Pub Date : 1997-07-22DOI: 10.1109/CHERBS.1997.660257
L. Evans, J. Trombka, R. Starr, W. Boynton, S. Bailey
Instrumental backgrounds present a basic limitation to the sensitivity for any gamma-ray detector. This background consists of both discrete lines and a continuum. The discrete background lines are especially important if they occur at the same energies as the lines of interest needed to meet the science objectives of the mission. The continuum background imposes a limit on the signal to noise ratio that can be achieved. Measurements of the gamma-ray continuum background made during the cruise portion of a number of planetary missions are compared. All of these missions used shields to reduce the continuum background. Measurements made during spaceflight can be used to test the effectiveness of different shield designs.
{"title":"Continuum background in space-borne gamma-ray detectors","authors":"L. Evans, J. Trombka, R. Starr, W. Boynton, S. Bailey","doi":"10.1109/CHERBS.1997.660257","DOIUrl":"https://doi.org/10.1109/CHERBS.1997.660257","url":null,"abstract":"Instrumental backgrounds present a basic limitation to the sensitivity for any gamma-ray detector. This background consists of both discrete lines and a continuum. The discrete background lines are especially important if they occur at the same energies as the lines of interest needed to meet the science objectives of the mission. The continuum background imposes a limit on the signal to noise ratio that can be achieved. Measurements of the gamma-ray continuum background made during the cruise portion of a number of planetary missions are compared. All of these missions used shields to reduce the continuum background. Measurements made during spaceflight can be used to test the effectiveness of different shield designs.","PeriodicalId":197895,"journal":{"name":"Conference on the High Energy Radiation Background in Space. Workshop Record","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129411773","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-07-22DOI: 10.1109/CHERBS.1997.660242
W. Boynton, L. Evans, R. Starr, J. Bruckner, S. Bailey, J. Trombka
The Mars Observer Gamma-Ray Spectrometer has provided data on background lines due to natural and cosmic-ray induced radioactivity during the mission's 11-month cruise. These data will help in determining, for future missions, the sensitivity for detection of gamma-ray lines of interest that are at or near the energy of measured background lines.
{"title":"Induced background in the Mars Observer Gamma-Ray Spectrometer","authors":"W. Boynton, L. Evans, R. Starr, J. Bruckner, S. Bailey, J. Trombka","doi":"10.1109/CHERBS.1997.660242","DOIUrl":"https://doi.org/10.1109/CHERBS.1997.660242","url":null,"abstract":"The Mars Observer Gamma-Ray Spectrometer has provided data on background lines due to natural and cosmic-ray induced radioactivity during the mission's 11-month cruise. These data will help in determining, for future missions, the sensitivity for detection of gamma-ray lines of interest that are at or near the energy of measured background lines.","PeriodicalId":197895,"journal":{"name":"Conference on the High Energy Radiation Background in Space. Workshop Record","volume":"136 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122778826","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-07-22DOI: 10.1109/CHERBS.1997.660241
D. Morris, M. McConnell, J. Ryan, R. Diehl, U. Oberlack, V. Schonfelder, M. Varendorff, G. Weidenspointner, H. de Boer, K. Bennett
The COMPTEL gamma-ray telescope has been operating in low Earth orbit for six years, since the launch of the Compton Gamma-Ray Observatory in April 1991. Comparisons of data for different orbits and epochs show evidence of activation on time scales from minutes (/sup 27/Mg, /spl tau//sub 1/2/=9.5 min) to years (/sup 22/Na, /spl tau//sub 1/2/=2.58 yr). The activation is correlated with both the orbital altitude and solar cosmic-ray modulation. Because it requires coincident measurements in two different detectors, COMPTEL is most susceptible to instrumental background events in which two or more photons are produced simultaneously.
{"title":"Activation in the COMPTEL double-scattering gamma-ray telescope","authors":"D. Morris, M. McConnell, J. Ryan, R. Diehl, U. Oberlack, V. Schonfelder, M. Varendorff, G. Weidenspointner, H. de Boer, K. Bennett","doi":"10.1109/CHERBS.1997.660241","DOIUrl":"https://doi.org/10.1109/CHERBS.1997.660241","url":null,"abstract":"The COMPTEL gamma-ray telescope has been operating in low Earth orbit for six years, since the launch of the Compton Gamma-Ray Observatory in April 1991. Comparisons of data for different orbits and epochs show evidence of activation on time scales from minutes (/sup 27/Mg, /spl tau//sub 1/2/=9.5 min) to years (/sup 22/Na, /spl tau//sub 1/2/=2.58 yr). The activation is correlated with both the orbital altitude and solar cosmic-ray modulation. Because it requires coincident measurements in two different detectors, COMPTEL is most susceptible to instrumental background events in which two or more photons are produced simultaneously.","PeriodicalId":197895,"journal":{"name":"Conference on the High Energy Radiation Background in Space. Workshop Record","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121259336","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-07-22DOI: 10.1109/CHERBS.1997.660240
P. Truscott, H. Evans, C. Dyer, M. Cosby, C. Moss
The selection of detector materials for space-borne /spl gamma/-ray systems has previously been based on the response of the scintillator or semiconductor to incident source or background /spl gamma/-rays, and the practicalities associated with the use of these materials in space. Today the availability of a greater variety of detector materials allows potential optimisation for induced radioactive background as well, which contributes an important source of background for instruments in the space environment. Studies have been conducted on induced activation effects in a variety of /spl gamma/-ray detector materials of interest for space applications, including BaF/sub 2/ and GSO. Results are presented from Space Shuttle and proton-beam (300 MeV and 1 GeV) experiments. Detailed radiation transport computer simulations are used to compare and identify the effects observed in the experimental spectra and, for the space experiments, to quantify the contributions to detector activation from the different sources of radiation experienced in the shuttle cabin.
{"title":"Analysis of activation effects in space-borne and proton-beam irradiated /spl gamma/-ray detectors","authors":"P. Truscott, H. Evans, C. Dyer, M. Cosby, C. Moss","doi":"10.1109/CHERBS.1997.660240","DOIUrl":"https://doi.org/10.1109/CHERBS.1997.660240","url":null,"abstract":"The selection of detector materials for space-borne /spl gamma/-ray systems has previously been based on the response of the scintillator or semiconductor to incident source or background /spl gamma/-rays, and the practicalities associated with the use of these materials in space. Today the availability of a greater variety of detector materials allows potential optimisation for induced radioactive background as well, which contributes an important source of background for instruments in the space environment. Studies have been conducted on induced activation effects in a variety of /spl gamma/-ray detector materials of interest for space applications, including BaF/sub 2/ and GSO. Results are presented from Space Shuttle and proton-beam (300 MeV and 1 GeV) experiments. Detailed radiation transport computer simulations are used to compare and identify the effects observed in the experimental spectra and, for the space experiments, to quantify the contributions to detector activation from the different sources of radiation experienced in the shuttle cabin.","PeriodicalId":197895,"journal":{"name":"Conference on the High Energy Radiation Background in Space. Workshop Record","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134484767","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-07-22DOI: 10.1109/CHERBS.1997.660250
F. Lei, A. R. Green, A. Bird, C. Ferguson, A. Dean
A detailed mass model of the ESA INTEGRAL gamma-ray satellite is being built. It is used as geometric input to the comprehensive Monte-Carlo simulation suite GGOD to form the INTEGRAL mass model simulation software. The authors present the current status of the mass model project and preliminary background evaluation results for the two main gamma-ray instruments as well as examples of the use of the simulated background data-sets in the optimization of detector designs.
{"title":"The INTEGRAL mass model and background M-C simulations","authors":"F. Lei, A. R. Green, A. Bird, C. Ferguson, A. Dean","doi":"10.1109/CHERBS.1997.660250","DOIUrl":"https://doi.org/10.1109/CHERBS.1997.660250","url":null,"abstract":"A detailed mass model of the ESA INTEGRAL gamma-ray satellite is being built. It is used as geometric input to the comprehensive Monte-Carlo simulation suite GGOD to form the INTEGRAL mass model simulation software. The authors present the current status of the mass model project and preliminary background evaluation results for the two main gamma-ray instruments as well as examples of the use of the simulated background data-sets in the optimization of detector designs.","PeriodicalId":197895,"journal":{"name":"Conference on the High Energy Radiation Background in Space. Workshop Record","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126265596","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-07-22DOI: 10.1109/CHERBS.1997.660221
R. Starr, L. Evans, S. Floyd, J. Trombka, D. Drake, W. Feldman, S. Squyres, A. C. Rester
A 13-day long-duration balloon flight carrying a high-purity germanium detector with a BGO shield was flown from Williams Field, Antarctica in December 1992. After recovery of the payload the activity induced in the two detectors was measured.
{"title":"Induced radioactivity measured in a germanium detector after a long duration balloon flight","authors":"R. Starr, L. Evans, S. Floyd, J. Trombka, D. Drake, W. Feldman, S. Squyres, A. C. Rester","doi":"10.1109/CHERBS.1997.660221","DOIUrl":"https://doi.org/10.1109/CHERBS.1997.660221","url":null,"abstract":"A 13-day long-duration balloon flight carrying a high-purity germanium detector with a BGO shield was flown from Williams Field, Antarctica in December 1992. After recovery of the payload the activity induced in the two detectors was measured.","PeriodicalId":197895,"journal":{"name":"Conference on the High Energy Radiation Background in Space. Workshop Record","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125451261","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-07-22DOI: 10.1109/CHERBS.1997.660249
B. Graham, B. Phlips, R. Kroeger, J. Kurfess
A Monte Carlo technique for modelling background in space-based gamma-ray telescopes has been developed. The major background components included in this modeling technique are the diffuse cosmic gamma-ray flux, the Earth's atmospheric flux, the decay of nuclei produced by spallation of cosmic rays, trapped protons and their secondaries, the decay of nuclei produced by neutron capture, and the de-excitation of excited states produced by inelastic scattering of neutrons. The method for calculating the nuclear activation and decay component of the background combines the low Earth orbit proton and neutron spectra, the spallation cross sections from Alice91, nuclear decay data from the National Nuclear Data Center's (NNDC) Evaluated Nuclear Structure Data File (ENSDF) database, and three-dimensional gamma-ray and beta transport with Electron Gamma-ray Shower version 4 (EGS4). This Monte Carlo code handles the following decay types: electron capture, /spl beta//sup -/ /spl beta//sup +/, metastable isotopes and short lived intermediate states, and isotopes that have branchings to both /spl beta//sup -/ and /spl beta//sup +/. Actual background from the HEAO 3 space instrument is used to validate the code.
{"title":"Simulation of HEAO 3 background","authors":"B. Graham, B. Phlips, R. Kroeger, J. Kurfess","doi":"10.1109/CHERBS.1997.660249","DOIUrl":"https://doi.org/10.1109/CHERBS.1997.660249","url":null,"abstract":"A Monte Carlo technique for modelling background in space-based gamma-ray telescopes has been developed. The major background components included in this modeling technique are the diffuse cosmic gamma-ray flux, the Earth's atmospheric flux, the decay of nuclei produced by spallation of cosmic rays, trapped protons and their secondaries, the decay of nuclei produced by neutron capture, and the de-excitation of excited states produced by inelastic scattering of neutrons. The method for calculating the nuclear activation and decay component of the background combines the low Earth orbit proton and neutron spectra, the spallation cross sections from Alice91, nuclear decay data from the National Nuclear Data Center's (NNDC) Evaluated Nuclear Structure Data File (ENSDF) database, and three-dimensional gamma-ray and beta transport with Electron Gamma-ray Shower version 4 (EGS4). This Monte Carlo code handles the following decay types: electron capture, /spl beta//sup -/ /spl beta//sup +/, metastable isotopes and short lived intermediate states, and isotopes that have branchings to both /spl beta//sup -/ and /spl beta//sup +/. Actual background from the HEAO 3 space instrument is used to validate the code.","PeriodicalId":197895,"journal":{"name":"Conference on the High Energy Radiation Background in Space. Workshop Record","volume":"77 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131044914","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-07-22DOI: 10.1109/CHERBS.1997.660259
P. Buehler, A. Zehnder, L. Desorgher, W. Hajdas, E. Daly, L. Adams
Simple environment monitors were launched in 1994; one was placed in geostationary transfer orbit (GTO) onboard STRV-1b while the second was installed externally on Mir in LEO. GTO covers the equatorial regime of the inner and outer radiation belts well. Mir encounters the belts near atmospheric cut-off. We summarize these observations. The outer (electron) belt has been subject to many injection events, including during January 1997. Mir data show the strong anisotropy in the low-altitude inner (proton) belt. Results are compared with models.
{"title":"Measurements of the radiation belts from Mir and STRV 1994-1997","authors":"P. Buehler, A. Zehnder, L. Desorgher, W. Hajdas, E. Daly, L. Adams","doi":"10.1109/CHERBS.1997.660259","DOIUrl":"https://doi.org/10.1109/CHERBS.1997.660259","url":null,"abstract":"Simple environment monitors were launched in 1994; one was placed in geostationary transfer orbit (GTO) onboard STRV-1b while the second was installed externally on Mir in LEO. GTO covers the equatorial regime of the inner and outer radiation belts well. Mir encounters the belts near atmospheric cut-off. We summarize these observations. The outer (electron) belt has been subject to many injection events, including during January 1997. Mir data show the strong anisotropy in the low-altitude inner (proton) belt. Results are compared with models.","PeriodicalId":197895,"journal":{"name":"Conference on the High Energy Radiation Background in Space. Workshop Record","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130980263","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-07-22DOI: 10.1109/CHERBS.1997.660260
V. Dmitrenko, A. Galper, V. Gratchev, V. G. Kirillov-Ugryumov, S. Ulin, S. Voronov
The charge ratio, spatial, pitch-angle and energy distributions of the high energy (E/sub e/>10 MeV) electron-positron component of trapped particles in the Earth's radiation belt are presented. The probable mechanisms of particle generation and trapping are considered.
{"title":"New high energy electron component of Earth radiation belt","authors":"V. Dmitrenko, A. Galper, V. Gratchev, V. G. Kirillov-Ugryumov, S. Ulin, S. Voronov","doi":"10.1109/CHERBS.1997.660260","DOIUrl":"https://doi.org/10.1109/CHERBS.1997.660260","url":null,"abstract":"The charge ratio, spatial, pitch-angle and energy distributions of the high energy (E/sub e/>10 MeV) electron-positron component of trapped particles in the Earth's radiation belt are presented. The probable mechanisms of particle generation and trapping are considered.","PeriodicalId":197895,"journal":{"name":"Conference on the High Energy Radiation Background in Space. Workshop Record","volume":"88 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129111115","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-07-22DOI: 10.1109/CHERBS.1997.660248
A. Gerrish
A new Monte-Carlo ray-tracing program useful for the design of active scintillator shielding to reduce radiation background effects in space is described along with results for a BGO anti-Compton shield and a CsI(Na) active collimator.
{"title":"A Monte-Carlo ray-tracing program for modeling scintillators","authors":"A. Gerrish","doi":"10.1109/CHERBS.1997.660248","DOIUrl":"https://doi.org/10.1109/CHERBS.1997.660248","url":null,"abstract":"A new Monte-Carlo ray-tracing program useful for the design of active scintillator shielding to reduce radiation background effects in space is described along with results for a BGO anti-Compton shield and a CsI(Na) active collimator.","PeriodicalId":197895,"journal":{"name":"Conference on the High Energy Radiation Background in Space. Workshop Record","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114817301","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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