Very large area multiwire spectroscopic proportional counters

International Nuclear Information System (INIS)

Ubertini, P.; Bazzano, A.; Boccaccini, L.; Mastropietro, M.; La Padula, C.D.; Patriarca, R.; Polcaro, V.F.

1981-01-01

As a result of a five year development program, a final prototype of a Very Large Area Spectroscopic Proportional Counter (VLASPC), to be employed in space borne payloads, was produced at the Istituto di Astrofisica Spaziale, Frascati. The instrument is the last version of a new generation of Multiwire Spectroscopic Proportional Counters (MWSPC) succesfully employed in many balloon borne flights, devoted to hard X-ray astronomy. The sensitive area of this standard unit is 2700 cm 2 with an efficiency higher than 10% in the range 15-180 keV (80% at 60 keV). The low cost and weight make this new type of VLASPC competitive with Nal arrays, phoswich and GSPC detectors in terms of achievable scientific results. (orig.)

Very large area multiwire spectroscopic proportional counters

Energy Technology Data Exchange (ETDEWEB)

Ubertini, P.; Bazzano, A.; Boccaccini, L.; Mastropietro, M.; La Padula, C.D.; Patriarca, R.; Polcaro, V.F. (Istituto di Astrofisica Spaziale, Frascati (Italy))

1981-07-01

As a result of a five year development program, a final prototype of a Very Large Area Spectroscopic Proportional Counter (VLASPC), to be employed in space borne payloads, was produced at the Istituto di Astrofisica Spaziale, Frascati. The instrument is the last version of a new generation of Multiwire Spectroscopic Proportional Counters (MWSPC) successfully employed in many balloon borne flights, devoted to hard X-ray astronomy. The sensitive area of this standard unit is 2700 cm/sup 2/ with an efficiency higher than 10% in the range 15-180 keV (80% at 60 keV). The low cost and weight make this new type of VLASPC competitive with Nal arrays, phoswich and GSPC detectors in terms of achievable scientific results.

An integrated photosensor readout for gas proportional scintillation counters

International Nuclear Information System (INIS)

Lopes, J.A.M.; Santos, J.M.F. dos; Conde, C.A.N.

1996-01-01

A xenon gas proportional scintillation counter has been instrumented with a novel photosensor that replaces the photomultiplier tube normally used to detect the VUV secondary scintillation light. In this implementation, the collection grid of a planar gas proportional scintillation counter also functions as a multiwire proportional chamber to amplify and detect the photoelectrons emitted by a reflective CsI photocathode in direct contact with the xenon gas. This integrated concept combines greater simplicity, compactness, and ruggedness (no optical window is used) with low power consumption. An energy resolution of 12% was obtained for 59.6 keV x-rays

New proportional counter assembly in Gliwice 14C laboratory

International Nuclear Information System (INIS)

Moscicki, W.; Zastawny, A.

1977-01-01

The design and parameters are described of a proportional counter for low level counting. The cathode tube 80 mm in diameter and 30 cm in length is made of pure copper. The anode is a tungsten wire 0.05 mm in diameter. The cathode tube is surrounded by a cylindrical ring container with mercury. The total volume of the counter is 1.5 l and it is filled with carbon dioxide. At a pressure of 1 at of CO 2 the counter background is 4.20+-0.05 cpm and contemporary 14 C net effect 10.22+-0.10 cpm; at a pressure of 2 at of CO 2 the background is 4.40+-0.05 cpm and the contemporary 14 C net effect 20.53+-10 cpm. The efficiency of the proportional counter is 88% in both cases. (J.B.)

Calibration of proportional counters in microdosimetry

International Nuclear Information System (INIS)

Varma, M.N.

1982-01-01

Many microdosimetric spectra for low LET as well as high LET radiations are measured using commercially available (similar to EG and G) Rossi proportional counters. This paper discusses the corrections to be applied to data when calibration of the counter is made using one type of radiation, and then the counter is used in a different radiation field. The principal correction factor is due to differences in W-value of the radiation used for calibration and the radiation for which microdosimetric measurements are made. Both propane and methane base tissue-equivalent (TE) gases are used in these counters. When calibrating the detectors, it is important to use the correct stopping power value for that gas. Deviations in y-bar/sub F/ and y-bar/sub D/ are calculated for 60 Co using different extrapolation procedures from 0.15 keV/μm to zero event size. These deviations can be as large as 30%. Advantages of reporting microdosimetric parameters such as y-bar/sub F/ and y-bar/sub D/ above a certain minimum cut-off are discussed

Multi-element proportional counter for radiation protection measurements

International Nuclear Information System (INIS)

Kliauga, P.; Rossi, H.H.; Johnson, G.

1988-01-01

This article discusses design modifications of a multi-element proportional counter. The original counter exhibited poor resolution, as measured by the width of the event-size spectrum for low-energy photons. It was also suspected that the field inside each volume was not sufficiently symmetric. Results of the modifications showed that a dramatic improvement in resolution could be obtained in the chamber with tissue-equivalent septa if their potentials were adjusted to obtain optimal resolution. The full width at half maximum then approached, although it did not equal, that of a standard spherical counter

Gas scintillation proportional counters for x-ray synchrotron applications

International Nuclear Information System (INIS)

Smith, A.; Bavdaz, M.

1992-01-01

Gas scintillation proportional counters (GSPCs) as x-ray detectors provide some advantages and disadvantages compared with proportional counters. In this paper the various configurations of xenon filled GSPC are described including both imaging and nonimaging devices. It is intended that this work be used to configure a GSPC for a particular application and predict its general performance characteristics. The general principles of operation are described and the performance characteristics are then separately considered. A high performance, imaging, driftless GSPC is described in which a single intermediate window is used between the PMT and gas cell

On timing properties of the SRPO-304 proportional counters

International Nuclear Information System (INIS)

Gusev, A.A.; Pugacheva, G.I.

1979-01-01

Data of measurements of the signal delay time and the time of development of the discharge in a proportional counter filled with 90% Xe + 10% CH 4 mixture at 0.3 atm are presented. The measurements were carried out on muons of cosmic rays. Signal delay distribution for the proportional counter are given relative to the time of passage through it of a charged particle. The data obtained shows that the average delay time is 0.8 μs when a particle passes near the counter centre, whereas when it passes near its side wall the average delay time is 1.5 μs. The investigation of the discharge development time distribution was carried out for two values of the discriminator threshold: 6 and 20 keV. It was determined that the discharge development time distribution depends but little on the place of particle passage in a counter. The average discharge development time is 1.5 μs, with the maximum time beina 4.3 μs. It is shown that the resolution time of logical circuits will be near 4 μs when the counter is combined with scintillation detectors

Proportional counter with a wire-anode lying on the dielectric surface

International Nuclear Information System (INIS)

Strelkov, A.V.

1983-01-01

Proportional coUnter with wire-anode lying on the dielectric surface is described. The result of the accumulation of charges on the dielectric surface immediately near the wire-anode surface is that such a counter possesses electrostatic memory relative to distribution of the gas amplification coefficient along the anode. SUch a distribution can be received for example by means of irradiation by the neutrons or the γ-rays. The disposition of the wire-anode on the convex dielectric surface allows one to make the ring-shaped counters or the nonplane proportional chambers practically of any profile. However, the energy resolution of the counter with anode on the dielectric is worse than the resolution of counter with free anode particularly at the large gas amplification coefficient

A proportional counter for efficient backscatter Moessbauer effect spectroscopy

International Nuclear Information System (INIS)

Pawlowski, Z.; Marzec, J.; Cudny, W.; Holnicka, J.; Walentek, J.

1979-01-01

The authors present a novel gas-tight proportional counter with flat beryllium windows for backscatter Moessbauer spectroscopy. The krypton-filled counter has a geometry that approaches 2π and a resolution of 12% fwhm for the 14.4 keV line of 57 Fe, and is easy to manufacture. (Auth.)

Pulse triggering mechanism of air proportional counters

International Nuclear Information System (INIS)

Aoyama, T.; Mori, T.; Watanabe, T.

1983-01-01

This paper describes the pulse triggering mechanism of a cylindrical proportional counter filled with air at atmospheric pressure for the incidence of β-rays. Experimental results indicate that primary electrons created distantly from the anode wire by a β-ray are transformed into negative ions, which then detach electrons close to the anode wire and generate electron avalanches thus triggering pulses, while electrons created near the anode wire by a β-ray directly trigger a pulse. Since a negative ion pulse is triggered by a single electron detached from a negative ion, multiple pulses are generated by a large number of ions produced by the incidence of a single β-ray. It is therefore necessary not to count pulses triggered by negative ions but to count those by primary electrons alone when use is made of air proportional counters for the detection of β-rays. (orig.)

Position-sensitive proportional counters using resistance-capacitance position encoding

International Nuclear Information System (INIS)

Kopp, M.K.; Borkowski, C.J.

1975-12-01

A new method was developed for encoding the position of individual photons, neutrons, or charged particles in proportional counters by using the distributed RC line characteristics of these counters. The signal processing is described and guidelines for the design and operation of these position sensitive proportional counters (PSPCs) are given. Using these guidelines, several prototypic PSPCs were constructed to improve the spatial resolution and shorten the signal processing time; for example, the intrinsic spatial uncertainty was reduced to 28 μ fwhm for alpha particles and 100 μ fwhm for low-energy x rays (2 to 6 keV). Also, the signal processing time was reduced to 0.6 μsec without seriously degrading the spatial resolution. These results have opened new fields of application of the RC position encoding method in imaging distributions of photons, charged particles, or neutrons in nuclear medicine, physics, and radiography

The background of external γ radiation in the proportional counters in SAGE experiment

International Nuclear Information System (INIS)

Gavrin, V.N.; Gorbachev, V.V.

2003-01-01

The influence of external γ radiation on the process of 71 Ge-decay counting in proportional counters in SAGE experiment of solar neutrino flux measurement is examined. One determines the systematic error of SAGE result, connected with radon decays inside the air volume surrounding the counters, and the background counting rate of proportional counters from γ radiation of passive and active shield [ru

Space-charge effects of the proportional counters in a multiple-ionization chamber

International Nuclear Information System (INIS)

Mang, M.

1993-01-01

At the ALADIN spectrometer of the GSI in october 1991 for the first time the new multiple ionization chamber was applied, in the two anode planes of which are additional multiwire-proportional counters. The proportional counters are required in order to make the detection of light fragments (Z 4 gold projectiles per second by these positive space charges the homogeneous electric field of the MUSIC is disturbed. This effect is especially strong in the beam plane. As consequence of the space charge additionally electrons are focused on the proportional counter so that their amplitudes in dependence on the beam intensity increase up to the 2.5-fold. Furthermore the y coordinate is falsified, because the electrons are diverted to the medium plane. On the measurement of the x coordinate this diversion has with maximally 0.1% only a small influence. These space-charge effects can be qualitatively described by a schematic model, which assumes a stationary positive space charge. Additionally for the proportional counters, which are not in the beam plane, their resolution was determined. In these counters the space-charge effects are small, because essentially fewer particles are registrated than in the medium MWPC's. By this charges of fragments with Z<10 could be separated. The charge resolution amounted at lithium 0.8 charge units. The position resolution of the proportional counters in y direction was determined to less than 8 mm. The detection probability of the fragments amounts for lithium 90% and from boron all fragments are detected

A nuclear proportional counter

International Nuclear Information System (INIS)

1973-01-01

The invention relates to a nuclear proportional counter comprising in a bulb filled with a low-pressure gas, a wire forming an anode and a cathode, characterized in that said cathode is constituted by two plane plates parallel to each other and to the anode wire, and in that two branches of a circuit are connected to the anode wire end-portions, each branch comprising a pre-amplifier, a measuring circuit consisting of a differentiator-integrator-differentiator amplifier and a zero detector, one of the branches comprising an adjustable delay circuit, both branches jointly attacking a conversion circuit for converting the pulse duration into amplitudes said conversion circuit being followed by a multi-channel analyzer, contingently provided with a recorder [fr

Ideal response function of a 3He proportional counter to thermal neutrons determined by different length counters

International Nuclear Information System (INIS)

Takeda, Naoto; Kudo, Katsuhisa; Kobayashi, Katsuhei; Yoshimoto, Takaaki

2000-01-01

The relative gas multiplication along the cylindrical axis of three 3 He proportional counters with different length were measured by using a thermal neutron beam at the Kyoto University Reactor and an ideal response function by taking into account the difference of pulse height spectra were measured by different length counters. The three 3 He proportional counters (model type of P4-0806, P4-0806 and P4-0808 manufactured by Reuter-Stokes) prepared for relative gas multiplication measurements had identical structure having cylindrical outer shells of 304 stainless steel except for different sensitive lengths of 10 cm, 15 cm and 20 cm, respectively. All counters were filled with 400 kPa of 3 He gas and 200 kPa of Ar gas. The pulse height distributions were measured by moving the counter in the direction of it's cylindrical axis perpendicular to the thermal neutron beam. The measured pulse heights corresponding to the full energy peaks at various entrance points were normalized to that of the whole counter irradiation. The results as a function of the distance from the bottom edge of the stainless steel cylinder are shown. The total transition region of gas gain corresponded to about 23 %, 15 % and 10 % of each nominal sensitive region corresponding to shot, middle and long counters. The ideal pulse height spectrum (dots) obtained by using proportional counters of 10 cm and 20 cm in nominal sensitive length to thermal neutron beam is shown in the paper in comparison to simulated one which was calculated assuming the constant gain within the sensitive region and zero gas gain outside the sensitive regions. The simulation realized the ideal response function fairly well. (S.Y.)

Background of external γ radiation in the proportional counters of the SAGE experiment

International Nuclear Information System (INIS)

Gavrin, V.N.; Gorbachev, V.V.

2003-01-01

The effect of external γ radiation on the process of counting 71 Ge decays in the proportional counters of the SAGE experiment measuring the solar-neutrino flux is considered. The systematic uncertainty in the SAGE result due to radon decays inside the air volume surrounding the counters is estimated. The background counting rate in the proportional counters that is caused by γ radiation from the enclosing shield is also determined

Pulse-shape discrimination in IAEA tritium proportional counters

International Nuclear Information System (INIS)

Florkowski, T.

1981-01-01

Two systems of pulse-shape discrimination (PSD) for the reduction of background in low-level proportional counters were tested. A tentative conclusion is drawn that both PSD systems, although they decrease slightly the meson background, do not bring improvement in the analytical accuracy

Performance of microstrip proportional counters for x-ray astronomy on spectrum-roentgen-gamma

DEFF Research Database (Denmark)

Budtz-Jørgensen, Carl; BAHNSEN, A; Christensen, Finn Erland

1991-01-01

DSRI will provide a set of four imaging proportional counters for the Danish-Soviet X-ray telescopes XSPECT/SODART. The sensor principle is based on the novel micro-strip proportional counter (MSPC), where the strip electrodes are deposited by photolithography onto a rigid substrate. The MSPC off...

Novel concept for neutron detection: proportional counter filled with 10B nanoparticle aerosol

Science.gov (United States)

Amaro, F. D.; Monteiro, C. M. B.; dos Santos, J. M. F.; Antognini, A.

2017-01-01

The high neutron detection efficiency, good gamma-ray discrimination and non-toxicity of 3He made of proportional counters filled with this gas the obvious choice for neutron detection, particularly in radiation portal monitors (RPM), used to control the illicit transport of nuclear material, of which neutron detectors are key components. 3He is very rare and during the last decade this gas has become increasingly difficult to acquire. With the exception of BF3, which is toxic, no other gas can be used for neutron detection in proportional counters. We present an alternative where the 3He atoms are replaced by nanoparticles made of another neutron sensitive material, 10B. The particles are dispersed in a gaseous volume, forming an aerosol with neutron sensitive properties. A proportional counter filled with such aerosol was exposed to a thermal neutron beam and the recorded response indicates that the neutrons have interacted with the particles in the aerosol. This original technique, which transforms a standard proportional gas mixture into a neutron sensitive aerosol, is a breakthrough in the field of radiation detection and has the potential to become an alternative to the use of 3He in proportional counters. PMID:28181520

Digital signal processing for 3He proportional counters

International Nuclear Information System (INIS)

Takahashi, Hiroyuki; Kawarabayashi, Jun; Kurahashi, Tomohiko; Iguchi, Tetsuo; Nakazawa, Masaharu

1994-01-01

Numerical analysis of individual pulses from 3 He proportional counters has been performed. A parametric approach has been used for the identification of a charge particle track direction. Using area parameters, a clear separation of events was observed for the wall effect on a triton and a proton, respectively. ((orig.))

Position-sensitive proportional counter with low-resistance metal-wire anode

International Nuclear Information System (INIS)

Kopp, M.K.

1980-01-01

A position-sensitive proportional counter circuit is provided which uses a conventional (low-resistance, metal-wire anode) proportional counter for spatial resolution of an ionizing event along the anode of the counther. A pair of specially designed activecapacitance preamplifiers terminate the anode ends wherein the anode is treated as an RC line. The preamplifiers act as stabilized active capacitance loads and each is composed of a series-feedback, lownoise amplifier, a unity-gain, shunt-feedback amplifier whose output is connected through a feedback capacitor to the series-feedback amplifier input. The stabilized capacitance loading of the anode allows distributed RC-line position encoding and subsequent time difference decoding by sensing the difference in rise times of pulses at te anode ends where the difference is primarily in response to the distributed capacitance along the anode. This allows the use of lower resistance wire anodes for spatial radiation detection which simplifies the counter construction and handling of the anodes, and stabilizes the anode resistivity at high count rates

Proportional counter response calculations for gallium solar neutrino detectors

International Nuclear Information System (INIS)

Kouzes, R.T.; Reynolds, D.

1989-01-01

Gallium bases solar neutrino detectors are sensitive to the primary pp reaction in the sun. Two experiments using gallium, SAGE in the Soviet Union and GALLEX in Europe, are under construction and will produce data by 1989. The radioactive /sup 71/Ge produced by neutrinos interacting with the gallium detector material, is chemically extracted and counted in miniature proportional counters. A number of calculations have been carried out to simulate the response of these counters to the decay of /sup 71/Ge and to background events

On the counting rate-dependent amplitude shifts in proportional counters

International Nuclear Information System (INIS)

Mahesh, K.

1976-01-01

The presence of a positive ion cloud near the anode wire, which has been believed to be the cause of the observed counting rate-dependent peak shifts in proportional counters, does not explain various exhibited features of these shifts. The possibility of other mechanisms involved is, therefore, examined. The columnar recombination of primary ions in the counter is considered to explain the origin of the shifts and their observed features. (Auth.)

Proportional Counter Calibration and Analysis for 12C + p Resonance Scattering

Science.gov (United States)

Nelson, Austin; Rogachev, Grigory; Uberseder, Ethan; Hooker, Josh; Koshchiy, Yevgen

2014-09-01

Light exotic nuclei provide a unique opportunity to test the predictions of modern ab initio theoretical calculations near the drip line. In ab initio approaches, nuclear structure is described starting from bare nucleon-nucleon and three-nucleon interactions. Calculations are very heavy and can only be performed for the lightest nuclei (A objective of this project was to test the performance and perform position calibration of this proportional counter array. The test was done using 12C beam. The excitation function for 12C + p elastic scattering was measured and calibration of the proportional counter was performed using known resonances in 13N. The method of calibration, including solid angle calculations, normalization corrections, and position calibration will be presented. Light exotic nuclei provide a unique opportunity to test the predictions of modern ab initio theoretical calculations near the drip line. In ab initio approaches, nuclear structure is described starting from bare nucleon-nucleon and three-nucleon interactions. Calculations are very heavy and can only be performed for the lightest nuclei (A objective of this project was to test the performance and perform position calibration of this proportional counter array. The test was done using 12C beam. The excitation function for 12C + p elastic scattering was measured and calibration of the proportional counter was performed using known resonances in 13N. The method of calibration, including solid angle calculations, normalization corrections, and position calibration will be presented. Funded by DOE and NSF-REU Program; Grant No. PHY-1263281.

Proportional counter with uniform electric field with Penning's mixture

International Nuclear Information System (INIS)

Pawlowski, Z.; Marzec, J.; Zaremba, K.

1984-01-01

Some calculations are given and the design of proportional counters with a homogeneous electric field filled with Penning's mixtures, which ensure the best energy resolution is described. The counters with mixtures of Ne+Ar, Ne+CH 4 , Ne+CO 2 and Ar+C 2 H 2 have been checked. The admixtures (Ar, CH 4 , CO 2 , C 2 H 2 ) constitute from 0.1 to 2%, with pressure from 125 Tr to 760 Torr. The best energy resolution has been obtained for the mixture of Ne+1%CH 4 at the pressure of 190 Torr

Nitrogen large area proportional counter with gas regeneration

International Nuclear Information System (INIS)

Leidner, L.; Sadri, E.

1984-10-01

A nitrogen large area proportional chamber with gas regeneration is introduced to measure alpha and beta/gamma activites. In contrast to the flow counters used till now the new detector is independent of an external gas supply. The gas amplification factor of nitrogen keeps constant up to an impurity of 2% of O 2 . Oxygen diffusing through unavoidable leakages into the counting gas is removed by an activated catalyzer using low temperature copper oxidation. Humidty is adsorbed by a molecular sieve. The closed counter consists of three components: the actual detector, a gas purification cartridge and a gas circulating pump. Finally, the report describes long run experiments being carried out with prototypes. (orig./HP) [de

Improving the performance of X-ray proportional counters by using field transistor preamplifiers

International Nuclear Information System (INIS)

Kalinina, N.I.; Mel'ttser, L.V.; Pan'kin, V.V.

1972-01-01

The possibility of using low-noise field-effect transistors with the n-channel in preamplifiers for x-ray proportional counters constitutes the object of this article. The operation of the preamplifier assembled according to the scheme of the voltage amplifier and charge-sensitive preamplifier has been studied. The use of the field-effect transistor with the n-channel in preamplifiers for proportional counters allows to improve significantly the energy resolution and operation at reduced voltage and at high loads. Notably good results have been obtained when constructing the circuit of the premplifier with the field-effect transistor on the charge-sensitive principle. The use of home-produced field-effect transistors makes it possible to construct detectors of roentgen radiometric instruments to measure light element content with proportional counters at reduced voltage

Avalanche localization and its effects in proportional counters

International Nuclear Information System (INIS)

Fischer, J.; Okuno, H.; Walenta, A.H.

1977-11-01

Avalanche development around the anode wire in a gas proportional counter is investigated. In the region of proportional gas amplification, the avalanche is found to be well localized on one side of the anode wire, where the electrons arrive along the field lines from the point of primary ionization. Induced signals on electrodes surrounding the anode wire are used to measure the azimuthal position of the avalanche on the anode wire. Practical applications of the phenomena such as left-right assignment in drift chambers and measurement of the angular direction of the primary ionization electrons drifting towards the anode wire are discussed

Energy resolution limitations in a gas scintillation proportional counter

International Nuclear Information System (INIS)

Simons, D.G.; de Korte, P.A.J.; Peacock, A.; Bleeker, J.A.M.

1985-01-01

An investigation is made of the factors limiting the energy resolution of a gas scintillation proportional counter (GSPC). Several of these limitations originate in the drift region of such a counter and data is presented, giving a quantitative description of those effects. Data is also presented of a GSPC without a drift region, that therefore largely circumvents most of those degrading factors. The results obtained so far indicate that in that detector the limitation to the resolution is most probably due to cleanliness of the gas. Further research is underway in order to assess quantitatively the limiting factors in such a driftless GSPC

Methods of calculus for neutron spectrometry in proportional counters

International Nuclear Information System (INIS)

Butragueno, J.L.; Blazquez, J.B.; Barrado, J.M.

1976-01-01

Response functions for cylindrical proportional counters with hidrogenated gases have been determined, taking in account only wall effect, by means of two independent calculus methods. One of them is a Montecarlo application and the other one analytical at all. Results of both methods have been compared. (author) [es

Methods of calculus for neutron spectrometry in proportional counters

International Nuclear Information System (INIS)

Butragueno Casado, J.L.; Blazquez Martinez, J.B.; Barrado Menendez, J.M.

1976-01-01

Response functions for cylindrical proportional counters with hydrogenated gases have been determined, taking in account only wall effect, by means of two independent calculus methods. One of them is a Monte Carlo application and the other one analytica at all. Results of both methods have been compared. (Author)

Design of a hybrid gas proportional counter with CdTe guard counters for sup 1 sup 4 C dating system

CERN Document Server

Zhang, L; Hinamoto, N; Nakazawa, M; Yoshida, K

2002-01-01

Nowadays uniform, low-cost and large-size compound semiconductor detectors are available up to several square centimeters. We are trying to combine this technology with conventional gas detectors to upgrade an anticoincidence type proportional counter, Oeschger-type thin wall counter of 2.2 l, used for a sup 1 sup 4 C dating facility at the University of Tokyo. In order to increase the ratio of the signal to the background for smaller quantity of samples less than 1 g, an effective approach is to minimize the detector volume at higher gas pressure. However, the anticoincidence function suffers from such a small volume. Therefore we designed a new active wall gas counter of 0.13 l counting volume using CdTe compound semiconductor detectors as the wall of the gas proportional counter to perform anticoincidence. Simulation study showed that at noise thresholds less than 70 keV, the wall counters can reject above 99.8% of events arising from outer gamma rays. Measured noise levels of CdTe detectors were smaller t...

Development of a drift tissue equivalent proportional counter for radiation protection personnel dosimetry

International Nuclear Information System (INIS)

Bordy, J.M.

1992-04-01

A new multicellular geometry for proportional counter has been developed. It is made of several drift regions which are some holes drilled in the cathode in front of anodes wires. The present work is made of 3 parts: 1) A theoretical evaluation of the multicellular counter characteristics: the sensitivity increases by a factor 15 vs the Tinelli Merlin-Gerin counter; the chord length distribution study shows the possibility to use a Dirac function for the dosimetry calculations; a tissue equivalent gas mixture based on argon and propane is designed. 2) The production of a monocellular prototype made of a hole and a needle shaped anode. 3) An experimental study of the prototype electrical characteristics and a computation of the electrical field in the counter. The focalization and the electron drift into the hole, the proportional operating mode are shown. Irradiations in front of photon and neutron sources verify these results

Xenon-based Penning mixtures for proportional counters

International Nuclear Information System (INIS)

Ramsey, B.D.; Agrawal, P.C.; National Aeronautics and Space Administration, Huntsville, AL

1989-01-01

The choice of quench gas can have a significant effect on the gas gain and energy resolution of gas-filed proportional counters. Details are given on the performance obtained with a variety of quench additives of varying ionization potentials for use in xenon-filled systems. It is confirmed that optimum performance is obtained when the ionization potential is closely matched to the first metastable level of xenon (8.3 eV) as is the case with xenon + trimethylamine and xenon + dimethylamine. For these mixtures the Penning effect is at its strongest. (orig.)

Development of proportional counters using photosensitive gases and liquids

International Nuclear Information System (INIS)

Anderson, D.F.

1984-10-01

An introduction to the history and to the principle of operation of wire chambers using photosensitive gases and liquids is presented. Their use as light sensors coupled to Gas Scintillation Proportional Counters and BaF 2 , as well as their use in Cherenkov Ring imaging, is discussed in some detail. 42 references, 21 figures

39Ar/Ar measurements using ultra-low background proportional counters

International Nuclear Information System (INIS)

Hall, Jeter; Aalseth, Craig E.; Bonicalzi, Ricco M.; Brandenberger, Jill M.; Day, Anthony R.; Humble, Paul H.; Mace, Emily K.; Panisko, Mark E.; Seifert, Allen

2016-01-01

Age-dating groundwater and seawater using the 39 Ar/Ar ratio is an important tool to understand water mass-flow rates and mean residence time. Low-background proportional counters developed at Pacific Northwest National Laboratory use mixtures of argon and methane as counting gas. We demonstrate sensitivity to 39 Ar by comparing geological (ancient) argon recovered from a carbon dioxide gas well and commercial argon. The demonstrated sensitivity to the 39 Ar/Ar ratio is sufficient to date water masses as old as 1000 years. - Highlights: • 39 Ar/Ar age dating is important for understanding environmental water migration. • Ultra low background proportional counters have been developed. • 39 Ar is detected in atmospheric argon at a rate of 70.3 counts per day. The demonstrated background is 166 counts per day. • Age dating is possible for water with underground residence time of up to 1000 years.

Calibration methodology for proportional counters applied to yield measurements of a neutron burst

Energy Technology Data Exchange (ETDEWEB)

Tarifeño-Saldivia, Ariel, E-mail: atarifeno@cchen.cl, E-mail: atarisal@gmail.com; Pavez, Cristian; Soto, Leopoldo [Comisión Chilena de Energía Nuclear, Casilla 188-D, Santiago (Chile); Center for Research and Applications in Plasma Physics and Pulsed Power, P4, Santiago (Chile); Departamento de Ciencias Fisicas, Facultad de Ciencias Exactas, Universidad Andres Bello, Republica 220, Santiago (Chile); Mayer, Roberto E. [Instituto Balseiro and Centro Atómico Bariloche, Comisión Nacional de Energía Atómica and Universidad Nacional de Cuyo, San Carlos de Bariloche R8402AGP (Argentina)

2014-01-15

This paper introduces a methodology for the yield measurement of a neutron burst using neutron proportional counters. This methodology is to be applied when single neutron events cannot be resolved in time by nuclear standard electronics, or when a continuous current cannot be measured at the output of the counter. The methodology is based on the calibration of the counter in pulse mode, and the use of a statistical model to estimate the number of detected events from the accumulated charge resulting from the detection of the burst of neutrons. The model is developed and presented in full detail. For the measurement of fast neutron yields generated from plasma focus experiments using a moderated proportional counter, the implementation of the methodology is herein discussed. An experimental verification of the accuracy of the methodology is presented. An improvement of more than one order of magnitude in the accuracy of the detection system is obtained by using this methodology with respect to previous calibration methods.

Calibration methodology for proportional counters applied to yield measurements of a neutron burst

International Nuclear Information System (INIS)

Tarifeño-Saldivia, Ariel; Pavez, Cristian; Soto, Leopoldo; Mayer, Roberto E.

2014-01-01

This paper introduces a methodology for the yield measurement of a neutron burst using neutron proportional counters. This methodology is to be applied when single neutron events cannot be resolved in time by nuclear standard electronics, or when a continuous current cannot be measured at the output of the counter. The methodology is based on the calibration of the counter in pulse mode, and the use of a statistical model to estimate the number of detected events from the accumulated charge resulting from the detection of the burst of neutrons. The model is developed and presented in full detail. For the measurement of fast neutron yields generated from plasma focus experiments using a moderated proportional counter, the implementation of the methodology is herein discussed. An experimental verification of the accuracy of the methodology is presented. An improvement of more than one order of magnitude in the accuracy of the detection system is obtained by using this methodology with respect to previous calibration methods

Absolute measurement of the activity of 222Rn using a proportional counter

International Nuclear Information System (INIS)

Busch, Ingo; Greupner, Heinz; Keyser, Uwe

2002-01-01

A measuring set-up comprising a proportional counter of calculable 222 Rn efficiency and quantifiable active volume (δ V 222 Rn efficiency is determined by computer simulation of the measured α-spectra. The procedures necessary for absolute measurements by means of the counter are described, and the suitability of the counter for absolute measurements of the 222 Rn activity is proved by experiments. Thus, a new method for the realization of the unit of activity of 222 Rn is obtained, which is independent of the unit of activity of 226 Ra

Measurements of electron attachment by oxygen molecule in proportional counter

Energy Technology Data Exchange (ETDEWEB)

Tosaki, M., E-mail: tosaki.mitsuo.3v@kyoto-u.ac.jp [Radioisotope Research Center, Kyoto University, Kyoto 606-8501 (Japan); Kawano, T. [National Institute for Fusion Science, 322-6 Oroshi, Toki 509-5292 (Japan); Isozumi, Y. [Radioisotope Research Center, Kyoto University, Kyoto 606-8501 (Japan)

2013-11-15

We present pulse height measurements for 5-keV Auger electrons from a radioactive {sup 55}Fe source mounted at the inner cathode surface of cylindrical proportional counter, which is operated with CH{sub 4} admixed dry air or N{sub 2}. A clear shift of the pulse height has been observed by varying the amount of the admixtures; the number of electrons, created in the primary ionization by Auger electrons, is decreased by the electron attachment of the admixtures during their drift from the place near the source to the anode wire. The large gas amplification (typically 10{sup 4}) in the secondary ionization of proportional counter makes it possible to investigate a small change in the number of primary electrons. The electron attenuation cross-section of O{sub 2} has been evaluated by analyzing the shifts of the pulse height caused by the electron attachment to dry air and N{sub 2}.

X-ray polarimetry with a conventional gas proportional counter through rise-time analysis

CERN Document Server

Hayashida, K; Tsunemi, H; Torii, K; Murakami, H; Ohno, Y; Tamura, K

1999-01-01

We have performed an experiment on the signal rise time of a Xe gas proportional counter using a polarized X-ray beam of synchrotron orbital radiation with energies from 10 to 40 keV. When the counter anode is perpendicular to the electric vector of the incident X-ray photons, the average rise time becomes significantly longer than that for the parallel case. This indicates that the conventional gas proportional counters are useful for X-ray polarimetry. The moderate modulation contrast of this rise-time polarimeter (M=0.1 for 10 keV X-rays and M=0.35 for 40 keV X-rays), with capability of the simultaneous measuring X-ray energies and the timing, would be useful for applications in X-ray astronomy and in other fields.

Experimental dead time corrections for a linear position-sensitive proportional counter

International Nuclear Information System (INIS)

Yelon, W.B.; Tompson, C.W.; Mildner, D.F.R.; Berliner, R.; Missouri Univ., Columbia

1984-01-01

Two simple counters included in the charge-digitization circuitry of a position-sensitive proportional counter using the charge division method for position encoding have enabled us to determine the dead time losses for the system. An interesting positional dependence of the dead time tau is observed, which agrees with a simple model. The system enables us to correct the experimental data for dead time and to be indifferent to the relatively slow analog-to-digital converters used in the system. (orig.)

Study and construction of an air proportional counter for superficial alpha contamination

International Nuclear Information System (INIS)

Cabral, T.S.

1991-01-01

Some properties of the proportional counters such as the working principle and the process of the gaseous multiplication are presented. Besides that, the project of Multiwire Proportional Counters is shown, which was tested with anodic wires of different diameters and with windows of several thicknesses. Operational characteristics of the detector were determined with the quoted variations. The chamber was normally operated by atmospheric pressure, but there were also made surveys on its behavior with oxygen, nitrogen and mixture of both. The performance of the chamber with a variations of temperature and relative humidity is analysed, because that is one of the biggest problems faced when measure of field are being made with this kind of detector. (author)

Feasibility studies of high-pressure 4π proportional counter for absolute activity measurement

International Nuclear Information System (INIS)

Hino, Y.; Kawada, Y.

1988-01-01

A high-pressure proportional counter system is constructed. The high pressure 4πβ counter system constructed is made of aluminum and is divided into two 2π counters. The gas pressure is controlled with a pressure regulator and very fine leak valves to keep the balance of a stable pressure and constant flow rate. Investigation of characteristics of th counter shows that there is an almost linear relation between voltage and pressure. The linearlity of gas gain of this counter to the electron energies is measured with different gas pressures. Quite good linear gas multiplication is obtained at 0.9 MPa. Another investigation is made of application of to activity measurement of 109 Cd. When the gas pressure is over 0.5 MPa, the proportion of collected conversion electrons to absolute activity comes to a constant value of 96 %. This is quite good agreement with the decay data of 96.4 % conversion electron emission rate. The study indicated many excellent features for activity measurement. Especially the efficiency variation technique is good for automatic data acquisition with a programmable high voltage supplier. Moreover, since it is possible to obtain absolute activity with only one sample, it will be quite useful for limited samples experiments. (N.K.)

Rate dependent image distortions in proportional counters

International Nuclear Information System (INIS)

Trow, M.W.; Bento, A.C.; Smith, A.

1994-01-01

The positional linearity of imaging proportional counters is affected by the intensity distribution of the incident radiation. A mechanism for this effect is described, in which drifting positive ions in the gas produce a distorting electric field which perturbs the trajectories of the primary electrons. In certain cases, the phenomenon causes an apparent improvement of the position resolution. We demonstrate the effect in a detector filled with a xenon-argon-CO 2 mixture. The images obtained are compared with the results of a simulation. If quantitative predictions for a particular detector are required, accurate values of the absolute detector gain, ion mobility and electron drift velocity are needed. ((orig.))

Quench gases for xenon- (and krypton-)filled proportional counters

International Nuclear Information System (INIS)

Ramsey, B.D.; Agrawal, P.C.

1988-01-01

Xenon-filled proportional counters are used extensively in astronomy, particularly in the hard X-ray region. The choice of quench gas can have a significant effect on the operating characteristics of the instrument although the data necessary to make the choice are not easily obtainable. We present results which detail the performance obtained from both cylindrical and parallel field geometries for a wide variety of readily available, ultrahigh or research grade purity, quench gases. (orig.)

Investigation of the Pulse Height Distribution of Boron Trifluoride Proportional Counters

Energy Technology Data Exchange (ETDEWEB)

Andersson, I Oe; Malmskog, S

1962-08-15

The report describes a theoretical and experimental investigation of the factors that determine the pulse height distribution of BF{sub 3}, proportional counters irradiated by thermal neutrons. The branching ratio of the {sup 10}B (n,{alpha}) {sup 7}Li reaction for thermal neutrons has been measured.

Position sensitive proportional counter for measurement of tritium labelled gas movement

International Nuclear Information System (INIS)

Mori, Chizuo; Nakamoto, Makihiko; Uritani, Akira; Watanabe, Tamaki

1984-01-01

A position sensitive proportional counter of a charge division type with a single resistive anode wire was constructed for the measurement of the movement of 3 H labelled gas which is flowing or diffusing in a pipe. The introduction of resistors between the anode wire and pre-amplifiers brought a uniform detection efficiency for 3 H β-rays throughout the counter. The position resolution was 3.1 mm FWHM. Detection efficiency was almost 100% uniformly over about 700 mm in the total anode length of 740 mm. The movement of 3 H labelled gas could be measured effectively. (author)

Study on the neutron dosimetric characteristics of Tissue Equivalent Proportional Counter

Energy Technology Data Exchange (ETDEWEB)

Nunomiya, T.; Kim, E.; Kurosawa, T.; Taniguchi, S.; Nakamura, T. [Tohoku Univ., Sendai (Japan). Cyclotron and Radioisotope Center; Tsujimura, N.; Momose, T.; Shinohara, K. [Japan Nuclear Cycle Development Inst., Environment and Safety Division, Tokai Works, Tokai, Ibaraki (Japan)

1999-03-01

The neutron dosimetric characteristics of TEPC (Tissue Equivalent Proportional Counter) has been investigated under a cooperative study between Tohoku University and JNC since 1997. This TEPC is a spherical, large volume, single-wire proportional counter (the model LETSW-5, manufactured by Far West Technology, Inc.) and filled with a tissue equivalent gas in a spherical detector of the A-150 tissue equivalent plastic. The TEPC can measure the spectra of absorbed dose in LET and easily estimate the tissue equivalent dose to neutron. This report summarizes the dosimetric characteristics of TEPC to the monoenergetic neutrons with energy from 8 keV to 15 MeV. It is found that TEPC can estimate the ambient dose equivalent, H*(10), with an accuracy from 0.9 to 2 to the neutron above 0.25 MeV and TEPC has a good counting efficiency enough to measure neutron doses with low dose rate at the stray neutron fields. (author)

Application of the finite-difference approximation to electrostatic problems in gaseous proportional counters

International Nuclear Information System (INIS)

Waligorski, M.P.R.; Urbanczyk, K.M.

1975-01-01

The basic principles of the finite-difference approximation applied to the solution of electrostatic field distributions in gaseous proportional counters are given. Using this method, complicated two-dimensional electrostatic problems may be solved, taking into account any number of anodes, each with its own radius, and any cathode shape. A general formula for introducing the anode radii into the calculations is derived and a method of obtaining extremely accurate (up to 0.1%) solutions is developed. Several examples of potential and absolute field distributions for single rectangular and multiwire proportional counters are calculated and compared with exact results according to Tomitani, in order to discuss in detail errors of the finite-difference approximation. (author)

Computer simulation of gain fluctuations in proportional counters

International Nuclear Information System (INIS)

Demir, Nelgun; Tapan, . Ilhan

2004-01-01

A computer simulation code has been developed in order to examine the fluctuation in gas amplification in wire proportional counters which are common in detector applications in particle physics experiments. The magnitude of the variance in the gain dominates the statistical portion of the energy resolution. In order to compare simulation and experimental results, the gain and its variation has been calculated numerically for the well known Aleph Inner Tracking Detector geometry. The results show that the bias voltage has a strong influence on the variance in the gain. The simulation calculations are in good agreement with experimental results. (authors)

Proportional counter with a uniform electric field in the zone of avalanche multiplication of electrons

International Nuclear Information System (INIS)

Marzec, J.; Pawlowski, Z.

1982-01-01

The work describes the construction of a proportional counter with a uniform electric field in the zone of avalanche multiplication of electrons. It has been shown that in this counter filled with Penning's mixtures Ne+Ar+CO 2 , Ne+CH 4 and Ar+C 2 H 2 , much higher resolutions are obtained than in typical cylindrical counters. In the counter described filled with a mixture of Ne+1%CH 4 , a resolution of fwhm=10.5% has been obtained for E=5.9 keV. (orig.)

Absolute calibration of TFTR helium proportional counters

International Nuclear Information System (INIS)

Strachan, J.D.; Diesso, M.; Jassby, D.; Johnson, L.; McCauley, S.; Munsat, T.; Roquemore, A.L.; Loughlin, M.

1995-06-01

The TFTR helium proportional counters are located in the central five (5) channels of the TFTR multichannel neutron collimator. These detectors were absolutely calibrated using a 14 MeV neutron generator positioned at the horizontal midplane of the TFTR vacuum vessel. The neutron generator position was scanned in centimeter steps to determine the collimator aperture width to 14 MeV neutrons and the absolute sensitivity of each channel. Neutron profiles were measured for TFTR plasmas with time resolution between 5 msec and 50 msec depending upon count rates. The He detectors were used to measure the burnup of 1 MeV tritons in deuterium plasmas, the transport of tritium in trace tritium experiments, and the residual tritium levels in plasmas following 50:50 DT experiments

Proportional counter with a uniform electric field in the zone of avalanche multiplication of electrons

Energy Technology Data Exchange (ETDEWEB)

Marzec, J.; Pawlowski, Z. (Politechnika Warszawska (Poland). Inst. Radioelektroniki)

1982-09-15

The work describes the construction of a proportional counter with a uniform electric field in the zone of avalanche multiplication of electrons. It has been shown that in this counter filled with Penning's mixtures Ne+Ar+CO/sub 2/, Ne+CH/sub 4/ and Ar+C/sub 2/H/sub 2/, much higher resolutions are obtained than in typical cylindrical counters. In the counter described filled with a mixture of Ne+1%CH/sub 4/, a resolution of fwhm=10.5% has been obtained for E=5.9 keV.

CWRU multiwire proportional counter readout system

International Nuclear Information System (INIS)

Bevington, P.R.; Leskovec, R.A.

1977-01-01

An electronic system is described which translates pulses from individual wires of multiwire proportional counters into binary addresses indicating the location of the wires in the chambers. The system combines a fast (<100 ns) serial scan of an event buffer with parallel encoding to provide fast transfer of addresses (250 ns per hit). The buffer has provision for disabling the input less than 40 ns after detection of an event to suppress recording of multiple hits caused by individual events. The encoder can digitize the address of every hit encountered or just the first addresses of contiguous hits. The system includes a coincidence trigger for determining whether timing criteria have been satisfied between chambers and with external devices. Events which do not meet the coincidence criteria are typically reset within 400 ns. The addresses are transferred to a computer interface through CAMAC modules. Multiple buffering permits further data acquisition during CAMAC transfer cycles. (Auth.)

Fabrication of preamplifier for proportional counter

International Nuclear Information System (INIS)

Lotfi, Y.; Yazdanpanah, M.; Talebi, B.; Mohammadi, A.; Etaati, Gh.

2002-01-01

We have tried to describe techniques of preamplifier fabrication for proportional counter. At first electronic circuit of preamplifier has been analyzed by means of Or cad 9.1. Then we assembled the circuit. Thereafter essential and standard parameters of preamplifier has been measured and compared with foreign made one, according to IEEE standard method. (IEEE Std 301-1988) Specification for our preamplifier is: 1. Rise time of output plus: 25 nsec. 2. Fall time of output pulse: 50μ sec. 3. Charge sensitive: 46.3 mV/pc. 4. Average noise: 500 ion pair (rms) 5. Count R ate L imit: 9.14*10 10 Count/sec. 6. Resolution: %1.3 7. Spectrum of Bf3 detector to 300μ Ci Am-Be source for this preamplifier is the same as foreign one. On the Whole comparison of this preamplifier with the foreign one shows that their parameters similarity is about %95

Set-up of proportional counter L2 for 14C measurements with improved precision

International Nuclear Information System (INIS)

Goslar, T.; Pazdur, A.; Pazdur, M.F.; Walanus, A.; Zastawny, A.

1990-01-01

Radiocarbon dating with improved precision denotes determination of conventional radiocarbon dates with accuracy equal to ca ± 25 yr. The paper presents some fundamental data concerning construction and design of the proportional counter L2, the results of calibration of the counter, including detailed information on changes of the background counting rate. The counter L2 enables dating of samples up to 50 000 yr. For samples younger than 3000 yr the error of dating is equal to ca ± 25 yr. 4 figs., 1 tab., 9 refs. (author)

Risetime discrimination applied to pressurized Xe gas proportional counter for hard x-ray detection

International Nuclear Information System (INIS)

Fujii, Masami; Doi, Kosei

1978-01-01

A high pressure Xe proportional counter has been developed for hard X-ray observation. This counter has better energy-resolving power than a NaI scintillation counter, and the realization of large area is relatively easy. This counter is constructed with a cylindrical aluminum tube, and this tube can be used at 40 atmospheric pressure. The detection efficiency curves were obtained in relation to gas pressure. It is necessary to reduce impurities in the Xe gas to increase the energy-resolving power of the counter. The increase of gas pressure made the resolving power worse. The characteristics of the counter were stable for at least a few months. The wave form discrimination was applied to reduce the background signals such as pulses caused by charged particles and gamma-ray. This method has been used for normal pressure counter, and in the present study, it was applied for the high pressure counter. It was found that the discrimination method was able to be applied to this case. (Kato, T.)

Determination of optimum shape and dimensions of anode high-voltage isolators for gaseous proportional counters

International Nuclear Information System (INIS)

Jelen, K.; Jagusztyn, W.

1975-01-01

The influence of the shape and dimensions of the high-voltage anode-to-cathods isolator on the regularity of the electrostatic field distribution along the anode of a cylindrical gaseous proportional counter is studied. For a counter of fixed dimensions, the length and diameter of the glass isolators were optimized to disrupt as little as possible the regularity of the field distribution in the active volume of the counter. Results of calculations are in agreement with experimental data. The obtained results provide a basis for obtaining a correct ratio of the active volume of the counter to its total volume. (author)

Low-pressure, multistep, multiwire proportional counter for the time-of-flight isochronous spectrometer

International Nuclear Information System (INIS)

Vieira, D.J.

1985-01-01

A low-pressure, multistep, multiwire proportional counter (MSMWPC) has been developed for the characterization and testing of the time-of-flight isochronous (TOFI) spectrometer and its associated secondary-beam transport line. This type of counter was selected because of its high sensitivity, large dynamic range, and good position (0.2 mm FWHM) and timing (180 ps FWHM) resolution. Furthermore, because the counter operates at low gas pressures (1-10 torr) and high electric-field strengths, which enable short collection times, it can be used as a transmission counter with thin gas-isolation windows and it can operate at high counting rates. Here the authors discuss the basic operating principle of the MSMWPC, describe the technical details of the detector and signal processing, and report on the performance they have measured for alpha particles and fission fragments

A multiwire proportional counter for very high counting rates

International Nuclear Information System (INIS)

Barbosa, A.F.; Guedes, G.P.; Tamura, E.; Pepe, I.M.; Oliveira, N.B.

1997-12-01

Preliminary measurements in a proportional counter with two independently counting wires showed that counting rates up to 10 6 counts/s per wire can be reached without critical loss in the true versus measured linearity relation. Results obtained with a detector containing 30 active wires (2 mm pitch) are presented. To each wire is associated a fast pre-amplifier and a discriminator channel. Global counting rates in excess to 10 7 events/s are reported. Data acquisition systems are described for 1D (real time) and 2D (off-line) position sensitive detection systems. (author)

A pill-box design, flow type, gas scintillation proportional counter

International Nuclear Information System (INIS)

Garg, S.P.; Sharma, R.C.; Bhati, S.; Somasundaram, S.

1982-01-01

A gas scintillation proportional counter of 'pill-box' design operated with argon + 2.5% nitrogen gas in continuous flow, has been developed. An energy resolution of 1.6% is obtained for 239 Pu α-particles emitted from a mixed nuclide source of 239 Pu- 241 Am- 244 Cm and injected into the counter parallel to the anode. The risetime of the scintillation pulse is found to be less than 0.5 μs. Measurements have been made of charge and light gain factors as a function of anode voltage. It is found that for a given anode voltage, the scintillation pulse amplitude increases sharply with the addition of nitrogen to argon and reaches a maximum at about 2.5% and then decreases slowly, whereas the charge pulse amplitude reduces monotonically. Nitrogen improvement factors with the addition of 2.5% nitrogen to argon are found to be different for two photomultipliers with different photocathode responses. The improvement in energy resolution as a result of addition of nitrogen to argon is discussed. Comments are made on the intrinsic energy resolution capabilities of such a counter. (orig.)

The suppression of destructive sparks in parallel plate proportional counters

Energy Technology Data Exchange (ETDEWEB)

Cockshott, R.A.; Mason, I.M.

1984-02-01

The authors find that high energy background events produce localised sparks in parallel plate counters when operated in the proportional mode. These sparks increase dead-time and lead to degradation ranging from electrode damage to spurious pulsing and continuous breakdown. The problem is particularly serious in low energy photon detectors for X-ray astronomy which are required to have lifetimes of several years in the high radiation environment of space. For the parallel plate imaging detector developed for the European X-ray Observatory Satellite (EXOSAT) they investigate quantitatively the spark thresholds, spark rates and degradation processes. They discuss the spark mechanism, pointing out differences from the situation in spark chambers and counters. They show that the time profile of the sparks allows them to devise a spark suppression system which reduces the degradation rate by a factor of ''200.

Response matrix of a multisphere neutron spectrometer with an 3 He proportional counter

International Nuclear Information System (INIS)

Vega C, H.R.; Manzanares A, E.; Hernandez D, V.M.; Mercado S, G.A.

2005-01-01

The response matrix of a Bonner sphere spectrometer was calculated by use of the MCNP code. As thermal neutron counter, the spectrometer has a 3.2 cm-diameter 3 He-filled proportional counter which is located at the center of a set of polyethylene spheres. The response was calculated for 0, 3, 5, 6, 8, 10, 12, and 16 inches-diameter polyethylene spheres for neutrons whose energy goes from 10 -9 to 20 MeV. The response matrix was compared with a set of responses measured with several monoenergetic neutron sources. In this comparison the calculated matrix agrees with the experimental results. The matrix was also compared with the response matrix calculated for the PTB C spectrometer. Even though that calculation was carried out using a detailed model to describe the proportional counter; both matrices do agree, but small differences are observed in the bare case because of the difference in the model used during calculations. Other differences are in some spheres for 14.8 and 20 MeV neutrons, probably due to the differences in the cross sections used during both calculations. (Author) 28 refs., 1 tab., 6 figs

The miniaturized proportional counter HD-2(Fe)/(Si) for the GALLEX solar neutrino experiment

Energy Technology Data Exchange (ETDEWEB)

Wink, R.; Anselmann, P.; Doerflinger, D.; Hampel, W.; Heusser, G.; Kirsten, T.; Moegel, P.; Pernicka, E.; Plaga, R.; Schlosser, C. (Max Planck Inst. fuer Kernphysik, Heidelberg (Germany))

1993-06-01

The miniaturized proportional counters used for the detection of [sup 71]Ge in the solar neutrino project GALLEX are characterized. We also report on the construction techniques applied to build these counters and to achieve the described performance. A very low counting background is achieved by, among other things, careful selection of the materials used for construction. The total [sup 71]Ge detection efficiency after applying cuts to reduce the background is about 66%. (orig.).

Calibration methodology for proportional counters applied to yield measurements of a neutron burst

International Nuclear Information System (INIS)

Tarifeño-Saldivia, Ariel; Pavez, Cristian; Soto, Leopoldo; Mayer, Roberto E

2015-01-01

This work introduces a methodology for the yield measurement of a neutron burst using neutron proportional counters. The methodology is based on the calibration of the counter in pulse mode, and the use of a statistical model to estimate the number of detected events from the accumulated charge resulting from detection of the burst of neutrons. An improvement of more than one order of magnitude in the accuracy of a paraffin wax moderated 3 He-filled tube is obtained by using this methodology with respect to previous calibration methods. (paper)

A versatile gas-flow proportional counter for Moessbauer spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Bibicu, I., E-mail: bibicu@infim.ro [National Institute for Materials Physics (Romania); Nicolescu, G. [IFIN-HH, National Institute of Physics and Nuclear Engineering (Romania); Cretu, C. [Transylvania University, Physics Department (Romania)

2009-07-15

This article presents a versatile gas-flow proportional counter for surface and transmission Moessbauer spectroscopy, suitable for studies with {sup 57}Fe, {sup 119}Sn and {sup 151}Eu isotopes. The main advantages obtained by new design are: (1) the height of the detection volume can be changed in large limits from 0 to 38 mm, (2) the detection volume can be choose symmetrical or not in respect with anode plan, (3) the anode replacement is easily (4) and different anode configuration can be used. The characteristics of the detector, operating at room temperature, are reported.

A multiwire proportional counter for very high counting rates

Energy Technology Data Exchange (ETDEWEB)

Barbosa, A F; Guedes, G P [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil); Tamura, E [Laboratorio Nacional de Luz Sincrotron (LNLS), Campinas, SP (Brazil); Pepe, I M; Oliveira, N B [Bahia Univ., Salvador, BA (Brazil). Inst. de Fisica

1997-12-01

Preliminary measurements in a proportional counter with two independently counting wires showed that counting rates up to 10{sup 6} counts/s per wire can be reached without critical loss in the true versus measured linearity relation. Results obtained with a detector containing 30 active wires (2 mm pitch) are presented. To each wire is associated a fast pre-amplifier and a discriminator channel. Global counting rates in excess to 10{sup 7} events/s are reported. Data acquisition systems are described for 1D (real time) and 2D (off-line) position sensitive detection systems. (author) 13 refs., 6 figs.

Quality measurement by proportional counter with B

International Nuclear Information System (INIS)

Onizuka, Yoshihiko; Endo, Satoru; Tanaka, Kenichi

2005-01-01

The dosimetry of air and the tissue-equivalent phantom made of acryl are carried out by the tissue-equivalent proportional counter (TEPC) and TEPC with wall contained B, and both results were compared. The changes of quality with distance from the beam center are determined by the frequency mean renewal energy y F (y)and the dose mean renewal energy y D (y) as indicators of quality. Both y F (y)and y D (y) of tissue-equivalent phantom are larger than air, but very large change was not observed in all distance. The dose rate is determined by y D (y), the number of events and measurement time. Change of dose rate was larger than the change of quality. The maximum value of dose rate depended on γray and neutron beam showed at the point 2 cm away from the center. (S.Y.)

A helium-3 proportional counter technique for estimating fast and intermediate neutrons

International Nuclear Information System (INIS)

Kosako, Toshiso; Nakazawa, Masaharu; Sekiguchi, Akira; Wakabayashi, Hiroaki.

1976-11-01

3 He proportional counter was employed to determine the fast and intermediate neutron spectra of wide energy region. The mixed gas ( 3 He, Kr) type counter response and the spectrum unfolding code were prepared and applied to some neutron fields. The counter response calculation was performed by using the Monte Carlo code, paying regards to dealing of the particle range calculation of the mixed gas. An experiment was carried out by using the van de Graaff accelerator to check the response function. The spectrum unfolding code was prepared so that it may have the function of automatic evaluation of the higher energy spectrum's effect to the pulse hight distribution of the lower energy region. The neutron spectra of the various neutron fields were measured and compared with the calculations such as the discrete ordinate Sn calculations. It became clear that the technique developed here can be applied to the practical use in the neutron energy range from about 150 KeV to 5 MeV. (auth.)

Interfacing a gas proportional counter with a mass spectrometer: Simultaneous display of GC/MS and radiocarbon data

International Nuclear Information System (INIS)

Peterson, G.S.; Laemmerhirt, D.F.; Weaver, A.

1985-01-01

To facilitate the location of pesticides and monitor their metabolism in environmental and biological systems, carbon-14 labelling of the parent compound is used. Detection of the radiolabel is achieved using a gas proportional counter, while identification of the labelled components is most easily accomplished with mass spectrometry. However, when these two operations are performed separately, correlation of the information is awkward, at best. Since each is a destructive detector, simultaneous monitoring of the outposts requires an effluent splitter. The complete system consists of a variable splitter, which allows control of the ratio of the GC effluent to the two instruments, and signal processing circuitry for simultaneous recording and storage of radiocarbon and mass spectral data. Modifications to a Finnigan GC/MS and Gas Proportional Counter included a high temperature GC effluent splitter with glass-lined connecting tubing, and a data interface, including analog to digital and serial to parallel conversions with optical isolation between the gas proportional counter and the computer. The splitter restricted the flow to the mass spectrometer, preventing flow completely in the closed position. The split was adjusted to maximize flow to the mass spectrometer using the vacuum as a rough guide (1.0 x 10 -5 torr in EI, 7.5 x 10 -5 torr in CI). A heated transfer line between the transfer oven and gas proportional counter prevented condensation of eluting components prior to radiocarbon detection

A comparison between the measurements of Kr-85 in environmental samples by liquid scintillation and proportional counters

International Nuclear Information System (INIS)

Heras Iniquez, M.C.; Perez Garcia, M.M.

1983-01-01

The most used methods for the measurement of Kr-81 beta-activity after their concentration and aisolation are the liquid scintillation counting and the proportional counter. In this work the beta activity of concentrated and aisolated Kr-85 samples measured in collaboration with the Max-Planck Institut fur Kernphyslk, Aussenstelle Freiburg. Samples taken both In Madrid and Frelburg are measured by proportional counters in the Max-Planck lnstitut, Freibury and by liquid scintillation counting in JEN, Madrid. The comparison of both measurements do not show appreciable discrepancy between the results obtained to both techniques. (Author)

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

Energy Technology Data Exchange (ETDEWEB)

Konijn, J; Lauber, A; Tollander, B

1963-08-15

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

Comprehensive applications of the gas flow proportional counters for radiological surveillance

International Nuclear Information System (INIS)

Babu, D.A.R.; Raman, Anand; Ashokkumar, P.; Sharma, D.N.

2008-01-01

Gas Flow Proportional Counters (GFPC) have been developed indigenously for various radiation protection applications. These detectors can be fabricated for 2 inches diameter filter paper sample counting applications to large area (∼1500 cm 2 ) detectors for surface contamination applications. Thin entrance windows allow non penetrating type of radiations like alpha and low energy beta particles, Efficiencies (for alpha and beta radiations) are comparable to conventional detectors used to measure these radiations. Poor gamma efficiency ( 2 /γ ratio, a high figure of merit and enables efficient gamma background rejection. These detectors are quite suitable for Indian environmental conditions. Three systems have been developed and successfully incorporated in to the radiation surveillance program at various nuclear facilities. The systems based on GFPC detectors include: a) Multiple sample gross alpha counting system; b) Laundry monitoring system; c) Alpha hand contamination monitoring system. The first of these enables simultaneous gross alpha counting of five air activity filter paper samples. The area of the detector surface is optimized to cover the 2 inches sized filter paper samples routinely used for the purpose. Five numbers of GFPC 's are arranged sequentially coupled to five individual amplifiers - micro controller modules to process the signal from the five counters. The laundry monitor which is micro controller based system consists of four large area multiwire GFPC detectors (700 cm 2 sensitive area) used to monitor alpha contamination of decontaminated laundry, Each detector uses a charge sensitive preamplifier coupled to I 2 C counter. The alpha hand monitoring system consists of four large area multiwire gas flow proportional detectors (330 cm 2 sensitive area each). A micro controller-based module is employed to initiate the counting process automatically when the hands are inserted in to the suitably designed window slots and provides audio and

Direct measurement of gaseous activities by diffusion-in long proportional counter method

International Nuclear Information System (INIS)

Yoshida, M.; Yamamoto, T.; Wu, Y.; Aratani, T.; Uritani, A.; Mori, C.

1993-01-01

Direct measurement of gaseous activities by the diffusion-in long proportional counter method (DLPC method) was studied. The measuring time without end effect was estimated by observing the behavior of 37 Ar in the counter and was long enough to carry out the accurate activity measurement. The correction for wall effect was also examined on the basis of the measured and calculated correction factors. Among the tested gases of methane, P10 gas and propane, P10 gas was made clear to be a suitable counting gas for the DLPC method because of good diffusion properties and small wall effect. This method is quite effective for standardization of gaseous activities used for tracer experiments and calibration works of radioactive gas monitoring instruments. (orig.)

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%

Numerical modelling of tissue-equivalent proportional counters

International Nuclear Information System (INIS)

Segur, P.; Colautti, P.

1995-01-01

In this paper a survey is given of the various numerical techniques employed to study the transport of ionising particles inside a TEPC. The first part is devoted to the description of the general concept of particle transport calculations. Thereafter, the different methods available to study transport phenomena and energy deposition in the sensitive volume and in counter walls are described. Finally, the basic ionisation mechanisms which may occur in a counter are described, and the non-equilibrium phenomena which play an important role mainly for counters that are to be used in measurements at the nanodosemeter level are studied. (author)

Development of new type boron-coating proportional counter and its experimental investigation and simulation calculation

International Nuclear Information System (INIS)

Zhang Zixia; Wei Zhiyong; Fang Meihua; Qiang Peng; Zhu Li; Chen Guoyun

2015-01-01

Three materials wherein suitable proportion of isotope enriched 10 B powder, 1, 2-ethylene dichloride and formvar resin were blended to make 10 B neutron sensitive coating by oneself. A new type proportional counter that coated with 10 B neutron sensitive coating was made. Furthermore, in order to increase the character and quality of the neutron detector, a set of 14 annulus epoxy sheets which were sided with 10 B film were placed in the tube. A series performance tests were done by 241 Am-Be neutron source. The tests of 3.7 × 10 9 Bq 211 Am-Be neutron source show that the plateau length of detector is 150 V from 750 V to 900 V, while the plateau slope is 8.2%/100 V. When the working voltage is 800 V, the count rate of new type boron-coating proportional counter is 50 s -1 . The level of sensitivity is 0.71 cm 2 . Compared with the detector only coated with 10 B film in the inner walls of detector, neutron sensitivity area of the new detector increases to 3.15 times. The results show that the plateau length increases from 80 V to 150 V, and the plateau slope is improved from 12.4%/100 V to 7.58%/100 V, while the neutron sensitivity increases to 2.63 times. Using Geant4 software based on Monte Carlo method, this paper presented the response and detection efficiency of new type boron-coating proportional counter, which was covered with φ55 mm × 250 mm cylinder high density polyethylene moderator material. The simulation results of Geant4 are in agreement with the results of 241 Am-Be neutron source experiment. It shows the reliability of simulation application. (authors)

Demand-type gas supply system for rocket borne thin-window proportional counters

Science.gov (United States)

Acton, L. W.; Caravalho, R.; Catura, R. C.; Joki, E. G.

1977-01-01

A simple closed loop control system has been developed to maintain the gas pressure in thin-window proportional counters during rocket flights. This system permits convenient external control of detector pressure and system flushing rate. The control system is activated at launch with the sealing of a reference volume at the existing system pressure. Inflight control to plus or minus 2 torr at a working pressure of 760 torr has been achieved on six rocket flights.

{sup 10}B multi-grid proportional gas counters for large area thermal neutron detectors

Energy Technology Data Exchange (ETDEWEB)

Andersen, K. [ESS, P.O. Box 176, SE-221 00 Lund (Sweden); Bigault, T. [ILL, BP 156, 6, rue Jules Horowitz, 38042 Grenoble Cedex 9 (France); Birch, J. [Linköping University, SE-581, 83 Linköping (Sweden); Buffet, J. C.; Correa, J. [ILL, BP 156, 6, rue Jules Horowitz, 38042 Grenoble Cedex 9 (France); Hall-Wilton, R. [ESS, P.O. Box 176, SE-221 00 Lund (Sweden); Hultman, L. [Linköping University, SE-581, 83 Linköping (Sweden); Höglund, C. [ESS, P.O. Box 176, SE-221 00 Lund (Sweden); Linköping University, SE-581, 83 Linköping (Sweden); Guérard, B., E-mail: guerard@ill.fr [ILL, BP 156, 6, rue Jules Horowitz, 38042 Grenoble Cedex 9 (France); Jensen, J. [Linköping University, SE-581, 83 Linköping (Sweden); Khaplanov, A. [ILL, BP 156, 6, rue Jules Horowitz, 38042 Grenoble Cedex 9 (France); ESS, P.O. Box 176, SE-221 00 Lund (Sweden); Kirstein, O. [Linköping University, SE-581, 83 Linköping (Sweden); Piscitelli, F.; Van Esch, P. [ILL, BP 156, 6, rue Jules Horowitz, 38042 Grenoble Cedex 9 (France); Vettier, C. [ESS, P.O. Box 176, SE-221 00 Lund (Sweden)

2013-08-21

{sup 3}He was a popular material in neutrons detectors until its availability dropped drastically in 2008. The development of techniques based on alternative convertors is now of high priority for neutron research institutes. Thin films of {sup 10}B or {sup 10}B{sub 4}C have been used in gas proportional counters to detect neutrons, but until now, only for small or medium sensitive area. We present here the multi-grid design, introduced at the ILL and developed in collaboration with ESS for LAN (large area neutron) detectors. Typically thirty {sup 10}B{sub 4}C films of 1 μm thickness are used to convert neutrons into ionizing particles which are subsequently detected in a proportional gas counter. The principle and the fabrication of the multi-grid are described and some preliminary results obtained with a prototype of 200 cm×8 cm are reported; a detection efficiency of 48% has been measured at 2.5 Å with a monochromatic neutron beam line, showing the good potential of this new technique.

Calibration of an ultra-low-background proportional counter for measuring 37Ar

International Nuclear Information System (INIS)

Seifert, A.; Aalseth, C. E.; Bonicalzi, R. M.; Bowyer, T. W.; Day, A. R.; Fuller, E. S.; Haas, D. A.; Hayes, J. C.; Hoppe, E. W.; Humble, P. H.; Keillor, M. E.; LaFerriere, B. D.; Mace, E. K.; McIntyre, J. I.; Merriman, J. H.; Miley, H. S.; Myers, A. W.; Orrell, J. L.; Overman, C. T.; Panisko, M. E.

2013-01-01

An ultra-low-background proportional counter design has been developed at Pacific Northwest National Laboratory (PNNL) using clean materials, primarily electro-chemically-purified copper. This detector, along with an ultra-low-background counting system (ULBCS), was developed to complement a new shallow underground laboratory (30 meters water-equivalent) at PNNL. The ULBCS design includes passive neutron and gamma shielding, along with an active cosmic-veto system. This system provides a capability for making ultra-sensitive measurements to support applications like age-dating soil hydrocarbons with 14 C/ 3 H, age-dating of groundwater with 39 Ar, and soil-gas assay for 37 Ar to support On-Site Inspection (OSI). On-Site Inspection is a key component of the verification regime for the Comprehensive Nuclear-Test-Ban Treaty (CTBT). Measurements of radionuclides created by an underground nuclear explosion are valuable signatures of a Treaty violation. For OSI, the 35-day half-life of 37 Ar, produced from neutron interactions with calcium in soil, provides both high specific activity and sufficient time for inspection before decay limits sensitivity. This work describes the calibration techniques and analysis methods developed to enable quantitative measurements of 37 Ar samples over a broad range of proportional counter operating pressures. These efforts, along with parallel work in progress on gas chemistry separation, are expected to provide a significant new capability for 37 Ar soil gas background studies

Particle unstable excited states in /sup 9/Be influence of beta recoil and width on delayed particle spectra

CERN Document Server

Nyman, G H; Jonson, B; Kratz, K L; Larsson, P O; Mattsson, S; Ziegert, W

1981-01-01

The light nucleus /sup 9/Be has been studied through the emission of beta-delayed neutrons and alpha particles from /sup 9/Li. The activity is produced at the ISOLDE facility in fragmentation reactions induced either by 600 MeV proton or 910 MeV /sup 3/He beams from the CERN Synchro-cyclotron. After mass separation neutron spectra are recorded using /sup 3/He-filled proportional counters, while surface barrier detectors are used for the spectroscopy of alpha particles. Effects on the spectrum shape induced by recoil and polarization phenomena as well as large widths of the intermediate states are discussed. (14 refs).

Use of the helium-3 proportional counter for neutron spectrometry

International Nuclear Information System (INIS)

Vialettes, H.; Le Thanh, P.

1967-01-01

Up to now, two methods have been mainly used for neutron spectrometry near nuclear installations: - photographic emulsion spectrometry - the so-called, 'multisphere' technique spectrometry. The first method, which is fairly difficult to apply, has a threshold energy of about 500 keV; this is a big disadvantage for an apparatus which has to be used for spectrometry around nuclear installations where the neutron radiation is very much degraded energetically. The second method does not suffer from this disadvantage but the results which it yields are only approximate. In order to extend the energy range of the neutron spectra studied with sufficient accuracy the use of a helium-3 proportional counter has been considered. This report presents the principles of operation of the helium-3 spectrometer, and the calculation methods which make it possible to take into account the two main effects tending to deform the spectra obtained: - energy absorption by the walls of the counter, - energy loss of the incident neutrons due to elastic collisions with helium-3 nuclei. As an example of the application, the shape of the neutron spectrum emitted by a polonium-lithium source is given; the results obtained are in excellent agreement with theoretical predictions. (authors) [fr

Output pulse-shapes of position-sensitive proportional counters using high resistance single wire

International Nuclear Information System (INIS)

Iwatani, Kazuo; Nishiyama, Fumitaka; Hasai, Hiromi

1980-01-01

The measurements and model analysis of the output pulse-shapes from a single wire proportional counter (SWPC) which has a high resistance anode are described. The characteristics of the observed pulse-shapes are determined by only one parameter which is a function of anode resistance and load resistance and they are reproduced by a simple model. Using this model, the methods for position read-out are discussed in a systematical way. (author)

The n,{gamma} discrimination in recoil-proton proportional counters. Application to the measurement of fast neutron spectra; Discrimination n,{gamma} dans les compteurs proportionnels a protons de recul. Application a la mesure des spectres de neutrons rapides

Energy Technology Data Exchange (ETDEWEB)

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

1969-07-01

A description is given of a spectrometry chain working in the energy range of a few keV to 1 MeV, and designed for measurement of fast neutron spectra. It consists of detectors, recoil proton proportional counters built especially for this work by R. COMTE (DEG/SER) and which make it possible to cover the energy range and also associated electronic equipment. A brief description is first given of the physical processes involved: (n,p) collisions in the gas, influence of {gamma} radiation; the method of discrimination is then presented. It is based on the difference in the rise-times of the pulses. In the experiments described here the use of a bi-parametric system made it possible to employ the most simple discrimination device, based on the fact that the high frequency gamma pulse components are, at a given energy, weaker than those of the neutron pulses. Results are given of measurements carried out on the Van der Graaff (mono-energetic neutrons for testing the linearity of the chain and the resolving power of the counters), and of those made in a sub-critical system Hug at Cadarache. (author) [French] On decrit une chaine de spectrometrie travaillant dans le domaine d'energie de quelques keV a 1 MeV destinee a la mesure des spectres de neutrons rapides. Elle comprend les detecteurs, compteurs proportionnels a protons de recul, realises specialement pour cette etude par M. R. COMTE (DEG/SER), permettant de couvrir la gamme d'energie et l'electronique associee. Apres un rappel des processus physiques mis en jeu: chocs (n,p) dans les gaz, influence des rayonnements {gamma}, on expose la methode de discrimination utilisee. Celle-ci est basee sur la difference des temps de montee des impulsions. Au cours des experiences rapportees ici, la mise en oeuvre d'un ensemble bi-parametrique a permis d'utiliser le dispositif de discrimination le plus simple, base sur la remarque que les composantes a haute frequence des impulsions {gamma} sont, a energie egale, plus faibles

The n,{gamma} discrimination in recoil-proton proportional counters. Application to the measurement of fast neutron spectra; Discrimination n,{gamma} dans les compteurs proportionnels a protons de recul. Application a la mesure des spectres de neutrons rapides

Energy Technology Data Exchange (ETDEWEB)

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

1969-07-01

A description is given of a spectrometry chain working in the energy range of a few keV to 1 MeV, and designed for measurement of fast neutron spectra. It consists of detectors, recoil proton proportional counters built especially for this work by R. COMTE (DEG/SER) and which make it possible to cover the energy range and also associated electronic equipment. A brief description is first given of the physical processes involved: (n,p) collisions in the gas, influence of {gamma} radiation; the method of discrimination is then presented. It is based on the difference in the rise-times of the pulses. In the experiments described here the use of a bi-parametric system made it possible to employ the most simple discrimination device, based on the fact that the high frequency gamma pulse components are, at a given energy, weaker than those of the neutron pulses. Results are given of measurements carried out on the Van der Graaff (mono-energetic neutrons for testing the linearity of the chain and the resolving power of the counters), and of those made in a sub-critical system Hug at Cadarache. (author) [French] On decrit une chaine de spectrometrie travaillant dans le domaine d'energie de quelques keV a 1 MeV destinee a la mesure des spectres de neutrons rapides. Elle comprend les detecteurs, compteurs proportionnels a protons de recul, realises specialement pour cette etude par M. R. COMTE (DEG/SER), permettant de couvrir la gamme d'energie et l'electronique associee. Apres un rappel des processus physiques mis en jeu: chocs (n,p) dans les gaz, influence des rayonnements {gamma}, on expose la methode de discrimination utilisee. Celle-ci est basee sur la difference des temps de montee des impulsions. Au cours des experiences rapportees ici, la mise en oeuvre d'un ensemble bi-parametrique a permis d'utiliser le dispositif de discrimination le plus simple, base sur la remarque que les composantes a haute frequence des impulsions {gamma} sont, a

The Rutherford Appleton Laboratory's Mark I Multiwire Proportional Counter positron camera

International Nuclear Information System (INIS)

Bateman, J.E.; Connolly, J.F.; Stephenson, R.; Tappern, G.J.; Flesher, A.C.

1983-01-01

A small model of a proposed large aperture positron camera has been developed at Rutherford Appleton Laboratory. Based on Multiwire Proportional Counter technology it uses lead foil cathodes which function simultaneously as converters for the 511 keV gamma rays and readout electrodes for a delay line readout system. The detectors have been built up into a portable imaging system complete with a dedicated computer for data taking, processing and display. A complete hardware system and sufficient software was provided to permit hospital based colleagues to generate useful images easily. A complete description of the system is given with performance figures and some of the images obtained are presented. (author)

Annular shape silver lined proportional counter for on-line pulsed neutron yield measurement

International Nuclear Information System (INIS)

Dighe, P.M.; Das, D.

2015-01-01

An annular shape silver lined proportional counter is developed to measure pulsed neutron radiation. The detector has 314 mm overall length and 235 mm overall diameter. The central cavity of 150 mm diameter and 200 mm length is used for placing the neutron source. Because of annular shape the detector covers >3π solid angle of the source. The detector has all welded construction. The detector is developed in two halves for easy mounting and demounting. Each half is an independent detector. Both the halves together give single neutron pulse calibration constant of 4.5×10 4 neutrons/shot count. The detector operates in proportional mode which gives enhanced working conditions in terms of dead time and operating range compared to Geiger Muller based neutron detectors

Investigations of X-ray response of single wire anode Ar-N2 flow type gas scintillation proportional counters

International Nuclear Information System (INIS)

Garg, S.P.; Sharma, R.C.

1984-01-01

The X-ray response of single wire anode gas scintillation proportional counters of two different geometries operated with argon+nitrogen gases in continuous flow has been investigated with wire anodes of diameters 25 μm to 1.7 mm. An energy resolution of 19% is obtained for 5.9 keV X-rays entering the counter perpendicular to the anode in pill-box geometry with 25 μm diameter anode. With cylindrical geometry counters energy obtained at 5.9 keV are 18%, 24% and 33% for 50 μm, 0.5 mm and 1.7 mm diameter anodes respectively. An analysis of the observed resolution shows that the contribution from photon counting statistics to the relative variance of scintillation pulses even for X-rays in Ar-N 2 single wire anode gas scintillation proportional counters is small and is not a limiting factor. The energy resolution with thicker anodes, where the contribution from the variance of the charge multiplication factor also has been minimised, is found to deteriorate mainly by the interaction in the scintillation production region. Comments are made on the possibility of improvement in energy resolution by suppression of pulses due to such interactions with the help of the pulse risetime discrimination technique. (orig.)

Electronic system for recording proportional counter rare pulses with the pulse shape analysis

International Nuclear Information System (INIS)

Barabanov, I.R.; Gavrin, V.N.; Zakharov, Yu.I.; Tikhonov, A.A.

1984-01-01

The anutomated system for recording proportional counter rare pulses is described. The proportional counters are aimed at identification of 37 Ar and H7 1 Gr decays in chemical radiation detectors of solar neutrino. Pulse shape recording by means of a storage oscilloscope and a TV display is performed in the system considered besides two-parametric selection of events (measurement of pulse amplitude in a slow channel and the amplitude of pulse differentiated with time constant of about 10 ns in a parallel fast channel). Pulse discrimination by a front rise rate provides background decrease in the 55 Fe range (5.9 keV) by 6 times; the visual analysis of pulse shapes recorded allows to decrease the background additionally by 25-30%. The background counting rate in the 55 Fe range being equal to 1 pulse per 1.5 days, is obtained when using the installation described above, as well as the passive Pb shield 5 cm thick, and the active shield based on the anticoincidence NaI(Tl) detector with the cathode 5.6 mm in-diameter made of Fe fabircated by zone melting. The installation described allows to reach the background level of 0.6 pulse/day (the total coefficient of background attenuation is 400). Further background decrease is supposed to be provided by installation allocation in the low-noise underground laboratory of the Baksan Neutrino Observatory

Determination of dose equivalent with tissue-equivalent proportional counters

International Nuclear Information System (INIS)

Dietze, G.; Schuhmacher, H.; Menzel, H.G.

1989-01-01

Low pressure tissue-equivalent proportional counters (TEPC) are instruments based on the cavity chamber principle and provide spectral information on the energy loss of single charged particles crossing the cavity. Hence such detectors measure absorbed dose or kerma and are able to provide estimates on radiation quality. During recent years TEPC based instruments have been developed for radiation protection applications in photon and neutron fields. This was mainly based on the expectation that the energy dependence of their dose equivalent response is smaller than that of other instruments in use. Recently, such instruments have been investigated by intercomparison measurements in various neutron and photon fields. Although their principles of measurements are more closely related to the definition of dose equivalent quantities than those of other existing dosemeters, there are distinct differences and limitations with respect to the irradiation geometry and the determination of the quality factor. The application of such instruments for measuring ambient dose equivalent is discussed. (author)

Design and construction techniques for one-meter position sensitive proportional counters of the helical delay line type

International Nuclear Information System (INIS)

Orbesen, S.D.; Sherman, J.D.; Flynn, E.R.

1976-03-01

A description is given of the techniques involved in the construction of a one-meter long helical proportional counter which produces excellent position accuracy of 1 mm while yielding particle identification through a measurement of energy loss and total energy

Imaging micro-well proportional counters fabricated with masked UV laser ablation

CERN Document Server

Deines-Jones, P; Crawford, H; Hunter, S D

2002-01-01

The micro-well detector is a gas-proportional counter similar to the CAT (Bartol et al., J. Phys. III 6 (1996) 337) and WELL detectors (Bellazzini et al., Nucl. Instr. and Meth. A 423 (1999) 125). The micro-well is a cylindrical hole formed in the polymer substrate of commercially fabricated copper-clad flexible printed circuit board by UV laser ablation. The micro-wells are drilled at GSFC's UV laser-ablation facility. The cathode is a metal annulus that surrounds the opening of the well. The anode is a metal pad that fills the bottom of the well. Advantages of this topology include intrinsic two-dimensional sensing, thick robust electrodes, and large localized image charge on the cathodes. We have fabricated 5 cmx5 cm micro-well detectors with segmented anodes (1-d) and with both anodes and cathodes segmented (2-d), and have demonstrated: - stable, proportional operation at gas gains in excess of 30,000 in Ar- and Xe-based gases; - FWHM energy resolution of 20% at 6 keV in P-10; - preliminary 1-d spatial re...

Gas-multiplication factor of a proportional counter operated at low temperature described with the Diethorn, Rose-Korff and townsend expressions

Energy Technology Data Exchange (ETDEWEB)

Fukumura, Kazuko; Nakanishi, Akio; Kobayashi, Takayuki [Shiga Univ. of Medical Science, Otsu (Japan)

1996-07-01

In the present work, the gas-multiplication factor is expressed with the Rose-Korff and Townsend methods as well as with the Diethorn method. A proportional counter with helium or neon works only at low temperature. This is discussed in terms of the number of electrons emitted when an ion is neutralized at the cathode of the counter. (J.P.N.)

A technique for searching for the 2 K capture in 124Xe with a copper proportional counter

Science.gov (United States)

Gavrilyuk, Yu. M.; Gangapshev, A. M.; Kazalov, V. V.; Kuzminov, V. V.; Panasenko, S. I.; Ratkevich, S. S.; Tekueva, D. A.; Yakimenko, S. P.

2015-12-01

An experimental technique for searching for the 2 K capture in 124Xe with a large low-background copper proportional counter is described. Such an experiment is conducted at the Baksan Neutrino Observatory of the Institute for Nuclear Research of the Russian Academy of Sciences. The experimental setup is located in the Low-Background Deep-Level Laboratory at a depth of 4900 m.w.e., where the flux of muons of cosmic rays is suppressed by a factor of 107 relative to that at the Earth's surface. The setup incorporates a proportional counter and low-background shielding (18 cm of copper, 15 cm of lead, and 8 cm of borated polyethylene). The results of processing the data obtained in 5 months of live measurement time are presented. A new limit on the half-life of 124Xe with respect to the 2 K capture is set at the level of 2.5 × 1021 years.

Multi-level modelling of the response of the ultraminiature proportional counter: gas gain phenomena and pulse height spectra

International Nuclear Information System (INIS)

Olko, P.; Moutarde, C.; Segur, P.

1995-01-01

The ultraminiature proportional counters, UMC, unique radiation detectors for monitoring high intensity therapy fields, designed by Kliauga and operated at Columbia University (USA), have yielded a number of pulse height distributions for photons, neutrons and ions at simulated diameters of 5-50 nm. Monte Carlo calculations of the gas gain in such a counter questioned the possibility of achieving proportionally at such low simulated diameters. The response of the UMC has now been modelled taking into account both fluctuations of energy deposited in the counter volume and its calculated gas gain. Energy deposition was calculated using the MOCA-14, MOCA-8 and TRION codes, whereby distributions of ionisations d(j) after irradiations with 137 Cs, 15 MeV neutrons and 7 MeV.amu -1 deuterons were obtained. Monte Carlo calculations of electron avalanches in UMC show that the size of the single-electron avalanche P(n) reaching the anode depends strongly on the location of the primary ionisation within the counter volume. Distributions of the size of electron avalanches for higher numbers of primary ionisations, P *j (n), were obtained by successive convolutions of P(n). Finally, the counter response was obtained by weighting P *j (n) over d(j) distributions. On comparing the measured and calculated spectra it was concluded that the previously proposed single-electron peak calibration method might not be valid for the UMC due to the excessive width and overlap of electron avalanche distributions. Better agreement between the measured and calculated spectra is found if broader electron avalanche distributions than those used in the present calculations, are assumed. (author)

Use of the small gas proportional counters for the carbon-14 measurement of very small samples

International Nuclear Information System (INIS)

Sayre, E.V.; Harbottle, G.; Stoenner, R.W.; Otlet, R.L.; Evans, G.V.

1981-01-01

Two recent developments are: the first is the mass-spectrometric separation of 14 C and 12 C ions, followed by counting of the 14 C, while the second is the extension of conventional proportional counter operation, using CO 2 as counting gas, to very small counters and samples. Although the second method is slow (months of counting time are required for 10 mg of carbon) it does not require operator intervention and many samples may be counted simultaneously. Also, it costs only a fraction of the capital expense of an accelerator installation. The development, construction and operation of suitable small counters are described, and results of three actual dating studies involving milligram scale carbon samples will be given. None of these could have been carried out if conventional, gram-sized samples had been needed. New installations, based on the use of these counters, are under construction or in the planning stages. These are located at Brookhaven Laboratory, the National Bureau of Standards (USA) and Harwell (UK). The Harwell installation, which is in advanced stages of construction, will be described in outline. The main significance of the small-counter method is, that although it will not suffice to measure the smallest (much less than 10 mg) or oldest samples, it will permit existing radiocarbon laboratories to extend their capability considerably, in the direction of smaller samples, at modest expense

Application of the pulse-rise-time discriminator for background noise decreasing in proportional x-ray counters

International Nuclear Information System (INIS)

Goganov, D.A.; Guslina, A.G.; Korolev, V.F.; Lozinskij, B.S.; Sklyankin, V.A.

1977-01-01

The intrinsic background of commercial rising edge discriminator - based proportional counters has been measured. The block-diagram of the experimental apparatus comprises the detector to be tested, a charge-sensitive amplifier with an amplitude analyzer, a rising edge discriminator (RED) and a scaling device. The rising edges have been analyzed in the range between 0.2 to 0.7 of the pulse amplitude. The RED threshold has been preset to cut off all the edges longer than those of 55 Fe (to register 87% of the 55 Fe quanta). It has been found that by limiting the amplitude discriminator window to +-20% and using a RED the background of commercial counters can be reduced by about an order

An array of low-background 3He proportional counters for theSudbury Neutrino Observatory

Energy Technology Data Exchange (ETDEWEB)

Amsbaugh, J.F.; Anaya, J.M.; Banar, J.; Bowles, T.J.; Browne,M.C.; Bullard, T.V.; Burritt, T.H.; Cox-Mobrand, G.A.; Dai, X.; H.Deng,X.; Di Marco, M.; Doe, P.J.; Dragowsky, M.R.; Duba, C.A.; Duncan, F.A.; Earle, E.D.; Elliott, S.R.; Esch, E.-I.; Fergani, H.; Formaggio, J.A.; Fowler, M.M.; Franklin, J.E.; Geissbuehler, P.; Germani, J.V.; Goldschmidt, A.; Guillian, E.; Hallin, A.L.; Harper, G.; Harvey, P.J.; Hazama, R.; Heeger, K.M.; Heise, J.; Hime, A.; Howe, M.A.; Huang, M.; Kormos, L.L.; Kraus, C.; Krauss, C.B.; Law, J.; Lawson, I.T.; Lesko,K.T.; Loach, J.C.; Majerus, S.; Manor, J.; McGee, S.; Miknaitis, K.K.S.; Miller, G.G.; Morissette, B.; Myers, A.; Oblath, N.S.; O' Kee, H.M.; Ollerhead, R.W.; Peeters, S.J.M.; Poon, A.W.P.; Prior, G.; Reitzner,S.D.; Rielage, K.; Robertson, R.G.H.; Skensved, P.; Smith, A.R.; Smith,M.W.E.; Steiger, T.D.; Stonehill,L.C.; Thornewell, P.M.; Tolich, N.; VanDevender, B.A.; VanWechel, T.D.; Wall, B.L.; Tseung, H.W.C.; Wendland,J.; West, N.; Wilhelmy, J.B.; Wilkerson, J.F.; Wouters, J.M.

2007-02-01

An array of Neutral-Current Detectors (NCDs) has been builtin order to make a unique measurement of the total active ux of solarneutrinos in the Sudbury Neutrino Observatory (SNO). Data in the thirdphase of the SNO experiment were collected between November 2004 andNovember 2006, after the NCD array was added to improve theneutral-current sensitivity of the SNO detector. This array consisted of36 strings of proportional counters lled with a mixture of 3He and CF4gas capable of detecting the neutrons liberated by the neutrino-deuteronneutral current reaction in the D2O, and four strings lled with a mixtureof 4He and CF4 gas for background measurements. The proportional counterdiameter is 5 cm. The total deployed array length was 398 m. The SNO NCDarray is the lowest-radioactivity large array of proportional countersever produced. This article describes the design, construction,deployment, and characterization of the NCD array, discusses theelectronics and data acquisition system, and considers event signaturesand backgrounds.

Performance tests and comparison of microdosimetric measurements with four tissue-equivalent proportional counters in scanning proton therapy

Czech Academy of Sciences Publication Activity Database

Farah, J.; De Saint-Hubert, M.; Mojzeszek, N.; Chiriotti, S.; Gryzinski, M.; Ploc, Ondřej; Trompier, F.; Turek, Karel; Vanhavere, F.; Olko, P.

2017-01-01

Roč. 96, JAN (2017), s. 42-52 ISSN 1350-4487 EU Projects: European Commission(XE) 662287 - CONCERT Institutional support: RVO:61389005 Keywords : tissue-equivalent proportional counters * microdosimetry * proton therapy * stray neutrons and prothons Subject RIV: JF - Nuclear Energetics OBOR OECD: Nuclear related engineering Impact factor: 1.442, year: 2016

A G/NARRLI Effort. Measuring the Ionization Yield of Low-Energy Nuclear Recoils in Liquid Argon

Energy Technology Data Exchange (ETDEWEB)

Joshi, Tenzing Henry Yatish [Univ. of California, Berkeley, CA (United States)

2014-01-01

Liquid argon has long been used for particle detection due to its attractive drift properties, ample abundance, and reasonable density. The response of liquid argon to lowenergy O(10² -10⁴4 eV) interactions is, however, largely unexplored. Weakly interacting massive particles such as neutrinos and hypothetical dark-matter particles (WIMPs) are predicted to coherently scatter on atomic nuclei, leaving only an isolated low-energy nuclear recoil as evidence. The response of liquid argon to low-energy nuclear recoils must be studied to determine the sensitivity of liquid argon based detectors to these unobserved interactions. Detectors sensitive to coherent neutrino-nucleus scattering may be used to monitor nuclear reactors from a distance, to detect neutrinos from supernova, and to test the predicted behavior of neutrinos. Additionally, direct detection of hypothetical weakly interacting dark matter would be a large step toward understanding the substance that accounts for nearly 27% of the universe. In this dissertation I discuss a small dual-phase (liquid-gas) argon proportional scintillation counter built to study the low-energy regime and several novel calibration and characterization techniques developed to study the response of liquid argon to low-energy O(10² -10⁴ eV) interactions.

Identification of relativistic charged particles by means of ionisation energy loss in proportional counters

International Nuclear Information System (INIS)

Bateman, J.E.

1978-12-01

A method is described of obtaining a useful degree of improvement in the particle discrimination capability of multiwire proportional counters. The normal multiple sampling technique using a suitable bias to combat the small magnitude of the relativistic rise in the ionization energy loss and the wide pulse height distributions obtained in thin gas counters requires a large number of samples for useful discrimination. In the method reported, this number is reduced by suppressing the delta ray contribution to the total charge pulse from the anode wire. A monte carlo model convoluting the 'delta ray suppressed' data from a one sample detector shows that when it is required to separate pions and electrons at 1 GeV/C with a detection efficiency for the electron of 90%, a 'suppressor' circuit can achieve a pion rejection ratio of 250:1 with 82 samples, whereas the truncated mean approach (lowest 70% of samples) requires 100 samples. (UK)

Application of digital waveform processing to position-sensitive proportional counter

International Nuclear Information System (INIS)

Takenaka, Yasuto; Uritani, Akira; Mori, Chizuo

1995-01-01

In a charge-division type position-sensitive proportional counter (PSPC) with an anode wire of small resistance, a reflected component from an opposite end and thermal noise involved in signals deteriorate the position resolution of the PSPC. A digital waveform processing method was applied to the reduction of these undesirable effects by skillfully utilizing their signal characteristics that can be observed as inversely correlative signals between two-output signals from both sides of the PSPC. The digital waveform processing could improve the position resolution compared to a conventional pulse height processing method with analog filters. When the digital waveform processing was applied to signals of an equivalent circuit simulating the PSPC, the position resolutions defined by the full width at half maximum were improved to about 30% of those of conventional analog pulse processing. In the case of an actual PSPC, the position resolutions by the digital waveform processing were improved by 4-10% as compared with those of conventional pulse height processing. (author)

Construction of a self-supporting tissue-equivalent dividing wall and operational characteristics of a coaxial double-cylindrical tissue-equivalent proportional counter

International Nuclear Information System (INIS)

Saion, E.B.; Watt, D.E.

1994-01-01

An additional feature incorporated in a coaxial double-cylindrical tissue-equivalent proportional counter, is the presence of a common tissue-equivalent dividing wall between the inner and outer counters of thickness equivalent to the corresponding maximum range of protons at the energy of interest. By appropriate use of an anti-coincidence arrangement with the outer counter, the inner counter could be used to discriminate microdosimetric spectra of neutrons at the desired low energy range from those of the faster neutrons. The construction of an A-150 self-supporting tissue-equivalent dividing wall and an anti-coincidence unit are described. Some operational characteristic tests have been performed to determine the operation of the new microdosimeter. (author)

Determination of the influence of asymmetry of the electric field distribution in gaseous proportional counters on their signal amplitude

International Nuclear Information System (INIS)

Jagusztyn, W.

1976-01-01

A method is described of establishing the influence of the asymmetry of the electric field distribution in gaseous proportional counters on the amplitude of their voltage signal. A numerical evaluation of this effect demands performing calculations of the electric field in the vicinity of the anode. Using the described method of numerical solution of the Laplace equation in polar coordinates with logarythmically scaled radial dimension, it is possible to achieve the required accuracy. In the calculations of differences in amplitudes of voltage signals, for chosen trajektories of electrons liberated in the process of primary ionization, changes in the gaseous amplification factors and drift velocities of positive ions are taken into account. Experimental results prove the validity of presented theory. The results obtained are accurate enough to be applied to the design of proportional counters of non-cylindrical geometries. (author)

A technique for searching for the 2K capture in {sup 124}Xe with a copper proportional counter

Energy Technology Data Exchange (ETDEWEB)

Gavrilyuk, Yu. M.; Gangapshev, A. M.; Kazalov, V. V.; Kuzminov, V. V. [Russian Academy of Sciences, Institute for Nuclear Research (Russian Federation); Panasenko, S. I.; Ratkevich, S. S. [Karazin Kharkiv National University (Ukraine); Tekueva, D. A., E-mail: t.jami.a@mail.ru; Yakimenko, S. P. [Russian Academy of Sciences, Institute for Nuclear Research (Russian Federation)

2015-12-15

An experimental technique for searching for the 2K capture in {sup 124}Xe with a large low-background copper proportional counter is described. Such an experiment is conducted at the Baksan Neutrino Observatory of the Institute for Nuclear Research of the Russian Academy of Sciences. The experimental setup is located in the Low-Background Deep-Level Laboratory at a depth of 4900 m.w.e., where the flux of muons of cosmic rays is suppressed by a factor of 10{sup 7} relative to that at the Earth’s surface. The setup incorporates a proportional counter and low-background shielding (18 cm of copper, 15 cm of lead, and 8 cm of borated polyethylene). The results of processing the data obtained in 5 months of live measurement time are presented. A new limit on the half-life of {sup 124}Xe with respect to the 2K capture is set at the level of 2.5 × 10{sup 21} years.

The performance of the curved grid gas proportional scintillation counter in X-ray spectrometry

International Nuclear Information System (INIS)

Santos, J.M.F. dos; Bento, A.C.S.S.M.; Conde, C.A.N.

1994-01-01

The performance of a curved grid gas proportional scintillation counter filled with xenon at 1100 mbar and having a 25 mm diameter window is evaluated for X-rays in the 1-11 keV energy range. Energy resolutions of 8.0% were obtained for a 5.9 keV parallel X-ray beam entering the detector through the full size window. The variation of the energy resolution with the X-ray energy is studied and X-ray fluorescence spectra for samples like industrial coal, painted porcelain and car lubrication oil, are presented. (orig.)

Irradiation of Methane by Recoiling Fission-Fragments

Energy Technology Data Exchange (ETDEWEB)

Hall, G. R.; Galley, M. R. [Imperial College of Science and Technology, London (United Kingdom)

1963-11-15

Pure methane gas (containing <0.003% oxygen and <5 mg H{sub 2}O per m{sup 3}) has been irradiated at pressures ranging from 5 to 50 atmospheres pressure and at 30{sup o}C with recoiling fission - fragments. The gas is contained in a silica ampoule of volume about 9 cm{sup 3} and which also contains a platinum cylinder coated on the inside with 0.5 mg/cm{sup 2} highly enriched uranium oxide. When the ampoule is irradiated in a nuclear reactor with thermal neutrons, about half the fission-fragments recoil from the uranium and dissipate their energy in the methane. In a typical irradiation, methane at 10 atm pressure receives a dose of 5 x 10{sup 21} eV at an integrated reactor flux of 5 x 10{sup 15} neutrons/cm{sup 2}. Neutron flux i s measured by means of a gold-foil flux monitor. The activity of the Au{sup 198} is counted in a 4 {pi} proportional counter. The irradiation products have been detected by using beta-ionization detectors for gas-phase chromatography with suitable columns. The following products have been found: hydrogen, ethane, propane, n-butane, isobutane, n-pentane, iso-pentane, neo-pentane, the seven hexanes. Traces of higher hydrocarbons are undoubtedly present but the analysis of these has not been attempted. Hydrogen is present in greatest yield and the yields of the hydrocarbons decrease in the order given above. Despite previously reported yields of ethylene (G-value-0.1) from gamma and fast - electron irradiations, no ethylene or other unsaturated products have been detected in this work. It would have been possible to detect 10 ppm in the products. This is to be expected as any double bonds which may be produced would almost immediately be hydrogenated by the hydrogen present. Yields for hydrogen, ethane and propane lie within the range of values that have been reported by other workers for gamma and fast electron irradiations. (author)

KEhD-1 Debye-Sherrar camera with a coordinate proportional counter

International Nuclear Information System (INIS)

Ageev, O.I.; Glazova, L.P.; Goganov, D.A.; Rejzis, B.M.; Syrkin, M.G.

1985-01-01

An arrangement of the KEhD-1 Debye-Sherrar camera, in which the advantages of a proportional counter are combined with the wide range of simultaneous image recording is described. The camera consists of an X-ray tube unit with the URS-0.1 source, a linear coordinate detector with resistive-capacity coding, a signal transducer and the MK-1 multichannel system for data acquisition and processing based on the ''Uskra-1256'' computer. The counting rate of X-ray pulses is > 5x10 4 s -1 , energy resolution for the CuKsub(α) line constitutes 20%, spatial resolution equals 150 μm, detection efficiency constitutes not less than 64%. The range of the detector displacement varies from -30 deg to +130 deg. The information obtained by means of the camera may be output to a display, a plotter, a numeric printer or a magnetic tape

Recent improvements to RC-line encoded position-sensitive proportional counters

International Nuclear Information System (INIS)

Borkowski, C.J.; Kopp, M.K.

1977-01-01

Continuing research on the principles of position encoding with RC lines has advanced the design of position-sensitive proportional counters (PSPCs) to meet the requirements for high count rates (>10 5 counts/sec) and good spatial resolution (>10 4 spatial elements) in small-angle scattering experiments with x rays and neutrons. Low-noise preamplifiers were developed with pole-zero cancellation in the feedback circuit and modular linear amplifiers with passive RCL shaping which, compared to previous designs, reduce output saturation at high count rates approx.20 times and shorten the position signal processing time to 2 ) for low-energy ( 800 x 800 mm 2 ) for the measurement of small-angle scattering with neutrons. The method of electronic thickness discrimination was applied to change the effective thickness of an area PSPC from 12 to 2 cm whenever the molybdenum target of an x-ray generator was changed to a copper target. This thickness adjustment increased the signal-to-background ratio by a factor of approx.6 for the 8-keV photons from the copper target, while maintaining a >90% detection efficiency

A suspended boron foil multi-wire proportional counter neutron detector

Energy Technology Data Exchange (ETDEWEB)

Nelson, Kyle A.; Edwards, Nathaniel S.; Hinson, Niklas J.; Wayant, Clayton D.; McGregor, Douglas S.

2014-12-11

Three natural boron foils, approximately 1.0 cm in diameter and 1.0 µm thick, were obtained from The Lebow Company and suspended in a multi-wire proportional counter. Suspending the B foils allowed the alpha particle and Li ion reaction products to escape simultaneously, one on each side of the foil, and be measured concurrently in the gas volume. The thermal neutron response pulse-height spectrum was obtained and two obvious peaks appear from the 94% and 6% branches of the {sup 10}B(n,α){sup 7}Li neutron reaction. Scanning electron microscope images were collected to obtain the exact B foil thicknesses and MCNP6 simulations were completed for those same B thicknesses. Pulse-height spectra obtained from the simulations were compared to experimental data and matched well. The theoretical intrinsic thermal–neutron detection efficiency for enriched {sup 10}B foils was calculated and is presented. Additionally, the intrinsic thermal neutron detection efficiency of the three natural B foils was calculated to be 3.2±0.2%.

A suspended boron foil multi-wire proportional counter neutron detector

Science.gov (United States)

Nelson, Kyle A.; Edwards, Nathaniel S.; Hinson, Niklas J.; Wayant, Clayton D.; McGregor, Douglas S.

2014-12-01

Three natural boron foils, approximately 1.0 cm in diameter and 1.0 μm thick, were obtained from The Lebow Company and suspended in a multi-wire proportional counter. Suspending the B foils allowed the alpha particle and Li ion reaction products to escape simultaneously, one on each side of the foil, and be measured concurrently in the gas volume. The thermal neutron response pulse-height spectrum was obtained and two obvious peaks appear from the 94% and 6% branches of the 10B(n,α)7Li neutron reaction. Scanning electron microscope images were collected to obtain the exact B foil thicknesses and MCNP6 simulations were completed for those same B thicknesses. Pulse-height spectra obtained from the simulations were compared to experimental data and matched well. The theoretical intrinsic thermal-neutron detection efficiency for enriched 10B foils was calculated and is presented. Additionally, the intrinsic thermal neutron detection efficiency of the three natural B foils was calculated to be 3.2±0.2%.

Digital signal processing for He3 proportional counter

International Nuclear Information System (INIS)

Zeynalov, Sh.S.; Ahmadov, Q.S.

2010-01-01

Full text : Data acquisition systems for nuclear spectroscopy have traditionally been based on systems with analog shaping amplifiers followed by analog-to-digital converters. Recently, however, new systems based on digital signal processing make possible to replace the analog shaping and timing circuitry the numerical algorithms to derive properties of the pulse such as its amplitude. DSP is a fully numerical analysis of the detector pulse signals and this technique demonstrates significant advantages over analog systems in some circumstances. From a mathematical point of view, one can consider the signal evolution from the detector to the ADC as a sequence of transformations that can be described by precisely defined mathematical expressions. Digital signal processing with ADCs has the possibility to utilize further information on the signal pulses from radiation detectors. In the experiment each step of the signal generation in the 3He filled proportional counter was described using digital signal processing techniques (DSP). The electronic system has consisted of a detector, a preamplifier and a digital oscilloscope. The pulses from the detector were digitized using a digital storage oscilloscope. This oscilloscope allowed signal digitization with accuracy of 8 bit (256 levels) and with frequency of up to 5 * 10 8 samples/s. As a neutron source was used Cf-252. To obtain detector output current pulse I(t) created by the motions of the ions/electrons pairs was written an algorithm which can easily be programmed using modern computer programming languages.

Alpha–beta monitoring system based on pair of simultaneous Multi-Wire Proportional Counters

Energy Technology Data Exchange (ETDEWEB)

Wengrowicz, U.; Amidan, D. [Department of Nuclear Engineering, Ben Gurion University of the Negev, Beer-Sheva 84105 (Israel); NRC-Negev, P.O. Box 9001, Beer-Sheva 84190 (Israel); Orion, I. [Department of Nuclear Engineering, Ben Gurion University of the Negev, Beer-Sheva 84105 (Israel)

2016-08-11

A new approach for a simultaneous alpha–beta Multi-wire Proportional Counter (MWPC) is presented. The popular approach for alpha–beta monitoring systems consists of a large area MWPC using noble gas flow such as Argon Methane. This method of measurement is effective but requires large-scale and expensive maintenance due to the needs of gas flow control and periodic replacements. In this work, a pair of simultaneous MWPCs for alpha–beta measuring is presented. The developed detector consists of a sealed gas MWPC sensor for beta particles, behind a free air alpha sensor. This approach allows effective simultaneous detection and discrimination of both alpha and beta radiation without the maintenance cost noble gas flow required for unsealed detectors.

Conception of a New Recoil Proton Telescope for Real-Time Neutron Spectrometry in Proton-Therapy

Science.gov (United States)

Combe, Rodolphe; Arbor, Nicolas; el Bitar, Ziad; Higueret, Stéphane; Husson, Daniel

2018-01-01

Neutrons are the main type of secondary particles emitted in proton-therapy. Because of the risk of secondary cancer and other late occurring effects, the neutron dose should be included in the out-of-field dose calculations. A neutron spectrometer has to be used to take into account the energy dependence of the neutron radiological weighting factor. Due to its high dependence on various parameters of the irradiation (beam, accelerator, patient), the neutron spectrum should be measured independently for each treatment. The current reference method for the measurement of the neutron energy, the Bonner Sphere System, consists of several homogeneous polyethylene spheres with increasing diameters equipped with a proportional counter. It provides a highresolution reconstruction of the neutron spectrum but requires a time-consuming work of signal deconvolution. New neutron spectrometers are being developed, but the main experimental limitation remains the high neutron flux in proton therapy treatment rooms. A new model of a real-time neutron spectrometer, based on a Recoil Proton Telescope technology, has been developed at the IPHC. It enables a real-time high-rate reconstruction of the neutron spectrum from the measurement of the recoil proton trajectory and energy. A new fast-readout microelectronic integrated sensor, called FastPixN, has been developed for this specific purpose. A first prototype, able to detect neutrons between 5 and 20 MeV, has already been validated for metrology with the AMANDE facility at Cadarache. The geometry of the new Recoil Proton Telescope has been optimized via extensive Geant4 Monte Carlo simulations. Uncertainty sources have been carefully studied in order to improve simultaneously efficiency and energy resolution, and solutions have been found to suppress the various expected backgrounds. We are currently upgrading the prototype for secondary neutron detection in proton therapy applications.

Methods of calculus for neutron spectrometry in proportional counters; Metodos de calculo para espectrometria de neutrones en contadores proporcionales

Energy Technology Data Exchange (ETDEWEB)

Butragueno, J L; Blazquez, J B; Barrado, J M

1976-07-01

Response functions for cylindrical proportional counters with hydrogenated gases have been determined, taking in account only wall effect, by means of two independent calculus methods. One of them is a Monte Carlo application and the other one analytica at all. Results of both methods have been compared. (Author)

Numerical determination of the amplification of a cylindrical proportional counter operating at low pressure. Application to nano-dosimetry

International Nuclear Information System (INIS)

Moutarde, Cyrille

1994-01-01

This work is devoted to a study of proportional counters used to measure the energy deposition in micrometer biological sites. Tissue equivalent gas filling improve typical operating mode of those counters. Specially, the extension of the multiplication zone becomes important at low pressures. A Monte Carlo simulation has been used to study the behaviour of an electron swarm in the sensitive volume. The calculations show that electrons are not in equilibrium with the applied electric field in this geometry. The influence of the gradient field and the rotation of the electrons around the anode wire has been studied carefully. The importance of non-equilibrium effects on the theoretical amplification calculated through the ionisation coefficient has been confirmed by experimental investigations. The statistical fluctuations of multiplication process has been calculated by the determination of avalanche spectra at the anode. Resolution of an ultra-miniature counter have been calculated to improve technological limitations of experimental nanodosimetry. (author) [fr

Counter support for WA35

CERN Multimedia

CERN PhotoLab

1977-01-01

This assembly was equipped with 78 counters, each consisting of a lucite cone, to produce Cerenkov light, and a CsI scintillator plate of 3 mm thickness glued on the face of the cone. The experiment WA35 was set-up in the s1 beam (West Hall) by the Darmstadt-Heidelberg-Virginia-Warsaw Collaboration to measure angular distributions and multiplicities of pions and recoil protons produced by hadrons interacting in nuclei. (See Annual Report 1976 p. 39)

Characteristics of proportional counters used in X-ray radiometric analysis

International Nuclear Information System (INIS)

Mamikonyan, S.V.; Martishchenko, L.G.; Mel'ttser, L.V.

1972-01-01

Counters with extended (up to 10 cm 2 ) apertres have been described and the results obtained are presented. CPM-15 and CPM-16 counters are intended for sensoring and spectral analysis of X-rays in the range of 2.5 to 23 and 2.5 to 15 keV, respectively. The only difference is in the gas composition. The CPM-15 counter is filled with 90 per cent xenon plus 10 per cent methane used as a quenching dopant. The CPM-16 is filled with 90 per cent argon and 10 per cent methane. The life time is 10 10 pulses at 1800 V for CPM-16 and at 2200 V for CPM-15

Use of tissue equivalent proportional counters to characterize radiation quality on the space shuttle

International Nuclear Information System (INIS)

Braby, L.A.; Conroy, T.J.; Elegy, D.C.; Brackenbush, L.W.

1992-04-01

Tissue equivalent proportional counters (TEPC) are essentially cavity ionization chambers operating at low pressure and with gas gain. A small, battery powered, TEPC spectrometer, which records lineal energy spectra at one minute intervals, has been used on several space shuttle missions. The data it has collected clearly show the South Atlantic anomaly and indicate a mean quality factor somewhat higher than expected. An improved type of instrument has been developed with sufficient memory to record spectra at 10 second intervals, and with increased resolution for low LET events. This type of instrument will be used on most future space shuttle flights and in some international experiments

Development of multiwire proportional chambers

CERN Multimedia

Charpak, G

1969-01-01

It has happened quite often in the history of science that theoreticians, confronted with some major difficulty, have successfully gone back thirty years to look at ideas that had then been thrown overboard. But it is rare that experimentalists go back thirty years to look again at equipment which had become out-dated. This is what Charpak and his colleagues did to emerge with the 'multiwire proportional chamber' which has several new features making it a very useful addition to the armoury of particle detectors. In the 1930s, ion-chambers, Geiger- Muller counters and proportional counters, were vital pieces of equipment in nuclear physics research. Other types of detectors have since largely replaced them but now the proportional counter, in new array, is making a comeback.

Digital signal processing for He3 proportional counter

International Nuclear Information System (INIS)

Ahmadov, Q.S.; Institute of Radiation Problems, ANAS, Baku

2011-01-01

Full text: Data acquisition systems for nuclear spectroscopy have traditionally been based on systems with analog shaping amplifiers followed by analog-to-digital converters. Recently, however, new systems based on digital signal processing allow us to replace the analog shaping and timing circuitry the numerical algorithms to derive properties of the pulse such as its amplitude. DSP is a fully numerical analysis of the detector pulse signals and this technique demonstrates significant advantages over analog systems in some circumstances. From a mathematical point of view, one can consider the signal evolution from the detector to the ADC as a sequence of transformations that can be described by precisely defined mathematical expressions.Digital signal processing with ADCs has the possibility to utilize further information on the signal pulses from radiation detectors [1] [2]. In the experiment each step of the signal generation in the 3He filled proportional counter was described using digital signal processing techniques (DSP). The electronic system has consisted of a detector, a preamplifier and a digital oscilloscope. The pulses from the detector were digitized using a OTSZS-02 (250USB)-4 digital storage oscilloscope from ZAO R UDNEV-SHILYAYEV . This oscilloscope allowed signal digitization with accuracy of 8 bit(256 levels) and with frequency of up to 5.10''8 samples/s. As a neutron source was used Cf-252.To obtain detector output current pulse I(t) created by the motions of the ions/electrons pairs was written an algorithm which can easily be programmed using modern computer programming languages

First results of a simultaneous measurement of tritium and 14C in an ultra-low-background proportional counter for environmental sources of methane

Energy Technology Data Exchange (ETDEWEB)

Mace, Emily K.; Aalseth, Craig E.; Day, Anthony R.; Hoppe, Eric W.; Keillor, Martin E.; Moran, James J.; Panisko, Mark E.; Seifert, Allen; Tatishvili, Gocha; Williams, Richard M.

2016-02-01

Abstract Simultaneous measurement of tritium and 14C would provide an added tool for tracing organic compounds through environmental systems and is possible via beta energy spectroscopy of sample-derived methane in internal-source gas proportional counters. Since the mid-1960’s atmospheric tritium and 14C have fallen dramatically as the isotopic injections from above-ground nuclear testing have been diluted into the ocean and biosphere. In this work, the feasibility of simultaneous tritium and 14C measurements via proportional counters is revisited in light of significant changes in both the atmospheric and biosphere isotopics and the development of new ultra-low-background gas proportional counting capabilities for small samples (roughly 50 cc methane). A Geant4 Monte Carlo model of a Pacific Northwest National Laboratory (PNNL) proportional counter response to tritium and 14C is used to analyze small samples of two different methane sources to illustrate the range of applicability of contemporary simultaneous measurements and their limitations. Because the two methane sources examined were not sample size limited, we could compare the small-sample measurements performed at PNNL with analysis of larger samples performed at a commercial laboratory. The dual-isotope simultaneous measurement is well matched for methane samples that are atmospheric or have an elevated source of tritium (i.e. landfill gas). For samples with low/modern tritium isotopics (rainwater), commercial separation and counting is a better fit.

Single channel analog pulse processor Asic for gas proportional counters and SI detector

International Nuclear Information System (INIS)

Chandratre, V.B.; Sarkar, Soumen; Kataria, S.K.; Viyogi, Y.P.

2005-01-01

The paper presents the design and development of a single channel pulse processor in short Singleplex ASIC targeted for gas proportional counters/Si detectors. The design is optimized for the dynamic range of +500 fC to -500 fC with provision for externally adjusted pole-zero cancellation. A dedicated filter based on the de-convolution principle is used for the cancellation of the long hyperbolic signal tail produced by the slow drift of ions, typical in gas proportional with the filter time constants derived from the actual detector input signal shape. The pole-zero adjustment can be done by external dc voltage to achieve perfect base-line recovery to 1% after 5 μs. The simulated 0 pf noise is 500 e - rms for the peaking time of 1.2 μs with noise slope of 7e - -. The gain is 3.4 mv/fC over the entire linear dynamic range with power dissipation of 13 mW. This design is a modified version of Indiplex chip with features dynamic range equal gain on both polarities with nearly same noise and serves as diagnostic chip for Indiplex. The chip can be used for radiation monitoring instruments. (author)

Fast neutron spectroscopy by gas proton-recoil methods at the light water reactor pressure vessel simulator

International Nuclear Information System (INIS)

Rogers, J.W.

1980-10-01

Fast neutron spectrum measurements were made in a Light Water Reactor (LWR) Pressure Vessel Simulator (PVS) to provide neutron spectral definition required to appropriately perform and interpret neutron dosimetry measurements related to fast neutron damage in LWR-PV steels. Proton-recoil proportional counter methods using hydrogen and methane gas-filled detectors were applied to obtain the proton spectra from which the neutron spectra were derived. Cylindrical and spherical geometry detectors were used to cover the neutron energy range between 50 keV and 2 MeV. Results show that the neutron spectra shift in energy distribution toward lower energy between the front and back of a PVS. The relative neutron flux densities increase in this energy range with increasing thickness of the steel. Neutron spectrum fine structure shapes and changes are observed. These results should assist in the generation of more accurate effective cross sections and fluences for use in LWR-PV fast neutron dosimetry and materials damage analyses

Long life boron-lined proportional counters fitted to the start-up range of the nuclear reactors

International Nuclear Information System (INIS)

Dauphin, G.; Duchene, J.

1983-03-01

CEA has been engaged in a research and development program in technical cooperation with RTC, to improve the life time of the boron lined proportional counters used for PWR's start up. The present report is a synthesis of these works. The processes by which the discrimination curves show a shift in count rate versus the neutron fluences are described and, the possible ways to get improved performances and the tests performed on the different prototypes are presented. Analysis of the results is given [fr

Radiation protection instruments based on tissue equivalent proportional counters: Part II of an international intercomparison

International Nuclear Information System (INIS)

Alberts, W.G.; Dietz, E.; Guldbakke, S.; Kluge, H.; Schumacher, H.

1988-04-01

This report describes the irradiation conditions and procedures of Part II of an international intercomparison of tissue-equivalent proportional counters used for radiation protection measurements. The irradiations took place in monoenergetic reference neutron fields produced by the research reactor and accelerator facilities of the PTB Braunschweig in the range from thermal neutrons to 14.8 MeV. In addition measurements were performed in 60 Co and D 2 O-moderated 252 Cf radiation fields. Prototype instruments from 7 European groups were investigated. The results of the measurements are summarized and compared with the reference data of the irradiations. (orig.) [de

Absolute determination of radiation bursts and of proportional counters space charge effect through the influence method

International Nuclear Information System (INIS)

Rios, I.J.; Mayer, R.E.

2016-01-01

When proportional counters are employed in charge integration mode to determine the magnitude of a radiation pulse, so intense that individual detection events take place in a time too short to produce individual output pulses, mostly in pulsed neutron sources, the strong build-up of positive space charge reduces the electric multiplication factor of the proportional detector. Under such conditions the ensuing measurement underestimates the amount of radiation that interacted with the detector. If the geometric characteristics, the filling gas pressure and the voltage applied to that detector are known, it becomes possible to apply an analytical correction method to the measurement. In this article we present a method that allows to determine the absolute value of the detected radiation burst without the need to know the characteristics of the employed detectors. It is necessary to employ more than one detector, taking advantage of the Influence Method. The “Influence Method” is conceived for the absolute determination of a nuclear particle flux in the absence of known detector efficiency and without the need to register coincidences of any kind. This method exploits the influence of the presence of one detector in the count rate of another detector, when they are placed one behind the other and define statistical estimators for the absolute number of incident particles and for the efficiency (Rios and Mayer, 2015 [1,2]). Its practical implementation in the measurement of a moderated neutron flux arising from an isotopic neutron source was exemplified in (Rios and Mayer, 2016 [3]) and the extension for multiple detectors in (Rios and Mayer 2016 [4]). - Highlights: • Absolute determination of radiation burst. • Proportional counters space charge effect. • Radiation measurements on pulsed devices.

A powerful, low-cost histogramming memory for digital radiography with multi-wire proportional counters

International Nuclear Information System (INIS)

Bateman, J.E.; Locke, C.E.R.; Ferrari, C.A.

1986-01-01

A powerful, low-cost histogramming memory for digital radiograph with multi-wire proportional counter is described. The memory is based on a commercial video display device coupled to an Apple II microcomputer which, at a total cost of around 2500 pounds gives a system with 512 x 512 pixel resolution and a counting range of 4095 counts per pixel. The system can take data at rates of up to 5000 Hz while providing a live-time display. No hardware modifications are necessary, the comprehensive storage and display facilities being implemented in a combined package of BASIC and ASSEMBLER software. An ACCELERATOR coprocessor card is used to enhance the performance of the system. (author)

Dual-chamber/dual-anode proportional counter incorporating an intervening thin-foil solid neutron converter

International Nuclear Information System (INIS)

Boatner, Lynn A.; Neal, John S.; Blackston, Matthew A.; Kolopus, James A.; Ramey, Joanne O.

2012-01-01

A dual-chamber/dual-anode gas proportional counter utilizing thin solid 6 LiF or 10 B neutron converters coated on a 2-micon-thick Mylar film that is positioned between the two counter chambers and anodes has been designed, fabricated, and tested using a variety of fill gases—including naturally abundant helium. In this device, neutron conversion products emitted from both sides of the coated converter foil are detected—rather than having half of the products absorbed in the wall of a conventional tube-type counter where the solid neutron converter is deposited on the tube wall. Geant4-based radiation transport calculations were used to determine the optimum neutron converter coating thickness for both isotopes. Solution methods for applying these optimized-thickness coatings on a Mylar film were developed that were carried out at room temperature without any specialized equipment and that can be adapted to standard coating methods such as silk screen or ink jet printing. The performance characteristics of the dual-chamber/dual-anode neutron detector were determined for both types of isotopically enriched converters. The experimental performance of the 6 LiF-converter-based detector was described well by modeling results from Geant4. Additional modeling studies of multiple-foil/multiple-chamber/anode configurations addressed the basic issue of the relatively longer absorption range of neutrons versus the shorter range of the conversion products for 6 LiF and 10 B. Combined with the experimental results, these simulations indicate that a high-performance neutron detector can be realized in a single device through the application of these multiple-foil/solid converter, multiple-chamber detector concepts.

Helium-filled proportional counter and its operation mechanism at low temperatures

CERN Document Server

Isozumi, Y; Kishimoto, S

2002-01-01

The operation mechanism of helium-filled proportional counter (HFPC) at about 4.2 K is explained. Unstable behavior of HFPC is caused by releasing secondary-electron from the cathode by four kinds of active particles such as He sub n sup + , non-resonance photon from excited helium atom, non-resonance photon from He sub 2 sup * (A sup 1 Su sup +) and He sub 2 sup m (a sup 3 Su sup +). On experiments of HFPC behavior at low temperature, the following facts were observed; 1) main charge formation process in the electron avalanche is direct ionization by electron without Hornbeck-Molnar process. Accordingly, the gas amplification factor becomes small at low temperature. 2) Stable helium cation is He sub 2 sup + at room temperature, but cluster at low temperature. Large after-pulse is observed in output signal depends on cluster ion. The probability of secondary-electron emission decreased. The gas gain increased with increasing anode voltage. 3) By decreasing reaction rate of atom and molecule collision at low t...

MCNP modelling of the wall effects observed in tissue-equivalent proportional counters.

Science.gov (United States)

Hoff, J L; Townsend, L W

2002-01-01

Tissue-equivalent proportional counters (TEPCs) utilise tissue-equivalent materials to depict homogeneous microscopic volumes of human tissue. Although both the walls and gas simulate the same medium, they respond to radiation differently. Density differences between the two materials cause distortions, or wall effects, in measurements, with the most dominant effect caused by delta rays. This study uses a Monte Carlo transport code, MCNP, to simulate the transport of secondary electrons within a TEPC. The Rudd model, a singly differential cross section with no dependence on electron direction, is used to describe the energy spectrum obtained by the impact of two iron beams on water. Based on the models used in this study, a wall-less TEPC had a higher lineal energy (keV.micron-1) as a function of impact parameter than a solid-wall TEPC for the iron beams under consideration. An important conclusion of this study is that MCNP has the ability to model the wall effects observed in TEPCs.

Development of a parallel plate proportional counter TRD with suppressed sensitivity to ionization

International Nuclear Information System (INIS)

Solomey, N.; Krolak, P.; Graham, G.

1995-01-01

The development of a Parallel Plate Proportional Counter which has a highly suppressed sensitivity to ionization but retains a good X-ray signal to noise ratio is presented. Details of the laboratory development and actual beam tests showing the e/π rejection are described. Because of its insensitivity to ionization this type of detector can be useful in an environment where the number of minimum ionizing particles are high, but uninteresting; however, the detector is very sensitive to the highly localized electron cloud from converted X-rays making it ideal as a transition radiation X-ray detector. Thus, this detector only gives a signal for charged particles above TR threshold; all other particles below this threshold produce no TR X-rays giving only a pedestal-like signal. The system's potential performance for π/p separation in the intended neutral Hyperon experiment is evaluated

Qualitative and quantative analysis of some physical processes encountered in measurements of low level radon activity by means of proportional counter

International Nuclear Information System (INIS)

Bluszcz, A.; Moscicki, W.

1980-01-01

Physical model for absorption of radon and its decay products on the electrodes of the proportional counter filled with Rn-CO 2 mixture is presented. The results of calculations based on developed model are compared with observed changes of counting rate of radon and its decay products. (author)

Recoil ions

International Nuclear Information System (INIS)

Cocke, C.L.; Olson, R.E.

1991-01-01

The collision of a fast moving heavy ion with a neutral atomic target can produce very highly charged but slowly moving target ions. This article reviews experimental and theoretical work on the production and use of recoil ions beyond the second ionization state by beams with specific energies above 0.5 MeV/amu. A brief historical survey is followed by a discussion of theoretical approaches to the problem of the removal of many electrons from a neutral target by a rapid, multiply charged projectile. A discussion of experimental techniques and results for total and differential cross sections for multiple ionization of atomic and molecular targets is given. Measurements of recoil energy are discussed. The uses of recoil ions for in situ spectroscopy of multiply charged ions, for external beams of slow, highly charged ions and in ion traps are reviewed. Some possible future opportunities are discussed. (orig.)

Search of 2K(2ν) capture in 78 Kr and 124 Xe by means of wall-less proportional counters

International Nuclear Information System (INIS)

Volchenko, G.V.; Gavrilyuk, Yu.M.; Kuz'minov, V.V.; Osetrova, N.Ya.; Ratkevich, S.S.

1998-01-01

The technique of the experiment on the double two-neutrino K-capture search in isotopes of rare gases 78 Kr and 124 Xe is described. Multiwire wall-less proportional counters of a large volume are used in this experiment. Methods of decreasing the counter background noise in the energy range 10-100 keV are considered. These methods are based on the discrimination of events on the coordinate along the anode filament and the pulse rise time. The sensitivity of the experimental installation is estimated according to the half-life 78 Kr (1.2 x 10 21 years) and 124 Xe (2.6 x 10 20 years) with respect to the 2K(2ν) capture (68% certain level)

Errors in estimating neutron quality factor using lineal energy distributions measured in tissue-equivalent proportional counters

International Nuclear Information System (INIS)

Borak, T.B.; Stinchcomb, T.G.

1982-01-01

Neutron dose equivalent is obtained from quality factors which are defined in terms of LET. It is possible to estimate the dose averaged quality factor, antiQ, directly from distributions in lineal energy, y, that are measured in tissue-equivalent proportional counters. This eliminates a mathematical transformation of the absorbed dose from D(y) to D(L). We evaluate the inherent error in computing Q from D(y) rather than D(L) for neutron spectra below 4 MeV. The effects of neutron energy and simulated tissue diameters within a gas cavity are examined in detail. (author)

The Rutherford Appleton Laboratory's Mark I multiwire proportional counter positron camera

International Nuclear Information System (INIS)

Bateman, J.E.; Connolly, J.F.; Stephenson, R.; Tappern, G.J.; Flesher, A.C.

1984-01-01

A small (30 cmx30 cm) model of a proposed large aperture positron camera has been developed at Rutherford Appleton Laboratory. Based on multiwire proportional counter technology, it uses lead foil cathodes which function simultaneously as converters for the 511 keV gamma rays and readout electrodes for a delay line readout system. The detectors have been built up into a portable imaging system complete with a dedicated computer for data taking, processing and display. This has permitted evaluation of this type of positron imaging system in the clinical environment using both cyclotron generated isotopes ( 15 O, 11 C, 18 F, 124 I) and available isotopic generator systems ( 82 Rb, 68 Ga). AT RAL we provided a complete hardware system and sufficient software to permit our hospital based colleagues to generate useful images with the minimum of effort. A complete description of the system is given with performance figures and some of the images obtained in three hospital visits are presented. Some detailed studies of the imaging performance of the positron camera are reported which have bearing on the design of future, improved systems. (orig.)

Development and Characterization of Tissue Equivalent Proportional Counter for Radiation Monitoring in International Space Station

Directory of Open Access Journals (Sweden)

Uk-Won Nam

2013-06-01

Full Text Available Tissue equivalent proportional counter (TEPC can measure the Linear Energy Transfer (LET spectrum and calculate the equivalent dose for the complicated radiation field in space. In this paper, we developed and characterized a TEPC for radiation monitoring in International Space Station (ISS. The prototype TEPC which can simulate a 2 μm of the site diameter for micro-dosimetry has been tested with a standard alpha source (241Am, 5.5 MeV. Also, the calibration of the TEPC was performed by the 252Cf neutron standard source in Korea Research Institute of Standards and Science (KRISS. The determined calibration factor was kf = 3.59×10-7 mSv/R.

A model for the operation of helium-filled proportional counter at low temperatures near 4.2 K

International Nuclear Information System (INIS)

Masaoka, Sei; Katano, Rintaro; Kishimoto, Shunji; Isozumi, Yasuhito

2000-01-01

In order to understand the operation of helium-filled proportional counter (HFPC) from the standpoint of fundamental atomic and molecular processes, we have surveyed previous works on collision processes in discharged helium gas. By analyzing gas gain curve, after-pulses and discharge current experimentally observed at 4.2 K, the electron avalanche and the secondary electron emission from cathode have been related to the collision processes in helium. A simplified model for the HFPC operation at low temperatures near 4.2 K has been constructed with the related processes

The HERMES recoil detector

International Nuclear Information System (INIS)

Airapetian, A.; Belostotski, S.

2013-02-01

For the final running period of HERA, a recoil detector was installed at the HERMES experiment to improve measurements of hard exclusive processes in charged-lepton nucleon scattering. Here, deeply virtual Compton scattering is of particular interest as this process provides constraints on generalised parton distributions that give access to the total angular momenta of quarks within the nucleon. The HERMES recoil detector was designed to improve the selection of exclusive events by a direct measurement of the four-momentum of the recoiling particle. It consisted of three components: two layers of double-sided silicon strip sensors inside the HERA beam vacuum, a two-barrel scintillating fibre tracker, and a photon detector. All sub-detectors were located inside a solenoidal magnetic field with an integrated field strength of 1Tm. The recoil detector was installed in late 2005. After the commissioning of all components was finished in September 2006, it operated stably until the end of data taking at HERA end of June 2007. The present paper gives a brief overview of the physics processes of interest and the general detector design. The recoil detector components, their calibration, the momentum reconstruction of charged particles, and the event selection are described in detail. The paper closes with a summary of the performance of the detection system.

The HERMES recoil detector

Energy Technology Data Exchange (ETDEWEB)

Airapetian, A. [Giessen Univ. (Germany). Physikalisches Inst.; Michigan Univ., Ann Arbor, MI (United States). Randall Laboratory of Physics; Aschenauer, E.C. [DESY, Zeuthen (Germany); Belostotski, S. [B.P. Konstantinov Petersburg Nuclear Physics Insitute, Gatchina (Russian Federation)] [and others; Collaboration: HERMES Recoil Detector Group

2013-02-15

For the final running period of HERA, a recoil detector was installed at the HERMES experiment to improve measurements of hard exclusive processes in charged-lepton nucleon scattering. Here, deeply virtual Compton scattering is of particular interest as this process provides constraints on generalised parton distributions that give access to the total angular momenta of quarks within the nucleon. The HERMES recoil detector was designed to improve the selection of exclusive events by a direct measurement of the four-momentum of the recoiling particle. It consisted of three components: two layers of double-sided silicon strip sensors inside the HERA beam vacuum, a two-barrel scintillating fibre tracker, and a photon detector. All sub-detectors were located inside a solenoidal magnetic field with an integrated field strength of 1Tm. The recoil detector was installed in late 2005. After the commissioning of all components was finished in September 2006, it operated stably until the end of data taking at HERA end of June 2007. The present paper gives a brief overview of the physics processes of interest and the general detector design. The recoil detector components, their calibration, the momentum reconstruction of charged particles, and the event selection are described in detail. The paper closes with a summary of the performance of the detection system.

Needle counter

International Nuclear Information System (INIS)

Fujita, Yuzo

1977-01-01

Needle counter had been devised by Geiger about 60 years ago before the present GM counter appeared. It is suitable for the detection of weak radiation because it is limited in effective volume, if the background due to mainly cosmic ray is proportional to the effective volume of the counter. Recently the very low β detector having a needle counter as the main detector has been developed. It showed highly excellent performance in the measurements of small area samples, about ten times sensitive as compared with other detectors. The counter is installed in the very low radiation measuring well at Nokogiriyama, Chiba Prefecture, using a NaI scintillator as its guard counter. D. H. Wilkinson first treated a gas amplification counter theoretically and quantitatively. The authors have obtained good results in the comparison with the experiments of the counter using a generalized form of Wilkinson theory. The findings obtained through this study seem to be applicable to the electrode arrangement which is important for the counter design. It was found that the excellent rise time of induced pulses in a gas amplification counter was achieved in larger amplification factor and smaller convolution effect. In the detection of charged particles with small obstructing capability such as γ ray, faster rise time and higher pulses can be obtained with needle counters than wire counters. (Wakatsuki, Y.)

Preliminary results from a high-pressure imaging spectroscopic proportional counter

International Nuclear Information System (INIS)

Hall, C.J.; Bazzano, A.; Lewis, R.A.; Parker, B.; Ubertini, P.; Worgan, J.S.

1992-01-01

A new type of high-pressure proportional counter, with both spatial resolution and spectroscopic capabilities is being jointly developed by the Istituto di Astrofisica Spaziale (CNR), Frascati, Italy and the SERC Daresbury Laboratory, Warrington, UK. The characteristics of the detector can be optimized for the particular requirement of the experiment, either for x-ray astronomy observations from space, or for the high count rate applications associated with a synchrotron light source. In its baseline configuration, the detector is filled to 5 bar with a xenon/quench gas mixture and will be sensitive over the energy range 5 keV to 150 keV (2.5 to 0.08 A). The positional resolution will range from 500 μm at the lower energies to around 1 mm at the higher end of the energy range. The current prototype has a sensitive area of 200x200 mm. The final version is hoped to have an area closer to 425x425 mm. The very small photon absorption length in the higher pressure gas allows the parallax effect, a feature of 1 atmosphere detectors, to be greatly reduced. The timing resolution (150 ns) of the detector enables both a high-rate capability and the possibility of the escape gate technique to achieve higher spectral resolution at energies > the Xe K edge. Preliminary results are presented showing the spectral and positional resolution for the prototype detector

Cage effect in recoil studies

International Nuclear Information System (INIS)

Berei, K.

1983-09-01

The role of cage effect is one of the most discussed questions of hot atom chemistry in condensed organic systems. So far no direct evidence is available for assessing the exact contribution of thermal recombinations occurring in the liquid cage to the stabilization processes of recoil atoms. However, some conclusions can be drawn from experimental observations concerning the influence on product yield of hot atom recoil spectra, the effects of density, phase and long range order of the medium as well as from comparisons with systems providing cage walls of different chemical reactivities towards the recoil atom. Recent developments in this field are reviewed based primarily on the investigations of recoil halogen reactions in aliphatic and aromatic hydrocarbons and their haloderivatives. (author)

ZZ RECOIL/B, Heavy Charged Particle Recoil Spectra Library for Radiation Damage Calculation

International Nuclear Information System (INIS)

Gabriel, T.A.; Amburgey, J.D.; Greene, N.M.

1983-01-01

1 - Description of problem or function: Format: GAM-II group structure; Number of groups: 104 neutron and Recoil-energy groups; Nuclides: Elements Included in Charged-Particle Recoil Data Base: Al, W, Ti, Pb, V, Mg, Cr, Be, Mn, C, Fe, Au, Co, Si, Ni, B-10, Cu, B-11, Zr, N, Nb, Li-6, Mo, Li-7, Ta (Data for Ta-181,Ta-182), O, Origin: ENDF/B-IV cross-section data. A heavy charged-particle recoil data base (primary knock-on atom (PKA) spectra) and an analysis program have been created to assist experimentalists in studying, evaluating, and correlating radiation-damage effects in different neutron environments. Since experimentally obtained controlled thermo-nuclear-reactor-type neutron spectra are not presently available, the data base can be extremely useful in relating currently obtainable radiation damage to that which is anticipated in future fusion devices. However, the usefulness of the data base is not restricted to just CTR needs. Most of the elements of interest to the radiation-damage community and all neutron reactions of any significance for these elements have been processed, using available ENDF/B-IV cross-section data, and are included in the data base. Calculated data such as primary recoil spectra, displacement rates, and gas-production rates, obtained with the data base, for different radiation environments are presented and compared with previous calculations. Primary neutrons with energies up to 20 MeV have been considered. The elements included in the data base are listed in Table I. All neutron reactions of significance for these elements (i.e., elastic, inelastic, (n,2n), (n,3n), (n,p), (n,sigma), (n,gamma), etc.,) which have cross sections available from ENDF/B-IV have been processed and placed in the data base. Table I - Elements Included in Charged-Particle Recoil Data Base: Al, W, Ti, Pb, V, Mg, Cr, Be, Mn, C, Fe, Au, Co, Si, Ni, 10 B, Cu, 11 B, Zr, N, Nb, 6 Li, Mo, 7 Li, Ta (Data for Ta 181 ,Ta 182 ), O. 2 - Method of solution: The neutron

Light yield as a function of gas pressure and electric field in gas scintillation proportional counters

International Nuclear Information System (INIS)

Favata, F.; Smith, A.; Bavdaz, M.; Kowalski, T.Z.

1990-01-01

We have investigated the dependence of the scintillation light output for Xe on gas pressure in the range 0.14-1.4 bar, using a gas scintillation proportional counter, in different experimental configurations. We have compared our work with that of previous workers, and have shown that both our results and the results of previous authors are compatible with the intrinsic light output being independent of gas pressure, with any observed dependence being a pure experimental effect due to the spectral response of the various UV detectors used. We also use our experimental data for determining the ratio between the cross section of the Xe 2 ** +Xe→Xe 2 * +Xe reaction and the rate of the Xe 2 ** →2Xe+γ UV reaction. (orig.)

Radiation effects on the proportional counter X-ray detectors on board the NEAR spacecraft

International Nuclear Information System (INIS)

Floyd, S.R.; Trombka, J.I.; Leidecker, H.W.; Clark, P.E.; Starr, R.; Goldsten, J.O.; Roth, D.R.

1999-01-01

The X-ray proportional counters on board the Near Earth Asteroid Rendezvous (NEAR) spacecraft have exhibited a resolution degradation and recovery phenomenon several times during the long cruise phase of the mission. The resolution is checked periodically by commanding an 55 Fe source into the window area. The degradation is seen as a low energy tailing of the 5.9 keV photopeak. Two events have occurred which provided good spectral data for better understanding the degradation phenomenon. In November 1997 a large solar particle event occurred that degraded the resolution and excited copper in the collimator. Eventually the detectors returned to normal. In January 1998 the spacecraft performed an Earth swingby gravity assist maneuver. The near Earth environment excited the magnesium and aluminum in the filter elements. The copper line was also produced. The NEAR spacecraft was launched in February 1996 and will rendezvous and orbit the asteroid 433 Eros in early 1999

Absolute measurement and international intercomparison of 0.1-0.8 MeV monoenergetic neutron fluence rate

International Nuclear Information System (INIS)

Ma Hongchang; Lu Hanlin; Rong Chaofan

1988-01-01

The methods for absolute measurement of 0.1-18MeV monoenergetic neutron fluence rate are described. Which include proton recoil telescope, semicoducetor telescope, hydrogen filled proportional counter and associated particale method. A long counter used as secondary recent international intercomparison of neutron fluence rate organized by BIPM, and the results were given

D0-brane recoil revisited

Energy Technology Data Exchange (ETDEWEB)

Craps, Ben [Theoretische Natuurkunde, Vrije Universiteit Brussel and The International Solvay Institutes, Pleinlaan 2, B-1050 Brussels (Belgium); Evnin, Oleg [California Institute of Technology 452-48, Pasadena, CA 91125 (United States); Nakamura, Shin [Physics Department, Hanyang University, Seoul, 133-791 (Korea, Republic of)

2006-12-15

One-loop string scattering amplitudes computed using the standard D0-brane conformal field theory (CFT) suffer from infrared divergences associated with recoil. A systematic framework to take recoil into account is the worldline formalism, where fixed boundary conditions are replaced by dynamical D0-brane worldlines. We show that, in the worldline formalism, the divergences that plague the CFT are automatically cancelled in a non-trivial way. The amplitudes derived in the worldline formalism can be reproduced by deforming the CFT with a specific 'recoil operator', which is bilocal and different from the ones previously suggested in the literature.

Development of extruded resistive plastic tubes for proportional chamber cathodes

International Nuclear Information System (INIS)

Kondo, K.

1982-01-01

Carbon mixed plastic tubes with resistivity of 10 3 approx. 10 4 Ωcm have been molded with an extrusion method and used for the d.c. cathode of a proportional counter and a multi-wire proportional chamber. The signal by gas multiplication was picked up from a strip r.f. cathode set outside the tube. The characteristics of the counter in the proportional and limited streamer modes have been studied

A primary scintillation gated high pressure position sensitive gas scintillation proportional counter (HPGSPC) for applications to x-ray astronomy

International Nuclear Information System (INIS)

Giarrusso, S.; Manzo, G.; Re, S.

1985-01-01

The authors describe a new instrument for x-ray astronomy. The instrument, based on a high pressure (5 atm.), xenon filled, position sensitive Gas Scintillation Proportional counter (HPGSPC) is expected to feature an energy resolution better than 4% at 60 keV, an angular resolution of approximately 20 arc-minutes over the full energy range (4 to 100 keV) and a field of view (FOV) of up to 30x30 degrees. A prototype flight unit of the gas cell on which the instrument is based is presently under technological development in the framework of the SAX project

Interpreting Recoil for Undergraduate Students

Science.gov (United States)

Elsayed, Tarek A.

2012-01-01

The phenomenon of recoil is usually explained to students in the context of Newton's third law. Typically, when a projectile is fired, the recoil of the launch mechanism is interpreted as a reaction to the ejection of the smaller projectile. The same phenomenon is also interpreted in the context of the conservation of linear momentum, which is…

Broad Energy Range Neutron Spectroscopy using a Liquid Scintillator and a Proportional Counter: Application to a Neutron Spectrum Similar to that from an Improvised Nuclear Device.

Science.gov (United States)

Xu, Yanping; Randers-Pehrson, Gerhard; Marino, Stephen A; Garty, Guy; Harken, Andrew; Brenner, David J

2015-09-11

A novel neutron irradiation facility at the Radiological Research Accelerator Facility (RARAF) has been developed to mimic the neutron radiation from an Improvised Nuclear Device (IND) at relevant distances (e.g. 1.5 km) from the epicenter. The neutron spectrum of this IND-like neutron irradiator was designed according to estimations of the Hiroshima neutron spectrum at 1.5 km. It is significantly different from a standard reactor fission spectrum, because the spectrum changes as the neutrons are transported through air, and it is dominated by neutron energies from 100 keV up to 9 MeV. To verify such wide energy range neutron spectrum, detailed here is the development of a combined spectroscopy system. Both a liquid scintillator detector and a gas proportional counter were used for the recoil spectra measurements, with the individual response functions estimated from a series of Monte Carlo simulations. These normalized individual response functions were formed into a single response matrix for the unfolding process. Several accelerator-based quasi-monoenergetic neutron source spectra were measured and unfolded to test this spectroscopy system. These reference neutrons were produced from two reactions: T(p,n) 3 He and D(d,n) 3 He, generating neutron energies in the range between 0.2 and 8 MeV. The unfolded quasi-monoenergetic neutron spectra indicated that the detection system can provide good neutron spectroscopy results in this energy range. A broad-energy neutron spectrum from the 9 Be(d,n) reaction using a 5 MeV deuteron beam, measured at 60 degrees to the incident beam was measured and unfolded with the evaluated response matrix. The unfolded broad neutron spectrum is comparable with published time-of-flight results. Finally, the pair of detectors were used to measure the neutron spectrum generated at the RARAF IND-like neutron facility and a comparison is made to the neutron spectrum of Hiroshima.

Photon and neutron dose discrimination using low pressure proportional counters with graphite and A150 walls

International Nuclear Information System (INIS)

Kylloenen, J.; Lindborg, L.

2005-01-01

Full text: The determination of both the low- and high-LET components of ambient dose equivalent in mixed fields is possible with microdosimetric methods. With the multiple-event microdosimetric variance covariance method the sum of those components are directly obtained also in pulsed beams. However, if the value of each dose component is needed a more extended analysis is required. The use of a graphite walled proportional detector in combination with a tissue-equivalent proportional counter in combination with the variance covariance method was here investigated. MCNP simulations were carried out for relevant energies to investigate the photon and neutron responses of the two detectors. The combined graphite and TEPC system, the Sievert instrument, was used for measurements at IRSN, Cadarache, in the workplace calibration fields of CANEL+, SIGMA, a Cf-252 and a moderated Cf(D 2 O,Cd) radiation field. The response of the instrument in various monoenergetic neutron fields is also known from measurements at PTB. The instrument took part in the measurement campaigns in workplace fields in the nuclear industry organized within the EVIDOS contract. The results are analyzed and the method of using a graphite detector compared with alternative methods of analysis is discussed. (author)

Detection of pulsed fast neutrons by a proportional counter boron-convered and enveloped in paraffin moderators

International Nuclear Information System (INIS)

Goncalez, O.L.; Yanagihara, L.S.; Veissid, V.L.C.P.; Herdade, S.B.

1983-01-01

The response to pulsed fast neutrons by a parafin moderated boron-lined proportional counter is investigated theoretically and experimentally. The neutrons pulses are generated by 60 MeV electrons from a linear accelerator. The calculation of the counting loss based on the detector dead time and on the exponential decresse of the thermal neutron population in the moderator is presented in detail. An analytical relation between the true counting rate and the reduced one, indicated by the detector, is found. In this formula three parameters appear: the decay constant of the thermal neutron population, the detector dead time and the pulse frequency of the neutron source. The decay constant is calculated by diffusion theory. The experimental results for six values of moderator thickness (between 2.5 to 12.5 cm) agree with our theoretical calculation within 20 per cent. (Author) [pt

Background simulation for the Spherical Proportional Counter and its use for the detection of optical photons

International Nuclear Information System (INIS)

Bougamont, E; Colas, P; Dastgheibi-Fard, A; Derre, J; Giomataris, I; Gerbier, G; Gros, M; Magnier, P; Navick, X F; Tsiledakis, G; Salin, P; Savvidis, I; Vergados, J D

2013-01-01

The recently developed Spherical Proportional Counter [1] allows to instrument large target masses with good energy resolution and sub-keV energy threshold. The moderate cost of this detector, its simplicity and robustness, makes this technology a promising approach for many domains of physics and applications, like dark matter detection and low energy neutrino searches. Detailed Monte Carlo simulations are essential to evaluate the background level expected at the sub-keV energy regime. The simulated background here, it refers to the contribution of the construction material of the detector and the effect of the environmental gamma radiation. This detector due to its spherical shape could be also served as an optical photon detector provided it is equipped with PMTs, for Double Beta decay and Dark Matter searches. All calculations shown here are obtained using the FLUKA Monte Carlo code

Calibration of the Large Area X-Ray Proportional Counter (LAXPC) Instrument on board AstroSat

Energy Technology Data Exchange (ETDEWEB)

Antia, H. M.; Yadav, J. S.; Chauhan, Jai Verdhan; Chitnis, Varsha; Dedhia, Dhiraj; Shah, Parag; Gujar, V. M.; Katoch, Tilak; Kurhade, V. N.; Madhwani, Pankaj; Manojkumar, T. K.; Nikam, V. A.; Pandya, A. S.; Parmar, J. V.; Pawar, D. M. [Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005 (India); Agrawal, P. C. [UM-DAE Centre of Excellence for Basic Sciences, University of Mumbai, Kalina, Mumbai 400098 (India); Manchanda, R. K. [University of Mumbai, Kalina, Mumbai 400098 (India); Paul, Biswajit [Department of Astronomy and Astrophysics, Raman Research Institute, Bengaluru 560080 (India); Pahari, Mayukh; Misra, Ranjeev [Inter-University Centre for Astronomy and Astrophysics, Pune 411007 (India); and others

2017-07-01

We present the calibration and background model for the Large Area X-ray Proportional Counter (LAXPC) detectors on board AstroSat . The LAXPC instrument has three nominally identical detectors to achieve a large collecting area. These detectors are independent of each other, and in the event analysis mode they record the arrival time and energy of each photon that is detected. The detectors have a time resolution of 10 μ s and a dead-time of about 42 μ s. This makes LAXPC ideal for timing studies. The energy resolution and peak channel-to-energy mapping were obtained from calibration on the ground using radioactive sources coupled with GEANT4 simulations of the detectors. The response matrix was further refined from observations of the Crab after launch. At around 20 keV the energy resolution of the detectors is 10%–15%, while the combined effective area of the three detectors is about 6000 cm{sup 2}.

PEP quark search proportional chambers

Energy Technology Data Exchange (ETDEWEB)

Parker, S I; Harris, F; Karliner, I; Yount, D [Hawaii Univ., Honolulu (USA); Ely, R; Hamilton, R; Pun, T [California Univ., Berkeley (USA). Lawrence Berkeley Lab.; Guryn, W; Miller, D; Fries, R [Northwestern Univ., Evanston, IL (USA)

1981-04-01

Proportional chambers are used in the PEP Free Quark Search to identify and remove possible background sources such as particles traversing the edges of counters, to permit geometric corrections to the dE/dx and TOF information from the scintillator and Cerenkov counters, and to look for possible high cross section quarks. The present beam pipe has a thickness of 0.007 interaction lengths (lambdasub(i)) and is followed in both arms each with 45/sup 0/ <= theta <= 135/sup 0/, ..delta..phi=90/sup 0/ by 5 proportional chambers, each 0.0008 lambdasub(i) thick with 32 channels of pulse height readout, and by 3 thin scintillator planes, each 0.003 lambdasub(i) thick. Following this thin front end, each arm of the detector has 8 layers of scintillator (one with scintillating light pipes) interspersed with 4 proportional chambers and a layer of lucite Cerenkov counters. Both the calculated ion statistics and measurements using He-CH/sub 4/ gas in a test chamber indicate that the chamber efficiencies should be >98% for q=1/3. The Landau spread measured in the test was equal to that observed for normal q=1 traversals. One scintillator plane and thin chamber in each arm will have an extra set of ADC's with a wide gate bracketing the normal one so timing errors and tails of earlier pulses should not produce fake quarks.

Recoil mixing in high-fluence ion implantation

International Nuclear Information System (INIS)

Littmark, U.; Hofer, W.O.

1979-01-01

The effect of recoil mixing on the collection and depth distribution of implanted projectiles during high-fluence irradiation of a random solid is investigated by model calculations based on a previously published transport theoretical approach to the general problem of recoil mixing. The most pronounced effects are observed in the maximum implantable amount of projectiles and in the critical fluence for saturation. Both values are significantly increased by recoil mixing. (Auth.)

A comparison between the measurements of Kr-85 in environmental samples by liquid scintillation and proportional counters; Comparacion de resultados de la medida radiactiva del Kr-85 ambiental por centelleo liquido y contadores proporcionales

Energy Technology Data Exchange (ETDEWEB)

Heras, M. C.; Perez, M. M.

1983-07-01

The most used methods for the measurement of Kr-81 beta-activity after their concentration and aisolation are the liquid scintillation counting and the proportional counter. In this work the beta activity of concentrated and aisolated Kr-85 samples measured in collaboration with the Max-Planck Institut fur Kernphyslk, Aussenstelle Freiburg. Samples taken both In Madrid and Frelburg are measured by proportional counters in the Max-Planck lnstitut, Freibury and by liquid scintillation counting in JEN, Madrid. The comparison of both measurements do not show appreciable discrepancy between the results obtained to both techniques. (Author)

Complementary scattered and recoiled ion data from TOF-E heavy ion elastic recoil detection analysis

International Nuclear Information System (INIS)

Johnston, P.N.; El Bouanani, M.; Stannard, W.B.; Bubb, I.F.; Cohen, D.D.; Dytlewski, N.; Siegele, R.

1998-01-01

The advantage of Time of Flight and Energy (ToF-E) Heavy Ion Elastic Recoil Detection Analysis (HIERDA) over Rutherford Backscattering (RBS) analysis is its mass and energy dispersive capabilities. The mass resolution of ToF-E HIERDA deteriorates for very heavy elements. The limitation is related to the poor energy resolution of Si detectors for heavy ions. While the energy spectra from ToF-E HIERDA data are normally used to extract depth profiles, this work discusses the benefits of using the time spectra of both the recoiled and the scattered ions for depth profiling. The simulation of the complementary scattered and recoiled ion time spectra improves depth profiling and reduced current limitations when dealing with very heavy ions, such as Pt, Bi, Ta. (authors)

Scintillation efficiency of nuclear recoil in liquid xenon

CERN Document Server

Arneodo, F; Badertscher, A; Benetti, P; Bernardini, E; Bettini, A; Borio di Tigliole, A A; Brunetti, R; Bueno, A G; Calligarich, E; Campanelli, M; Carpanese, C; Cavalli, D; Cavanna, F; Cennini, P; Centro, Sandro; Cesana, A; Cline, D; De Mitri, I; Dolfini, R; Ferrari, A; Gigli-Berzolari, A; Matthey, C; Mauri, F; Mazza, D; Mazzone, L; Meng, G; Montanari, C; Nurzia, G; Otwinowski, S; Palamara, O; Pascoli, D; Pepato, Adriano; Petrera, S; Periale, L; Piano Mortari, G; Piazzoli, A; Picchi, P; Pietropaolo, F; Rancati, T; Rappoldi, A; Raselli, G L; Rebuzzi, D; Revol, Jean Pierre Charles; Rico, J; Rossella, M; Rossi, C; Rubbia, André; Rubbia, Carlo; Sala, P; Scannicchio, D A; Sergiampietri, F; Suzuki, S; Terrani, M; Tian, W; Ventura, Sandro; Vignoli, C; Wang, H; Woo, J; Xu, Z

2000-01-01

We present the results of a test done with a Liquid Xenon (LXe) detector for 'Dark Matter' search, exposed to a neutron beam to produce nuclear recoil events simulating those which would be generated by WIMP's elastic scattering. The aim of the experiment was to measure directly the scintillation efficiency of nuclear recoil. The nuclear recoil considered in the test was in the tens of keV range. The ratio of measured visible energy over the true recoil energy was evaluated to be about 20%, in good agreement with the theoretical predictions.

90Sr- 90Y and 89Sr beta radioactivity measurement in milk samples using a proportional counter

International Nuclear Information System (INIS)

Mananes, A.; Perez Santos, C.; Martinez Churiaque, F.

1987-01-01

A thin window glas flow proportional counter is used to measure the 90 Sr- 90 Y and 89 Sr beta radioactivity in milk samples. A chemical procedure is used to separate strontium-yttrium from the other radionuclides present in milk. A calculation of the total efficiency of the system is performed which includes an empirical estimation of the backscattering factor. The calibration of the whole process allows the determination of the 90 Sr activity within 10% relative error in spite of uncertainties in the recovery yields of strontium and yttrium. No 89 Sr activity has been detected, and the mean value obtained for the 90 Sr activity in nine milk samples of Cantabria is 0.115 Bq/1 with a minimum detectable activity of 0.0105 Bq. (author) 18 refs

Ionization and scintillation of nuclear recoils in gaseous xenon

Energy Technology Data Exchange (ETDEWEB)

Renner, J., E-mail: jrenner@lbl.gov [Lawrence Berkeley National Laboratory (LBNL), 1 Cyclotron Road, Berkeley, CA 94720 (United States); Department of Physics, University of California, Berkeley, CA 94720 (United States); Gehman, V.M.; Goldschmidt, A.; Matis, H.S.; Miller, T.; Nakajima, Y.; Nygren, D.; Oliveira, C.A.B.; Shuman, D. [Lawrence Berkeley National Laboratory (LBNL), 1 Cyclotron Road, Berkeley, CA 94720 (United States); Álvarez, V. [Instituto de Física Corpuscular (IFIC), CSIC & Universitat de València, Calle Catedrático José Beltrán, 2, 46980 Paterna, Valencia (Spain); Borges, F.I.G. [Departamento de Fisica, Universidade de Coimbra, Rua Larga, 3004-516 Coimbra (Portugal); Cárcel, S. [Instituto de Física Corpuscular (IFIC), CSIC & Universitat de València, Calle Catedrático José Beltrán, 2, 46980 Paterna, Valencia (Spain); Castel, J.; Cebrián, S. [Laboratorio de Física Nuclear y Astropartículas, Universidad de Zaragoza, Calle Pedro Cerbuna 12, 50009 Zaragoza (Spain); Cervera, A. [Instituto de Física Corpuscular (IFIC), CSIC & Universitat de València, Calle Catedrático José Beltrán, 2, 46980 Paterna, Valencia (Spain); Conde, C.A.N. [Departamento de Fisica, Universidade de Coimbra, Rua Larga, 3004-516 Coimbra (Portugal); and others

2015-09-01

Ionization and scintillation produced by nuclear recoils in gaseous xenon at approximately 14 bar have been simultaneously observed in an electroluminescent time projection chamber. Neutrons from radioisotope α-Be neutron sources were used to induce xenon nuclear recoils, and the observed recoil spectra were compared to a detailed Monte Carlo employing estimated ionization and scintillation yields for nuclear recoils. The ability to discriminate between electronic and nuclear recoils using the ratio of ionization to primary scintillation is demonstrated. These results encourage further investigation on the use of xenon in the gas phase as a detector medium in dark matter direct detection experiments.

Optimizing Higgs factories by modifying the recoil mass

Energy Technology Data Exchange (ETDEWEB)

Gu, Jiayin [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Chinese Academy of Sciences, Beijing (China). Center for Future High Energy Physics; Li, Ying-Ying [Hong Kong Univ. of Science and Technology, Kowloon (China). Dept. of Physics

2017-10-15

It is difficult to measure the WW-fusion Higgs production process (e{sup +}e{sup -}→ν anti νh) at a lepton collider with a center of mass energy of 240-250 GeV due to its small rate and the large background from the Higgsstrahlung process with an invisible Z (e{sup +}e{sup -}→hZ, Z→ν anti ν). We construct a modified recoil mass variable, m{sup p}{sub recoil}, defined using only the 3-momentum of the reconstructed Higgs particle, and show that it can better separate the WW-fusion and Higgsstrahlung events than the original recoil mass variable m{sub recoil}. Consequently, the m{sup p}{sub recoil} variable can be used to improve the overall precisions of the extracted Higgs couplings, in both the conventional framework and the effective-field-theory framework. We also explore the application of the m{sup p}{sub recoil} variable in the inclusive cross section measurements of the Higgsstrahlung process, while a quantitive analysis is left for future studies.

100 group displacement cross sections from RECOIL data base

International Nuclear Information System (INIS)

Gopalakrishnan, V.

1995-01-01

Displacement cross sections in 100 neutron energy groups were calculated from the RECOIL data base using the RECOIL program, for use in DPA (Displacement Per Atom) calculations for FBTR and PFBR materials. 100 group displacement cross sections were calculated using RECOIL-Data Base and RECOIL Program. Modifications were made in the data base to reduce space requirement, and in the program for easy handling on a PC. 2 refs

Chemical effects of fission recoils

International Nuclear Information System (INIS)

Meisels, G.G.; Freeman, J.P.; Gregory, J.P.; Richardson, W.C.; Sroka, G.J.

1978-01-01

The production of nitrogen from nitrous oxide at high density was employed to investigate the energy deposition efficiency of fission recoils produced from fission of U 235 in uranium-palladium foils clad with platinum. Nitrogen production varied linearly with fission recoil dose from 1.1 x 10 20 to 9.0 x 10 20 eV, and was independent of density between 12.5 and 127.5 g l -1 N 2 O. 16.2 +- 0.8% of the fission recoil energy was deposited external to the foil. Electron microprobe analysis showed some unevenness of new foil and polymer buildup on the surface after irradiation of ethylene-oxygen mixtures. Subsequent irradiation in the presence of nitrous oxide restored some of the original efficiency. This is ascribed to chemical oxidation of the polymer induced by reactive intermediates produced from nitrous oxide. (author)

Development of NRESP98 Monte Carlo codes for the calculation of neutron response functions of neutron detectors. Calculation of the response function of spherical BF{sub 3} proportional counter

Energy Technology Data Exchange (ETDEWEB)

Hashimoto, M.; Saito, K.; Ando, H. [Power Reactor and Nuclear Fuel Development Corp., Oarai, Ibaraki (Japan). Oarai Engineering Center

1998-05-01

The method to calculate the response function of spherical BF{sub 3} proportional counter, which is commonly used as neutron dose rate meter and neutron spectrometer with multi moderator system, is developed. As the calculation code for evaluating the response function, the existing code series NRESP, the Monte Carlo code for the calculation of response function of neutron detectors, is selected. However, the application scope of the existing NRESP is restricted, the NRESP98 is tuned as generally applicable code, with expansion of the geometrical condition, the applicable element, etc. The NRESP98 is tested with the response function of the spherical BF{sub 3} proportional counter. Including the effect of the distribution of amplification factor, the detailed evaluation of the charged particle transportation and the effect of the statistical distribution, the result of NRESP98 calculation fit the experience within {+-}10%. (author)

Evaluation of B10Plus+* proportional detectors for neutron coincidence counting

Energy Technology Data Exchange (ETDEWEB)

Beddingfield, David H.; Yoon, Seokryung [International Atomic Energy Agency, Vienna International Centre, PO Box 100, 1400 Vienna, (Austria)

2015-07-01

GE-Reuter-Stokes (GERS) has developed a new line of neutron proportional counters, the B10Plus+* proportional counter. The detector design is intended to serve as a cost-effective alternative to traditional {sup 3}He proportional counters in a variety of applications. The detector is a hybrid design 10B-lined tube optimized with the addition of a small quantity of 3He gas to improve the detector performance and efficiency. As a demonstration of the B10Plus+* detector, GERS has constructed a Uranium Neutron Collar (UNCL) system consisting of B-10Plus+* proportional counters. GERS has designed and built a demonstration UNCL system intended to match the performance of a Type-I UNCL design in Pressurized Water Reactor (PWR) geometry operating in thermal mode. GERS offered their system on loan to the International Atomic Energy Agency (IAEA) Safeguards Division of Technical and Scientific Services for an assessment of the detector technology and the demonstration system. We have characterized the demonstration UNCL system and compared its performance with a traditional Type-I UNCL design in regular use by the IAEA. This paper summarizes our findings and observations during the characterization and testing activity. (authors)

An investigation of the effect of some gaseous admixtures on the ionization currents in the air in the discharge chambers of the proportional counter type

International Nuclear Information System (INIS)

Berdowska, E.; Zastawny, A.

1981-01-01

Voltage-current characteristics of the ionization discharge in chambers of the proportional counter filled with air with admixtures of CO, CO 2 , CH 4 and H 2 O have been investigated. It was found that in the transition region between dependent and self-maintained discharge the characteristics change sufficiently for detection of the presence of those admixtures in the air. (author)

Hydrogen high pressure proportional drift detector

International Nuclear Information System (INIS)

Arefiev, A.; Balaev, A.

1983-01-01

The design and operation performances of a proportional drift detector PDD are described. High sensitivity of the applied PAD makes it possible to detect the neutron-proton elastic scattering in the energy range of recoil protons as low as 1 keV. The PDD is filled with hydrogen up to the pressure at 40 bars. High purity of the gas is maintained by a continuously operating purification system. The detector has been operating for several years in a neutron beam at the North Area of the CERN SPS

An Evaluation of Magneto Rheological Dampers for Controlling Gun Recoil Dynamics

Directory of Open Access Journals (Sweden)

Mehdi Ahmadian

2001-01-01

Full Text Available The application of magneto rheological dampers for controlling recoil dynamics is examined, using a recoil demonstrator that includes a single-shot 50 caliber BMG rifle action and a MR damper. The demonstrator is selected such that it can adequately represent the velocities that commonly occur in weapons with a recoil system, and can be used for collecting data for analyzing the effects of MR dampers on recoil dynamics. The MR damper is designed so that it can work effectively at the large velocities commonly occurring in gun recoil, and also be easily adjusted to reasonably optimize the damper performance for the recoil demonstrator. The test results show that it is indeed possible to design and use MR dampers for recoil applications, which subject the damper to relative velocities far larger than the applications that such dampers have commonly been used for (i.e., vehicle applications. Further, the results indicate that the recoil force increases and the recoil stroke decreases nonlinearly with an increase in the damping force. Also of significance is the fact that the adjustability of MR dampers can be used in a closed-loop system such that the large recoil forces that commonly occur upon firing the gun are avoided and, simultaneously, the recoil stroke is reduced. This study points to the need for several areas of research including establishing the performance capabilities for MR dampers for gun recoil applications in an exact manner, and the potential use of such dampers for a fire out of battery recoil system.

Gas powered fluid gun with recoil mitigation

Science.gov (United States)

Grubelich, Mark C; Yonas, Gerold

2013-11-12

A gas powered fluid gun for propelling a stream or slug of a fluid at high velocity toward a target. Recoil mitigation is provided that reduces or eliminates the associated recoil forces, with minimal or no backwash. By launching a quantity of water in the opposite direction, net momentum forces are reduced or eliminated. Examples of recoil mitigation devices include a cone for making a conical fluid sheet, a device forming multiple impinging streams of fluid, a cavitating venturi, one or more spinning vanes, or an annular tangential entry/exit.

Direct determination of recoil ion detection efficiency for coincidence time-of-flight studies of molecular fragmentation

International Nuclear Information System (INIS)

Ben-Itzhak, I.; Carnes, K.D.; Ginther, S.G.; Johnson, D.T.; Norris, P.J.; Weaver, O.L.

1993-01-01

Molecular fragmentation of diatomic and small polyatomic molecules caused by fast ion impact has been studied. The evaluation of the cross sections of the different fragmentation channels depends strongly on the recoil ion detection efficiency, ε r (single ions proportional to ε r , and ion pairs to ε 2 r , etc.). A method is suggested for the direct determination of this detection efficiency. This method is based on the fact that fast H + + CH 4 collisions produce C 2+ fragments only in coincidence with H + and H + 2 fragments, that is, there is a negligible number of C 2+ singles, if any. The measured yield of C 2+ singles is therefore due to events in which the H + m of the H + m + C 2+ ion pair was not detected and thus is proportional to 1 - ε r . Methane fragmentation caused by 1 MeV proton impact is used to evaluate directly the recoil ion detection efficiency and to demonstrate the method of deriving the cross sections of all breakup channels. (orig.)

Calibration of a low background gas-flow proportional counter to estimate "2"3"4Th activity in coastal waters

International Nuclear Information System (INIS)

Cuesta, E.; Lozano, R.L.; Miguel, E.G. San; Casas-Ruiz, M.; Bolívar, J.P.

2016-01-01

This paper relates the calibration of a low background gas-flow proportional counter. This calibration has been used to determine low activity of "2"3"4Th in coastal water samples. Two methods were used to prepare calibration samples: Evaporation and Electrodeposition. First method was rejected due to the lack of reproducibility because the different geometry adopted by the drops of tracer once dried on the disk. On the contrary, through the second method, similar efficiencies were obtained in all detectors with an average of 0.401±0.004. In this paper, the whole procedure to obtain "2"3"4Th activity in dissolution as well as in particulate matter has been detailed, and all the algorithms needed to calculate activities and efficiencies are shown. Finally, two experiments have been designed in order to validate the calibration of the beta counter and the method to determine "2"3"4Th in coastal waters with high concentration of particulate matter. - Highlights: • This paper shows a Home-made calibration using two methods to prepare calibration samples. • The algorithms needed to obtain Th-234 activity concentrations are described in full detail. • This is the first time Th-234 has been determined in water samples from Huelva Estuary.

The study of the influence of helium on the counter's measurement properties

International Nuclear Information System (INIS)

Guan Rui; Weng Kuiping; Ren Xingbi

2009-04-01

In measurement of tritium by the proportional counter, methane is usually used as counter gas. Gas samples have been made with helium and methane in the proportion of concentration and measured to study the influence of helium on the counter's measurement properties. Then gas sample with tritium and helium has been measured, and the result is according with anticipation. The experiment has showed that the plateau curve of counter could be changed by helium, but the influence could be ignored when helium concentration less 10%. (authors)

Optimizing Higgs factories by modifying the recoil mass

Science.gov (United States)

Gu, Jiayin; Li, Ying-Ying

2018-02-01

It is difficult to measure the WW-fusion Higgs production process ({{{e}}}+{{{e}}}-\\to {{ν }}\\bar{{{ν }}}{{h}}) at a lepton collider with a center of mass energy of 240-250 GeV due to its small rate and the large background from the Higgsstrahlung process with an invisible Z ({{{e}}}+{{{e}}}-\\to {{hZ}},{{Z}}\\to {{ν }}\\bar{{{ν }}}). We construct a modified recoil mass variable, {m}{{recoil}}p, defined using only the 3-momentum of the reconstructed Higgs particle, and show that it can separate the WW-fusion and Higgsstrahlung events better than the original recoil mass variable m recoil. Consequently, the {m}{{recoil}}p variable can be used to improve the overall precisions of the extracted Higgs couplings, in both the conventional framework and the effective-field-theory framework. We also explore the application of the {m}{{recoil}}p variable in the inclusive cross section measurements of the Higgsstrahlung process, while a quantitive analysis is left for future studies. JG is Supported by an International Postdoctoral Exchange Fellowship Program between the Office of the National Administrative Committee of Postdoctoral Researchers of China (ONACPR) and DESY. YYL is Supported by Hong Kong PhD Fellowship (HKPFS) and the Collaborative Research Fund (CRF) (HUKST4/CRF/13G)

Response of a carbon-walled proportional counter to 14 MeV neutrons

International Nuclear Information System (INIS)

Lewis, K.D.

1982-01-01

The response of a carbon-walled spherical proportional counter filled with a methane-based tissue-equivalent gas mixture at low pressure and irradiated with 14 MeV neutrons is first measured experimentally and is then calculated theoretically by using an analytical model. The model, called the CISS model, is derived from a consideration of four basic modes of interaction of charged particles generated in neutron-nucleus reactions with the spherical cavity of the detector. Since several quantities which have application in neutron dosimetry, radiation protection, and radiation biology make direct use of such spectra, it is desirable to have the ability to theoretically predict what is expected experimentally. Thus, a comparison between the two response curves is made. The discrepancy between them is investigated by considering several physical phenomena occurring within the detector wall which tend to distort the experimental response curve. In particular, the C(n,n',3α) reaction occurring in the detector wall gives rise to multiple events, originating from a single neutron interaction in the wall simultaneously strike the detector cavity, and are recorded as a single larger event in an experimental spectra. In the analytic model, the simultaneous entry of two charged particles into the cavity is scored as two separate smaller events, uncorrelated in their production. In this work, an effort is made to modify the analytic model prediction of the response curve by correcting for the multiple events which occur. Finally, the CISS model is used to compute mass stopping power corrections for this inhomogeneous detector

Optimal control of gun recoil in direct fire using magnetorheological absorbers

International Nuclear Information System (INIS)

Singh, Harinder J; Wereley, Norman M

2014-01-01

Optimal control of a gun recoil absorber is investigated for minimizing recoil loads and maximizing rate of fire. A multi-objective optimization problem was formulated by considering the mechanical model of the recoil absorber employing a spring and a magnetorheological (MR) damper. The damper forces are predicted by evaluating pressure drops using a nonlinear Bingham-plastic model. The optimization methodology provides multiple optimal design configurations with a trade-off between recoil load minimization and increased rate of fire. The configurations with low or high recoil loads imply low or high rate of fire, respectively. The gun recoil absorber performance is also analyzed for perturbations in the firing forces. The adaptive control of the MR damper for varying gun firing forces provides a smooth operation by returning the recoil mass to its battery position (ready to reload and fire) without incurring an end-stop impact. Furthermore, constant load transmissions are observed with respect to the recoil stroke by implementing optimal control during the simulated firing events. (paper)

Optimal control of gun recoil in direct fire using magnetorheological absorbers

Science.gov (United States)

Singh, Harinder J.; Wereley, Norman M.

2014-05-01

Optimal control of a gun recoil absorber is investigated for minimizing recoil loads and maximizing rate of fire. A multi-objective optimization problem was formulated by considering the mechanical model of the recoil absorber employing a spring and a magnetorheological (MR) damper. The damper forces are predicted by evaluating pressure drops using a nonlinear Bingham-plastic model. The optimization methodology provides multiple optimal design configurations with a trade-off between recoil load minimization and increased rate of fire. The configurations with low or high recoil loads imply low or high rate of fire, respectively. The gun recoil absorber performance is also analyzed for perturbations in the firing forces. The adaptive control of the MR damper for varying gun firing forces provides a smooth operation by returning the recoil mass to its battery position (ready to reload and fire) without incurring an end-stop impact. Furthermore, constant load transmissions are observed with respect to the recoil stroke by implementing optimal control during the simulated firing events.

Nuclear accident dosimetry: the calibration of Geiger-Mueller and 2π proportional counters for sulphur and gold

International Nuclear Information System (INIS)

Delafield, H.J.; Reading, A.H.

1981-10-01

A reference, 2π precision counter was set up at Harwell and absolutely calibrated for the measurement of sulphur discs ( 32 P) and gold foils ( 198 Au) used in the UK personnel criticality dosimeter. Sample sulphur discs and gold foils were irradiated in the GLEEP reactor at Harwell, counted in the 2π counter, and their activities absolutely assayed by the National Physical Laboratory. The 2π counter was then used to intercalibrate the GM counters used routinely for the assessment of the criticality dosimeter. The mean measured efficiencies of the GM counters were found to be for 32 P in sulphur discs within +- 4%, and for gold ( 198 Au) within +- 6% of the values given by previous calibrations. (author)

From the High Energy Physics Laboratory to the hospital -some experiences of the application of MWPC [multiwire proportional counter] technology to medicine

International Nuclear Information System (INIS)

Bateman, J.E.

1989-01-01

In this talk I wish to briefly review the experience we have obtained at the Rutherford Appleton Laboratory over the past decade in the adaptation of MWPC (multiwire proportional counter) technology to diagnostic imaging applications in medicine. A cursory glance at the history of science and technology quickly shows the often intimate and mutually beneficial relationship between ''pure'' science (and scientists) and practical applications. The following talk traces some of the principal features of the situation which have been brought to my attention in the course of the last decade. (author)

A Neutron Rem Counter

Energy Technology Data Exchange (ETDEWEB)

Andersson, I Oe; Braun, J

1964-01-15

A neutron detector is described which measures the neutron dose rate in rem/h independently of the energy of the neutrons from thermal to 15 MeV. The detector consists of a BF{sub 3} proportional counter surrounded by a shield made of polyethylene and boron plastic that gives the appropriate amount of moderation and absorption to the impinging neutrons to obtain rem response. Two different versions have been developed. One model can utilize standard BF{sub 3} counters and is suitable for use in installed monitors around reactors and accelerators and the other model is specially designed for use in a portable survey instrument. The neutron rem counter for portable instruments has a sensitivity of 2.4 cps/mrem/h and is essentially nondirectional in response. With correct bias setting the counter is insensitive to gamma exposure up to 200 r/h from Co-60.

A gun recoil system employing a magnetorheological fluid damper

International Nuclear Information System (INIS)

Li, Z C; Wang, J

2012-01-01

This research aims to design and control a full scale gun recoil buffering system which works under real firing impact loading conditions. A conventional gun recoil absorber is replaced with a controllable magnetorheological (MR) fluid damper. Through dynamic analysis of the gun recoil system, a theoretical model for optimal design and control of the MR fluid damper for impact loadings is derived. The optimal displacement, velocity and optimal design rules are obtained. By applying the optimal design theory to protect against impact loadings, an MR fluid damper for a full scale gun recoil system is designed and manufactured. An experimental study is carried out on a firing test rig which consists of a 30 mm caliber, multi-action automatic gun with an MR damper mounted to the fixed base through a sliding guide. Experimental buffering results under passive control and optimal control are obtained. By comparison, optimal control is better than passive control, because it produces smaller variation in the recoil force while achieving less displacement of the recoil body. The optimal control strategy presented in this paper is open-loop with no feedback system needed. This means that the control process is sensor-free. This is a great benefit for a buffering system under impact loading, especially for a gun recoil system which usually works in a harsh environment. (paper)

Origin of open recoil curves in L1_0-A1 FePt exchange coupled nanocomposite thin film

International Nuclear Information System (INIS)

Goyal, Rajan; Kapoor, Akanksha; Lamba, S.; Annapoorni, S.

2016-01-01

Mixed phase FePt systems with intergranular coupling may be looked upon as natural exchange spring systems. The coupling strength between the soft and hard phase in these systems can be analyzed using recoil curves. However, the origin of open recoil curves depicting the breakdown of exchange coupling or anisotropy variation in hard phase is still an ambiguity and requires an in-depth analysis. In order to investigate this, an analysis of the recoil curves for L1_0–A1 FePt nanocomposite thin films of varying thickness have been performed. The switching field distribution reveals that the maximum of openness of recoil curve is directly proportional to the amount of uncoupled soft phase present in the system. The coupling between the hard and soft phase is also found to increase with the thickness of the film. Monte Carlo simulations on a model three dimensional array of interacting nanomagnetic grains provide further insight into the effect of inter granular exchange interactions between the soft and hard phases. - Highlights: • L1_0-A1 FePt nanocomposites thin films of different thickness have been fabricated by DC sputtering. • Hysteresis curve measurements exhibit perfect single phase (L1_0) like behavior for thicker films. • SFD reveals that the openness of recoil curves is directly linked with the amount of uncoupled soft (A1) phase. • Monte Carlo simulation predicts that the extent of exchange interaction increases with thickness of the film.

Nuclear-Recoil Energy Scale in CDMS II Silicon Dark-Matter Detectors

Energy Technology Data Exchange (ETDEWEB)

Agnese, R.; et al.

2018-03-07

The Cryogenic Dark Matter Search (CDMS II) experiment aims to detect dark matter particles that elastically scatter from nuclei in semiconductor detectors. The resulting nuclear-recoil energy depositions are detected by ionization and phonon sensors. Neutrons produce a similar spectrum of low-energy nuclear recoils in such detectors, while most other backgrounds produce electron recoils. The absolute energy scale for nuclear recoils is necessary to interpret results correctly. The energy scale can be determined in CDMS II silicon detectors using neutrons incident from a broad-spectrum $^{252}$Cf source, taking advantage of a prominent resonance in the neutron elastic scattering cross section of silicon at a recoil (neutron) energy near 20 (182) keV. Results indicate that the phonon collection efficiency for nuclear recoils is $4.8^{+0.7}_{-0.9}$% lower than for electron recoils of the same energy. Comparisons of the ionization signals for nuclear recoils to those measured previously by other groups at higher electric fields indicate that the ionization collection efficiency for CDMS II silicon detectors operated at $\\sim$4 V/cm is consistent with 100% for nuclear recoils below 20 keV and gradually decreases for larger energies to $\\sim$75% at 100 keV. The impact of these measurements on previously published CDMS II silicon results is small.

RECOILING SUPERMASSIVE BLACK HOLES IN SPIN-FLIP RADIO GALAXIES

International Nuclear Information System (INIS)

Liu, F. K.; Wang Dong; Chen Xian

2012-01-01

Numerical relativity simulations predict that coalescence of supermassive black hole (SMBH) binaries leads not only to a spin flip but also to a recoiling of the merger remnant SMBHs. In the literature, X-shaped radio sources are popularly suggested to be candidates for SMBH mergers with spin flip of jet-ejecting SMBHs. Here we investigate the spectral and spatial observational signatures of the recoiling SMBHs in radio sources undergoing black hole spin flip. Our results show that SMBHs in most spin-flip radio sources have mass ratio q ∼> 0.3 with a minimum possible value q min ≅ 0.05. For major mergers, the remnant SMBHs can get a kick velocity as high as 2100 km s –1 in the direction within an angle ∼< 40° relative to the spin axes of remnant SMBHs, implying that recoiling quasars are biased to be with high Doppler-shifted broad emission lines while recoiling radio galaxies are biased to large apparent spatial off-center displacements. We also calculate the distribution functions of line-of-sight velocity and apparent spatial off-center displacements for spin-flip radio sources with different apparent jet reorientation angles. Our results show that the larger the apparent jet reorientation angle is, the larger the Doppler-shifting recoiling velocity and apparent spatial off-center displacement will be. We investigate the effects of recoiling velocity on the dust torus in spin-flip radio sources and suggest that recoiling of SMBHs would lead to 'dust-poor' active galactic nuclei. Finally, we collect a sample of 19 X-shaped radio objects and for each object give the probability of detecting the predicted signatures of recoiling SMBH.

Simulated Response of a Tissue-equivalent Proportional Counter on the Surface of Mars.

Science.gov (United States)

Northum, Jeremy D; Guetersloh, Stephen B; Braby, Leslie A; Ford, John R

2015-10-01

Uncertainties persist regarding the assessment of the carcinogenic risk associated with galactic cosmic ray (GCR) exposure during a mission to Mars. The GCR spectrum peaks in the range of 300(-1) MeV n to 700 MeV n(-1) and is comprised of elemental ions from H to Ni. While Fe ions represent only 0.03% of the GCR spectrum in terms of particle abundance, they are responsible for nearly 30% of the dose equivalent in free space. Because of this, radiation biology studies focusing on understanding the biological effects of GCR exposure generally use Fe ions. Acting as a thin shield, the Martian atmosphere alters the GCR spectrum in a manner that significantly reduces the importance of Fe ions. Additionally, albedo particles emanating from the regolith complicate the radiation environment. The present study uses the Monte Carlo code FLUKA to simulate the response of a tissue-equivalent proportional counter on the surface of Mars to produce dosimetry quantities and microdosimetry distributions. The dose equivalent rate on the surface of Mars was found to be 0.18 Sv y(-1) with an average quality factor of 2.9 and a dose mean lineal energy of 18.4 keV μm(-1). Additionally, albedo neutrons were found to account for 25% of the dose equivalent. It is anticipated that these data will provide relevant starting points for use in future risk assessment and mission planning studies.

Controlling low-rate signal path microdischarge for an ultra-low-background proportional counter

International Nuclear Information System (INIS)

Mace, E.K.; Aalseth, C.E.; Bonicalzi, R.M.; Day, A.R.; Hoppe, E.W.; Keillor, M.E.; Myers, A.W.; Overman, C.T.; Seifert, A.

2013-01-01

Pacific Northwest National Laboratory (PNNL) has developed an ultra-low-background proportional counter (ULBPC) made of high purity copper. These detectors are part of an ultra-low-background counting system (ULBCS) in the newly constructed shallow underground laboratory at PNNL (at a depth of ∼30 m water-equivalent). To control backgrounds, the current preamplifier electronics are located outside the ULBCS shielding. Thus the signal from the detector travels through ∼1 m of cable and is potentially susceptible to high voltage microdischarge and other sources of electronic noise. Based on initial successful tests, commercial cables and connectors were used for this critical signal path. Subsequent testing across different batches of commercial cables and connectors, however, showed unwanted (but still low) rates of microdischarge noise. To control this noise source, two approaches were pursued: first, to carefully validate cables, connectors, and other commercial components in this critical signal path, making modifications where necessary; second, to develop a custom low-noise, low-background preamplifier that can be integrated with the ULBPC and thus remove most commercial components from the critical signal path. This integrated preamplifier approach is based on the Amptek A250 low-noise charge-integrating preamplifier module. The initial microdischarge signals observed are presented and characterized according to the suspected source. Each of the approaches for mitigation is described, and the results from both are compared with each other and with the original performance seen with commercial cables and connectors. (author)

Compton recoil electron tracking with silicon strip detectors

International Nuclear Information System (INIS)

O'Neill, T.J.; Ait-Ouamer, F.; Schwartz, I.; Tumer, O.T.; White, R.S.; Zych, A.D.

1992-01-01

The application of silicon strip detectors to Compton gamma ray astronomy telescopes is described in this paper. The Silicon Compton Recoil Telescope (SCRT) tracks Compton recoil electrons in silicon strip converters to provide a unique direction for Compton scattered gamma rays above 1 MeV. With strip detectors of modest positional and energy resolutions of 1 mm FWHM and 3% at 662 keV, respectively, 'true imaging' can be achieved to provide an order of magnitude improvement in sensitivity to 1.6 x 10 - 6 γ/cm 2 -s at 2 MeV. The results of extensive Monte Carlo calculations of recoil electrons traversing multiple layers of 200 micron silicon wafers are presented. Multiple Coulomb scattering of the recoil electron in the silicon wafer of the Compton interaction and the next adjacent wafer is the basic limitation to determining the electron's initial direction

Recoil momenta distributions in the double photoionization

International Nuclear Information System (INIS)

Amusia, M Ya; Liverts, E Z; Drukarev, E G; Mikhai, A I

2014-01-01

We calculate the distributions in recoil momenta for the high energy double photoionization of helium caused by quasifree mechanism. The distributions obtain local maxima at small values of the recoil momenta. This agrees with earlier predictions and recent experimental data. Angular correlations which reach the largest value for 'back-to-back' configuration of photoelectrons are also obtained.

Measurement of Nuclear Recoils in the CDMS II Dark Matter Search

Science.gov (United States)

Fallows, Scott M.

The Cryogenic Dark Matter Search (CDMS) experiment is designed to directly detect elastic scatters of weakly-interacting massive dark matter particles (WIMPs), on target nuclei in semiconductor crystals composed of Si and Ge. These scatters would occur very rarely, in an overwhelming background composed primarily of electron recoils from photons and electrons, as well as a smaller but non-negligible background of WIMP-like nuclear recoils from neutrons. The CDMS~II generation of detectors simultaneously measure ionization and athermal phonon signals from each scatter, allowing discrimination against virtually all electron recoils in the detector bulk. Pulse-shape timing analysis allows discrimination against nearly all remaining electron recoils taking place near detector surfaces. Along with carefully limited neutron backgrounds, this experimental program allowed for "background-free'' operation of CDMS~II at Soudan, with less than one background event expected in each WIMP-search analysis. As a result, exclusionary upper-limits on WIMP-nucleon interaction cross section were placed over a wide range of candidate WIMP masses, ruling out large new regions of parameter space. These results, like any others, are subject to a variety of systematic effects that may alter their final interpretations. A primary focus of this dissertation will be difficulties in precisely calibrating the energy scale for nuclear recoil events like those from WIMPs. Nuclear recoils have suppressed ionization signals relative to electron recoils of the same recoil energy, so the response of the detectors is calibrated differently for each recoil type. The overall normalization and linearity of the energy scale for electron recoils in CDMS~II detectors is clearly established by peaks of known gamma energy in the ionization spectrum of calibration data from a 133Ba source. This electron-equivalent keVee) energy scale enables calibration of the total phonon signal (keVt) by enforcing unity

Commissioning of the recoil silicon detector for the HERMES experiment

International Nuclear Information System (INIS)

Pickert, N.C.

2008-02-01

The reconstruction of the missing mass is limited by the position and momentum resolution of the HERMES spectrometer. In order to reach a higher accuracy in the measurements the backscattered nucleon must also be detected. A detector suited for this must give the possibility, to determine the momentum of the particles over a very large range: from minimally ionizing particles up to protons, which are stopped in the detector. The detector must also be able to discriminate hadrons and mesons as well as cover the complete spatial region around the target. In the winter 2005-2006 such a recoil detector was installed in the HERMES experiment. The detector sonsists of three partial detectors, a silicon counter within the scattering chamber, a sintillating-fiber detector and a photon detector. Before the installation of the detector the silicon modules were tested in a bench test and checked together with the other particle detectors in a test experiment. A large part of this dissertation is dedicated to the planning and performance of these tests as well to the evaluation of them. It could be show, that the modules worked accordly to their specifications, however because of unexpectedly high noise a signal correction became necessary. Different models for the correction were developed and tested in the framework of these thesis. In spite of the high noise cosmic muons could be detected and their energy deposition measured with a signal-to-noise ratio of 2:1. In the winter break 2005-2006 the recoil detector was installed into the HERMES experiment. First diagnosis and analysis software was developed. The silicon detector measured successfully energy depositions of minimally ionizing particles up to protons stopped in the sensor. Minimally ionizing particles could be detected with a signal-to-noise ratio of 5:1. By means of track information of the scintillating-fiber detector protons could be discriminated from pions and other mesons by the silicon detector. The HERMES

Commissioning of the recoil silicon detector for the HERMES experiment

Energy Technology Data Exchange (ETDEWEB)

Pickert, N C

2008-02-15

The reconstruction of the missing mass is limited by the position and momentum resolution of the HERMES spectrometer. In order to reach a higher accuracy in the measurements the backscattered nucleon must also be detected. A detector suited for this must give the possibility, to determine the momentum of the particles over a very large range: from minimally ionizing particles up to protons, which are stopped in the detector. The detector must also be able to discriminate hadrons and mesons as well as cover the complete spatial region around the target. In the winter 2005-2006 such a recoil detector was installed in the HERMES experiment. The detector sonsists of three partial detectors, a silicon counter within the scattering chamber, a sintillating-fiber detector and a photon detector. Before the installation of the detector the silicon modules were tested in a bench test and checked together with the other particle detectors in a test experiment. A large part of this dissertation is dedicated to the planning and performance of these tests as well to the evaluation of them. It could be show, that the modules worked accordly to their specifications, however because of unexpectedly high noise a signal correction became necessary. Different models for the correction were developed and tested in the framework of these thesis. In spite of the high noise cosmic muons could be detected and their energy deposition measured with a signal-to-noise ratio of 2:1. In the winter break 2005-2006 the recoil detector was installed into the HERMES experiment. First diagnosis and analysis software was developed. The silicon detector measured successfully energy depositions of minimally ionizing particles up to protons stopped in the sensor. Minimally ionizing particles could be detected with a signal-to-noise ratio of 5:1. By means of track information of the scintillating-fiber detector protons could be discriminated from pions and other mesons by the silicon detector. The HERMES

Origin of open recoil curves in L1{sub 0}-A1 FePt exchange coupled nanocomposite thin film

Energy Technology Data Exchange (ETDEWEB)

Goyal, Rajan [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India); Kapoor, Akanksha [M. Tech Nanoscience and Nanotechnology, University of Delhi, Delhi 110007 (India); Lamba, S. [School of Sciences, Indira Gandhi National Open University, New Delhi 110068 (India); Annapoorni, S., E-mail: annapoornis@yahoo.co.in [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India)

2016-11-15

Mixed phase FePt systems with intergranular coupling may be looked upon as natural exchange spring systems. The coupling strength between the soft and hard phase in these systems can be analyzed using recoil curves. However, the origin of open recoil curves depicting the breakdown of exchange coupling or anisotropy variation in hard phase is still an ambiguity and requires an in-depth analysis. In order to investigate this, an analysis of the recoil curves for L1{sub 0}–A1 FePt nanocomposite thin films of varying thickness have been performed. The switching field distribution reveals that the maximum of openness of recoil curve is directly proportional to the amount of uncoupled soft phase present in the system. The coupling between the hard and soft phase is also found to increase with the thickness of the film. Monte Carlo simulations on a model three dimensional array of interacting nanomagnetic grains provide further insight into the effect of inter granular exchange interactions between the soft and hard phases. - Highlights: • L1{sub 0}-A1 FePt nanocomposites thin films of different thickness have been fabricated by DC sputtering. • Hysteresis curve measurements exhibit perfect single phase (L1{sub 0}) like behavior for thicker films. • SFD reveals that the openness of recoil curves is directly linked with the amount of uncoupled soft (A1) phase. • Monte Carlo simulation predicts that the extent of exchange interaction increases with thickness of the film.

Pulse formation of gas-filled counter

International Nuclear Information System (INIS)

Iwatani, Kazuo; Teshima, Kazunori; Shizuma, Kiyoshi; Hasai, Hiromi

1991-01-01

The pulse formation of gas-filled counter has been calculated by simple models for the proportional and self-quenching streamer (SQS) modes. Calculated pulse shapes of counter output have accurately reproduced the observed ones for both modes. As a result, it is shown that the special density distribution of ion pairs in a streamer can be estimated with the rising part of observed pulse shape, using the model. (author)

New proportional counter for in vivo detection of traces of plutonium in the lungs; Nouveau compteur proportionnel destine a la detection in vivo de traces de plutonium dans les poumons

Energy Technology Data Exchange (ETDEWEB)

Morucci, J [Commissariat a l' Energie Atomique, Centre d' Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France)

1966-07-01

Development of a multi-wire proportional counter having a uniform response over 250 cm{sup 2} thanks to corrections made for boundary effects, and having a low background per sq. cm. due to the use of two identical counters set in anti-coincidence in the same enclosure is described. (author) [French] Etude et mise au point d'un compteur proportionnel multifils de reponse utile homogene sur une surface de 250 cm{sup 2} grace a la correction des effets de bords et de faible mouvement propre par cm{sup 2} grace a deux compteurs identiques montes en anticoincidence dans la meme enceinte. (auteur)

Time-of-flight scattering and recoiling spectrometry

International Nuclear Information System (INIS)

Rabalais, J.W.

1991-01-01

Ion scattering and recoiling spectrometry consists of directing a collimated beam of monoenergetic ions towards a surface and measuring the flux of scattered and recoiled particles from this surface. When the neutral plus ion flux is velocity selected by measuring the flight times from the sample to the detector, the technique is called time-of-flight scattering and recoiling spectrometry (TOF-SARS). TOF-SARS is capable of (1) surface elemental analysis by applying classical mechanics to the velocities of the particles, (2) surface structural analysis by monitoring the angular anisotropies in the particle flux, and (3) ion-surface electron exchange probabilities by analysis of the ion/neutral fractions in the particle flux. Examples of these three areas are presented herein

Nuclear targets, recoil ion catchers and reaction chambers

NARCIS (Netherlands)

Dionisio, JS; Vieu, C; Schuck, C; Collatz, R; Meunier, R; Ledu, D; Folger, H; Lafoux, A; Lagrange, JM; Pautrat, M; Waast, B; Phillips, WR; Blunt, D; Durell, JL; Varley, BJ; Dagnall, PG; Dorning, SJ; JONES, MA; Smith, AG; Bacelar, JCS; Rzaca-Urban, T; Amzal, N; Meliani, Z; Vanhorenbeeck, J; Passoja, A; Urban, W

1998-01-01

The main features of nuclear targets, recoil ion catchers and reaction chambers used in nuclear spectroscopic investigations involving in-beam multi-e-gamma spectrometers are discussed. The relative importance of the F-ray background due to the accelerated ion-target and the recoil-ion-target

Neutron spectrometry measurements in iron

International Nuclear Information System (INIS)

Perlini, G.; Acerbis, S.; Carter, M.

1988-01-01

A compact structure was prepared for use in making measurements of neutron penetration in iron which could serve as reference data and as a check for computer codes. About 30 iron plates were put together giving a useful overall length of 130 cm. At various depths along the central axis of the iron block, measurements were made with liquid scintillator spectrometers and proton recoil proportional counters. The energy band explored was between 14 KeV and 10 MeV. Here we report the original spectra of the impulses and the neutron spectra found by the NE213 code based on the differential method and by unfolding with the SPEC4 code for liquid scintillation counters and proton recoil spectrometers, respectively. 12 figs., 60 tabs., 6 refs

Recoil effects of neutron-irradiated metal salts

International Nuclear Information System (INIS)

Lee, B.H.

1980-01-01

The distribution of sup(56)Mn and sup(38)Cl recoil species following radiative neutron capture permanganates, chlorates and perchlorates has been investigated by using ion-exchange chromatography method. The whole of the sup(56)Mn radioactivity in permanganates appeared in two valence states, the sup(38)Cl radioactivity in chlorates in two valence states and also the sup(38)Cl radioactivity in perchlorates in three valence states. Recoil energy was calculated. The internal conversion of sup(38m)Cl isomer transition affects the retention value. The greater the radii of the cation, the higher is the probability of the recoil atom breaking through the secondary cage. In ammonium salt, the ammonium ion behaves as a reducing agent. Crystal structures with their greater free space have shown by retention. (Author)

Transportation system of recoil nucleus by helium jet

International Nuclear Information System (INIS)

Cabral, S.C.; Borges, A.M.; Lemos Junior, O.F.; Auler, L.T.; Silva, A.G. da

1981-01-01

The transportation system of recoil nucleus by helium jet, is studied. It is used a technique aiming to put in the detection area (region of low background) the recoils, produced by nuclear reactions between target and particle beams, those produced with the help of cyclotron CV-28. (E.G.) [pt

Azimuthal spread of the avalanche in proportional chambers

International Nuclear Information System (INIS)

Okuno, H.; Fischer, J.; Radeka, V.; Walenta, A.H.

1978-10-01

The angular distribution of the avalanche around the anode wire in the gas proportional counter is determined by measuring the distribution of positive ions arriving on cathode strips surrounding the anode wire for each single event. The shape and width of the distribution depend on such factors as the gas gain, the anode diameter, the counting gas and the primary ionization density. Effects of these factors are studied systematically, and their importance for practical counter applications is discussed

Measurement and analysis of neutron flux distribution of STACY heterogeneous core by position sensitive proportional counter. Contract research

CERN Document Server

Murazaki, M; Uno, Y

2003-01-01

We have measured neutron flux distribution around the core tank of STACY heterogeneous core by position sensitive proportional counter (PSPC) to develop the method to measure reactivity for subcritical systems. The neutron flux distribution data in the position accuracy of +-13 mm have been obtained in the range of uranium concentration of 50g/L to 210g/L both in critical and in subcritical state. The prompt neutron decay constant, alpha, was evaluated from the measurement data of pulsed neutron source experiments. We also calculated distribution of neutron flux and sup 3 He reaction rates at the location of PSPC by using continuous energy Monte Carlo code MCNP. The measurement data was compared with the calculation results. As results of comparison, calculated values agreed generally with measurement data of PSPC with Cd cover in the region above half of solution height, but the difference between calculated value and measurement data was large in the region below half of solution height. On the other hand, ...

Heavy quark symmetry at large recoil: The case of baryons

International Nuclear Information System (INIS)

Koerner, J.G.; Kroll, P.

1992-02-01

We analyze the large recoil behaviour of heavy baryon transition form factors in semi-leptonic decays. We use a generalized Brodsky-Lepage hard scattering formalism where diquarks are considered as quasi-elementary constituents of baryons. In the limit of infinitely heavy quark masses the large recoil form factors exhibit a new model-independent heavy quark symmetry which is reminiscent but not identical to the Isgur-Wise symmetry at low recoil. (orig.)

The x-ray spectrum of the Cygnus Loop measured with Gas Scintillation Proportional Counters

International Nuclear Information System (INIS)

Tsunemi, Hiroshi; Manabe, Makoto; Yamashita, Koujun; Koyama, Katsuji.

1988-01-01

We report the results of an observation of the whole Cygnus Loop performed with the Gas Scintillation Proportional Counters (GSPC) on board the Tenma satellite. Line emissions around 1.9 keV and 2.5 keV, probably originating from silicon and sulfur Kα line blends, were detected. The continuum spectrum in the energy range 1-3 keV can be represented by a thermal bremsstrahlung spectrum with a temperature of 7 x 10 6 K. This is the highest value for the Cygnus Loop reported so far. The Tenma data were also combined with those from a sounding rocket flight performed previously, in which a similar detector system was employed. Thus, we obtain a wide-band X-ray spectrum for the whole Cygnus Loop with the best energy resolution reported so far. The combined data could not be fitted by a single temperature component in the thermal collisional ionization equilibrium (CIE) model or a single-temperature nonequilibrium ionization (NEI) model. A good fit is obtained if at least two temperature components are included in both the CIE and NEI models. However, only the NEI model allows a self consistent interpretation. Taking into account the emission measures for both components, we can conclude that the low-temperature, high-density component arises mainly from the shell region and that the high-temperature, low-density component arises from the interior of the shell. (author)

Recoil release of fission products from nuclear fuel

International Nuclear Information System (INIS)

Wise, C.

1985-01-01

An analytical approximation is developed for calculating recoil release from nuclear fuel into gas filled interspaces. This expression is evaluated for a number of interspace geometries and shown to be generally accurate to within about 10% by comparison with numerical calculations. The results are applied to situations of physical interest and it is demonstrated that recoil can be important when modelling fission product release from low temperature CAGR pin failures. Furthermore, recoil can contribute significantly in experiments on low temperature fission product release, particularly where oxidation enhancement of this release is measured by exposing the fuel to CO 2 . The calculations presented here are one way of allowing for this, other methods are suggested. (orig.)

Shallow doping of gallium arsenide by recoil implantation

International Nuclear Information System (INIS)

Sadana, D.K.; Souza, J.P. de; Rutz, R.F.; Cardone, F.; Norcott, M.H.

1989-01-01

Si atoms were recoil-implanted into GaAs by bombarding neutral (As + ) or dopant (Si + ) ions through a thin Si cap. The bombarded samples were subsequently rapid thermally or furnace annealed at 815-1000 degree C in Ar or arsine ambient. The presence of the recoiled Si in GaAs and resulting n + -doping was confirmed by secondary ion mass spectrometry and Hall measurements. It was found that sheet resistance of 19 cm 3 and the annealing temperature was > 850 degree C. The present electrical data show that the recoil implant method is a viable alternative to direct shallow implant for n + doping of GaAs. 7 refs., 3 figs., 1 tab

Submillisecond Elastic Recoil Reveals Molecular Origins of Fibrin Fiber Mechanics

Science.gov (United States)

Hudson, Nathan E.; Ding, Feng; Bucay, Igal; O’Brien, E. Timothy; Gorkun, Oleg V.; Superfine, Richard; Lord, Susan T.; Dokholyan, Nikolay V.; Falvo, Michael R.

2013-01-01

Fibrin fibers form the structural scaffold of blood clots. Thus, their mechanical properties are of central importance to understanding hemostasis and thrombotic disease. Recent studies have revealed that fibrin fibers are elastomeric despite their high degree of molecular ordering. These results have inspired a variety of molecular models for fibrin’s elasticity, ranging from reversible protein unfolding to rubber-like elasticity. An important property that has not been explored is the timescale of elastic recoil, a parameter that is critical for fibrin’s mechanical function and places a temporal constraint on molecular models of fiber elasticity. Using high-frame-rate imaging and atomic force microscopy-based nanomanipulation, we measured the recoil dynamics of individual fibrin fibers and found that the recoil was orders of magnitude faster than anticipated from models involving protein refolding. We also performed steered discrete molecular-dynamics simulations to investigate the molecular origins of the observed recoil. Our results point to the unstructured αC regions of the otherwise structured fibrin molecule as being responsible for the elastic recoil of the fibers. PMID:23790375

Einstein Observatory SSS and MPC observations of the complex X-ray spectra of Seyfert galaxies. [Solid State Spectrometer and Monitor Proportional Counter

Science.gov (United States)

Turner, T. J.; Weaver, K. A.; Mushotzky, R. F.; Holt, S. S.; Madejski, G. M.

1991-01-01

The X-ray spectra of 25 Seyfert galaxies measured with the Solid State Spectrometer on the Einstein Observatory have been investigated. This new investigation utilizes simultaneous data from the Monitor Proportional Counter, and automatic correction for systematic effects in the Solid State Spectrometer which were previously handled subjectively. It is found that the best-fit single-power-law indices generally agree with those previously reported, but that soft excesses of some form are inferred for about 48 percent of the sources. One possible explanation of the soft excess emission is a blend of soft X-ray lines, centered around 0.8 keV. The implications of these results for accretion disk models are discussed.

Simultaneous measurement of tritium and radiocarbon by ultra-low-background proportional counting.

Science.gov (United States)

Mace, Emily; Aalseth, Craig; Alexander, Tom; Back, Henning; Day, Anthony; Hoppe, Eric; Keillor, Martin; Moran, Jim; Overman, Cory; Panisko, Mark; Seifert, Allen

2017-08-01

Use of ultra-low-background capabilities at Pacific Northwest National Laboratory provide enhanced sensitivity for measurement of low-activity sources of tritium and radiocarbon using proportional counters. Tritium levels are nearly back to pre-nuclear test backgrounds (~2-8 TU in rainwater), which can complicate their dual measurement with radiocarbon due to overlap in the beta decay spectra. We present results of single-isotope proportional counter measurements used to analyze a dual-isotope methane sample synthesized from ~120mg of H 2 O and present sensitivity results. Copyright © 2017 Elsevier Ltd. All rights reserved.

Direct Measurement of Photon Recoil from a Levitated Nanoparticle

Science.gov (United States)

Jain, Vijay; Gieseler, Jan; Moritz, Clemens; Dellago, Christoph; Quidant, Romain; Novotny, Lukas

2016-06-01

The momentum transfer between a photon and an object defines a fundamental limit for the precision with which the object can be measured. If the object oscillates at a frequency Ω0 , this measurement backaction adds quanta ℏΩ0 to the oscillator's energy at a rate Γrecoil, a process called photon recoil heating, and sets bounds to coherence times in cavity optomechanical systems. Here, we use an optically levitated nanoparticle in ultrahigh vacuum to directly measure Γrecoil. By means of a phase-sensitive feedback scheme, we cool the harmonic motion of the nanoparticle from ambient to microkelvin temperatures and measure its reheating rate under the influence of the radiation field. The recoil heating rate is measured for different particle sizes and for different excitation powers, without the need for cavity optics or cryogenic environments. The measurements are in quantitative agreement with theoretical predictions and provide valuable guidance for the realization of quantum ground-state cooling protocols and the measurement of ultrasmall forces.

Contributions to the methodology of multiwire proportional chambers

International Nuclear Information System (INIS)

Petrascu, H.

1993-01-01

The Ph.D. thesis presents first the realization, testing, optimization, and use of detection equipment based on position sensitive multiwire proportional chambers (MWPC), high resolution proportional counters, and of ΔE,E ionization chambers. In the second chapter it is presented the realization MWPC, in which the coordinate information is obtained by means of LC-delay lines, containing many original constructive elements. By using a system of three MWPC in coincidence, an experimental testing of the theoretically predicted pion generation in the 235 U fission process, was performed. An upper limit of 10 -11 for this process was found. In the 3-rd chapter there are presented the developments of high resolution proportional counters for X-ray spectrometry. Various penning mixtures of high purity gases were studied. The purity of gases was assured by a technology described in a Romanian patents. These counters are currently use in various applications as a rapid analysis of steel marks and in the mining industry. the 4-th chapter is dedicated to the construction and using of ΔE,E closed, high resolution ionization chambers. With these chambers the multinucleon transfer in the 27 Al( 14 M, X) reaction at 116 MeV bombarding energy was investigated. Also this type of chambers was used for the elaboration of an absolute method for analysis and profiling of impurities in silicon wafers. This method is described in the last part of the chapter. (Author) 117 Figs., 8 Tabs., 55 Refs

Electric form factor of the proton through recoil polarization

International Nuclear Information System (INIS)

Punjabi, V.

2000-01-01

The electromagnetic form factors of the nucleon, G E and G M , describe the charge and current distribution inside the nucleon and thus are quite intimately related to its structure. Jefferson Lab experiment 93-027 measured P l and Pt, the longitudinal and transverse recoil proton polarization, respectively, for the 1 H(e-vector,e'p-vector) reaction in the four-momentum transfer squared range of 0.5 to 3.5 GeV 2 , using the Hall A facility with two high resolution spectrometers and a Focal Plane Polarimeter. The ratio G Ep /G Mp is directly proportional to the ratio P t /P l . These data have unprecedented precision, and show for the first time that the Q 2 dependence of G Ep and G Mp is very different. (author)

On the M\\"ossbauer effect and the rigid recoil question

OpenAIRE

Davidson, Mark

2016-01-01

Various theories for the M\\"ossbauer rigid-recoil effect, which enables a crystal to absorb momentum but not appreciable energy, are compared. These suggest that the recoil may not be instantaneous, and that the recoil time could be used to distinguish between them. An experiment is proposed to measure this time. The idea is to use a small sphere whose outer surface is coated with an electrically charged M\\"ossbauer-active element, and then to measure the amount of energy lost due to Bremmsst...

Hydrogen analysis by elastic recoil spectrometry

International Nuclear Information System (INIS)

Tirira, J.; Trocellier, P.

1989-01-01

An absolute, quantitative procedure was developed to determine the hydrogen content and to describe its concentration profile in the near-surface region of solids. The experimental technique used was the elastic recoil detection analysis of protons induced by 4 He beam bombardment in the energy range <=1.8 MeV. The hydrogen content was calculated using a new recoil cross section expression. The analyses were performed in silicon crystals implanted with hydrogen at 10 keV. The implantation dose was evaluated with an accuracy of 10% and the hydrogen depth profile with that of +-10 nm around 200 nm. (author) 10 refs.; 3 figs

Submillisecond elastic recoil reveals molecular origins of fibrin fiber mechanics.

Science.gov (United States)

Hudson, Nathan E; Ding, Feng; Bucay, Igal; O'Brien, E Timothy; Gorkun, Oleg V; Superfine, Richard; Lord, Susan T; Dokholyan, Nikolay V; Falvo, Michael R

2013-06-18

Fibrin fibers form the structural scaffold of blood clots. Thus, their mechanical properties are of central importance to understanding hemostasis and thrombotic disease. Recent studies have revealed that fibrin fibers are elastomeric despite their high degree of molecular ordering. These results have inspired a variety of molecular models for fibrin's elasticity, ranging from reversible protein unfolding to rubber-like elasticity. An important property that has not been explored is the timescale of elastic recoil, a parameter that is critical for fibrin's mechanical function and places a temporal constraint on molecular models of fiber elasticity. Using high-frame-rate imaging and atomic force microscopy-based nanomanipulation, we measured the recoil dynamics of individual fibrin fibers and found that the recoil was orders of magnitude faster than anticipated from models involving protein refolding. We also performed steered discrete molecular-dynamics simulations to investigate the molecular origins of the observed recoil. Our results point to the unstructured αC regions of the otherwise structured fibrin molecule as being responsible for the elastic recoil of the fibers. Copyright © 2013 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Measurement and analysis of neutron flux distribution of STACY heterogeneous core by position sensitive proportional counter. Contract research

Energy Technology Data Exchange (ETDEWEB)

Murazaki, Minoru; Uno, Yuichi; Miyoshi, Yoshinori [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

2003-03-01

We have measured neutron flux distribution around the core tank of STACY heterogeneous core by position sensitive proportional counter (PSPC) to develop the method to measure reactivity for subcritical systems. The neutron flux distribution data in the position accuracy of {+-}13 mm have been obtained in the range of uranium concentration of 50g/L to 210g/L both in critical and in subcritical state. The prompt neutron decay constant, {alpha}, was evaluated from the measurement data of pulsed neutron source experiments. We also calculated distribution of neutron flux and {sup 3}He reaction rates at the location of PSPC by using continuous energy Monte Carlo code MCNP. The measurement data was compared with the calculation results. As results of comparison, calculated values agreed generally with measurement data of PSPC with Cd cover in the region above half of solution height, but the difference between calculated value and measurement data was large in the region below half of solution height. On the other hand, calculated value agreed well with measurement data of PSPC without Cd cover. (author)

Recoil ion charge state distributions in low energy Arq+ - Ar collisions

International Nuclear Information System (INIS)

Vancura, J.; Marchetti, V.; Kostroun, V.O.

1992-01-01

We have measured the recoil ion charge state distributions in Ar q+ -- Ar (8≤q≤16) collisions at 2.3 qkeV and 0.18qkeV by time of flight (TOF) spectroscopy. For Ar 8-16+ , recoil ion charge states up to 6+ are clearly present, indicating that the 3p subshell in the target atom is being depleted, while for Ar 10-16+ , there is evidence that target 3s electrons are also being removed. Comparison of the recoil ion charge state spectra at 2.3 and 0.18 qkeV shows that for a given projectile charge, there is very little dependence of the observed recoil target charge state distribution on projectile energy

RECOILING MASSIVE BLACK HOLES IN GAS-RICH GALAXY MERGERS

International Nuclear Information System (INIS)

Guedes, Javiera; Madau, Piero; Mayer, Lucio; Callegari, Simone

2011-01-01

The asymmetric emission of gravitational waves produced during the coalescence of a massive black hole (MBH) binary imparts a velocity 'kick' to the system that can displace the hole from the center of its host. Here, we study the trajectories and observability of MBHs recoiling in three (one major, two minor) gas-rich galaxy merger remnants that were previously simulated at high resolution, and in which the pairing of the MBHs had been shown to be successful. We run new simulations of MBHs recoiling in the major merger remnant with Mach numbers in the range 1≤M≤6 and use simulation data to construct a semi-analytical model for the orbital evolution of MBHs in gas-rich systems. We show the following. (1) In major merger remnants the energy deposited by the moving hole into the rotationally supported, turbulent medium makes a negligible contribution to the thermodynamics of the gas. This contribution becomes significant in minor merger remnants, potentially allowing for an electromagnetic signature of MBH recoil. (2) In major merger remnants, the combination of both deeper central potential well and drag from high-density gas confines even MBHs with kick velocities as high as 1200 km s -1 within 1 kpc from the host's center. (3) Kinematically offset nuclei may be observable for timescales of a few Myr in major merger remnants in the case of recoil velocities in the range 700-1000 km s -1 . (4) In minor merger remnants the effect of gas drag is weaker, and MBHs with recoil speeds in the range 300-600 km s -1 will wander through the host halo for longer timescales. When accounting for the probability distribution of kick velocities, however, we find that the likelihood of observing recoiling MBHs in gas-rich galaxy mergers is very low even in the best-case scenario.

Enhancing the sensitivity of recoil-beta tagging

International Nuclear Information System (INIS)

Henderson, J; Jenkins, D G; Davies, P J; Henry, T W; Joshi, P; Nichols, A J; Ruotsalainen, P; Scholey, C; Auranen, K; Grahn, T; Greenlees, P T; Herzáň, A; Jakobsson, U; Julin, R; Juutinen, S; Konki, J; Leino, M; Pakarinen, J; Lotay, G; Obertelli, A

2013-01-01

Tagging with β-particles at the focal plane of a recoil separator has been shown to be an effective technique for the study of exotic proton-rich nuclei. This article describes three new pieces of apparatus used to greatly improve the sensitivity of the recoil-beta tagging technique. These include a highly-pixelated double-sided silicon strip detector, a plastic phoswich detector for discriminating high-energy β-particles, and a charged-particle veto box. The performance of these new detectors is described and characterised, and the resulting improvements are discussed.

Realisation and qualification of a tissue equivalent proportional counter with a multi-cellular geometry for the individual neutron dosimetry

International Nuclear Information System (INIS)

Hoflack, Ch.

1999-01-01

The present day dosimetry means for radiations with a strong ionization density cannot fulfill the future radioprotection regulations which will require an individual dosimetry with active dosemeters. The aim of this work is the study and development of an individual dosemeter based on a tissue equivalent proportional counter and with a multi-cellular geometry allowing to reach a sensibility equivalent to environmental dosemeters. A pressure regulation bench has been added to the detector in order to reduce the degassing of the detector parts and to reach a sufficient service life for the implementation of the characterization tests. The hole counter system has been adopted for the first prototypes in order to reduce the sensibility of the wires multiplication system with respect to mechanical vibrations. Tests performed with an internal alpha source have shown that a better electrical efficiency can be reached when more severe mechanical limits are adopted during the construction. The dose equivalent response of the prototype for mono-energy neutrons of 144 keV to 2.5 MeV is analyzed experimentally and by simulation. During experiments with normal incidence neutrons, the prototype fulfills the requirements of the CEI N O 1323 standard for energies comprised between 400 keV and 2.5 MeV, while the simulation indicates a satisfactory response up to 200 keV. A preliminary study of the behaviour of the detector with respect to the neutrons incidence indicates that the multi-cellular geometry is efficient for large angles (the sensibility of the prototype is increased by a factor 3). Finally, simulation studies have to be made to optimize the electrical operation and the geometry of the next prototype. (J.S.)

Comparison of the Recoil of Conventional and Electromagnetic Cannon

Directory of Open Access Journals (Sweden)

Edward M. Schmidt

2001-01-01

Full Text Available The recoil from an electromagnetic (EM railgun is discussed and compared with that from conventional, propellant gas driven cannon. It is shown that, under similar launch conditions, the recoil of the EM gun is less than that of the powder gun; however, use of a muzzle brake on a powder gun can alter this relative behavior.

Self-triggering detectors for recoil nuclei

International Nuclear Information System (INIS)

Aleksanyan, A.S.; Asatiani, T.I.; Gasparyan, A.O.

1975-01-01

Hybrid α-detectors consisting of wide gap spark chambers and signal α detectors are described. The investigations have been carried out with γ-beams of Yerevan Electron Synchrotron. The possibility of using such detectors in the experiments on particle photoproduction on gas helium with the determination of the interaction point, emission angle of the recoil nucleus and its energy by means of range measurement has been shown. It has been shown that self - triggering wide gap spark chamber allows to detect and measure the range of the recoil nuclei α-particles with energies Esub(α) > or approximately (1 - 2) Mev which correspond to momentum transfers apprxomation (10 -2 - 10 -3 ) (GeV/c) 2

Discrimination capability of avalanche counters detecting different ionizing particles

International Nuclear Information System (INIS)

Prete, G.; Viesti, G.; Padua Univ.

1985-01-01

The discrimination capability of avalanche counters to detect different ionizing particles has been studied using a 252 Cf source. Pulse height, pulse-height resolution and timing properties have been measured as a function of the reduced applied voltage for parallel-plate and parallel-grid avalanche counters. At the highest applied voltages, space charge effects shift the pulse-height signal of the avalanche counter away from being linearly proportional to the stopping power of the detected particles and cause the pulse-height resolution to deteriorate. To optimize the avalanche counter capability, without loss of time resolution, it appears better to operate the detector at voltages well below the breakdown threshold. Measurements with 32 S ions are also reported. (orig.)

Commissioning of a proton-recoil spectrometer

International Nuclear Information System (INIS)

Nunes, J.C.; Faught, R.T.

2000-01-01

Measurements of neutron fluence spectra in fields from bare and heavy-water-moderated 252 Cf were made with a commercially available proton-recoil spectrometer (PRS) that covers 50 keV to 4.5 MeV. Data obtained from these measurements were compared with data from Bonner sphere spectrometry, Monte Carlo simulation and the open literature. Alterations to the input data file used in unfolding recoil-proton pulse-height distributions were made. Understanding the reasons for these changes and considering the effects of some of the results in an appreciation of the significance of parameters used in the unfolding. An uncertainty of 10% is estimated for values of fluence and ambient dose equivalent for the energy region covered by this PRS. (author)

Simultaneous measurement of tritium and radiocarbon by ultra-low-background proportional counting

Energy Technology Data Exchange (ETDEWEB)

Mace, Emily; Aalseth, Craig; Alexander, Tom; Back, Henning; Day, Anthony; Hoppe, Eric; Keillor, Martin; Moran, Jim; Overman, Cory; Panisko, Mark; Seifert, Allen

2017-08-01

Use of ultra-low-background capabilities at Pacific Northwest National Laboratory provide enhanced sensitivity for measurement of low-activity sources of tritium and radiocarbon using proportional counters. Tritium levels are nearly back to pre-nuclear test backgrounds (~2-8 TU in rainwater), which can complicate their dual measurement with radiocarbon due to overlap in the isotope’s respective energy spectra. This activity makes direct dual-isotope measurements challenging without additional chemistry to concentrate the tritium in a sample. We present results of single-isotope proportional counter measurements used to analyze a dual-isotope methane sample synthesized from ~120 mg of H2O and present sensitivity results.

Proportional gas scintillation detectors and their applications

International Nuclear Information System (INIS)

Petr, I.

1978-01-01

The principle is described of a gas proportional scintillation detector and its function. Dependence of Si(Li) and xenon proportional detectors energy resolution on the input window size is given. A typical design is shown of a xenon detector used for X-ray spetrometry at an energy of 277 eV to 5.898 keV and at a gas pressure of 98 to 270 kPa. Gas proportional scintillation detectors show considerable better energy resolution than common proportional counters and even better resolution than semiconductor Si(Li) detectors for low X radiation energies. For detection areas smaller than 25 mm 2 Si(Li) detectors show better resolution, especially for higher X radiation energies. For window areas 25 to 190 mm 2 both types of detectors are equal, for a window area exceeding 190 mm 2 the proportional scintillation detector has higher energy resolution. (B.S.)

Multiwire proportional chamber for Moessbauer spectroscopy: development and results

International Nuclear Information System (INIS)

Costa, M.S. da.

1985-12-01

A new Multiwere proportional Chamber designed for Moessbauer Spectroscopy is presented. This detector allows transmission backscattering experiments using either photons or electrons. The Moessbauer data acquisition system, partially developed for this work is described. A simple method for determining the frontier between true proportional and semi-proportional regions of operation in gaseous detectors is proposed. The study of the tertiary gas mixture He-Ar-CH 4 leads to a straight forward way of energy calibration of the electron spectra. Moessbauer spectra using Fe-57 source are presented. In particular those obtained with backsattered electrons show the feasibility of depth selective analysis with gaseous proportional counters. (author) [pt

D-particle Recoil Space Times and "Glueball" Masses

CERN Document Server

Mavromatos, Nikolaos E; Mavromatos, Nick E.; Winstanley, Elizabeth

2001-01-01

We discuss the properties of matter in a D-dimensional anti-de-Sitter-type space time induced dynamically by the recoil of a very heavy D(irichlet)-particle defect embedded in it. The particular form of the recoil geometry, which from a world-sheet view point follows from logarithmic conformal field theory deformations of the pertinent sigma-models, results in the presence of both infrared and ultraviolet (spatial) cut-offs. These are crucial in ensuring the presence of mass gaps in scalar matter propagating in the D-particle recoil space time. The analogy of this problem with the Liouville-string approach to QCD, suggested earlier by John Ellis and one of the present authors, prompts us to identify the resulting scalar masses with those obtained in the supergravity approach based on the Maldacena's conjecture, but without the imposition of any supersymmetry in our case. Within reasonable numerical uncertainties, we observe that agreement is obtained between the two approaches for a particular value of the ra...

An Expansion Method to Unfold Proton Recoil Spectra

Energy Technology Data Exchange (ETDEWEB)

Kockum, J

1970-07-01

A method is given to obtain a good estimate of the input neutron spectrum from a pulse-height distribution measured with proportional counters filled with a hydrogenous gas. The method consists of expanding the sought estimate as a product of two functions where one is obtained by differentiating the pulse-height distribution and the other is a power series of the neutron energy. The coefficients of this series are determined by a least-squares fit of the calculated pulse-height distribution to the measured one. The method has been tested on pulse-height distributions obtained by calculations from a realistic neutron spectrum and response functions for a spherical counter 3. 94 cm in diameter and filled with 7 atm. of methane and 1 atm. of hydrogen, respectively. In the former case it is possible with the method described, to unfold pulse-height distributions up to a neutron energy of about 3 MeV to within 10 % of the input spectrum. The differentiating procedure included in the method ensures that all spectral details not smoothed out by the finite resolution of the counter, are kept in the spectrum estimate. A realistic estimate of the statistical uncertainty of each neutron spectrum value is given. Some of the possible systematical errors caused by uncertainties in input data have been investigated.

The response of a spherical tissue-equivalent proportional counter to 56-Fe particles from 200-1000 MeV/nucleon

Energy Technology Data Exchange (ETDEWEB)

Gersey, Bradford B.; Borak, Thomas B.; Guetersloh, Stephen B.; Zeitlin, Cary J.; Miller, J.; Heilbronn, L.; Murakami, T.; Iwata, Y.

2001-09-04

The radiation environment aboard the space shuttle and the International Space Station includes high-Z and high-energy (HZE) particles that are part of the galactic cosmic radiation (GCR) spectrum. Iron-56 is considered to be one of the most biologically important parts of the GCR spectrum. Tissue-equivalent proportional counters (TEPC) are used as active dosimeters on manned space flights. These TEPC's are further used to determine average quality factor for each space mission. A TEPC simulating a 1 micron diameter sphere of tissue was exposed as part of a particle spectrometer to iron-56 at energies from 200-1000 MeV/nucleon. The response of TEPC in terms of frequency-averaged lineal energy, dose-averaged lineal energy, as well as energy deposited at different impact parameters through detector was determined for six different incident energies of iron-56 in this energy range. Calculations determined that charged particle equilibrium was achieved for each of the six experiments. Energy depositions at different impact parameters were calculated using a radial dose distribution model and the results compared to experimental data.

Multiwire proportional counter (lecture by an electromagnetic delay line)

International Nuclear Information System (INIS)

Bruere-Dawson, R.

1989-01-01

For track localisation of ionizing particles with multiwire proportional chamber, an electronic chain including amplifying, shaping and memorizing circuits is required for each wire. In order to lower the cost of this type of detector, an electromagnetic delay line is proposed among various possibilities. In this paper, different coupling modes between chamber and delay line are studied with their respective advantages. The realization of one meter long delay line with a unit delay time of 15 ns per cm is also presented [fr

Signal yields of keV electronic recoils and their discrimination from nuclear recoils in liquid xenon

Science.gov (United States)

Aprile, E.; Aalbers, J.; Agostini, F.; Alfonsi, M.; Amaro, F. D.; Anthony, M.; Arneodo, F.; Barrow, P.; Baudis, L.; Bauermeister, B.; Benabderrahmane, M. L.; Berger, T.; Breur, P. A.; Brown, A.; Brown, E.; Bruenner, S.; Bruno, G.; Budnik, R.; Bütikofer, L.; Calvén, J.; Cardoso, J. M. R.; Cervantes, M.; Cichon, D.; Coderre, D.; Colijn, A. P.; Conrad, J.; Cussonneau, J. P.; Decowski, M. P.; de Perio, P.; di Gangi, P.; di Giovanni, A.; Diglio, S.; Eurin, G.; Fei, J.; Ferella, A. D.; Fieguth, A.; Fulgione, W.; Gallo Rosso, A.; Galloway, M.; Gao, F.; Garbini, M.; Geis, C.; Goetzke, L. W.; Grandi, L.; Greene, Z.; Grignon, C.; Hasterok, C.; Hogenbirk, E.; Howlett, J.; Itay, R.; Kaminsky, B.; Kazama, S.; Kessler, G.; Kish, A.; Landsman, H.; Lang, R. F.; Lellouch, D.; Levinson, L.; Lin, Q.; Lindemann, S.; Lindner, M.; Lombardi, F.; Lopes, J. A. M.; Mahlstedt, J.; Manfredini, A.; Maris, I.; Marrodán Undagoitia, T.; Masbou, J.; Massoli, F. V.; Masson, D.; Mayani, D.; Messina, M.; Micheneau, K.; Molinario, A.; Morâ, K.; Murra, M.; Naganoma, J.; Ni, K.; Oberlack, U.; Pakarha, P.; Pelssers, B.; Persiani, R.; Piastra, F.; Pienaar, J.; Pizzella, V.; Piro, M.-C.; Plante, G.; Priel, N.; Ramírez García, D.; Rauch, L.; Reichard, S.; Reuter, C.; Rizzo, A.; Rupp, N.; Saldanha, R.; Dos Santos, J. M. F.; Sartorelli, G.; Scheibelhut, M.; Schindler, S.; Schreiner, J.; Schumann, M.; Scotto Lavina, L.; Selvi, M.; Shagin, P.; Shockley, E.; Silva, M.; Simgen, H.; Sivers, M. V.; Stein, A.; Thers, D.; Tiseni, A.; Trinchero, G.; Tunnell, C.; Vargas, M.; Wang, H.; Wang, Z.; Wei, Y.; Weinheimer, C.; Wittweg, C.; Wulf, J.; Ye, J.; Zhang, Y.; Zhu, T.; Xenon Collaboration

2018-05-01

We report on the response of liquid xenon to low energy electronic recoils below 15 keV from beta decays of tritium at drift fields of 92 V /cm , 154 V /cm and 366 V /cm using the XENON100 detector. A data-to-simulation fitting method based on Markov Chain Monte Carlo is used to extract the photon yields and recombination fluctuations from the experimental data. The photon yields measured at the two lower fields are in agreement with those from literature; additional measurements at a higher field of 366 V /cm are presented. The electronic and nuclear recoil discrimination as well as its dependence on the drift field and photon detection efficiency are investigated at these low energies. The results provide new measurements in the energy region of interest for dark matter searches using liquid xenon.

First measurement of the ionization yield of nuclear recoils in liquid argon

Energy Technology Data Exchange (ETDEWEB)

Joshi, T. [Univ. of California, Berkeley, CA (United States). Dept. of Nuclear Engineering; Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Sangiorgio, Samuele [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Bernstein, A. [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Foxe, Michael P. [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Pennsylvania State Univ., University Park, PA (United States). Dept. of Mechanical and Nuclear Engineering; Hagmann, Chris [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Jovanovic, Igor [Pennsylvania State Univ., University Park, PA (United States). Dept. of Mechanical and Nuclear Engineering; Kazkaz, K. [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Mozin, Vladimir V. [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Norman, E. B. [Univ. of California, Berkeley, CA (United States). Dept. of Nuclear Engineering; Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Pereverzev, S. V. [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Rebassoo, Finn O. [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Sorensen, Peter F. [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)

2014-05-01

Liquid phase argon has long been used as a target medium for particle detection via scintillation light. Recently there has been considerable interest in direct detection of both hypothetical darkmatter particles and coherent elastic neutrino nucleus scattering. These as-yet unobserved neutral particle interactions are expected to result in a recoiling argon atom O(keV), generally referred to in the literature as a nuclear recoil. This prompts the question of the available electromagnetic signal in a liquid argon detector. In this Letter we report the first measurement of the ionization yield (Qy), detected electrons per unit energy, resulting from nuclear recoils in liquid argon, measured at 6.7 keV. This is also the lowest energy measurement of nuclear recoils in liquid argon.

Karakteristike trzanja elektromagnetskog topa / Recoil characteristics of an electromagnetic rail gun

Directory of Open Access Journals (Sweden)

Zoran B. Ristić

2009-10-01

Full Text Available U radu je razmatrano trzanje elektromagnetskog šinskog topa i upoređeno sa trzanjem konvencionalnog topa sa barutnim punjenjem. Zaključuje se da je kod elektromagnetskog topa trzanje manje nego kod topa sa barutnim punjenjem. Takođe, pokazano je da pri istim uslovima lansiranja upotreba gasne kočnice topa sa barutnim punjenjem može izmeniti karakteristike trzanja i više ih približiti ponašanju elektromagnetskog topa. / In this paper the electromagnetic rail gun recoil is discussed and compared with the recoil of a conventional, propellant gas driven gun. It is shown that, under similar launch conditions, the recoil of an electromagnetic gun is weaker than that of the powder-driven gun. The use of a muzzle brake on a powder-driven gun can alter its recoil characteristics and make its behavior closer to that of the electromagnetic rail gun.

Detector for recoil nuclei stopping in the spark chamber gas

International Nuclear Information System (INIS)

Aleksanyan, A.S.; Asatiani, T.L.; Ivanov, V.I.; Mkrtchyan, G.G.; Pikhtelev, R.N.

1974-01-01

A detector consisting of the combination of a drift and a wide gap spark chambers and designed to detect recoil nuclei stopping in the spark chamber gas is described. It is shown, that by using an appropriate discrimination the detector allows to detect reliably the recoil nuclei in the presence of intensive electron and γ-quanta beams

Sonic Rarefaction Wave Low Recoil Gun

National Research Council Canada - National Science Library

Kathe, E

2002-01-01

A principal challenge faced by the U.S. Army TACOM-ARDEC Benet Laboratories in the design of armaments for lightweight future fighting vehicles with lethality overmatch is mitigating the deleterious effects of large caliber cannon recoil...

Recoil implantation of boron into silicon by high energy silicon ions

Science.gov (United States)

Shao, L.; Lu, X. M.; Wang, X. M.; Rusakova, I.; Mount, G.; Zhang, L. H.; Liu, J. R.; Chu, Wei-Kan

2001-07-01

A recoil implantation technique for shallow junction formation was investigated. After e-gun deposition of a B layer onto Si, 10, 50, or 500 keV Si ion beams were used to introduce surface deposited B atoms into Si by knock-on. It has been shown that recoil implantation with high energy incident ions like 500 keV produces a shallower B profile than lower energy implantation such as 10 keV and 50 keV. This is due to the fact that recoil probability at a given angle is a strong function of the energy of the primary projectile. Boron diffusion was showed to be suppressed in high energy recoil implantation and such suppression became more obvious at higher Si doses. It was suggested that vacancy rich region due to defect imbalance plays the role to suppress B diffusion. Sub-100 nm junction can be formed by this technique with the advantage of high throughput of high energy implanters.

A recoil detector of Koala experiment at HESR

Energy Technology Data Exchange (ETDEWEB)

Xu, Huagen [Forschungszentrum Juelich (Germany)

2015-07-01

The concept of the luminosity detector for the PANDA experiment is based on measuring antiproton-proton elastic scattering in the Coulomb-nuclear interference region by 4 planes of HV-MAPS tracking detectors. The absolute precision is limited by the lack of existing data of the physics quantities σ{sub tot}, ρ and b describing the differential cross section as a function of squared 4-momentum transfer t in the relevant beam momentum region. Therefore, the so-called Koala experiment has been proposed to measure antiproton-proton elastic scattering. The goal of Koala experiment is to measure a wide range of t-distribution to determine the parameters σ{sub tot}, ρ and b. The idea is to measure the scattered beam antiprotons at forward angles by tracking detectors and the recoil target protons near 90 {sup circle} by energy detectors. In order to validate this method a recoil detector has been designed and built. Commissioning of the recoil detector by measuring proton-proton elastic scattering has been performed at COSY. Preliminary results of the commissioning are presented.

Elastic recoil detection analysis of ferroelectric films

Energy Technology Data Exchange (ETDEWEB)

Stannard, W.B.; Johnston, P.N.; Walker, S.R.; Bubb, I.F. [Royal Melbourne Inst. of Tech., VIC (Australia); Scott, J.F. [New South Wales Univ., Kensington, NSW (Australia); Cohen, D.D.; Dytlewski, N. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)

1996-12-31

There has been considerable progress in developing SrBi{sub 2}Ta{sub 2}O{sub 9} (SBT) and Ba{sub O.7}Sr{sub O.3}TiO{sub 3} (BST) ferroelectric films for use as nonvolatile memory chips and for capacitors in dynamic random access memories (DRAMs). Ferroelectric materials have a very large dielectric constant ( {approx} 1000), approximately one hundred times greater than that of silicon dioxide. Devices made from these materials have been known to experience breakdown after a repeated voltage pulsing. It has been suggested that this is related to stoichiometric changes within the material. To accurately characterise these materials Elastic Recoil Detection Analysis (ERDA) is being developed. This technique employs a high energy heavy ion beam to eject nuclei from the target and uses a time of flight and energy dispersive (ToF-E) detector telescope to detect these nuclei. The recoil nuclei carry both energy and mass information which enables the determination of separate energy spectra for individual elements or for small groups of elements In this work ERDA employing 77 MeV {sup 127}I ions has been used to analyse Strontium Bismuth Tantalate thin films at the heavy ion recoil facility at ANSTO, Lucas Heights. 9 refs., 5 figs.

Elastic recoil detection analysis of ferroelectric films

Energy Technology Data Exchange (ETDEWEB)

Stannard, W B; Johnston, P N; Walker, S R; Bubb, I F [Royal Melbourne Inst. of Tech., VIC (Australia); Scott, J F [New South Wales Univ., Kensington, NSW (Australia); Cohen, D D; Dytlewski, N [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)

1997-12-31

There has been considerable progress in developing SrBi{sub 2}Ta{sub 2}O{sub 9} (SBT) and Ba{sub O.7}Sr{sub O.3}TiO{sub 3} (BST) ferroelectric films for use as nonvolatile memory chips and for capacitors in dynamic random access memories (DRAMs). Ferroelectric materials have a very large dielectric constant ( {approx} 1000), approximately one hundred times greater than that of silicon dioxide. Devices made from these materials have been known to experience breakdown after a repeated voltage pulsing. It has been suggested that this is related to stoichiometric changes within the material. To accurately characterise these materials Elastic Recoil Detection Analysis (ERDA) is being developed. This technique employs a high energy heavy ion beam to eject nuclei from the target and uses a time of flight and energy dispersive (ToF-E) detector telescope to detect these nuclei. The recoil nuclei carry both energy and mass information which enables the determination of separate energy spectra for individual elements or for small groups of elements In this work ERDA employing 77 MeV {sup 127}I ions has been used to analyse Strontium Bismuth Tantalate thin films at the heavy ion recoil facility at ANSTO, Lucas Heights. 9 refs., 5 figs.

Penetration of HEPA filters by alpha recoil aerosols

International Nuclear Information System (INIS)

McDowell, W.J.; Seeley, F.G.; Ryan, M.T.

1976-01-01

The self-scattering of alpha-active substances has long been recognized and is attributed to expulsion of aggregates of atoms from the surface of alpha-active materials by alpha emission recoil energy, and perhaps to further propulsion of these aggregates by subsequent alpha recoils. Workers at the University of Lowell recently predicted that this phenomenon might affect the retention of alpha-active particulate matter by HEPA filters, and found support in experiments with 212 Pb. Tests at Oak Ridge National Laboratory have confirmed that alpha-emitting particulate matter does penetrate high-efficiency filter media, such as that used in HEPA filters, much more effectively than do non-radioactive or beta-gamma active aerosols. Filter retention efficiencies drastically lower than the 99.9 percent quoted for ordinary particulate matter were observed with 212 Pb, 253 Es, and 238 Pu sources, indicating that the phenomenon is common to all of these and probably to all alpha-emitting materials of appropriate half-life. Results with controlled air-flow through filters in series are consistent with the picture of small particles dislodged from the ''massive'' surface of an alpha-active material, and then repeatedly dislodged from positions on the filter fibers by subsequent alpha recoils. The process shows only a small dependence on the physical form of the source material. Oxide dust, nitrate salt, and plated metal all seem to generate the recoil particles effectively. The amount penetrating a series of filters depends on the total amount of activity in the source material, its specific activity, and the length of time of air flow

Recoil transporter devices

International Nuclear Information System (INIS)

Madhavan, N.

2005-01-01

The study of sparsely produced nuclear reaction products in the direction of intense primary beam is a challenging task, the pursuit of which has given rise to the advent or several types of selective devices. These range from a simple parallel plate electrostatic deflector to state-of-the-art electromagnetic separators. There is no single device which can satisfy all the requirements of an ideal recoil transporter, simultaneously. An overview of such devices and their building blocks is presented, which may help in the proper choice of the device as per the experimental requirements. (author)

Nuclear reactions excited by recoil protons on a nuclear reactor

International Nuclear Information System (INIS)

Mukhammedov, S.; Khaydarov, A.; Barsukova, E.G.

2006-01-01

The nuclear reactions excited by recoil protons and of the detection possibility of the various chemical elements with the use of these secondary nucleus reactions were investigated. The recoil protons are produced on a nuclear reactor in the result of (n, p) inelastic and elastic scattering interaction of fast neutrons with nuclei of hydrogen. It is well known that the share of fast neutrons in energetic spectrum of reactor's neutrons in comparison with the share of thermal neutrons is small. . Consequently, the share of recoil protons produced in the result of fast neutron interaction with nuclei of light elements, capable to cause the nuclear reactions, is also small, des, due to Coulomb barrier of nuclei the recoil protons can cause the nuclear reactions only on nuclei of light and some middle elements. Our studies show that observable yields have radio nuclides excited in the result of nuclear reactions on Li, B, O, V and Cu. Our experimental results have demonstrated that the proton activation analysis based on the application of secondary nuclear reactions is useful technique to determine large contents of various light and medium chemical elements. Detection limits for studied chemical elements are estimated better than 10 ppm

Investigation of fractional momentum transfer: measurement of forward recoil ranges in 16O + natTm collisions

International Nuclear Information System (INIS)

Singh, Pushpendra P.; Unnati; Sharma, Manoj Kumar; Singh, B.P.; Prasad, R.; Rakesh Kumar; Golda, K.S.; Bhardwaj, H.D.

2006-01-01

For better understanding of complete fusion and incomplete fusion in heavy ion reactions a programme of precise measurements of excitation functions, recoil range distribution and angular distributions of recoils has been undertaken. In the present contribution the recoil range distribution for the residues have been measured at ≅ 6 MeV/nucleon, using recoil-catcher technique followed by off-line gamma-spectroscopy

Measurements of recoil and projectile momentum distributions for 19-MeV F9+ + Ne collisions

International Nuclear Information System (INIS)

Frohne, V.; Cheng, S.; Ali, R.M.; Raphaelian, M.L.; Cocke, C.L.; Olson, R.

1996-01-01

The collision system of 19-MeV F 9+ on Ne has been studied using recoil and projectile momentum spectroscopy. For each event, identified by final recoil and projectile charge state, the three-dimensional momentum vector of the recoil ion and the transverse momentum vector of the projectile ion were measured. The transverse momenta of the recoil and projectile ions were found to be equal in magnitude and opposite in direction, indicating that the transverse momentum exchange is dominated by interactions between the two ion cores. The transverse momentum distributions are well described by nCTMC calculations. The longitudinal momentum distributions of the recoil ions show that a large fraction of the momentum transferred to the projectile is carried off by continuum electrons. The recoil ions are scattered slightly backward, in partial agreement with predictions of nCTMC calculations. copyright 1996 The American Physical Society

Energy and depth resolution in elastic recoil coincidence spectrometry

Energy Technology Data Exchange (ETDEWEB)

Szilagyi, E., E-mail: szilagyi@rmki.kfki.h [KFKI Research Institute for Particle and Nuclear Physics, P.O. Box 49, H-1525 Budapest (Hungary)

2010-06-15

Elastic recoil coincidence spectrometry was implemented into the analytical ion beam simulation program DEPTH. In the calculations, effective detector geometry and multiple scattering effects are considered. Mott's cross section for the identical, spin zero particles is included. Spectra based on the individual detector signal and summing the energy of the recoiled and scattered particles originating from the same scattering events can also be calculated. To calculate this latter case, the dependency of the energy spread contributions had to be reconsidered.

Energy and depth resolution in elastic recoil coincidence spectrometry

International Nuclear Information System (INIS)

Szilagyi, E.

2010-01-01

Elastic recoil coincidence spectrometry was implemented into the analytical ion beam simulation program DEPTH. In the calculations, effective detector geometry and multiple scattering effects are considered. Mott's cross section for the identical, spin zero particles is included. Spectra based on the individual detector signal and summing the energy of the recoiled and scattered particles originating from the same scattering events can also be calculated. To calculate this latter case, the dependency of the energy spread contributions had to be reconsidered.

Exclusive ρ0 production measured with the HERMES recoil detector

International Nuclear Information System (INIS)

Perez Benito, Roberto Francisco

2010-12-01

The Hermes experiment (HERa MEasurement of Spin) at Desy was designed to study the spin structure of the nucleon in semi-inclusive deep inelastic scattering. The internal structure of the nucleon has been investigated in detail and it has been measured that the intrinsic quark spin contribution is only about 30% of the total spin of the nucleon. A formalism to describe the internal structure of the nucleon called Generalised Patron Distributions (GPDs) was developed recently to understand the fundamental structure of the nucleon. These GPDs can be accessed by the measurement of hard exclusive reactions and hard exclusive processes that can be understood in terms of GPDs. The accumulated Hermes data offer access to GPDs in different combinations of beam charge and beam and target helicity asymmetries. To improve exclusivity and to enhance the resolution of kinematic variables to study hard exclusive processes which provide access to the GPDs and hence to the orbital angular momentum of the quarks, in January 2006 a Recoil Detector was installed that surrounded the internal gas target of the Hermes experiment. The Hermes Recoil Detector consisted of three components: a silicon strip detector inside the vacuum, a scintillating fiber tracker and the photon detector. All three detectors were located inside a solenoidal magnet which provided a 1T longitudinal magnetic field. The Recoil Detector improves the selection of exclusive events by a direct measurement of the momentum and track position of the recoiling particle as well as by rejecting non-exclusive background. This detector was an ideal novel tool to combine energy and position measurements for charged particles in a momentum range of 0.1 to 1.4 GeV/c. The Recoil Detector was fully commissioned and operating. Data was taken continuously until the final Hera shutdown in July of 2007. In this thesis we report on the performance of the Recoil Detector and more specifically about the scintillating fiber tracker

Little Boy neutron spectrum below 3 MeV

International Nuclear Information System (INIS)

Evans, A.E.; Bennett, E.F.; Yule, T.J.

1984-01-01

The leakage neutron spectrum from the Little Boy replica has been measured from 12 keV to 3 MeV using a high-resolution 3 He ionization chamber, and from 1 keV to 3 MeV using proton-recoil proportional counters. The 3 He-spectrometer measurements were made at distances of 0.75 and 2.0 m from the active center and at angles of 0 0 , 45 0 , and 90 0 with respect to the axis of the assembly. Proton-recoil measurments were made at 90 0 to the assembly axis at distances of 0.75 and 2.0 m, with a shielded measurement made at 2.0 m to estimate background due to scattering. The 3 He spectrometer was calibrated at Los Alamos using monoenergetic 7 Li(p,n) 7 Be neutrons to generate a family of response functions. The proton-recoil counters were calibrated at Argonne by studying the capture of thermal neutrons by nitrogen in the counters, by observation of the 24-keV neutron resonance in iron, and by relating to the known hydrogen content of the counters. The neutron spectrum from Little Boy was found to be highly structured, with peaks corresponding to minima in the iron total neutron cross section. In particular, influence of the 24-keV iron window was evident in both sets of spectra. The measurements provide information for dosimetry calculations and also a valuable intercomparison of neutron spectrometry using the two different detector types. Spectra measured with both detectors are in essential agreement. 8 references, 7 figures, 2 tables

Subthreshold neutron interrogator for detection of radioactive materials

Science.gov (United States)

Evans, Michael L.; Menlove, Howard O.; Baker, Michael P.

1980-01-01

A device for detecting fissionable material such as uranium in low concentrations by interrogating with photoneutrons at energy levels below 500 keV, and typically about 26 keV. Induced fast neutrons having energies above 500 keV by the interrogated fissionable material are detected by a liquid scintillator or recoil proportional counter which is sensitive to the induced fast neutrons. Since the induced fast neutrons are proportional to the concentration of fissionable material, detection of induced fast neutrons indicate concentration of the fissionable material.

Optimization of Counting Times, Figure of Merit and Mass Thickness for Low-background Alpha/beta Proportional Counter in Sea Water

International Nuclear Information System (INIS)

Pakkong, Pannee; Wongsanit, Sarinya; Tumnoi, Yutthana; Udomsomporn, Suchin

2011-06-01

Full text: The determination of gross alpha and beta activity in environmental aqueous samples can be done by using a low-background alpha/beta proportional counter with multiple detector type (Bert hold LB770). The co precipitate sea water samples were considered for optimal regime of counting time, the minimum detectable activity (MDA), mass thickness of samples (mg/cm-2) and figure of merit (FOM). The result showed that the MDA of the measurements were estimated to be 0.07 Bq/l for gross alpha and 0.05 Bq/l for gross beta at counting time of 100 and 200 minute, respectively. The thickness of samples prepared by coprecipitation technique indicated more parochial range when compared to evaporation to dryness method. In addition, the samples were in the suitable range that can be corrected by the previous self-absorption correction factor (F a ) as 0.0003w 2 -0.0414 w+1.692; where F a is the self-absorption correction factor and w is the weight of the final precipitate in milligrams

Calculations of the response functions of Bonner spheres with a spherical 3He proportional counter using a realistic detector model

International Nuclear Information System (INIS)

Wiegel, B.; Alevra, A.V.; Siebert, B.R.L.

1994-11-01

A realistic geometry model of a Bonner sphere system with a spherical 3 He-filled proportional counter and 12 polyethylene moderating spheres with diameters ranging from 7,62 cm (3'') to 45,72 cm (18'') is introduced. The MCNP Monte Carlo computer code is used to calculate the responses of this Bonner sphere system to monoenergetic neutrons in the energy range between 1 meV to 20 MeV. The relative uncertainties of the responses due to the Monte Carlo calculations are less than 1% for spheres up to 30,48 cm (12'') in diameter and less than 2% for the 15'' and 18'' spheres. Resonances in the carbon cross section are seen as significant structures in the response functions. Additional calculations were made to study the influence of the 3 He number density and the polyethylene mass density on the response as well as the angular dependence of the Bonner sphere system. The calculated responses can be adjusted to a large set of calibration measurements with only a single fit factor common to all sphere diameters and energies. (orig.) [de

Quality control of total alpha and beta activity analysis in water using the Proportional Counter of Gaseous Flux technique; Controle de qualidade das análises de atividades alfa e beta total em água pela técnica do Contador Proporcional de Fluxo Gasoso

Energy Technology Data Exchange (ETDEWEB)

Neto, Alberto P.; Bastos, Thiago M.R.; Santos, Thiago O.; Filho, Crescêncio A.S.; França, Elvis J. de, E-mail: albertopereiran@gmail.com, E-mail: thiagomrbastos@gmail.com, E-mail: thiago_cbufpe@yahoo.com.br, E-mail: candrade@cnen.gov.br, E-mail: ejfranca@cnen.gov.br [Centro Regional de Ciências Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil)

2017-07-01

The analytical capacity of the CRCN (Centro Regional de Ciências Nucleares do Nordeste) for quantification of total alpha and beta concentrations in water samples using the Proportional Counter of Gaseous Flux is presented. To demonstrate the traceability of the results, the National Intercomparison Program (PNI) samples were used, promoted by the Institute of Radioprotection and Dosimetry (IRD) from which the Regional Nuclear Science Center of the Northeast (CRCN-NE) participates since 2011. The results reported to the PNI demonstrate the analytical capacity of the CRCN to detect the emission of alpha and beta radioactivities in water within the potability standards in analytical detection of quantification in radioactivity by the technique of the Proportional Flow Counter.

Neutron measuring instruments for radiation protection

International Nuclear Information System (INIS)

Heinzelmann, M.; Schneider, W.; Hoefert, M.; Kuehn, H.; Jahr, R.; Wagner, S.; Piesch, E.

1979-09-01

The present report deals with selected topics from the field of neutron dosimetry for radiation protection connected with the work of the subcommittee 6802 in the Standards Committee on Radiology (NAR) of the German Standards Institute (DIN). It is a sort of material collection. The topics are: 1. Measurement of the absorbed-energy dose by a) ionization chambers in fields of mixed radiation and b) recoil-proton proportional counting tubes. 2. Measurement of the equivalent dose, neutron monitors, combination methods by a) rem-meters, b) recoil-proton counting tubes, c) recombination method, tissue-equivalent proportional counters, activation methods for high energies in fields of mixed radiation, d) personnel dosimetry by means of ionization chambers and counting tubes, e) dosimetry by means of activation methods, nuclear track films, nonphotographic nuclear track detectors and solid-state dosimeters. (orig./HP) [de

On recoil energy dependent void swelling in pure copper: Theoretical treatment

International Nuclear Information System (INIS)

Golubov, S.I.; Singh, B.N.; Trinkaus, H.

2000-06-01

Over the years, an enormous amount of experimental results have been reported on damage accumulation (e.g. void swelling) in metals and alloys irradiated under vastly different recoil energy conditions. Unfortunately, however, very little is known either experimentally or theoretically about the effect of recoil energy on damage accumulation. Recently, dedicated irradiation experiments using 2.5 MeV electrons, 3.0 MeV protons and fission neutrons have been carried out to determine the effect of recoil energy on the damage accumulation behaviour in pure copper and the results have been reported in Part I of this paper (Singh, Eldrup, Horsewell, Ehrhart and Dworschak 2000). The present paper attempts to provide a theoretical framework within which the effect of recoil energy on damage accumulation behaviour can be understood. The damage accumulation under Frenkel pair production (e.g. 2.5 MeV electron) has been treated in terms of the standard rate theory (SRT) model whereas the evolution of the defect microstructure under cascade damage conditions (e.g. 3.0 MeV protons and fission neutrons) has been calculated within the framework of the production bias model (PBM). Theoretical results, in agreement with experimental results, show that the damage accumulation behaviour is very sensitive to recoil energy and under cascade damage conditions can be treated only within the framework of the PBM. The intracascade clustering of self-interstitial atoms (SIAs) and the properties of SIA clusters such as one-dimensional diffusional transport and thermal stability are found to be the main reasons for the recoil energy dependent vacancy supersaturation. The vacancy supersaturation is the main driving force for the void nucleation and void swelling. In the case of Frenkel pair production, the experimental results are found to be consistent with the SRT model with a dislocation bias value of 2 %. (au)

Measurement of Nuclear Recoils in the CDMS II Dark Matter Search

Energy Technology Data Exchange (ETDEWEB)

Fallows, Scott Mathew [Univ. of Minnesota, Minneapolis, MN (United States)

2014-12-01

The Cryogenic Dark Matter Search (CDMS) experiment is designed to directly detect elastic scatters of weakly-interacting massive dark matter particles (WIMPs), on target nuclei in semiconductor crystals composed of Si and Ge. These scatters would occur very rarely, in an overwhelming background composed primarily of electron recoils from photons and electrons, as well as a smaller but non-negligible background of WIMP-like nuclear recoils from neutrons. The CDMS II generation of detectors simultaneously measure ionization and athermal phonon signals from each scatter, allowing discrimination against virtually all electron recoils in the detector bulk. Pulse-shape timing analysis allows discrimination against nearly all remaining electron recoils taking place near detector surfaces. Along with carefully limited neutron backgrounds, this experimental program allowed for \\background- free" operation of CDMS II at Soudan, with less than one background event expected in each WIMP-search analysis. As a result, exclusionary upper-limits on WIMP-nucleon interaction cross section were placed over a wide range of candidate WIMP masses, ruling out large new regions of parameter space.

Excitation of accelerating plasma waves by counter-propagating laser beams

International Nuclear Information System (INIS)

Shvets, Gennady; Fisch, Nathaniel J.; Pukhov, Alexander

2002-01-01

The conventional approach to exciting high phase velocity waves in plasmas is to employ a laser pulse moving in the direction of the desired particle acceleration. Photon downshifting then causes momentum transfer to the plasma and wave excitation. Novel approaches to plasma wake excitation, colliding-beam accelerator (CBA), which involve photon exchange between the long and short counter-propagating laser beams, are described. Depending on the frequency detuning Δω between beams and duration τ L of the short pulse, there are two approaches to CBA. First approach assumes (τ L ≅2/ω p ). Photons exchanged between the beams deposit their recoil momentum in the plasma driving the plasma wake. Frequency detuning between the beams determines the direction of the photon exchange, thereby controlling the phase of the plasma wake. This phase control can be used for reversing the slippage of the accelerated particles with respect to the wake. A variation on the same theme, super-beatwave accelerator, is also described. In the second approach, a short pulse with τ L >>ω p -1 detuned by Δω∼2ω p from the counter-propagating beam is employed. While parametric excitation of plasma waves by the electromagnetic beatwave at 2ω p of two co-propagating lasers was first predicted by Rosenbluth and Liu [M. N. Rosenbluth and C. S. Liu, Phys. Rev. Lett. 29, 701 (1972)], it is demonstrated that the two excitation beams can be counter-propagating. The advantages of using this geometry (higher instability growth rate, insensitivity to plasma inhomogeneity) are explained, and supporting numerical simulations presented

Synchrotron-radiation experiments with recoil ions

International Nuclear Information System (INIS)

Levin, J.C.

1989-01-01

Studies of atoms, ions and molecules with synchrotron radiation have generally focused on measurements of properties of the electrons ejected during, or after, the photoionization process. Much can also be learned, however, about the atomic or molecular relaxation process by studies of the residual ions or molecular fragments following inner-shell photoionization. Measurements are reported of mean kinetic energies of highly charged argon, krypton, and xenon recoil ions produced by vacancy cascades following inner-shell photoionization using white and monochromatic synchrotron x radiation. Energies are much lower than for the same charge-state ions produced by charged-particle impact. The results may be applicable to design of future angle-resolved ion-atom collision experiments. Photoion charge distributions are presented and compared with other measurements and calculations. Related experiments with synchrotron-radiation produced recoil ion, including photoionization of stored ions and measurement of shakeoff in near-threshold excitation, are briefly discussed. 24 refs., 6 figs., 1 tab

Molecular frame and recoil frame angular distributions in dissociative photoionization of small molecules

International Nuclear Information System (INIS)

Lucchese, R R; Carey, R; Elkharrat, C; Houver, J C; Dowek, D

2008-01-01

Photoelectron angular distributions in the dipole approximation can be written with respect to several different reference frames. A brief review of the molecular frame and recoil frame are given. Experimentally, one approach for obtaining such angular distributions is through angle-resolved coincidence measurements of dissociative ionization. If the system dissociates into two heavy fragments, then the recoil frame angular distribution can be measured. Computed molecular frame and recoil frame photoelectron angular distributions are compared to experimental data for the Cl 2p ionization of CH 3 Cl.

A recoil resilient lumen support, design, fabrication and mechanical evaluation

Science.gov (United States)

Mehdizadeh, Arash; Ali, Mohamed Sultan Mohamed; Takahata, Kenichi; Al-Sarawi, Said; Abbott, Derek

2013-06-01

Stents are artificial implants that provide scaffolding to a cavity inside the body. This paper presents a new luminal device for reducing the mechanical failure of stents due to recoil, which is one of the most important issues in stenting. This device, which we call a recoil-resilient ring (RRR), is utilized standalone or potentially integrated with existing stents to address the problem of recoil. The proposed structure aims to minimize the need for high-pressure overexpansion that can induce intra-luminal trauma and excess growth of vascular tissue causing later restenosis. The RRR is an overlapped open ring with asymmetrical sawtooth structures that are intermeshed. These teeth can slide on top of each other, while the ring is radially expanded, but interlock step-by-step so as to keep the final expanded state against compressional forces that normally cause recoil. The RRRs thus deliver balloon expandability and, when integrated with a stent, bring both radial rigidity and longitudinal flexibility to the stent. The design of the RRR is investigated through finite element analysis (FEA), and then the devices are fabricated using micro-electro-discharge machining of 200-µm-thick Nitinol sheet. The standalone RRR is balloon expandable in vitro by 5-7 Atm in pressure, which is well within the recommended in vivo pressure ranges for stenting procedures. FEA compression tests indicate 13× less reduction of the cross-sectional area of the RRR compared with a typical stainless steel stent. These results also show perfect elastic recovery of the RRR after removal of the pressure compared to the remaining plastic deformations of the stainless steel stent. On the other hand, experimental loading tests show that the fabricated RRRs have 2.8× radial stiffness compared to a two-column section of a commercial stent while exhibiting comparable elastic recovery. Furthermore, testing of in vitro expansion in a mock artery tube shows around 2.9% recoil, approximately 5-11�

A recoil resilient lumen support, design, fabrication and mechanical evaluation

International Nuclear Information System (INIS)

Mehdizadeh, Arash; Al-Sarawi, Said; Abbott, Derek; Ali, Mohamed Sultan Mohamed; Takahata, Kenichi

2013-01-01

Stents are artificial implants that provide scaffolding to a cavity inside the body. This paper presents a new luminal device for reducing the mechanical failure of stents due to recoil, which is one of the most important issues in stenting. This device, which we call a recoil-resilient ring (RRR), is utilized standalone or potentially integrated with existing stents to address the problem of recoil. The proposed structure aims to minimize the need for high-pressure overexpansion that can induce intra-luminal trauma and excess growth of vascular tissue causing later restenosis. The RRR is an overlapped open ring with asymmetrical sawtooth structures that are intermeshed. These teeth can slide on top of each other, while the ring is radially expanded, but interlock step-by-step so as to keep the final expanded state against compressional forces that normally cause recoil. The RRRs thus deliver balloon expandability and, when integrated with a stent, bring both radial rigidity and longitudinal flexibility to the stent. The design of the RRR is investigated through finite element analysis (FEA), and then the devices are fabricated using micro-electro-discharge machining of 200-µm-thick Nitinol sheet. The standalone RRR is balloon expandable in vitro by 5–7 Atm in pressure, which is well within the recommended in vivo pressure ranges for stenting procedures. FEA compression tests indicate 13× less reduction of the cross-sectional area of the RRR compared with a typical stainless steel stent. These results also show perfect elastic recovery of the RRR after removal of the pressure compared to the remaining plastic deformations of the stainless steel stent. On the other hand, experimental loading tests show that the fabricated RRRs have 2.8× radial stiffness compared to a two-column section of a commercial stent while exhibiting comparable elastic recovery. Furthermore, testing of in vitro expansion in a mock artery tube shows around 2.9% recoil, approximately 5�

Recoiling Black Holes: Electromagnetic Signatures, Candidates, and Astrophysical Implications

Directory of Open Access Journals (Sweden)

S. Komossa

2012-01-01

Full Text Available Supermassive black holes (SMBHs may not always reside right at the centers of their host galaxies. This is a prediction of numerical relativity simulations, which imply that the newly formed single SMBH, after binary coalescence in a galaxy merger, can receive kick velocities up to several 1000 km/s due to anisotropic emission of gravitational waves. Long-lived oscillations of the SMBHs in galaxy cores, and in rare cases even SMBH ejections from their host galaxies, are the consequence. Observationally, accreting recoiling SMBHs would appear as quasars spatially and/or kinematically offset from their host galaxies. The presence of the “kicks” has a wide range of astrophysical implications which only now are beginning to be explored, including consequences for black hole and galaxy assembly at the epoch of structure formation, black hole feeding, and unified models of active galactic nuclei (AGN. Here, we review the observational signatures of recoiling SMBHs and the properties of the first candidates which have emerged, including follow-up studies of the candidate recoiling SMBH of SDSSJ092712.65+294344.0.

Limitations to depth resolution in high-energy, heavy-ion elastic recoil detection analysis

International Nuclear Information System (INIS)

Elliman, R.G.; Palmer, G.R.; Ophel, T.R.; Timmers, H.

1998-01-01

The depth resolution of heavy-ion elastic recoil detection analysis was examined for Al and Co thin films ranging in thickness from 100 to 400 nm. Measurements were performed with 154 MeV Au ions as the incident beam, and recoils were detected using a gas ionisation detector. Energy spectra were extracted for the Al and Co recoils and the depth resolution determined as a function of film thickness from the width of the high- and low- energy edges. These results were compared with theoretical estimates calculated using the computer program DEPTH. (authors)

Elastic recoil detection analysis of hydrogen in polymers

Energy Technology Data Exchange (ETDEWEB)

Winzell, T.R.H.; Whitlow, H.J. [Lund Univ. (Sweden); Bubb, I.F.; Short, R.; Johnston, P.N. [Royal Melbourne Inst. of Tech., VIC (Australia)

1996-12-31

Elastic recoil detection analysis (ERDA) of hydrogen in thick polymeric films has been performed using 2.5 MeV He{sup 2+} ions from the tandem accelerator at the Royal Melbourne Institute of Technology. The technique enables the use of the same equipment as in Rutherford backscattering analysis, but instead of detecting the incident backscattered ion, the lighter recoiled ion is detected at a small forward angle. The purpose of this work is to investigate how selected polymers react when irradiated by helium ions. The polymers are to be evaluated for their suitability as reference standards for hydrogen depth profiling. Films investigated were Du Pont`s Kapton and Mylar, and polystyrene. 11 refs., 3 figs.

Elastic recoil detection analysis of hydrogen in polymers

Energy Technology Data Exchange (ETDEWEB)

Winzell, T R.H.; Whitlow, H J [Lund Univ. (Sweden); Bubb, I F; Short, R; Johnston, P N [Royal Melbourne Inst. of Tech., VIC (Australia)

1997-12-31

Elastic recoil detection analysis (ERDA) of hydrogen in thick polymeric films has been performed using 2.5 MeV He{sup 2+} ions from the tandem accelerator at the Royal Melbourne Institute of Technology. The technique enables the use of the same equipment as in Rutherford backscattering analysis, but instead of detecting the incident backscattered ion, the lighter recoiled ion is detected at a small forward angle. The purpose of this work is to investigate how selected polymers react when irradiated by helium ions. The polymers are to be evaluated for their suitability as reference standards for hydrogen depth profiling. Films investigated were Du Pont`s Kapton and Mylar, and polystyrene. 11 refs., 3 figs.

Multivariate techniques of analysis for ToF-E recoil spectrometry data

Energy Technology Data Exchange (ETDEWEB)

Whitlow, H.J.; Bouanani, M.E.; Persson, L.; Hult, M.; Jonsson, P.; Johnston, P.N. [Lund Institute of Technology, Solvegatan, (Sweden), Department of Nuclear Physics; Andersson, M. [Uppsala Univ. (Sweden). Dept. of Organic Chemistry; Ostling, M.; Zaring, C. [Royal institute of Technology, Electrum, Kista, (Sweden), Department of Electronics; Johnston, P.N.; Bubb, I.F.; Walker, B.R.; Stannard, W.B. [Royal Melbourne Inst. of Tech., VIC (Australia); Cohen, D.D.; Dytlewski, N. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)

1996-12-31

Multivariate statistical methods are being developed by the Australian -Swedish Recoil Spectrometry Collaboration for quantitative analysis of the wealth of information in Time of Flight (ToF) and energy dispersive Recoil Spectrometry. An overview is presented of progress made in the use of multivariate techniques for energy calibration, separation of mass-overlapped signals and simulation of ToF-E data. 6 refs., 5 figs.

Multivariate techniques of analysis for ToF-E recoil spectrometry data

Energy Technology Data Exchange (ETDEWEB)

Whitlow, H J; Bouanani, M E; Persson, L; Hult, M; Jonsson, P; Johnston, P N [Lund Institute of Technology, Solvegatan, (Sweden), Department of Nuclear Physics; Andersson, M [Uppsala Univ. (Sweden). Dept. of Organic Chemistry; Ostling, M; Zaring, C [Royal institute of Technology, Electrum, Kista, (Sweden), Department of Electronics; Johnston, P N; Bubb, I F; Walker, B R; Stannard, W B [Royal Melbourne Inst. of Tech., VIC (Australia); Cohen, D D; Dytlewski, N [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)

1997-12-31

Multivariate statistical methods are being developed by the Australian -Swedish Recoil Spectrometry Collaboration for quantitative analysis of the wealth of information in Time of Flight (ToF) and energy dispersive Recoil Spectrometry. An overview is presented of progress made in the use of multivariate techniques for energy calibration, separation of mass-overlapped signals and simulation of ToF-E data. 6 refs., 5 figs.

A new recoil filter for {gamma}-detector arrays

Energy Technology Data Exchange (ETDEWEB)

Heese, J; Lahmer, W; Maier, K H [Hahn-Meitner-Institut Berlin GmbH (Germany); Janicki, M; Meczynski, W; Styczen, J [Institute of Nuclear Physics, Cracow (Poland)

1992-08-01

A considerable improvement of gamma spectra recorded in heavy ion induced fusion evaporation residues can be achieved when gamma rays are detected in coincidence with the recoiling evaporations residues. This coincidence suppresses gamma rays from fission processes, Coulombic excitation, and reactions with target contaminations, and therefore cleans gamma spectra and improves the peak to background ratio. A sturdy detector for evaporation residues has been designed as an additional detector for the OSIRIS spectrometer. The recoil filter consists of two rings of six and twelve detector elements. In each detector element, nuclei hitting a thin Mylar foil produce secondary electrons, which are electrostatically accelerated and focussed onto a thin plastic scintillator. Recoiling evaporation residues are discriminated from other reaction products and scattered beam by the pulse height of the scintillation signal and time of flight. The detector signal is fast enough to allow the detection of an evaporation residue even if the scattered beam hits the detector first. In-beam experiment were performed with the reactions {sup 40}Ar+{sup 124}Sn, {sup 40}Ar+{sup 152}Sm at 185 MeV beam energy, and {sup 36}Ar+{sup 154,156}Gd at 175 MeV. In the latter two cases, fission amount to 50-75% of the total fusion cross section. 10 refs., 4 figs.

Gravitational recoil from binary black hole mergers: The close-limit approximation

International Nuclear Information System (INIS)

Sopuerta, Carlos F.; Yunes, Nicolas; Laguna, Pablo

2006-01-01

The coalescence of a binary black hole system is one of the main sources of gravitational waves that present and future detectors will study. Apart from the energy and angular momentum that these waves carry, for unequal-mass binaries there is also a net flux of linear momentum that implies a recoil velocity of the resulting final black hole in the opposite direction. Due to the relevance of this phenomenon in astrophysics, in particular, for galaxy merger scenarios, there have been several attempts to estimate the magnitude of this velocity. Since the main contribution to the recoil comes from the last orbit and plunge, an approximation valid at the last stage of coalescence is well motivated for this type of calculation. In this paper, we present a computation of the recoil velocity based on the close-limit approximation scheme, which gives excellent results for head-on and grazing collisions of black holes when compared to full numerical relativistic calculations. We obtain a maximum recoil velocity of ∼57 km/s for a symmetric mass ratio η=M 1 M 2 /(M 1 +M 2 ) 2 ∼0.19 and an initial proper separation of 4M, where M is the total Arnowitt-Deser-Misner (ADM) mass of the system. This separation is the maximum at which the close-limit approximation is expected to provide accurate results. Therefore, it cannot account for the contributions due to inspiral and initial merger. If we supplement this estimate with post-Newtonian (PN) calculations up to the innermost stable circular orbit, we obtain a lower bound for the recoil velocity, with a maximum around 80 km/s. This is a lower bound because it neglects the initial merger phase. We can however obtain a rough estimate by using PN methods or the close-limit approximation. Since both methods are known to overestimate the amount of radiation, we obtain in this way an upper bound for the recoil with maxima in the range of 214-240 km/s. We also provide nonlinear fits to these estimated upper and lower bounds. These

Exclusive {rho}{sup 0} production measured with the HERMES recoil detector

Energy Technology Data Exchange (ETDEWEB)

Perez Benito, Roberto Francisco

2010-12-15

The Hermes experiment (HERa MEasurement of Spin) at Desy was designed to study the spin structure of the nucleon in semi-inclusive deep inelastic scattering. The internal structure of the nucleon has been investigated in detail and it has been measured that the intrinsic quark spin contribution is only about 30% of the total spin of the nucleon. A formalism to describe the internal structure of the nucleon called Generalised Patron Distributions (GPDs) was developed recently to understand the fundamental structure of the nucleon. These GPDs can be accessed by the measurement of hard exclusive reactions and hard exclusive processes that can be understood in terms of GPDs. The accumulated Hermes data offer access to GPDs in different combinations of beam charge and beam and target helicity asymmetries. To improve exclusivity and to enhance the resolution of kinematic variables to study hard exclusive processes which provide access to the GPDs and hence to the orbital angular momentum of the quarks, in January 2006 a Recoil Detector was installed that surrounded the internal gas target of the Hermes experiment. The Hermes Recoil Detector consisted of three components: a silicon strip detector inside the vacuum, a scintillating fiber tracker and the photon detector. All three detectors were located inside a solenoidal magnet which provided a 1T longitudinal magnetic field. The Recoil Detector improves the selection of exclusive events by a direct measurement of the momentum and track position of the recoiling particle as well as by rejecting non-exclusive background. This detector was an ideal novel tool to combine energy and position measurements for charged particles in a momentum range of 0.1 to 1.4 GeV/c. The Recoil Detector was fully commissioned and operating. Data was taken continuously until the final Hera shutdown in July of 2007. In this thesis we report on the performance of the Recoil Detector and more specifically about the scintillating fiber tracker

Recoiling D-branes

International Nuclear Information System (INIS)

Nakamura, Shin

2005-01-01

We propose a new method to describe a recoiling D-brane that is elastically scattered by closed strings in the nonrelativistic region. We utilize the low-energy effective field theory on the worldvolume of the D-brane, and the velocity of the D-brane is described by the time derivative of the expectation values of the massless scalar fields on the worldvolume. The effects of the closed strings are represented by a source term for the massless fields in this method. The momentum conservation condition between the closed strings and the D-brane is derived up to the relative sign of the momentum of the D-brane

A gas proportional scintillation counter for use in large area detector systems without photomultipliers

International Nuclear Information System (INIS)

Baruch, J.E.F.; Brooke, G.; Kellermann, E.W.; Bateman, J.E.; Connolly, J.F.

1978-03-01

The properties of a prototype gas proportional scintillation detector, for use in large numbers, are examined. The detector is designed to focus a light signal, which is proportional to ionisation loss, into a fibre optic lightguide. It is shown that a single charged particle traversing the detector produces enough light out of the lightguide to be seen by a TV camera. Problems of lifetime and large scale detector production are discussed. Properties of saturation, linearity, position sensitivity, and operating limits are examined. It is shown that an array of gas proportional scintillation detectors when used with fibre optic lightguides and TV camera readout could offer significant improvements in cost per area and reliability over a scintillator plus photomultiplier or a wire proportional chamber array. (author)

Remote recoil: a new wave mean interaction effect

Science.gov (United States)

Bühler, Oliver; McIntyre, Michael E.

2003-10-01

We present a theoretical study of a fundamentally new wave mean or wave vortex interaction effect able to force persistent, cumulative change in mean flows in the absence of wave breaking or other kinds of wave dissipation. It is associated with the refraction of non-dissipating waves by inhomogeneous mean (vortical) flows. The effect is studied in detail in the simplest relevant model, the two-dimensional compressible flow equations with a generic polytropic equation of state. This includes the usual shallow-water equations as a special case. The refraction of a narrow, slowly varying wavetrain of small-amplitude gravity or sound waves obliquely incident on a single weak (low Froude or Mach number) vortex is studied in detail. It is shown that, concomitant with the changes in the waves' pseudomomentum due to the refraction, there is an equal and opposite recoil force that is felt, in effect, by the vortex core. This effective force is called a ‘remote recoil’ to stress that there is no need for the vortex core and wavetrain to overlap in physical space. There is an accompanying ‘far-field recoil’ that is still more remote, as in classical vortex-impulse problems. The remote-recoil effects are studied perturbatively using the wave amplitude and vortex weakness as small parameters. The nature of the remote recoil is demonstrated in various set-ups with wavetrains of finite or infinite length. The effective recoil force {bm R}_V on the vortex core is given by an expression resembling the classical Magnus force felt by moving cylinders with circulation. In the case of wavetrains of infinite length, an explicit formula for the scattering angle theta_* of waves passing a vortex at a distance is derived correct to second order in Froude or Mach number. To this order {bm R}_V {~} theta_*. The formula is cross-checked against numerical integrations of the ray-tracing equations. This work is part of an ongoing study of internal-gravity-wave dynamics in the

Heavy ion recoil spectrometry of SixGe1-x thin films

International Nuclear Information System (INIS)

Walker, S.R.; Johnston, P.N.; Bubb, I.F.; Cohen, D.D.; Dytlewski, N.; Hult, M.; Whitlow, H.J.; Zaring, C.; Oestling, M.

1993-01-01

Mass and energy dispersive recoil spectrometry employing 77 MeV 127 I ions from ANTARES (FN Tandem) facility at Lucas Heights has been used to examine the isotopic composition of samples of Si x Ge 1-x grown at the Australian National University by Electron Beam Evaporation (EBE). The recoiling target nuclei were analysed by a Time Of Flight and Energy (TOF-E) detector telescope composed of two timing pickoff detectors and a surface barrier (energy) detector. From the time of flight and energy, the ion mass can be determined and individual depth distributions for each element can be obtained. Recoil spectrometry has shown the presence of oxygen in the Si x Ge 1-x layer and has enabled the separate determination of energy spectra for individual elements. 9 refs., 3 figs

Introduction to Neutron Coincidence Counter Design Based on Boron-10

Energy Technology Data Exchange (ETDEWEB)

Kouzes, Richard T.; Ely, James H.; Lintereur, Azaree T.; Siciliano, Edward R.

2012-01-22

The Department of Energy Office of Nonproliferation Policy (NA-241) is supporting the project 'Coincidence Counting With Boron-Based Alternative Neutron Detection Technology' at Pacific Northwest National Laboratory (PNNL) for development of an alternative neutron coincidence counter. The goal of this project is ultimately to design, build and demonstrate a boron-lined proportional tube based alternative system in the configuration of a coincidence counter. This report, providing background information for this project, is the deliverable under Task 1 of the project.

Dead zone characteristics of a gas counter

International Nuclear Information System (INIS)

Nohtomi, Akihiro; Sakae, Takeji; Matoba, Masaru; Koori, Norihiko.

1990-01-01

The dead zone was recently defined as the product of dead length and dead time in order to describe the characteristics of the self-quenching streamer (SQS) mode of a gas counter. Investigation of the dead zone characteristics has been extended for the proportional and GM modes, and the measured dead zone has been compared with that of the SQS mode. Accurate values for the dead zone could be determined by means of a newly developed method with a pulse interval time to amplitude converter. Each operation mode indicates distinct dead zone characteristics. Properties of gas counters for high counting rates may be improved on the basis of measurements of the dead zone. (author)

Recoil 18F-chemistry in fluoroalkanes

International Nuclear Information System (INIS)

Linde, K.D. van der.

1982-01-01

This thesis describes the study of the chemical reactions of recoil 18 F-atoms in gaseous fluoromethanes and fluoroethanes. A brief survey of the organic hot atom chemistry is given in Chapter I. Chapter II deals with the experimental procedures used in this investigation. The irradiation facilities, the vapour phase radio-chromatography and the identification, including the synthesis of some fluorocarbons, are described in detail. Chapter III consists of a study on the applicability of perfluoropropene, C 3 F 6 , as scavenger for thermal 18 F-atoms and radicals. Chapters IV, V, VI and VII deal with 18 F-recoil chemistry in gaseous fluoroethanes, using H 2 S as scavenger. Chapter VIII is a short discussion on the hot 18 F-atom based production of 18 F-labeled organic compounds via decay of the intermediate 18 Ne. A target system is proposed for production of this isotope in high energy and ultra high flux particle beams, which possibly would become available in fast breeders and fusion reactors. (Auth.)

Measurements of the ballistic-phonon component resulting from nuclear and electron recoils in crystalline silicon

International Nuclear Information System (INIS)

Lee, A.T.; Cabrera, B.; Dougherty, B.L.; Penn, M.J.; Pronko, J.G.; Tamura, S.

1996-01-01

We present measurements of the ballistic-phonon component resulting from nuclear and electron recoils in silicon at ∼380 mK. The detectors used for these experiments consist of a 300-μm-thick monocrystal of silicon instrumented with superconducting titanium transition-edge sensors. These sensors detect the initial wavefront of athermal phonons and give a pulse height that is sensitive to changes in surface-energy density resulting from the focusing of ballistic phonons. Nuclear recoils were generated by neutron bombardment of the detector. A Van de Graaff proton accelerator and a thick 7 Li target were used. Pulse-height spectra were compared for neutron, x-ray, and γ-ray events. A previous analysis of this data set found evidence for an increase in the ballistic-phonon component for nuclear recoils compared to electron recoils at a 95% confidence level. An improved understanding of the detector response has led to a change in the result. In the present analysis, the data are consistent with no increase at the 68% confidence level. This change stems from an increase in the uncertainty of the result rather than a significant change in the central value. The increase in ballistic phonon energy for nuclear recoils compared to electron recoils as a fraction of the total phonon energy (for equal total phonon energy events) was found to be 0.024 +0.041 -0.055 (68% confidence level). This result sets a limit of 11.6% (95% confidence level) on the ballistic phonon enhancement for nuclear recoils predicted by open-quote open-quote hot spot close-quote close-quote and electron-hole droplet models, which is the most stringent to date. To measure the ballistic-phonon component resulting from electron recoils, the pulse height as a function of event depth was compared to that of phonon simulations. (Abstract Truncated)

In-beam electron spectrometer used in conjunction with a gas-filled recoil separator

International Nuclear Information System (INIS)

Kankaanpaeae, H.; Butler, P.A.; Greenlees, P.T.; Bastin, J.E.; Herzberg, R.D.; Humphreys, R.D.; Jones, G.D.; Jones, P.; Julin, R.; Keenan, A.; Kettunen, H.; Leino, M.; Miettinen, L.; Page, T.; Rahkila, P.; Scholey, C.; Uusitalo, J.

2004-01-01

The conversion-electron spectrometer SACRED has been redesigned for use in conjunction with the RITU gas-filled recoil separator. The system allows in-beam recoil-decay-tagging (RDT) measurements of internal conversion electrons. The performance of the system using standard sources and in-beam is described

New developments of the recoil distance doppler-shift method

Energy Technology Data Exchange (ETDEWEB)

Fransen, Christoph; Blazhev, Andrey; Braunroth, Thomas; Dewald, Alfred; Goldkuhle, Alina; Jolie, Jan; Litzinger, Julia; Mueller-Gatermann, Claus; Woelk, Dorothea; Zell, Karl-Oskar [Institut fuer Kernphysik, Universitaet zu Koeln (Germany)

2016-07-01

The recoil distance Doppler-shift (RDDS) method is a very valuable technique for measuring lifetimes of excited nuclear states in the picosecond range to deduce absolute transition strengths between nuclear excitations independent on the reaction mechanism. Dedicated plunger devices were built by our group for measurements with this method for a broad range of beam energies ranging from few MeV/u up to relativistic energies of the order of 100 MeV/u. Those were designed to match the constraints defined by state-of-the art γ-ray spectrometers like AGATA, Galileo, Gammasphere. Here we give an overview about recent experiments of our group to determine transition strengths from level lifetimes in exotic nuclei where also recoil separators or mass spectrographs were used for an identification of the recoiling reaction products. The aim is to learn about phenomena like shape phase coexistence in exotic regions and the evolution of the shell structure far from the valley of stability. We also review new plunger devices that are developed by our group for future experimental campaigns with stable and radioactive beams in different energy regimes, e.g., a plunger for HIE-ISOLDE.

Counter-diffusion and -permeation of deuterium and hydrogen through metals

Energy Technology Data Exchange (ETDEWEB)

Kizu, Kaname; Tanabe,; Tetsuo, [Nagoya Univ. (Japan)

1998-03-01

The first experiments for counter-diffusion and -permeation of deuterium and hydrogen through palladium were performed. Deuterium permeation rates against D{sub 2} pressure were measured under the condition where hydrogen permeated to opposite direction by supplying H{sub 2} gas at the permeated side of D{sub 2}. It was found that not a small amount of deuterium was clearly permeated even if the deuterium pressure was much smaller than the hydrogen pressure. Deuterium permeation rate was gradually reduced by increasing the counter H permeation. The deuterium permeation rate under the counter H permeation is well represented by a simple model in which the ratio of the deuterium permeation rates with and without the counter H permeation was proportional to the fractional concentration of deuterium in the bulk. As increasing the hydrogen counter flow, however, the deuterium permeation rate deviates from the model. This means that adsorption (absorption) of D{sub 2} from gas phase is inhibited and surface recombination of deuterium is blocked by hydrogen. (author)

Thermal annealing of recoil 56Mn in strontium permanganate under (n,γ) process

International Nuclear Information System (INIS)

Mishra, Shuddhodan P.; Vijaya

2002-01-01

Chemical stabilization of recoil 56 Mn in strontium permanganate (hydrous and anhydrous) has been investigated with a special reference to pre-and post-activation thermal annealing treatments. The retention of 56 Mn in neutron irradiated strontium permanganate showed significant variation on thermal annealing in both pre-and post-activation heated target. The recoil re-entry process obeys simple first order kinetics and the activation energy deduced for thermal annealing process is very low as computed by classical Arrhenius plots. The results observed are discussed in the light of existing ideas for understanding the recoil stabilization mechanism of parent reformation and the nature of precursors in permanganates. (author)

A new neutron counter for fission research

Energy Technology Data Exchange (ETDEWEB)

Laurent, B., E-mail: benoit.laurent@cea.fr [CEA, DAM, DIF, F-91297 Arpajon (France); Granier, T.; Bélier, G.; Chatillon, A.; Martin, J.-F.; Taieb, J. [CEA, DAM, DIF, F-91297 Arpajon (France); Hambsch, F.-J. [EC-JRC Institute for Reference Materials and Measurements (IRMM), Retieseweg, 2440 Geel (Belgium); Tovesson, F.; Laptev, A.B.; Haight, R.C.; Nelson, R.O.; O' Donnell, J.M. [Los Alamos Neutron Science Center, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

2014-05-01

A new neutron counter for research experiments on nuclear fission has been developed. This instrument is designed for the detection of prompt fission neutrons within relatively high levels of gamma and neutron background. It is composed of a set of {sup 3}He proportional counters arranged within a block of polyethylene which serves as moderator. The detection properties have been studied by means of Monte Carlo simulations and experiments with radioactive sources. These properties are confirmed by an experiment on neutron-induced fission of {sup 238}U at the WNR facility of the Los Alamos Neutron Science Center during which the mean prompt fission neutron multiplicity, or ν{sup ¯} has been measured from 1 to 20 MeV of incident neutron energy.

INS gas-filled recoil isotope separator

International Nuclear Information System (INIS)

Miyatake, M.; Nomura, T.; Kawakami, H.

1986-09-01

The characteristics and performance of a small sized gas-filled recoil isotope separator recently made at INS are described. The total efficiency and the ΔBρ/Bρ values have been measured using low velocity 16 O, 40 Ar and 68 As ions and found to be 10 and 5 %, respectively. The Z-dependence of the mean charge is discussed. (author)

Recoil-ion momentum spectroscopy

International Nuclear Information System (INIS)

Ullrich, J.; Moshammer, R.; Doerner, R.; Jagutzki, O.; Mergel, V.; Schmidt-Boecking, H.; Spielberger, L.

1996-10-01

High-resolution recoil-ion momentum spectroscopy (RIMS) is a novel technique to determine the charge state and the complete final momentum vector P R of a recoiling target ion emerging from an ionising collision of an atom with any kind of radiation. It offers a unique combination of superior momentum resolution in all three spatial directions of ΔP R = 0.07 a.u. with a large detection solid angle of ΔΩ R /4π≥ 98%. Recently, low-energy electron analysers based on rigorously new concepts and reaching similar specifications were successfully integrated into RIM spectrometers yielding so-called ''reaction microscopes''. Exploiting these techniques, a large variety of atomic reactions for ion, electron, photon and antiproton impact have been explored in unprecedented detail and completeness. Among them first kinematically complete experiments on electron capture, single and double ionisation in ion-atom collisions at projectile energies between 5 keV and 1.4 GeV. Double photoionisation of He has been investigated at energies E γ close to the threshold (E γ = 80 eV) up to E γ = 58 keV. At E γ >8 keV the contributions to double ionisation after photoabsorption and Compton scattering were kinematically separated for the first time. These and many other results will be reviewed in this article. In addition, the experimental technique is described in some detail and emphasis is given to envisage the rich future potential of the method in various fields of atomic collision physics with atoms, molecules and clusters. (orig.)

Recoil detector test for the day-one experiment at HESR

Energy Technology Data Exchange (ETDEWEB)

Hu, Qiang [Institute of Modern Physics, CAS, 730000 Lanzhou (China); Forschungszentrum Juelich, 52425 Juelich (Germany); Xu, Huagen; Ritman, James [Forschungszentrum Juelich, 52425 Juelich (Germany)

2013-07-01

The proposed day-one experiment at HESR is a dedicated measurement of antiproton-proton elastic scattering. The aim of the day-one experiment is to determine the elastic differential parameters (total cross section σ{sub T}, the ratio of real to imaginary part of the forward scattering amplitude ρ, and the slope parameter B) by measuring a large range of 4-momentum transfer squared t (0.0008-0.1 GeV{sup 2}). The conceptual design of the day-one experiment is to measure the elastic scattered antiproton and recoil proton, by a tracking detector in the small polar angle range and by an energy detector near 90 , respectively. The recoil arm covers a maximum polar angle range from 71 to 90 and consists of two silicon strip detectors (76.8(length) x 50.0(width) x 1.0(thickness) mm{sup 3}) and two germanium detectors (80.4(length) x 50.0(width) x 5.0 (11.0) (thickness) mm{sup 3}). All detectors are single sided structure with 1.2 mm pitch. The silicon detectors will be used to detect recoil protons with energy up to about 12 MeV and the germanium detectors will be used to detect protons with energy from 12 MeV to 60 MeV. At present, one recoil arm is being constructed and the test for the detectors with radioactive sources is on-going. Preliminary test results indicate that all detectors are operational and work properly. The latest test results of these detectors are presented.

Nuclear recoil scintillation and ionisation yields in liquid xenon from ZEPLIN-III data

Energy Technology Data Exchange (ETDEWEB)

Horn, M., E-mail: m.horn@imperial.ac.uk [High Energy Physics group, Blackett Laboratory, Imperial College London (United Kingdom); Belov, V.A.; Akimov, D.Yu. [Institute for Theoretical and Experimental Physics, Moscow (Russian Federation); Araujo, H.M. [High Energy Physics group, Blackett Laboratory, Imperial College London (United Kingdom); Barnes, E.J. [School of Physics and Astronomy, SUPA University of Edinburgh (United Kingdom); Burenkov, A.A. [Institute for Theoretical and Experimental Physics, Moscow (Russian Federation); Chepel, V. [LIP-Coimbra and Department of Physics of the University of Coimbra (Portugal); Currie, A. [High Energy Physics group, Blackett Laboratory, Imperial College London (United Kingdom); Edwards, B. [Particle Physics Department, STFC Rutherford Appleton Laboratory, Chilton (United Kingdom); Ghag, C.; Hollingsworth, A. [School of Physics and Astronomy, SUPA University of Edinburgh (United Kingdom); Kalmus, G.E. [Particle Physics Department, STFC Rutherford Appleton Laboratory, Chilton (United Kingdom); Kobyakin, A.S.; Kovalenko, A.G. [Institute for Theoretical and Experimental Physics, Moscow (Russian Federation); Lebedenko, V.N. [High Energy Physics group, Blackett Laboratory, Imperial College London (United Kingdom); Lindote, A. [LIP-Coimbra and Department of Physics of the University of Coimbra (Portugal); Particle Physics Department, STFC Rutherford Appleton Laboratory, Chilton (United Kingdom); Lopes, M.I. [LIP-Coimbra and Department of Physics of the University of Coimbra (Portugal); Luescher, R.; Majewski, P. [Particle Physics Department, STFC Rutherford Appleton Laboratory, Chilton (United Kingdom); Murphy, A.StJ. [School of Physics and Astronomy, SUPA University of Edinburgh (United Kingdom)

2011-11-24

Scintillation and ionisation yields for nuclear recoils in liquid xenon above 10 keV{sub nr} (nuclear recoil energy) are deduced from data acquired using broadband Am-Be neutron sources. The nuclear recoil data from several exposures to two sources were compared to detailed simulations. Energy-dependent scintillation and ionisation yields giving acceptable fits to the data were derived. Efficiency and resolution effects are treated using a light collection Monte Carlo, measured photomultiplier response profiles and hardware trigger studies. A gradual fall in scintillation yield below {approx}40 keV{sub nr} is found, together with a rising ionisation yield; both are in agreement with the latest independent measurements. The analysis method is applied to the most recent ZEPLIN-III data, acquired with a significantly upgraded detector and a precision-calibrated Am-Be source, as well as to the earlier data from the first run in 2008. A new method for deriving the recoil scintillation yield, which includes sub-threshold S1 events, is also presented which confirms the main analysis.

Laterally and longitudinally dispersive recoil mass separators

International Nuclear Information System (INIS)

Wollnik, H.

1987-01-01

Principles of laterally dispersive and time-of-flight mass separators are outlined. Special emphasis is given to separators for very energetic recoils for which electrostatic fields would be technologically impossible. The principle of energy isochronous time-of-flight mass separators is shown to be applicable to storage rings. (orig.)

The recoil proton polarization in πp elastic scattering

International Nuclear Information System (INIS)

Seftor, C.J.

1988-09-01

The polarization of the recoil proton for π + p and π - p elastic scattering has been measured for various angles at 547 MeV/c and 625 MeV/c by a collaboration involving The George Washington University; the University of California, Los Angeles; and Abilene Christian University. The experiment was performed at the P 3 East experimental area of the Los Alamos Meson Physics Facility. Beam intensities varied from 0.4 to 1.0 x 10 7 π - 's/sec and from 3.0 to 10.0 x 10 7 π + 's/sec. The beam spot size at the target was 1 cm in the horizontal direction by 2.5 cm in the vertical direction. A liquid-hydrogen target was used in a flask 5.7 cm in diameter and 10 cm high. The scattered pion and recoil proton were detected in coincidence using the Large Acceptance Spectrometer (LAS) to detect and momentum analyze the pions and the JANUS recoil proton polarimeter to detect and measure the polarization of the protons. Results from this experiment are compared with previous measurements of the polarization, with analyzing power data previously taken by this group, and to partial-wave analysis predictions. 12 refs., 53 figs., 18 tabs

Recoil distance lifetime measurements in 122,124Xe

Science.gov (United States)

Govil, I. M.; Kumar, A.; Iyer, H.; Li, H.; Garg, U.; Ghugre, S. S.; Johnson, T.; Kaczarowski, R.; Kharraja, B.; Naguleswaran, S.; Walpe, J. C.

1998-02-01

Lifetimes of the lower-excited states in 122,124Xe are measured using the recoil-distance Doppler-shift technique. The reactions 110Pd(16O,4n)122Xe and 110Pd(18O,4n)124Xe at a beam energy of 66 MeV were used for this experiment. The lifetimes of the 2+, 4+, 6+, and 8+ states of the ground state band were extracted using the computer code LIFETIME including the corrections due to the side feeding and the nuclear deorientation effects. The lifetime of the 2+ state in 122Xe agrees with the recoil distance method (RDM) measurements but for the 124Xe it does not agree with the RDM measurements but agrees with the Coulomb-excitation experiment. The measured B(E2) values for both the nuclei are compared with the standard algebraic and the multishell models.

Design of nuclear pulse shaped circuit based on proportional counter

International Nuclear Information System (INIS)

Song Qianqian; Cheng Yi; Tuo Xianguo

2011-01-01

Use the self-developed proportional to sample gas tritium in environment and make the measurement. For this detector, a kind of pulse shape circuit based on second order active low pass filtering circuit realized filtering and shaping nuclear pulse by high-speed operational amplifier, with less stages that has been approved for filter Gaussian wave. Use Multisim 10.0 to simulate the different parameters of the filter circuit. The simulation result was consistent with the theoretical results. The experiments proved the feasibility of this circuit, and at the same time provided a convenient and reliable method for analysis and optimization of the nuclear pulse waveform in order for discriminating by MCA. (authors)

The Proportional Counter. Some Aspects of Operation; Le compteur proportionnel. Ses caracteristiques de fonctionnement; Proportsional'nyj schetchik. Nekotorye aspekty raboty; El contador proportional. Sus caracteristicas de funcionamiento

Energy Technology Data Exchange (ETDEWEB)

Curran, S C [Awre, Aldermaston (United Kingdom)

1960-06-15

1. Work on a counter system designed for electron capture studies has shown that the diameter of the anode wire in a high-pressure proportional counter can have an important influence on the energy resolution obtained in measurements of low-energy radiations. In a counter working at a pressure of 12 atmospheres the width of the pulse distribution due to 13.5 keV K-capture radiations could be changed from 65% to 17% by changing the wire diameter from 0.0076 mm to 0.0025 mm. This phenomenon is interpreted as an effect of positive ion space charge in the avalanche. For a given gas gain and primary radiation the density of positive ions in the avalanche increases rapidly with pressure of the filling gas, and when the accompanying electric fields are large enough to affect the last stages of the multiplication process the energy resolution of the counter deteriorates. Decrease in diameter of the anode wire increases the externally applied field in the region where multiplication takes place, thus tending to counteract the effect of space charge. Use of 0.0025 mm anode wires has proved satisfactory in new measurements of L/K capture ratios made with a multiwire counter system working at pressures up to 12 atmospheres. The results obtained for L/K capture ratios of Ge{sup 71} and Kr{sup 79} are 0.115 and 0.112 respectively. The same counting system has also been used in a search for M capture in these two isotopes. The low energy of the M capture radiation, 180 eV in Ge{sup 71} and 260 eV in Kr{sup 79}, and its low intensity relative to that of K capture, makes accurate measurement difficult; but peaks attributable to M capture were observed in pulse spectra of both sources. 2. Low-Background Counting - Recent observations made on a combination of proportional counter and scintillation counters (operating as shields) show that there are some real difficulties in devising a relatively simple system of this kind. The performance is inherently very satisfactory but practical

Water droplet spreading and recoiling upon contact with thick-compact maltodextrin agglomerates.

Science.gov (United States)

Meraz-Torres, Lesvia Sofía; Quintanilla-Carvajal, María Ximena; Téllez-Medina, Darío I; Hernández-Sánchez, Humberto; Alamilla-Beltrán, Liliana; Gutiérrez-López, Gustavo F

2011-11-01

The food and pharmaceutical industries handle a number of compounds in the form of agglomerates which must be put into contact with water for rehydration purposes. In this work, liquid-solid interaction between water and maltodextrin thick-compact agglomerates was studied at different constituent particle sizes for two compression forces (75 and 225 MPa). Rapid droplet spreading was observed which was similar in radius to the expected one for ideal, flat surfaces. Contact angle determinations reported oscillations of this parameter throughout the experiments, being indicative of droplet recoiling on top of the agglomerate. Recoiling was more frequent in samples obtained at 225 MPa for agglomerate formation. Agglomerates obtained at 75 MPa exhibited more penetration of the water. Competition between dissolution of maltodextrin and penetration of the water was, probably, the main mechanism involved in droplet recoiling. Micrographs of the wetting marks were characterized by means of image analysis and the measurements suggested more symmetry of the wetting mark at higher compression force. Differences found in the evaluated parameters for agglomerates were mainly due to compaction force used. No significant effect of particle size in recoiling, penetration of water into the agglomerate, surface texture and symmetry was observed. Copyright © 2011 Society of Chemical Industry.

The Performance of the HRIBF Recoil Mass Spectrometry

International Nuclear Information System (INIS)

Ginter, T.N.

1998-01-01

The Recoil Mass Spectrometer (RMS) is a mass separator located at the Holifield Radioactive Ion Beam Facility (HRIBF) at Oak Ridge National Laboratory. This paper describes the RMS, its performance, its detector systems, and discusses some experiments to illustrate its capabilities

RITA, a promising Monte Carlo code for recoil implantation

International Nuclear Information System (INIS)

Desalvo, A.; Rosa, R.

1982-01-01

A computer code previously set up to simulate ion penetration in amorphous solids has been extended to handle with recoil phenomena. Preliminary results are compared with existing experimental data. (author)

Tritium assay in hydrogen gas by proportional counter with magnetic tape recording

International Nuclear Information System (INIS)

Grabczak, J.

1982-03-01

Analytical procedure is discussed concerning routine tritium activity determination in water samples based on hydrogen production from the water sample and radioactivity measurement by gas proportional counting. The method was found to be fully comparable to the widely adopted technique of liquid scintillation counting with electrolytic enrichment

Numerical modeling of working of a multicellular proportional counter aimed to individual dosimetry of neutrons

International Nuclear Information System (INIS)

Bordy, J.M.; Barthe, J.; Boutruche, B.

1993-01-01

The use of a personal dosimeter imposes severe constraints, particularly for tension of polarization and tolerable dimensions. That why a numerical modeling of this detector working is an appreciable help for conception. It allows to determine quickly the influence of modification of different parameters (nature and pressure of gas, dimension of electrodes, dimension of channels, tension of polarization,...) without having to make new prototypes. The aim of this report is to give some numerical results got with a multicellular counter with a cylindrical geometry. 6 figs

A Study of Nuclear Recoils in Liquid Argon Time Projection Chamber for the Direct Detection of WIMP Dark Matter

Energy Technology Data Exchange (ETDEWEB)

Cao, Huajie [Princeton Univ., NJ (United States)

2014-11-01

Robust results of WIMP direct detection experiments depend on rm understandings of nuclear recoils in the detector media. This thesis documents the most comprehensive study to date on nuclear recoils in liquid argon - a strong candidate for the next generation multi-ton scale WIMP detectors. This study investigates both the energy partition from nuclear recoil energy to secondary modes (scintillation and ionization) and the pulse shape characteristics of scintillation from nuclear recoils.

A study of nuclear recoil backgrounds in dark matter detectors

Science.gov (United States)

Westerdale, Shawn S.

Despite the great success of the Standard Model of particle physics, a preponderance of astrophysical evidence suggests that it cannot explain most of the matter in the universe. This so-called dark matter has eluded direct detection, though many theoretical extensions to the Standard Model predict the existence of particles with a mass on the 1-1000 GeV scale that interact only via the weak nuclear force. Particles in this class are referred to as Weakly Interacting Massive Particles (WIMPs), and their high masses and low scattering cross sections make them viable dark matter candidates. The rarity of WIMP-nucleus interactions makes them challenging to detect: any background can mask the signal they produce. Background rejection is therefore a major problem in dark matter detection. Many experiments greatly reduce their backgrounds by employing techniques to reject electron recoils. However, nuclear recoil backgrounds, which produce signals similar to what we expect from WIMPs, remain problematic. There are two primary sources of such backgrounds: surface backgrounds and neutron recoils. Surface backgrounds result from radioactivity on the inner surfaces of the detector sending recoiling nuclei into the detector. These backgrounds can be removed with fiducial cuts, at some cost to the experiment's exposure. In this dissertation we briefly discuss a novel technique for rejecting these events based on signals they make in the wavelength shifter coating on the inner surfaces of some detectors. Neutron recoils result from neutrons scattering off of nuclei in the detector. These backgrounds may produce a signal identical to what we expect from WIMPs and are extensively discussed here. We additionally present a new tool for calculating (alpha, n) yields in various materials. We introduce the concept of a neutron veto system designed to shield against, measure, and provide an anti-coincidence veto signal for background neutrons. We discuss the research and development

A Study of Nuclear Recoil Backgrounds in Dark Matter Detectors

Energy Technology Data Exchange (ETDEWEB)

Westerdale, Shawn S. [Princeton Univ., NJ (United States)

2016-01-01

Despite the great success of the Standard Model of particle physics, a preponderance of astrophysical evidence suggests that it cannot explain most of the matter in the universe. This so-called dark matter has eluded direct detection, though many theoretical extensions to the Standard Model predict the existence of particles with a mass on the $1-1000$ GeV scale that interact only via the weak nuclear force. Particles in this class are referred to as Weakly Interacting Massive Particles (WIMPs), and their high masses and low scattering cross sections make them viable dark matter candidates. The rarity of WIMP-nucleus interactions makes them challenging to detect: any background can mask the signal they produce. Background rejection is therefore a major problem in dark matter detection. Many experiments greatly reduce their backgrounds by employing techniques to reject electron recoils. However, nuclear recoil backgrounds, which produce signals similar to what we expect from WIMPs, remain problematic. There are two primary sources of such backgrounds: surface backgrounds and neutron recoils. Surface backgrounds result from radioactivity on the inner surfaces of the detector sending recoiling nuclei into the detector. These backgrounds can be removed with fiducial cuts, at some cost to the experiment's exposure. In this dissertation we briefly discuss a novel technique for rejecting these events based on signals they make in the wavelength shifter coating on the inner surfaces of some detectors. Neutron recoils result from neutrons scattering from nuclei in the detector. These backgrounds may produce a signal identical to what we expect from WIMPs and are extensively discussed here. We additionally present a new tool for calculating ($\\alpha$, n)yields in various materials. We introduce the concept of a neutron veto system designed to shield against, measure, and provide an anti-coincidence veto signal for background neutrons. We discuss the research and

Distributed performance counters

Science.gov (United States)

Davis, Kristan D; Evans, Kahn C; Gara, Alan; Satterfield, David L

2013-11-26

A plurality of first performance counter modules is coupled to a plurality of processing cores. The plurality of first performance counter modules is operable to collect performance data associated with the plurality of processing cores respectively. A plurality of second performance counter modules are coupled to a plurality of L2 cache units, and the plurality of second performance counter modules are operable to collect performance data associated with the plurality of L2 cache units respectively. A central performance counter module may be operable to coordinate counter data from the plurality of first performance counter modules and the plurality of second performance modules, the a central performance counter module, the plurality of first performance counter modules, and the plurality of second performance counter modules connected by a daisy chain connection.

Coincidence measurements of slow recoil ions with projectile ions in 42-MeV Arq+-Ar collisions

International Nuclear Information System (INIS)

Tonuma, T.; Kumagai, H.; Matsuo, T.; Tawara, H.

1989-01-01

Slow Ar recoil-ion production cross sections by projectiles of 1.05-MeV/amu Ar q+ (q=4,6,8,10,12,14) were measured using a projectile-ion--recoil-ion coincidence technique. The present results indicate that the average recoil ion charges left-angle i right-angle increase with increasing the incident projectile charge q and the number of the lost and captured electrons from and/or into projectiles, whereas the projectile charge-changing cross sections for loss ionization decrease steeply with increasing q for low-charge-state projectiles, and those for transfer ionization increase rapidly with increasing q for high-charge-state projectiles. For Ar projectiles with q=10, which corresponds to the equilibrium charge state of Ar projectiles at the present collision energy, the average recoil-ion charges are nearly the same in both loss and transfer ionization, and a pure ionization process plays a much more important role in producing highly charged recoil ions, in contrast to projectile electron loss or transfer processes, which play a role in other projectile charge states

Atom location using recoil ion spectroscopy

International Nuclear Information System (INIS)

O'Connor, D.J.

1985-01-01

Low energy ion scattering (LEIS) using inert gas and alkali ions is widely used in studies of the surface atomic layer. The extreme surface sensitivity of this technique ensures that it yields both compositional and structural information on clean and adsorbate covered surfaces. Low Energy Negative recoil Spectroscopy (LENRS) has been applied to a study of oxygen on Ni(110) to gauge the sensitivity to coverage and site location

2π proportional counting chamber for large-area-coated β sources

Indian Academy of Sciences (India)

The system consists of a multiwire-based proportional counter with gas ... volume of the detector to avoid any loss of detection efficiency due to absorption in the entrance ... Figure 1. (a) Energy levels of 90Sr decay scheme and (b) energy distribution of β- ... High voltage is applied to the anode grid and high electric field is.

Recoil effects in multiphoton electron-positron pair creation

International Nuclear Information System (INIS)

Krajewska, K.; Kaminski, J. Z.

2010-01-01

Triply differential probability rates for electron-positron pair creation in laser-nucleus collisions, calculated within the S-matrix approach, are investigated as functions of the nuclear recoil. Pronounced enhancements of differential probability rates of multiphoton pair production are found for a nonzero momentum transfer from the colliding nucleus. The corresponding rates show a very dramatic dependence on the polarization of the laser field impinging on the nucleus; only for a linearly polarized light are the multiphoton rates for electron-positron pair production considerably large. We focus therefore on this case. Our numerical results for different geometries of the reaction particles demonstrate that, for the linearly polarized laser field of an infinite extent (which is a good approximation for femtosecond laser pulses), the pair creation is far more efficient if the nucleus is detected in the direction of the laser-field propagation. The corresponding angular distributions of the created particles show that the high-energy pairs are predominantly produced in the plane spanned by the polarization vector and the laser-field propagation direction, while the low-energy pairs are rather spread around the latter of the two directions. The enhancement of differential probability rates at each energy sector, defined by the four-momentum conservation relation, is observed with varying the energy of the produced particles. The total probability rates of pair production are also evaluated and compared with the corresponding results for the case when one disregards the recoil effect. A tremendous enhancement of the total probability rates of the electron-positron pair creation is observed if one takes into account the nuclear recoil.

Production, transport and charge capture measurements of highly charged recoil ions

International Nuclear Information System (INIS)

Trebus, U.E.

1989-01-01

An experiment is described to study highly charged recoil ions on-line to the heavy accelerator UNILAC at GSI. The highly charged recoil ions are produced by heavy-ion bombardment of a gas target. Subsequently the slow highly charged recoil ions are extracted from the ionization volume, and guided through a beam transport line to a Wien filter for charge state selection and to a collision region to study charge transfer processes. Several experiments were carried out to show the efficient charge state separation. Charge states up to q = 15 were observed. When using a retarding field analyzer cross sections for single electron capture were determined for different charge states of Xe q+ for q = 4 to 11 and He gas. The experiments demonstrated increasing charge transfer cross sections with increasing charge state q and indicated the effect of near resonant charge capture for q = 6. The flexible data acquisition system used, is described and other future experiments, such as for instance in flight ion-trapping are indicated in the appendix

Heavy ion elastic recoil detection analysis of optoelectronic and semiconductor devices

Energy Technology Data Exchange (ETDEWEB)

Dytlewski, N.; Cohen, D.D. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia); Johnston, P.; Walker, S. [Royal Melbourne Inst. of Tech., VIC (Australia); Whitlow, H.; Hult, M. [Lund Univ. (Sweden); Oestling, M.; Zaring, C. [Royal Inst. of Tech., Stockholm (Sweden)

1993-12-31

In recent years, the use of heavy ion time-of-flight elastic recoil spectrometry (HIERDA) has been applied to analyse multi-phase, thin layer devices used in optoelectronics, semiconductors and solar power generation. HIERDA gives simultaneously, mass resolved elemental concentration vs depth profiles of the matrix constituents, and is particularly suited to the determination of light elements in a heavy matrix. The beam/target interaction process is similar to RBS, but has the difference that the recoiling target atoms are detected instead of the scattered projectile. High energy, heavy ions beams bombard the sample, ejecting recoil atoms which are detected at a forward angle of 45 deg. A time-of-flight and total energy detection system enables the ejected particle`s mass to be identified, and allows energy spectra to be obtained and interpreted in an analogous way to RBS, but with the important difference that the elemental spectra are separated, and not superimposed on a background as in RBS. Some of the measurements made with a HIERDA system on the ANTARES Tandem Accelerator at ANSTO are described. 1 refs., 4 figs.

Heavy ion elastic recoil detection analysis of optoelectronic and semiconductor devices

Energy Technology Data Exchange (ETDEWEB)

Dytlewski, N; Cohen, D D [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia); Johnston, P; Walker, S [Royal Melbourne Inst. of Tech., VIC (Australia); Whitlow, H; Hult, M [Lund Univ. (Sweden); Oestling, M; Zaring, C [Royal Inst. of Tech., Stockholm (Sweden)

1994-12-31

In recent years, the use of heavy ion time-of-flight elastic recoil spectrometry (HIERDA) has been applied to analyse multi-phase, thin layer devices used in optoelectronics, semiconductors and solar power generation. HIERDA gives simultaneously, mass resolved elemental concentration vs depth profiles of the matrix constituents, and is particularly suited to the determination of light elements in a heavy matrix. The beam/target interaction process is similar to RBS, but has the difference that the recoiling target atoms are detected instead of the scattered projectile. High energy, heavy ions beams bombard the sample, ejecting recoil atoms which are detected at a forward angle of 45 deg. A time-of-flight and total energy detection system enables the ejected particle`s mass to be identified, and allows energy spectra to be obtained and interpreted in an analogous way to RBS, but with the important difference that the elemental spectra are separated, and not superimposed on a background as in RBS. Some of the measurements made with a HIERDA system on the ANTARES Tandem Accelerator at ANSTO are described. 1 refs., 4 figs.

Production, transport and charge capture measurements of highly charged recoil ions

International Nuclear Information System (INIS)

Trebus, U.E.

1989-05-01

An experiment is described to study highly charged recoil ions on-line to the heavy ion accelerator UNILAC at GSI. The highly charged recoil ions are produced by heavy ion bombardment of a gas target. Subsequently the slow highly charged recoil ions are extracted from the ionization volume, and guided through a beam transport line to a Wien filter for charge state selection and to a collision region to study charge transfer processes. Several experiments were carried out to show the efficient charge state separation. Charge states up to q=15 were observed. When using a retarding field analyzer cross sections for single electron capture were determined for different charge states of Xe q+ for q=4 to 11 and He gas. The experiments demonstrated increasing charge transfer cross sections with increasing charge state q and indicated the effect of near resonant charge capture for q=6. The flexible data acquisition system used, is described and other future experiments, such as for instance in flight ion-trapping are indicated in the appendix. (orig.)

Recoil-proton polarization in πp elastic scattering at 547 and 625 MeV/c

International Nuclear Information System (INIS)

Seftor, C.J.; Adrian, S.D.; Briscoe, W.J.; Mokhtari, A.; Taragin, M.F.; Sadler, M.E.; Barlow, D.B.; Nefkens, B.M.K.; Pillai, C.

1989-01-01

The polarization of the recoil proton in π + p and π - p elastic scattering using a liquid-hydrogen target has been measured for backward angles at 547 and 625 MeV/c. The scattered pion and recoil proton were detected in coincidence using the large-acceptance spectrometer to detect and analyze the momentum of the pions and the JANUS polarimeter to identify and measure the polarization of the protons. Results from this experiment agree with other measurements of the recoil polarization, with analyzing-power data previously taken by this group, and with predictions of partial-wave analyses

Study and full simulation of ten different gases on sealed Multi-Wire Proportional Counter (MWPC) by using Garfield and Maxwell codes

International Nuclear Information System (INIS)

Shohani, M. Ebrahimi; Golgoun, S.M.; Aminipour, M.; Shabani, A.; Mazoochi, A.R.; Akbari, R. Maghsoudi; Mohammadzadeh, M.; Davarpanah, M.R.; Sardari, D.; Sadeghi, M.; Mofrad, F. Babapour; Jafari, A.

2016-01-01

In this research gas sealed Multi-Wire Proportional Counter (MWPC) including blades between anode wires and beta particles of "9"0Sr with 196 keV mean energy were considered. Ten different gases such as Noble gases mixtures with methane and several other pure gases were studied. In this type of detector, by using Garfield and Maxwell codes and for each of the gases, variation of different parameters such as first Townsend, electron attachment coefficients with variable electric field and their effects on pulse height or collected charge and in turn on Signal to Noise Ratio (SNR) were studied. Also the effect of anode voltage and its diameter and the pressure of gas on the pulse height were studied. Results show that Garfield and Maxwell codes can be used to study and improve the design of other gaseous detectors. - Highlights: • Simulation of different gases that is applicable for various gas detectors. • Two simulation codes were used and analyzed their results for beta particle. • Different detector parameters were studied (SNR, first Townsend, electron attachment coefficients, anode voltage and etc.). • The effect of blade in the detector were assessed. • The codes are useful for design and improvement of detector.

Recoil Considerations for Shoulder-Fired Weapons

Science.gov (United States)

2012-05-01

than would be deduced from the force levels defined by the pressure-time curve of the cartridge. Further and just like a large-caliber weapon mounted...force. If each of the force curves over the time interval were integrated, the result should be the same as that derived from a ballistic pendulum...Kathe, E.; Dillon, R. Sonic Rarefaction Wave Low Recoil Gun; Report ARCCB-TR-2001; U.S. Army Armament Research, Development, and Engineering Center

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

Lifetime measurements using the recoil distance method—achievements and perspectives

Science.gov (United States)

Krücken, R.

2001-07-01

The recoil distance method (RDM) for measuring pico-second nuclear level lifetimes and its use in nuclear structure studies is reviewed and perspectives for the future are presented. High precision measurements in the mass-130 region, studies of multi-phonon states in rare earth nuclei, the investigation of shape coexistence and the recently discovered phenomenon of "magnetic rotation" are reviewed. Prospects for lifetime measurements in exotic regions of nuclei such as the measurement of lifetimes in neutron rich nuclei populated via spontaneous and heavy-ion induced fission are discussed. Other prospects include the use of the RDM technique in conjunction with recoil separators. The relevance of these techniques for experiments with radioactive ion beams will be discussed.

Lifetime measurements using the recoil distance method - achievements and perspectives

International Nuclear Information System (INIS)

Kruecken, R.

2001-01-01

The recoil distance method (RDM) for measuring pico-second nuclear level lifetimes and its use in nuclear structure studies is reviewed and perspectives for the future are presented. High precision measurements in the mass-130 region, studies of multi-phonon states in rare earth nuclei, the investigation of shape coexistence and the recently discovered phenomenon of 'magnetic rotation' are reviewed. Prospects for lifetime measurements in exotic regions of nuclei such as the measurement of lifetimes in neutron rich nuclei populated via spontaneous and heavy-ion induced fission are discussed. Other prospects include the use of the RDM technique in conjunction with recoil separators. The relevance of these techniques for experiments with radioactive ion beams will be discussed

Accurate measurements of E2 lifetimes using the coincidence recoil-distance method

International Nuclear Information System (INIS)

Bhalla, R.K.; Poletti, A.R.

1984-01-01

Mean lives of four E2 transitions in the (2s, 1d) shell have been measured using the recoil-distance method (RDM). γ-rays de-exciting the level of interest were detected in coincidence with particles detected in an annular detector at a backward angle thereby reducing the background and producing a beam of recoiling nuclei of well-defined energy and recoil direction. Lifetimes measured were: 22 Ne, 1.275 MeV level (2 + -> 0 + ), 5.16 +- 0.13 ps; 26 Mg, 3.588 MeV level (0 + -> 2 + ), 9.29 +- 0.23 ps; 30 Si, 3.788 MeV level (0 + -> 2 + ), 12.00 +- 0.70 ps; 38 Ar, 3.377 MeV level (0 + -> 2 + ), 34.5 +- 1.5 ps. The present measurements are compared to those of previous investigators. For the 22 Ne level, averaged results from four different measurement techniques are compared and found to be in good agreement. The experimental results are compared to shell-model calculations. (orig.)

Primary processes and ionic reactions in the chemistry of recoiling silicon atoms

International Nuclear Information System (INIS)

Gaspar, P.P.; Garmestani, K.; Boo, B.H.; Stewart, G.W.

1993-01-01

Hot atom chemistry has permitted the elucidation of the chemistry of free atoms, and these include the polyvalent atoms of refractory group 14 elements, that is, carbon, silicon and germanium. Since no more than two bonds are formed normally in a single reactive collision of free atoms, the study on the chemistry of atoms like C, Si and Ge that require the formation of more than two bonds to saturate their chemical valence necessarily involves the study of reactive intermediates. By the studies on the chemistry of recoiling 31 Si atoms, the mechanistic conclusions reached are reported. The most important unanswered questions concerning the reaction of recoiling 31 Si atoms in the systems are shown, and progress has been made toward the answering. By using tetramethyl silane as a trapping agent for silicon ions, it has been established that the reaction of 31 Si ions contributes significantly to the formation of products in recoil systems. The studies by various researchers on this theme are reported. (K.I.)

Test of a superheated superconducting granule detector with nuclear recoil measurements

International Nuclear Information System (INIS)

Berger, C.; Czapek, G.; Diggelmann, U.; Flammer, I.; Frei, D.; Furlan, M.; Gabutti, A.; Janos, S.; Moser, U.; Pretzl, K.; Schmiemann, K.; Perret-Gallix, D.; Konter, J.A.; Mango, S.

1993-01-01

The presented results are part of a Superheated Superconducting Granule (SSG) detector development for neutrinos and dark matter. An aluminum SSG detector was exposed to a 70MeV neutron beam to test the detector sensitivity to nuclear recoils. The neutron scattering angels were determined using a scintillator hodoscope. Coincidences between the SSG and the hodoscope signals have been clearly established. Data were taken at an operating temperature of 120mK for different SSG intrinsic thresholds. The proved sensitivity of the detector to nuclear recoils above 10keV is encouraging for possible applications of SSG as a dark matter detector. (orig.)

Dynamical Formation of Horizons in Recoiling D Branes

CERN Document Server

Ellis, Jonathan Richard; Nanopoulos, Dimitri V; Ellis, John

2000-01-01

A toy calculation of string/D-particle interactions within a world-sheet approach indicates that quantum recoil effects - reflecting the gravitational back-reaction on space-time foam due to the propagation of energetic particles - induces the appearance of a microscopic event horizon, or `bubble', inside which stable matter can exist. The scattering event causes this horizon to expand, but we expect quantum effects to cause it to contract again, in a `bounce' solution. Within such `bubbles', massless matter propagates with an effective velocity that is less than the velocity of light in vacuo, which may lead to observable violations of Lorentz symmetry that may be tested experimentally. The conformal invariance conditions in the interior geometry of the bubbles select preferentially three for the number of the spatial dimensions, corresponding to a consistent formulation of the interaction of D3 branes with recoiling D particles, which are allowed to fluctuate independently only on the D3-brane hypersurface.

The Energy Variation of the Sensitivity of a Polyethylene Moderated BF{sub 3} Proportional Counter

Energy Technology Data Exchange (ETDEWEB)

Fraeki, R; Leimdoerfer, M; Malmskog, S

1962-11-15

The variation with neutron energy of the sensitivity of a polyethylene moderated boron counter has been investigated experimentally at 2.3 MeV, 550 keV, 210 keV, 110 keV, 340 eV and 5 eV, and theoretically by the multigroup diffusion method in the same range. Different moderator thicknesses up to 10 cm were considered Results show good agreement between experimental and theoretical sensitivities for the keV and MeV energies, while a discrepancy of the order of a factor 2 at the most is obtained in the eV region.

Over-the-counter medications containing diphenhydramine and doxylamine used by older adults to improve sleep.

Science.gov (United States)

Abraham, Olufunmilola; Schleiden, Loren; Albert, Steven M

2017-08-01

Background The unintentional misuse of over-the-counter sleep aids among older adults is an important public health problem and a focus of Healthy People 2020. Accordingly, the 2015 Beers Criteria for Potentially Inappropriate Medication Use in Older Adults recommends that individuals 65 years or older avoid use of diphenhydramine and doxylamine; however, many over-the-counter sleep products contain these active ingredients. Objective To identify the proportion of older adults using an over-the-counter medication containing diphenhydramine or doxylamine, and compare their characteristics with older adults using an over-the-counter medication that does not contain these ingredients. Setting Study participants were recruited from the Community Registry of the Pittsburgh Claude D. Pepper Older Americans Independence Center. Method The study sample was taken from a larger survey of 1025 participants on sleep health and over-the-counter sleep medication use conducted from February to April 2015. A subset of 169 participants aged 65 and older reporting taking at least one over-the-counter product to improve sleep within the past 30 days (16.5%) were selected for our analysis on associations between participant characteristics and potentially inappropriate use of over-the-counter sleep medications. Main outcome measure The proportion and characteristics of older adults taking at least one over-the-counter medication containing diphenhydramine or doxylamine. Results Of the 223 over-the-counter sleep medications listed by participants, 115 (52%) contained diphenhydramine or doxylamine. Using the Beers Criteria, we found that more than half of participants (59%) had used a potentially inappropriate over-the-counter medication containing diphenhydramine or doxylamine to improve sleep within the past 30 days. Participants taking at least one diphenhydramine or doxylamine containing medication were less likely to be aware of any safety risks in taking over-the-counter sleep

Superheated superconducting granule detector tested with nuclear recoil measurements

International Nuclear Information System (INIS)

Berger, C.; Czapek, G.; Diggelmann, U.; Flammer, I.; Frei, D.; Furlan, M.; Gabutti, A.; Janos, S.; Moser, U.; Pretzl, K.; Schmiemann, K.; Perret-Gallix, D.; Brandt, B. van den; Konter, J.A.; Mango, S.

1993-01-01

The presented results are part of a superheated superconducting granule (SSG) detector development for neutrino and dark matter. The aim of the experiment was to measure the sensitivity of the detector to nuclear recoil energies when exposed to a 70 MeV neutron beam. The detector consists of a small readout coil (diameter 5 mm, length 10 mm) filled with aluminum granules of average diameter 23 μm embedded in an Al 2 O 3 granulate with a 6% volume filling factor. The neutron scattering angles were determined using a scintillator hodoscope. Coincidences between the SSG and the hodoscope signals have been clearly established. Data were taken at an operating temperature of 120 mK for different SSG intrinsic thresholds. The results prove the sensitivity of the detector to nuclear recoils around 10 keV. (orig.)

Dama annual modulation from electron recoils

OpenAIRE

Foot, R.

2018-01-01

Plasma dark matter, which arises in dissipative dark matter models, can give rise to large annual modulation signals from keV electron recoils. Previous work has argued that the DAMA annual modulation signal might be explained in such a scenario. Detailed predictions are difficult due to the inherent complexities involved in modelling the halo plasma interactions with Earth bound dark matter. Here, we consider a simplified phenomenological model for the dark matter density and temperature nea...

On the limitations introduced by energy spread in elastic recoil detection analysis

International Nuclear Information System (INIS)

Szilagyi, E.

2001-01-01

Improvements in experimental techniques have led to monolayer depth resolution in heavy ion elastic recoil detection analysis (HI-ERDA). Evaluation of the spectra, however, is not trivial. The spectra, using even the best experimental set-up, are subject to finite energy resolution of both extrinsic and intrinsic origin. A proper account for energy spread is necessary to extract the correct depth profile from the measured spectra. With calculation of the correct energy (or depth) resolution of a given method, one can decide in advance whether or not the method will resolve details of interest in the depth profile. To achieve the best depth resolution, it is also possible to find optimum parameters for the experiments. The limitations introduced by the energy spread effects are discussed. An example for simulation is shown for high energy resolution HI-ERDA measurements. Satisfactory agreement between the simulated and the measured HI-ERDA spectra taken by 60 MeV 127 I 23+ ions on highly oriented pyrolythic graphite (HOPG) sample is found, in spite of the non-equilibrium charge state of the recoils and the difference in the stopping powers caused by the given charge state of the incident ion and the recoil, which are not taken into account. To achieve more precise data evaluation these effects should be included in simulation codes, or all the subspectra corresponding to different recoils charge states should be measured and summed

On the limitations introduced by energy spread in elastic recoil detection analysis

Energy Technology Data Exchange (ETDEWEB)

Szilagyi, E. E-mail: szilagyi@rmki.kfki.hu

2001-07-01

Improvements in experimental techniques have led to monolayer depth resolution in heavy ion elastic recoil detection analysis (HI-ERDA). Evaluation of the spectra, however, is not trivial. The spectra, using even the best experimental set-up, are subject to finite energy resolution of both extrinsic and intrinsic origin. A proper account for energy spread is necessary to extract the correct depth profile from the measured spectra. With calculation of the correct energy (or depth) resolution of a given method, one can decide in advance whether or not the method will resolve details of interest in the depth profile. To achieve the best depth resolution, it is also possible to find optimum parameters for the experiments. The limitations introduced by the energy spread effects are discussed. An example for simulation is shown for high energy resolution HI-ERDA measurements. Satisfactory agreement between the simulated and the measured HI-ERDA spectra taken by 60 MeV {sup 127}I{sup 23+} ions on highly oriented pyrolythic graphite (HOPG) sample is found, in spite of the non-equilibrium charge state of the recoils and the difference in the stopping powers caused by the given charge state of the incident ion and the recoil, which are not taken into account. To achieve more precise data evaluation these effects should be included in simulation codes, or all the subspectra corresponding to different recoils charge states should be measured and summed.

Controllability analysis and testing of a novel magnetorheological absorber for field gun recoil mitigation

Science.gov (United States)

Ouyang, Qing; Zheng, Jiajia; Li, Zhaochun; Hu, Ming; Wang, Jiong

2016-11-01

This paper aims to analyze the effects of combined working coils of magnetorheological (MR) absorber on the shock mitigation performance and verify the controllability of MR absorber as applied in the recoil system of a field gun. A physical scale model of the field gun is established and a long-stroke MR recoil absorber with four-stage parallel electromagnetic coils is designed to apply separate current to each stage and generate variable magnetic field distribution in the annular flow channel. Based on dynamic analysis and firing stability conditions of the field gun, ideal recoil force-stroke profiles of MR absorber at different limiting firing angles are obtained. The experimental studies are carried out on an impact test rig under different combinations of current loading: conventional unified control mode, separate control mode and timing control mode. The fullness degree index (FDI) is defined as the quantitative evaluation criterion of the controllability of MR absorber during the whole recoil motion. The results show that the force-stroke profile of the novel MR absorber can approach the ideal curve within 25 degrees of the limiting firing angle through judicious exploitation of the adjustable rheological properties of MR fluid.

Nuclear recoil energy scale in liquid xenon with application to the direct detection of dark matter

International Nuclear Information System (INIS)

Sorensen, Peter; Dahl, Carl Eric

2011-01-01

We show for the first time that the quenching of electronic excitation from nuclear recoils in liquid xenon is well-described by Lindhard theory, if the nuclear recoil energy is reconstructed using the combined (scintillation and ionization) energy scale proposed by Shutt et al. We argue for the adoption of this perspective in favor of the existing preference for reconstructing nuclear recoil energy solely from primary scintillation. We show that signal partitioning into scintillation and ionization is well described by the Thomas-Imel box model. We discuss the implications for liquid xenon detectors aimed at the direct detection of dark matter.

Investigation of complete and incomplete fusion in 20Ne + 51V system using recoil range measurement

Directory of Open Access Journals (Sweden)

Ali Sabir

2015-01-01

Full Text Available Recoil range distributions of evaporation residues, populated in 20Ne + 51V reaction at Elab ≈ 145 MeV, have been studied to determine the degree of momentum transferred through the complete and incomplete fusion reactions. Evaporation residues (ERs populated through the complete and incomplete fusion reactions have been identified on the basis of their recoil range in the Al catcher medium. Measured recoil range of evaporation residues have been compared with the theoretical value calculated using the code SRIM. Range integrated cross section of observed ERs have been compared with the value predicted by statistical model code PACE4.

Accurate measurements of E2 lifetimes using the coincidence recoil-distance method

Science.gov (United States)

Bhalla, R. K.; Poletti, A. R.

1984-05-01

Mean lives of four E2 transitions in the (2s, 1d) shell have been measured using the recoil-distance method (RDM), γ-rays de-exciting the level of interest were detected in coincidence with particles detected in an annular detector at a backward angle thereby reducing the background and producing a beam of recoiling nuclei of well-defined energy and recoil direction. Lifetimes measured were: 22Ne, 1.275 MeV level (2 + → 0 +), 5.16±0.13 ps; 26Mg, 3.588 MeV level (0 + → 2 +), 9.29±0.23 ps; 30Si, 3.788 MeV level (0 +→ 2 +), 12.00±0.70 ps; 38Ar, 3.377 MeV level (0 + → 2 +), 34.5±1.5 ps. The present measurements are compared to those of previous investigators. For the 22Ne level, averaged results from four different measurement techniques are compared and found to be in good agreement. The experimental results are compared to shell-model calculations.

Role of the recoil effect in two-center interference in X-ray photoionization

International Nuclear Information System (INIS)

Ueda, K.; Liu, X.-J.; Pruemper, G.; Lischke, T.; Tanaka, T.; Hoshino, M.; Tanaka, H.; Minkov, I.; Kimberg, V.; Gel'mukhanov, F.

2006-01-01

X-ray photoelectron spectra of the N 2 molecule are studied both experimentally and theoretically in the extended energy region up to 1 keV. The ratio of the photoionization cross sections for the gerade and ungerade core levels displays a modulation in the high energy region caused by the two-center interference, as predicted by Cohen and Fano (CF) in 1966. The physical background of this CF effect is the same as in Young's double-slit experiment. We have found that the interference pattern deviates significantly from the CF prediction. The origin of such a breakdown of the CF formula is the scattering of the photoelectron inside the molecule and the momentum transfer from the emitted fast photoelectron to the nuclei. Usually the recoil effect is small. We show that the electron recoil strongly affects the two-center interference pattern. Both stationary and dynamical aspects of the recoil effect shed light on the role of the momentum exchange in the two-center interference

SIMULATIONS OF RECOILING MASSIVE BLACK HOLES IN THE VIA LACTEA HALO

International Nuclear Information System (INIS)

Guedes, J.; Madau, P.; Diemand, J.; Kuhlen, M.; Zemp, M.

2009-01-01

The coalescence of a massive black hole (MBH) binary leads to the gravitational-wave recoil of the system and its ejection from the galaxy core. We have carried out N-body simulations of the motion of a M BH = 3.7 x 10 6 M sun MBH remnant in the 'Via Lactea I' simulation, a Milky Way-sized dark matter halo. The black hole receives a recoil velocity of V kick = 80, 120, 200, 300, and 400 km s -1 at redshift 1.5, and its orbit is followed for over 1 Gyr within a 'live' host halo, subject only to gravity and dynamical friction against the dark matter background. We show that, owing to asphericities in the dark matter potential, the orbit of the MBH is highly nonradial, resulting in a significantly increased decay timescale compared to a spherical halo. The simulations are used to construct a semi-analytic model of the motion of the MBH in a time-varying triaxial Navarro-Frenk-White dark matter halo plus a spherical stellar bulge, where the dynamical friction force is calculated directly from the velocity dispersion tensor. Such a model should offer a realistic picture of the dynamics of kicked MBHs in situations where gas drag, friction by disk stars, and the flattening of the central cusp by the returning black hole are all negligible effects. We find that MBHs ejected with initial recoil velocities V kick ∼> 500 km s -1 do not return to the host center within a Hubble time. In a Milky Way-sized galaxy, a recoiling hole carrying a gaseous disk of initial mass ∼M BH may shine as a quasar for a substantial fraction of its 'wandering' phase. The long decay timescales of kicked MBHs predicted by this study may thus be favorable to the detection of off-nuclear quasar activity.

Experiments with recoil ions and other considerations

Energy Technology Data Exchange (ETDEWEB)

Cocke, C.L.

1987-01-01

Some opportunities in collisions physics with slow, multiply charged ions are addressed. A distinction between inner and outer shell collisions is drawn. The applicability of recoil ion sources to outer shell collision systems is discussed, with emphasis on the quality of the beam desired. An example of an inner shell collision is discussed, and the usefulness of not pushing the collision energy too low is pointed out. 13 refs., 14 figs.

Heavy ion recoil spectrometry of Si{sub x}Ge{sub 1-x} thin films

Energy Technology Data Exchange (ETDEWEB)

Walker, S.R.; Johnston, P.N.; Bubb, I.F. [Royal Melbourne Inst. of Tech., VIC (Australia); Cohen, D.D.; Dytlewski, N. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia); Hult, M.; Whitlow, H.J. [Lund Institute of Technology, Solvegatan (Sweden). Department of Nuclear Physics; Zaring, C.; Oestling, M. [Royal Inst. of Tech., Stockholm (Sweden). Dept. of Solid State Electronics

1993-12-31

Mass and energy dispersive recoil spectrometry employing 77 MeV {sup 127}I ions from ANTARES (FN Tandem) facility at Lucas Heights has been used to examine the isotopic composition of samples of Si{sub x}Ge{sub 1-x} grown at the Australian National University by Electron Beam Evaporation (EBE). The recoiling target nuclei were analysed by a Time Of Flight and Energy (TOF-E) detector telescope composed of two timing pickoff detectors and a surface barrier (energy) detector. From the time of flight and energy, the ion mass can be determined and individual depth distributions for each element can be obtained. Recoil spectrometry has shown the presence of oxygen in the Si{sub x}Ge{sub 1-x} layer and has enabled the separate determination of energy spectra for individual elements. 9 refs., 3 figs.

Heavy ion recoil spectrometry of Si{sub x}Ge{sub 1-x} thin films

Energy Technology Data Exchange (ETDEWEB)

Walker, S R; Johnston, P N; Bubb, I F [Royal Melbourne Inst. of Tech., VIC (Australia); Cohen, D D; Dytlewski, N [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia); Hult, M; Whitlow, H J [Lund Institute of Technology, Solvegatan (Sweden). Department of Nuclear Physics; Zaring, C; Oestling, M [Royal Inst. of Tech., Stockholm (Sweden). Dept. of Solid State Electronics

1994-12-31

Mass and energy dispersive recoil spectrometry employing 77 MeV {sup 127}I ions from ANTARES (FN Tandem) facility at Lucas Heights has been used to examine the isotopic composition of samples of Si{sub x}Ge{sub 1-x} grown at the Australian National University by Electron Beam Evaporation (EBE). The recoiling target nuclei were analysed by a Time Of Flight and Energy (TOF-E) detector telescope composed of two timing pickoff detectors and a surface barrier (energy) detector. From the time of flight and energy, the ion mass can be determined and individual depth distributions for each element can be obtained. Recoil spectrometry has shown the presence of oxygen in the Si{sub x}Ge{sub 1-x} layer and has enabled the separate determination of energy spectra for individual elements. 9 refs., 3 figs.

Recoil ion spectroscopy with heavy ions

International Nuclear Information System (INIS)

Beyer, H.F.; Mann, R.

1984-01-01

This chapter examines the production of very high charge state ions in single ion-atom collisions. Topics considered include some aspects of highly ionized atoms, experimental approaches, the production of highly charged target ions (monoatomic targets, recoil energy distribution, molecular fragmentation, outer-shell rearrangement, lifetime measurements, a comparison of projectile-, target-, and plasma-ion stripping), and secondary collision experiments (selective electron capture, potential applications). The heavy-ion beams for the described experiments were provided by accelerators such as tandem Van de Graaff facility and the UNILAC

Gaseous Multiplication factor measurements on low pressure ethylene

International Nuclear Information System (INIS)

Hevia Vives, Alberto

2008-01-01

The present investigation consists of a study of a Proportional Counter considered as a fundamental part of an Absolute Neutron Dosimeter developed for the Chilean Nuclear Energy Commission. The proportional counter consists of a Polyethylene Cathode of approximately 5 cm in diameter and an Anode consisting of a central wire of 5 μm in diameter. The proportional counter is biased at 650 V. The gas pressure ranges from 12 to 36 Torr of pure Ethylene. The work comes up as a need to obtain gas gain curves (Gas Multiplication Factors) for the proportional counter operated in the conditions as mentioned. This is a consequence of the scarcity of the existing information referred to Ethylene for the range of bias and gas pressure required in this case. Likewise, the research involved in this study contributed with useful information for the institution involved in the design and construction of the neutron dosimeter, as well as for the scientific community through the publication of this work. The results were obtained by using the above-mentioned Neutron Dosimeter but instead of using recoil protons by fast neutrons, the measurements were completed by directly using a 241 Am alpha particle source installed inside the dosimeter. The analysis of results as well as a detailed study of the pulse shapes provided by the proportional counter was performed by using the well-known MathCAD software. This software contains a text interface that includes symbolic and numeric calculations. Results of the research show that for the high Reduced Electric Fields ( Sa > 1500 Volts/cmTorr) used throughout the present work, Townsend law is still valid. This law states that the Multiplication Factors may be considered as dependent on the Reduced Electric Field instead of depending on the bias and gas pressure separately

Elastic recoil detection (ERD) with extremely heavy ions

International Nuclear Information System (INIS)

Forster, J.S.; Davies, J.A.; Siegele, R.; Wallace, S.G.; Zelenitsky, D.

1996-01-01

Extremely heavy-ion beams such as 209 Bi in elastic recoil detection (ERD) make ERD a uniquely valuable technique for thin-film analysis of elements with mass ≤100. We report ERD measurements of compositional analysis of dinosaur eggshells and bones. We also show the capability of the ERD technique on studies of thin-film, high-temperature superconductors. (orig.)

Absolute measurements with a 4 {pi}-counter

Energy Technology Data Exchange (ETDEWEB)

Martinsson, Kerstin

1959-06-15

Measurements on standardized p-emitters have been made in a 4 it proportional flow-counter. The counter efficiency is found to be near 100 %. Absorption curves have been determined with plastic foils and aluminium. A comparison is made between the self-absorption arising in different methods of source preparation which include precipitates and the use of wetting agents The most reliable results have been obtained with sources on aluminium foils, where the foil absorption is calculated from the absorption curves and the self-absorption is supposed to be negligible for isotopes with end point energy above 0.5 MeV. The {beta}-emitters studied have energies ranging from 1.71 MeV ({sup 32}P) to 0.167 MeV ({sup 35}S). Most of them have been obtained from National Physical Laboratory and Atomic Energy Research Establishment, Harwell, England. The agreement between their calibration and our measurements is very good except in the case of Co 60.

Absolute measurements with a 4 π-counter

International Nuclear Information System (INIS)

Martinsson, Kerstin

1959-06-01

Measurements on standardized p-emitters have been made in a 4 it proportional flow-counter. The counter efficiency is found to be near 100 %. Absorption curves have been determined with plastic foils and aluminium. A comparison is made between the self-absorption arising in different methods of source preparation which include precipitates and the use of wetting agents The most reliable results have been obtained with sources on aluminium foils, where the foil absorption is calculated from the absorption curves and the self-absorption is supposed to be negligible for isotopes with end point energy above 0.5 MeV. The β-emitters studied have energies ranging from 1.71 MeV ( 32 P) to 0.167 MeV ( 35 S). Most of them have been obtained from National Physical Laboratory and Atomic Energy Research Establishment, Harwell, England. The agreement between their calibration and our measurements is very good except in the case of Co 60

Characterization of TiAlN thin film annealed under O2 by in situ time of flight direct recoil spectroscopy/mass spectroscopy of recoiled ions and ex situ x-ray photoelectron spectroscopy

International Nuclear Information System (INIS)

Tempez, A.; Bensaoula, A.; Schultz, A.

2002-01-01

The oxidation of an amorphous TiAlN coating has been studied by in situ direct recoil spectroscopy (DRS) and mass spectroscopy of recoiled ions (MSRI) and ex situ x-ray photoelectron spectroscopy (XPS). DRS and MSRI monitored the changes in surface composition as the sample was heated to 460 deg. C under an 18 O 2 pressure of 10 -6 Torr. Angular resolved XPS data were acquired for thickness-dependence information. The initial surface was partially oxidized from air exposure. Both DRS and XPS showed the Al-rich near surface and the presence of N in the subsurface. As shown by DRS and MSRI, oxidation at elevated temperatures yielded surface nitrogen loss and Ti enrichment. XPS confirmed the preferential formation of TiO 2 on the surface. This study also provides a comparison between the direct recoil (neutrals and ions) and the ionic recoil signals. In our conditions, the negative ionic fraction of all elements except H tracks their true surface content variations given by DRS. The results were compared with early work performed on identical samples. In this case the TiAlN film was oxidized with an O 2 pressure in the mTorr range and the surface changes are followed in situ by positive MSRI and XPS. This experiment also indicates that Al and N are buried under TiO 2 but from 600 deg. C

Elastic recoil atomic spectroscopy of light elements with sub-nanometer depth resolution

International Nuclear Information System (INIS)

Kosmata, Marcel

2011-01-01

In this thesis the QQDS magnetic spectrometer that is used for high resolution ion beam analysis (IBA) of light elements at the Helmholtz-Zentrum Dresden-Rossendorf is presented for the first time. In addition all parameters are investigated that influence the analysis. Methods and models are presented with which the effects can be minimised or calculated. There are five focal points of this thesis. The first point is the construction and commissioning of the QQDS magnetic spectrometer, the corresponding scattering chamber with all the peripherals and the detector, which is specially developed for high resolution elastic recoil detection. Both the reconstructed spectrometer and the detector were adapted to the specific experimental conditions needed for high-resolution Ion beam analysis of light elements and tested for routine practice. The detector consists of two components. At the back end of the detector a Bragg ionization chamber is mounted, which is used for the particle identification. At the front end, directly behind the entrance window a proportional counter is mounted. This proportional counter includes a highresistance anode. Thus, the position of the particles is determined in the detector. The following two points concern fundamental studies of ion-solid interaction. By using a magnetic spectrometer the charge state distribution of the particles scattered from the sample after a binary collision is both possible and necessary for the analysis. For this reason the charge states are measured and compared with existing models. In addition, a model is developed that takes into account the charge state dependent energy loss. It is shown that without the application of this model the depth profiles do not correspond with the quantitative measurements by conventional IBA methods and with the thickness obtained by transmission electron microscopy. The second fundamental ion-solid interaction is the damage and the modification of the sample that occurs during

Photoproduction of pions on nuclear in chiral bag model with account of motion effects of recoil nucleon

International Nuclear Information System (INIS)

Dorokhov, A.E.; Kanokov, Z.; Musakhanov, M.M.; Rakhimov, A.M.

1989-01-01

Pion production on a nucleon is studied in the chiral bag model (CBM). A CBM version is investigated in which the pions get into the bag and interact with quarks in a pseudovector way in the entire volume. Charged pion photoproduction amplitudes are found taking into account the recoil nucleon motion effects. Angular and energy distributions of charged pions, polarization of the recoil nucleon, multipoles are calculated. The recoil effects are shon to give an additional contribution to the static approximation of order of 10-20%. At bag radius value R=1 in the calculations are consistent with the experimental data

Hydrogen depth profiling using elastic recoil detection

International Nuclear Information System (INIS)

Doyle, B.L.; Peercy, P.S.

1979-01-01

The elastic recoil detection (ERD) analysis technique for H profiling in the near surface regions of solids is described. ERD is shown to have the capability of detecting H and its isotopes down to concentrations of approx. 0.01 at. % with a depth resolution of a few hundred angstroms. Is is demonstrated that 2.4-MeV He ions can be used successfully to profile 1 H and 2 D using this technique. 12 figures

Measurement of the proton form factors ratio G_E/G_M to Q² = 5.6 GeV² by recoil polarimetry

Energy Technology Data Exchange (ETDEWEB)

Gayou, Olivier [College of William and Mary, Williamsburg, VA (United States)

2002-01-01

In this thesis, we present the results of the experiment E99-007, which measured the ratio of the electric to magnetic form factors of the proton to the four momentum transfer square Q² = 5.6 GeV², by recoil polarimetry. Data were taken in 2000 at the Thomas Jefferson National Accelerator Facility in Virginia, USA. A 4.6 GeV polarized electron beam was scattered off a cryogenic hydrogen target. The polarization of the recoil proton was measured in the Focal Plane Polarimeter, located after one of the two High Resolution Spectrometers in the hall. The ratio of the transverse to longitudinal components of the recoil proton polarization is proportional to the ratio of the form factors. Elastic events were selected by detecting the scattered electron in a large acceptance lead-glass calorimeter. The main result of this experiment is the linear decrease of the form factor ratio with increasing Q², corresponding to different spatial distributions of the electric charge and the magnetization. Numerous theoretical calculations show that relativistic effects, such as mixing of spin states due to Lorentz boosts, are important to account for the observed data in this critical intermediate kinematic region.

Deuterium electrodisintegration at high recoil momentum

International Nuclear Information System (INIS)

Steenholen, G.

1996-01-01

The availability of continuous electron beams made it possible to carry out various deuterium electro-disintegration experiments in kinematical domains corresponding to a high recoil momentum. Three such experiments are discussed: 1) the left-right asymmetry with respect to the direction of the momentum transfer has been measured with good precision; 2) cross sections have been obtained in a kinematical region well above the quasi-elastic peak; 3) data have been taken in quasi-elastic kinematics that can be used to study high-momentum components in the deuterium wave function [ru

Magneto optical trap recoil ion momentum spectroscopy: application to ion-atom collisions

International Nuclear Information System (INIS)

Blieck, J.

2008-10-01

87 Rb atoms have been cooled, trapped and prepared as targets for collision studies with 2 and 5 keV Na + projectiles. The physics studied deals with charge exchange processes. The active electron, which is generally the most peripheral electron of the atomic target, is transferred from the target onto the ionic projectile. The ionized target is called recoil ion. The technique used to study this physics is the MOTRIMS (Magneto Optical Trap Recoil Ion Momentum Spectroscopy) technique, which combines a magneto optical trap and a recoil ion momentum spectrometer. The spectrometer is used for the measurement of the recoil ions momentum, which gives access to all the information of the collision: the Q-value (which is the potential energy difference of the active electron on each particle) and the scattering angle of the projectile. The trap provides extremely cold targets to optimize the measurement of the momentum, and to release the latter from thermal motion. Through cinematically complete experiments, the MOTRIMS technique gives access to better resolutions on momentum measurements. Measurements of differential cross sections in initial and final capture states and in scattering angle have been done. Results obtained for differential cross sections in initial and final states show globally a good agreement with theory and an other experiment. Nevertheless, discrepancies with theory and this other experiment are shown for the measurements of doubly differential cross sections. These discrepancies are not understood yet. The particularity of the experimental setup designed and tested in this work, namely a low background noise, allows a great sensitivity to weak capture channels, and brings a technical and scientific gain compared with previous works. (author)

Fractional momentum transfer in incomplete fusion reaction: measurement of recoil range distributions in 20Ne + 159Tb system

International Nuclear Information System (INIS)

Ali, R.; Singh, D.; Pachouri, Dipti; Afzal Ansari, M.; Rashid, M.H.

2007-01-01

The recoil range distribution (RRD) of several residues have been measured for the system 20 Ne + 159 Tb at 165 MeV beam energy by collecting the recoiling residues in the Al-catcher foils of varying thickness

Cerenkov counters at ISABELLE

International Nuclear Information System (INIS)

Etkin, A.; Kostoulas, I.; Leith, D.W.G.S.; Thun, R.

1977-01-01

The Cherenkov counter described for use at Isabelle is a threshold counter in which light is focussed on phototubes. The counter is applicable in large-angle, small-aperture magnetic spectrometers for measurement of particle yields at large p/sub T/. Three of these counters will provide complete π-K-p separation in the range of 7-20 GeV/c. Other Cherenkov counters are discussed and a bibliography of relevant literature on the counters utilizing photoionization is included

Constraints on the Nature of CID-42: Recoil Kick or Supermassive Black Hole Pair?

Science.gov (United States)

Blecha, Laura; Civano, Francesca; Elvis, Martin; Loeb, Abraham

2012-01-01

The galaxy CXOC J100043.1+020637, also known as CID-42, is a highly unusual object. An apparent galaxy merger remnant, it displays signatures of both an inspiraling, kiloparsecscale active galactic nucleus (AGN) pair and of a recoiling AGN with a kick velocity approximately greater than 1300 km s(exp -1). Among recoiling AGN candidates, CID-42 alone has both spatial offsets (in optical and X-ray bands) and spectroscopic offsets. In order to constrain the relative likelihood of both scenarios, we develop models using hydrodynamic galaxy merger simulations coupled with radiative transfer calculations. Our gas-rich, major merger models are generally well matched to the galactic morphology and to the inferred stellar mass and star formation rate. We show that a recoiling supermassive black hole (SMBH) in CID-42 should be observable as an AGN at the time of observation. However, in order for the recoiling AGN to produce narrow-line emission, it must be observed shortly after the kick while it still inhabits a dense gaseous region, implying a large total kick velocity (vk approximately greater than 2000 km s(exp -1)). For the dual AGN scenario, an unusually large broad-line offset is required, and the best match to the observed morphology requires a galaxy that is less luminous than CID-42. Further, the lack of X-ray emission from one of the two optical nuclei is not easily attributed to an intrinsically quiescent SMBH or to a Compton-thick galactic environment. While the current data do not allow either the recoiling or the dual AGN scenario for CID-42 to be excluded, our models highlight the most relevant parameters for distinguishing these possibilities with future observations. In particular, high-quality, spatially-resolved spectra that can pinpoint the origin of the broad and narrow line features will be critical for determining the nature of this unique source.

Optimizing recoil-isomer tagging with the Argonne fragment mass analyzer

International Nuclear Information System (INIS)

Garnsworthy, A.B.; Lister, C.J.; Regan, P.H.; Blank, B.B.; Cullen, I.J.; Gros, S.; Henderson, D.J.; Jones, G.A.; Liu, Z.; Seweryniak, D.; Shumard, B.R.; Thompson, N.J.; Williams, S.J.; Zhu, S.

2008-01-01

A new focal plane detector arrangement for the Fragment Mass Analyzer (FMA) has been built and tested at Argonne National Laboratory. This set-up is particularly sensitive for performing Recoil-Isomer Tagging on nuclei with isomeric states with lifetimes in the microsecond range. Recoiling nuclei from fusion-evaporation reactions at the target position are dispersed by their ratio of mass to charge (A/q) by the FMA and stopped in low pressure gas (air) at the focal plane. Subsequent gamma decays from isomeric states in the reaction products are observed using Ge detectors. A constant gas flow through the focal plane chamber efficiently removes longer-lived beta-decaying species from sight of the detectors. This set-up has been commissioned successfully with the microsecond isomer in 80 Rb, populated via the 52 Cr( 32 S, 3pn) reaction at 135 MeV

Neutron spectrometry for reactor applications: status, limitations, and future directions

International Nuclear Information System (INIS)

Gold, R.

1975-08-01

The ability of ''state-of-the-art'' reactor neutron spectrometry to provide definitive environmental results required for high fluence radiation damage experiments is reviewed. A formal definition of the neutron component is presented as well as general considerations which accrue from both this definition and the existence of the mixed radiation field generally encountered in reactors. A description of four selected methods of reactor neutron spectrometry is included, namely Proton Recoil (PR) methods, Time-Of-Flight (TOF) methods, the 6 Li(n,α) 3 H coincidence method, and Multiple Foil Activation (MFA) methods. These selected methods are compared. Future requirements and directions for reactor neutron spectrometry are discussed. In particular, the needs of future CTR research are stressed and the He 4 - recoil proportional counter spectroscopy method is advanced as a means of meeting these future requirements. 50 references. (auth)

Detection of nuclear recoils in prototype dark matter detectors, made from Al, Sn and Zn superheated superconducting granules

International Nuclear Information System (INIS)

Abplanalp, M.; Van den Brandt, B.; Konter, J.A.; Mango, S.

1995-01-01

This work is part of an ongoing project to develop a superheated superconducting granule (SSG) detector for cold dark matter and neutrinos. The response of SSG devices to nuclear recoils has been explored irradiating SSG detectors with a 70 MeV neutron beam. The aim of the experiment was to test the sensitivity of Sn, Al and Zn SSG detectors to nuclear recoil energies down to a few keV. The detector consisted of a hollow teflon cylinder (0.1 cm 3 inner volume) filled with tiny superconducting metastable granules embedded in a dielectric medium. The nuclear recoil energies deposited in the SSG were determined measuring the neutron scattering angles with a neutron hodoscope. Coincidences in time between the SSG and the hodoscope signals have been clearly established. In this paper the results of the neutron irradiation experiments at different SSG intrinsic thresholds are discussed and compared to Monte Carlo simulations. The results show that SSG are sensitive to recoil energies down to similar 1 keV. The limited angular resolution of the neutron hodoscope prevented us from measuring the SSG sensitivity to even lower recoil energies. (orig.)

Recoil range distribution measurement in 20Ne + 181Ta reaction

International Nuclear Information System (INIS)

Tripathi, R.; Sudarshan, K.; Goswami, A.; Guin, R.; Reddy, A.V.R.

2005-01-01

In order to investigate linear momentum transfer in various transfer channels in 20 Ne + 181 Ta, recoil range distribution measurements have been carried out at E lab = 180 MeV, populating significant number of l-waves above l crit

Implantation of 111In in NTDSi by heavy ion recoil technique

International Nuclear Information System (INIS)

Thakare, S.V.; Tomar, B.S.

1998-01-01

Heavy ion recoil implantation technique has been used to implant 111 In in n-type silicon using medium energy heavy ion accelerator Pelletron, at TIFR, Colaba, Mumbai. The nuclear reaction used for this purpose was 109 Ag( 7 Li,p4n) 111 In. The beam energy was optimised to be 50 MeV for maximum concentration of the implanted probe atoms. The gamma-ray spectrum of the implanted sample after 24 hours was found to contain only 171 and 245 keV gamma rays of 111 In. The penetration depth of ion is increased to 1.6 μm by heavy ion recoil implantation technique as compared to 0.16 μm with the conventional ion implantation technique. (author)

Binary black holes: Spin dynamics and gravitational recoil

International Nuclear Information System (INIS)

Herrmann, Frank; Hinder, Ian; Shoemaker, Deirdre M.; Laguna, Pablo; Matzner, Richard A.

2007-01-01

We present a study of spinning black hole binaries focusing on the spin dynamics of the individual black holes as well as on the gravitational recoil acquired by the black hole produced by the merger. We consider two series of initial spin orientations away from the binary orbital plane. In one of the series, the spins are antialigned; for the second series, one of the spins points away from the binary along the line separating the black holes. We find a remarkable agreement between the spin dynamics predicted at 2nd post-Newtonian order and those from numerical relativity. For each configuration, we compute the kick of the final black hole. We use the kick estimates from the series with antialigned spins to fit the parameters in the Kidder kick formula, and verify that the recoil in the direction of the orbital angular momentum is ∝sinθ and on the orbital plane ∝cosθ, with θ the angle between the spin directions and the orbital angular momentum. We also find that the black hole spins can be well estimated by evaluating the isolated horizon spin on spheres of constant coordinate radius

The acetone bandpass detector for inverse photoemission: operation in proportional and Geiger–Müller modes

Science.gov (United States)

Thiede, Christian; Niehues, Iris; Schmidt, Anke B.; Donath, Markus

2018-06-01

Inverse photoemission is the most versatile experimental tool to study the unoccupied electronic structure at surfaces of solids. Typically, the experiments are performed in the isochromat mode with bandpass photon detectors. For gas-filled counters, the bandpass behavior is realized by the combination of the photoionization threshold of the counting gas as the high-pass filter and the ultraviolet transmission cutoff of an alkaline earth fluoride entrance window as the low-pass filter. The transmission characteristics of the entrance window determine the optical bandpass. The performance of the counter depends on the composition of the detection gas and the fill-gas pressure, the readout electronics and the counter geometry. For the well-known combination of acetone and CaF2, the detector can be operated in proportional and Geiger–Müller modes. In this work, we review aspects concerning the working principles, the counter construction and the read-out electronics. We identify optimum working parameters and provide a step-by-step recipe how to build, install and operate the device.

DVCS at HERMES. The recoil detector and transverse target spin asymmetries

Energy Technology Data Exchange (ETDEWEB)

Murray, M.J.

2008-02-15

The HERMES experiment is a large forward angle spectrometer located at the HERA accelerator ring at DESY, Hamburg. One of the most exciting topics studied at HERMES is Deeply Virtual Compton Scattering (DVCS) which is the simplest interaction that provides a gateway for access to Generalised Parton Distributions (GPDs). GPDs are a theoretical framework which can be used to calculate the total angular momentum of the quarks in the nucleon. As such, they provide one piece of the puzzle of nucleonic spin structure. In 2005, HERMES was upgraded in the target region with a Recoil Detector that allows it to make truly exclusive measurements of the DVCS interaction for the first time. The design and construction of the Recoil Detector is discussed herein, in addition to a complete analysis of the Transverse Target Spin Asymmetry (TTSA) in DVCS. Experimental facilities that enable measurement of this asymmetry are rare. The importance of the information on the TTSA from HERMES is made yet greater as the transversely polarised target that allows the asymmetry to be measured has been replaced by an unpolarised target. This was to allow the Recoil Detector to be installed. The final stage of this thesis shows a model-dependent method for constraining the angular momentum of the quarks in the nucleon and speculates as to the other pieces of the spin puzzle. (orig.)

DVCS at HERMES. The recoil detector and transverse target spin asymmetries

International Nuclear Information System (INIS)

Murray, M.J.

2008-02-01

The HERMES experiment is a large forward angle spectrometer located at the HERA accelerator ring at DESY, Hamburg. One of the most exciting topics studied at HERMES is Deeply Virtual Compton Scattering (DVCS) which is the simplest interaction that provides a gateway for access to Generalised Parton Distributions (GPDs). GPDs are a theoretical framework which can be used to calculate the total angular momentum of the quarks in the nucleon. As such, they provide one piece of the puzzle of nucleonic spin structure. In 2005, HERMES was upgraded in the target region with a Recoil Detector that allows it to make truly exclusive measurements of the DVCS interaction for the first time. The design and construction of the Recoil Detector is discussed herein, in addition to a complete analysis of the Transverse Target Spin Asymmetry (TTSA) in DVCS. Experimental facilities that enable measurement of this asymmetry are rare. The importance of the information on the TTSA from HERMES is made yet greater as the transversely polarised target that allows the asymmetry to be measured has been replaced by an unpolarised target. This was to allow the Recoil Detector to be installed. The final stage of this thesis shows a model-dependent method for constraining the angular momentum of the quarks in the nucleon and speculates as to the other pieces of the spin puzzle. (orig.)

Implantation, recoil implantation, and sputtering

International Nuclear Information System (INIS)

Kelly, R.

1984-01-01

Underlying ion-beam modification of surfaces is the more basic subject of particle-surface interaction. The ideas can be grouped into forward and backward features, i.e. those affecting the interior of the target and those leading to particle expulsion. Forward effects include the stopping of the incident particles and the deposition of energy, both governed by integral equations which are easily set up but difficult to solve. Closely related is recoil implantation where emphasis is placed not on the stopping of the incident particles but on their interaction with target atoms with resulting implantation of these atoms. Backward effects, all of which are denoted as sputtering, are in general either of collisional, thermal, electronic, or exfoliational origin. (Auth.)

Use of nuclear recoil for separating 228Ra, 224Ra, and 233Pa from colloidal thorium

International Nuclear Information System (INIS)

Beydon, J.; Gratot, I.

1968-01-01

By using α-recoil it is possible to separate by dialysis the α disintegration products (224 Ra; 228 Ra) of thorium from colloidal thorium hydroxide.The use of n, γ recoil allows the separation of 233 Pa produced by the neutron irradiation of thorium, on condition that the colloidal thorium hydroxide is irradiated in the presence of a dispersing. (author) [fr

Electrochemical etching amplification of low-let recoil particle tracks in polymers for fast neutron dosimetry

International Nuclear Information System (INIS)

Sohrabi, M.; Morgan, K.Z.

1975-11-01

An electrochemical etching method for the amplification of fast-neutron-induced recoil particle tracks in polymers was investigated. The technique gave superior results over those obtained by conventional etching methods especially when polycarbonate foils were used for recoil particle track amplification. Electrochemical etching systems capable of multi-foil processing were designed and constructed to demonstrate the feasibility of the techniques for large-scale neutron dosimetry. Electrochemical etching parameters were studied including the nature or type of the polymer foil used, foil thickness and its effect on etching time, the applied voltage and its frequency, the chemical composition, concentration, and temperature of the etchant, distance and angle between the electrodes, and the type of particles such as recoil particles including protons. Recoil particle track density, mean track diameter, and optical density as functions of the mentioned parameters were determined. Each parameter was found to have a distinct effect on the etching results in terms of the measured responses. Several new characteristics of this fast neutron dosimetry method were studied especially for personnel dosimetry using various radiation sources such as nuclear reactors, medical cyclotrons, and isotopic neutron sources. The dose range, neutron energy dependence, directional response, fading characteristics, neutron threshold energy, etc. were investigated

Quality factor calculations for neutron spectra below 4 MeV

International Nuclear Information System (INIS)

Borak, T.B.; Stinchcomb, T.G.

1979-01-01

A method is described for computing the distribution of absorbed dose, D(L), as a function of linear energy transfer, L, for any neutron spectrum with energies below 4 MeV. The results are used to determine the average quality factor for two distinctly different neutron spectra using the ICRP recommended values of the quality factor, Q(L). A comparison is made between the calculations and measurements of D(L) using a spherical tissue equivalent proportional counter. Heavy ion recoil contributions to the average quality factor are examined in detail. (author)

Multimode pulse counter

International Nuclear Information System (INIS)

Natanzon, D.D.

1982-01-01

A pulse counter with code conversion is described. The counter is based on the integrated circuits of direct-counting devices of medium integration. The counter ensures various modes of pulse counting depending on the logical control signals: reversible, two-channel summing, one-channel summing binary, summing with ''storage'' signal code fixation without interrupting pulse counting. Arrangement of the suggested structure as a microcircuit of medium integration might contribute to reduction in the counter type nomenclature in digital families of widely used integrated circuits

Recoil velocity at second post-Newtonian order for spinning black hole binaries

International Nuclear Information System (INIS)

Racine, Etienne; Buonanno, Alessandra; Kidder, Larry

2009-01-01

We compute the flux of linear momentum carried by gravitational waves emitted from spinning binary black holes at second post-Newtonian (2PN) order for generic orbits. In particular we provide explicit expressions of three new types of terms, namely, next-to-leading order spin-orbit terms at 1.5 post-Newtonian (1.5PN) order, spin-orbit tail terms at 2PN order, and spin-spin terms at 2PN order. Restricting ourselves to quasicircular orbits, we integrate the linear-momentum flux over time to obtain the recoil velocity as function of orbital frequency. We find that in the so-called superkick configuration the higher-order spin corrections can increase the recoil velocity up to a factor ∼3 with respect to the leading-order PN prediction. Whereas the recoil velocity computed in PN theory within the adiabatic approximation can accurately describe the early inspiral phase, we find that its fast increase during the late inspiral and plunge, and the arbitrariness in determining until when it should be trusted, makes the PN predictions for the total recoil not very accurate and robust. Nevertheless, the linear-momentum flux at higher PN orders can be employed to build more reliable resummed expressions aimed at capturing the nonperturbative effects until merger. Furthermore, we provide expressions valid for generic orbits, and accurate at 2PN order, for the energy and angular momentum carried by gravitational waves emitted from spinning binary black holes. Specializing to quasicircular orbits we compute the spin-spin terms at 2PN order in the expression for the evolution of the orbital frequency and found agreement with Mikoczi, Vasuth, and Gergely. We also verified that in the limit of extreme mass ratio our expressions for the energy and angular momentum fluxes match the ones of Tagoshi, Shibata, Tanaka, and Sasaki obtained in the context of black hole perturbation theory.

Space charge effect in SQS transition in a gas counter

International Nuclear Information System (INIS)

Ohgaki, Hideaki; Kametani, Hitoshi; Fujita, Yasuyuki; Uozumi, Yuusuke; Ijiri, Hidenobu; Matoba, Masaru; Sakae, Takeji; Koori, Norihiko

1990-01-01

Systematic investigation of the gas multiplication characteristics in the transition region from proportional to SQS mode in a cylindrical proportional counter has been performed. The property of saturation of the gas multiplication factor can be reproduced using the effective electric field which is corrected for the space charge related to the positive ion density in the avalanche. Photon-mediated gas multiplication can explain the large jump phenomenon of the SQS transition. It is shown that the effective electric field in the avalanche becomes almost zero near the anode surface (Meek's streamer condition) at the 50% transition voltage and the region of its maximum moves slightly away from the anode surface. (orig.)

Counter-intuitive moral judgement following traumatic brain injury.

Science.gov (United States)

Rowley, Dane A; Rogish, Miles; Alexander, Timothy; Riggs, Kevin J

2017-02-07

Several neurological patient populations, including traumatic brain injury (TBI), appear to produce an abnormally 'utilitarian' pattern of judgements to moral dilemmas; they tend to make judgements that maximize the welfare of the majority, rather than deontological judgements based on the following of moral rules (e.g., do not harm others). However, this patient research has always used extreme dilemmas with highly valued moral rules (e.g., do not kill). Data from healthy participants, however, suggest that when a wider range of dilemmas are employed, involving less valued moral rules (e.g., do not lie), moral judgements demonstrate sensitivity to the psychological intuitiveness of the judgements, rather than their deontological or utilitarian content (Kahane et al., Social Cognitive and Affective Neuroscience, 7, 2011, 393). We sought the moral judgements of 30 TBI participants and 30 controls on moral dilemmas where content (utilitarian/deontological) and intuition (intuitive/counter-intuitive) were measured concurrently. Overall TBI participants made utilitarian judgements in equal proportions to controls; disproportionately favouring utilitarian judgements only when they were counter-intuitive, and deontological judgements only when they were counter-intuitive. These results speak against the view that TBI causes a specific utilitarian bias, suggesting instead that moral intuition is broadly disrupted following TBI. © 2017 The British Psychological Society.

Treatment for the recoil effects of the multi-step heavy-ion nucleon transfers with the orthogonalized coupled-reaction-channel theory

International Nuclear Information System (INIS)

Misono, S.; Imanishi, B.

1997-02-01

We have investigated recoil effects in heavy-ion reactions for the nucleon transfers, and the validity of the spatially local approximation for the non-local transfer interaction defined by the orthogonalized coupled-reaction-channel (OCRC) theory. This approximation makes it easier to treat multi-step transfer processes with the coupled channel method and makes it possible to define the nucleon molecular orbitals with the inclusion of the recoil effects. The transfer interaction is expanded in a power series of the momentum operator, and is approximated by the first order term, i.e., the spatially local term. The numerical calculation for the core-symmetric systems 12 C+ 13 C and 16 O+ 17 O with this approximation shows that the recoil effects are well included in the results at energies lower than a few MeV/nucleon. Furthermore, the OCRC formalism allows us even to employ the complete no-recoil approximation for the calculation of cross sections, even though it is not adequate to use this approximation in the distorted wave Born approximation (DWBA) method. As to polarization, however, the no-recoil approximation is not good even in the OCRC formalism. We discuss the recoil effects on nucleon molecular-orbital states. It is shown that states of the covalent molecular orbitals of the valence (transferred) nucleon are little affected by the recoil effects, as already suggested by Korotky et al. in the full finite-range DWBA analysis of the transfer reaction, 13 C( 13 C, 12 C) 14 C. (author). 59 refs

A gas proportional scintillation counter for use in large area detector systems without photomultipliers

International Nuclear Information System (INIS)

Baruch, J.E.F.; Brooke, G.; Kellerman, E.W.; Bateman, J.E.; Connolly, J.F.

1979-01-01

The properties of a prototype gas proportional scintillation (GPS) detector module are described. The module (25X25X14cm 3 ) is intended to form the basic unit of large area (up to approximately 100 m 2 ) calorimetric cosmic ray burst detector. Ionisation from particle tracks in the module is collected onto a point electrode where the GPS signal is generated. A concave mirror focusses this point source onto the end of a fibre optic light guide. In the proposed large area detector these fibres are brought together onto a low light level TV camera which performs the readout. The prototype module has demonstrated an adequate light output for the detection of single muons by such a readout system and also permitted the investigation of the main operating parameters (gas mixture, EHT, pressure, etc) and operational requirements such as proportionality and long term stability. (Auth.)

Detailed Characterization of Nuclear Recoil Pulse Shape Discrimination in the Darkside-50 Direct Dark Matter Experiment

Science.gov (United States)

Ludert, Erin Edkins

While evidence of non-baryonic dark matter has been accumulating for decades, its exact nature continues to remain a mystery. Weakly Interacting Massive Particles (WIMPs) are a well motivated candidate which appear in certain extensions of the Standard Model, independently of dark matter theory. If such particles exist, they should occasionally interact with particles of normal matter, producing a signal which may be detected. The DarkSide-50 direct dark matter experiment aims to detect the energy of recoiling argon atoms due to the elastic scattering of postulated WIMPs. In order to make such a discovery, a clear understanding of both the background and signal region is essential. This understanding requires a careful study of the detector's response to radioactive sources, which in turn requires such sources may be safely introduced into or near the detector volume and reliably removed. The CALibration Insertaion System (CALIS) was designed and built for this purpose in a joint effort between Fermi National Laboratory and the University of Hawaii. This work describes the design and testing of CALIS, its installation and commissioning at the Laboratori Nazionali del Gran Sasso (LNGS) and the multiple calibration campaigns which have successfully employed it. As nuclear recoils produced by WIMPs are indistinguishable from those produced by neutrons, radiogenic neutrons are both the most dangerous class of background and a vital calibration source for the study of the potential WIMP signal. Prior to the calibration of DarkSide-50 with radioactive neutron sources, the acceptance region was determined by the extrapolation of nuclear recoil data from a separate, dedicated experiment, ScENE, which measured the distribution of the pulse shape discrimination parameter, f 90, for nuclear recoils of known energies. This work demonstrates the validity of the extrapolation of ScENE values to DarkSide-50, by direct comparison of the f90 distribution of nuclear recoils from Sc

A Measurement of the Recoil Polarization of Electroproduced Λ(1116)

Energy Technology Data Exchange (ETDEWEB)

McAleer, Simeon B. [Florida State Univ., Tallahassee, FL (United States)

2002-01-01

The CEBAF Large Acceptance Spectrometer at the Thomas Jefferson National Laboratory was used to study the reaction e + p → e' + K⁺ + Λ(1116) for events where Λ(1116) subsequently decayed via the channel Λ(1116) → p + π^-. Data were taken at incident electron beam energies of 2.5, 4.0, and 4.2 GeV during the 1999 E1C run period. They hyperon production spectra span the Q² range from 0.5 to 2.8 GeV² and nearly the entire range in the center of mass angles. The proton angular distribution in the Λ(1116) rest frame is used to deduce the recoil polarization of the hyperon, and the W and cos θ$K+\\atop{cm}$ dependence of the recoil polarization will be presented. The data show sizeable negative polarizations for the Λ(1116) as a function of both cos θ$K+\\atop{cm}$ and W.

The HERMES recoil photon detector and the study of deeply virtual Compton scattering

Energy Technology Data Exchange (ETDEWEB)

Hulse, Charlotte van

2011-03-15

The study of deeply virtual Compton scattering (DVCS) gives information about the contribution of the quark orbital angular momentum to the spin of the proton. DVCS has been studied at the HERMES experiment at DESY in Hamburg. Here 27.6 GeV longitudinally polarized electrons and positrons were scattered off a gaseous proton target. For the analysis of DVCS the recoiling proton could not be detected, but was reconstructed via its missing mass. This method suffers, however, from a 14% background contribution, mainly originating from associated DVCS. In this process the proton does not stay in its ground state but is excited to a {delta}{sup +} resonance. In order to reduce the background contribution down to less than 1%, a recoil detector was installed in the HERMES experiment beginning of 2006. This detector consists of three subcomponents, of which one is the photon detector. The main function of the photon detector is the detection of {delta}{sup +} decay photons. The photon detector was started up and commissioned for the analysis of (associated) DVCS. Subsequently DVCS and associated DVCS were analyzed using the recoil detector. (orig.)

No-recoil approximation to the knock-on exchange potential in the double folding model for heavy-ion collisions

International Nuclear Information System (INIS)

Hagino, K.; Takehi, T.; Takigawa, N.

2006-01-01

We propose the no-recoil approximation, which is valid for heavy systems, for a double folding nucleus-nucleus potential. With this approximation, the nonlocal knock-on exchange contribution becomes a local form. We discuss the applicability of this approximation for elastic scattering of the 6 Li + 40 Ca system. We find that, for this and heavier systems , the no-recoil approximation works as good as another widely used local approximation that employs a local plane wave for the relative motion between the colliding nuclei. We also compare the results of the no-recoil calculations with those of the zero-range approximation often used to handle the knock-on exchange effect

A new recoil distance technique using low energy coulomb excitation in inverse kinematics

Energy Technology Data Exchange (ETDEWEB)

Rother, W., E-mail: wolfram.rother@googlemail.com [Institut fuer Kernphysik der Universitaet zu Koeln, Zuelpicher Str. 77, D-50937 Koeln (Germany); Dewald, A.; Pascovici, G.; Fransen, C.; Friessner, G.; Hackstein, M. [Institut fuer Kernphysik der Universitaet zu Koeln, Zuelpicher Str. 77, D-50937 Koeln (Germany); Ilie, G. [Wright Nuclear Structure Laboratory, Yale University, New Haven, CT 06520 (United States); National Institute of Physics and Nuclear Engineering, P.O. Box MG-6, Bucharest-Magurele (Romania); Iwasaki, H. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 (United States); Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Jolie, J. [Institut fuer Kernphysik der Universitaet zu Koeln, Zuelpicher Str. 77, D-50937 Koeln (Germany); Melon, B. [Dipartimento di Fisica, Universita di Firenze and INFN Sezione di Firenze, Sesto Fiorentino (Firenze) I-50019 (Italy); Petkov, P. [Institut fuer Kernphysik der Universitaet zu Koeln, Zuelpicher Str. 77, D-50937 Koeln (Germany); INRNE-BAS, Sofia (Bulgaria); Pfeiffer, M. [Institut fuer Kernphysik der Universitaet zu Koeln, Zuelpicher Str. 77, D-50937 Koeln (Germany); Pissulla, Th. [Institut fuer Kernphysik der Universitaet zu Koeln, Zuelpicher Str. 77, D-50937 Koeln (Germany); Bundesumweltministerium, Robert-Schuman-Platz 3, D - 53175 Bonn (Germany); Zell, K.-O. [Institut fuer Kernphysik der Universitaet zu Koeln, Zuelpicher Str. 77, D-50937 Koeln (Germany); Jakobsson, U.; Julin, R.; Jones, P.; Ketelhut, S.; Nieminen, P.; Peura, P. [Department of Physics, University of Jyvaeskylae, P.O. Box 35, FI-40014 (Finland); and others

2011-10-21

We report on the first experiment combining the Recoil Distance Doppler Shift technique and multistep Coulomb excitation in inverse kinematics at beam energies of 3-10 A MeV. The setup involves a standard plunger device equipped with a degrader foil instead of the normally used stopper foil. An array of particle detectors is positioned at forward angles to detect target-like recoil nuclei which are used as a trigger to discriminate against excitations in the degrader foil. The method has been successfully applied to measure lifetimes in {sup 128}Xe and is suited to be a useful tool for experiments with radioactive ion beams.

Detailed Characterization of Nuclear Recoil Pulse Shape Discrimination in the DarkSide-50 Direct Dark Matter Experiment

Energy Technology Data Exchange (ETDEWEB)

Edkins, Erin Elisabeth [Univ. of Hawaii, Honolulu, HI (United States)

2017-05-01

While evidence of non-baryonic dark matter has been accumulating for decades, its exact nature continues to remain a mystery. Weakly Interacting Massive Particles (WIMPs) are a well motivated candidate which appear in certain extensions of the Standard Model, independently of dark matter theory. If such particles exist, they should occasionally interact with particles of normal matter, producing a signal which may be detected. The DarkSide-50 direct dark matter experiment aims to detect the energy of recoiling argon atoms due to the elastic scattering of postulated WIMPs. In order to make such a discovery, a clear understanding of both the background and signal region is essential. This understanding requires a careful study of the detector's response to radioactive sources, which in turn requires such sources may be safely introduced into or near the detector volume and reliably removed. The CALibration Insertaion System (CALIS) was designed and built for this purpose in a j oint effort between Fermi National Laboratory and the University of Hawaii. This work describes the design and testing of CALIS, its installation and commissioning at the Laboratori Nazionali del Gran Sasso (LNGS) and the multiple calibration campaigns which have successfully employed it. As nuclear recoils produced by WIMPs are indistinguishable from those produced by neutrons, radiogenic neutrons are both the most dangerous class of background and a vital calibration source for the study of the potential WIMP signal. Prior to the calibration of DarkSide-50 with radioactive neutron sources, the acceptance region was determined by the extrapolation of nuclear recoil data from a separate, dedicated experiment, ScENE, which measured the distribution of the pulse shape discrimination parameter, $f_{90}$, for nuclear recoils of known energies. This work demonstrates the validity of the extrapolation of ScENE values to DarkSide-50, by direct comparison of the $f_{90}$ distributio n of nuclear

Calculations of charged-particle recoils, slowing-down spectra, LET and event-size distributions for fast neutrons and comparisons with measurements

International Nuclear Information System (INIS)

Borak, T.B.; Stinchcomb, T.G.

1979-01-01

A rapid system has been developed for computing charged-particle distributions generated in tissue by any neutron spectra less than 4 MeV. Oxygen and carbon recoils were derived from R-matrix theory, and hydrogen recoils were obtained from cross-section evaluation. Application to two quite different fission-neutron spectra demonstrates the flexibility of this method for providing spectral details of the different types of charged-particle recoils. Comparisons have been made between calculations and measurements of event-size distributions for a sphere of tissue 1 μm in diameter irradiated by these two neutron spectra. LET distributions have been calculated from computed charged-particle recoils and also derived from measurements using the conventional approximation that all charged particles traverse the chamber. The limitations of the approximation for these neutron spectra are discussed. (author)

Use of the helium-3 proportional counter for neutron spectrometry; Utilisation du compteur proportionnel a helium 3 pour la spectrometrie des neutrons

Energy Technology Data Exchange (ETDEWEB)

Vialettes, H; Le Thanh, P [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1967-07-01

Up to now, two methods have been mainly used for neutron spectrometry near nuclear installations: - photographic emulsion spectrometry - the so-called, 'multisphere' technique spectrometry. The first method, which is fairly difficult to apply, has a threshold energy of about 500 keV; this is a big disadvantage for an apparatus which has to be used for spectrometry around nuclear installations where the neutron radiation is very much degraded energetically. The second method does not suffer from this disadvantage but the results which it yields are only approximate. In order to extend the energy range of the neutron spectra studied with sufficient accuracy the use of a helium-3 proportional counter has been considered. This report presents the principles of operation of the helium-3 spectrometer, and the calculation methods which make it possible to take into account the two main effects tending to deform the spectra obtained: - energy absorption by the walls of the counter, - energy loss of the incident neutrons due to elastic collisions with helium-3 nuclei. As an example of the application, the shape of the neutron spectrum emitted by a polonium-lithium source is given; the results obtained are in excellent agreement with theoretical predictions. (authors) [French] Jusqu'ici deux methodes ont ete utilisees principalement pour la spectrometrie des neutrons autour des installations nucleaires: - la spectrometrie par emulsions photographiques - la spectrometrie par la technique dite des multispheres. La premiere methode, d'un emploi assez delicat presente un seuil en energie d'environ 500 keV qui est un obstacle serieux a la spectrometrie autour des installations nucleaires ou le rayonnement neutronique est tres degrade en energie. La deuxieme methode ne presente pas cet inconvenient mais les resultats qu'elle permet d'obtenir ne sont qu'approches. Pour etendre la gamme d'energie des spectres de neutrons etudies avec une precision suffisante, l'utilisation du

First high-statistics and high-resolution recoil-ion data from the WITCH retardation spectrometer

Science.gov (United States)

Finlay, P.; Breitenfeldt, M.; Porobić, T.; Wursten, E.; Ban, G.; Beck, M.; Couratin, C.; Fabian, X.; Fléchard, X.; Friedag, P.; Glück, F.; Herlert, A.; Knecht, A.; Kozlov, V. Y.; Liénard, E.; Soti, G.; Tandecki, M.; Traykov, E.; Van Gorp, S.; Weinheimer, Ch.; Zákoucký, D.; Severijns, N.

2016-07-01

The first high-statistics and high-resolution data set for the integrated recoil-ion energy spectrum following the β^+ decay of 35Ar has been collected with the WITCH retardation spectrometer located at CERN-ISOLDE. Over 25 million recoil-ion events were recorded on a large-area multichannel plate (MCP) detector with a time-stamp precision of 2ns and position resolution of 0.1mm due to the newly upgraded data acquisition based on the LPC Caen FASTER protocol. The number of recoil ions was measured for more than 15 different settings of the retardation potential, complemented by dedicated background and half-life measurements. Previously unidentified systematic effects, including an energy-dependent efficiency of the main MCP and a radiation-induced time-dependent background, have been identified and incorporated into the analysis. However, further understanding and treatment of the radiation-induced background requires additional dedicated measurements and remains the current limiting factor in extracting a beta-neutrino angular correlation coefficient for 35Ar decay using the WITCH spectrometer.

Velocity dependence of transient hyperfine field at Pt ions rapidly recoiling through magnetized Fe

International Nuclear Information System (INIS)

Stuchbery, A.E.; Ryan, C.G.; Bolotin, H.H.

1981-01-01

The velocity-dependence of the transient hyperfine magnetic field acting at nuclei of 196 Pt ions rapidly recoiling through thin magnetized Fe was investigated at a number of recoil velocities. The state of interest (2 1 + ) was populated by Coulomb excitation using beams of 80- and 120-MeV 32 S and 150- and 220-MeV 58 Ni ions. The 2 1 + →0 1 + γ-ray angular distribution precession measurements were carried out in coincidence with backscattered projectiles. From these results, the strength of the transient field acting on Pt ions recoiling through magnetized Fe with average velocities in the extended range 2.14<=v/vsub(o)<=4.82 (vsub(o) = c/137) was found to be consistent with a linear velocity dependence and to be incompatible with the specific vsup(0.45+-0.18) dependence which has been previously reported to account well for all ions in the mass range from oxygen through samarium. This seemingly singular behaviour for Pt and other ions in the Pt mass vicinity is discussed

Scintillation efficiency measurement of Na recoils in NaI(Tl) below the DAMA/LIBRA energy threshold

Energy Technology Data Exchange (ETDEWEB)

Xu, Jingke; Shields, Emily; Calaprice, Frank; Westerdale, Shawn; Froborg, Francis; Suerfu, Burkhant; Alexander, Thomas; Aprahamian, Ani; Back, Henning O.; Casarella, Clark; Fang, Xiao; Gupta, Yogesh K.; Ianni, Aldo; Lamere, Edward; Lippincott, W. Hugh; Liu, Qian; Lyons, Stephanie; Siegl, Kevin; Smith, Mallory; Tan, Wanpeng; Kolk, Bryant Vande

2015-07-01

The dark matter interpretation of the DAMA modulation signal depends on the NaI(Tl) scintillation efficiency of nuclear recoils. Previous measurements for Na recoils have large discrepancies, especially in the DAMA/LIBRA modulation energy region. We report a quenching effect measurement of Na recoils in NaI(Tl) from 3 to 52 keVnr, covering the whole DAMA/LIBRA energy region for dark matter-Na scattering interpretations. By using a low-energy, pulsed neutron beam, a double time-of-flight technique, and pulse-shape discrimination methods, we obtained the most accurate measurement of this kind for NaI(Tl) to date. The results differ significantly from the DAMA reported values at low energies but fall between the other previous measurements. We present the implications of the new quenching results for the dark matter interpretation of the DAMA modulation signal.

The calculated neutron response of a sphere with the multi-counters

International Nuclear Information System (INIS)

Li Taosheng; Yang Lianzhen; Li Dongyu

2004-01-01

Based on the difference of the neutron distribution in the moderator, three position sensitive proportional counters which are perpendicular to each other are inserted into the moderator. The energy responses with six spherical moderators and six incidence directions have been calculated by MCNP4A code. The calculated results for two divided region methods in the radial of the spherical moderator have been analyzed and compared. (authors)

Fabrication and testing of the recoil mass spectrometer at Bombay ...

Indian Academy of Sciences (India)

A recoil mass spectrometer (RMS) has been designed, fabricated and installed ... first order and only mass dispersion is obtained at the focal plane of the ... more details, like, the specifications and a typical beam profile through the ... Further experiments are now in progress to characterize the spectrometer, i.e., to measure.

Radiation loading effect proportional chamber on the performances

International Nuclear Information System (INIS)

Alekseev, T.D.; Kalinina, N.A.; Karpukhin, V.V.; Kruglov, V.V.; Khazins, D.M.

1980-01-01

The effect of a space charge which appears under the effect of radiation loading on counting characteristics of a proportional chamber, is experimentally investigated. Calculations are made which take into account the effect of a space charge of positive ions formed in the chamber. The investigations have been carried out on the test board which consists of a one-coordinate proportional chamber, a telescope of two scintillation counters and a collimated 90 Sr β-source. The proportional chamber has the 160x160 mm dimensions. The signal wires with the 50 μm diameter are located with the step of s=10 mm. High-voltage planes are coiled with a wire with the 100 μm diameter and a 2 mm step. The distance between high-voltage planes are 18 mm. The chamber is blown through with a gaseous mixture, its composition is 57% Ar+38% CH 4 +5% (OCH 3 ) 2 CH 2 . When carrying out measurements in wide ranges, the density of radiation loading and the amplifier threshold are changed. The experimental results show a considerable effect of radiation loading and the value of amplifier threshold on the value of a counting characteristic. This should be taken into account when estimating the performance of a proportional chamber according to board testing using radioactive sources, as conditions for investigations are usually different from those of a physical experiment on an accelerator

Development of precise measurement method of neutron energy for plasma temperature diagnostics in thermonuclear fusion

International Nuclear Information System (INIS)

Mori, Chizuo; Gotoh, Junichi; Uritani, Akira; Miyahara, Hiroshi; Ikeda, Yuichiro; Kasugai, Yoshimi; Kaneko, Junichi

1998-01-01

There are many types of fast neutron spectrometers for plasma temperature diagnostics, 28 Si(n,α) 25 Mg reaction giving the energy resolution of 2.2% for 14 MeV neutrons, the 12 C(n,α) 9 Be reaction giving the resolution of 2.15%. These detectors, however suffer from radiation damage, which demands to exchange the detector to a new one in every a few month depending on the usage. Recoil proton method has also been developed by using liquid scintillator or plastic scintillator, as a neutron-to-proton converter in front of a Si-detector, which is called counter telescope type, giving a resolution of 4.0%. This type of spectrometer can reduce radiation damage by placing Si-detector at outside Neutron beam. The scintillator can measure the lost energy of protons in the converter (i.e. the scintillator) and the measured energy loss can be used for improving the energy resolution. However, the energy resolution of organic scintillator itself is generally not so good. We proposed to use a proportional counter with CH 4 as counting gas and also as a neutron-proton converter, which has far better energy resolution than plastic scintillators, although the time resolution of counting in proportional counters is generally inferior to that in organic scintillation counters. The characteristics of the new spectrometer were experimentally studied and also were simulated with analytical calculation. (author)

Proton compton scattering in the resonance region

International Nuclear Information System (INIS)

Ishii, Takanobu.

1979-12-01

Differential cross sections of the proton Compton scattering have been measured in the energy range between 400 and 1150 MeV at CMS angles of 130 0 , 100 0 and 70 0 . The recoil proton was detected with a magnetic spectrometer using multi-wire proportional chambers and wire spark chambers. In coincidence with the proton, the scattered photon was detected with a lead glass Cerenkov counter of the total absorption type with a lead plate converter, and horizontal and vertical scintillation counter hodoscopes. The background due to the neutral pion photoproduction, was subtracted by using the kinematic relations between the scattered photon and the recoil proton. Theoretical calculations based on an isobar model with two components, that is, the resonance plus background, were done, and the photon couplings of the second resonance region were determined firstly from the proton Compton data. The results are that the helicity 1/2 photon couplings of P 11 (1470) and S 11 (1535), and the helicity 3/2 photon coupling of D 13 (1520) are consistent with those determined from the single pion photoproduction data, but the helicity 1/2 photon coupling of D 13 (1520) has a somewhat larger value than that from the single pion photoproduction data. (author)

Modeling and Measurement of 39Ar Recoil Loss From Biotite as a Function of Grain Dimensions

Science.gov (United States)

Paine, J. H.; Nomade, S.; Renne, P. R.

2004-12-01

The call for age measurements with less than 1 per mil error puts a demand upon geochronologists to be aware of and quantify a number of problems which were previously negligible. One such factor is 39Ar recoil loss during sample irradiation, a phenomenon which is widely assumed to affect only unusually small crystals having exceptionally high surface/volume ratios. This phenomenon has important implications for thermochronologic studies seeking to exploit a range of closure temperatures arising from variable diffusion radii. Our study focuses on biotite, in which spatial isotope distributions cannot be reliably recovered by stepwise heating and which therefore lack recoil-diagnostic age spectrum behavior. Previous work by Renne et al. [Application of a deuteron-deuteron (D-D) neutron generator to 40Ar/39Ar geochronology, Applied Radiation and Isotopes, in press] used the SRIM code to calculate a ˜20% 39Ar recoil loss from the outermost 0.25 μ m of an infinite slab of phyllosillicate. This result is applied to measured grains of the biotite standard GA1550, a hypabyssal granite from the Mount Dromedary Complex, Australia. We measure the thickness and surface area of 166 grains and approximate the shape of each grain as a cylinder. Grain thickness ranges from 3 to 210 μ m, with an average grain radius of 350 μ m. We predict the amount of 39Ar recoil loss from each grain, finding an expected age error >0.1 % for grains thinner than 150 μ m, a >1% error for grain less than 10 μ m thick, and up to a 3% error for grains less than 3 μ m thick. These modeling results will be tested by analysis of the measured grains after irradiation in the Oregon State University TRIGA reactor. It is important to either account for 39Ar loss in thin biotite grains, or use sufficiently thick ones so that recoil loss is negligible. Our results indicate that only biotite grains thicker than 150 μ m should be used for neutron fluence monitoring in order to avoid bias greater than the

The morphology of collision cascades as a function of recoil energy

International Nuclear Information System (INIS)

Heinisch, H.L.; Singh, B.N.

1989-09-01

An analytical method based on defect densities has been devised to determine the threshold energies for subcascade formation in computer simulated collision cascades. Cascades generated with the binary collision code MARLOWE in Al, Cu, Ag, Au, Fe, Mo and W were analyzed to determine the threshold energy for subcascade formation, the number of subcascades per recoil per unit energy and the average spacing of subcascades. Compared on the basis of reduced damage energy, metals of the same crystal structure have subcascade thresholds at the same reduced energy. The number of subcascades per unit reduced damage energy is about the same for metals of the same crystal structure, and the average spacing of subcascades is about the same in units of lattice parameters. Comparisons between subcascade threshold energies and average recoil energies in fission and fusion neutron environments show the spectral sensitivity of the formation of subcascades

Development of a digital trigger system to identify recoil protons at COMPASS-II

Energy Technology Data Exchange (ETDEWEB)

Buechele, Maximilian; Fischer, Horst; Gorzellik, Matthias; Grussenmeyer, Tobias; Herrmann, Florian; Joerg, Philipp; Koenigsmann, Kay; Kremser, Paul; Schopferer, Sebastian [Albert-Ludwigs-Universitaet Freiburg (Germany)

2014-07-01

The GANDALF framework has been developed to deliver a high precision, high performance detector readout and trigger system for particle physics experiments such as the COMPASS-II experiment at CERN. Combining the high performance pulse digitization and feature extraction capabilities of twelve GANDALF modules, each comprising a Virtex-5 SX95T, with the strong computation power of a Virtex-6 SX315T FGPA operated on the TIGER module, we present a digital trigger system for a recoil proton detector. The trigger system was setup and commissioned successfully during a data taking period in 2012. It was mainly used for the calibration of the recoil proton detector and in tagging mode to identify proton tracks online.

A proton-recoil neutron spectrometer for time-dependent ion temperatures on the National Ignition Facility

International Nuclear Information System (INIS)

Murphy, T.J.

1995-01-01

Ion temperatures from inertial confinement fusion targets are usually determined by measuring the Doppler broadening of the neutron spectrum using the time-of-flight method. Measurement systems are generally designed so that the contribution of the duration of neutron production (∼100 ps) to the width of the neutron signal is negligible. This precludes the possibility of time-dependent ion temperature. If, however, one could measure the neutron energy and arrival time at a detector independently, then time-dependent neutron spectra could be obtained, and ion temperature information deduced. A concept utilizing a proton-recoil neutron spectrometer has been developed in which recoil protons from a small plastic foil are measured. From the energy, arrival time, and recoil angle of the recoil proton, the birth time and energy of the incident neutron can be deduced. The sensitivity of the system is low, but the higher anticipated neutron yields from the proposed National Ignition Facility may make the technique feasible. Large scintillator arrays currently in use on the Nova facility for neutron spectral measurements consist of ∼1,000 channels and detect between 50 and 500 counts for typical time-integrated data. Time-dependent results would then require about an order of magnitude larger system. Key issues for making this system feasible will be keeping the cost per channel low while allowing adequately time (∼ 50 ps), energy (20 keV), and angular resolution (2 mrad) for each of the proton detectors

The HERMES recoil detector. Particle identification and determination of detector efficiency of the scintillating fiber tracker

Energy Technology Data Exchange (ETDEWEB)

Lu, Xianguo

2009-11-15

HERMES is a fixed target experiment using the HERA 27.6 GeV polarized electron/positron beams. With the polarized beams and its gas targets, which can be highly polarized, HERMES is dedicated to study the nucleon spin structure. One of its current physics programs is to measure deeply virtual Compton scattering (DVCS). In order to detect the recoiling proton the Recoil Detector was installed in the target region in the winter of 2005, taking data until the HERA-shutdown in the summer of 2007. The Recoil Detector measured energy loss of the traversing particles with its sub-detectors, including the silicon strip detector and the scintillating fiber tracker. This enables particle identification for protons and pions. In this work a systematic particle identification procedure is developed, whose performance is quantified. Another aspect of this work is the determination of the detector efficiency of the scintillating fiber tracker. (orig.)

First β-ν correlation measurement from the recoil-energy spectrum of Penning trapped Ar35 ions

Science.gov (United States)

Van Gorp, S.; Breitenfeldt, M.; Tandecki, M.; Beck, M.; Finlay, P.; Friedag, P.; Glück, F.; Herlert, A.; Kozlov, V.; Porobic, T.; Soti, G.; Traykov, E.; Wauters, F.; Weinheimer, Ch.; Zákoucký, D.; Severijns, N.

2014-08-01

We demonstrate a novel method to search for physics beyond the standard model by determining the β-ν angular correlation from the recoil-ion energy distribution after β decay of ions stored in a Penning trap. This recoil-ion energy distribution is measured with a retardation spectrometer. The unique combination of the spectrometer with a Penning trap provides a number of advantages, e.g., a high recoil-ion count rate and low sensitivity to the initial position and velocity distribution of the ions and completely different sources of systematic errors compared to other state-of-the-art experiments. Results of a first measurement with the isotope Ar35 are presented. Although currently at limited precision, we show that a statistical precision of about 0.5% is achievable with this unique method, thereby opening up the possibility of contributing to state-of-the-art searches for exotic currents in weak interactions.

Digital pulse-shape discrimination applied to an ultra-low-background gas-proportional counting system. First results

International Nuclear Information System (INIS)

Aalseth, C.E.; Day, A.R.; Fuller, E.S.; Hoppe, E.W.; Keillor, M.E.; Mace, E.K.; Myers, A.W.; Overman, C.T.; Panisko, M.E.; Seifert, A.

2013-01-01

A new ultra-low-background proportional counter design was recently developed at Pacific Northwest National Laboratory (PNNL). This design, along with an ultra-low-background counting system which provides passive and active shielding with radon exclusion, has been developed to complement a new shallow underground laboratory (∼30 m water-equivalent) constructed at PNNL. After these steps to mitigate dominant backgrounds (cosmic rays, external gamma-rays, radioactivity in materials), remaining background events do not exclusively arise from ionization of the proportional counter gas. Digital pulse-shape discrimination (PSD) is thus employed to further improve measurement sensitivity. In this work, a template shape is generated for each individual sample measurement of interest, a 'self-calibrating' template. Differences in event topology can also cause differences in pulse shape. In this work, the temporal region analyzed for each event is refined to maximize background discrimination while avoiding unwanted sensitivity to event topology. This digital PSD method is applied to sample and background data, and initial measurement results from a biofuel methane sample are presented in the context of low-background measurements currently being developed. (author)

The application of a microstrip gas counter to energy-dispersive x-ray fluorescence analysis

International Nuclear Information System (INIS)

Veloso, J.F.C.A.; Santos, J.M.F. dos; Conde, C.A.N.

1996-01-01

Performance characteristics of a microstrip gas counter operated as a x-ray fluorescence spectrometer are reported. Gas amplification as a function of microstrip anode-cathode voltage was measured, and the breakdown threshold voltage was determined in pure xenon. The detector temporal stability and the effect of gas purity were assessed. Energy resolution and linearity, detection efficiency, and uniformity of spatial response in the 2- to 60-keV x-ray energy range were determined from the pulse-height distributions of the fluorescence x-ray spectra induced in a variety of single- and multi-element sample materials. Energy resolution similar to conventional proportional counters was achieved at 6 keV

Coincident Auger electron and recoil ion momentum spectroscopy for low-energy ion-atom collisions

International Nuclear Information System (INIS)

Laurent, G.; Tarisien, M.; Flechard, X.; Jardin, P.; Guillaume, L.; Sobocinski, P.; Adoui, L.; Bordenave-Montesquieu, A.; Bordenave-Montesquieu, D.; Chesnel, J.-Y.; Fremont, F.; Hennecart, D.; Lienard, E.; Maunoury, L.; Moretto-Capelle, P.; Cassimi, A.

2003-01-01

The recoil ion momentum spectroscopy (RIMS) method combined with the detection of Auger electrons has been used successfully to analyse double electron capture following O 6+ + He collisions at low impact velocities. Although RIMS and Auger spectroscopies are known to be efficient tools to obtain details on the primary processes occurring during the collision, the conjunction of both techniques provides new insights on the electron capture process. In the present experiment, triple coincidence detection of the scattered projectile, the target recoil ion and the Auger electron allows for a precise identification of the doubly excited states O 4+ (1s 2 nln ' l ' ) populated after double electron-capture events

Determination of the neutron spectrum in the well Naiade attached to the reactor Nereide

International Nuclear Information System (INIS)

Capgras, Andree; Clement, Christophe; Sueur, Maurice.

1977-11-01

The spectral distribution of neutrons in the centre of the well Naiade attached to the Fontenay-aux-Roses reactor Nereide is studied. In the thermal, epithermal and over 2.2 MeV regions, activation detectors are used: 197 Au and 55 Mn (bare and under cadmium), and 58 Ni. In the energy band from a few keV to 2.2 MeV two recoil proton proportional counters are employed. Under these conditions the whole spectrum is studied, but some comments are made on the difficulties of interpreting the results obtained by either of these methods [fr

Neutronic spectrometry measurements in sodium

International Nuclear Information System (INIS)

Perlini, G.; Acerbis, S.

1987-01-01

Measurements were made of neutronic penetration in sodium, which could serve as a reference and as a benchmark for computer codes. The model employed consisted of an assembly of 7 containers full of sodium for a total of 10 tons and a useful length of almost 4 metres. Measurements were performed at various depths along the central axis of the structure with proton recoil proportional counters. The energy band explored was between 100 and 650 keV. Here we report not only the original spectra of the impulses but also the neutronic spectra found by unfolding with the SPEC-4 code

Measurement of the neutron and gamma-ray spectra originating from a 14-MeV neutron source in liquid nitrogen and liquid air

International Nuclear Information System (INIS)

Broecker, B.; Clausen, K.; Schneider-Kuehnle, P.; Weinert, M.

1975-01-01

An experiment to measure the radiation transport originating from a 14-MeV neutron source in liquid nitrogen and liquid air is presented. Neutron and gamma-ray spectra were measured with a proton-recoil NE 213 scintillator and with four spherical proportional counters in a tank filled with liquid nitrogen or liquid air. The neutron spectra cover the energy range of 20 keV to 18 MeV. The source-detector separation varies in the liquid medium between 60 and 240 cm. The experimental setup is briefly described and the errors are estimated. (2 tables, 9 figures) (auth)

Recoil halogen reactions in liquid and frozen aqueous solutions of biomolecules

International Nuclear Information System (INIS)

Arsenault, L.J.; Blotcky, A.J.; Firouzbakht, M.L.; Rack, E.P.; Nebraska Univ., Omaha

1982-01-01

Reactions of recoil 38 Cl, 80 Br and 128 I have been studied in crystalline systems of 5-halouracil, 5-halo-2'-deoxyuridine and 5-halouridine as well as liquid and frozen aqueous solutions of these halogenated biomolecules. In all systems expect crystalline 5-iuodouracil the major product was the radio-labelled halide ion. There was no evidence for other halogen inorganic species. The major labelled organic product was the parent molecule. A recoil atom tracer technique was developed to acquire site information of the biomolecule solutes in the liquid and frozen aqueous systems. For all liquid and frozen aqueous systems, the halogenated biomolecules tended to aggregate. For liquid systems, the tendency for aggregation diminished as the solute concentration approached zero, where the probable state of the solute approached a monomolecular dispersion. Unlike the liquid state, the frozen ice lattice demonstated a ''caging effect'' for the solute aggregates which resulted in constant product yields over the whole concentration range. (orig.)

A study of etching model of alpha-recoil tracks in biotite

International Nuclear Information System (INIS)

Dong Jinquan; Yuan Wanming; Wang Shicheng; Fan Qicheng

2005-01-01

Like fission-track dating, alpha-recoil track (ART) dating is based on the accumulation of nuclear particles that the released from natural radioactivity and produce etchable tracks in solids. ARTs are formed during the alpha-decay of uranium and thorium as well as of their daughter nuclei. When emitting an alpha-particle, the heavy remaining nucleus recoils 30-40 nm, leaving behind a trail of radiation damage. Through etching the ART tracks become visible with the aid of an interference phase-contrast microscope. Under the presupposition that all tracks are preserved since the formation of a sample their total number is a measure of the sample's age. The research for etching model is to accurately determine ART volume density, i.e., the number of ARTs per unit volume. The volume density of many dots in many layers may be determined on a sample using this etching model, and as decreasing the error and increasing the accuracy. (authors)

Neutron electric form factor via recoil polarimetry

International Nuclear Information System (INIS)

Richard Madey; Andrei Semenov; Simon Taylor; Aram Aghalaryan; Erick Crouse; Glen MacLachlan; Bradley Plaster; Shigeyuki Tajima; William Tireman; Chenyu Yan; Abdellah Ahmidouch; Brian Anderson; Razmik Asaturyan; O. Baker; Alan Baldwin; Herbert Breuer; Roger Carlini; Michael Christy; Steve Churchwell; Leon Cole; Samuel Danagoulian; Donal Day; Mostafa Elaasar; Rolf Ent; Manouchehr Farkhondeh; Howard Fenker; John Finn; Liping Gan; Kenneth Garrow; Paul Gueye; Calvin Howell; Bitao Hu; Mark Jones; James Kelly; Cynthia Keppel; Mahbubul Khandaker; Wooyoung Kim; Stanley Kowalski; Allison Lung; David Mack; D. Manley; Pete Markowitz; Joseph Mitchell; Hamlet Mkrtchyan; Allena Opper; Charles Perdrisat; Vina Punjabi; Brian Raue; Tilmann Reichelt; Joerg Reinhold; Julie Roche; Yoshinori Sato; Wonick Seo; Neven Simicevic; Gregory Smith; Samuel Stepanyan; Vardan Tadevosyan; Liguang Tang; Paul Ulmer; William Vulcan; John Watson; Steven Wells; Frank Wesselmann; Stephen Wood; Chen Yan; Seunghoon Yang; Lulin Yuan; Wei-Ming Zhang; Hong Guo Zhu; Xiaofeng Zhu

2003-01-01

The ratio of the electric to the magnetic form factor of the neutron, G En /G Mn , was measured via recoil polarimetry from the quasielastic d((pol-e),e(prime)(pol-n)p) reaction at three values of Q 2 [viz., 0.45, 1.15 and 1.47 (GeV/c) 2 ] in Hall C of the Thomas Jefferson National Accelerator Facility. Preliminary data indicate that G En follows the Galster parameterization up to Q 2 = 1.15 (GeV/c) 2 and appears to rise above the Galster parameterization at Q 2 = 1.47 (GeV/c) 2

Multivariate analysis method for energy calibration and improved mass assignment in recoil spectrometry

International Nuclear Information System (INIS)

El Bouanani, Mohamed; Hult, Mikael; Persson, Leif; Swietlicki, Erik; Andersson, Margaretha; Oestling, Mikael; Lundberg, Nils; Zaring, Carina; Cohen, D.D.; Dytlewski, Nick; Johnston, P.N.; Walker, S.R.; Bubb, I.F.; Whitlow, H.J.

1994-01-01

Heavy ion recoil spectrometry is rapidly becoming a well established analysis method, but the associated data analysis processing is still not well developed. The pronounced nonlinear response of silicon detectors for heavy ions leads to serious limitation and complication in mass gating, which is the principal factor in obtaining energy spectra with minimal cross talk between elements. To overcome the above limitation, a simple empirical formula with an associated multiple regression method is proposed for the absolute energy calibration of the time of flight-energy dispersive detector telescope used in recoil spectrometry. A radical improvement in mass assignment was realized, which allows a more accurate and improved depth profiling with the important feature of making the data processing much easier. ((orig.))

Mixing of phosphorus and antimony ions in silicon by recoil implantation

International Nuclear Information System (INIS)

Kwok, H.L.; Lam, Y.W.; Wong, S.P.; Poon, M.C.

1986-01-01

The effects of mixing phosphorus and antimony ions in silicon by recoil implantation were examined. The electrical properties after ion mixing were investigated, and the results were compared with those obtained using other techniques. Different degrees of activation were also studied, by investigating the annealing behaviour. (U.K.)

Kinematic separation and mass analysis of heavy recoiling nuclei

International Nuclear Information System (INIS)

Oganesyan, Yu.Ts.; Eremin, A.V.; Belozerov, A.V.

2002-01-01

Within the past twelve years, the recoil separator VASSILISSA has been used for investigation of evaporation residues produced in heavy-ion induced complete-fusion reactions. In the course of the experimental work in the region of the elements with 92 ≤ Z ≤ 94, fourteen new isotopes have been identified by the parent-daughter correlations. The study of the decay properties and formation cross sections of the isotopes of elements 110, 112, and 114 was performed with the use of the high intensity 48 Ca beams; 232 Th, 238 U and 242 Pu targets were used in the experiments. At the beam energies corresponding to the calculated cross-section maxima of the 3n evaporation channels, the isotopes 277 110, 283 112, and 287 114 were produced and identified. For further experiments aimed at the synthesis of the superheavy element isotopes (Z ≥ 110) with the intensive 48 Ca extracted beams, the improvements in the ion optical system of the separator and of the focal plane detector system have been made. As a result, for heavy recoiling nuclei with masses A ∼ 250, the mass resolution of about 2.5 % was achieved with a good energy and position resolutions of the focal plane detectors

Range calculations for spallation recoils in ThF4 by use of the computer code 'Marlowe'

International Nuclear Information System (INIS)

Westmeier, W.; Roessler, K.

1978-12-01

The determination of cross sections of spallation reactions requires a knowledge of the target thickness since only the products recoiling from the target are measured and their yield depends on the range. The effective target thickness is a function of the projectile's Z, A and spallation recoil energy and, thus, varies for the individual products. The computer code MARLOWE was used to evaluate energy vs. range curves in the binary collisions approximation. The program was extended to the high energy regime taking into account the stripping of electrons from the projectile and the concomitant changes in the interaction potentials especially for the inelastic part of the collisions. A complementary computer program LATTIC was developed for the parameterization of the lattice description. This code enables the application of MARLOWE to target materials with complicated crystallographic structure. Test calculations for a series of projectile/target combinations showed a reasonable agreement with experimental recoil ranges of Pd, Ag, Os and Ir isotopes from proton induced spallation in Ag, In and Pb targets, respectively. MARLOWE was then applied to calculate product ranges of the 232 Th(p,spall)X-reaction in the ployatomic system ThF 4 . The calculated energy vs. range curves enabled the evaluation of the mean spallation recoil ranges for all possible products, e.g. 170.8 μg/cm 2 for 192 Tl, 115.2 μg/cm 2 for 208 At and 37.1 μg/cm 2 for 223 Ac. (orig.)

Detection of low momentum protons with the new HERMES recoil detector

Energy Technology Data Exchange (ETDEWEB)

Vilardi, Ignazio

2008-10-15

In this theis the recoil detector for the HERMES experiment at HERA is described. It consists of a silicon strip detector, a scintillating fiber tracker, and a photon detector for the {delta}{sup +} background rejection, all surrounded by a superconducting 1 Tesla solenoid. Results of cosmic ray tests are presented. (HSI)

Detection of low momentum protons with the new HERMES recoil detector

International Nuclear Information System (INIS)

Vilardi, Ignazio

2008-10-01

In this theis the recoil detector for the HERMES experiment at HERA is described. It consists of a silicon strip detector, a scintillating fiber tracker, and a photon detector for the Δ + background rejection, all surrounded by a superconducting 1 Tesla solenoid. Results of cosmic ray tests are presented. (HSI)

Recoil corrected bag model calculations for semileptonic weak decays

International Nuclear Information System (INIS)

Lie-Svendsen, Oe.; Hoegaasen, H.

1987-02-01

Recoil corrections to various model results for strangeness changing weak decay amplitudes have been developed. It is shown that the spurious reference frame dependence of earlier calculations is reduced. The second class currents are generally less important than obtained by calculations in the static approximation. Theoretical results are compared to observations. The agreement is quite good, although the values for the Cabibbo angle obtained by fits to the decay rates are somewhat to large

High energy neutron recoil scattering from liquid 4He

International Nuclear Information System (INIS)

Holt, R.S.; Needham, L.M.; Paoli, M.P.

1987-10-01

The neutron recoil scattering from liquid 4 He at 4.2 K and 1.6 K has been observed for a momentum transfer of 150 A -1 using the Electron Volt Spectrometer on the pulsed neutron source, ISIS. The experiment yielded mean atomic kinetic energy values = 14.8 +- 3 K at 4.2 K and = 14.6 +- 3.2 K at 1.6 K in good agreement with values obtained at lower momentum transfers. (author)

Coincident Auger electron and recoil ion momentum spectroscopy for low-energy ion-atom collisions

Energy Technology Data Exchange (ETDEWEB)

Laurent, G. E-mail: glaurent@ganil.fr; Tarisien, M.; Flechard, X.; Jardin, P.; Guillaume, L.; Sobocinski, P.; Adoui, L.; Bordenave-Montesquieu, A.; Bordenave-Montesquieu, D.; Chesnel, J.-Y.; Fremont, F.; Hennecart, D.; Lienard, E.; Maunoury, L.; Moretto-Capelle, P.; Cassimi, A

2003-05-01

The recoil ion momentum spectroscopy (RIMS) method combined with the detection of Auger electrons has been used successfully to analyse double electron capture following O{sup 6+} + He collisions at low impact velocities. Although RIMS and Auger spectroscopies are known to be efficient tools to obtain details on the primary processes occurring during the collision, the conjunction of both techniques provides new insights on the electron capture process. In the present experiment, triple coincidence detection of the scattered projectile, the target recoil ion and the Auger electron allows for a precise identification of the doubly excited states O{sup 4+} (1s{sup 2}nln{sup '}l{sup '}) populated after double electron-capture events.

In-situ, real-time, studies of film growth processes using ion scattering and direct recoil spectroscopy techniques.

Energy Technology Data Exchange (ETDEWEB)

Smentkowski, V. S.

1999-04-22

Time-of-flight ion scattering and recoil spectroscopy (TOF-ISARS) enables the characterization of the composition and structure of surfaces with 1-2 monolayer specificity. It will be shown that surface analysis is possible at ambient pressures greater than 3 mTorr using TOF-ISARS techniques; allowing for real-time, in situ studies of film growth processes. TOF-ISARS comprises three analytical techniques: ion scattering spectroscopy (ISS), which detects the backscattered primary ion beam; direct recoil spectroscopy (DRS), which detects the surface species recoiled into the forward scattering direction; and mass spectroscopy of recoiled ions (MSRI), which is 3 variant of DRS capable of isotopic resolution for all surface species--including H and He. The advantages and limitations of each of these techniques will be discussed. The use of the three TOF-ISARS methods for real-time, in situ film growth studies at high ambient pressures will be illustrated. It will be shown that MSRI analysis is possible during sputter deposition. It will be also be demonstrated that the analyzer used for MSRI can also be used for time of flight secondary ion mass spectroscopy (TOF-SIMS) under high vacuum conditions. The use of a single analyzer to perform the complimentary surface analytical techniques of MSRI and SIMS is unique. The dwd functionality of the MSRI analyzer provides surface information not obtained when either MSRI or SIMS is used independently.

Chemical reactions of recoil atoms and thermal atoms of tritium with haloid benzenes

International Nuclear Information System (INIS)

Simirskij, Yu.N.; Firsova, L.P.

1978-01-01

Radiochemical yields have been determined for the products of substitution of hydrogen atoms and halides in Cl-, Br-, and I-benzenes with tritium atoms obtained during thermal dissociation of T 2 and with recoil atoms T arising in nuclear reaction 6 Li(n, P)T. It is shown that in the series of Cl-, Br-, and I-benzenes yields of the products of substitution of halides atoms with tritium grow, whereas those of hydrogen atom substitution change only little. The correlation nature of the yields of substitution products of halide atoms with tritium remains constant in a wide range of the initial kinetic energies of T atoms for the recoil atoms with E 0 =2.7 MeV and for the completely thermolized atoms during thermal dissociation of T 2

Recoil and conversion electron considerations of the {sup 166}Dy/{sup 166}Ho in vivo generator

Energy Technology Data Exchange (ETDEWEB)

Zeevaart, J.R. [North-West Univ., Mmabatho (South Africa). CARST; Szuecs, Z. [Nesca (South African Nuclear Energy Corporation Ltd.), Pretoria (South Africa). Radiochemistry; Hungarian Academy of Sciences, Debrecen (Hungary). Inst. of Nuclear Research; Takacs, S.; Jarvis, N. [Hungarian Academy of Sciences, Debrecen (Hungary). Inst. of Nuclear Research; Jansen, D. [Nesca (South African Nuclear Energy Corporation Ltd.), Pretoria (South Africa). Radiochemistry

2012-07-01

The use of radionuclides as potential therapeutic radiopharmaceuticals is increasingly investigated. An important aspect is the delivery of the radionuclide to the target, i.e. the radionuclide is not lost from the chelating agent. For in vivo generators, it is not only the log K of complexation between the metal ion and the chelator that is important, but also whether the daughter radionuclide stays inside the chelator after decay of the parent radionuclide. In our previous work, we showed that the classical recoil effect is only applicable for decays with a Q value higher than 0.6 MeV (in the atomic mass range around 100). However, Zhernosekov et al. published a result for {sup 140}Nd/{sup 140}Pr (Q = 0.222 MeV) which indicated that > 95% of the daughter ({sup 140}Pr) was lost by a DOTA chelator upon decay of {sup 140}Nd. The authors ascribed this to the ''post-effect''. Their experiment was repeated with the {sup 166}Dy/{sup 166}Ho generator to ascertain whether our calculations were correct. It was found that 72% of the daughter ({sup 166}Ho) was liberated from the DOTA chelator, indicating that the 'post effect' does exist in contrast to our recoil calculations. Upon further investigation, we determined that one should not only consider recoil energy levels but also the mode of decay which was able to explain the partial recoil found for {sup 166}Dy/{sup 166}Ho. It is concluded for the {sup 166}Dy/{sup 166}Ho system that the low recoil energy of the daughter nucleus {sup 166}Ho is not a sufficient reason to rule out release of the nuclide from chelators. On the other hand, we found that the ratio of the {sup 166}Ho that gets released corresponds to the ratio of relaxation of Ho atoms via the Auger process. (orig.)

Direct mass measurements of light neutron-rich nuclei using fast recoil spectrometers

International Nuclear Information System (INIS)

Vieira, D.J.; Wouters, J.M.

1987-01-01

Extensive new mass measurement capabilities have evolved with the development of recoil spectrometers. In the Z = 3 to 9 neutron-rich region alone, 12 neutron-rich nuclei have been determined for the first time by the fast-recoil direct mass measurement method. A recent experiment using the TOFI spectrometer illustrates this technique. A systematic investigation of nuclei that lie along or near the neutron-drip line has provided a valuable first glimpse into the nuclear structure of such nuclei. No evidence for a large single-particle energy gap at N = 14 is observed; however, a change in the two-neutron separation model calculations, and is interpreted in terms of the smaller 1s/sub 1/2/ - 1s/sub 1/2/ interaction compared to that of the 0d/sub 5/2/ - 0d/sub 5/2/ neutron-neutron interaction. 18 refs., 7 figs., 1 tab

Emanation of /sup 232/U daughter products from submicrometer particles of uranium oxide and thorium dioxide by nuclear recoil and inert gas diffusion

Energy Technology Data Exchange (ETDEWEB)

Coombs, M.A.; Cuddihy, R.G. (Lovelace Biomedical and Environmental Research Inst., Albuquerque, NM (USA). Inhalation Toxicology Research Inst.)

1983-01-01

Emanation of /sup 232/U daughter products by nuclear recoil and inert gas diffusion from spherical, submicrometer particles of uranium oxide and thorium dioxide was studied. Monodisperse samples of particles containing 1% /sup 232/U and having physical diameters between 0.1 and 1 ..mu..m were used for the emanation measurements. Thorium-228 ions recoiling from the particles after alpha-decay of /sup 232/U were collected electrostatically on a recoil cathode. Radon-220 diffusing from the particles was swept by an airstream into a 4 l. chamber where the /sup 220/Rn daughters were collected on a second cathode. Mathematical models of radionuclide emanation from spherical particles were used to calculate the recoil range of /sup 228/Th and the diffusion coefficient of /sup 220/Rn in the particle matrix. A /sup 228/Th recoil range of 0.02 ..mu..m and a /sup 220/Rn diffusion coefficient of 3 x 10/sup -14/ cm/sup 2//sec were obtained in both uranium oxide and thorium dioxide particles.

Space and power efficient hybrid counters array

Science.gov (United States)

Gara, Alan G [Mount Kisco, NY; Salapura, Valentina [Chappaqua, NY

2009-05-12

A hybrid counter array device for counting events. The hybrid counter array includes a first counter portion comprising N counter devices, each counter device for receiving signals representing occurrences of events from an event source and providing a first count value corresponding to a lower order bits of the hybrid counter array. The hybrid counter array includes a second counter portion comprising a memory array device having N addressable memory locations in correspondence with the N counter devices, each addressable memory location for storing a second count value representing higher order bits of the hybrid counter array. A control device monitors each of the N counter devices of the first counter portion and initiates updating a value of a corresponding second count value stored at the corresponding addressable memory location in the second counter portion. Thus, a combination of the first and second count values provide an instantaneous measure of number of events received.

Properties enhancement and recoil loop characteristics for hot deformed nanocrystalline NdFeB permanent magnets

International Nuclear Information System (INIS)

Liu, Z. W.; Huang, Y. L.; Hu, S. L.; Zhong, X. C.; Yu, H. Y.; Gao, X. X.

2013-01-01

Nanocrystalline NdFeB magnets were prepared by spark plasma sintering (SPS) and SPS followed by HD using melt spun ribbons as the starting materials. The microstructure of SPSed and HDed magnets were analyzed. The effects of process including temperature and compression ratio on the microstructure and properties were investigated. High magnetic properties were obtained in anisotropic HDed magnets. The combination of Zn and Dy additions was successfully employed to improve the coercivity and thermal stability of the SPSed magnets. Open recoil loops were found in these magnets with Nd-rich composition and without soft magnetic phase for the first time. The relationship between the recoil loops and microstructure for SPS and HD NdFeB magnets were investigated. The investigations showed that the magnetic properties of SPS+HDed magnets are related to the extent of the aggregation of Nd-rich phase, which was formed during HD due to existence of porosity in SPSed precursor. Large local demagnetization fields induced by the Nd-rich phase aggregation leads to the open loops and significantly reduced the coercivity. By reducing the recoil loop openness, the magnetic properties of HDed NdFeB magnets were successfully improved. (author)

Characterisation of a ultra-miniature counter for microdosimetric measurements in a therapeutic 400 MeV/A carbon beam

International Nuclear Information System (INIS)

Endo, S.; Takada, M.; Ishikawa, M.; Hoshi, M.; Uehara, S.; Yamaguchi, H.; Kanai, T.; Matsufji, N.; Shizuma, K.; Onizuka, Y.

2002-01-01

Single event spectra of a clinical carbon beam have been measured by an ultra-miniature tissue-equivalent proportional counter (UMC). In order to cover the energy range of the Bragg peak, the incident energy of the carbon beam was degraded by aluminium plates. Single event spectra for carbon-events incident to the UMC were analysed and selected at several carbon energies using thin scintillation counters. It was found that the dose weighted lineal energy distributions have a doublet peak structure due to incident carbon beam and fragment contributions. (author)

A low-level needle counter

International Nuclear Information System (INIS)

Fujita, Y.; Taguchi, Y.; Imamura, M.; Inoue, T.; Tanaka, S.

1977-01-01

A small end-window type gas-flow counter which has a sharpened needle (anode) against the end-window plane (cathode) was developed for low-level counting of β particles to the amount of less than one count per hour in solid sources of relatively high specific activity. The advantage of the needle counter for low-level work is that being of a conical shape the active volume as against the window area is small. The background count rate of 0.0092+-0.0005 cpm was obtained for a 10 mm dia needle counter operating in GM mode and in anticoincidence with a well-type NaI(Tl) guard crystal with massive shields. The counter design and the counter characteristics are presented in detail. The needle counter is simple in design, low-cost and stable in long time operation. (author)

Energy Reduction Multipath Routing Protocol for MANET Using Recoil Technique

Directory of Open Access Journals (Sweden)

Rakesh Kumar Sahu

2018-04-01

Full Text Available In Mobile Ad-hoc networks (MANET, power conservation and utilization is an acute problem and has received significant attention from academics and industry in recent years. Nodes in MANET function on battery power, which is a rare and limited energy resource. Hence, its conservation and utilization should be done judiciously for the effective functioning of the network. In this paper, a novel protocol namely Energy Reduction Multipath Routing Protocol for MANET using Recoil Technique (AOMDV-ER is proposed, which conserves the energy along with optimal network lifetime, routing overhead, packet delivery ratio and throughput. It performs better than any other AODV based algorithms, as in AOMDV-ER the nodes transmit packets to their destination smartly by using a varying recoil off time technique based on their geographical location. This concept reduces the number of transmissions, which results in the improvement of network lifetime. In addition, the local level route maintenance reduces the additional routing overhead. Lastly, the prediction based link lifetime of each node is estimated which helps in reducing the packet loss in the network. This protocol has three subparts: an optimal route discovery algorithm amalgamation with the residual energy and distance mechanism; a coordinated recoiled nodes algorithm which eliminates the number of transmissions in order to reduces the data redundancy, traffic redundant, routing overhead, end to end delay and enhance the network lifetime; and a last link reckoning and route maintenance algorithm to improve the packet delivery ratio and link stability in the network. The experimental results show that the AOMDV-ER protocol save at least 16% energy consumption, 12% reduction in routing overhead, significant achievement in network lifetime and packet delivery ratio than Ad hoc on demand multipath distance vector routing protocol (AOMDV, Ad hoc on demand multipath distance vector routing protocol life

High-energy elastic recoil detection heavy ions for light element analysis

International Nuclear Information System (INIS)

Goppelt-Langer, P.; Yamamoto, S.; Takeshita, H.; Aoki, Y.; Naramoto, H.

1994-01-01

The detection of light and medium heavy elements in not homogeneous solids is a severe problem in ion beam analysis. Heavy elements can be detected by the well established Rutherford backscattering technique (RBS). In a homogeneous host material most impurities can be easily analyzed by secondary ion mass spectroscopy (SIMS). Some isotopes ( 3 He, 6 Li, 10 B) can be measured by nuclear reaction analysis (NRA) using thermal neutrons inducing (n, p) or (n, α) reactions. Others can be detected by energetic ion beams by nuclear reactions (e.g. 15 N( 1 H, αγ) 12 C for analysis of hydrogen). A high content of H, D or T can be also determined by elastic recoil detection using an energetic He beam. The latter technique has been developed to a universal method for detection of light and heavy elements in any target, using a high energetic heavy ion beam and a detector system, which is able to identify the recoils and delivers energy and position of the particles. (author)

Black hole radiation in the brane world and the recoil effect

International Nuclear Information System (INIS)

Frolov, Valeri; Stojkovic, Dejan

2002-01-01

A black hole attached to a brane in a higher-dimensional space emitting quanta into the bulk may leave the brane as a result of a recoil. We study this effect. We consider black holes which have a size much smaller than the characteristic size of extra dimensions. Such a black hole can be effectively described as a massive particle with internal degrees of freedom. We consider an interaction of such particles with a scalar massless field and prove that for a special choice of the coupling constant describing the transition of the particle to a state with smaller mass the probability of massless quanta emission takes the form identical to the probability of the black hole emission. Using this model we calculate the probability for a black hole to leave the brane and study its properties. The discussed recoil effect implies that, for black holes which might be created in the interaction of high energy particles in colliders, the thermal emission of the formed black hole could be terminated and the energy nonconservation can be observed in brane experiments

Boiling crisis as inhibition of bubble detachment by the vapor recoil force

International Nuclear Information System (INIS)

Nikolayev, V.S.; Beysens, D.; Garrabos, Y.

2004-01-01

Boiling crisis is a transition between nucleate and film boiling. In this communication we present a physical model of the boiling crisis based on the vapor recoil effect. Our numerical simulations of the thermally controlled bubble growth at high heat fluxes show how the bubble begins to spread over the heater thus forming a germ for the vapor film. The vapor recoil force not only causes the vapor spreading, it also creates a strong adhesion to the heater that prevents the bubble departure, thus favoring the further bubble spreading. Near the liquid-gas critical point, the bubble growth is very slow and allows the kinetics of the bubble spreading to be observed. Since the surface tension is very small in this regime, only microgravity conditions can preserve a convex bubble shape. Under such conditions, we observed an increase of the apparent contact angle and spreading of the dry spot under the bubble, thus confirming our model of the boiling crisis. (authors)

A long liquid Cherenkov counter for 300 to 460 MeV/c pion beams

International Nuclear Information System (INIS)

Zavrtanik, D.; Sever, F.; Plesko, M.; Music, M.; Kernel, G.

1984-01-01

A long liquid Cherenkov counter has been used to measure the proportion of muons in positive and negative pion beams in the momentum range between 300 and 460 MeV/c. A nine-parameter function fits all the spectra well. The data show a smooth dependence on incident momenta and agree with calculations of pion and muon pulse heights. (orig.)

Counter-discourse in Zimbabwean literature

NARCIS (Netherlands)

Mangena, Tendai

2015-01-01

Counter-Discourse in Zimbabwean Literature is a study of specific aspects of counter-discursive Zimbabwean narratives in English. In discussing the selected texts, my thesis is based on Terdiman’s (1989) the postcolonial concept of counter-discourse. In Zimbabwean literature challenges to a dominant

D-Brane Recoil Mislays Information

CERN Document Server

Ellis, Jonathan Richard; Nanopoulos, Dimitri V

1998-01-01

We discuss the scattering of a light closed-string state off a $D$ brane, taking into account quantum recoil effects on the latter, which are described by a pair of logarithmic operators. The light-particle and $D$-brane subsystems may each be described by a world-sheet with an external source due to the interaction between them. This perturbs each subsystem away from criticality, which is compensated by dressing with a Liouville field whose zero mode we interpret as time. The resulting evolution equations for the $D$ brane and the closed string are of Fokker-Planck and modified quantum Liouville type, respectively. The apparent entropy of each subsystem increases as a result of the interaction between them, which we interpret as the loss of information resulting from non-observation of the other entangled subsystem. We speculate on the possible implications of these results for the propagation of closed strings through a dilute gas of virtual $D$ branes.

Measurement of neutron energy spectra of PuO[sub 2]-UO[sub 2] mixed oxide fuel and penetrated through surrounding lead-acryl shield

Energy Technology Data Exchange (ETDEWEB)

Nakao, Noriaki; Tsujimura, Norio; Nakamura, Takashi (Tohoku Univ., Sendai (Japan). Cyclotron and Radioisotope Center); Momose, Takumaro; Ninomiya, Kazushige; Ishiguro; Hideharu

1993-12-01

The energy spectra of neutrons emitted from an aluminum can containing PuO[sub 2]-UO[sub 2] mixed oxide fuel and penetrated through a 35mm thick lead-acryl shield surrounding the can, were measured with the NE-213 organic liquid scintillator, the proton recoil proportional counter and the multi-moderator [sup 3]He spectrometer (Bonner Ball). The measured results were compared with the results calculated by the MORSE-CG Monte Carlo code on the basis of source neutron yields obtained by the ORIGEN-2 code and the source energy spectrum cited from the reference data. The agreement between these two was pretty good. The dose equivalents were then calculated from thus-obtained energy spectra and the flux-to-dose conversion factor and showed good agreement with the data measured with the neutron dose-equivalent counters (rem counters). Since the published data on energy spectrum of mixed oxide fuel are very scarce, these results can be useful as basic data for shielding design study and radiation control of nuclear fuel facilities. (author).

Model-independent evaluation of recoils channeling impact on visible energy spectra in dark matter particles crystalline detectors

International Nuclear Information System (INIS)

Dyuldya, S.V.; Bratchenko, M.I.

2012-01-01

Proposed is a direct method of Dark Matter crystalline scintillation detectors calibration by means of an atomistic molecular dynamics modeling of their responses to ∼10 keV recoil atoms. Simulations show that the recoils channeling exists in NaI lattice with probabilities of ∼5 - 15 %. It does not affect the mean values of quenching factors but gives rise to high visible energy spectral tails absent in disordered detectors. As a result, the lattice ordering manifests the ∼100 % effect on NaI(Tl) visible energy spectra at 2-6 keV window

Penetration of HEPA filters by alpha recoil aerosols

International Nuclear Information System (INIS)

McDowell, W.J.; Seeley, F.G.; Ryan, M.T.

1976-01-01

Tests at Oak Ridge National Laboratory confirmed that alpha-emitting particulate matter does penetrate high-efficiency filter medium, identical to that used in HEPA filters, much more effectively than do non-radioactive or beta-gamma active aerosols. Filter retention efficiencies drastically lower than the 99.97 percent quoted for ordinary particulate matter have been observed with 212 Pb, 253 Es, and 238 Pu sources, indicating that the phenomenon is common to all of these and probably to all alpha-emitting materials of appropriate half-life. Results with controlled air-flow through filters in series are consistent with the picture of small particles dislodged from the ''massive'' surface of an alpha-active material, and then repeatedly dislodged from positions on the filter fibers, by the alpha recoils. The process shows only a small dependence on the physical form of the source material. Oxide dust, nitrate salt, and plated metal all seem to generate the recoil particles effectively. The amount penetrating a series of filters depends on the total amount of activity in the source material, its specific activity, and the length of time of air flow. Dependence on the air flow velocity is slight. It appears that this phenomenon has not been observed in previous experiments with alpha-active aerosols because the tests did not continue for a sufficiently long time. A theoretical model of the process has been developed, amenable to computer handling, that should allow calculation of the rate constants associated with the transfer through and release of radioactive material from a filter system by this process

Efficiency simulation of long neutron counter

International Nuclear Information System (INIS)

Hu Qingyuan; Li Bojun; Zhang De; Guo Hongsheng; Wang Dong; Yang Gaozhao; Si Fenni; Liu Jian

2008-01-01

In order to achieve the high efficiency and uniform sensitivity for neutrons with widely different energies, the efficiency of long boron trifluoride proportional counter imbedded in polyethylene moderator was simulated by MCNP code. The result shows that detective efficiency would increase with increasing moderator radius and response curve at higher energy would be ameliorated through adjusting the thickness of front moderator. Also we calculated the relative efficiencies for different energy of a detector whose efficiencies were calibrated on an accelerator. The simulated efficiency for D-D neutrons (2.4 MeV) is 75% of the efficiency for D-T neutrons (14.1 MeV), which is approximately agreed with experimental data, 61%. The validity of the simulated model was proved by the consistent results between calculation and experiment data. (authors)

Recoil effect on β-decaying in vivo generators, interpreted for 103Pd/103mRh

International Nuclear Information System (INIS)

Szucs, Zoltan; Rooyen, Johann van; Zeevaart, Jan Rijn

2009-01-01

The use of Auger emitters as potential radiopharmaceuticals is being increasingly investigated. One of the radionuclides of interest is 103m Rh, which can be produced from 103 Ru or 103 Pd in an in vivo generator. A potential problem, however, is the recoil of the 103m Rh out of the carrier molecule and even out of the target cell. In order to determine the likelihood of this happening in the 103 Pd/ 103m Rh, case calculations were made to prove that this does not happen. The equations were generalised for all radionuclides with an atomic mass of 10-240 as a tool for determining the recoil threshold of any β-emitting radionuclide.

Efficiency determination of whole-body counters by Monte Carlo method, using a microcomputer

International Nuclear Information System (INIS)

Fernandes Neto, J.M.

1987-01-01

A computing program using Monte Carlo method for calculate the whole efficiency of distributed radiation counters in human body is developed. A simulater of human proportions was used, of which was filled with a known and uniform solution containing a quantity of radioisopes. The 99m Tc, 131 I and 42 K were used in this experience, and theirs activities compared by a liquid scintillator. (C.G.C.) [pt

Microbeam recoil detection for hydration of minerals studies

Energy Technology Data Exchange (ETDEWEB)

Sie, S.H.; Suter, G.F. [CSIRO, North Ryde, NSW (Australia). Exploration and Mining Div.; Chekhmir, A.; Green, T.H. [Macquarie Univ., North Ryde, NSW (Australia)

1993-12-31

The glancing angle geometry is chosen to enable application of the elastic recoil detection microanalysis on thick geological samples, for hydrogen content determination. Simultaneous PIXE measurements can be used to eliminate the problem of uncertainties in beam charge collection. The method is applied to determine the hydration characteristics of silicates, produced experimentally at high pressure and temperature simulating the lower crust and upper mantle conditions. Preliminary results show that the technique can be applied readily on a microscopic (<100 {mu}m) scale for determination of H at fraction of atomic percent level. 9 refs., 3 figs.

Microbeam recoil detection for hydration of minerals studies

Energy Technology Data Exchange (ETDEWEB)

Sie, S H; Suter, G F [CSIRO, North Ryde, NSW (Australia). Exploration and Mining Div.; Chekhmir, A; Green, T H [Macquarie Univ., North Ryde, NSW (Australia)

1994-12-31

The glancing angle geometry is chosen to enable application of the elastic recoil detection microanalysis on thick geological samples, for hydrogen content determination. Simultaneous PIXE measurements can be used to eliminate the problem of uncertainties in beam charge collection. The method is applied to determine the hydration characteristics of silicates, produced experimentally at high pressure and temperature simulating the lower crust and upper mantle conditions. Preliminary results show that the technique can be applied readily on a microscopic (<100 {mu}m) scale for determination of H at fraction of atomic percent level. 9 refs., 3 figs.

Precision lifetime measurements using the recoil distance method

International Nuclear Information System (INIS)

Kruecken, R.

2000-01-01

The recoil distance method (RDM) for the measurements of lifetimes of excited nuclear levels in the range from about 1 ps to 1,000 ps is reviewed. The New Yale Plunger Device for RDM experiments is introduced and the Differential Decay Curve Method for their analysis is reviewed. Results from recent RDM experiments on SD bands in the mass-190 region, shears bands in the neutron deficient lead isotopes, and ground state bands in the mass-130 region are presented. Perspectives for the use of RDM measurements in the study of neutron-rich nuclei are discussed

Precision Lifetime Measurements Using the Recoil Distance Method

Science.gov (United States)

Krücken, R.

2000-01-01

The recoil distance method (RDM) for the measurements of lifetimes of excited nuclear levels in the range from about 1 ps to 1000 ps is reviewed. The New Yale Plunger Device for RDM experiments is introduced and the Differential Decay Curve Method for their analysis is reviewed. Results from recent RDM experiments on SD bands in the mass-190 region, shears bands in the neutron deficient lead isotopes, and ground state bands in the mass-130 region are presented. Perspectives for the use of RDM measurements in the study of neutron-rich nuclei are discussed. PMID:27551587

Recoil generated radiotracers in studies of molecular dynamics

International Nuclear Information System (INIS)

Spicer, L.D.

1981-01-01

This chapter summarizes many of the contributions that the recoil technique of generating excited radiotracer atoms in the presence of a thermal environment is making to the field of chemical dynamics. Specific topics discussed critically include characterization of the generation and behavior of excited molecules including fragmentation kinetics and energy transfer, measurement of thermal and hot kinetic parameters, and studies of reaction mechanisms and stereochemistry as a function of reaction energy. Distinctive features that provide unique approaches to dynamical problems are evaluated in detail and the complementarity with more conventional techniques is addressed. Prospects for future applications are also presented

Production and measurement of dispersion aerosols; application to the transport of deuteron-induced and 84Kr-induced reaction recoils

International Nuclear Information System (INIS)

Schmidt-Ott, W.-D.; Dincklage, R.-D. von

1977-01-01

Dispersion aerosols were produced from various fluids and mixed with helium, nitrogen, and air. The diameter of the aerosols was estimated from their deflection in a low density micro-jet. These two-phase flows were tested for their transport performance for recoils of deuteron-induced reactions at the Goettingen cyclotron. Transport yields of 70%, 90% and 86% were measured when using n-decane with helium, nitrogen, and air, respectively. In comparison to the earlier use of ethylene the amount of disturbing activity induced on the gases was much smaller. The effect of aerosol formation by condensation is discussed. The system was applied in electron- and γ-ray spectroscopy of deuteron-induced reaction recoils. The mixture of n-decane and helium was used for the transport of 84 Kr-induced reaction recoils at the Darmstadt UNILAC. (Auth.)

The parallel plate avalanche counter: a simple, rugged, imaging X-ray counter

International Nuclear Information System (INIS)

Joensen, K.D.; Budtz-Joergensen, C.; Bahnsen, A.; Madsen, M.M.; Olesen, C.; Schnopper, H.W.

1995-01-01

A two-dimensional parallel gap proportional counter has been developed at the Danish Space Research Institute. Imaging over the 120 mm diameter active area is obtained using the positive ion component of the avalanche signals as recorded by a system of wedge- and strip-electrodes. An electronically simple, but very effective background rejection is obtained by using the fast electron component of the avalanche signal. Gas gains up to 8x10 5 have been achieved. An energy-resolution of 16% and a sub-millimeter spatial resolution have been measured at 5.9 keV for an operating gas gain of 10 5 . In principle, the position coordinates are linear functions of electronic readouts. The present model, however, exhibits non-linearities, caused by imperfections in the wedge and strip-electrode pattern. These non-linearities are corrected by using a bilinear correction algorithm. We conclude that the rugged construction, the simple electronics, the effectiveness of the background rejection and the actual imaging performance makes this a very attractive laboratory detector for low and intermediate count rate imaging applications. ((orig.))

An audiovisual feedback device for compression depth, rate and complete chest recoil can improve the CPR performance of lay persons during self-training on a manikin

International Nuclear Information System (INIS)

Krasteva, Vessela; Jekova, Irena; Didon, Jean-Philippe

2011-01-01

This study aims to contribute to the scarce data available about the abilities of untrained lay persons to perform hands-only cardio-pulmonary resuscitation (CPR) on a manikin and the improvement of their skills during training with an autonomous CPR feedback device. The study focuses on the following questions: (i) Is there a need for such a CPR training device? (ii) How adequate are the embedded visual feedback and audio guidance for training of lay persons who learn and correct themselves in real time without instructor guidance? (iii) What is the achieved effect of only 3 min of training? This is a prospective study in which 63 lay persons (volunteers) received a debriefing to basic life support and then performed two consecutive 3 min trials of hands-only CPR on a manikin. The pre-training skills of the lay persons were tested in trial 1. The training process with audio guidance and visual feedback from a cardio compression control device (CC-Device) was recorded in trial 2. After initial debriefing for correct chest compressions (CC) with rate 85–115 min −1 , depth 3.8–5.4 cm and complete recoil, in trial 1 the lay persons were able to perform CC without feedback at mean rate 95.9 ± 18.9 min −1 , mean depth 4.13 ± 1.5 cm, with low proportions of 'correct depth', 'correct rate' and 'correct recoil' at 33%, 43%, 87%, resulting in the scarce proportion of 14% for compressions, which simultaneously fulfill the three quality criteria ('correct all'). In trial 2, the training process by the CC-Device was established by the significant improvement of the CC skills until the 60th second of training, when 'correct depth', 'correct rate' and 'correct recoil' attained the plateau of the highest quality at 82%, 90%, 96%, respectively, resulting in 73% 'correct all' compressions within 3 min of training. The training was associated with reduced variance of the mean rate 102.4 ± 4

What is Counter-Enlightenment?

OpenAIRE

Darrin M. McMahon

2017-01-01

This article counters recent suggestions that there was no such thing as a “Counter-Enlightenment” or “Counter-Enlightenments,” and that such terms ought thus to be abandoned.   While acknowledging inevitable difficulties with the terms, the article argues that there can be no doubting the reality.   European countries faced a variety of vehement and self-conscious movements that defined themselves precisely through their opposition to what they took to be the corrosive effects of the Enlight...

A portable neutron coincidence counter

Energy Technology Data Exchange (ETDEWEB)

Peurrung, A.J.; Bowyer, S.M.; Craig, R.A.; Dudder, G.B.; Knopf, M.A.; Panisko, M.E.; Reeder, P.L.; Stromswold, D.C.; Sunberg, D.S.

1996-11-01

Pacific Northwest National Laboratory has designed and constructed a prototype portable neutron coincidence counter intended for use in a variety of applications, such as the verification and inspection of weapons components, safety measurements for novel and challenging situations, portable portal deployment to prevent the transportation of fissile materials, uranium enrichment measurements in hard-to-reach locations, waste assays for objects that cannot be measured by existing measurement systems, and decontamination and decommissioning. The counting system weighs less than 40 kg and is composed of parts each weighing no more than 5 kg. In addition, the counter`s design is sufficiently flexible to allow rapid, reliable assembly around containers of nearly arbitrary size and shape. The counter is able to discern the presence of 1 kg of weapons-grade plutonium within an ALR-8 (30-gal drum) in roughly 100 seconds and 10 g in roughly 1000 seconds. The counter`s electronics are also designed for maximum adaptability, allowing operation under a wide variety of circumstances, including exposure to gamma-ray fields of 1 R/h. This report provides a detailed review of the design and construction process. Finally, preliminary experimental measurements that confirm the performance capabilities of this counter are discussed. 6 refs., 18 figs., 3 tabs.

Effects of recoil-implanted oxygen on depth profiles of defects and annealing processes in P{sup +}-implanted Si studied using monoenergetic positron beams

Energy Technology Data Exchange (ETDEWEB)

Uedono, Akira; Moriya, Tsuyoshi; Tanigawa, Shoichiro [Tsukuba Univ., Ibaraki (Japan). Inst. of Materials Science; Kitano, Tomohisa; Watanabe, Masahito; Kawano, Takao; Suzuki, Ryoichi; Ohdaira, Toshiyuki; Mikado, Tomohisa

1996-04-01

Effects of oxygen atoms recoiled from SiO{sub 2} films on depth profiles of defects and annealing processes in P{sup +}-implanted Si were studied using monoenergetic positron beams. For an epitaxial Si specimen, the depth profile of defects was found to be shifted toward the surface by recoil implantation of oxygen atoms. This was attributed to the formation of vacancy-oxygen complexes and a resultant decrease in the diffusion length of vacancy-type defects. The recoiled oxygen atoms stabilized amorphous regions introduced by P{sup +}-implantation, and the annealing of these regions was observed after rapid thermal annealing (RTA) at 700degC. For a Czochralski-grown Si specimen fabricated by through-oxide implantation, the recoiled oxygen atoms introduced interstitial-type defects upon RTA below the SiO{sub 2}/Si interface, and such defects were dissociated by annealing at 1000degC. (author)

CEDAR counter (internal part)

CERN Multimedia

CERN PhotoLab

1976-01-01

Here on the mounting bench. The counter is a differential Cerenkov, corrected for chromaticity, able to differentiate pions from kaons up to 350 GeV. Counters of this type were used in all SPS hadron beams.

Whole Body Counters (rev.)

Energy Technology Data Exchange (ETDEWEB)

Woodburn, John H. [Walter Johnson High School, Rockville, MD; Lengemann, Frederick W. [Cornell University

1967-01-01

Whole body counters are radiation detecting and measuring instruments that provide information about the human body. This booklet describes different whole body counters, scientific principles that are applied to their design, and ways they are used.

Determination of the extraction efficiency for {sup 233}U source α-recoil ions from the MLL buffer-gas stopping cell

Energy Technology Data Exchange (ETDEWEB)

Wense, Lars v.d.; Seiferle, Benedict; Thirolf, Peter G. [Ludwig-Maximilians-Universitaet Muenchen, Garching (Germany); Laatiaoui, Mustapha [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); Helmholtz Institut Mainz, Mainz (Germany)

2015-03-01

Following the α decay of {sup 233}U, {sup 229}Th recoil ions are shown to be extracted in a significant amount from the MLL buffer-gas stopping cell. The produced recoil ions and subsequent daughter nuclei are mass purified with the help of a customized quadrupole mass spectrometer. The combined extraction and mass purification efficiency for {sup 229}Th{sup 3+} is determined via MCP-based measurements and via the direct detection of the {sup 229}Th α decay. A large value of (10±2)% for the combined extraction and mass purification efficiency of {sup 229}Th{sup 3+} is obtained at a mass resolution of about 1u/e. In addition to {sup 229}Th, also other α-recoil ions of the {sup 233,} {sup 232}U decay chains are addressed. (orig.)

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)

Calibration tests and use of a Nicolet/Xentronics imaging proportional chamber mounted on a conventional source for protein crystallography

Energy Technology Data Exchange (ETDEWEB)

Derewenda, Z; Helliwell, J R

1989-04-01

The results are presented of calibration tests and several single-crystal X-ray data collection experiments undertaken with a Nicolet/Xentronics Imaging Proportional Counter mounted on a conventional X-ray source. Considerable attention has been given to system optimization in collaboration with Nicolet, and this has led to a performance of high quality. (orig.).

Over-the-Counter Medicines

Science.gov (United States)

Over-the-counter (OTC) medicines are drugs you can buy without a prescription. Some OTC medicines relieve aches, pains and itches. ... medicine is safe enough to sell over-the-counter. Taking OTC medicines still has risks. Some interact ...

In-vivo radiation counter

International Nuclear Information System (INIS)

Pollard, D.E.

1983-01-01

This patent specification describes a radiation counter utilizing at least one detector for sensing radiation from a living body. The radiation counter also includes an aperture for forming a corridor between the body and the detector. A shield outside the corridor prevents passage of background radiation through the corridor and gaining access to the detector. The counter also includes a device for isolating a selected portion of the body from the corridor such that radiation counting is restricted to a region of the body through a separate detector. The corridor formation permits a user to stand in an upright position while the detector and detectors are able to separately monitor different sections of the body. The radiation counter overcomes the problem of obtaining accurate and quick measurements or radiation doses sustained by a large group of persons. (author)

Experiments with a magnetic separator for heavy recoil ions

International Nuclear Information System (INIS)

Mosler, E.

1981-01-01

Using a triple-focusing (position and momentum), crescent-shaped separator for heavy recoil-ions different experiments were performed. The improvement consists in the enhancement of the transmission from 8% to 25% for 500 keV recoil ions from the reaction 238 U(α, 3n)sup(239m)Pu. For sup(237m)Pu the electromagnetic decay of the 1.1 μs shape isomer into the 82 ns shape isomer was searched for. The upper limit for gamma decay is 1.25 +- 1.25% for Esub(γ) = 200 keV and for electron decay 0.29 +- 0.29% in comparison to isomeric fission. The upper limit for interband transitions is 2.5% (2 delta), from which the upper limit of the partial half-life for the electromagnetic decay of the 1.1 μs isomer is calculated to 44 μs. Due to the performed interpretation the spin difference between both isomers extends at least to ΔI = 3. For sup(238m)U the back-decay into the 1. minimum by the EO-transition and the converted 2 + → 0 + transition in the first decay and the decay by alpha articles was looked for both in single measurements as in a coincidence measurement to L-X-ray quanta. The upper limits are GAMMAsub(EO) = 2.0, GAMMAsub(α)/GAMMAsub(F) = 0.4 and GAMMA(back-decay)/GAMMAsub(F) approx. equal to 100. (orig./HSI) [de

Rapid actinide analysis method coupling liquid chromatography/ICP-MS and "9"0Sr gas proportional counter in post-accidental situation environmental samples

International Nuclear Information System (INIS)

Habibi, Azza

2015-01-01

The present study follows the Fukushima power plant accident and aimed to develop an analytical method to achieve, during an emergency situation, a rapid identification and quantification of alpha and beta emitters in environmental samples. The first step of this study allowed us to list the alpha and beta emitters which can be released in the environment in case of a nuclear accident. The second step aimed towards the development of a rapid analysis method to quantify 17 radionuclides of U, Th, Pu, Am, Np and Sr. The main objective was the automation of the radiochemical separation step and its coupling for the measurement. The separation is performed using columns containing extraction resins, namely TEVA, TRU and Sr. The measurement is performed using an ICP-MS (inductively coupled plasma mass spectrometry) and in some cases a gas proportional counter to quantify radiostrontium ("8"9Sr and "9"0Sr). Excellent figures of merit were obtained, off line, with water (tap, river and sea water) and solid matrices (soil and aerosol filters), after a micro-wave digestion or an alkaline fusion dissolution followed by a Ca_3(PO_4)_2 coprecipitation. The proposed analytical strategy showed yields between 70 % and 100 % and standard deviations between 5 % and 10 %. The newly developed separation method was then automated and coupled on-line to ICP-MS. The operating parameters were optimized using a design of experiments and the results were processed with Minitab. The optimized automated separation coupled on-line to the ICP-MS allows the rapid quantification, in 1.5 h per sample, of U, Th, Pu, Am, Np and Sr with detection limits gain as high as 20 times for artificial radionuclide. (author)

Velocity dependence of enhanced dynamic hyperfine field for Pd ions swiftly recoiling in magnetized Fe

International Nuclear Information System (INIS)

Stuchbery, A.E.; Ryan, G.C.; Bolotin, H.H.; Sie, S.H.

1980-01-01

The velocity-dependence of the magnitude of the enchanced dynamic hyperfine magnetic field (EDF) manifest at nuclei of 108 Pd ions swiftly recoiling through thin magnetized Fe has been investigated at ion velocities higher than have heretofore been examined for the heavier nuclides (i.e., at initial recoil velocities (v/Zv 0 )=0.090 and 0.160, v 0 =c/137). These results for 108 Pd, when taken in conjunction with those of prior similar measurements for 106 Pd at lower velocities, and fitted to a velocity dependence for the EDF, give for the Pd isotopes over the extended velocity range 1.74 0 )<=7.02, p=0.41+-0.15; a result incompatible with previous attributions of a linear velocity dependence for the field

Recent results from the chemistry of recoiling carbon and silicon atoms: The interplay between hot atom chemistry and gas kinetics

International Nuclear Information System (INIS)

Gaspar, P.P.; Garmestani, K.; Ferrieri, R.A.; Wolf, A.P.

1990-01-01

Recent results from the chemistry of recoiling carbon and silicon atoms illustrate the power of an experimental approach to the solution of complex mechanistic problems that combines the study of the reactions of recoiling atoms with conventional gas kinetic techniques. Included will be the reactions of 11 C atoms with anisole, addressing the question whether an aromatic pi-electron system can compete as a reactive site with carbon-hydrogen bonds

Effect of γ-exposure on retention of recoil 56Mn in permanganates

International Nuclear Information System (INIS)

Mishra, S.P.; Vijaya

2002-01-01

Full text: γ-exposure effect on recombination of recoil 56 Mn atom in La, Sr and Ba permanganates were studied with a special emphasis to pre-and post-activation γ-ray irradiation treatment using 60 Co source. Permanganates were inactivated by ionizing radiation as a function of γ-dose without neutron irradiation, however, pronounced effects were seen after neutron activation. Pre-irradiation increase the initial retention and promotes the annealing phenomenon as the introduction of defect into the lattice though on the other hand radiolytic phenomenon may also appear. Pre-activated sample gave higher retention value for lanthanum and barium permanganates in comparison to strontium permanganate at different γ-doses for desired period of gamma annealing than those obtained at corresponding γ-doses for similar length of time in case of post-activated targets. Kinetics of annealing by γ-radiolytic effects follow first order rate law. The observed results are discussed in the light of existing ideas for understanding the recoil stabilization phenomenon of parent reformation and the nature of precursors in permanganates

Mass and energy dispersive recoil spectrometry of GaAs structures

International Nuclear Information System (INIS)

Hult, M.

1994-01-01

Mass and energy dispersive Recoil Spectrometry (RS) using heavy ions at energies of about 0.2Α-0.8Α MeV has attracted much interest recently due to its potential for separately and unambiguously generating information on isotopic depth distributions. The principal advantages of mass and energy dispersive RS are that both light and heavy elements can be separately studied simultaneously and problems caused by chemical matrix effects are avoided since the technique is based on high energy nucleus-nucleus scattering. In order to elucidate reactions taking place in various GaAs structures, Time of flight-Energy (ToF-E) RS was developed to allow Ga and As to be studied separately down to depths of about 500-800 nm with a depth resolution of about 16 nm at the surface. This was shown in a study of an Al x Ga 1-x As quantum-well structure. The benefits of using ToF-E RS on GaAs structures were further demonstrated in studies of Co/GaAs and CoSi 2 /GaAs reactions, as well as in a study of the composition of MOCVD grown Al x Ga 1-x As. Most recoil measurements employed 127 I at energies of about 50-90 MeV as projectiles. The recoil detector telescope consisted of a silicon energy detector and two carbon foil time pick-off detectors separated by a variable flight length of 213.5-961 mm. The reactions taking place between various thin films and GaAs were also studied using complementary techniques such as XRD, XPS and SEM. Co was found to react extensively with GaAs, already at about 300 degrees C, making it unsuitable as a contact material. Thin films of Co and Si were found to react extensively with each other and to form CoSi 2 at 500 degrees C and above. CoSi 2 , a low resistivity silicide, turned out to be stable on GaAs, at least up to 700 degrees C. Considerable grain growth could cause problems, however, in the use of CoSi 2 -contacts. 112 refs, figs, tabs

Three-dimensional recoil-ion momentum analyses in 8.7 MeV O7+-He collisions

International Nuclear Information System (INIS)

Kambara, T.; Tang, J.Z.; Awaya, Y.

1995-01-01

Using high-resolution recoil-ion momentum spectroscopy we have measured the differential cross sections of single-electron capture and target single-ionization processes for 8.7 MeV O 7+ -He collisions as functions of scattering angle. A transverse momentum resolution of ±0.2 au, which corresponds to an angular resolution of about ±1.5x10 -6 rad for the projectile scattering angle, was obtained by intersecting a well collimated O 7+ beam with a target of a supersonic He jet from a pre-cooled gas and by measuring the recoil-ion transverse momentum. For the single capture reaction, information on the n-value of the electron final state in O 6+ (1snl) is obtained from the longitudinal momentum of the recoil ions. In pure single-electron capture, the dominant contributions to capture were found to be those from the n=4 and higher states, whereas single capture accompanied by the ionization of the second target electron mainly populates n=2 to n=4 states. Furthermore, the measured transverse momentum distribution differs significantly between pure single capture and capture with simultaneous ionization. The measured data for the pure capture process compare favourably with theoretical results based on a molecular-state expansion method. Other experimental data are discussed in terms of the classical overbarrier model. (author)

Permanently calibrated interpolating time counter

International Nuclear Information System (INIS)

Jachna, Z; Szplet, R; Kwiatkowski, P; Różyc, K

2015-01-01

We propose a new architecture of an integrated time interval counter that provides its permanent calibration in the background. Time interval measurement and the calibration procedure are based on the use of a two-stage interpolation method and parallel processing of measurement and calibration data. The parallel processing is achieved by a doubling of two-stage interpolators in measurement channels of the counter, and by an appropriate extension of control logic. Such modification allows the updating of transfer characteristics of interpolators without the need to break a theoretically infinite measurement session. We describe the principle of permanent calibration, its implementation and influence on the quality of the counter. The precision of the presented counter is kept at a constant level (below 20 ps) despite significant changes in the ambient temperature (from −10 to 60 °C), which can cause a sevenfold decrease in the precision of the counter with a traditional calibration procedure. (paper)

Use of the on-line Moessbauer effect as a contribution to the study of recoil defects in solids

International Nuclear Information System (INIS)

Jeandey, Christian

1974-01-01

This research thesis addresses the study of effects of nuclear reactions, also known as 'after-effects' such as atomic disorders resulted from atom recoil, but also possible chemical modifications. The author more particularly focuses of recoil defects. He reports a critical review of studies of structure defects (in pure metals, ordered alloys, ionic crystals) performed by using conventional resonance absorption, and then presents an analysis of results of the defect creation dynamics as it had been proposed by other authors. He also proposes an overview of the evolution and disappearance of defects during thermal treatments. After a review of experiments based on the on-line Moessbauer effect, the author reports the study of recoil effects in pure metals (iron, hafnium), in alloys (Fe 1-x Al x , FeGe 2 , cubic, monoclinic and hexagonal FeGe), and in organic complexes (ferrous oxalate, different types of hafnium chelate, hafnium oxide). He finally discusses the electronic properties of different types of iron and hafnium chelate in solid phase [fr

Portable microcomputer controlled radiation counter

International Nuclear Information System (INIS)

Mason, E.W.; Weber, J.M.

1984-01-01

A portable microcomputer controlled counter for use as a radiation counter is described. The counter uses digital processing of input pulses from a radiation detector. The number of counts received by the microcomputer per unit time is used to calculate a value for display using a calibration factor obtained during physical calibration of the instrument with a radiation source or with a pulse generator. The keyboard is used to enter calibration points. The number of calibration points which may be entered depends on the degree of accuracy desired by the user. The high voltage generator which drives the detector is triggered by pulses from the microcomputer in relation to the count rate. After processing the count, the resulting count rate or dose rate is displayed on the liquid crystal display. The counter is autoranging in which the decimal point is shifted as necessary by the microcomputer. The units displayed are determined by the user by means of a multiposition switch. Low battery and an overrange condition are displayed. An interface is provided via a connector to allow parallel transmission of data to peripheral devices. Low battery power consumption is featured. The counter is capable of providing more accurate readings than currently available counters

Energy performance of an innovative liquid desiccant dehumidification system with a counter-flow heat and mass exchanger using potassium formate

DEFF Research Database (Denmark)

Jradi, Muhyiddine; Riffat, Saffa

2014-01-01

An innovative micro-scale liquid desiccant dehumidification system is numerically investigated. The liquid desiccant dehumidification unit employs a counter-flow low-cost and efficient heat and mass exchange core, improving the thermal performance and eliminating desiccant carryover...... that the dehumidifier effectiveness is directly proportional to the intake air temperature, intake air relative humidity and liquid desiccant flow rate where the effectiveness is inversely proportional to the intake air velocity and the heat exchanger air channel height....

Probing the structure of unstable nuclei through the recoiled proton tagged knockout reaction

International Nuclear Information System (INIS)

Ye, Y.; Cao, Z.; Jiang, D.

2010-01-01

Recoiled proton tagged knockout reaction experiments were carried-out for 8 He at 82,5 MeV/u in RIKEN and for 6 He at 65 MeV/u in Lanzhou. The very preliminary results for the distinguish of the reaction mechanism are presented and compared to the kinematics calculation. (authors)

Sub-recoil cooling up to nano-Kelvin. Direct measurement of spatial coherency length. New tests for Levy statistics

International Nuclear Information System (INIS)

Saubamea, B.

1998-12-01

This thesis presents a new method to measure the temperature of ultracold atoms from the spatial autocorrelation function of the atomic wave-packets. We thus determine the temperature of metastable helium-4 atoms cooled by velocity selective dark resonance, a method known to cool the atoms below the temperature related to the emission or the absorption of a single photon by an atom at rest, namely the recoil temperature. This cooling mechanism prepares each atom in a coherent superposition of two wave-packets with opposite mean momenta, which are initially superimposed and then drift apart. By measuring the temporal decay of their overlap, we have access to the Fourier transform of the momentum distribution of the atoms. Using this method, we can measure temperatures as low as 5 nK, 800 times as small as the recoil temperature. Moreover we study in detail the exact shape of the momentum distribution and compare the experimental results with two different theoretical approaches: a quantum Monte Carlo simulation and an analytical model based on Levy statistics. We compare the calculated line shape with the one deduced from simulations, and each theoretical model with experimental data. A very good agreement is found with each approach. We thus demonstrate the validity of the statistical model of sub-recoil cooling and give the first experimental evidence of some of its characteristics: the absence of steady-state, the self-similarity and the non Lorentzian shape of the momentum distribution of the cooled atoms. All these aspects are related to the non ergodicity of sub-recoil cooling. (author)

Pulse-shape discrimination between electron and nuclear recoils in a NaI(Tl) crystal

International Nuclear Information System (INIS)

Lee, H.S.; Adhikari, G.; Adhikari, P.; Choi, S.; Hahn, I.S.

2015-01-01

We report on the response of a high light-output NaI(Tl) crystal to nuclear recoils induced by neutrons from an Am-Be source and compare the results with the response to electron recoils produced by Compton-scattered 662 keV γ-rays from a 137 Cs source. The measured pulse-shape discrimination (PSD) power of the NaI(Tl) crystal is found to be significantly improved because of the high light output of the NaI(Tl) detector. We quantify the PSD power with a quality factor and estimate the sensitivity to the interaction rate for weakly interacting massive particles (WIMPs) with nucleons, and the result is compared with the annual modulation amplitude observed by the DAMA/LIBRA experiment. The sensitivity to spin-independent WIMP-nucleon interactions based on 100 kg⋅year of data from NaI detectors is estimated with simulated experiments, using the standard halo model.

Pulse-shape discrimination between electron and nuclear recoils in a NaI(Tl) crystal

Energy Technology Data Exchange (ETDEWEB)

Lee, H.S. [Department of Physics, Ewha Womans University,Seoul 120-750 (Korea, Republic of); Adhikari, G.; Adhikari, P. [Department of Physics, Sejong University,Seoul 143-747 (Korea, Republic of); Choi, S. [Department of Physics and Astronomy, Seoul National University,Seoul 151-747 (Korea, Republic of); Hahn, I.S. [Department of Science Education, Ewha Womans University,Seoul 120-750 (Korea, Republic of)

2015-08-18

We report on the response of a high light-output NaI(Tl) crystal to nuclear recoils induced by neutrons from an Am-Be source and compare the results with the response to electron recoils produced by Compton-scattered 662 keV γ-rays from a {sup 137}Cs source. The measured pulse-shape discrimination (PSD) power of the NaI(Tl) crystal is found to be significantly improved because of the high light output of the NaI(Tl) detector. We quantify the PSD power with a quality factor and estimate the sensitivity to the interaction rate for weakly interacting massive particles (WIMPs) with nucleons, and the result is compared with the annual modulation amplitude observed by the DAMA/LIBRA experiment. The sensitivity to spin-independent WIMP-nucleon interactions based on 100 kg⋅year of data from NaI detectors is estimated with simulated experiments, using the standard halo model.

Process for the automatic compensation of spectral displacement based on quenching processes in a liquid scintillation counter

International Nuclear Information System (INIS)

Nather, R.E.

1978-01-01

In measurements in a liquid scintillation counter, the tritium or C 14 isotope to be examined is situated in a scintillator solution. It is excited according to the energy of the β particle to emit light. An electrical signal is proportional to the light signal, and from the former, selective counting in the β spectrum can be undertaken in an impulse height analyser. The influence of the quenching effects by colour quenching or chemical quenching would reduce the gain of the counter. To compensate for the displacement of the spectrum, the required adjustment of a system parameter is carried out by calibration with a sample of low quenching effect. The calibration process is directly set for the energy end-point of the spectrum. Well known processes can be used to determine the quenching effect of the quenching represented by the sample. For example, the system parameters can be the discriminator level of the counter window. (DG) 891 HP [de

What is Counter-Enlightenment?

Directory of Open Access Journals (Sweden)

Darrin M. McMahon

2017-02-01

Full Text Available This article counters recent suggestions that there was no such thing as a “Counter-Enlightenment” or “Counter-Enlightenments,” and that such terms ought thus to be abandoned.   While acknowledging inevitable difficulties with the terms, the article argues that there can be no doubting the reality.   European countries faced a variety of vehement and self-conscious movements that defined themselves precisely through their opposition to what they took to be the corrosive effects of the Enlightenment.  In the process, they defined the main terms of an enduring vision of the world that we now associate with the Right.

Automatic detection of recoil-proton tracks and background rejection criteria in liquid scintillator-micro-capillary-array fast neutron spectrometer

Science.gov (United States)

Mor, Ilan; Vartsky, David; Dangendorf, Volker; Tittelmeier, Kai.; Weierganz, Mathias; Goldberg, Mark Benjamin; Bar, Doron; Brandis, Michal

2018-06-01

We describe an analysis procedure for automatic unambiguous detection of fast-neutron-induced recoil proton tracks in a micro-capillary array filled with organic liquid scintillator. The detector is viewed by an intensified CCD camera. This imaging neutron detector possesses the capability to perform high position-resolution (few tens of μm), energy-dispersive transmission-imaging using ns-pulsed beams. However, when operated with CW or DC beams, it also features medium-quality spectroscopic capabilities for incident neutrons in the energy range 2-20 MeV. In addition to the recoil proton events which display a continuous extended track structure, the raw images exhibit complex ion-tracks from nuclear interactions of fast-neutrons in the scintillator, capillaries quartz-matrix and CCD. Moreover, as expected, one also observes a multitude of isolated scintillation spots of varying intensity (henceforth denoted "blobs") that originate from several different sources, such as: fragmented proton tracks, gamma-rays, heavy-ion reactions as well as events and noise that occur in the image-intensifier and CCD. In order to identify the continuous-track recoil proton events and distinguish them from all these background events, a rapid, computerized and automatic track-recognition-procedure was developed. Based on an appropriately weighted analysis of track parameters such as: length, width, area and overall light intensity, the method is capable of distinguishing a single continuous-track recoil proton from typically surrounding several thousands of background events that are found in each CCD frame.

Analysis of hard exclusive scattering processes of the HERMES recoil experiment

International Nuclear Information System (INIS)

Brodski, Irina

2014-11-01

Deeply virtual Compton Scattering (DVCS), ep → epγ is the simplest reaction giving indication of generalized parton distributions (GPD) of the nucleon. The DVCS process has the same final state as the Bethe-Heitler process (BH). For this reason the access is taken not through the cross-sections directly but through asymmetries between DVCS events depending on charge and polarization of the 27.6 GeV beam. For the first time the azimuthal asymmetry amplitudes according the charge of the lepton beam are extracted using a kinematically complete reconstruction method at the HERMES experiment. The recoil detector installed in 2006 allows the reconstruction of recoiling protons that completes the measurements of the forward detector to cover almost the complete angle range around the vertex. This approach allows suppressing the background processes by almost a complete magnitude compared to the traditional method using only the information of the forward spectrometer. The analysis of the asymmetries was carried out at different values of the kinematic variables t c' x B and Q 2 to investigate the dependence of these variables. This work pushes the limits of the readability of data and shows which periods have been found to be unstable in the data acquisition. It points out the impact of this finding to previous HERMES publications.

Nuclear timer/counter

International Nuclear Information System (INIS)

Wuthayavanich, S.

1978-01-01

This thesis represents the development of a Timer/COUNTER compatible to the standard Nuclear Instrument Module Specifications. The unit exhibits high accuracy, light weight and ease of maintenance. The unit also has a built-in precision discriminator to discriminate unwanted signals that may cause interference in counting. With line frequency time base the timer can be preset in steps from 0.1 sec. to 9 x 10 5 min. The counter with six digits miniature display and an overflow output has a maximum counting rate of 10 MHz. The accumulated counting data can be transferred to a teletype or printer for hard copy printout with the aid of ORTEC 777 Line Printer or 432 A Print-out Control or any print out interface with input compatible to the print output of the Timer/Counter. Owing to its NIM compatibility the unit is directly powered by the NIM power supply

Chemical effects of /sup 32/P recoil atom

Energy Technology Data Exchange (ETDEWEB)

Matsuura, N [Tokyo Univ. (Japan). Coll. of General Education

1975-06-01

Szilard-Chalmers' effect of /sup 32/P were reviewed. The concentration method using Szilard-Chalmers' effect in production of radioisotope, circumstances such as exposure time in an atomic pile, states of target substances and the yields by them were discussed. Many kinds of chemical effects, such as chemical effects of /sup 32/P recoil atom in phosphorated glass, studies of the effect of adducts, the threshold of ..gamma..-ray effect, the oxidation number of /sup 32/P in phosphorated glass by exposure time in the pile and the labelling position of /sup 32/P, are associated with caryotransformation (nuclear transformation) by environmental factors. The abovementioned articles were explained concerning /sup 32/P.

The G_E/G_M-ratio of the proton by recoil polarization measurement in e+parrow e'+p

Science.gov (United States)

Punjabi, Vina; Jones, Mark; Perdrisat, Charles F.; Quemener, Gilles

1998-10-01

The recently commissioned Hall A high resolution spectrometers (HRS) and the focal plane polarimeter (FPP) were used to obtain the ratio of the electric and magnetic form factors of the proton, G_E/G_M. This form factor ratio is proportional to the measured ratio of the transverse, P_t, to longitudinal, P_l, components of the recoiling proton polarization. The method takes advantage of the precession of the proton magnetic moment in the hadron HRS, which rotates the longitudinal polarization component into the plane of the FPP analyzer; this allows simultaneous measurement of both components of the polarization. The ratio P_t/P_l is independent of both the electron beam polarization and the polarimeter analyzing power. Most of the data were obtained with polarized beams of 100 μ A with polarization of ~ 0.39 incident on the 15 cm cell of the high power LH2 target. We will report the results for G_E/GM at several values of Q^2 between 0.5 and 3.5 GeV^2.

The first CEDAR counter

CERN Multimedia

CERN PhotoLab

1976-01-01

The first differential Cerenkov counter with chromatic corrections (called CEDAR) successfully tested at the PS in July 75. These counters were used in the SPS hadronic beams for particle identification. Some of the eight photomultipliers can be seen: they receive the light reflected back through the annular diaphragm. René Maleyran stands on the left.

CDMS Detector Fabrication Improvements and Low Energy Nuclear Recoil Measurements in Germanium

Energy Technology Data Exchange (ETDEWEB)

Jastram, Andrew [Texas A & M Univ., College Station, TX (United States)

2015-12-01

As the CDMS (Cryogenic Dark Matter Search) experiment is scaled up to tackle new dark matter parameter spaces (lower masses and cross-sections), detector production efficiency and repeatability becomes ever more important. A dedicated facility has been commissioned for SuperCDMS detector fabrication at Texas A&M University (TAMU). The fabrication process has been carefully tuned using this facility and its equipment. Production of successfully tested detectors has been demonstrated. Significant improvements in detector performance have been made using new fabrication methods, equipment, and tuning of process parameters. This work has demonstrated the capability for production of next generation CDMS SNOLAB detectors. Additionally, as the dark matter parameter space is probed further, careful calibrations of detector response to nuclear recoil interactions must be performed in order to extract useful information (in relation to dark matter particle characterzations) from experimental results. A neutron beam of tunable energy is used in conjunction with a commercial radiation detector to characterize ionization energy losses in germanium during nuclear recoil events. Data indicates agreement with values predicted by the Lindhard equation, providing a best-t k-value of 0.146.

MANTEL-HAENSZEL TYPE ESTIMATORS FOR THE COUNTER-MATCHED SAMPLING DESIGN IN NESTED CASE-CONTROL STUDY

OpenAIRE

Fujii, Yoshinori; Zhang, Zhong-Zhan; 藤井, 良宜

2001-01-01

We are concerned with a counter-matched nested case-control study. Assuming the proportional hazards model, the Mantel-Haenszel estimators of hazard rates are presented in two situations. The proposed estimators can be calculated without estimating the nuisance parameter. Consistent estimators of the variance of the proposed hazard rate estimators are also developed. We compare these estimators to the maximum partial likelihood estimators in the asymptotic variance. The methods are illustrate...

Large Area X-ray Proportional Counter (LAXPC) Instrument on AstroSat and Some Preliminary Results from its performance in the orbit

OpenAIRE

Agrawal, P. C.; Yadav, J. S.; Antia, H. M.; Dedhia, Dhiraj; Shah, P.; Chauhan, Jai Verdhan; Manchanda, R. K.; Chitnis, V. R.; Gujar, V. M.; Katoch, Tilak; Kurhade, V. N.; Madhwani, P.; Manojkumar, T. K.; Nikam, V. A.; Pandya, A. S.

2017-01-01

Large Area X-ray Propositional Counter (LAXPC) instrument on AstroSat is aimed at providing high time resolution X-ray observations in 3 to 80 keV energy band with moderate energy resolution. To achieve large collecting area, a cluster of three co-aligned identical LAXPC detectors, is used to realize an effective area in access of about 6000 cm2 at 15 keV. The large detection volume of the LAXPC detectors, filled with xenon gas at about 2 atmosphere pressure, results in detection efficiency g...

Analytic calculation of radiative-recoil corrections to muonium hyperfine splitting: Electron-line contribution

International Nuclear Information System (INIS)

Eides, M.I.; Karshenboim, S.G.; Shelyuto, V.A.

1991-01-01

The detailed account of analytic calculation of radiative-recoil correction to muonium hyperfine splitting, induced by electron-line radiative insertions, is presented. The consideration is performed in the framework of the effective two-particle formalism. A good deal of attention is paid to the problem of the divergence cancellation and the selection of graphs, relevant to radiative-recoil corrections. The analysis is greatly facilitated by use of the Fried-Yennie gauge for radiative photons. The obtained set of graphs turns out to be gauge-invariant and actual calculations are performed in the Feynman gauge. The main technical tricks, with the help of which we have effectively utilized the existence in the problem of the small parameter-mass ratio and managed to perform all calculations in the analytic form are described. The main intermediate results, as well as the final answer, δE rr = (α(Ζα)/π 2 )(m/M)E F (6ζ(3) + 3π 2 In 2 + π 2 /2 + 17/8), are also presented

Commissioning and performance studies of a proton recoil detector at the COMPASS-II experiment

Energy Technology Data Exchange (ETDEWEB)

Joerg, Philipp; Buechele, Maximilian; Fischer, Horst; Gorzellik, Matthias; Grussenmeyer, Tobias; Herrmann, Florian; Koenigsmann, Kay; Kremser, Paul; Schopferer, Sebastian [Physikalisches Institut, Albert-Ludwigs-Universitaet Freiburg (Germany); Collaboration: COMPASS Collaboration

2014-07-01

The COMPASS-II experiment is a fixed target experiment situated at CERN. A tertiary myon beam from the SPS scattered of protons from a liquid hydrogen target is used to measure Deeply Virtual Compton Scattering (DVCS) and Hard Exclusive Meson Production (HEMP). These processes offer a unique way to determine Generalized Parton Distributions, which are related to the total angular momentum of quarks, antiquarks and gluons in the nucleon by Ji's Sum Rule. One of the major parts of the COMPASS-II upgrade is the CAMERA detector. CAMERA is a proton recoil detector surrounding the COMPASS-II liquid hydrogen target. Its purpose is to measure the recoiled target proton in DVCS and HEMP reactions and viz to act as a veto to ensure the exclusivity of the measurement. The talk gives an outline of the detector and its readout electronics. It is focused on the commissioning and performance of the CAMERA detector and gives a brief insight into the ongoing DVCS analysis.