Keyword: neutron
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TUPSA36 Measurement of the Dose Rate and the Radiation Spectrum of the Interaction of 2 MeV Proton Beam with a Variety of Structural Materials proton, target, radiation, vacuum 113
 
  • D.A. Kasatov, A.N. Makarov, I.M. Shchudlo, S.Yu. Taskaev
    BINP SB RAS, Novosibirsk, Russia
  
  The paper pre­sents the re­sults of mea­sure­ments of the spec­trum and the ra­di­a­tion dose dur­ing ir­ra­di­a­tion of dif­fer­ent con­struc­tion ma­te­ri­als with 2 MeV pro­ton beam. There are shown the spec­tra of the in­duced ac­tiv­ity of a num­ber of ma­te­ri­als and sig­nals from the neu­tron de­tec­tor. Based on the ob­tained re­sults it is made the op­ti­mal choice of the tar­get ma­te­r­ial, on which it is de­posited a thin layer of lithium to gen­er­ate ep­ither­mal neu­trons used for boron neu­tron cap­ture ther­apy of ma­lig­nant tu­mors. Rec­om­men­da­tions are given for ma­te­ri­als de­sir­able to use in­side the high-en­ergy beam trans­port­ing chan­nel to re­duce the dose of con­comi­tant ra­di­a­tion.  
 
TUPSA38 Estimation of the Efficiency of Biological Shielding for the Circular Hall of U-70 Accelerator at IHEP shielding, detector, photon, target 118
 
  • O.V. Sumaneev, G.I. Britvich, M.Y. Kostin, V.A. Pikalov
    IHEP, Moscow Region, Russia
  
  Re­port pre­sents es­ti­ma­tion of bi­o­log­i­cal shield­ing ef­fi­ciency for an­nu­lar hall of U-70 ac­cel­er­a­tor. Dis­tri­b­u­tion of neu­tron flux in con­crete shield­ing of pro­ton ac­cel­er­a­tor mea­sure­ments car­ried out by method of long-lived iso­topes spe­cific ac­tiv­ity de­ter­mi­na­tion. The ex­per­i­men­tal data may be com­pared with Monte-Carlo sim­u­la­tion.  
 
WEPSB11 Test Results of 433 MHz Deuteron Linac (RFQ) rfq, target, detector, ion 177
 
  • Y.A. Svistunov, S.V. Grigorenko, A.N. Kuzhlev, A.K. Liverovskij, I.I. Mezhov, A.A. Ryaskov, A.P. Strokach, V.F. Tsvetkov, O.L. Veresov, Yu. Zuev
    NIIEFA, St. Petersburg, Russia
  
  The re­sults of bench tests of the high fre­quency deuteron ac­cel­er­a­tor (RFQ) with out­put en­ergy of 1 MeV and op­er­at­ing fre­quency of 433 MHz are pre­sented. There are briefly dis­cussed RFQ con­struc­tion and as­sem­bling, rf sys­tem, is­sues of tun­ing and mea­sur­ing of elec­tro­dy­nam­i­cal char­ac­ter­is­tics of RFQ. Out­put data ob­tained under ac­cel­er­ated beam op­er­a­tion with foil mon­i­tor and Beryl­lium tar­get are given.  
 
WEPSB16 Studying of the Accompanying Charged Particles in the Tandem Accelerator with Vacuum Insulation detector, vacuum, proton, target 189
 
  • A.N. Makarov, D.A. Kasatov, I.M. Shchudlo, S.Yu. Taskaev
    BINP SB RAS, Novosibirsk, Russia
  
  On the tan­dem ac­cel­er­a­tor with vac­uum in­su­la­tion in a steady long mode it was ob­tained 1.6 mA cur­rent of pro­tons with 2 MeV en­ergy. It was stud­ied the one of the pos­si­ble rea­sons of cur­rent lim­i­ta­tion – the ap­pear­ance of ac­com­pa­ny­ing charged par­ti­cles dur­ing ac­cel­er­a­tion of the ion beam. The paper pre­sents and dis­cusses the re­sults of the ac­com­pa­ny­ing beam mea­sure­ment using a spe­cial de­tec­tor. The de­tec­tor reg­is­tered an op­po­site pos­i­tive cur­rent in the range of 80-170 mkA, which is di­rectly de­pen­dent on vac­uum con­di­tions in the ac­cel­er­a­tor. Also it was mea­sured the de­pen­dence of the dose rate on the total cur­rent in the ac­cel­er­at­ing gap. These mea­sure­ments con­firmed that in­jected H− beam ion­izes resid­ual and strip­ping gas mainly in the area be­fore the first elec­trode and two pro­pos­als were made to min­i­mize the ac­com­pa­ny­ing cur­rent.  
 
WEPSB17 Development of the Injector for Vacuum Insulated Tandem Accelerator ion, vacuum, ion-source, acceleration 191
 
  • A.S. Kuznetsov, A.A. Alexander, M.A. Tiunov
    BINP SB RAS, Novosibirsk, Russia
  • D.A. Kasatov, A.M. Koshkarev
    NSU, Novosibirsk, Russia
  
  The Vac­uum In­su­lated Tan­dem Ac­cel­er­a­tor is built at the Bud­ker In­sti­tute of Nu­clear Physics.* The ac­cel­er­a­tor is de­signed for de­vel­op­ment of the con­cept of ac­cel­er­a­tor-based boron neu­tron cap­ture ther­apy of ma­lig­nant tu­mors in the clinic.** In the ac­cel­er­a­tor the neg­a­tive hy­dro­gen ions are ac­cel­er­ated by the high volt­age elec­trode po­ten­tial to the half of re­quired en­ergy, and after con­ver­sion of the ions into pro­tons by means of a gas strip­ping tar­get the pro­tons are ac­cel­er­ated again by the same po­ten­tial to the full beam en­ergy. A num­ber of in­no­v­a­tive ideas posited in the de­sign make it pos­si­ble to ac­cel­er­ate in­tense beams in a com­pact ac­cel­er­a­tor. Num­ber of in­ves­ti­ga­tions re­vealed weak points of the ac­cel­er­a­tor in­jec­tor: un­nec­es­sary beam strip­ping by the resid­ual gas and com­plex­ity to im­prove the vac­uum con­di­tions, the in­flu­ence of the strip­ping gas to the ion source op­er­a­tion sta­bil­ity. To en­sure the beam pa­ra­me­ters and re­li­a­bil­ity of the fa­cil­ity op­er­a­tion re­quired for clin­i­cal ap­pli­ca­tions, the new in­jec­tor is de­signed based on the ion source with a cur­rent up to 15 mA, pro­vid­ing the pos­si­bil­ity of pre­lim­i­nary beam ac­cel­er­a­tion upto 120-200 keV. The paper pre­sents the de­sign of the in­jec­tor and the re­sults of cal­cu­la­tions per­formed.
*Aleynik V., Bashkirtsev A., et al. Applied Radiation and Isotopes 88 (2014) 177-179.
**Bayanov B., Belov V., et al. Nuclear Instr. and Methods in Physics Research A 413/2-3 (1998) 397-426. 		 
 
WEPSB20 Experimental Study of the Time Dependence of the Activity of Delayed Neutrons in the Fission of 235U by Neutrons from the Reaction 7Li(p, n) on the Electrostatic Accelerator EG-1 experiment, detector, proton, target 200
 
  • K.V. Mitrofanov, A.S. Egorov, D.E. Gremyachkin, V.F. Mitrofanov, V.M. Piksaikin, B.F. Samylin
    IPPE, Obninsk, Russia
  
  In the pre­sent work the in­stal­la­tion cre­ated on the basis of the ac­cel­er­a­tor EG-1 (IPPE) for the ex­per­i­men­tal stud­ies of the time de­pen­dence of de­layed neu­tron ac­tiv­ity from neu­tron in­duced fis­sion of 235U is de­scribed. Mea­sure­ments were car­ried out with neu­tron beam gen­er­ated with the help of the 7Li(p, n) re­ac­tion. The lower limit of the in­ves­ti­gated time range was gov­erned by the pro­ton beam switch­ing sys­tem that was 20 ms. It was shown that the tem­po­rary char­ac­ter­is­tics of de­layed neu­trons from the fis­sion of 235U by ep­ither­mal neu­trons is con­sis­tent with the time de­pen­dence which at pre­sent is rec­om­mended as a stan­dard. In case of the fast neu­tron in­duced fis­sion of 235U the mea­sured decay curve of de­layed neu­trons shows ex­cess of count­ing rate in the time in­ter­val 0.01-0.2 s as com­pared with the decay curve cor­re­spond­ing to the rec­om­mended data.  
 
WEPSB21 Registration of Gamma Rays from the Reaction 16O(n, p)16N on the Direct Neutron Beam of Cascade Generator KG-2.5 target, background, detector, experiment 203
 
  • K.V. Mitrofanov, A.S. Egorov, V.M. Piksaikin, B.F. Samylin
    IPPE, Obninsk, Russia
  
  In the pre­sent work the re­sults of analy­sis of the oxy­gen con­tent in the water with the help of gamma-rays reg­is­tra­tion from the re­ac­tion 16O(n, p)16N is de­scribed. The sam­ples were in­stalled per­ma­nently on the di­rect beam of neu­trons gen­er­ated by the re­ac­tion 7Li(d, n) in the cas­cade gen­er­a­tor KG-2.5 (IPPE). A com­par­i­son was car­ried out with ex­per­i­men­tal data ob­tained by the ac­ti­va­tion method in sim­i­lar ex­per­i­men­tal con­di­tions.  
 
WEPSB23 Set-up for Measurements of Delayed Neutron Characteristics in Interaction of Heavy Nuclei with Relativistic Protons of the Synchrocyclotron PINP Gatchina proton, detector, synchro-cyclotron, experiment 209
 
  • A.S. Egorov, V.F. Mitrofanov, V.M. Piksaikin, B.F. Samylin
    IPPE, Obninsk, Russia
  
  In the pre­sent paper the method and set-up for mea­sure­ments of de­layed neu­tron char­ac­ter­is­tics in in­ter­ac­tion of heavy nu­clei with rel­a­tivis­tic pro­tons are de­scribed. On the basis of this method the time de­pen­dence of de­layed neu­tron ac­tiv­ity has been mea­sured from in­ter­ac­tion of 238U sam­ple with 1 GeV pulsed pro­ton beam of the syn­chro­cy­clotron of the Pe­ters­burg In­sti­tute of Nu­clear Physics, Gatchina. The mea­sured data was an­a­lyzed in frame of 8-group pre­cur­sor's model with a uni­fied set of half-lives. Ob­tained re­sults on the frac­tional yields of de­layed neu­trons are com­pared with the ap­pro­pri­ate data from the fast neu­tron in­duced fis­sion of 238U.  
 
WEPSB44 Neutron Radiation Monitoring of the Therapeutic Proton Beam Transportation radiation, proton, monitoring, beam-transport 262
 
  • V.M. Skorkin
    RAS/INR, Moscow, Russia
  
  A mon­i­tor­ing sys­tem on­line con­trols a ther­a­peu­tic pro­ton beam by mea­sur­ing a sec­ondary neu­tron ra­di­a­tion from the beam losses. The sys­tem con­sists of neu­tron de­tec­tors in the trans­port path pas­sage from Linac to the fa­cil­ity of pro­ton ther­apy and ter­mi­nal con­troller con­nected to the com­puter. The neu­tron de­tec­tors mea­sure a level of the sec­ondary neu­tron ra­di­a­tion in real time along of the trans­port chan­nel, near the for­ma­tive el­e­ments. The sys­tem of the neu­tron de­tec­tors reg­is­ters tem­po­ral vari­a­tions of the beam in­ten­sity in local areas trans­port med­ical chan­nel. These changes arise are due to changes in op­er­at­ing mode of the chan­nels or in­sta­bil­ity of the el­e­ments form­ing the beam. The mon­i­tor­ing sys­tem al­lows to de­ter­mine a in­ten­sity and tem­po­ral struc­ture of the ther­a­peu­tic beam and to de­tect mode and in­sta­bil­ity of the for­ma­tive el­e­ments.  
 
WEPSB49 Method of Measuring Fast Neutron Fluence Using the Planar Silicon Detectors detector, radiation, experiment, lattice 272
 
  • A.I. Shafronovskaia
    JINR, Dubna, Moscow Region, Russia
  
  Funding: Joint Institute for Nuclear Research, Dubna
The tech­nique re­ported of fast neu­tron flu­ence mea­sure­ments using sil­i­con de­tec­tors. One of the main macro­scopic ef­fects at ra­di­a­tion dam­age of sil­i­con de­tec­tors by fast neu­trons is in­crease of the re­verse cur­rent. The in­cre­ment of the re­verse cur­rent de­tec­tor is a lin­ear de­pen­dence on fast neu­tron flu­ence and is de­ter­mined by the for­mula: DI=aIxFxV, where: DI=(I1-I0), (А) – the mea­sured in­cre­ment of the re­verse dark cur­rent after ir­ra­di­a­tion of the de­tec­tor nor­mal­ized to tem­per­a­ture of +20 C, aI=(5±0.5)'10-17, (А/сm) – cur­rent con­stant ra­di­a­tion dam­age of sil­i­con for neu­trons with en­ergy 1 MeV, F, (сm-2) - equiv­a­lent flu­ence of fast neu­trons with en­ergy 1 MeV, V=d'S, (сm3) – the vol­ume of the de­tec­tor at the full de­ple­tion volt­age. The ex­per­i­men­tal re­sults of mea­sure­ments of fast neu­tron flu­ence with sil­i­con de­tec­tors are ob­tained on the pulsed fast neu­trons re­ac­tor (IBR-2, chan­nel #3) and on the ex­per­i­men­tal fa­cil­ity KV­INTA JINR, Dubna. 		 
 
THPSC50 Neutron Accelerating Tubes with Microwave Deuterons Source Using Electron-cyclotron Resonance Effect ion, plasma, cavity, ECR 441
 
  • A.N. Didenko, B.Y. Bogdanovich, K.I. Kozlovskiy, A. Nesterovich, A.V. Prokopenko, V.L. Shatokhin, A.E. Shikanov
    MEPhI, Moscow, Russia
  
  The phys­i­cal prin­ci­ples of in­creased ef­fi­ciency neu­tron ac­cel­er­at­ing tubes based on the mi­crowave sources of heavy hy­dro­gen nu­clides, using the elec­tron-cy­clotron res­o­nance ef­fect (ECR) are con­sid­ered. The au­thors' the­o­ret­i­cal re­sults are given on elec­tro­mag­netic os­cil­la­tions gen­er­a­tion in the work­ing vol­ume of the ion source of the ac­cel­er­at­ing tube with the bound­ary ex­ci­ta­tion of a mi­crowave dis­charge. Res­onator and wave­guide modes for ECR-plasma ex­ci­ta­tion are thus ex­am­ined. Fea­tures of neu­tron gen­er­a­tion in these ac­cel­er­a­tor neu­tron tubes based on mi­crowave source of heavy hy­dro­gen nu­clides are an­a­lyzed. The al­go­rithm is de­vel­oped and nu­mer­i­cal sim­u­la­tion of neu­tron pulse for­ma­tion in neu­tron gen­er­a­tors based on mi­crowave source is done tak­ing into ac­count tar­get shape and the pos­si­ble deuterons res­o­nant recharge. Fre­quency de­pen­dences of the en­ergy flux den­sity trans­mit­ted from an al­ter­nat­ing elec­tro­mag­netic field to the elec­tron com­po­nent of the plasma are ob­tained de­pend­ing on the con­stant lon­gi­tu­di­nal mag­netic field in­duc­tion and pres­sure in the dis­charge cham­ber. The re­sults of these stud­ies could form the basis for the ef­fi­cient do­mes­tic portable neu­tron gen­er­a­tors de­vel­op­ment based on ac­cel­er­at­ing tubes with mi­crowave hy­dro­gen nu­clides sources.  
 
THPSC51 Ion Source Deuteron Beam Acceleration in Gas-filled Ion-optic System target, ion, electron, space-charge 444
 
  • V.I. Rashchikov
    MEPhI, Moscow, Russia
  
  Deuteron beam ac­cel­er­a­tion in ion-op­tic sys­tem of gas-filled neu­tron tubes was in­ves­ti­gated. PIC code SUMA* used for com­puter sim­u­la­tion of ion­iza­tion and knock on processes and there in­flu­ence on deuteron beam pa­ra­me­ters. When deuteron and ion­ized par­ti­cles space charge self-field forces be­come the same order of mag­ni­tude as ex­ter­nal one, vir­tual cath­ode may oc­curs. It is hap­pens be­cause of in­jected from ion source deuterons can­not over­come their own space charge po­ten­tial wall and move in trans­verse di­rec­tion. How­ever, elec­trons, pro­duced by ion­iza­tion, are trapped within the deuteron beam space charge po­ten­tial wall and de­crease it sig­nif­i­cantly. Thus, space charge neu­tral­iza­tion of deuteron beams by elec­trons, may con­sid­er­ably in­crease tar­get cur­rent and, as a re­sult, out­put neu­tron flow. More­over, own lon­gi­tu­di­nal elec­tric field rise near the tar­get leads to re­duc­tion of ac­cel­er­at­ing elec­trode – tar­get po­ten­tial wall, which was made to pre­vent knock on emis­sion from the tar­get. As a re­sult, ad­di­tional knocked on elec­trons may ap­pear in the re­gion and should be taken into ac­count. The data ob­tained were com­pared with ex­per­i­men­tal re­sults.
* A.N. Didenko, V.I. Rashchikov, V.E. Fortov, Technical Physics, Vol. 56, No. 10,pp. 1535–1538, 2011 		 
 
THPSC52 Dynamics of Plasma-Beam Formations in the Acceleration Gap of the Pulse Neutron Generator-based Vacuum Neutron Tube plasma, target, ion, vacuum 447
 
  • S. Sergey, S. Maslennikov, E. Shkolnikov
    National Research Nuclear University (MEPhI), Moscow, Russia
  • A. Agafonov
    LPI RAS, Moscow, Russia
  
  The analy­sis of dy­nam­ics of plasma flows con­tain­ing deu­terium, zir­co­nium ions, and elec­trons in ac­cel­er­a­tion gap of the pulsed neu­tron gen­er­a­tor vac­uum neu­tron tube* is pre­sented in the paper. The in­ves­ti­ga­tions have been un­der­taken with the use of code KARAT** for the two-di­men­sional time-de­pen­dant regime. The lim­it­ing cur­rents of each com­po­nent for the real geom­e­try of ac­cel­er­a­tion gap have been de­ter­mined. The dif­fer­ences be­tween the val­ues of these cur­rents and those de­ter­mined with the use of the Child-Lang­muir equa­tion have been demon­strated. The analy­sis of dy­nam­ics of plasma emit­ter in the gap has been per­formed by the ex­am­ple of ac­cel­er­at­ing volt­age of 120 kV and pulse du­ra­tion of 1.2 mks. It has been shown that the value of the cur­rent in­com­ing in the gap from the ions source can dif­fer strongly from the cur­rent value at the tar­get. For in­creas­ing of this value the par­ti­tion­ing of ac­cel­er­a­tion gap with the use of con­duc­tive grid which is trans­par­ent for beam and has sev­eral geo­met­ric con­fig­u­ra­tions has been pro­posed. The ring con­fig­u­ra­tion of the emit­ter has been con­sid­ered for the same pur­poses. The cal­cu­la­tions have shown that the com­bi­na­tion of these two meth­ods de­scribed above can allow trans­port­ing deuterons cur­rent from the anode grid to the tar­get with­out losses.
* E.P.Bogolubov, V.I.Ryzhkov, D.I.Yurkov. Conference "PNG and Technologies on Their Basis",2013,p.14.
** V.P.Tarakanov. User's Manual for Code KARAT. Berkeley Research Associates, Inc. 1992, p.127.
 		 
 
THPSC53 The NG-10 Neutron Generator for Production of Neutron Fluxes in Continuous and Pulse Modes controls, ion, target, power-supply 450
 
  • D.A. Solnyshkov, A.V. Antonov, A.N. Kuzhlev, N.P. Mikulinas, A.V. Morozov, G.G. Voronin
    NIIEFA, St. Petersburg, Russia
  
  De­signed neu­tron gen­er­a­tor is de­signed for a neu­tron yield 1x1011 neu­trons / s in con­tin­u­ous mode and in­cludes ion ac­cel­er­a­tor with an ac­cel­er­at­ing volt­age, con­tin­u­ously ad­justable in the range of 120-150 keV and a beam cur­rent of atomic deu­terium ions up to 2 mA, and the tar­get de­vice, in which used Ti-T tar­get dif­fer­ent di­am­e­ters. In ad­di­tion to high and sta­ble yield of neu­trons in time when op­er­at­ing con­tin­u­ously gen­er­a­tor pro­vides pulsed mode of op­er­a­tion over a wide range of du­ra­tion and pulse rep­e­ti­tion rate. Pulsed neu­tron gen­er­a­tor op­er­a­tion is per­formed by mod­u­lat­ing the dis­charge cur­rent of the ion source. For this pur­pose, a unique sys­tem of power dis­charge, which al­lows for both con­tin­u­ous and pulse modes. In this case it is pos­si­ble to pro­duce a smooth ad­just­ment of the pulse width of the beam cur­rent. Switch from pulse mode to DC promptly made with the re­mote con­trol.  
 
FRCB01 Problems and Prospects of the Tandem Accelerator with Vacuum Insulation vacuum, high-voltage, ion, tandem-accelerator 465
 
  • S.Yu. Taskaev, D.A. Kasatov, A.S. Kuznetsov, A.N. Makarov, I.M. Shchudlo, I.N. Sorokin
    BINP SB RAS, Novosibirsk, Russia
  
  Funding: Ministry of Education and Science of Russia (project RFMEFI57614X0181)
At BINP for de­vel­op­ment of boron neu­tron cap­ture ther­apy it is pro­posed and con­structed the tan­dem ac­cel­er­a­tor with vac­uum in­su­la­tion, which is char­ac­ter­ized by rapid ac­cel­er­a­tion of charged par­ti­cles. Prob­lems of high-volt­age strength gaps due to the large stored en­ergy and strong elec­tro­sta­tic lens are solved. It is ob­tained a sta­tion­ary 1.6 mA 2 MeV pro­ton beam hav­ing 0.1% en­ergy mono­chro­matic­ity and 0.5% cur­rent sta­bil­ity. It is clar­i­fied, that fur­ther in­crease of the pro­ton cur­rent in the sta­ble mode with­out break­downs is lim­ited by the ac­com­pa­ny­ing cur­rent in the high-volt­age gaps. It is pro­posed to make vac­uum con­di­tions bet­ter in the input of the ac­cel­er­a­tor using ad­di­tional cry­op­ump, to mod­ern­ize argon strip­ping tar­get by its tilt­ing or shift­ing and to use dif­fer­en­tial pump­ing in­side the high-volt­age elec­trode. Ob­tain­ing of the 3 mA 2.5 MeV pro­ton beam will allow us to con­duct boron neu­tron cap­ture ther­apy. 		 
slides icon Slides FRCB01 [0.815 MB]  
 
FRCB02 Dynamics of Processes in Subcritical Reactor Driven by Linear Accelerator controls, feedback, linac, proton 467
 
  • A.G. Golovkina, I.V. Kudinovich, D.A. Ovsyannikov
    St. Petersburg State University, St. Petersburg, Russia
  • Y.A. Svistunov
    Saint Petersburg State University, Saint Petersburg, Russia
  
  Funding: St. Petersburg State University, grant No. 9.38.673.2013
In this paper dy­nam­ics of processes in ac­cel­er­a­tor dri­ven sys­tem (ADS) is con­sid­ered. ADS re­ac­tor op­er­ates at sub­crit­i­cal level and the nec­es­sary neu­tron sup­ply comes from the in­ter­ac­tion of a charged par­ti­cles beam with a heavy atom nu­cleus (spal­la­tion re­ac­tion). Math­e­mat­i­cal model of dy­nam­ics of sub­crit­i­cal re­ac­tor con­trolled by lin­ear ac­cel­er­a­tor is pre­sented. Cal­cu­la­tion re­sults of tran­sient processes in the re­ac­tor core tak­ing into ac­count fuel feed­back. The re­ac­tor power level con­trol is car­ried out through the reg­u­la­tion of linac cur­rent im­pulses fre­quency.