Study on secondary electron suppression in compact D–D neutron generator
|
摘要
A compact D–D neutron generator, with a peak neutron yield of D–D reactions up to 2.48×10~8 n/s is being developed at Lanzhou University in China for application in real-time neutron activation analysis. During tests, the problem of back acceleration of secondary electrons liberated from the neutron production target by deuterium ions bombardment was encountered. In this study,an electric field method and a magnetic field method for suppressing secondary electrons are designed and experimentally investigated. The experimental results show that the electric field method is superior to the magnetic field method. Effective suppression of the secondary electrons can be achieved via electrostatic suppression when the bias voltage between the target and the extraction-accelerating electrode is >204 V. Furthermore, the secondary electron emission coefficient for the mixed deuterium ion(D_1~+,D_2~+, and D_3~+) impacting on molybdenum is estimated. In the deuterium energy range of 80–120 keV, the estimated secondary electron emission coefficients are approximately 5–5.5 for the mixed deuterium ion glancing incidence of 45° and approximately 3.5–3.9 for the mixed deuterium ion normal incidence.
A compact D–D neutron generator, with a peak neutron yield of D–D reactions up to 2.48×10~8 n/s is being developed at Lanzhou University in China for application in real-time neutron activation analysis. During tests, the problem of back acceleration of secondary electrons liberated from the neutron production target by deuterium ions bombardment was encountered. In this study,an electric field method and a magnetic field method for suppressing secondary electrons are designed and experimentally investigated. The experimental results show that the electric field method is superior to the magnetic field method. Effective suppression of the secondary electrons can be achieved via electrostatic suppression when the bias voltage between the target and the extraction-accelerating electrode is >204 V. Furthermore, the secondary electron emission coefficient for the mixed deuterium ion(D_1~+,D_2~+, and D_3~+) impacting on molybdenum is estimated. In the deuterium energy range of 80–120 keV, the estimated secondary electron emission coefficients are approximately 5–5.5 for the mixed deuterium ion glancing incidence of 45° and approximately 3.5–3.9 for the mixed deuterium ion normal incidence.
A compact D–D neutron generator, with a peak neutron yield of D–D reactions up to 2.48×10~8 n/s is being developed at Lanzhou University in China for application in real-time neutron activation analysis. During tests, the problem of back acceleration of secondary electrons liberated from the neutron production target by deuterium ions bombardment was encountered. In this study,an electric field method and a magnetic field method for suppressing secondary electrons are designed and experimentally investigated. The experimental results show that the electric field method is superior to the magnetic field method. Effective suppression of the secondary electrons can be achieved via electrostatic suppression when the bias voltage between the target and the extraction-accelerating electrode is >204 V. Furthermore, the secondary electron emission coefficient for the mixed deuterium ion(D_1~+,D_2~+, and D_3~+) impacting on molybdenum is estimated. In the deuterium energy range of 80–120 keV, the estimated secondary electron emission coefficients are approximately 5–5.5 for the mixed deuterium ion glancing incidence of 45° and approximately 3.5–3.9 for the mixed deuterium ion normal incidence.
引文
1.H.Z.Bilheux,R.Mcgreevy,I.S.Anderson,Neutron Imaging and Applications(Springer,Boston,2009),p.67
2.International Atomic Energy,Neutron Generators for Analytical Purposes,IAEA Radiation Technology Reports No.1,IAEA,Vienna(2012)
3.J.I.A.Fuquan,G.U.Deshan,C.Daowen et al.,An neutron generator-based NIPGA system for on-site analysis.Nucl.Sci.Tech.21(1),63-64(2010).https://doi.org/10.13538/j.1001-8042/nst.21.63-64
4.R.Ravisankar,P.Eswaran,N.Seshaderssan et al.,Instrumental neutron activation analysis of beachrock samples of South East Coast of Tamilnadu,India.Nucl.Sci.Tech.18(4),204-211(2007).https://doi.org/10.1016/S1001-8042(07)60047-5
5.Z.W.Huang,J.R.Wang,Z.Wei et al.,Development of a compact DD neutron generator.J.Instrum.13(01),P01013(2018).https://doi.org/10.1088/1748-0221/13/01/P01013
6.A.G.Hill,W.W.Buechner,J.S.Clark et al.,The emission of secondary electrons under high energy positive ion bombardment.Phys.Rev.55(5),463(1939).https://doi.org/10.1103/PhysRev.55.463
7.I.H.Tan,M.Ueda,R.S.Dallaqua et al.,Magnetic suppression of secondary electrons in plasma immersion ion implantation.Appl.Phys.Lett.86(2),023509(2005).https://doi.org/10.1063/1.1852704
8.H.C.Bourne Jr.,R.W.Cloud,J.G.Trump,Role of positive ions in high-voltage breakdown in vacuum.J.Appl.Phys.26(5),596-599(1955).https://doi.org/10.1063/1.1722047
9.R.Adams,L.Bort,R.Zboray et al.,Development and characterization of a D-D fast neutron generator for imaging applications.Appl.Radiat.Isot.96,114-121(2015).https://doi.org/10.1016/j.apradiso.2014.11.017
10.M.A.Wasaye,H.Wang,P.He,An algorithm for Monte Carlo simulation of bremsstrahlung emission by electrons.Nucl.Sci.Tech.28(5),65-73(2017).https://doi.org/10.1007/s41365-017-0218-7
11.J.E.Bounden,P.D.Lomer,J.Wood,A neutron tube with constant output(1010n/sec)for activation analysis and reactor applications.Nucl.Instrum.Methods.33(2),283-288(1965).https://doi.org/10.1016/0029-554X(65)90055-8
12.S.G.Forbes,E.R.Graves,R.N.Little,Low voltage 14 MeVneutron source.Rev.Sci.Instrum.24(6),424-427(1953).https://doi.org/10.1063/1.1770737
13.A.S.Tsybin,A.E.Shikanov,Neutron generation in small sealed accelerating tubes.Russ.Phys.J.28(8),609-632(1985).https://doi.org/10.1007/BF00895162
14.I.J.Kim,H.D.Choi,Development of D-D neutron generator.Nucl.Instrum.Meth.B 241(1-4),917-920(2005).https://doi.org/10.1016/j.nimb.2005.07.170
15.C.Waltz,M.Ayllon,T.Becker et al.,Beam-induced backstreaming electron suppression analysis for an accelerator type neutron generator designed for40Ar/39Ar geochronology.Appl.Radiat.Isot.125,124-128(2017).https://doi.org/10.1016/j.apra diso.2017.04.017
16.B.Goplen,L.Ludeking,D.Smith et al.,User-configurable MAGIC for electromagnetic PIC calculations.Comput.Phys.Commun.87(1-2),54-86(1995)
17.H.Nguyen,J.Mankowski,J.C.Dickens et al.,Calculations of secondary electron yield of graphene coated copper for vacuum electronic applications.AIP Adv.8(1),015325(2018).https://doi.org/10.1063/1.5019360
18.J.L.Wurtz,C.M.Tapp,Secondary electron emission from scandium,erbium,scandium deuteride,and erbium deuteride under deuteron bombardment.J.Appl.Phys.43(8),3318-3324(1972).https://doi.org/10.1063/1.1661714
19.J.L.Ke,M.Liu,C.G.Zhou,Deuteron induced secondary electron emission from titanium deuteride surface.Nucl.Instrum.Meth.B280,1-4(2012).https://doi.org/10.1016/j.nimb.2012.02.033
20.M.Liu,J.L.Ke,G.Huang et al.,Measurement of the secondary electrons emission coefficiency from molybdenum induced deuteriums(Nucl.Electron.Detect.Technol.,Beijing,2012).(in Chinese)
21.R.A.Langley,J.Bohdansky,W.Eckstein et al.,Data compendium for plasma-surface interactions.Nucl.Fusion 24(S1),S9(1984).https://doi.org/10.1088/0029-5515/24/S1/001
22.S.B.Svensson,G.Holmen,A.Buren,Angular dependence of the ion-induced secondary-electron yield from solids.Phys.Rev.B24(7),3749(1981).https://doi.org/10.1103/PhysRevB.24.3749
23.G.W.McClure,High-voltage glow discharges in D2gas.I.Diagnostic measurements.Phys.Rev.124(4),969(1961).https://doi.org/10.1103/PhysRev.124.969
24.B.H.Sun,Q.Chen,Characteristics of intense beam for a duoplasmatron source.Nucl.Tech.14(12),731-737(1991).(in Chinese)
2.International Atomic Energy,Neutron Generators for Analytical Purposes,IAEA Radiation Technology Reports No.1,IAEA,Vienna(2012)
3.J.I.A.Fuquan,G.U.Deshan,C.Daowen et al.,An neutron generator-based NIPGA system for on-site analysis.Nucl.Sci.Tech.21(1),63-64(2010).https://doi.org/10.13538/j.1001-8042/nst.21.63-64
4.R.Ravisankar,P.Eswaran,N.Seshaderssan et al.,Instrumental neutron activation analysis of beachrock samples of South East Coast of Tamilnadu,India.Nucl.Sci.Tech.18(4),204-211(2007).https://doi.org/10.1016/S1001-8042(07)60047-5
5.Z.W.Huang,J.R.Wang,Z.Wei et al.,Development of a compact DD neutron generator.J.Instrum.13(01),P01013(2018).https://doi.org/10.1088/1748-0221/13/01/P01013
6.A.G.Hill,W.W.Buechner,J.S.Clark et al.,The emission of secondary electrons under high energy positive ion bombardment.Phys.Rev.55(5),463(1939).https://doi.org/10.1103/PhysRev.55.463
7.I.H.Tan,M.Ueda,R.S.Dallaqua et al.,Magnetic suppression of secondary electrons in plasma immersion ion implantation.Appl.Phys.Lett.86(2),023509(2005).https://doi.org/10.1063/1.1852704
8.H.C.Bourne Jr.,R.W.Cloud,J.G.Trump,Role of positive ions in high-voltage breakdown in vacuum.J.Appl.Phys.26(5),596-599(1955).https://doi.org/10.1063/1.1722047
9.R.Adams,L.Bort,R.Zboray et al.,Development and characterization of a D-D fast neutron generator for imaging applications.Appl.Radiat.Isot.96,114-121(2015).https://doi.org/10.1016/j.apradiso.2014.11.017
10.M.A.Wasaye,H.Wang,P.He,An algorithm for Monte Carlo simulation of bremsstrahlung emission by electrons.Nucl.Sci.Tech.28(5),65-73(2017).https://doi.org/10.1007/s41365-017-0218-7
11.J.E.Bounden,P.D.Lomer,J.Wood,A neutron tube with constant output(1010n/sec)for activation analysis and reactor applications.Nucl.Instrum.Methods.33(2),283-288(1965).https://doi.org/10.1016/0029-554X(65)90055-8
12.S.G.Forbes,E.R.Graves,R.N.Little,Low voltage 14 MeVneutron source.Rev.Sci.Instrum.24(6),424-427(1953).https://doi.org/10.1063/1.1770737
13.A.S.Tsybin,A.E.Shikanov,Neutron generation in small sealed accelerating tubes.Russ.Phys.J.28(8),609-632(1985).https://doi.org/10.1007/BF00895162
14.I.J.Kim,H.D.Choi,Development of D-D neutron generator.Nucl.Instrum.Meth.B 241(1-4),917-920(2005).https://doi.org/10.1016/j.nimb.2005.07.170
15.C.Waltz,M.Ayllon,T.Becker et al.,Beam-induced backstreaming electron suppression analysis for an accelerator type neutron generator designed for40Ar/39Ar geochronology.Appl.Radiat.Isot.125,124-128(2017).https://doi.org/10.1016/j.apra diso.2017.04.017
16.B.Goplen,L.Ludeking,D.Smith et al.,User-configurable MAGIC for electromagnetic PIC calculations.Comput.Phys.Commun.87(1-2),54-86(1995)
17.H.Nguyen,J.Mankowski,J.C.Dickens et al.,Calculations of secondary electron yield of graphene coated copper for vacuum electronic applications.AIP Adv.8(1),015325(2018).https://doi.org/10.1063/1.5019360
18.J.L.Wurtz,C.M.Tapp,Secondary electron emission from scandium,erbium,scandium deuteride,and erbium deuteride under deuteron bombardment.J.Appl.Phys.43(8),3318-3324(1972).https://doi.org/10.1063/1.1661714
19.J.L.Ke,M.Liu,C.G.Zhou,Deuteron induced secondary electron emission from titanium deuteride surface.Nucl.Instrum.Meth.B280,1-4(2012).https://doi.org/10.1016/j.nimb.2012.02.033
20.M.Liu,J.L.Ke,G.Huang et al.,Measurement of the secondary electrons emission coefficiency from molybdenum induced deuteriums(Nucl.Electron.Detect.Technol.,Beijing,2012).(in Chinese)
21.R.A.Langley,J.Bohdansky,W.Eckstein et al.,Data compendium for plasma-surface interactions.Nucl.Fusion 24(S1),S9(1984).https://doi.org/10.1088/0029-5515/24/S1/001
22.S.B.Svensson,G.Holmen,A.Buren,Angular dependence of the ion-induced secondary-electron yield from solids.Phys.Rev.B24(7),3749(1981).https://doi.org/10.1103/PhysRevB.24.3749
23.G.W.McClure,High-voltage glow discharges in D2gas.I.Diagnostic measurements.Phys.Rev.124(4),969(1961).https://doi.org/10.1103/PhysRev.124.969
24.B.H.Sun,Q.Chen,Characteristics of intense beam for a duoplasmatron source.Nucl.Tech.14(12),731-737(1991).(in Chinese)