laboratories together with other scientists actively engaged in the study and applications of radioactivity. The scientific activities are carried out in the frame of six Working Groups. Two of them, the Alpha-Particle Spectrometry and the Gamma-and Beta-ray Spectrometry Working Groups held a common workshop in Pushkin, St. Petersburg, 18 to 20 September 1996, under the title Advances in Alpha-Beta-and Gamma-Ray Sepectrometry, at the kind invitation of the D.I. Mendeleyev Institute for Metrology. More than 30 people from 14 laboratories attended the meeting, and nineteen oral communications were presented, from which twelve were retained for publication an are included in these proceedings. (Author)

Beta-gamma contaminated solid waste incinerator facility

International Nuclear Information System (INIS)

Hootman, H.E.

1979-10-01

This technical data summary outlines a reference process to provide a 2-stage, 400 lb/hour incinerator to reduce the storage volume of combustible process waste contaminated with low-level beta-gamma emitters in response to DOE Manual 0511. This waste, amounting to more than 200,000 ft 3 per year, is presently buried in trenches in the burial ground. The anticipated storage volume reduction from incineration will be a factor of 20. The incinerator will also dispose of 150,000 gallons of degraded solvent from the chemical separations areas and 5000 gallons per year of miscellaneous nonradioactive solvents which are presently being drummed for storage

Study of radiation detectors response in standard X, gamma and beta radiation standard beams; Estudo da resposta de monitores de radioprotecao em feixes padronizados de radiacao X, gama e beta

Energy Technology Data Exchange (ETDEWEB)

Nonato, Fernanda Beatrice Conceicao

2010-07-01

The response of 76 Geiger-Mueller detectors, 4 semiconductor detectors and 34 ionization chambers were studied. Many of them were calibrated with gamma radiation beams ({sup 37}Cs and {sup 60}Co), and some of them were tested in beta radiation ({sup 90}Sr+{sup 9'}0Y e {sup 204}Tl) and X radiation (N-60, N-80, N-100, N-150) beams. For all three types of radiation, the calibration factors of the instruments were obtained, and the energy and angular dependences were studied. For beta and gamma radiation, the angular dependence was studied for incident radiation angles of 0 deg and +- 45 deg. The curves of the response of the instruments were obtained over an angle interval of 0 deg to +- 90 deg, for gamma, beta and X radiations. The calibration factors obtained for beta radiation were compared to those obtained for gamma radiation. For gamma radiation, 24 of the 66 tested Geiger-Mueller detectors presented results for the energy dependence according to international recommendation of ISO 4037-2 and 56 were in accordance with the Brazilian ABNT 10011 recommendation. The ionization chambers and semiconductors were in accordance to national and international recommendations. All instruments showed angular dependence less than 40%. For beta radiation, the instruments showed unsatisfactory results for the energy dependence and angular dependence. For X radiation, the ionization chambers presented results for energy dependence according to the national recommendation, and the angular dependence was less than 40%. (author)

Study of radiation detectors response in standard X, gamma and beta radiation standard beams; Estudo da resposta de monitores de radioprotecao em feixes padronizados de radiacao X, gama e beta

Energy Technology Data Exchange (ETDEWEB)

Nonato, Fernanda Beatrice Conceicao

2010-07-01

The response of 76 Geiger-Mueller detectors, 4 semiconductor detectors and 34 ionization chambers were studied. Many of them were calibrated with gamma radiation beams ({sup 37}Cs and {sup 60}Co), and some of them were tested in beta radiation ({sup 90}Sr+{sup 9'}0Y e {sup 204}Tl) and X radiation (N-60, N-80, N-100, N-150) beams. For all three types of radiation, the calibration factors of the instruments were obtained, and the energy and angular dependences were studied. For beta and gamma radiation, the angular dependence was studied for incident radiation angles of 0 deg and +- 45 deg. The curves of the response of the instruments were obtained over an angle interval of 0 deg to +- 90 deg, for gamma, beta and X radiations. The calibration factors obtained for beta radiation were compared to those obtained for gamma radiation. For gamma radiation, 24 of the 66 tested Geiger-Mueller detectors presented results for the energy dependence according to international recommendation of ISO 4037-2 and 56 were in accordance with the Brazilian ABNT 10011 recommendation. The ionization chambers and semiconductors were in accordance to national and international recommendations. All instruments showed angular dependence less than 40%. For beta radiation, the instruments showed unsatisfactory results for the energy dependence and angular dependence. For X radiation, the ionization chambers presented results for energy dependence according to the national recommendation, and the angular dependence was less than 40%. (author)

Photoion Auger-electron coincidence measurements near threshold

International Nuclear Information System (INIS)

Levin, J.C.; Biedermann, C.; Keller, N.; Liljeby, L.; Short, R.T.; Sellin, I.A.; Lindle, D.W.

1990-01-01

The vacancy cascade which fills an atomic inner-shell hole is a complex process which can proceed by a variety of paths, often resulting in a broad distribution of photoion charge states. We have measured simplified argon photoion charge distributions by requiring a coincidence with a K-LL or K-LM Auger electron, following K excitation with synchrotron radiation, as a function of photon energy, and report here in detail the argon charge distributions coincident with K-L 1 L 23 Auger electrons. The distributions exhibit a much more pronounced photon-energy dependence than do the more complicated non-coincident spectra. Resonant excitation of the K electron to np levels, shakeoff of these np electrons by subsequent decay processes, double-Auger decay, and recapture of the K photoelectron through postcollision interaction occur with significant probability. 17 refs

A flexible VME-based multiparametric apparatus for coincidence spectroscopy and investigation of parameters of detectors

International Nuclear Information System (INIS)

Jakubek, J.

2000-01-01

The methodology of Coincidence Instrumental Activation Analysis (CIAA) based on a three-parameter gamma-gamma coincidence spectrometer with two high-purity Ge detectors is presented. A flexible coincidence system was built on standard NIM spectrometric modules connected to a VME or CAMAC data acquisition system. The detailed setup of the system optimized for the maximum energy resolution, maximum data throughput (dead time correction, pile-up rejection) and maximum flexibility is described. The use of different data acquisition platforms is discussed (VME bus with several different controllers, CAMAC bus). The software developed for reading and basic processing of measured data is also described. The possibilities of off-line data evaluation are discussed. The system was tested with respect to its compliance with the criteria of the CIAA method. Some results of measurement by this method are also presented. The flexibility of the system is demonstrated on its ability to measure the time characteristics of different detectors. (author)

Change in the aldolase activity in rats' hearts after irradiation with. gamma. and. beta. rays

Energy Technology Data Exchange (ETDEWEB)

Kukulyanskaya, M F; Borodina, G N

1973-01-01

The activity of aldolase fructoso-1-phosphate (I) and aldolase fructoso-1, 6-diphosphate (II) has been studied at various periods after total ..gamma.. and ..beta.. irradiation of rats at a dose of 42 rads. It has been shown that after ..gamma.. irradiation the activity of I increases in the supernatant liquid of the heart muscle homogenate, but drops sharply in the nuclei. In total, the activity of the homogenate did not change. The activity of II dropped for seven days, and after 1 hour and 30 days it was above the normal level. After ..beta.. radiation the activity of II is slowed down after 1, 7, and 15 days. These changes occur in all subcellular fractions. The authors note that the changes in the activity of aldolases are more sharply demarcated after ..gamma.. irradiation and are more substantial for II. (JPRS)

Study of 193Os beta- decay

International Nuclear Information System (INIS)

Zahn, Guilherme Soares

2006-01-01

In this work, the excited levels of 193 Ir populated by the beta - decay of 193 Os (T 1/2 ∼ 30h) were investigated. For that purpose, ∼ 5 mg samples of 99%-enriched 192 Os were irradiated under a thermal neutron flux of ∼ 10 12 s -1 and then analysed both using single gamma spectroscopy and a 4-detector multi parametric acquisition facility, which provided data for both a gamma gamma coincidence analysis and a directional angular correlation gamma gamma (θ ) study. From these data, 28 transitions were added to this decay scheme, 11 of which were previously known from nuclear reactions and 17 observed for the first time. Eight excited levels were also added to the decay scheme, 3 of which were known from nuclear reaction studies - the remaining 5 are suggested for the first time. Moreover, it was possible to confirm suspicions found in reference that the levels at 848.93 keV and 849.093 keV are indeed the same; it was also possible to confirm the existence of an excited level at 806.9 keV, which had been inferred, but not experimentally confirmed in beta decay studies to date. The angular correlation analysis allowed for the definition of the spin of the excited level at 874 keV as 5/2 +; moreover, the results showed a 79% probability that the spin of the 1078 keV level is 5/2/'-, and also restricted the spin possibilities for the new excited level at 960 keV to two values (1/2 or 3/2). It was also possible to measure the multipolarity mixing ratio (δ Ln+1 /L n ) for 43 transitions - 19 of them for the first time and most of the others with a better precision than previously known. Finally, an attempt was made to understand the low-lying levels structure for this nucleus using a theoretical model, which reproduced the ground state and the two lowest-lying excited levels in 193 Ir. (author)

Contribution have the survey of the transformation {sup 181}Hf {yields} {sup 181}Ta (17 {mu}s) {yields} {sup 181}Ta; Contribution a l'etude de la transformation {sup 181}Hf {yields} {sup 181}Ta (17 {mu}s) {yields} {sup 181}Ta

Energy Technology Data Exchange (ETDEWEB)

Baullini, R; Chaminade, R; Desneiges, P; Grjebine, T; Quidort, J; Wahl, R [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1953-07-01

The metastable state of Ta, whose period is around 20 microseconds, has been discovered by De BENEDETTI and Mc GOWAM who done measurements of deferred coincidences between the particles beta and the electrons of conversion given out by the hafnium radiated by thermal neutrons. We measured the period of {sup 181}Ta{sup *} by measures of deferred coincidences {beta}-e{sup -} and {beta}-{gamma}. A method of survey of the specter of photons amplitudes emitted by {sup 181}Ta{sup *} has been fit. This method permitted to solve the presence of {gamma} in the radiation emitted in synchronism with the deexcitation of {sup 181}Ta{sup *}. Finally in a last chapter, we propose a method of dosage of the {sup 181}Hf in presence of other radioelements. (M.B.) [French] L'etat metastable de Ta, dont la periode est voisine de 20 microsecondes, a ete decouvert par DE BENEDETTI et Mc GOWAM qui effectuaient des mesures de coincidences differees entre les particules beta et les electrons de conversion emis par du hafnium irradie par des neutrons thermiques. Nous avons mesure la periode de {sup 181}Ta{sup *} par des mesures de coincidences differees {beta}-e{sup -} et {beta}-{gamma}. Une methode d'etude du spectre d'amplitudes des photons emis par {sup 181}Ta{sup *} a ete mise au point. Cette methode a permis d'eclaircir la presence de {gamma} dans le rayonnement emis en synchronisme avec la desexcitation de {sup 181}Ta{sup *}. Enfin dans un dernier chapitre, on proposera une methode de dosage du {sup 181}Hf en presence d'autres radioelements. (M.B.)

Method for improvement of gamma-transition cascade spectra amplitude resolution by computer processing of coincidence codes

International Nuclear Information System (INIS)

Sukhovoj, A.M.; Khitrov, V.A.

1982-01-01

A method of improvement of amplitude resolution in the case of record of coinciding codes on the magnetic tape is suggested. It is shown on the record with Ge(Li) detectors of cascades of gamma-transitions from the 35 Cl(n, #betta#) reaction that total width at a half maximum of the peak may decrease by a factor of 2.6 for quanta with the energy similar to the neutron binding energy. Efficiency loss is absent

F-18 FDG PET with coincidence detection, dual-head gamma camera, initial experience in oncology

Energy Technology Data Exchange (ETDEWEB)

Chu, J.M.G.; Pocock, N.; Quach, T.; Camden, B.M.C. [Liverpool Health Services, Liverpool, NSW (Australia). Department of Nuclear Medicine and Clinical Ultrasound

1998-06-01

Full text: The development of Co-incidence Detection (CD) in gamma camera technology has allowed the use of positron radiopharmaceuticals in clinical practice without dedicated PET facilities. We report our initial experience of this technology in Oncological applications. All patients were administered 200 MBq of F- 18 FDG intravenously in a fasting state, with serum glucose below 8.9 mmol/L., and hydration well maintained. Tomography was performed using an ADAC Solus Molecular Co-incidence Detection (MCD) dual-head gamma camera, 60 minutes after administration and immediately after voiding. Tomography of the torso required up to three collections depending on the length of the patient, with each collection requiring 32 steps of 40 second duration, and a 50% overlap. Tomography of the brain required a single collection with 32 steps of 80 seconds. Patients were scanned in the supine position. An iterative reconstruction algorithm was employed without attenuation correction. All patients had histologically confirmed malignancy. Scan findings were correlated with results of all conventional diagnostic imaging procedures that were pertinent to the evaluation and management of each individual patient`s disease. Correlation with tumour type and treatment status was also undertaken. F-18 FDG uptake as demonstrated by CD-PET was increased in tumour bearing sites. The degree of increased uptake varied with tumour type and with treatment status. Our initial experience with CD-PET has been very encouraging, and has led us to undertake prospective short and long term studies to define its role in oncology

Beta-decay of {sup 56}Cu

Energy Technology Data Exchange (ETDEWEB)

Ramdhane, M.; Baumann, P.; Knipper, A.; Walter, G. [Institute de Recherches Subatomiques, 67 - Strasbourg (France); Janas, Z.; Plochocki, A. [Warsaw Univ. (Poland). Inst. of Experimental Physics; Aeystoe, J.; Dendooven, P.; Jokinen, A.; Oinonen, M.; Pentilae, H. [Jyvaeskylae Univ. (Finland); Liu, W.; Grawe, H.; Hu, Z.; Kirchner, R.; Klepper, O.; Roeckl, E. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany); Gorska, M. [Warsaw Univ. (Poland). Inst. of Experimental Physics]|[Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany); Fujita, Y. [Osaka Univ. (Japan); Brown, B.A. [Michigan State Univ., East Lansing, MI (United States)

1998-02-01

By measuring positrons and {beta}-delayed {gamma}-rays emitted from mass-separated sources, the decay of {sup 56}Cu(4{sup +},T{sub z}=-1,T=1) to states in the doubly-magic nucleus {sup 56}Ni was studied for the first time. The half-life of {sup 56}Cu was measured to be 78(15) ms, and four {beta}-delayed {gamma}-rays were assigned to its decay. The resulting experimental data on Fermi and Gamow-Teller strength are compared with shell-model predictions. (orig.)

Contribution to the study of {beta} disintegration and of nuclear structure using experiments on certain {beta}-{gamma} cascades: 198{sub Au}, 86{sub Rb}, 170{sub Tm}; Contribution a l'etude de la desintegration beta et a l'etude de la structure nucleaire a l'aide d'experiences sur certaines cascades beta-gamma: 198{sub Au}, 86{sub Rb}, 170{sub Tm}

Energy Technology Data Exchange (ETDEWEB)

Lachkar, J [Commissariat a l' Energie Atomique, Bruyeres-le-Chatel (France). Centre d' Etudes; Paris-11 Univ., fabulte des Sciences 91 - Orsay (France)

1969-07-01

{beta}{gamma} directional angular correlations and shapes of inner beta spectra leading to the first excited level of the final nucleus enable one to determine the nuclear matrix elements typical of the {beta} transition. In the three observed first forbidden cases: {sup 170}Tm, {sup 86}Rb, {sup 198}Au, these matrix elements do not confirm the independent shell model theory. Other hypotheses are then suggested and discussed. (author) [French] Les experiences de correlation angulaire {beta}{gamma} et l'etude du spectre {beta} conduisant au premier niveau excite du noyau final permettent de determiner les elements de matrices nucleaires caracteristiques de cette transition. Dans les trois cas etudies (transitions une fois interdites): {sup 170}Tm, {sup 86}Rb, {sup 198}Au, ces elements de matrices ne peuvent etre retrouves a l'aide du modele en couches et a particules independantes. D'autres hypotheses sont alors emises et discutees. (auteur)

Automatic classification of gammas-gamma coincidence matrices; Clasificacion automatizada de matrices de coincidencias Gamma-Gamma

Energy Technology Data Exchange (ETDEWEB)

Los Arcos Merino, J M; Gonzalez, J A

1978-07-01

The information obtained during a coincidence experiment, recorded on magnetic tape by a MULTI-8 minicomputer, is transferred to a new tape in 36 bit words, using the program LEC0M8. The classification in two dimensional matrix form is carried out off-line, on a magnetic disk file, by the program CLAFI. On finishing classification one obtains a copy of the coincidence matrix on the second magnetic tape. Both programs are written to be processed in that order with the UNIVAC 1106 computer of J.E.N. (Author) 4 refs.

Minicomputer system for radiochemical analysis by coincidence spectrometry

International Nuclear Information System (INIS)

Brauer, F.P.; Fager, J.E.

1979-01-01

Minicomputer-based coincidence analysis methods have been developed for use in performing radiochemical analysis by high-resolution x- and gamma-ray coincidence spectrometry. This paper describes the data-acquisition and analysis methods develolped for qualitative and quantitative analyses of coincidence spectrometric data. Data-acquisition capabilities include both direct multiparameter pulse-height analysis and buffered list-mode acquisition

Beta measurement evaluation and upgrade

International Nuclear Information System (INIS)

Swinth, K.L.; Rathbun, L.A.; Roberson, P.L.; Endres, G.W.R.

1986-01-01

This program focuses on the resolution of problems associated with the field measurement of the beta dose component at Department of Energy (DOE) facilities. The change in DOE programs, including increased efforts in improved waste management and decontamination and decommissioning (D and D) of facilities, coupled with beta measurement problems identified at Three Mile Island has increased the need to improve beta measurements. In FY 1982, work was initiated to provide a continuing effort to identify problems associated with beta dose assessment at DOE facilities. The problems identified resulted in the development of this program. The investigation includes (1) an assessment of measurement systems now in use, (2) development of improved calibration systems and procedures, (3) application of innovative beta dosimetry concepts, (4) investigation of new instruments or concepts for monitoring and spectroscopy, and (5) development of recommendations to assure an adequate beta measurement program within DOE facilities

Calculation of reasonable exemption levels for surface contamination by measuring overall gamma ray

International Nuclear Information System (INIS)

Ogino, Haruyuki; Hattori, Takatoshi

2008-01-01

The present regulation on surface contamination [Bq/cm 2 ] is determined from a simple radiological model for the most hazardous radionuclides (Pu-239 for alpha emitters and Sr-90 for beta emitters) and its extremely conservative model is applied for all other alpha and beta emitters. In this study, reasonable exemption levels for surface contamination are calculated for each radionuclide by adopting an original radiological dose evaluation method for surface contamination that can be applied in radiation safety, transport safety and waste safety. Furthermore, a new concept of judging the exemption by estimating the overall contamination [Bq] on the objects from the measurement of gamma ray has been designed and a reasonable value was derived. We conclude that the overall exemption levels obtained by gamma ray measurement can be one order smaller than those obtained by the conventional method for some radionuclides, such as Mn-54, Co-60, Nb-94, Cs-134, Cs-137, Eu-152 and Eu-154. (author)

Absolute measurement of a standard thermal-neutron flux using gold-detector activation; Mesure absolue d'un flux etalon de neutrons thermiques par activation de detecteurs d'or

Energy Technology Data Exchange (ETDEWEB)

Paternot, Y [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

1967-02-15

The density of neutrons in a standard stacking is determined between the zero-energy and the cut-off energy of 1 mm thick cadmium unit using a gold detector. Its absolute activity is measured using a 4 {pi} {beta} counter calibrated for 4 {pi} {beta},{gamma} coincidence by counting strongly active sources. The correction factor F due to the disintegration process for the gold is determined experimentally. {phi}{sub 0} = N{sub 0} {sup E}Cd{sub V0} = 6495 {+-} 1.5 per cent n/cm{sup 2}/s. (author) [French] La densite de neutrons dans un empilement etalon est determinee entre l'energie zero et l'energie de coupure d'un boitier de cadmium de 1 mm d'epaisseur au moyen d'un detecteur d'or. Son activite absolue est mesuree a l'aide d'un compteur 4 {pi} {beta} etalonne en coincidence 4 {pi} {beta},{gamma} par comptage de sources fortement actives. Le facteur de correction F d au schema de desintegration de l'or est determine experimentalement. {phi}{sub 0} = N{sub 0} {sup E}Cd{sub V0} = 6495 {+-} 1.5 pour cent n/cm{sup 2}/s. (auteur)

$\\beta$3$p$-spectroscopy and proton-$\\gamma$ width determination in the decay of $^{31}$Ar

CERN Multimedia

We propose to perform a detailed study of the $\\beta$-decay of the dripline nucleus $^{31}$Ar. This will allow a detailed study of the $\\beta$-delayed 3$p$-decay as well as provide important information on the resonances of $^{30}$S and $^{29}$P, in particular the ratio between the $p$- and $\\gamma$- partial widths relevant for astrophysics.

GammaWorkshops Proceedings

International Nuclear Information System (INIS)

Ramebaeck, H.; Straelberg, E.; Klemola, S.; Nielsen, Sven P.; Palsson, S.E.

2012-01-01

Due to a sparse interaction during the last years between practioners in gamma ray spectrometry in the Nordic countries, a NKS activity was started in 2009. This GammaSem was focused on seminars relevant to gamma spectrometry. A follow up seminar was held in 2010. As an outcome of these activities it was suggested that the 2011 meeting should be focused on practical issues, e.g. different corrections needed in gamma spectrometric measurements. This three day's meeting, GammaWorkshops, was held in September at Risoe-DTU. Experts on different topics relevant for gamma spectrometric measurements were invited to the GammaWorkshops. The topics included efficiency transfer, true coincidence summing corrections, self-attenuation corrections, measurement of natural radionuclides (natural decay series), combined measurement uncertainty calculations, and detection limits. These topics covered both lectures and practical sessions. The practical sessions included demonstrations of tools for e.g. corrections and calculations of the above meantioned topics. (Author)

GammaWorkshops Proceedings

Energy Technology Data Exchange (ETDEWEB)

Ramebaeck, H. (ed.) (Swedish Defence Research Agency (Sweden)); Straalberg, E. (Institute for Energy Technology, Kjeller (Norway)); Klemola, S. (Radiation and Nuclear Safety Authority, STUK (Finland)); Nielsen, Sven P. (Technical Univ. of Denmark. Risoe National Lab. for Sustainable Energy, Roskilde (Denmark)); Palsson, S.E. (Icelandic Radiation Safety Authority (Iceland))

2012-01-15

Due to a sparse interaction during the last years between practioners in gamma ray spectrometry in the Nordic countries, a NKS activity was started in 2009. This GammaSem was focused on seminars relevant to gamma spectrometry. A follow up seminar was held in 2010. As an outcome of these activities it was suggested that the 2011 meeting should be focused on practical issues, e.g. different corrections needed in gamma spectrometric measurements. This three day's meeting, GammaWorkshops, was held in September at Risoe-DTU. Experts on different topics relevant for gamma spectrometric measurements were invited to the GammaWorkshops. The topics included efficiency transfer, true coincidence summing corrections, self-attenuation corrections, measurement of natural radionuclides (natural decay series), combined measurement uncertainty calculations, and detection limits. These topics covered both lectures and practical sessions. The practical sessions included demonstrations of tools for e.g. corrections and calculations of the above meantioned topics. (Author)

The Absolute Standardization Method of 18F by Using 4π(PC)-γ Coincidence Counting System

International Nuclear Information System (INIS)

Pujadi

2003-01-01

The absolute standardization of 18 F radionuclide had been carried out using 4π(PC)-γ coincidence counting. The radionuclide 18 F fluoro 2 deoxyglucose (FDG) was the quantity used at nuclear medicine in diagnosis of oncology. The radionuclide 18 F had been produced by 18 O(p,n) 18 F reaction in a cyclotron. Source preparation had been done by gravimetry method after source was dissolved in aquadest. The samples have been measured using 4π(PC)-γ coincidence counting on different three window gamma energy, the gamma windows were set on 511 keV peak, 1022 keV and above 511 keV region. The result of measurement on 1022 keV peak and above 511 keV region, are fairly good with discrepancy about 0.15%, but the linearity of gamma window above 511 keV is the best with R 2 = 0.8287. The measurement on 511 keV gamma window region gave the result with difference 2.28% compared with another two region. (author)

New information on the $\\beta$-decay of $^{11}$Li from Doppler broadened $\\gamma$-lines

CERN Document Server

Fynbo, H O U; Cederkäll, J; Courtin, S; Dessagne, P; Jonson, B; Le Scornet, G; Nilsson, T; Nyman, G H; Poirier, E; Riisager, K; Tengblad, O; Wilhelmsen, K

2004-01-01

The $\\gamma$-ray spectrum following $\\beta$-decay of $^{11}$Li has been remeasured at the ISOLDE facility at CERN. Two new transitions were observed through the use of large Ge-detectors. Most $\\gamma$-decays will follow P-delayed neutron emission. Information on the energy of the neutron is derived from analysis of the $\\gamma$-line-shape and used to construct a partial decay scheme for $^{11}$Li. Lifetime values for the 1$^{-}$ and 2$^{-}$ levels in $^{10}$Be are also derived. A new partial decay scheme is presented. (43 refs).

Gamma-ray spectroscopy of neutron-rich products of heavy-ion collisions

Energy Technology Data Exchange (ETDEWEB)

Carpenter, M.P.; Janssens, R.V.F.; Ahmad, I. [and others

1995-08-01

Thick-target {gamma}{gamma} coincidence techniques are being used to explore the spectroscopy of otherwise hard-to-reach neutron-rich products of deep-inelastic heavy ion reactions. Extensive {gamma}{gamma} coincidence measurements were performed at ATLAS using pulsed beams of {sup 80}Se, {sup 136}Xe, and {sup 238}U on lead-backed {sup 122,124}Sn targets with energies 10-15% above the Coulomb barrier. Gamma-ray coincidence intensities were used to map out yield distributions with A and Z for even-even product nuclei around the target and around the projectile. The main features of the yield patterns are understandable in terms of N/Z equilibration. We had the most success in studying the decays of yrast isomers. Thus far, more than thirty new {mu}s isomers in the Z = 50 region were found and characterized. Making isotopic assignments for previously unknown {gamma}-ray cascades proves to be one of the biggest problems. Our assignments were based (a) on rare overlaps with radioactivity data, (b) on the relative yields with different beams, and (c) on observed cross-coincidences between {gamma} rays from light and heavy reaction partners. However, the primary products of deep inelastic collisions often are sufficiently excited for subsequent neutron evaporation, so {gamma}{gamma} cross-coincidence results require careful interpretation.

The beta decay asymmetry parameter of 35Ar

International Nuclear Information System (INIS)

Garnett, J.D.

1987-11-01

The beta decay asymmetry parameter for 35 Ar = 35 Cl + e + + nu/sub e/ has been remeasured in order to resolve a long standing puzzle. Previous asymmetry measurements, when combined with the comparative half-life, yield a value for the vector coupling constant, G/sub v/, that is in serious disagreement with the accepted value. We produced polarized 35 Ar by a (p,n) reaction on 35 Cl using the polarized proton beam provided by Lawrence Berkeley Laboratory's 88-Inch Cyclotron. The polarization of the 35 Ar was determined by measuring the asymmetry of the positrons produced in 35 Ar decay to the first excited state in 35 Cl (branching ratio = 1.3%) in coincidence with a 1219.4 keV gamma ray. Our result, A 0 = 0.49 +- 0.10, combined with the comparative half-life yields a value for G/sub v/ in agreement with the accepted value

RBE [relative biological effectiveness] of tritium beta radiation to gamma radiation and x-rays analyzed by both molecular and genetic methods

International Nuclear Information System (INIS)

Lee, W.R.

1988-01-01

The relative biological effectiveness (RBE) of tritium beta radiation to 60 Co gamma radiation was determined using sex-linked recessive lethals (SLRL) induced in Drosophila melanogaster spermatozoa as the biological effect. The SLRL test, a measure of mutations induced in germ cells transmitted through successive generations, yields a linear dose-response curve in the range used in these experiments. From these ratios of the slopes of the 3 H beta and the 60 Co gamma radiation linear dose response curves, an RBE of 2.7 is observed. When sources of error are considered, this observation suggests that the tritium beta particle is 2.7 ± 0.3 times more effective per unit of energy absorbed in inducing gene mutations transmitted to successive generation than 60 Co gamma radiation. Ion tracks with a high density of ions (high LET) are more efficient than tracks with a low ion density (low LET) in inducing transmissible mutations, suggesting interaction among products of ionization. Molecular analysis of x-ray induced mutations shows that most mutations are deletions ranging from a few base pairs as determined from sequence data to multi locus deletions as determined from complementation tests and Southern blots. 14 refs., 1 fig

Perturbed beta-gamma systems and complex geometry

Energy Technology Data Exchange (ETDEWEB)

Zeitlin, Anton M. [Department of Mathematics, Yale University, 442 Dunham Lab, 10 Hillhouse Avenue, New Haven, CT 06511 (United States)], E-mail: anton.zeitlin@yale.edu

2008-05-11

We consider the equations, arising as the conformal invariance conditions of the perturbed curved beta-gamma system. These equations have the physical meaning of Einstein equations with a B-field and a dilaton on a Hermitian manifold, where the B-field 2-form is imaginary and proportional to the canonical form associated with Hermitian metric. We show that they decompose into linear and bilinear equations and lead to the vanishing of the first Chern class of the manifold where the system is defined. We discuss the relation of these equations to the generalized Maurer-Cartan structures related to BRST operator. Finally we describe the relations of the generalized Maurer-Cartan bilinear operation and the Courant/Dorfman brackets.

Miniature proportional counter for compression measurements of laser-fusion targets

International Nuclear Information System (INIS)

Lane, S.M.; Dellis, J.H.; Bennett, C.K.; Campbell, E.M.

1981-10-01

Direct drive laser fusion targets consisting of DT gas encapsulated in glass microshells produce 14.1 MeV neutrons that can interact with silicon-28 nuclei in the glass to produce a 2.2 minute aluminum-28 activity. From the number of 28 Al nuclei created and the neutron yield, the compressed glass areal density can be found. To determine the number of activated atoms created, we collect approximately one-half of the target debris on a thin metal foil which is transferred to our beta-gamma coincidence detector. This detector consists of a 25 cm x 25 cm NaI(Tl) crystal having a 5 cm x 15 cm well. We have recently built a miniature proportional counter that fits into this well and is used to detect beta particles. It is constructed of .025 cm thick copper and has nine separate chambers through which methane flows. The coincidence background is 0.14 cpm and the measured beta efficiency is 45%. We are now building a .0125 cm thick counter made of aluminum having a predicted efficiency of > 90%

Increased gamma band power during movement planning coincides with motor memory retrieval.

Science.gov (United States)

Thürer, Benjamin; Stockinger, Christian; Focke, Anne; Putze, Felix; Schultz, Tanja; Stein, Thorsten

2016-01-15

The retrieval of motor memory requires a previous memory encoding and subsequent consolidation of the specific motor memory. Previous work showed that motor memory seems to rely on different memory components (e.g., implicit, explicit). However, it is still unknown if explicit components contribute to the retrieval of motor memories formed by dynamic adaptation tasks and which neural correlates are linked to memory retrieval. We investigated the lower and higher gamma bands of subjects' electroencephalography during encoding and retrieval of a dynamic adaptation task. A total of 24 subjects were randomly assigned to a treatment and control group. Both groups adapted to a force field A on day 1 and were re-exposed to the same force field A on day 3 of the experiment. On day 2, treatment group learned an interfering force field B whereas control group had a day rest. Kinematic analyses showed that control group improved their initial motor performance from day 1 to day 3 but treatment group did not. This behavioral result coincided with an increased higher gamma band power in the electrodes over prefrontal areas on the initial trials of day 3 for control but not treatment group. Intriguingly, this effect vanished with the subsequent re-adaptation on day 3. We suggest that improved re-test performance in a dynamic motor adaptation task is contributed by explicit memory and that gamma bands in the electrodes over the prefrontal cortex are linked to these explicit components. Furthermore, we suggest that the contribution of explicit memory vanishes with the subsequent re-adaptation while task automaticity increases. Copyright © 2015 Elsevier Inc. All rights reserved.

Beta decays of 126Cd and 126In to levels in 126In and 126Sn

International Nuclear Information System (INIS)

Gartner, M.L.

1979-01-01

A study of the beta decays of 126 Cd and 126 In using the TRISTAN on-line isotope separator facility is reported. Gamma-ray singles measurements were made for both decays usng Ge(Li) and LEPS (low energy photon spectrometer) detectors. In addition, gamma--gamma coincidence measurements and gamma multiscale measurements were made for both decays using Ge(Li) detectors. The half-life for 126 Cd was determined to be 0.506 +- 0.015 sec., and the half-lives for the low- and high-spin 126 In isomers were determined to be 1.83 +- 0.11 sec. and 1.96 +- 0.10 sec., respectively. A total of 11 gamma rays were observed in the decay of 126 Cd, and all but one were placed in a level scheme for 126 In. A total of 48 gamma rays were observed in the decay of the low- and high-spin 126 In isomers and all were placed in a level scheme for 126 Sn. Spin and parity assignments were deduced, whenever possible, on the basis of logft values and gamma decay selection rules. The 126 In decay schemes (one has been proposed for each isomer) are compared with earlier decay studies and with results from 124 Sn(t,p) 126 Sn reaction experiments. The systematics associated with the level schemes are discussed and a comparison is made with the nuclear shell model. 49 references

Copper(II) 12-metallacrown-4 complexes of alpha-, beta- and gamma-aminohydroxamic acids: a comparative thermodynamic study in aqueous solution.

Science.gov (United States)

Tegoni, Matteo; Remelli, Maurizio; Bacco, Dimitri; Marchiò, Luciano; Dallavalle, Francesco

2008-05-28

A complete thermodynamic study of the protonation and Cu(II) complex formation equilibria of a series of alpha- and beta-aminohydroxamic acids in aqueous solution was performed. The thermodynamic parameters obtained for the protonation of glycine-, (S)-alpha-alanine-, (R,S)-valine-, (S)-leucine-, beta-alanine- and (R)-aspartic-beta-hydroxamic acids were compared with those previously reported for gamma-amino- and (S)-glutamic-gamma-hydroxamic acids. The enthalpy/entropy parameters calculated for the protonation microequilibria of these three types of ligands are in very good agreement with the literature values for simple amines and hydroxamic acids. The pentanuclear complexes [Cu5L4H(-4)]2+ contain the ligands acting as (NH2,N-)-(O,O-) bridging bis-chelating and correspond to 12-metallacrown-4 (12-MC-4) which are formed by self-assembly between pH 4 and 6 with alpha-aminohydroxamates (HL), while those with beta- and gamma-derivatives exist in a wider pH range (4-11). The stability order of these metallomacrocycles is beta- > alpha- > gamma-aminohydroxamates. The formation of 12-MC-4 with alpha-aminohydroxamates is entropy-driven, and that with beta-derivatives is enthalpy-driven, while with gamma-GABAhydroxamate both effects occur. These results are interpreted on the basis of specific enthalpies or entropy contributions related to chelate ring dimensions, charge neutralization and solvation-desolvation effects. The enthalpy/entropy parameters of 12-MC-4 with alpha-aminohydroxamic acids considered are also dependent on the optical purity of the ligands. Actually, that with (R,S)-valinehydroxamic acid presents an higher entropy and a lower enthalpy value than those of enantiopure ligands, although the corresponding stabilities are almost equivalent. Moreover, DFT calculations are in agreement with a more exothermic enthalpy found for metallacrowns with enantiomerically pure ligands.

Contribution to the study of the sintering mechanisms of uranium powders in the {alpha}, {beta}, and {gamma} phases; Contribution a l'etude des mecanismes de frittage de poudre d'uranium en phases {alpha}, {beta}, et {gamma}

Energy Technology Data Exchange (ETDEWEB)

Pinteau, B [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1964-06-01

This study of the sintering mechanisms of uranium powders prepared by calci-thermy has been effected using continuous dilatometric measurements of the shrinkage of samples previously compressed at room temperature in purified argon gas. The tests carried out in the {alpha}, {beta} and {gamma} phases have led to the observation that the first step of the sintering appears to be governed by a volume self-diffusion mechanism; the activation heat values found for the sintering mechanisms are close to those deduced during studies of volume self-diffusion using the direct radio-tracer method. Furthermore it has been possible to show that in the {gamma} domain a second sintering mechanism occurs involving much longer sintering times; the heats of activation are much lower and this appears to indicate that there occurs a mechanism involving pore elimination by grain boundary diffusion of the vacancies. Furthermore, the dilatometric tests have shown the simultaneous influence of two important parameters in this work: grain boundaries and the diffusion coefficients. In the second part of the report are given results concerning the examination of sintered samples by various methods with a view to elucidating their structure and some of their physical properties. In this way it has been possible, by carrying out metallographic examinations after etching by ionic bombardment, to determine the changes in the porosity of the three phases {alpha}, {beta} and {gamma}, as well as the structure and the nature of the inclusions in each sample. Density and porosity measurements have also been carried out. The variations in these two sets of results make it possible to confirm the preceding dilatometric end micro-graphic examinations. Finally a detailed dilatometric study of the samples sintered in the {gamma} phase has shown the effect of oxide layers, associated with the existence of porosity, on the amplitudes and temperatures of the allotropic transformations, these latter being

Standardization of Radionuclides in the Electrotechnical Laboratory, Tokyo; Etalonnage des radionuclides au Laboratoire d'electrotechniqu e de Tokyo; Standartizatsiya radioizotopov v ehlektrotekhnichesko j laboratorii v Tokio; Normalizacion de radionuclidos en el Laboratorio de Electrotecnica de Tokio

Energy Technology Data Exchange (ETDEWEB)

Naito, Masashi; Inouye, Yajiro; Yura, Osamu [Electrotechnical Laboratory, Tokyo (Japan)

1960-06-15

Since 1953, the Electrotechnical Laboratory has undertaken absolute measurements of the activities of some radionuclides by means of the 4 {pi}{beta}l counting method and the coincidence method. The details of the counting methods used in our laboratory will be described. 1. 4 {pi}{beta} Counting Method - a bell type of 4 {pi}{beta} gas proportional counting apparatus was designed, and its counting characteristics were investigated, especially the dependence upon the counting gases. In measuring the activity, about 50 mg of the sample was taken on a thin film and then dried in the silica gel desiccator. One drop of a wetting solution was added on the dried sample so as to reduce the self-absorption, and the sample was dried again. The thin film was prepared through the procedure that synthetic resin (Kanevinyl-Rl 108 in cyclohexanon) spread over the water surface was taken up on the metal ring and then covered with very thin gold by means of the vacuum evaporating method. Sr{sup 80}-Y{sup 90}, Co{sup 60} and Cs{sup 137} were measured by the above procedure. The accuracies of the measurements were of the order of {+-} 2%. 2. 2 {pi} {alpha} Counting Method - The samples, RaD + E + F, U{sup 238} and Po{sup 210} were measured by means of the same apparatus as in the 4 {pi}{beta} counting method. The accuracies of the measurements were {+-}2, {+-}1 and {+-} 1% respectively. 3. Coincidence Counting Method - In the coincidence method, both {beta}-{gamma} and {gamma}-{gamma} counting methods were employed. A scintillation counter [Nal (Tl), 1'' {Phi} X 1''] was used as {gamma}-ray detector, and a GM counter as {beta}-ray detector. Recently, in order to examine the inherent difference between the 4 {pi} {beta} counting and the coincidence counting methods, instead of the GM counter, we devised a special type of the 4 {pi} {beta} proportional counter, which can also be used as 4 {pi} {beta} proportional counting apparatus independently, apart from the coincidence circuits

FPDCYS and FPSPEC: computer programs for calculating fission-product beta and gamma multigroup spectra from ENDF/B-IV data

International Nuclear Information System (INIS)

Stamatelatos, M.G.; England, T.R.

1977-05-01

FPDCYS and FPSPEC are two FORTRAN computer programs used at the Los Alamos Scientific Laboratory (LASL), in conjunction with the CINDER-10 program, for calculating cumulative fission-product beta and/or gamma multigroup spectra in arbitrary energy structures, and for arbitrary neutron irradiation periods and cooling times. FPDCYS processes ENDF/B-IV fission-product decay energy data to generate multigroup beta and gamma spectra from individual ENDF/B-IV fission-product nuclides. FPSPEC further uses these spectra and the corresponding nuclide activities calculated by the CINDER-10 code to produce cumulative beta and gamma spectra in the same energy grids in which FPDCYS generates individual isotope decay spectra. The code system consisting of CINDER-10, FPDCYS, and FPSPEC has been used for comparisons with experimental spectra and continues to be used at LASL for generating spectra in special user-oriented group structures. 3 figures

Soudan 2 muons in coincidence with BATSE bursts

International Nuclear Information System (INIS)

DeMuth, D.M.; Marshak, M.L.; Wagner, G.L.

1994-01-01

We explore the possibilities of statistically significant temporal and spatial coincidences between underground muons at Soudan 2 and Gamma Ray Bursts at the GRO-BATSE detector. Our search uses data from the April 91 to March 92 BATSE burst catalog to seek correlations within a 100 second window of coincidence. Sixteen of 180 BATSE triggers have temporally and spatially coincident muons in the Soudan 2 detector. We estimate the chance probability of each coincidence assuming the null hypothesis on the basis of a study of the multiplicities of spatially coincident muons observed over a two day period centered on the time of burst

Gamma-ray multiplicity measurement of the spontaneous fission decay of 252Cf in a segmented HPGe/BGO detector array

Energy Technology Data Exchange (ETDEWEB)

Bleuel, D L; Bernstein, L A; Burke, J T; Gibelin, J; Heffner, M D; Mintz, J; Norman, E B; Phair, L; Scielzo, N D; Sheets, S A; Snyderman, N J; Stoyer, M A; Wiedeking, M

2008-04-23

Coincident {gamma} rays from a {sup 252}Cf source were measured using an array of six segmented high-purity germanium (HPGe) Clover detectors each enclosed by 16 bismuth-germanate (BGO) detectors. The detectors were arranged in a cubic pattern around a 1 {micro}Ci {sup 252}Cf source to cover a large solid angle for {gamma}-ray measurement with a reasonable reconstruction of the multiplicity. Neutron multiplicity was determined in certain cases by identifying the prompt {gamma} rays from individual fission fragment pairs. Multiplicity distributions from previous experiments and theoretical models were convolved with the response function of the array and compared to the present results. These results suggest a {gamma}-ray multiplicity spectrum broader than previous measurements and models, and provide no evidence of correlation with neutron multiplicity.

Simplified slow anti-coincidence circuit for Compton suppression systems

International Nuclear Information System (INIS)

Al-Azmi, Darwish

2008-01-01

Slow coincidence circuits for the anti-coincidence measurements have been considered for use in Compton suppression technique. The simplified version of the slow circuit has been found to be fast enough, satisfactory and allows an easy system setup, particularly with the advantage of the automatic threshold setting of the low-level discrimination. A well-type NaI detector as the main detector surrounded by plastic guard detector has been arranged to investigate the performance of the Compton suppression spectrometer using the simplified slow circuit. The system has been tested to observe the improvement in the energy spectra for medium to high-energy gamma-ray photons from terrestrial and environmental samples

Study on dose distribution of therapeutic proton beams with prompt gamma measurement

Energy Technology Data Exchange (ETDEWEB)

Kim, J. W. [National Cancer Center, Seoul (Korea, Republic of); Min, C. H.; Kim, C. H.; Kim, D. K.; Yoon, M. Y. [Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of)

2007-03-15

The proton beam has an advantage of the sharp dose falloff in dose distribution called Bragg peak while conventional radiation therapy modalities such as photons exhibit considerable amount of exit dose. To take advantage of this property it is important to know the exact location of the distal dose falloff. An error can cause overdose to the normal tissue or underdose to the tumor volume. The only way of finding out the dose distribution in-situ in particle therapy is to measure the gammas produced by nuclear reactions with tissue materials. Two kinds of gammas can be used: one is prompt gamma and the other is coincident gamma from the positron-emission isotopes. We chose to detect prompt gammas, and developed a prompt gamma scanning system (PGS). The proton beams of the proton therapy facility at National Cancer Center were used. The gamma distribution was compared to the dose distribution measured by an ionization chamber at three different energies of 100, 150, 200 MeV's. The two distributions were well correlated within 1-2 mm. The effect of high-energy neutron appeared as blurred distribution near the distal dose falloff at the energy of 200 MeV. We then tested the PGS shielding design by adding additional layer of paraffin plates outside of the PGS, and found that fast neutrons significantly affect the background level. But the location of the dose fall-off was nearly coincident. The analysis of gamma energy spectrum showed that cut-off energy in gamma counting can be adjusted to enhance the signal to noise ratio. Further the ATOM phantom, which has similar tissue structure to human, was used to investigate the gamma distribution for the case of inhomogeneous matter. The location of dose falloff region was found to be well defined as for water phantom. Next an actual therapy beam, which was produced by the double scattering method, was used, for which the dose falloff by the gamma distribution was completely wiped out by background neutrons. It is not

High-energy Neutrino Emission from Short Gamma-Ray Bursts: Prospects for Coincident Detection with Gravitational Waves

Energy Technology Data Exchange (ETDEWEB)

Kimura, Shigeo S.; Murase, Kohta; Mészáros, Peter [Department of Physics, Pennsylvania State University, University Park, PA 16802 (United States); Kiuchi, Kenta [Center for Gravitational Physics, Yukawa Institute for Theoretical Physics, Kyoto, Kyoto 606-8502 (Japan)

2017-10-10

We investigate current and future prospects for coincident detection of high-energy neutrinos and gravitational waves (GWs). Short gamma-ray bursts (SGRBs) are believed to originate from mergers of compact star binaries involving neutron stars. We estimate high-energy neutrino fluences from prompt emission, extended emission (EE), X-ray flares, and plateau emission, and we show that neutrino signals associated with the EE are the most promising. Assuming that the cosmic-ray loading factor is ∼10 and the Lorentz factor distribution is lognormal, we calculate the probability of neutrino detection from EE by current and future neutrino detectors, and we find that the quasi-simultaneous detection of high-energy neutrinos, gamma-rays, and GWs is possible with future instruments or even with current instruments for nearby SGRBs having EE. We also discuss stacking analyses that will also be useful with future experiments such as IceCube-Gen2.

Study of principle error sources in gamma spectrometry. Application to cross sections measurement

International Nuclear Information System (INIS)

Majah, M. Ibn.

1985-01-01

The principle error sources in gamma spectrometry have been studied in purpose to measure cross sections with great precision. Three error sources have been studied: dead time and pile up which depend on counting rate, and coincidence effect that depends on the disintegration scheme of the radionuclide in question. A constant frequency pulse generator has been used to correct the counting loss due to dead time and pile up in cases of long and short disintegration periods. The loss due to coincidence effect can reach 25% and over, depending on the disintegration scheme and on the distance source-detector. After establishing the correction formula and verifying its validity for four examples: iron 56, scandium 48, antimony 120 and gold 196 m, an application has been done by measuring cross sections of nuclear reactions that lead to long disintegration periods which need short distance source-detector counting and thus correcting the loss due to dead time effect, pile up and coincidence effect. 16 refs., 45 figs., 25 tabs. (author)

Precision measurement of sub-nanosecond lifetimes of excited nuclear states using fast-timing coincidences with LaBr3(Ce) detectors

International Nuclear Information System (INIS)

Regan, P.H.

2015-01-01

Precision measurements of electromagnetic (EM) transition rates enable tests of models of internal nuclear structure. Measurements of transition rates can be used to infer the spin and parity differences between the initial and final discrete nuclear excited states via which the EM transition takes place. This short conference paper reports on developments of detection systems for the identification of discrete energy gamma-ray decays using arrays of halide-scintillation detectors acting in coincidence mode, which can be used to determine electromagnetic transition rates between excited nuclear states in the sub-nanosecond temporal regime. Ongoing development of a new multi-detector LaBr 3 (Ce) array for studies of exotic nuclei produced at the upcoming Facility for Anti-Proton and Ion Research (FAIR) as part of the NUSTAR–DESPEC project are presented, together with initial results from pre-NUSTAR implementations of this array for nuclear structure studies of neutron-rich fission fragment radionuclides at ILL-Grenoble, France and RIBF at RIKEN, Japan. - Highlights: • This paper reports on new detection systems for identification of gamma decays. • It focusses on using arrays of halide-scintillation detectors in coincidence mode. • These can determine lifetimes of nuclear states at the sub-ns level. • Plans for new LaBr3(Ce) arrays for studies of exotic nuclei are presented.

Beta and gamma oscillatory activities associated with olfactory memory tasks: different rhythms for different functional networks?

Science.gov (United States)

Martin, Claire; Ravel, Nadine

2014-01-01

Olfactory processing in behaving animals, even at early stages, is inextricable from top down influences associated with odor perception. The anatomy of the olfactory network (olfactory bulb, piriform, and entorhinal cortices) and its unique direct access to the limbic system makes it particularly attractive to study how sensory processing could be modulated by learning and memory. Moreover, olfactory structures have been early reported to exhibit oscillatory population activities easy to capture through local field potential recordings. An attractive hypothesis is that neuronal oscillations would serve to "bind" distant structures to reach a unified and coherent perception. In relation to this hypothesis, we will assess the functional relevance of different types of oscillatory activity observed in the olfactory system of behaving animals. This review will focus primarily on two types of oscillatory activities: beta (15-40 Hz) and gamma (60-100 Hz). While gamma oscillations are dominant in the olfactory system in the absence of odorant, both beta and gamma rhythms have been reported to be modulated depending on the nature of the olfactory task. Studies from the authors of the present review and other groups brought evidence for a link between these oscillations and behavioral changes induced by olfactory learning. However, differences in studies led to divergent interpretations concerning the respective role of these oscillations in olfactory processing. Based on a critical reexamination of those data, we propose hypotheses on the functional involvement of beta and gamma oscillations for odor perception and memory.

Beta and gamma oscillatory activities associated with olfactory memory tasks: Different rhythms for different functional networks?

Directory of Open Access Journals (Sweden)

Claire eMartin

2014-06-01

Full Text Available Olfactory processing in behaving animals, even at early stages, is inextricable from top down influences associated with odor perception. The anatomy of the olfactory network (olfactory bulb, piriform and entorhinal cortices and its unique direct access to the limbic system makes it particularly attractive to study how sensory processing could be modulated by learning and memory. Moreover, olfactory structures have been early reported to exhibit oscillatory population activities easy to capture through local field potential recordings. An attractive hypothesis is that neuronal oscillations would serve to ‘bind’ distant structures to reach a unified and coherent perception. In relation to this hypothesis, we will assess the functional relevance of different types of oscillatory activity observed in the olfactory system of behaving animals. This review will focus primarily on two types of oscillatory activities: beta (15-40 Hz and gamma (60-100 Hz. While gamma oscillations are dominant in the olfactory system in the absence of odorant, both beta and gamma rhythms have been reported to be modulated depending on the nature of the olfactory task. Studies from the authors of the present review and other groups brought evidence for a link between these oscillations and behavioral changes induced by olfactory learning. However, differences in studies led to divergent interpretations concerning the respective role of these oscillations in olfactory processing. Based on a critical reexamination of those data, we propose hypotheses on the functional involvement of beta and gamma oscillations for odor perception and memory.

Measurement system study using beta radiation for determining different paper superficial density

International Nuclear Information System (INIS)

Vieira, Thais Molina; Madi Filho, Tufic

2000-01-01

Radioisotopes are used now in some areas of the industry. For quality control purposes, they are used in non-destructive analysis (NDA) which is applied to the materials examination verifying if they are adequate to the patterns demanded by technical rules or the market. Gamma, beta or neutron radiation sources may be used to do NDA, depending on material to be analyzed and the industrial process. In this work, the study of measurement system applied to quality control area was conceived and, in the evaluation of the material in test, a radioactive beta source was used. A system was designed and mounted, using a plastic scintillator detector developed in the laboratories of the Centro de Tecnologia das Radiacoes from IPEN-CNEN/SP. Two beta sources were used in the operational test: 90 Sr/ 90 Y and 204 Tl. Measures were obtained using several paper samples with different superficial density in g/m 2 . With the results, an equation correlating the relative activity with the superficial density in g/m 2 was established. (author)

Measurements of the propagation speed of 511 KeV {gamma}-rays in air and other material media

Energy Technology Data Exchange (ETDEWEB)

Cavalcante, Jose T.P.D.; Silva, Paulo R.J.; Saitovitch, Henrique [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil)]. E-mails: thadeu@cbpf.br; prjs@cbpf.br; henrique@cbpf.br

2007-07-01

The propagation speeds of the 511 KeV {gamma}-rays were measured in several material media, based in a fast-slow coincidence method. The time-resolution of the instrumental system used to perform the experiments allows to get reliable results in covered distances of {approx} 40 cm. (author)

PET with coincidence gamma cameras - clinical benefit from the radiooncologists' point of view

International Nuclear Information System (INIS)

Richter, E.; Feyerabend, T.; Stallmann, C.; Lauer, I.; Baehre, M.

2001-01-01

Positron emission tomography with FDG (FDG-PET) is a new technique, which displays the cellular metabolic activity. Since tumors exhibit an increased metabolic activity when compared to normal tissue, this imaging modality has a particularly high importance. FDG-PET is not only useful for localizing and staging of malignant tumors, but also to evaluate therapy response. In this context, PET is superior to morphologically orientated modalities, because therapeutically induced changes in glucose metabolism precede morphologic alterations. Numerous studies indicate, that PET will play an important role in radiooncology concerning therapy planning and monitoring the effects of therapy during and after treatment. Further clinical studies are necessary to evaluate the information provided by FDG-PET more precisely. Coincidence gamma cameras with adequate imaging characteristics will gain enhanced importance to meet these increasing demands. (orig.) [de

A triple-crystal phoswich detector with digital pulse shape discrimination for alpha/beta/gamma spectroscopy

International Nuclear Information System (INIS)

White, Travis L.; Miller, William H.

1999-01-01

Researchers at the University of Missouri - Columbia have developed a three-crystal phoswich detector coupled to a digital pulse shape discrimination system for use in alpha/beta/gamma spectroscopy. Phoswich detectors use a sandwich of scintillators viewed by a single photomultiplier tube to simultaneously detect multiple types of radiation. Separation of radiation types is based upon pulse shape difference among the phosphors, which has historically been performed with analog circuitry. The system uses a GaGe CompuScope 1012, 12 bit, 10 MHz computer-based oscilloscope that digitally captures the pulses from a phoswich detector and subsequently performs pulse shape discrimination with cross-correlation analysis. The detector, based partially on previous phoswich designs by Usuda et al., uses a 10 mg/cm 2 thick layer of ZnS(Ag) for alpha detection, followed by a 0.254 cm CaF 2 (Eu) crystal for beta detection, all backed by a 2.54 cm NaI(Tl) crystal for gamma detection. Individual energy spectra and count rate information for all three radiation types are displayed and updated periodically. The system shows excellent charged particle discrimination with an accuracy of greater than 99%. Future development will include a large area beta probe with gamma-ray discrimination, systems for low-energy photon detection (e.g. Bremsstrahlung or keV-range photon emissions), and other health physics instrumentation

Contribution to the study of {beta} disintegration and of nuclear structure using experiments on certain {beta}-{gamma} cascades: 198{sub Au}, 86{sub Rb}, 170{sub Tm}; Contribution a l'etude de la desintegration beta et a l'etude de la structure nucleaire a l'aide d'experiences sur certaines cascades beta-gamma: 198{sub Au}, 86{sub Rb}, 170{sub Tm}

Energy Technology Data Exchange (ETDEWEB)

Lachkar, J. [Commissariat a l' Energie Atomique, Bruyeres-le-Chatel (France). Centre d' Etudes; Paris-11 Univ., fabulte des Sciences 91 - Orsay (France)

1969-07-01

{beta}{gamma} directional angular correlations and shapes of inner beta spectra leading to the first excited level of the final nucleus enable one to determine the nuclear matrix elements typical of the {beta} transition. In the three observed first forbidden cases: {sup 170}Tm, {sup 86}Rb, {sup 198}Au, these matrix elements do not confirm the independent shell model theory. Other hypotheses are then suggested and discussed. (author) [French] Les experiences de correlation angulaire {beta}{gamma} et l'etude du spectre {beta} conduisant au premier niveau excite du noyau final permettent de determiner les elements de matrices nucleaires caracteristiques de cette transition. Dans les trois cas etudies (transitions une fois interdites): {sup 170}Tm, {sup 86}Rb, {sup 198}Au, ces elements de matrices ne peuvent etre retrouves a l'aide du modele en couches et a particules independantes. D'autres hypotheses sont alors emises et discutees. (auteur)

Fundamentals of gamma-ray measurements and radiometric analyses

International Nuclear Information System (INIS)

Hochel, R.C.

1990-01-01

There are four primary modes of radioactive decay. All can be measured using various types of detectors and are the basis of many analytical techniques and much of what we know about the nucleus and its structure. Alpha particle emission occurs mostly in heavy nuclei of atomic number, Z, greater than 82 like Po, Ra, Th, and U, etc. Beta particles are simply electrons. They are emitted from the nucleus with a distribution of energies ranging from 0--3 MeV. Gamma-rays are photons with energies ranging from a few keV to 10 MeV or more. They usually follow alpha or beta decay, and depending on their energy, can have considerable range in matter. Neutrons are emitted in fission processes and also from a few of the highly excited fission product nuclei. Fission neutrons typically have energies of 1--2 MeV. Like gamma-rays, they have long ranges. The energies involved in nuclear decay processes are much higher than anything encountered in, say, chemical reactions. They are at the very top of the electromagnetic spectrum -- about a million times more energetic than visible light. As a result, these particles always produce ionization, either directly or indirectly, as they pass through matter. It is this ionization which is the basis of all radiation detectors

Assessment of gamma, beta and alpha-particle-emitting nuclides in marine samples

International Nuclear Information System (INIS)

Holm, E.

1997-01-01

Depending on the physical properties of radionuclides different systems must be used for their measurement. Most convenient is if gamma spectrometry can be used by germanium, Silicon or Scintillation detectors (eg. NaI). If, however, the main emission consists of beta or alpha particles or low-energy photons as is the case for radionuclides decaying by electron capture, radiochemical separation and specific source preparations must be undertaken. In such cases also the radiochemical yield must be determined. The radiochemical part mainly follows the lines presented by prof. T. Jaakkola, Department of Radiochemistry, Helsinki, Finland, at a course in radioecology in Lurid, 1991. For very long-lived radionuclides other methods such as mass spectrometry are superior although often associated with sophisticated expensive instrumentation. (author)

Identification of shell-model states in $^{135}$Sb populated via $\\beta^{-}$ decay of $^{135}$Sn

CERN Document Server

Shergur, J; Brown, B A; Cederkäll, J; Dillmann, I; Fraile-Prieto, L M; Hoff, P; Joinet, A; Köster, U; Kratz, K L; Pfeiffer, B; Walters, W B; Wöhr, A

2005-01-01

The $\\beta$- decay of $^{135}$Sn was studied at CERN/ISOLDE using a resonance ionization laser ion source and mass separator to achieve elemental and mass selectivity, respectively. $\\gamma$-ray singles and $\\gamma\\gamma$ coincidence spectra were collected as a function of time with the laser on and with the laser off. These data were used to establish the positions of new levels in $^{135}$Sb, including new low-spin states at 440 and 798 keV, which are given tentative spin and parity assignments of 3/2$^{+}$ and 9/2$^{+}$, respectively. The observed levels of $^{135}$Sb are compared with shell-model calculations using different single-particle energies and different interactions.

TL glow curve analysis of UV, beta and gamma induced limestone collected from Amarnath holy cave

Directory of Open Access Journals (Sweden)

Vikas Dubey

2015-01-01

Full Text Available The paper reports themoluminescence glow curve analysis of UV (ultraviolet, β (beta and γ (gamma induced limestone collected from Amarnath holy cave. The collected natural sample was characterized by X-ray diffraction (XRD technique and crystallite size calculated by Scherer's formula. Surface morphology and particle size was calculated by transmission electron microscopy (TEM study. Effect of annealing temperature on collected lime stone examined by TL glow curve study. The limestone was irradiated by UV radiation (254 nm source and the TL glow curve recorded for different UV exposure time. For beta irradiation Sr90 source was used and is shows intense peak at 256 °C with a shoulder peak at higher temperature range. For gamma radiation Co60 source and TL glow curve recorded for different doses of gamma. The kinetic parameters calculation was performed for different glow curve by computerized glow curve deconvolution (CGCD technique. The chemical composition of natural limestone was analyzed by energy dispersive X-ray spectroscopy (EDXS.

Influence of heat treatment in {beta} and {gamma} phases on the microscopic structure of uranium; Influence des traitements thermiques en phases {beta} et {gamma} sur la structure micrographique de l'uranium

Energy Technology Data Exchange (ETDEWEB)

Robillard, A

1958-06-02

A new method of microscopic examination of uranium is described. Electrolytic polishing and etching are carried out in an acetic acid-chromic acid bath. Atmospheric or anodic oxidation of the polished surface produces films which follow exactly changes in the structure of the underlying metal. This method is very sensitive to small variations of orientation in polygonized crystals. Using this method of examination of uranium, it was found that annealing U in the {gamma} phase followed by a cooling at a rate dependent of the annealing temperature, causes the formation of substructures different from those due to the polygonization of {alpha}-U. The substructures are indicated by the concentration of impurities on the dislocations induced by the stresses accompanying the allotropic transformation {gamma} {yields} {beta}. Similar treatment of the U-1.4% Cr alloy in which the {beta} phase is stabilized at room temperature, confirms this explanation. In addition to the polygonization substructures, sharp discontinuities can be observed in the network of sub- boundaries as a fine white edging. The comparison of these with the structure revealed by thermal etching in vacuum suggest that there are traces of the grain boundaries of the {gamma} phase. The method of etching followed by oxidation shows a haloed phase identified as UH{sub 3}. The conditions of appearance and disappearance of this phase are studied. The sensitivity of this method of detecting the last traces of H in U is very high. The dependence of the hydrogen content on the tensile properties of uranium metal was also studied. (author) [French] Une methode nouvelle d'examen micrographique de l'uranium a ete mise au point. Le polissage electrolytique et le 'gravage' sont effectues dans un bain acide acetique-acide chromique. L'oxydation atmospherique ou anodique de la surface polie conduit a la formation de couches epitaxiques d'oxyde. Cette methode est particulierement sensible aux faibles variations d

Radiosensitivity of Prostate Cancer Cell Lines for Irradiation from Beta Particle-emitting Radionuclide ¹⁷⁷Lu Compared to Alpha Particles and Gamma Rays.

Science.gov (United States)

Elgqvist, Jörgen; Timmermand, Oskar Vilhelmsson; Larsson, Erik; Strand, Sven-Erik

2016-01-01

The purpose of the present study was to investigate the radiosensitivity of the prostate cancer cell lines LNCaP, DU145, and PC3 when irradiated with beta particles emitted from (177)Lu, and to compare the effect with irradiation using alpha particles or gamma rays. Cells were irradiated with beta particles emitted from (177)Lu, alpha particles from (241)Am, or gamma rays from (137)Cs. A non-specific polyclonal antibody was labeled with (177)Lu and used to irradiate cells in suspension with beta particles. A previously described in-house developed alpha-particle irradiator based on a (241)Am source was used to irradiate cells with alpha particles. External gamma-ray irradiation was achieved using a standard (137)Cs irradiator. Cells were irradiated to absorbed doses equal to 0, 0.5, 1, 2, 4, 6, 8, or 10 Gy. The absorbed doses were calculated as mean absorbed doses. For evaluation of cell survival, the tetrazolium-based WST-1 assay was used. After irradiation, WST-1 was added to the cell solutions, incubated, and then measured for level of absorbance at 450 nm, indicating the live and viable cells. LNCaP, DU145, and PC3 cell lines all had similar patterns of survival for the different radiation types. No significant difference in surviving fractions were observed between cells treated with beta-particle and gamma-ray irradiation, represented for example by the surviving fraction values (mean±SD) at 2, 6, and 10 Gy (SF2, SF6, and SF10) for DU145 after beta-particle irradiation: 0.700±0.090, 0.186±0.050 and 0.056±0.010, respectively. A strong radiosensitivity to alpha particles was observed, with SF2 values of 0.048±0.008, 0.018±0.006 and 0.015±0.005 for LNCaP, DU145, and PC3, respectively. The surviving fractions after irradiation using beta particles or gamma rays did not differ significantly at the absorbed dose levels and dose rates used. Irradiation using alpha particles led to a high level of cell killing. The results show that the beta-particle emitter

Study of {sup 193}Os beta{sup -} decay; Estudo do decaimento beta{sup -} do {sup 193}Os

Energy Technology Data Exchange (ETDEWEB)

Zahn, Guilherme Soares

2006-07-01

In this work, the excited levels of {sup 193}Ir populated by the beta{sup -} decay of {sup 193}Os (T{sub 1/2} {approx} 30h) were investigated. For that purpose, {approx} 5 mg samples of 99%-enriched {sup 192}Os were irradiated under a thermal neutron flux of {approx} 10{sup 12} s{sup -1} and then analysed both using single gamma spectroscopy and a 4-detector multi parametric acquisition facility, which provided data for both a gamma gamma coincidence analysis and a directional angular correlation gamma gamma ({theta} ) study. From these data, 28 transitions were added to this decay scheme, 11 of which were previously known from nuclear reactions and 17 observed for the first time. Eight excited levels were also added to the decay scheme, 3 of which were known from nuclear reaction studies - the remaining 5 are suggested for the first time. Moreover, it was possible to confirm suspicions found in reference that the levels at 848.93 keV and 849.093 keV are indeed the same; it was also possible to confirm the existence of an excited level at 806.9 keV, which had been inferred, but not experimentally confirmed in beta decay studies to date. The angular correlation analysis allowed for the definition of the spin of the excited level at 874 keV as 5/2{sup +;} moreover, the results showed a 79% probability that the spin of the 1078 keV level is 5/2/'-, and also restricted the spin possibilities for the new excited level at 960 keV to two values (1/2 or 3/2). It was also possible to measure the multipolarity mixing ratio ({delta}{sub Ln+1}/L{sub n}) for 43 transitions - 19 of them for the first time and most of the others with a better precision than previously known. Finally, an attempt was made to understand the low-lying levels structure for this nucleus using a theoretical model, which reproduced the ground state and the two lowest-lying excited levels in {sup 193}Ir. (author)

Primary radioactivity standardization and gamma intensities determination of {sup 124}Sb

Energy Technology Data Exchange (ETDEWEB)

Iwahara, A. [Laboratorio Nacional de Metrologia das Radiacoes Ionizantes (LNMRI)/Instituto de Radioprotecao e Dosimetria (IRD)/Comissao Nacional de Energia Nuclear - CNEN, Av. Salvador Allende, s/no, Recreio, CEP 22780-160, Rio de Janeiro (Brazil)], E-mail: iwahara@ird.gov.br; Delgado, J.U.; Poledna, R.; Silva, C.J. da; Almeida, M.C.M. de; Silva, R.L. da [Laboratorio Nacional de Metrologia das Radiacoes Ionizantes (LNMRI)/Instituto de Radioprotecao e Dosimetria (IRD)/Comissao Nacional de Energia Nuclear - CNEN, Av. Salvador Allende, s/no, Recreio, CEP 22780-160, Rio de Janeiro (Brazil)

2009-04-21

A solution containing {sup 124}Sb was primarily standardized by the 4{pi}{beta}-{gamma} coincidence and anticoincidence extrapolation methods in the frame of the EUROMET 907 international comparison organized by Laboratoire National Henri Bequerel (LNHB)/France, in 2007. The main purposes of this exercise are the improvement in the uncertainties on the gamma-ray emission intensities and they clarify the discrepancies verified among the intensity values for many weak gamma rays reported in the literature. In this work the results of the activity obtained were used to determine the absolute and relative gamma-ray intensities using a planar and coaxial HPGe detectors calibrated by {sup 152}Eu and {sup 116m}Ho multi-gamma standard sources covering the energy range from 20 to 1408 keV. Additionally the half-life of {sup 124}Sb was determined following the decay of a solution of {sup 124}Sb contained in a glass ampoule over a period of three half-lives using two 4{pi}{gamma} ionization chambers.

Comparison of gamma- and beta radiation stress responses on anti-oxidative defense system and DNA modifications in Lemna minor

Energy Technology Data Exchange (ETDEWEB)

Van Hoeck, Arne [SCK.CEN, Boeretang 200 2400 Mol (Belgium); University of Antwerp, Groenenborgerlaan 171, 2020 Antwerpen (Belgium); Horemans, Nele; Van Hees, May; Nauts, Robin; Vandenhove, Hildegarde [SCK.CEN, Boeretang 200 2400 Mol (Belgium); Knapen, Dries; Blust, Ronny [University of Antwerp, Groenenborgerlaan 171, 2020 Antwerpen (Belgium)

2014-07-01

frond have been implemented in a dosimetric model derived from ERICA tool. This enabled a reliable comparison of dose-dependent endpoints between gamma- and beta radiation. Dose rates varied from 15 and 1500 mGy/hr, and 19 from 19000 μGy/hr for gamma- and beta radiation respectively. The classic growth related endpoints, like biomass and frond area, were measured and compared with biochemical and molecular endpoints. Therefore, DNA modifications were analyzed to evaluate biological DNA damage and ROS accumulation in plants together with activities of anti-oxidative enzymes to evaluate oxidative stress response. A dose-response curve with 60 percent growth inhibition was determined for gamma radiation and morphological growth effects in root system were observed for beta radiation. Preliminary results showed similar responses in peroxidase activities between both radiation types. These results and ongoing investigations will help to unravel the differences and similarities in response mechanisms for various radiation types in plant systems. As multiple levels in biological organisation of the organism were considered, and also different dose rates taken into account, this approach allows a better understanding the toxic mode of action of radiation stress in higher plants. This research was supported by the European Commission Contract Fission-2010-3.5.1-269672 to Strategy for Allied Radioecology (www.star-radioecology.org) and a project of the Fund for Scientific Research (FWO-Vlaanderen, G.A040.11N) (authors)

Studies on the decay of 160Tb to levels in 160Dy by Ge (Li)-Ge(Li)-coincidence system

International Nuclear Information System (INIS)

Hassan, A.M.; Abou-Zeid, M.A.; Mekamer, M.

1981-01-01

This work concerned with the study of the energy levels and the properties of gamma-ray transitions in 160 Dy resulting from the B-decay of the parent radioactive isotope 160 Tb (72 d.). These studies have been done by means of, single and gamma-gamma coincidence measurements. Log(ft). Internal Conversion Coefficient (ICC) values and the branching ratios have been calculated. The construction and testes of the Ge(Li)-Ge(Li) gamma-gamma coincidence spectrometer are presented. In addition to the previously reported transitions in three new transitions of energies 203, 420 and 1048 keV have been observed for the first time. The energy level at 1288.60 keV is confirmed, due to the presence of the 246 keV and 1005 keV gamma-ray transitions in the singles and gamma-gamma coincidence spectra. Furthermore the B-intensity feeding this level was calculated for the first time to be 0.08%. The log(ft) values of the energy level at 1288.6 keV was calculated for the first time to be 10.79. The energy level diagram of 160 Dy as summerised in the present work consists of 12 excited states, the levels at 581(6 + ) and 1391 keV reported by some authors were not encluded, since no transitions populated or depopulated these levels could be observed

Search for new physics in a precise 20F beta spectrum shape measurement

Science.gov (United States)

George, Elizabeth; Voytas, Paul; Chuna, Thomas; Naviliat-Cuncic, Oscar; Gade, Alexandra; Hughes, Max; Huyan, Xueying; Liddick, Sean; Minamisono, Kei; Paulauskas, Stanley; Weisshaar, Dirk; Ban, Gilles; Flechard, Xavier; Lienard, Etienne

2015-10-01

We are carrying out a measurement of the shape of the energy spectrum of β particles from 20F decay. We aim to achieve a relative precision below 3%, representing an order of magnitude improvement compared to previous experiments. This level of precision will enable a test of the so-called strong form of the conserved vector current (CVC) hypothesis, and should also enable us to place competitive limits on the contributions of exotic tensor couplings in beta decay. In order to control systematic effects, we are using a technique that takes advantage of high energy radioactive beams at the NSCL to implant the decaying nuclei in a scintillation detector deep enough that the emitted beta particles cannot escape. The β-particle energy is measured with the implantation detector after switching off the beam implantation. Ancillary detectors are used to tag the 1.633-MeV γ-rays following the β decay for coincidence measurements in order to reduce backgrounds. We will give an overview and report on the status of the experiment.

Gamma sensitivity of the Eberline PCM-1

International Nuclear Information System (INIS)

Blanton, J.D.

1988-01-01

This paper reports that normally, alarm setpoints for the Eberline PCM-1 series personnel contamination monitors are calculated based upon efficiencies measured using 100-cm 2 or larger beta or mixed beta-gamma sources. This simulates the type of contamination most frequently encountered on personnel and clothing--low-level, distributed beta-gamma emitters. In most circumstances, the PCM-1's sensitivity to the other type of contamination encountered in nuclear plant work--hot particles--would be expected to be the same as, or better than, its sensitivity to distributed contamination. However, particles that are deposited on skin or clothing can be partially shielded from the view of the PCM-1's detectors. In these situations, the PCm-1's sensitivity to gamma radiation may be more relevant than its sensitivity to betas

Primary standardization of {sup 152}Eu by 4πβ(LS) - γ (NaI) coincidence counting and CIEMAT-NIST method

Energy Technology Data Exchange (ETDEWEB)

Ruzzarin, A., E-mail: aruzzarin@nuclear.ufrj.br [Coordenacao de Pos-Graduacao e Pesquisa de Engenharia (LIN/PEN/COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Lab. de Instrumentação Nuclear; Cruz, P.A.L. da; Ferreira Filho, A.L.; Iwahara, A. [Instituto de Radioproteção e Dosimetria (LNMRI/IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil). Lab. Nacional de Metrologia das Radiações Ionizantes

2017-07-01

The 4πβ-γ coincidence counting and CIEMAT/NIST liquid scintillation method were used in the standardization of a solution of {sup 152}Eu. In CIEMAT/NIST method, measurements were performed in a Liquid Scintillation Counter model Wallac 1414. In the 4πβ-γ coincidence counting, the solution was standardized using a coincidence method with 'beta-efficiency extrapolation'. A simple 4πβ-γ coincidence system was used, with acrylic scintillation cell coupled to two coincident photomultipliers at 180° each other and NaI(Tl) detector. The activity concentrations obtained were 156.934 ± 0.722 and 157.403 ± 0.113 kBq/g, respectively, for CIEMAT/NIST and 4πβ-γ coincidence counting measurement methods. (author)

The influence of interleukin-1beta on gamma-glutamyl transpeptidase activity in rat hippocampus

Czech Academy of Sciences Publication Activity Database

Kaiser, M.; Mareš, Vladislav; Šťastný, František; Bubeníková-Valešová, V.; Lisá, Věra; Suchomel, P.; Balcar, V. J.

2006-01-01

Roč. 55, č. 4 (2006), s. 461-465 ISSN 0862-8408 R&D Projects: GA MZd(CZ) NF7626 Institutional research plan: CEZ:AV0Z50110509 Keywords : interleukin-1beta * gamma- glutamyltranspeptidase * hippocampus Subject RIV: ED - Physiology Impact factor: 2.093, year: 2006

Developments for the 6He beta - nu angular correlation experiment

Science.gov (United States)

Zumwalt, David W.

This thesis describes developments toward the measurement of the angular correlation between the beta and the antineutrino in the beta decay of 6He. This decay is a pure Gamow-Teller decay which is described in the Standard Model as a purely axial vector weak interaction. The angular correlation is characterized by the parameter abetanu = -1/3 in the Standard Model. Any deviation from this value would be evidence for tensor components in the weak interaction and would constitute new physics. A new method will be used to measure the parameter a betanu from 6He decays, featuring a magneto-optical trap that will measure the beta particle in coincidence with the recoiling 6Li daughter ion. This neutral atom trapping scheme provides cold, tightly confined atoms which will reduce systematic uncertainties related to the initial position of the decay. By knowing the initial position of the decay and measuring the time of flight of the recoiling 6Li daughter ion in coincidence with the beta, the angular correlation between the beta and the antineutrino can be deduced. We aim to measure a betanu first to the level of 1%, and eventually to the 0.1% level, which would represent an order of magnitude improvement in precision over past experiments. Towards this goal, we have designed, built, and successfully tested a liquid lithium target to provide >2×10. {10} 6He atoms/sto a low-background environment, which is the most intense source of 6He presently available. This allowed for an additional measurement of the 6He half-life (806.89 +/- 0.11stat +0.23-0.19syst ms) to be made with unprecedented precision, resolving discrepancies in past measurements. We have also tested our trapping and detection apparatus and have begun to record preliminary coincidence events.

Differential effects of whole-body {gamma}-irradiation on antinociception induced by morphine and {beta}-endorphin administered intracerebroventricularly in the mouse

Energy Technology Data Exchange (ETDEWEB)

Kim, J.K. [Korea Atomic Energy Research Inst., Taejon (Korea, Republic of); Chung, K.M.; Park, T.W.

2000-05-01

Two separate lines of evidence suggested the present study. First, intracerebroventricularly (i.c.v.) administered morphine (a {mu}-opioid receptor agonist) and {beta}-endorphin (an {epsilon}-opioid receptor agonist) produce antinociception by activating different descending pain inhibitory systems. Second, {gamma}-irradiation attenuates the acute antinociceptive action of i.c.v. injected morphine, but not DPLPE (a {delta}-opioid receptor agonist), in mice. These findings prompted us to investigate the effect of {gamma}-irradiation on the antinociception produced by i.c.v. injected morphine and {beta}-endorphin in male ICR mice. In one group, mice were exposed to whole-body irradiation at a dose of 5 Gy from a {sup 60}Co {gamma}-source and the antinociceptive effects were tested 5, 30, 60,90 and 180 min after irradiation using the 1% acetic acid-induced writhing test (10 ml/kg). The antinociceptive effect was produced time-dependently and reached its maximum at 90 min after irradiation. Thus, time was fixed in the following studies. In another group, mice were irradiated with 5 Gy and tested 90 minutes later for antinociception produced by i.c.v. administration of morphine (50 and 100 ng/mouse) or {beta}-endorphin (31 ng/mouse). Irradiation significantly potentiated the antinociception produced by {beta}-endorphin. However, the antinociception produced by morphine was not affected by irradiation. These results demonstrate a differential sensitivity of {mu}- and {epsilon}-opioid receptors to {gamma}-irradiation, in addition, support the hypothesis that morphine and {beta}-endorphin administered supraspinally produce antinociception by different neuronal mechanisms. (author)

Analysis of femtosecond pump-probe photoelectron-photoion coincidence measurements applying Bayesian probability theory

Science.gov (United States)

Rumetshofer, M.; Heim, P.; Thaler, B.; Ernst, W. E.; Koch, M.; von der Linden, W.

2018-06-01

Ultrafast dynamical processes in photoexcited molecules can be observed with pump-probe measurements, in which information about the dynamics is obtained from the transient signal associated with the excited state. Background signals provoked by pump and/or probe pulses alone often obscure these excited-state signals. Simple subtraction of pump-only and/or probe-only measurements from the pump-probe measurement, as commonly applied, results in a degradation of the signal-to-noise ratio and, in the case of coincidence detection, the danger of overrated background subtraction. Coincidence measurements additionally suffer from false coincidences, requiring long data-acquisition times to keep erroneous signals at an acceptable level. Here we present a probabilistic approach based on Bayesian probability theory that overcomes these problems. For a pump-probe experiment with photoelectron-photoion coincidence detection, we reconstruct the interesting excited-state spectrum from pump-probe and pump-only measurements. This approach allows us to treat background and false coincidences consistently and on the same footing. We demonstrate that the Bayesian formalism has the following advantages over simple signal subtraction: (i) the signal-to-noise ratio is significantly increased, (ii) the pump-only contribution is not overestimated, (iii) false coincidences are excluded, (iv) prior knowledge, such as positivity, is consistently incorporated, (v) confidence intervals are provided for the reconstructed spectrum, and (vi) it is applicable to any experimental situation and noise statistics. Most importantly, by accounting for false coincidences, the Bayesian approach allows us to run experiments at higher ionization rates, resulting in a significant reduction of data acquisition times. The probabilistic approach is thoroughly scrutinized by challenging mock data. The application to pump-probe coincidence measurements on acetone molecules enables quantitative interpretations

Standardization of electron-capture and complex beta-gamma radionuclides by the efficiency extrapolation method

International Nuclear Information System (INIS)

Grigorescu, L.

1976-07-01

The efficiency extrapolation method was improved by establishing ''linearity conditions'' for the discrimination on the gamma channel of the coincidence equipment. These conditions were proved to eliminate the systematic error of the method. A control procedure for the fulfilment of linearity conditions and estimation of residual systematic error was given. For law-energy gamma transitions an ''equivalent scheme principle'' was established, which allow for a correct application of the method. Solutions of Cs-134, Co-57, Ba-133 and Zn-65 were standardized with an ''effective standard deviation'' of 0.3-0.7 per cent. For Zn-65 ''special linearity conditions'' were applied. (author)

Beta and gamma decay heat measurements between 0.1s--50,000s for neutron fission of 235U, 238U and 239Pu. Final report, June 1, 1992--December 31, 1996

International Nuclear Information System (INIS)

Schier, W.A.; Couchell, G.P.

1996-01-01

This is a final reporting on the composition of separate beta and gamma decay heat measurements following neutron fission of 235 U and 238 U and 239 Pu and on cumulative and independent yield measurements of fission products of 235 U and 238 U. What made these studies unique was the very short time of 0.1 s after fission that could be achieved by incorporating the helium jet and tape transport system as the technique for transporting fission fragments from the neutron environment of the fission chamber to the low-background environment of the counting area. This capability allowed for the first time decay heat measurements to extend nearly two decades lower on the logarithmic delay time scale, a region where no comprehensive aggregate decay heat measurements had extended to. This short delay time capability also allowed the measurement of individual fission products with half lives as short as 0.2s. The purpose of such studies was to provide tests both at the aggregate level and at the individual nuclide level of the nation's evaluated nuclear data file associated with fission, ENDF/B-VI. The results of these tests are in general quite encouraging indicating this data base generally predicts correctly the aggregate beta and aggregate gamma decay heat as a function of delay time for 235 U, 238 U and 239 Pu. Agreement with the measured individual nuclide cumulative and independent yields for fission products of 235 U and 238 U was also quite good although the present measurements suggest needed improvements in several individual cases

Measurements of ambient radioxenon levels using the automated radioxenon sampler/analyzer (ARSA)

International Nuclear Information System (INIS)

McIntyre, J.I.; Abel, K.H.; Bowyer, T.W.; Hayes, J.C.; Heimbigner, T.R.; Panisko, M.E.; Reeder, P.L.; Thompson, R.C.

2001-01-01

The Pacific Northwest National Laboratory has developed an Automated Radioxenon Sampler/Analyzer (ARSA) in support of the Comprehensive Nuclear-Test-Ban-Treaty (CTBT) to measure four radioxenon isotopes: 131m Xe, 133m Xe, 133g Xe, and 135g Xe. This system uses a beta-gamma coincidence counting detector to produce two-dimensional plots of gamma-energy versus beta-energy. Betas and conversion electrons (CE) are detected in a cylindrical plastic scintillation cell and gamma and X-rays are detected in a surrounding NaI(Tl) scintillation detector. The ARSA has been field tested at several locations to measure the radioxenon concentrations. Most recently it has been deployed at the Institut fuer Atmosphaerische Radioaktivitaet in Freiburg, Germany. During the first 4 months of 2000 the measured 133 Xe concentrations have varied between 0.0 ± 0.1 and 110 ± 10 mBq/m 3 air. The longer lived 131m Xe (T 1/2 = 11.9 d) and short lived 135 Xe (T 1/2 = 9.1 h) have also been detected in small quantities, while 133m Xe concentrations have been consistent with zero. Minimum detectable concentration (MDC) calculations for 133g Xe fell well below the 1 mBq per standard-cubic-meter of air requirement adopted by the CTBT Preparatory Commission. A description of the radioxenon detector, the concentration and MDC calculations and preliminary results of the field test in Germany are presented. (author)

Angular dependence of Ll, L $\\alpha$ , L $\\beta$ and L $\\gamma$ X-ray differential and fluorescence cross-sections for Er, Ta, W, Au, Hg and Tl

CERN Document Server

Demir, L; Kurucu, Y; Karabulut, A; Sahin, Y; 10.1016/S0969-806X(02)00501-7

2003-01-01

Ll, L alpha , L beta and L gamma X-ray differential cross-sections, fluorescence cross-sections and L/sub i/-subshell ( sigma /sub L1/, sigma /sub L2/, and sigma /sub L3/) fluorescence cross-sections were measured for Er, Ta, W, Au, Hg, and Tl at an excitation energy of 59.6 keV using a Si(Li) detector. The differential cross-sections for these elements have been measured at different angles varying from 54 degrees to 153 degrees at intervals of 9 degrees . The Ll and L alpha groups in the L X-ray lines are found to be spatially anisotropic, while those in the L beta and L gamma peaks are isotropic. Experimental and theoretical values of L X-ray fluorescence cross- sections and L/sub i/-subshell X-ray fluorescence cross-sections were compared. (20 refs).

On the accuracy of gamma spectrometric isotope ratio measurements of uranium

Energy Technology Data Exchange (ETDEWEB)

Ramebäck, H., E-mail: henrik.ramebeck@foi.se [Swedish Defence Research Agency, FOI, CBRN Defence and Security, SE-901 82 Umeå (Sweden); Chalmers University of Technology, Department of Chemistry and Chemical Engineering, SE-412 96 Göteborg (Sweden); Lagerkvist, P.; Holmgren, S.; Jonsson, S.; Sandström, B.; Tovedal, A. [Swedish Defence Research Agency, FOI, CBRN Defence and Security, SE-901 82 Umeå (Sweden); Vesterlund, A. [Swedish Defence Research Agency, FOI, CBRN Defence and Security, SE-901 82 Umeå (Sweden); Chalmers University of Technology, Department of Chemistry and Chemical Engineering, SE-412 96 Göteborg (Sweden); Vidmar, T. [SCK-CEN, Belgian Nuclear Research Centre, Boeretang 200, 2400 Mol (Belgium); Kastlander, J. [Swedish Defence Research Agency, FOI, Defence and Security, Systems and Technology, SE-164 90 Stockholm (Sweden)

2016-04-11

The isotopic composition of uranium was measured using high resolution gamma spectrometry. Two acid solutions and two samples in the form of UO{sub 2} pellets were measured. The measurements were done in close geometries, i.e. directly on the endcap of the high purity germanium detector (HPGe). Applying no corrections for count losses due to true coincidence summing (TCS) resulted in up to about 40% deviation in the abundance of {sup 235}U from the results obtained with mass spectrometry. However, after correction for TCS, excellent agreement was achieved between the results obtained using two different measurement methods, or a certified value. Moreover, after corrections, the fitted relative response curves correlated excellently with simulated responses, for the different geometries, of the HPGe detector.

Measurement of the 2{nu}{beta}{beta} decay of {sup 100}Mo to the excited 0{sub 1}{sup +} state in the NEMO3 experiment

Energy Technology Data Exchange (ETDEWEB)

Vala, L

2003-09-01

The NEMO3 detector was designed for the study of double beta decay and in particular to search for the neutrinoless double beta decay process (0{nu}{beta}{beta}). The intended sensitivity in terms of a half-life limit for the 0{nu}{beta}{beta} decay is of the order of 10{sup 25} y which corresponds to an effective neutrino mass m{sub {nu}} on the level of (0.3 - 0.1) eV. The 0{nu}{beta}{beta} process is today the most promising test of the Majorana nature of the neutrino. The detector was constructed in the Modane Underground Laboratory (LSM) in France by an international collaboration including France, Russia, the Czech Republic, the USA, the UK, Finland, and Japan. The experiment has been taking data since May 2002. The quantity of {sup 100}Mo in the detector (7 kg) allows an efficient measurement of the two-neutrino double beta decay (2{nu}{beta}{beta}) of {sup 100}Mo to the excited 0{sub 1}{sup +} state (eeN{gamma} channel). Monte-Carlo simulations of the effect and of all the relative sources of background have been produced in order to define a set of appropriate selection criteria. Both Monte-Carlo simulations and special runs with sources of {sup 208}Tl and {sup 214}Bi showed that the only significant background in the eeN{gamma} channel comes from radon that penetrated inside the wire chamber of NEMO3. The experimental data acquired from May 2002 to May 2003 have been analysed in order to determine the signal from the 2{nu}{beta}{beta} decay of {sup 100}Mo to the excited 0{sub 1}{sup +} state and the corresponding background level. The physical result, which was obtained at the level of four standard deviations, is given in the form of an interval of half-life values at 95% confidence level: [5.84*10{sup 20}, 2.26*10{sup 21}] y for method A and [5.83*10{sup 20}, 1.71*10{sup 21}] y for method B. (author)

Gamma ampersand beta-gamma storm water monitor operability

International Nuclear Information System (INIS)

Tshiskiku, E.M.

1993-01-01

High Level Waste (HLW) facilities have nine storm water monitors that monitor storm water run off from different process areas for Cesium 137, a Gamma emitter. F - Area has three monitors: 907-2F, 907-3F and 907-4F while H - Area has six monitors: 907-2H, 907-3H, 907-4H, 907-5H, 907-6H and 907-7H (See attachments number-sign 1, number-sign 2 and number-sign 3 for location). In addition to monitoring for Cesium, 907-6H and 907-7H monitor for Strontium-90, a Beta emitter. Each monitor is associated with one of the following diversion gate encasements 907-1H, 241-15H, 241-51H, 907-1F or 241-23F. Normal flow of storm water from these diversion gate encasements is to the Four Mile Creek. When a storm water monitor detects radioactivity at a level exceeding the Four Mile Creek discharge limit, the monitor causes repositioning of the associated diversion gate to discharge to the H - Area retention basin 281-8H or the F - Area retention basin 281-8F. In response to recent OSR interpretation of storm water monitor calibration requirements, this report is provided to document operability and accuracy of radiation detection

ORNL shielded facilities capable of remote handling of highly radioactive beta--gamma emitting materials

International Nuclear Information System (INIS)

Whitson, W.R.

1977-09-01

A survey of ORNL facilities having adequate shielding and containment for the remote handling of experimental quantities of highly radioactive beta-gamma emitting materials is summarized. Portions of the detailed descriptions of these facilities previously published in ORNL/TM-1268 are still valid and are repeated

Beta-delayed neutron decay of $^{33}$Na

CERN Document Server

Radivojevic, Z; Caurier, E; Cederkäll, J; Courtin, S; Dessagne, P; Jokinen, A; Knipper, A; Le Scornet, G; Lyapin, V G; Miehé, C; Nowacki, F; Nummela, S; Oinonen, M; Poirier, E; Ramdhane, M; Trzaska, W H; Walter, G; Äystö, J

2002-01-01

Beta-delayed neutron decay of /sup 33/Na has been studied using the on-line mass separator ISOLDE. The delayed neutron spectra were measured by time-of-flight technique using fast scintillators. Two main neutron groups at 800(60) and 1020(80) keV were assigned to the /sup 33/Na decay, showing evidence for strong feeding of states at about 4 MeV in /sup 33/Mg. By simultaneous beta - gamma -n counting the delayed neutron emission probabilities P/sub 1n/ = 47(6)% and P /sub 2n/ = 13(3)% were determined. The half-life value for /sup 33 /Na, T/sub 1/2/ = 8.0(3) ms, was measured by three different techniques, one employing identifying gamma transitions and two employing beta and neutron counting. (21 refs).

Kinematic shifts of beta -delayed particles as a probe of beta - nu angular correlations

CERN Document Server

Clifford, E T H; Evans, H C; Fästermann, T; Hagberg, E; Hardy, J C; Jackson, K P; Koslowsky, V T; Schmeing, H; Schrewe, U J

1981-01-01

Beta-delayed particles undergo a kinematic shift in energy due to recoil motion of the daughter nucleus following beta decay. A careful measurement of this energy shift can be used to establish the ratio of vector to axial vector components in beta transitions. Alpha-beta coincidence data for the beta-delayed alpha decay of /sup 20/Na have been obtained. Component ratios for 6 transitions including the superallowed branch are found. Limits on charge dependent mixing with the analogue state are deduced for 5 states in /sup 20/Ne*. For the superallowed branch the axial vector component is found; the polar vector component is deduced and establishes a value for the vector weak coupling constant of G/sub V/=(1.355+or-0.036)*10/sup -49/ erg cm /sup 3/. (13 refs).

Decontamination Experiments on Intact Pig Skin Contaminated with Beta-Gamma- Emitting Nuclides

Energy Technology Data Exchange (ETDEWEB)

Edvardsson, K A; Hagsgaard, S [AB Atomenergi, Nykoeping (Sweden); Swensson, A [Dept. of Occupational Medicine, Karolinska Sjukhuset, Stockholm (Sweden)

1966-11-15

A number of decontamination experiments have been performed on intact pig skin. In most of the experiments NaI-131 in water solution has been utilized because this nuclide is widely used within the Studsvik research establishment, is easy to detect and relatively harmless, and is practical to use in these experiments. Among the {beta} {gamma}-nuclides studied 1-131 has furthermore proved to be the one most difficult to remove from the skin. The following conclusions and recommendations regarding the decontamination of skin are therefore valid primarily for iodine in the form of Nal, but are probably also applicable to many other {beta} {gamma}-nuclides. a) A prolonged interval between contamination and decontamination has a negative effect on the result of the decontamination. Therefore start decontamination as soon as possible after the contamination. b) Soap and water has proved to be the most suitable decontamination agent. A number of other agents have appeared to be harmful to the skin. Therefore, first of all use only soap and water in connection with gentle rubbing. c) No clear connection between the temperature of the water for washing and the result of the decontamination has been demonstrated. d) Skin not degreased before the contamination seems to be somewhat easier to decontaminate than degreased skin, particularly if the activity has been on the skin for a long time. Therefore do not remove the sebum of the skin when engaged on radioactive work involving contamination risks. e) Irrigation of the contaminated surface with a solution containing the corresponding inactive ions or ordinary water in large quantities may considerably decrease the skin contamination. f) In radioactive work of long duration involving high risks of contamination prophylactic measures in the form of a protective substance ('invisible glove'), type Kerodex, may make decontamination easier.

First Accurate Normalization of the $\\beta$-delayed $\\alpha$ Decay of $^{16}$N and Implications for the $^{12}$C$(\\alpha,\\gamma)^{16}$O Astrophysical Reaction Rate arXiv

CERN Document Server

Kirsebom, O.S.; Lica, R.; Munch, M.; Riisager, K.; Fynbo, H.O.U.; Borge, M.J.G.; Madurga, M.; Marroquin, I.; Andreyev, A.N.; Berry, T.A.; Christensen, E.R.; Fernández, P. Díaz; Doherty, D.T.; Van Duppen, P.; Fraile, L.M.; Gallardo, M.C.; Greenlees, P.T.; Harkness-Brennan, L.J.; Hubbard, N.; Huyse, M.; Jensen, J.H.; Johansson, H.; Jonson, B.; Judson, D.S.; Konki, J.; Lazarus, I.; Lund, M.V.; Marginean, N.; Marginean, R.; Perea, A.; Mihai, C.; Negret, A.; Page, R.D.; Pucknell, V.; Rahkila, P.; Sorlin, O.; Sotty, C.; Swartz, J.A.; Sørensen, H.B.; Törnqvist, H.; Vedia, V.; Warr, N.; De Witte, H.

The $^{12}$C$(\\alpha,\\gamma)^{16}$O reaction plays a central role in astrophysics, but its cross section at energies relevant for astrophysical applications is only poorly constrained by laboratory data. The reduced $\\alpha$ width, $\\gamma_{11}$, of the bound $1^-$ level in $^{16}$O is particularly important to determine the cross section. The magnitude of $\\gamma_{11}$ is determined via sub-Coulomb $\\alpha$-transfer reactions or the $\\beta$-delayed $\\alpha$ decay of $^{16}$N, but the latter approach is presently hampered by the lack of sufficiently precise data on the $\\beta$-decay branching ratios. Here we report improved branching ratios for the bound $1^-$ level and for $\\beta$-delayed $\\alpha$ emission. In the case of the $\\beta$-delayed $\\alpha$ branch, we find a $5\\sigma$ deviation from the literature value. With our new branching ratios, the constraints imposed on $\\gamma_{11}$ by the $\\beta\\alpha$-decay and $\\alpha$-transfer data are of similar precision and, for the first time, in good agreement. Th...

Meningioma growth and interferon beta-1b treated multiple sclerosis: coincidence or relationship?

International Nuclear Information System (INIS)

Drevelegas, A.; Xinou, E.; Karacostas, D.; Parissis, D.; Milonas, I.; Karkavelas, G.

2005-01-01

Although the coincidence of multiple sclerosis (MS) and central nervous system (CNS) tumors has been reported in over 30 cases in English literature, meningioma growth was associated with interferon-beta (INF-b) treated MS only in two of them. We report the case of a 19-year-old woman with clinically possible, laboratory supported MS, and a concomitant right intraventricular tumor with magnetic resonance imaging (MRI) characteristics consistent with meningioma (similar signal with grey matter on T1 and T2-weighted images and homogenous, intense enhancement). Two years after initiation of INF-b treatment, follow-up brain MRI revealed enlargement of the intraventricular mass and relative increase in the number of white matter lesions without significant clinical deterioration. She underwent almost total resection of the mass and histology confirmed the diagnosis of papillary meningioma. Based on the immunohistochemistry results, we speculate that INF-b resulted in meningioma growth by enhancing platelet derived growth factor (PDGF) receptors or/and down-regulating transforming growth factor receptors on the tumor itself. (orig.)

Meningioma growth and interferon beta-1b treated multiple sclerosis: coincidence or relationship?

Energy Technology Data Exchange (ETDEWEB)

Drevelegas, A.; Xinou, E. [AHEPA University Hospital, Aristotele University School of Medicine, Department of Radiology, Thessaloniki (Greece); Karacostas, D.; Parissis, D.; Milonas, I. [AHEPA University Hospital, Aristotele University School of Medicine, B' Department of Neurology, Thessaloniki (Greece); Karkavelas, G. [AHEPA University Hospital, Aristotele University School of Medicine, Laboratory of Pathology, Thessaloniki (Greece)

2005-07-01

Although the coincidence of multiple sclerosis (MS) and central nervous system (CNS) tumors has been reported in over 30 cases in English literature, meningioma growth was associated with interferon-beta (INF-b) treated MS only in two of them. We report the case of a 19-year-old woman with clinically possible, laboratory supported MS, and a concomitant right intraventricular tumor with magnetic resonance imaging (MRI) characteristics consistent with meningioma (similar signal with grey matter on T1 and T2-weighted images and homogenous, intense enhancement). Two years after initiation of INF-b treatment, follow-up brain MRI revealed enlargement of the intraventricular mass and relative increase in the number of white matter lesions without significant clinical deterioration. She underwent almost total resection of the mass and histology confirmed the diagnosis of papillary meningioma. Based on the immunohistochemistry results, we speculate that INF-b resulted in meningioma growth by enhancing platelet derived growth factor (PDGF) receptors or/and down-regulating transforming growth factor receptors on the tumor itself. (orig.)

Measurement of the beta-neutrino correlation in laser trapped ²¹Na

Energy Technology Data Exchange (ETDEWEB)

Scielzo, Nicholas David [Univ. of California, Berkeley, CA (United States)

2003-01-01

Trapped radioactive atoms are an appealing source for precise measurements of the beta-neutrino correlation coefficient, a, since the momentum of the neutrino can be inferred from the detection of the unperturbed low-energy recoil daughter nucleus. Sodium-21 is produced on-line at the 88'' cyclotron at Lawrence Berkeley National Laboratory, and 8e5 atoms have been maintained in a magneto-optical trap. A static electric field draws daughter Neon-21 ions to a microchannel plate detector and betas are detected in coincidence with a plastic scintillator beta detector. The Neon-21 time-of-flight distribution determines the beta neutrino correlation coefficient, a. The resulting charge-state distribution is compared to a simple model based on the sudden approximation which suggests a small but important contribution from nuclear recoil-induced ionization. A larger than expected fraction of the daughters are detected in positive charge-states, but no dependence on either the beta or recoil nucleus energy was observed. We find a = 0.5243 plus or minus 0.0092, which is in 3.6 sigma disagreement with the Standard Model prediction of a = 0.559 plus or minus 0.003. Aside from a deviation from the Standard Model, a possible explanation for the discrepancy is that the branching ratio to the first excited state is in error.

Low-level multicounter {beta}/{gamma} systems with external guards in surface and shallow underground laboratories

Energy Technology Data Exchange (ETDEWEB)

Theodorsson, P [Iceland Univ. (Iceland). Science Inst.

1997-03-01

When weak samples are measured it is important that they can be given ample counting time in order to obtain satisfactory accuracy and that the background count rate can be checked well. This calls for a high counting capacity, which multidetectors can bring us. I will discuss development possibilities of low-level {beta}/{gamma} multidetector systems with an external anticosmic shield that will in many cases be operated in underground laboratories. These simple and low-cost system can frequently help us in increasing the number of detectors. Three concepts are combined in these systems: (1) multidetectors, (2) an external anticosmic (or guard) detector arrangement and (3) overburden shielding. (orig.)

Influence of heat treatment in {beta} and {gamma} phases on the microscopic structure of uranium; Influence des traitements thermiques en phases {beta} et {gamma} sur la structure micrographique de l'uranium

Energy Technology Data Exchange (ETDEWEB)

Robillard, A

1958-06-02

A new method of microscopic examination of uranium is described. Electrolytic polishing and etching are carried out in an acetic acid-chromic acid bath. Atmospheric or anodic oxidation of the polished surface produces films which follow exactly changes in the structure of the underlying metal. This method is very sensitive to small variations of orientation in polygonized crystals. Using this method of examination of uranium, it was found that annealing U in the {gamma} phase followed by a cooling at a rate dependent of the annealing temperature, causes the formation of substructures different from those due to the polygonization of {alpha}-U. The substructures are indicated by the concentration of impurities on the dislocations induced by the stresses accompanying the allotropic transformation {gamma} {yields} {beta}. Similar treatment of the U-1.4% Cr alloy in which the {beta} phase is stabilized at room temperature, confirms this explanation. In addition to the polygonization substructures, sharp discontinuities can be observed in the network of sub- boundaries as a fine white edging. The comparison of these with the structure revealed by thermal etching in vacuum suggest that there are traces of the grain boundaries of the {gamma} phase. The method of etching followed by oxidation shows a haloed phase identified as UH{sub 3}. The conditions of appearance and disappearance of this phase are studied. The sensitivity of this method of detecting the last traces of H in U is very high. The dependence of the hydrogen content on the tensile properties of uranium metal was also studied. (author) [French] Une methode nouvelle d'examen micrographique de l'uranium a ete mise au point. Le polissage electrolytique et le 'gravage' sont effectues dans un bain acide acetique-acide chromique. L'oxydation atmospherique ou anodique de la surface polie conduit a la formation de couches epitaxiques d'oxyde. Cette methode est particulierement sensible

Design and test of 4πβ-γ coincidence measurement device based on DSP technology

International Nuclear Information System (INIS)

Zeng Herong; Feng Qijie; Leng Jun; Qian Dazhi; Bai Lixin; Zhang Yiyun

2012-01-01

The paper illustrates the hardware and software of the 4πβ-γ coincidence measurement device based on DSP technology in detail. In such device, the single-channel analyzer, gate generator, coincidence circuit and scalar in the traditional coincidence measurement device are replaced by the digital coincidence acquirer which is researched and manufactured by ourselves. Doing so, the measurement efficiency will be respectively improved, and the hardware cost will be lowered. The comparison experiment shows that the design of such device is a success. (authors)

On neutron activation analysis with γγ coincidence spectrometry

International Nuclear Information System (INIS)

Zeisler, Rolf; Danyal Turkoglu; Ibere Souza Ribeiro Junior; Shetty, M.G.

2017-01-01

A new γγ coincidence system has been set up at NIST. It is operated with a digital data finder supported by new software developed at NIST. The system is used to explore possible enhancements in instrumental neutron activation analysis (INAA) and study applicability to neutron capture prompt gamma activation analysis (PGAA). The performance of the system is tested with certified reference materials for efficiency calibration and quantitative performance. Comparisons of INAA results based on conventional gamma-ray spectrometry data with INAA results based on coincidence data obtained from the same samples show improvements in the counting uncertainties and demonstrates the quantitative accuracy of the new system. (author)

On the importance of low-energy beta-beams for supernova neutrino physics

International Nuclear Information System (INIS)

Jachowicz, N.; McLaughlin, G.C.

2005-01-01

Beta beams, which are neutrino beams produced by the beta decay of nuclei that have been accelerated to high gamma factor, were original proposed for high energy applications, such as the measurement of the third neutrino mixing angle θ 13 . Volpe suggested that a beta beam run at lower gamma factor, would be useful for neutrino measurements in the tens of MeV range. We suggest to exploit the flexibility these beta beam facilities offer, combined with the fact that beta-beam neutrino energies overlap with supernova-neutrino energies, to construct 'synthetic' spectra that approximate an incoming supernova-neutrino energy-distribution. Using these constructed spectra we are able to reproduce total and differential folded supernova-neutrino cross-sections very accurately. We illustrate this technique using Deuterium, 16 O, and 208 Pb. This technique provides an easy and straightforward way to apply the results of a beta-beam neutrino-nucleus measurement to the corresponding supernova-neutrino detector, virtually eliminating potential uncertainties due to nuclear-structure calculations. (author)

Stellar Sources of Gamma-ray Bursts

OpenAIRE

Luchkov, B. I.

2011-01-01

Correlation analysis of Swift gamma-ray burst coordinates and nearby star locations (catalog Gliese) reveals 4 coincidences with good angular accuracy. The random probability is 4\\times 10^{-5}, so evidencing that coincident stars are indeed gamma-ray burst sources. Some additional search of stellar gamma-ray bursts is discussed.

Measurement of K{sup {+-}}{yields}{pi}{sup {+-}}{gamma}{gamma} decays

Energy Technology Data Exchange (ETDEWEB)

Morales Morales, Cristina

2009-07-21

The goal of this thesis was an experimental test of an effective theory of strong interactions at low energy, called Chiral Perturbation Theory (ChPT). Weak decays of kaon mesons provide such a test. In particular, K{sup {+-}} {yields} {pi}{sup {+-}}{gamma}{gamma} decays are interesting because there is no tree-level O(p{sup 2}) contribution in ChPT, and the leading contributions start at O(p{sup 4}). At this order, these decays include one undetermined coupling constant, c. Both the branching ratio and the spectrum shape of K{sup {+-}} {yields} {pi}{sup {+-}}{gamma}{gamma} decays are sensitive to this parameter. O(p{sup 6}) contributions to K{sup {+-}} {yields} {pi}{sup {+-}}{gamma}{gamma} ChPT predict a 30-40% increase in the branching ratio. From the measurement of the branching ratio and spectrum shape of K{sup {+-}} {yields} {pi}{sup {+-}}{gamma}{gamma} decays, it is possible to determine a model dependent value of c and also to examine whether the O(p{sup 6}) corrections are necessary and enough to explain the rate. About 40% of the data collected in the year 2003 by the NA48/2 experiment have been analyzed and 908 K{sup {+-}} {yields} {pi}{sup {+-}}{gamma}{gamma} candidates with about 8% background contamination have been selected in the region with z=m{sup 2}{sub {gamma}}{sub {gamma}}/m{sub K}{sup 2}{>=}0.2. Using 5,750,121 selected K{sup {+-}} {yields} {pi}{sup {+-}}{pi}{sup 0} decays as normalization channel, a model independent differential branching ratio of K{sup {+-}} {yields} {pi}{sup {+-}}{gamma}{gamma} has been measured to be: BR(K{sup {+-}} {yields} {pi}{sup {+-}}{gamma}{gamma}, z{>=}0.2)=(1.018{+-}0.038{sub stat}{+-}0.039{sub syst}{+-}0.004{sub ext}).10{sup -6}. From the fit to the O(p{sup 6}) ChPT prediction of the measured branching ratio and the shape of the z-spectrum, a value of c=1.54{+-}0.15{sub stat}{+-}0.18{sub syst} has been extracted. Using the measured c value and the O(p{sup 6}) ChPT prediction, the branching ratio for z=m{sup 2}{sub

Performance of A Compact Multi-crystal High-purity Germanium Detector Array for Measuring Coincident Gamma-ray Emissions

Energy Technology Data Exchange (ETDEWEB)

Howard, Chris [Univ. of North Carolina, Chapel Hill, NC (United States); Triangle Univ. Nuclear Lab., Durham, NC (United States); Daigle, Stephen [Univ. of North Carolina, Chapel Hill, NC (United States); Triangle Univ. Nuclear Lab., Durham, NC (United States); Buckner, Matt [Univ. of North Carolina, Chapel Hill, NC (United States); Triangle Univ. Nuclear Lab., Durham, NC (United States); Erikson, Luke E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Runkle, Robert C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Stave, Sean C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Champagne, Art [Univ. of North Carolina, Chapel Hill, NC (United States); Triangle Univ. Nuclear Lab., Durham, NC (United States); Cooper, Andrew [Univ. of North Carolina, Chapel Hill, NC (United States); Triangle Univ. Nuclear Lab., Durham, NC (United States); Downen, Lori [Univ. of North Carolina, Chapel Hill, NC (United States); Triangle Univ. Nuclear Lab., Durham, NC (United States); Glasgow, Brian D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Kelly, Keegan [Univ. of North Carolina, Chapel Hill, NC (United States); Triangle Univ. Nuclear Lab., Durham, NC (United States); Sallaska, Anne [Univ. of North Carolina, Chapel Hill, NC (United States); Triangle Univ. Nuclear Lab., Durham, NC (United States)

2015-02-18

The Multi-sensor Airborne Radiation Survey (MARS) detector is a 14-crystal array of high-purity germanium (HPGe) detectors housed in a single cryostat. The array was used to measure the astrophysical S-factor for the ¹⁴N(p,γ)¹⁵O* reaction for several transition energies at an effective center of mass energy of 163 keV. Owing to the segmented nature of the MARS detector, the effect of gamma-ray summing was greatly reduced in comparison to past experiments which utilized large, single-crystal detectors. The new S-factor values agree within the uncertainties with the past measurements. Details of the analysis and detector performance will be presented.

Performance of a compact multi-crystal high-purity germanium detector array for measuring coincident gamma-ray emissions

Energy Technology Data Exchange (ETDEWEB)

Howard, Chris; Daigle, Stephen; Buckner, Matt [University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 (United States); Triangle Universities Nuclear Laboratory, Durham, NC 27708 (United States); Erikson, Luke E.; Runkle, Robert C. [Pacific Northwest National Laboratory, Richland, WA 99352 (United States); Stave, Sean C., E-mail: Sean.Stave@pnnl.gov [Pacific Northwest National Laboratory, Richland, WA 99352 (United States); Champagne, Arthur E.; Cooper, Andrew; Downen, Lori [University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 (United States); Triangle Universities Nuclear Laboratory, Durham, NC 27708 (United States); Glasgow, Brian D. [Pacific Northwest National Laboratory, Richland, WA 99352 (United States); Kelly, Keegan; Sallaska, Anne [University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 (United States); Triangle Universities Nuclear Laboratory, Durham, NC 27708 (United States)

2015-05-21

The Multi-sensor Airborne Radiation Survey (MARS) detector is a 14-crystal array of high-purity germanium (HPGe) detectors housed in a single cryostat. The array was used to measure the astrophysical S-factor for the {sup 14}N(p,γ){sup 15}O{sup ⁎} reaction for several transition energies at an effective center-of-mass energy of 163 keV. Owing to the granular nature of the MARS detector, the effect of gamma-ray summing was greatly reduced in comparison to past experiments which utilized large, single-crystal detectors. The new S-factor values agree within their uncertainties with the past measurements. Details of the analysis and detector performance are presented.

An electronic interface for acquisition of 12 delayed gamma-gammacoincidence spectra

International Nuclear Information System (INIS)

Domienikan, Claudio

2001-01-01

An electronic interface has been constructed to be used m conjunctionwith a Time differential Perturbed gamma-gamma Angular Correlation (TDPAC)spectrometer with four BaF 2 detectors. The routing interface is speciallydesigned to work with the Ortec model ADCAM 920-16 multichannel analyzer(MCA) having 16 multiplexed inputs, permitting the simultaneous acquisitionof 12 delayed gamma-gamma coincidence spectra. This innovation provides aconsiderable reduction in the experimental data acquisition time and as aconsequence permits an improvement in the precision of the final results ofthe hyperfine parameters deduced from the TDPAC measurements. The interfaceconsists of two distinct electronic circuits. A novel high performance analogdemultiplexer circuit is used to address the linear pulses from the time toamplitude converter (TAC) to the corresponding MCA inputs, according to thepair of detectors responsible for the given gamma-gamma coincidence.Validation of the gamma-gamma coincidence and control of the analogdemultiplexer are realized by a digital circuit, consisting basically ofmonostable multivibrators and decoders of High-Speed CMOS Logic (HCT). Theperformance of the routing interface was evaluated through several testmeasurements which included the time resolution and linearity of the system,the quadrupolar interaction in 181 Ta(Hf), 181 Ta(HfO 2 ), 111 Cd(Cd)and 111 Cd(Pd) samples, and the hyperfine magnetic field in 181 'Ta(Ni), 11 '1Cd(Ni) and 140 Ce(Gd) samples. The results of the hyperfineinteraction measurements are discussed and compared with previous results andserve to demonstrate the correct and efficient performance of the constructedinterface. (author)

A training and educational tool for neutron coincidence measurements

International Nuclear Information System (INIS)

Huszti, J.; Bagi, J.; Langner, D.

2009-01-01

Neutron coincidence counting techniques are widely used for nuclear safeguards inspection. They are based on the detection of time correlated neutrons created from spontaneous or induced fission of plutonium and some other actinides. IAEA inspectors are trained to know and to use this technique, but it is not easy to illustrate and explain the basics of the neutron coincidence counting. The traditional shift registers or multiplicity counters give only multiplicity distributions and the singles, doubles and triples count rates. Using the list mode method for the recording and evaluation of neutron coincidence data makes it easier to teach this technique. List mode acquisition is a relatively new way to collect data in neutron coincidence counting. It is based on the recording of the follow-up times of neutron pulses originating from a neutron detector into a file. The recorded pulse train can be evaluated with special software after the measurement. Hardware and software for list mode neutron coincidence acquisition have been developed in the Institute of Isotopes and is called a Pulse Train Reader. A system called Virtual Source for replaying pulse trains registered with the list mode device has also been developed. The list mode device and the pulse train 're-player' together build a good educational tool for teaching the basics of neutron coincidence counting. Some features of the follow-up time, multiplicity and Rossi-alpha distributions can be well demonstrated by replaying artificially generated or pre-recorded pulse trains. The choice of real sources is stored on DVD. There is no need to transport and maintain real sources for the training. Virtual sources also give the possibility of investigating rare sources that trainees would not have access to otherwise. (authors)

Nuclear level density and gamma strength function in 64Fe

Science.gov (United States)

Smith, M. K.; Spyrou, A.; Ahn, T.; Dombos, A. C.; Liddick, S. N.; Montes, F.; Naqvi, F.; Richman, D.; Schatz, H.; Brown, J.; Childers, K.; Crider, B. P.; Prokop, C. J.; Deleeuw, E.; Deyoung, P. A.; Langer, C.; Lewis, R.; Meisel, Z.; Pereira, J.; Quinn, S. J.; Schmidt, K.; Larsen, A. C.; Guttormsen, M.

2017-09-01

The Fe-Cd mass region exhibits enhanced collectivity and an unexpected increased in gamma-decay probability at low energies. These effects could be significant for r-process nucleosynthesis, where masses, beta-decay probabilities, and neutron capture cross sections are among the most important inputs. Neutron capture is notoriously difficult to measure; so the recent development of an indirect technique to constrain neutron-captures far from stability is especially valuable. This is the beta-Oslo method, which allows the extraction of the nuclear level density and gamma-ray strength function to compute neutron-capture cross sections. This work reports on 64Fe, populated via beta-decay of 64Mn at the National Superconducting Cyclotron Laboratory and measured with the 4pi Summing NaI (SuN) total gamma-ray spectrometer.

Nuclear structure of $^{229}$Th

CERN Document Server

Ruchowska, E; Zylicz, J; Mach, H; Kvasil, J; Algora, A; Amzal, N; Bäck, T; García-Borge, M J; Boutami, R; Butler, P A; Cederkäll, J; Cederwall, Bo; Fogelberg, B; Fraile-Prieto, L M; Fynbo, H O U; Hagebø, E; Hoff, P; Gausemel, H; Jungclaus, A; Kaczarowski, R; Kérek, A; Kurcewicz, W; Lagergren, K; Nacher, E; Rubio, B; Syntfeld, A; Tengblad, O; Wasilewski, A A

2006-01-01

Lifetimes of excited states in $^{229}$Th, populated in the $\\beta$-decay of $^{229}$Ac, have been measured using the advanced time-delayed $\\beta\\gamma\\gamma$(t)-method. Half-lives of 14 states have been determined including 11 of them for the first time. Twenty-seven new $\\gamma$-lines have been introduced into the $\\beta$-decay scheme of $^{229}$Ac based on results of $\\gamma\\gamma$-coincidence measurements. Reduced transition probabilities have been determined for more than 70 $\\gamma$-transitions in $^{229}$Th. Average ∣D$_{0}$∣ values of 0.029(1), 0.077(3) and 0.024(5) $e$ fm have been deduced for the lowest K$^{\\pi}$=1/2$^{\\pm}$ , 3/2$^{\\pm}$ and 5/2$^{\\pm}$ parity partner bands, respectively. Excited states in $^{229}$Th and experimental transition rates have been interpreted within the quasiparticle-plus-phonon model. The half-life of the 3.5 eV , 3/2$^{+}$ isomeric state is predicted to be about 10 h. Potential energy surfaces on the ($\\beta_{2}\\,,\\,\\beta_{3}$) plane for the lowest single quasi...

Liquid argon as active shielding and coolant for bare germanium detectors. A novel background suppression method for the GERDA 0{nu}{beta}{beta} experiment

Energy Technology Data Exchange (ETDEWEB)

Peiffer, J.P.

2007-07-25

Two of the most important open questions in particle physics are whether neutrinos are their own anti-particles (Majorana particles) as required by most extensions of the StandardModel and the absolute values of the neutrino masses. The neutrinoless double beta (0{nu}{beta}{beta}) decay, which can be investigated using {sup 76}Ge (a double beta isotope), is the most sensitive probe for these properties. There is a claim for an evidence for the 0{nu}{beta}{beta} decay in the Heidelberg-Moscow (HdM) {sup 76}Ge experiment by a part of the HdM collaboration. The new {sup 76}Ge experiment Gerda aims to check this claim within one year with 15 kg.y of statistics in Phase I at a background level of {<=}10{sup -2} events/(kg.keV.y) and to go to higher sensitivity with 100 kg.y of statistics in Phase II at a background level of {<=}10{sup -3} events/(kg.keV.y). In Gerda bare germanium semiconductor detectors (enriched in {sup 76}Ge) will be operated in liquid argon (LAr). LAr serves as cryogenic coolant and as high purity shielding against external background. To reach the background level for Phase II, new methods are required to suppress the cosmogenic background of the diodes. The background from cosmogenically produced {sup 60}Co is expected to be {proportional_to}2.5.10{sup -3} events/(kg.keV.y). LAr scintillates in UV ({lambda}=128 nm) and a novel concept is to use this scintillation light as anti-coincidence signal for background suppression. In this work the efficiency of such a LAr scintillation veto was investigated for the first time. In a setup with 19 kg active LAr mass a suppression of a factor 3 has been achieved for {sup 60}Co and a factor 17 for {sup 232}Th around Q{sub {beta}}{sub {beta}} = 2039 keV. This suppression will further increase for a one ton active volume (factor O(100) for {sup 232}Th and {sup 60}Co). LAr scintillation can also be used as a powerful tool for background diagnostics. For this purpose a new, very stable and robust wavelength

Cytokines interleukin-1beta and tumor necrosis factor-alpha regulate different transcriptional and alternative splicing networks in primary beta-cells

DEFF Research Database (Denmark)

Ortis, Fernanda; Naamane, Najib; Flamez, Daisy

2010-01-01

by the cytokines interleukin (IL)-1beta + interferon (IFN)-gamma and tumor necrosis factor (TNF)-alpha + IFN-gamma in primary rat beta-cells. RESEARCH DESIGN AND METHODS: Fluorescence-activated cell sorter-purified rat beta-cells were exposed to IL-1beta + IFN-gamma or TNF-alpha + IFN-gamma for 6 or 24 h......-cells, with temporal differences in the number of genes modulated by IL-1beta + IFNgamma or TNF-alpha + IFN-gamma. These cytokine combinations induced differential expression of inflammatory response genes, which is related to differential induction of IFN regulatory factor-7. Both treatments decreased the expression...... of genes involved in the maintenance of beta-cell phenotype and growth/regeneration. Cytokines induced hypoxia-inducible factor-alpha, which in this context has a proapoptotic role. Cytokines also modified the expression of >20 genes involved in RNA splicing, and exon array analysis showed cytokine...

System for ν-ν-coincidence spectra processing with data compression

International Nuclear Information System (INIS)

Byalko, A.A.; Volkov, N.G.; Tsupko-Sitnikov, V.M.; Churakov, A.K.

1982-01-01

Calculational algorithm and program for analyzing gamma-gamma coincidence spectra based on using the method of expansion in singular values for data compression (the SVD method) are described. Results of the testing of the program during the processing of coincidence spectrum for the low-energy region of transitions corresponding to decay 164 Lu → 164 Yb are given. The program is written in the FORTRAN language and is realized by the ES-1040 computer. The counting time constitutes about 20 min. It is concluded that the use of the SVD method permits to correct the data at the expense of distortion filtration caused with statistical deviations and random interferences, at that not distorting the initial data. The data compressed correspond more to theoretical suggestions of forms of semiconductor detector lines and two-dimensional line in the coincidence spectrum

Coincidence corrected efficiency calibration of Compton-suppressed HPGe detectors

Energy Technology Data Exchange (ETDEWEB)

Aucott, Timothy [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Brand, Alexander [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); DiPrete, David [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2015-04-20

The authors present a reliable method to calibrate the full-energy efficiency and the coincidence correction factors using a commonly-available mixed source gamma standard. This is accomplished by measuring the peak areas from both summing and non-summing decay schemes and simultaneously fitting both the full-energy efficiency, as well as the total efficiency, as functions of energy. By using known decay schemes, these functions can then be used to provide correction factors for other nuclides not included in the calibration standard.

Design and operation of a prototype incinerator for beta-gamma waste

International Nuclear Information System (INIS)

Farber, M.G.; Hootman, H.E.; Becker, G.W. Jr.; Makohon, P.A.

1981-01-01

A full-scale test incinerator has been built at the Savannah River Laboratory to provide a design basis for a radioactive facility that will burn low-level beta-gamma contaminated waste. The processing steps include waste feed loading, incineration, ash residue packaging, and off-gas cleanup. Both solid and liquid waste will be incinerated during the test program. The components of the solid waste are cellulose, latex, polyethylene, and PVC; the solvent is composed of n-paraffin and TBP. A research program will confirm the feasibility of the design and determine the operating parameters

'Dip-sticks' calibration handles self-attenuation and coincidence effects in large-volume gamma-ray spectrometry

CERN Document Server

Wolterbeek, H T

2000-01-01

Routine gamma-spectrometric analyses of samples with low-level activities (e.g. food, water, environmental and industrial samples) are often performed in large samples, placed close to the detector. In these geometries, detection sensitivity is improved but large errors are introduced due to self-attenuation and coincidence summing. Current approaches to these problems comprise computational methods and spiked standard materials. However, the first are often regarded as too complex for practical routine use, the latter never fully match real samples. In the present study, we introduce a dip-sticks calibration as a fast and easy practical solution to this quantification problem in a routine analytical setting. In the proposed set-up, calibrations are performed within the sample itself, thus making it a broadly accessible matching-reference approach, which is principally usable for all sample matrices.

Beta-decay and decay heat. Summary report of consultants' meeting

International Nuclear Information System (INIS)

Nicols, A.L.

2006-01-01

Experts on decay data and decay heat calculations participated in a Consultants' Meeting organized at IAEA Headquarters on 12-14 December 2005. Debate focused on the validation of decay heat calculations as a function of cooling time for fuel irradiated in power reactors through comparisons with experimental benchmark data. Both the current understanding and quantification of mean beta and gamma decay energies were reviewed with respect to measurements and the Gross Theory of Beta Decay. Particular emphasis was placed on the known development of total absorption gamma-ray spectroscopy (TAGS), and detailed discussions took place to formulate the measurement requirements for mean beta and gamma data of individual radionuclides. This meeting was organized in cooperation with the OECD/NEA Working Party for Evaluation and Cooperation (WPEC). Proposals and recommendations were made to resolve particular difficulties, and an initial list of fission products was produced for TAGS studies. The discussions, conclusions and recommendations of the meeting are briefly described in this report. (author)

A coincidence measurement of the D(gamma, pp pi(-)) cross section in the region of the Delta resonance

Science.gov (United States)

Quraan, Maher A.

Photonuclear reactions are excellent means for understanding final state interactions (FSI). The photon interacts only electromagnetically, allowing a clean separation of the strong interaction channels in the final state. The availability of high duty factor electron machines and large acceptance detectors in the past decade have allowed a further investigation of these effects covering wider regions of phase space. In this experiment, we have successfully measured the D(/gamma, pp/pi/sp-) reaction cross section at the Saskatchewan Accelerator Laboratory (SAL) utilizing the Saskatchewan- Alberta Large Acceptance Detector (SALAD). This is the first measurement of the /gamma D /to pp/pi/sp--cross section covering a wide range of phase space with an attempt to study the FSI's and the /Delta - N interaction that has successfully reproduced the normalizations. The cross section for this reaction is compared to the calculation of J. M. Laget. Laget's theory is quite successful in describing the shapes of the distributions. as well as the overall magnitude of the cross section. The different FSI's and the /Delta - N interaction have an overall effect of 10%-15% on the single differential cross section, with the calculation that includes /Delta - N interaction having the best normalization compared to the data.

The diagnosis of the gastric cancer using catheter-type semiconductor radiation detector. Comparison of diagnostic values of. beta. -emitting radionuclide label with. gamma. -emitting label

Energy Technology Data Exchange (ETDEWEB)

Sassa, R; Iwase, T [Asahi Life Foundation, Tokyo (Japan). Inst. for Adult Diseases; Sugita, T; Iio, M

1975-06-01

The diagnostic usefulness of /sup 32/P-phosphate for human gastric cancer, using a catheter-type semiconductor radiation detector (CASRAD) combined with gastrofiberscope technique, has already been reported by the authors. They have in addition used sup(99m)Tc-bleomycin, sup(99m)Tc-tetracycline in the diagnosis of experimental rabbit gastric cancer, too. In the present study, further refinement of the technique for the ..beta..-ray labeled substance (/sup 32/P-phosphate) for detection of the gastric cancer was compared with that of ..gamma..-ray labeled substance (sup(99m)Tc-tetracycline). A more correct diagnosis of the gastric cancer by in vivo measurement of beta activity could be obtained, when the collimater, made of stainless steel, was attached to the top of the detector. In this way contribution to the count from the adjacent tissues or organs could be eliminated. They were unable to produce an effective and useful collimater for ..gamma..-ray labeled substance which could to be used safely in vivo. Because of the unsatisfactory collimater, radioactivities of the adjacent organs caused on increase in the radioactivity of the background. Therefore inspite of the recent introduction of various sup(99m)Tc-tumor agents, these labels were not applicable to the CASRAD method. For such a small detector system, ..beta..-labels, represented by /sup 32/P-phosphate, was still prefererable to ..gamma..-labels.

Comparison of new and existing algorithms for the analysis of 2D radioxenon beta gamma spectra

International Nuclear Information System (INIS)

Deshmukh, Nikhil; Prinke, Amanda; Miller, Brian; McIntyre, Justin

2017-01-01

The aim of this paper is to compare radioxenon beta-gamma analysis algorithms using simulated spectra with experimentally measured background, where the ground truth of the signal is known. We believe that this is among the largest efforts to date in terms of the number of synthetic spectra generated and number of algorithms compared using identical spectra. We generate an estimate for the minimum detectable counts for each isotope using each algorithm. The paper also points out a conceptual model to put the various algorithms into a continuum. Our results show that existing algorithms can be improved and some newer algorithms can be better than the ones currently used. (author)

Chemical application of positron annihilation through triple coincidence measurement

International Nuclear Information System (INIS)

Yegnasubramanian, S.; Gangadharan, S.

1982-01-01

This report summarises the work on the application of triple coincidence measurement of annihilation radiation for providing chemical state information; the observations have been corroborated by angular correlation and Doppler broadening measurements and supplemented by the magnetic quenching in the angular correlation and peak-to-valley ratio in the Ge(Li) singles spectrum for the 511 keV line. (author)

Beta particle measurement fundamentals

International Nuclear Information System (INIS)

Alvarez, J.L.

1986-01-01

The necessary concepts for understanding beta particle behavior are stopping power, range, and scattering. Dose as a consequence of beta particle interaction with tissue can be derived and explained by these concepts. Any calculations of dose, however, assume or require detailed knowledge of the beta spectrum at the tissue depth of calculation. A rudimentary knowledge of the incident spectrum can be of use in estimating dose, interpretating dose measuring devices and designing protection. The stopping power and range based on the csda will give a conservative estimate in cases of protection design, as scattering will reduce the range. Estimates of dose may be low because scattering effects were neglected

Passive neutron coincidence counting with plastic scintillators for the characterization of radioactive waste drums

Energy Technology Data Exchange (ETDEWEB)

Deyglun, C.; Simony, B.; Perot, B.; Carasco, C. [CEA, DEN, Cadarache, Nuclear Measurement Laboratory, F-13108 Saint-Paul-lez-Durance (France); Saurel, N.; Colas, S. [CEA, DAM, Valduc, F-21120 Is-sur-Tille (France); Collot, J. [Laboratoire de Physique Subatomique et de Cosmologie, Universite Grenoble Alpes, CNRS/IN2P3, Grenoble (France)

2015-07-01

The quantification of radioactive material is essential in the fields of safeguards, criticality control of nuclear processes, dismantling of nuclear facilities and components, or radioactive waste characterization. The Nuclear Measurement Laboratory (LMN) of CEA is involved in the development of time-correlated neutron detection techniques using plastic scintillators. Usually, 3He proportional counters are used for passive neutron coincidence counting owing to their high thermal neutron capture efficiency and gamma insensitivity. However, the global {sup 3}He shortage in the past few years has made these detectors extremely expensive. In addition, contrary to {sup 3}He counters for which a few tens of microseconds are needed to thermalize fast neutrons, in view to maximize the {sup 3}He(n,p){sup 3}H capture cross section, plastic scintillators are based on elastic scattering and therefore the light signal is formed within a few nanoseconds, correlated pulses being detected within a few dozen- or hundred nanoseconds. This time span reflects fission particles time of flight, which allows reducing accordingly the duration of the coincidence gate and thus the rate of random coincidences, which may totally blind fission coincidences when using {sup 3}He counters in case of a high (α,n) reaction rate. However, plastic scintillators are very sensitive to gamma rays, requiring the use of a thick metallic shield to reduce the corresponding background. Cross talk between detectors is also a major issue, which consists on the detection of one particle by several detectors due to elastic or inelastic scattering, leading to true but undesired coincidences. Data analysis algorithms are tested to minimize cross-talk in simultaneously activated detectors. The distinction between useful fission coincidences and the correlated background due to cross-talk, (α,n) and induced (n,2n) or (n,n'γ) reactions, is achieved by measuring 3-fold coincidences. The performances of a

Atomic layer deposition α-Al2O3 diffusion barriers to eliminate the memory effect in beta-gamma radioxenon detectors

International Nuclear Information System (INIS)

Warburton, W.K.; Wolfgang Hennig; Bertrand, J.A.; George, S.M.; Steven Biegalski

2013-01-01

Well designed scintillator detectors, including such examples as ARSA, SAUNA, and XIA's 'PhosWatch', can readily achieve the state of the art radioxenon detection limits required for nuclear explosion monitoring. They are also reliable, robust detectors that do not require cryogenic cooling for operation. All three employ the principle of beta-gamma coincidence detection to reduce background counting rates, using a BC-404 plastic scintillator to detect the betas and a CsI or NaI scintillator to detect the gamma-rays. As a consequence of this commonality of design, all three also display a 'memory effect' arising from the diffusion of Xe into BC-404. Thus, when one sample is pumped out of the detector, a fraction remains behind, embedded in the BC-404, where it artificially raises the signal counting rate for the next sample. While this is not a fatal flaw in scintillator detectors, developing a method to eliminate the memory effect would significantly enhance their utility. This paper reports efforts to develop thin, amorphous Al 2 O 3 films, deposited by atomic layer deposition (ALD) to act as diffusion barriers on the BC-404 surfaces exposed to radioxenon. Using radon as a convenient substitute for Xe, film thicknesses between 2 and 10 nm were originally investigated and found to show a memory effect to varying degrees. A second set of 20 and 30 nm films was then produced, which appeared to completely eliminate the radon memory effect, but, when consequentially tested with radioxenon, were found to exhibit xenon memory effects that were approximately half of the effect found on uncoated BC-404. We draw two conclusions from this result. The first is that it will be necessary to develop an improved method for depositing thicker ALD Al 2 O 3 films at lower temperatures while still retaining high film quality. The second is that, since xenon is required to test for the xenon memory effect, we need a test method that does not require xenon radio-isotopes in order to

Arylation of beta, gamma-unsaturated lactones by a Heck-Matsuda reaction: an unexpected route to aryldiazene butenolides and pyridazinones

Energy Technology Data Exchange (ETDEWEB)

Taylor, Jason G.; Correia, Carlos Roque D., E-mail: roque@iqm.unicamp.b [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Inst. de Quimica

2010-07-01

The palladium catalysed coupling of aryldiazonium salts with {beta}-{gamma}-unsaturated lactones under basic conditions has been investigated. Both (3H)-furanone and {alpha}-angelicalactone were evaluated as substrates in the Heck Matsuda reaction but both failed to afford the desired arylated butenolides. Under basic conditions, {beta}-{gamma}-unsaturated lactones generate highly nucleophilic enolates that preferentially undergo azo coupling reactions with arenediazonium salts to afford aryldiazene butenolides. The electronic and steric effect of the substituents on the aryldiazonium salt in the azo coupling reaction is described. Aryldiazene-lactone derivatives were obtained in good yields from a highly facile and straightforward procedure. An aminoisomaleimide was formed from (3H)-furanone and cyclized to the corresponding pyridazinones in modest yield. (author)

Dynamic imaging with coincidence gamma camera

International Nuclear Information System (INIS)

Elhmassi, Ahmed

2008-01-01

In this paper we develop a technique to calculate dynamic parameters from data acquired using gamma-camera PET (gc PET). Our method is based on an algorithm development for dynamic SPECT, which processes all decency projection data simultaneously instead of reconstructing a series of static images individually. The algorithm was modified to account for the extra data that is obtained with gc PET (compared with SPEC). The method was tested using simulated projection data for both a SPECT and a gc PET geometry. These studies showed the ability of the code to reconstruct simulated data with a varying range of half-lives. The accuracy of the algorithm was measured in terms of the reconstructed half-life and initial activity for the simulated object. The reconstruction of gc PET data showed improvement in half-life and activity compared to SPECT data of 23% and 20%, respectively (at 50 iterations). The gc PET algorithm was also tested using data from an experimental phantom and finally, applied to a clinical dataset, where the algorithm was further modified to deal with the situation where the activity in certain pixels decreases and then increases during the acquisition. (author)

Pile-up correction for coincidence counting using a CAEN 1724 digitizer

Energy Technology Data Exchange (ETDEWEB)

Ribeiro Junior, Iberê S.; Zahn, Guilherme S.; Genezini, Frederico A., E-mail: gzahn@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2017-07-01

In conventional gamma-ray spectrometry, the probability of pile-up effects is considered to be proportional to the dead-time, and is usually neglected for low dead-times (below 4-5%). In gamma-gamma coincidence spectrometry, though, while the dead time takes into account only events that are actually digitized, the pile-up effects are proportional to the actual gamma-ray detection rate in each detector, not only to the ones that trigger the coincidence gate. Thus, the pile-up corrections may not be so easy to assess as in single spectrometry systems. In this work, a system composed of two HPGe detectors coupled to a CAEN v1724 digitizer is studied. A 3kBq {sup 60}Co source was analyzed, both alone and in the presence of other radioactive sources ({sup 137}Cs, {sup 133}Ba and {sup 152}Eu), and the resulting coincidence peak areas were compared to assess the effectiveness of two distinct corrections: a simple normalization by the live time of acquisition and the normalization by the count rate obtained using a pulse generator. The results obtained stress the need to use the pulse generator in this specific setup in order to get accurate results. (author)

Lifetime of the long-lived isomer of /sup 236/Np from. cap alpha. -,. beta. - and electron-capture decay measurements

Energy Technology Data Exchange (ETDEWEB)

Lindner, M.; Dupzyk, R.J.; Hoff, R.W.; Nagle, R.J. (California Univ., Livermore (USA). Lawrence Livermore National Lab.)

1981-01-01

The half-life of long-lived /sup 236/Np, due to ..cap alpha.., ..beta.. and electron-capture decay, was found to be 1.55 x 10/sup 5/ yr. Of all decays, 88% populate excited states in /sup 236/U and 12% populate levels in /sup 236/Pu. Lifetimes measured by growth of the ground states of /sup 236/U and /sup 236/Pu agree with values from corresponding ..gamma.. de-excitations in these daughter nuclei. Therefore, nearly all the electron-capture decays populate the 6/sup +/ level of the ground-state band in /sup 236/U. Similarly, essentially all the ..beta../sup -/ decay populates an analogous 6/sup +/ level in /sup 236/Pu, which de-excites through a previously unreported transition of 158.3 keV. If a very week ..gamma..-ray at 894 keV can be ascribed to a level in /sup 232/U populated by ..beta.. decay of /sup 232/Pa, its existence establishes a 0.2% ..cap alpha..-branching decay in /sup 236/Np.

A Gamma Scanner Using a Ge(Li) Semi-Conductor Detector, with the Possibility of Operation in the Anti-Coincidence Mode

Energy Technology Data Exchange (ETDEWEB)

Forsyth, R S; Blackadder, W H

1970-04-15

A fuel element transport flask has been modified as a facility for gamma scanning irradiated fuel elements up to a length of 75 cm. By means of a Ge(Li) semi-conductor detector, satisfactory activity profiles along the specimens have been obtained, permitting the location of individual fuel pellets. An annular plastic detector surrounding the Ge(Li) detector allows operation of the spectrometer in the anti-coincidence mode, and reduction of the Compton continuum by about 50% has been obtained.

A Gamma Scanner Using a Ge(Li) Semi-Conductor Detector, with the Possibility of Operation in the Anti-Coincidence Mode

International Nuclear Information System (INIS)

Forsyth, R.S.; Blackadder, W.H.

1970-04-01

A fuel element transport flask has been modified as a facility for gamma scanning irradiated fuel elements up to a length of 75 cm. By means of a Ge(Li) semi-conductor detector, satisfactory activity profiles along the specimens have been obtained, permitting the location of individual fuel pellets. An annular plastic detector surrounding the Ge(Li) detector allows operation of the spectrometer in the anti-coincidence mode, and reduction of the Compton continuum by about 50% has been obtained

Evaluation of transformation growth factor beta1, interleukin-10, and interferon-gamma in male symptomatic and asymptomatic dogs naturally infected by Leishmania (Leishmania) chagasi.

Science.gov (United States)

Corrêa, Ana Paula Ferreira Lopes; Dossi, Ana Cláudia Silva; de Oliveira Vasconcelos, Rosemeri; Munari, Danísio Prado; de Lima, Valéria Marçal Felix

2007-02-28

The aims of this study were to evaluate the immunomodulatory role of TGF-beta1, IL-10, and INF-gamma in spleen and liver extracts and supernatant cultures of white spleen cells from male symptomatic and asymptomatic dogs, naturally infected by Leishmania (Leishmania) chagasi. Thirty dogs from Araçatuba, São Paulo, Brazil, an endemic leishmaniosis area, were selected by positive ELISA serological reaction for Leishmania sp. and divided into two groups: asymptomatic (n=15) and symptomatic (n=15) consisting of animals with at least three characteristic signs (fever, dermatitis, lymphoadenopathy, onychogryphosis, weight loss, cachexia, locomotion problems, conjunctivitis, epistaxis, hepatosplenomegaly, edema, and apathy). After euthanasia, spleen and liver fragments were collected for ex vivo quantification of TGF-beta1, IL-10, and INF-gamma. Naturally active in vitro produced TGF-beta1 was also evaluated in spleen cell culture supernatant. Spleen and liver extract of asymptomatic dogs had higher mean TGF-beta1 levels than symptomatic dogs. High concentrations of IL-10 were found in spleen, and mainly in liver extract of both groups. Higher INF-gamma concentrations were found in spleen extracts of symptomatic dogs, and in liver extracts of asymptomatic dogs. Extract of this cytokine was lower in spleen extract. Although INF-gamma is being produced in canine infection, mean levels of TGF-beta1 and IL-10 from spleen and liver extracts were quantitatively much higher; suggesting that immune response in both asymptomatic and symptomatic dogs was predominantly type Th2.

Beta-glucan ameliorates gamma-rays induced oxidative injury in male Swiss albino rats

International Nuclear Information System (INIS)

Salama, S.F.

2011-01-01

1,3-beta-D-Glucan is a natural polysaccharide derived from the cell walls of bakers yeast Saccharomyces cerevsiae with immunoenhancing and potent antioxidant effects. This study investigated the pathways through which beta-glucan gavage treatment (50mg/kg) exerts its effect on radiation-induced oxidative damage in male rats. Beta-glucan was given orally to male rats; 3 hours post gamma-irradiation at dose 5Gy, for 10 and 20 days post-irradiation level were assayed, being remarkable indicators in cell oxidative stress. Results pointed out that irradiation at 5Gy significantly depressed all blood parameters, such as erythrocytes count (RBCs), hemoglobin content (Hb), hematocrit value (Hct), total leucocytes count and absolute lymphocytes and neutrophils counts, blood glutathione (GSH) level and conversely elevated level of serum ascorbyl radical (AsR), product of lipid peroxidation (MDA melanodialdehyde), triglycerides and cholesterol. Total leucocytes count and absolute lymphocytes and neutrophils counts, RBCs, Hb, Hct, blood GSH and serum MDA of irradiated animals receiving beta-glucan administration were exhibited significant differences compared to the irradiated group. Marrow count and the percentage of viability and spleenocytes viability were also significantly decreased. Beta-glucan treatment accelerates recovery of cell damage induced by ionizing irradiation through its potential immune-enhancing activity and free radical scavenging ability that is partially mediated through stimulation of immunohaematological system thus could play a role in regulating irradiation complications

A semiconductor beta ray spectrometer

International Nuclear Information System (INIS)

Bom, V.R.

1987-01-01

Measurement of energy spectra of beta particles emitted from nuclei in beta-decay processes provides information concerning the mass difference of these nuclei between initial and final state. Moreover, experimental beta spectra yield information on the feeding of the levels in the daughter nucleus. Such data are valuable in the construction and checking of the level schemes. This thesis describes the design, construction, testing and usage of a detector for the accurate measurement of the mentioned spectra. In ch. 2 the design and construction of the beta spectrometer, which uses a hyper-pure germanium crystal for energy determination, is described. A simple wire chamber is used to discriminate beta particles from gamma radiation. Disadvantages arise from the large amounts of scattered beta particles deforming the continua. A method is described to minimize the scattering. In ch. 3 some theoretical aspects of data analysis are described and the results of Monte-Carlo simulations of the summation of annihilation radiation are compared with experiments. Ch. 4 comprises the results of the measurements of the beta decay energies of 103-108 In. 87 refs.; 34 figs.; 7 tabs

Thermoluminescent characterization of thin films of aluminium oxide submitted to beta and gamma radiation; Caracterizacion termoluminiscente de peliculas delgadas de oxido de aluminio sometidas a radiacion beta y gamma

Energy Technology Data Exchange (ETDEWEB)

Villagran, E.; Escobar A, L.; Camps, E.; Gonzalez, P.R.; Martinez A, L. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

2002-07-01

By mean of the laser ablation technique, thin films of aluminium oxide have been deposited on kapton substrates. These films present thermoluminescent response (Tl) when they are exposed to beta and gamma radiation. The brilliance curves show two peaks between 112 C and 180 C. A dose-response relationship study was realized and the Tl kinetic parameters were determined using the computerized deconvolution of the brilliance curve (CGCD). The thin films of aluminium oxide have potential applications as ultra.thin radiation dosemeters. (Author)

Decay Spectroscopy for Nuclear Astrophysics: {beta}-delayed Proton Decay

Energy Technology Data Exchange (ETDEWEB)

Trache, L.; Simmons, E.; Spiridon, A.; McCleskey, M.; Roeder, B. T.; Tribble, R. E. [Texas A and M University, College Station, TX 77845 (United States); Saastamoinen, A.; Jokinen, A.; Aysto, J. [University of Jyvaskyla, Jyvaskyla (Finland); Davinson, T.; Woods, P. J. [University of Edinburgh, Edinburgh (United Kingdom); Pollacco, E.; Kebbiri, M. [CEA/IRFU Saclay (France); Pascovici, G. [IKP, Universitaet zu Koeln (Germany)

2011-11-30

Decay spectroscopy is one of the oldest indirect methods in nuclear astrophysics. We have developed at TAMU techniques to measure beta- and beta-delayed proton decay of sd-shell, proton-rich nuclei. The short-lived radioactive species are produced in-flight, separated, then slowed down (from about 40 MeV/u) and implanted in the middle of very thin Si detectors. These allowed us to measure protons with energies as low as 200 keV from nuclei with lifetimes of 100 ms or less. At the same time we measure gamma-rays up to 8 MeV with high resolution HPGe detectors. We have studied the decay of {sup 23}Al, {sup 27}P, {sup 31}Cl, all important for understanding explosive H-burning in novae. The technique has shown a remarkable selectivity to beta-delayed charged-particle emission and works even at radioactive beam rates of a few pps. The states populated are resonances for the radiative proton capture reactions {sup 22}Na(p,{gamma}){sup 23}Mg(crucial for the depletion of {sup 22}Na in novae), {sup 26m}Al(p,{gamma}){sup 27}Si and {sup 30}P(p,{gamma}){sup 31}S(bottleneck in novae and XRB burning), respectively. More recently we have radically improved the technique using a gas based detector we call AstroBox.

Study of Optically Stimulated Luminescence of LiF:Mg,Ti for beta and gamma dosimetry

International Nuclear Information System (INIS)

Matsushima, Luciana C.; Veneziani, Glauco R.; Campos, Letícia L.

2013-01-01

Modern advances in radiation medicine – radiodiagnosis, radiotherapy and interventional radiography – each present dosimetry challenges for the medical physicist that did not exist previously. In all of these areas a constant balance has to be made between the treatment necessary to destroy the tumor and the unnecessary exposure of healthy tissue. Innovative applications of OSL dosimetry are now appearing in each of these areas to help the medical physicist and oncologist design the most effective, and least deleterious, treatment for their patients. High sensitivity, precise delivery of light, fast readout times, simpler readers and easier automation are the main advantages of OSL in comparison with TLD. This work aimed to study the application of OSL technique using lithium fluoride dosimeters doped with magnesium and titanium (LiF:Mg,Ti) for application in beta and gamma dosimetry. -- Highlights: •Study of Optically Stimulated Luminescence of LiF:Mg,Ti and microLiF:Mg,Ti. •OSL response of TLD-100 dosimeters to beta and gamma radiation. •Analysis of repeatability and lowest levels of detection of detectors LiF:Mg,Ti

Beta, gamma contamination analysis of thermo luminescence dosimeter cassettes using Geiger Muller counting set up and gamma spectrometry techniques

International Nuclear Information System (INIS)

Prasad, S.K.; Sudheer, T.S.; Sahoo, L.; Vinayagam, Bhakti; Kamble, Mahesh; Khuspe, R.R.; Anilkumar, Rekha; Verma, K.K.

2009-01-01

Β-γ contamination cheek up of TLD cassettes were carried out and the isotopes found were 137 Cs, 106 Ru, 60 Co, 64 Cu, 144 Ce and 95 Nb with activity per square cm varying from 0.05-4.70 Bq/cm 2 with median value 1.3. The assessed dose in TLD was in the range of 2.10 mSv to 22.05 mSv for beta, 0.05 mSv to 5.25 mSv for gamma. The beta doses have median value of 6.19 mSv. This contamination may be due to active water contamination on TLD's of personnel working for irradiated fuel handling or work in fuel rod (under water) storage area. This gives a method to estimate skin exposure of personnel due to skin contamination during work. Chances of getting TLD's contaminated due to various reasons were studied. Contamination was found maximum inside the cassette box having area 16 cm 2 . In case of plastic pouch of TLD disc contamination was detected in three cases. Contamination level on TLD cassettes using GM counter was found in the range of 0.30-3.6 Bq/cm 2 for cassettes. By opening the window of the surveymeter contamination and field of these cassettes in closed condition were found to increase by 20% due to the measurement of beta dose. With the same condition contamination of TLD cassette in open condition was found five times more. This is due to the a-contamination which is five times more than a contamination, The most prominent isotope 137 Cs in common chemical forms are soluble in water and if inhaled or ingested are rapidly and completely absorbed in the lungs and across the gastrointestinal tract. Thus a skin contamination of most prominent isotope 137 Cs can lead to intake in addition to skin dose. Fading studies of contamination of TLD cassettes were carried out. It was found negligible after counting with GM counting set up after a period of 3 months. But one of the TLD cassettes was showing an 80% reduction of contamination after 3 months with GM counting set up, the contaminants being 141 Ce, 103 Ru and 95 Nb. The gamma peaks in the external exposure

Measurements of radionuclide activity by the (e-α, β, γ, Lx) coincidence method using electrons with energies of a few eV emitted from radionuclides

International Nuclear Information System (INIS)

Frolov, E.A.

1994-01-01

A study was made of the possibility of measuring radionuclide activities by the method of coincidence of electrons with energies of a few eV emitted from the valence shells of radioactive atoms with nuclear radiations. The low energy electrons were detected with a detector equipped with microchannel plates with trochoidal focusing of an original design. Photons were detected with NaI(TI) detectors. A 100 μm thick plastic scintillator was used to detect beta- and alpha-particles. The investigation shows that it is possible to use this method for accurate measurements of radionuclide activity. (orig.)

Measuring the radium quartet (228Ra, 226Ra, 224Ra, 223Ra) in seawater samples using gamma spectrometry

International Nuclear Information System (INIS)

Beek, P. van; Souhaut, M.; Reyss, J.-L.

2010-01-01

Radium isotopes are widely used in marine studies (eg. to trace water masses, to quantify mixing processes or to study submarine groundwater discharge). While 228 Ra and 226 Ra are usually measured using gamma spectrometry, short-lived Ra isotopes ( 224 Ra and 223 Ra) are usually measured using a Radium Delayed Coincidence Counter (RaDeCC). Here we show that the four radium isotopes can be analyzed using gamma spectrometry. We report 226 Ra, 228 Ra, 224 Ra, 223 Ra activities measured using low-background gamma spectrometry in standard samples, in water samples collected in the vicinity of our laboratory (La Palme and Vaccares lagoons, France) but also in seawater samples collected in the plume of the Amazon river, off French Guyana (AMANDES project). The 223 Ra and 224 Ra activities determined in these samples using gamma spectrometry were compared to the activities determined using RaDeCC. Activities determined using the two techniques are in good agreement. Uncertainties associated with the 224 Ra activities are similar for the two techniques. RaDeCC is more sensitive for the detection of low 223 Ra activities. Gamma spectrometry thus constitutes an alternate method for the determination of short-lived Ra isotopes.

Measurement of fission yields for 232-Th (n,f) at 14,7 MeV by direct gamma spectrometric method

International Nuclear Information System (INIS)

Chouak, K.; Berrada, M.; Embarech, K.

1994-01-01

Fission yields for the reaction 232-Th (n,f) were measured at 14,7 MeV using the activation technique with direct gamma spectrometric method. Neutrons were produced via the T(d,n) sup 4 He reaction. The neutron fluences were determined relative to the well-known sup 2 sup 7 Al(n,p) sup 2 sup 7 Mg or sup 2 sup 7 Al(n,alpha) sup 2 sup 4 Na cross section, according to the irradiation time. Yields of fission products were determined by measuring the induced gamma ray activities of the irradiated Th foils, using a calibrated Ge(Li) detector. All necessary corrections were taken into account: self absorption, coincidence losses and natural gamma rays. Fifty six cumulative yields were measured and only twenty one corresponding results were found in the literature (Crouch,1977). A satisfactory agreement is observed between our results and the published data with the exception of the masses:A=134 and A=140. 1 tab., 2 refs. (author)

Method and program for decay scheme reconstruction based on formal logical analysis of gamma-gamma coincidence matrix

International Nuclear Information System (INIS)

Adam, J.; Tsupko-Sitnikov, V.M.

1996-01-01

A new, rigorously substantiated approach to construction of decay schemes on the basis of γ-γ coincidence data is described. Complete decay modes (concrete cascades of transitions from excited to the ground-state of a nucleus excited in a decay or a reaction) and continuity regions in complete modes (regions of successive transitions) are isolated by logical operations with rows (columns) of a symmetrical coincidence matrix where rows (columns) correspond to energies of coinciding transitions and matrix elements are unities and zeros, depending on the presence or absence of the given coincidence. To reject false complete modes and continuity regions arising from incompleteness of the coincidence data and errors in them, energy selection is introduced for complete modes and continuity regions, which demands that total energy of their constituent transitions should be equal to total energy of some other complete modes and continuity regions and to the energies of singles. With the continuity regions found, it is possible to order transitions in the selected complete modes and to algorithmize matching of complete modes into a decay scheme. 10 refs., 3 figs

Partitioning diversity into independent alpha and beta components.

Science.gov (United States)

Jost, Lou

2007-10-01

Existing general definitions of beta diversity often produce a beta with a hidden dependence on alpha. Such a beta cannot be used to compare regions that differ in alpha diversity. To avoid misinterpretation, existing definitions of alpha and beta must be replaced by a definition that partitions diversity into independent alpha and beta components. Such a unique definition is derived here. When these new alpha and beta components are transformed into their numbers equivalents (effective numbers of elements), Whittaker's multiplicative law (alpha x beta = gamma) is necessarily true for all indices. The new beta gives the effective number of distinct communities. The most popular similarity and overlap measures of ecology (Jaccard, Sorensen, Horn, and Morisita-Horn indices) are monotonic transformations of the new beta diversity. Shannon measures follow deductively from this formalism and do not need to be borrowed from information theory; they are shown to be the only standard diversity measures which can be decomposed into meaningful independent alpha and beta components when community weights are unequal.

Quality assurance in field radiation measurements

International Nuclear Information System (INIS)

Howell, W.P.

1985-01-01

In most cases, an ion chamber radiation measuring instrument is calibrated in a uniform gamma radiation field. This results in a uniform ionization field throughout the ion chamber. Measurement conditions encountered in the field often produce non-uniform ionization fields within the ion chamber, making determination of true dose rates to personnel difficult and prone to error. Extensive studies performed at Hanford have provided appropriate correction factors for use with one type of ion chamber instrument, the CP. Suitable corrections are available for the following distinct measurement circumstances: (1) contact measurements on large beta and gamma sources, (2) contact measurements on small beta and gamma sources, (3) contact measurements on small-diameter cylinders, (4) measurements in small gamma beams, and (5) measurements at a distance from large beta sources. Recommendations are made for the implementation of these correction factors, in the interest of improved quality assurance in field radiation measurements. 12 references, 10 figures

International Standardization of Pure Beta Emitters

International Nuclear Information System (INIS)

Los Arcos, Jose Maria; Rodriguez, Leonor

2006-01-01

The paper describes the traditional methods of standardization of Pure Beta Emitters, their principal characteristics, advantage and drawbacks. It does comparisons between two metrological LSC methods: Triple to double coincidence ratio (TDCR) method and the CIEMAT/NIST method and presents the result obtained with several Key Comparisons serving as practical test of both methods. Both of them represent the siferrit of methods of standardization of pure (and mixed decay) radionuclides. ESIR WG of CCRI(II) is to implement a reference exchange system for the permanent equivalence of β, α and electron capture nuclides, similar to traditional SIR gamma. ESIR project is currently testing a new XAN scintillator and operational tests of the whole system at BIPM are expected by the end of 2006 (test restricted to ESIR NMI members)

Expression of human gamma-globin genes in human erythroleukemia (K562) cells.

Science.gov (United States)

Donovan-Peluso, M; Acuto, S; Swanson, M; Dobkin, C; Bank, A

1987-12-15

K562 cells express embryonic (epsilon) and fetal (gamma) globins and hemoglobins but not adult (beta) globin. To define the cis acting regulatory elements involved in the discrimination between gamma and beta genes, we have constructed chimeric genes composed of portions of gamma and beta and evaluated their expression in stable K562 transfectants. A gamma beta fusion gene containing gamma 5' sequences to the EcoRI site in exon 3 and beta sequences 3' is expressed at 10-40% that of the endogenous gamma level. In 50% of the lines, this fusion gene appropriately increases its expression in response to hemin, an inducer of endogenous globin gene expression in K562 cells. In contrast, a beta gamma fusion gene, containing beta sequences 5' to the EcoRI site in exon 3 and gamma sequences 3', is neither expressed nor correctly initiated. A beta gene containing gamma-intervening sequence (IVS) 2 accumulates an mRNA transcript when analyzed with a 3' beta probe. However, no correctly initiated beta mRNA is observed. A gamma gene with beta-IVS 2 is only inducible in one of six expressing clones. All the results are consistent with the presence of stage-specific trans acting factors in K562 cells that stimulate expression of gamma genes and suggest a significant role for gamma-IVS 2 in gamma gene expression.

Measurement of beta emitting radionuclides in dose calibrators routinely used in nuclear medicine departments

International Nuclear Information System (INIS)

Tastan, S.; Soylu, A.; Kucuk, O.; Ibis, E.

2004-01-01

Full text: Radionuclides for diagnostics purposes like Tc-99m, Tl-201, Ga-67 and In-111 are measured by using ionization type of dose calibrators. Therapeutic radionuclides, which emit both beta and gamma rays are detected by the same type of dose calibrators. Other therapeutic products like Y-90, P-32 and Sr-89 are pure beta emitters and they are gaining wider utility because various new therapy radiopharmaceuticals are being developed. The type of container material, like glass or plastic, may seriously affect radioactivity measurement due to attenuation, Since it is crucial to give the exact amount of radioactivity to the patient for therapy purposes, dedicated dose calibrators are specially manufactured for the measurement of these radionuclides. But these measuring systems are not widely available in nuclear medicine centers where therapy is applied to the patient. It is a known fact that dose calibrators routinely used in nuclear medicine departments can be calibrated for vials and syringes using standard sources of the same radioisotope. The method of calibration of Y-90 measurement for two ionization chamber dose calibrators available in the institute will be summarized in this presentation

Measurement of beta emitting radionuclides in dose calibrators routinely used in nuclear medicine departments

International Nuclear Information System (INIS)

Tastan, S.; Soylu, A.; Kucuk, O.; Ibis, E.

2004-01-01

Radionuclides for diagnostics purposes like Tc-99m, Tl-201, Ga-67 and In-111 are measured by using ionization type of dose calibrators. Therapeutic radionuclides, which emit both beta and gamma rays are detected by the same type of dose calibrators. Other therapeutic products like Y-90, P-32 and Sr-89 are pure beta emitters and they are gaining wider utility because various new therapy radiopharmaceuticals are being developed. The type of container material, like glass or plastic, may seriously affect radioactivity measurement due to attenuation, Since it is crucial to give the exact amount of radioactivity to the patient for therapy purposes, dedicated dose calibrators are specially manufactured for the measurement of these radionuclides. But these measuring systems are not widely available in nuclear medicine centers where therapy is applied to the patient. It is a known fact that dose calibrators routinely used in nuclear medicine departments can be calibrated for vials and syringes using standard sources of the same radioisotope. The method of calibration of Y-90 measurement for two ionization chamber dose calibrators available in the institute will be summarized in this presentation. (author)

Monte Carlo simulation of β-γ coincidence system using plastic scintillators in 4π geometry

International Nuclear Information System (INIS)

Dias, M.S.; Piuvezam-Filho, H.; Baccarelli, A.M.; Takeda, M.N.; Koskinas, M.F.

2007-01-01

A modified version of a Monte Carlo code called Esquema, developed at the Nuclear Metrology Laboratory in IPEN, Sao Paulo, Brazil, has been applied for simulating a 4πβ(PS)-γ coincidence system designed for primary radionuclide standardisation. This system consists of a plastic scintillator in 4π geometry, for alpha or electron detection, coupled to a NaI(Tl) counter for gamma-ray detection. The response curves for monoenergetic electrons and photons have been calculated previously by Penelope code and applied as input data to code Esquema. The latter code simulates all the disintegration processes, from the precursor nucleus to the ground state of the daughter radionuclide. As a result, the curve between the observed disintegration rate as a function of the beta efficiency parameter can be simulated. A least-squares fit between the experimental activity values and the Monte Carlo calculation provided the actual radioactive source activity, without need of conventional extrapolation procedures. Application of this methodology to 60 Co and 133 Ba radioactive sources is presented and showed results in good agreement with a conventional proportional counter 4πβ(PC)-γ coincidence system

Hydrogen bonds between the alpha and beta subunits of the F1-ATPase allow communication between the catalytic site and the interface of the beta catch loop and the gamma subunit.

Science.gov (United States)

Boltz, Kathryn W; Frasch, Wayne D

2006-09-19

F(1)-ATPase mutations in Escherichia coli that changed the strength of hydrogen bonds between the alpha and beta subunits in a location that links the catalytic site to the interface between the beta catch loop and the gamma subunit were examined. Loss of the ability to form the hydrogen bonds involving alphaS337, betaD301, and alphaD335 lowered the k(cat) of ATPase and decreased its susceptibility to Mg(2+)-ADP-AlF(n) inhibition, while mutations that maintain or strengthen these bonds increased the susceptibility to Mg(2+)-ADP-AlF(n) inhibition and lowered the k(cat) of ATPase. These data suggest that hydrogen bonds connecting alphaS337 to betaD301 and betaR323 and connecting alphaD335 to alphaS337 are important to transition state stabilization and catalytic function that may result from the proper alignment of catalytic site residues betaR182 and alphaR376 through the VISIT sequence (alpha344-348). Mutations betaD301E, betaR323K, and alphaR282Q changed the rate-limiting step of the reaction as determined by an isokinetic plot. Hydrophobic mutations of betaR323 decreased the susceptibility to Mg(2+)-ADP-AlF(n)() inhibition and lowered the number of interactions required in the rate-limiting step yet did not affect the k(cat) of ATPase, suggesting that betaR323 is important to transition state formation. The decreased rate of ATP synthase-dependent growth and decreased level of lactate-dependent quenching observed with alphaD335, betaD301, and alphaE283 mutations suggest that these residues may be important to the formation of an alternative set of hydrogen bonds at the interface of the alpha and beta subunits that permits the release of intersubunit bonds upon the binding of ATP, allowing gamma rotation in the escapement mechanism.

Effect of the gamma radiation of cobalt 60 on the beta carotids present in the carrot

International Nuclear Information System (INIS)

Perez Lopez, Sergio Victor Hugo

1997-01-01

In the present work it was investigated the effect of the gamma radiation of cobalt 60 on the beta carotid's in the carrot (daucus carota), using for it three different radiation dose (100, 150 and 200 kilo-rad) and analyzing them by means of the liquid chromatography technique of high resolution (HPLC)

{gamma} decay of spin-isospin states in {sup 13}N via ({sup 3}He, t{gamma}) reaction

Energy Technology Data Exchange (ETDEWEB)

Ihara, F; Akimune, H; Daito, I; Fujimura, H; Fujiwara, M; Inomata, T; Ishibashi, K; Yoshida, H [Osaka Univ., Ibaraki (Japan). Research Center for Nuclear Physics; Fujita, Y

1998-03-01

Spin-isospin states in {sup 13}N have been studied by means of the {sup 13}C ({sup 3}He,t) reaction at and near zero degree, at E({sup 3}He)=450 MeV. Decayed {gamma}-rays from each state were measured at backward angle in coincidence with the ejectile tritons. The branching ratio of {gamma} decay for some of spin-isospin states were determined and were compared to those from previous data. (author)

Calculation of coincidence summing corrections for a specific small soil sample geometry

Energy Technology Data Exchange (ETDEWEB)

Helmer, R.G.; Gehrke, R.J.

1996-10-01

Previously, a system was developed at the INEL for measuring the {gamma}-ray emitting nuclides in small soil samples for the purpose of environmental monitoring. These samples were counted close to a {approx}20% Ge detector and, therefore, it was necessary to take into account the coincidence summing that occurs for some nuclides. In order to improve the technical basis for the coincidence summing corrections, the authors have carried out a study of the variation in the coincidence summing probability with position within the sample volume. A Monte Carlo electron and photon transport code (CYLTRAN) was used to compute peak and total efficiencies for various photon energies from 30 to 2,000 keV at 30 points throughout the sample volume. The geometry for these calculations included the various components of the detector and source along with the shielding. The associated coincidence summing corrections were computed at these 30 positions in the sample volume and then averaged for the whole source. The influence of the soil and the detector shielding on the efficiencies was investigated.

The decay of 93Rb

International Nuclear Information System (INIS)

Mitamura, Tohru; Hiromura, Kazuyuki; Aoki, Kazuhiko; Sekioka, Tsuguhisa; Matsui, Hiroshi; Okano, Kotoyuki; Kawase, Yoichi.

1987-01-01

The isotope mass separator installed at the Research Reactor Institute of Kyoto University (KUR-ISOL) is used to separate 93 Rb (half-life 5.85 sec.) resulting from fission of 235 U and the levels in its daughter nuclide, 93 Sr, resulting from its decay is examined by means of nuclear spectrometric measurements including Eγ, Iγ, γ-γ coincidence and conversion electron observation. Analysis of gamma-ray spectra obtained identifies a total of 241 gamma-ray peaks including those found only in coincidence spectra. The γ-γ measurements are analyzed in relation to 21 gamma-ray gates selected. For each coincident gamma-ray peak in coincidence of the gate gamma-rays, the ratio of its area in the γ-γ coincidence spectrum to that in the singles spectrum is determined. By examining the ratio, it is possible in most cases to determine whether coincident gamma-rays are directly related with those selected as the gates or indirectly related with them. A decay diagram is constructed based on the relations in energy, intensity and coincidence among these gamma-rays. Results obtained demonstrate a high reliability of the method employed in this study. Conversion electron spectrometry is carried out using an Si(Li) and a Ge(Li) detector in combination with a plastic scintillator for beta-ray detection. Analysis of the results has not yet been completed. Some findings are briefly outlined. (Nogami, K.)

Simultaneous and separate, low background counting of beta rays and gamma rays using the phoswich principle

International Nuclear Information System (INIS)

Mayhugh, M.R.; Utts, B.K.; Shoffner, B.M.

1978-01-01

A phoswich constructed using thin calcium fluoride optically coupled to a thicker sodium iodide crystal and operated with pulse shape analysis equipment can be used as an efficient low background counting assembly. Low background in the beta ray counting channel is achieved by judicious choice of pure materials in the assembly and by operating the analysis equipment so as to reject background events which occur simultaneously in the sodium iodide crystal. Careful survey of construction materials and methods has resulted in reducing beta ray counting background to 0.6 c/min for a 2-inch diameter assembly. The radioactivity of typical building materials will be discussed. A pulse shape analyzer has been constructed which provides separately adjusted time windows and separate output information for the beta ray and gamma ray channels. The dual channel capability combined with the low beta ray background reduces the sample counting time significantly for typical laboratory samples. (author)

Analysis of (HI, xnγ) coincidence spectra

International Nuclear Information System (INIS)

Pattabiraman, N.S.; Ghugre, S.S.; Chintalapudi, S.N.

2000-01-01

The increase in the sensitivity and the detection limits of the modern third generation gamma detector arrays, has made it necessary to properly understand and estimate the observed background in such experiments. The present paper extends the two algorithms to improve the genuine photo-peak-photo-peak coincident events of interest

An analytical model to calculate absorbed fractions for internal dosimetry with alpha, beta and gamma emitters

Directory of Open Access Journals (Sweden)

Ernesto Amato

2014-03-01

Full Text Available We developed a general model for the calculation of absorbed fractions in ellipsoidal volumes of soft tissue uniformly filled with alpha, beta and gamma emitting radionuclides. The approach exploited Monte Carlo simulations with the Geant4 code to determine absorbed fractions in ellipsoids characterized by a wide range of dimensions and ellipticities, for monoenergetic emissions of each radiation type. The so-obtained absorbed fractions were put in an analytical relationship with the 'generalized radius', calculated as 3V/S, where V is the ellipsoid volume and S its surface. Radiation-specific parametric functions were obtained in order to calculate the absorbed fraction of a given radiation in a generic ellipsoidal volume. The dose from a generic radionuclide can be calculated through a process of summation and integration over the whole radionuclide emission spectrum, profitably implemented in an electronic spreadsheet. We compared the results of our analytical calculation approach with those obtained from the OLINDA/EXM computer software, finding a good agreement in a wide range of sphere radii, for the high-energy pure beta emitter 90Y, the commonly employed beta-gamma emitter 131I, and the pure alpha emitter 213Po. The generality of our approach makes it useful an easy to implement in clinical dosimetry calculations as well as in radiation safety estimations when doses from internal radionuclide uptake are to be taken into account.

Monte Carlo simulation of activity measurements by means of 4πβ-γ coincidence system

International Nuclear Information System (INIS)

Takeda, Mauro N.; Dias, Mauro S.; Koskinas, Marina F.

2004-01-01

The methodology for simulating all detection processes in a 4πβ-γ coincidence system by means of the Monte Carlo technique is described. The goal is to predict the behavior of the observed activity as a function of the 4πβ detector efficiency. In this approach, the information contained in the decay scheme is used for determining the contribution of all radiations emitted by the selected radionuclide, to the measured spectra by each detector. This simulation yields the shape of the coincidence spectrum, allowing the choice of suitable gamma-ray windows for which the activity can be obtained with maximum accuracy. The simulation can predict a detailed description of the extrapolation curve, mainly in the region where the 4πβ detector efficiency approaches 100%, which is experimentally unreachable due to self absorption of low energy electrons in the radioactive source substrate. The theoretical work is being developed with MCNP Monte Carlo code, applied to a gas-flow proportional counter of 4π geometry, coupled to a pair of NaI(Tl) crystals. The calculated efficiencies are compared to experimental results. The extrapolation curve can be obtained by means of another Monte Carlo algorithm, being developed in the present work, to take into account fundamental characteristics of a complex decay scheme, including different types of radiation and transitions. The present paper shows preliminary calculated values obtained by the simulation and compared to predicted analytical values for a simple decay scheme. (author)

Near stellar sources of gamma-ray bursts

OpenAIRE

Luchkov, B. I.; Markin, P. D.

2012-01-01

Correlation analysis of gamma-ray burst coordinates and nearby stars, registered on 2008-2011, revealed 5 coincidences with angular accuracy better than 0.1 degree. The random probability is $7\\times 10^{-7}$, so evidencing that coincident stars are indeed gamma-ray burst sources. The proposed method should be continued in order to provide their share in common balance of cosmic gamma-ray bursts.

An easy and efficient method to produce {gamma}-amino alcohols by reduction of {beta}-enamino ketones

Energy Technology Data Exchange (ETDEWEB)

Harris, Maria Ines N.C.; Braga, Antonio C.H. [Universidade Estadual de Campinas, SP (Brazil). Inst. de Quimica]. E-mail: herrera@iqm.unicamp.br

2004-12-01

Reduction of {beta}-enamino ketones 2 with NaBH{sub 4} in glacial acetic acid gave {gamma}-amino alcohols 1 in 70% to 98% yield with diastereomeric excesses, preferentially the syn product, from 44% to 90%. The stereochemistry of these compounds was confirmed by analysis of their tetrahydro-1,3-oxazine derivatives 3. (author)

Parapapillary atrophy: histological gamma zone and delta zone.

Directory of Open Access Journals (Sweden)

Jost B Jonas

Full Text Available BACKGROUND: To examine histomorphometrically the parapapillary region in human eyes. METHODOLOGY/PRINCIPAL FINDINGS: The histomorphometric study included 65 human globes (axial length:21-37 mm. On anterior-posterior histological sections, we measured the distance Bruch's membrane end (BME-optic nerve margin ("Gamma zone", BME-retinal pigment epithelium (RPE ("Beta zone", BME-beginning of non-occluded choriocapillaris, and BME-beginning of photoreceptor layer. "Delta zone" was defined as part of gamma zone in which blood vessels of at least 50 µm diameter were not present over a length of >300 µm. Beta zone (mean length:0.35±0.52 mm was significantly (P = 0.01 larger in the glaucoma group than in the non-glaucomatous group. It was not significantly (P = 0.28 associated with axial length. Beta zone was significantly (P = 0.004 larger than the region with occluded choriocapillaris. Gamma zone (mean length:0.63±1.25 mm was associated with axial length (P50 µm diameter within gamma zone was present only in highly axially elongated globes and was not related with glaucoma. Beta zone (Bruch's membrane without RPE was correlated with glaucoma but not with globe elongation. Since the region with occluded choriocapillaris was smaller than beta zone, complete loss of RPE may have occurred before complete choriocapillaris closure.

Beta-decay of {sup 103}In: evidence for the Gamow-Teller resonance near {sup 100}Sn

Energy Technology Data Exchange (ETDEWEB)

Karny, M. [Warsaw Univ. (Poland). Inst. of Experimental Physics; Batist, L.; Brown, B.A. [and others

1998-04-01

The {beta} decay of the neutron-deficient isotope {sup 103}In was investigated by using total absorption {gamma}-ray spectrometry on mass-separated sources. The measurement reveals a high-lying resonance of the {beta}-decay strength in striking disagreement with high-resolution {gamma}-ray data. The result is discussed in comparison with shell-model predictions. (orig.)

Fast-timing studies of nuclei below $^{68}$Ni populated in the $\\beta$-decay of Mn isotopes

CERN Multimedia

Jokinen, A; Simpson, G S; Garcia borge, M J; Koester, U H; Georgiev, G P; Fraile prieto, L M; Aprahamian, A

2008-01-01

We intend to investigate structure of nuclei populated in the $\\beta$-decay of Mn isotopes via the ATD $\\beta\\gamma\\gamma$(t) technique. With this method we will measure dynamic moments in Fe isotopes and their daughters in order to characterize the role of particle-hole excitation across the ${N}$=40 sub-shell closure and the development of collectivity.

Line C17: alpha and medium-level beta-gamma laboratory pilot facility

International Nuclear Information System (INIS)

Calor, J.N.; Mauborgne, B.; Montuir, M.

2000-01-01

The Process Development Laboratory (LDP) uses the ATALANTE C17 line for integral testing in order to develop and validate spent fuel reprocessing methods and for overall qualification of calculation codes. Line C 17 comprises shielded cells and glove boxes, equipped with centrifugal extractors and laboratory-scale mixer-settlers to test liquid-liquid extraction processes in an alpha and medium-level beta-gamma environment. The high reliability and precision of the process instrumentation and control system allow full control of operating parameters and comprehensive operating data recording, meeting the experimentation quality requirements necessary for qualifying calculation codes. Direct online spectrophotometric analysis at various points in the process provides real-time concentration data for vital elements, some of which are difficult to analyze offline because of their poor chemical stability. Online analyses, supplemented when necessary by gamma spectrometry, provide valuable process control input for reaching stabilized operating conditions. Fifteen radioactive test campaigns have been successfully completed since line C 17 was commissioned in June 1995. (authors)

Differential expression of gamma-tubulin and class III beta-tubulin in medulloblastomas and human medulloblastoma cell lines

Czech Academy of Sciences Publication Activity Database

Caracciolo, V.; D´Agostino, L.; Dráberová, Eduarda; Sládková, Vladimíra; Crozier-Fitzgerald, C.; Agamanolis, D.P.; De Chadarévian, J.P.; Legido, A.; Giordano, A.; Dráber, Pavel; Katsetos, C.D.

2010-01-01

Roč. 223, č. 2 (2010), s. 519-529 ISSN 0021-9541 R&D Projects: GA AV ČR KAN200520701 Institutional research plan: CEZ:AV0Z50520514 Keywords : gamma-tubulin * beta III-tubulin * meduloblastoma Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.986, year: 2010

Development of a 'chronotron' for time of flight fast neutron spectrometer; Realisation d'un chronotron pour spectrometre a neutrons rapides par temps de vol

Energy Technology Data Exchange (ETDEWEB)

Duclos, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1958-10-15

A chronotron using storage circuits of a 100 channels amplitude analyser has been developed in order to measure the time of flight of fast neutrons. A time dilatation is obtained by a distribution of 20 6BN6 tubes. The width at half maximum of prompt coincidences curve is 1,6.10{sup -9} s for {beta}-{gamma} coincidences from An{sup 198} and 2.10{sup -9} s for n-{alpha} coincidences from (d, t) reaction. (author) [French] En vue de realiser un spectrometre a neutrons rapides par temps de vol, un chronotron utilisant les circuits d'enregistrement d'un selecteur d'amplitude de 100 canaux a ete construit. Une dilatation du temps est obtenue a l'aide d'une distribution de 20 lampes 6BN6. La largeur a mi-hauteur de la courbe de resolution est 1,6.10{sup -9} s pour les coincidences {beta}-{gamma} de Au{sup 198} et 2.10{sup -9} s pour les coincidences n-{alpha} de la reaction (d, t). (auteur)

A new extremity dosemeter for beta and gamma radiation

International Nuclear Information System (INIS)

Heinzelmann, M.; Pagenkamper, M.

1988-01-01

An extremity dosemeter developed at the Juelich Nuclear Research Centre is very well suited for the precise and energy-independent measurement of the skin dose generated by beta or gamma radiation. This is also confirmed by the results of this intercomparison programme. The dosemeter contains three TLDs of LiF in Teflon mounted behind a window of 0.9 mg/cm 2 . The great advantage of this dosemeter is three TLD's enabling statements about the radiation quality. However, the dosemeter has two disadvantages The dosemeter is complicated to manufacture. A very thin plastic foil of 0.9 mg/cm 2 must be attached to a support. This work is difficult and time-consuming and cannot be automated. The window in front of the TLD is not sturdy enough and is occasionally destroyed when the dosemeter is being worn. These two disadvantages prevent this extremity dosemeter from being used more frequently. For this reason, work was begun on developing a new extremity dosemeter without these two disadvantages. The great advantage of the previous dosemeter of obtaining statements about the type of radiation with the aid of readings from three TLD's was to be retained. The improved extremity dosemeter has a more sturdy and thicker window with a similar response as the previous dosemeter with a thinner window