304L 6.35 * 1mm Stainless hlau coiled tubing lwm tus neeg, Ua qauv qhia ntawm lub siab tawv lithium beam rau tsim pulsed ncaj neutrons

Ua tsaug rau koj tuaj xyuas Nature.com.Koj siv lub browser version nrog kev txhawb nqa CSS tsawg.Rau qhov kev paub zoo tshaj plaws, peb xav kom koj siv qhov browser tshiab (lossis lov tes taw Compatibility Hom hauv Internet Explorer).Tsis tas li ntawd, txhawm rau xyuas kom muaj kev txhawb nqa tsis tu ncua, peb qhia lub vev xaib tsis muaj qauv thiab JavaScript.
Sliders qhia peb kab lus rau ib tus swb.Siv cov nyees khawm rov qab thiab tom ntej kom txav mus los ntawm cov slides, lossis cov khawm tswj swb thaum kawg kom txav mus los ntawm txhua tus swb.

Raws li lwm txoj hauv kev rau kev kawm txog cov tshuab hluav taws xob nuclear, lub tshuab hluav taws xob ua kom nrawm nrawm-tsav neutron generator siv lub lithium-ion beam tsav tsheb yuav yog tus neeg sib tw pheej hmoo vim tias nws tsim hluav taws xob tsis xav tau me ntsis.Txawm li cas los xij, nws nyuaj rau kev xa cov kab mob hnyav ntawm lithium ions, thiab kev siv tswv yim ntawm cov khoom siv no suav tias yog tsis yooj yim sua.Qhov teeb meem mob hnyav tshaj plaws ntawm cov dej tsis txaus ion tau daws los ntawm kev siv cov txheej txheem plasma implantation ncaj qha.Nyob rau hauv cov tswv yim no, ib tug high-density pulsed plasma generated los ntawm laser ablation ntawm ib tug lithium hlau ntawv yog zoo txhaj thiab ceev los ntawm ib tug high-frequency quadrupole accelerator (RFQ accelerator).Peb tau ua tiav lub siab tshaj plaws beam tam sim no ntawm 35 mA nrawm mus rau 1.43 MeV, uas yog ob qhov kev txiav txim siab ntau dua li cov twj tso kua mis thiab cov tshuab accelerator tuaj yeem muab tau.
Tsis zoo li X-rays lossis cov khoom them nqi, neutrons muaj qhov tob tob tob thiab sib cuam tshuam nrog cov teeb meem condensed, ua rau lawv muaj ntau yam kev soj ntsuam rau kev kawm cov khoom ntawm cov khoom 1,2,3,4,5,6,7.Tshwj xeeb, cov txheej txheem neutron scattering feem ntau yog siv los kawm txog qhov muaj pes tsawg leeg, cov qauv, thiab cov kev ntxhov siab sab hauv hauv cov teeb meem condensed thiab tuaj yeem muab cov ncauj lus kom ntxaws txog cov kab sib txuas hauv cov hlau alloy uas nyuaj rau kev kuaj xyuas siv X-ray spectroscopy8.Txoj kev no suav hais tias yog ib qho cuab yeej muaj zog hauv kev tshawb fawb yooj yim thiab siv los ntawm cov tuam txhab hlau thiab lwm yam ntaub ntawv.Tsis ntev los no, neutron diffraction tau siv los txheeb xyuas cov kev ntxhov siab nyob hauv cov khoom siv tshuab xws li tsheb ciav hlau thiab dav hlau qhov chaw 9,10,11,12.Neutrons kuj tseem siv tau rau hauv cov roj thiab roj qhov dej vim tias lawv tau yooj yim ntes los ntawm cov ntaub ntawv nplua nuj proton13.Cov txheej txheem zoo sib xws kuj tau siv hauv kev tsim vaj tsev engineering.Kev ntsuam xyuas tsis muaj kev puas tsuaj rau neutron yog ib qho cuab yeej zoo rau kev tshawb nrhiav qhov yuam kev hauv cov tsev, qhov thiab txuas hniav.Kev siv cov kab hluav taws xob neutron tau nquag siv hauv kev tshawb fawb thiab kev lag luam, ntau yam uas tau tsim keeb kwm siv nuclear reactors.
Txawm li cas los xij, nrog kev pom zoo thoob ntiaj teb ntawm kev tsis muaj kev loj hlob nuclear, tsim cov reactors me me rau kev tshawb fawb lub hom phiaj yog qhov nyuaj zuj zus.Tsis tas li ntawd, kev sib tsoo Fukushima tsis ntev los no tau ua rau lub tsev nuclear reactors yuav luag txhua tus neeg.Nyob rau hauv kev twb kev txuas nrog cov qauv no, qhov kev thov rau neutron qhov chaw ntawm accelerators yog loj hlob2.Raws li lwm txoj hauv kev rau cov tshuab hluav taws xob nuclear, ntau qhov chaw ua haujlwm loj-splitting neutron twb tau ua haujlwm14,15.Txawm li cas los xij, kom siv tau zoo dua ntawm cov khoom ntawm cov kab hluav taws xob neutron, nws yog ib qho tsim nyog yuav tsum nthuav dav kev siv cov khoom siv compact ntawm cov accelerators, 16 uas tej zaum yuav muaj nyob rau hauv kev lag luam thiab cov tsev kawm ntawv tshawb fawb.Accelerator neutron cov peev txheej tau ntxiv cov peev txheej tshiab thiab ua haujlwm ntxiv rau kev ua haujlwm hloov pauv rau nuclear reactors14.Piv txwv li, lub tshuab hluav taws xob linac-tsav tau yooj yim tsim cov kwj ntawm neutrons los ntawm kev tswj cov kab teeb tsav.Thaum tso tawm, neutrons nyuaj rau kev tswj thiab kev ntsuas hluav taws xob nyuaj rau kev txheeb xyuas vim lub suab nrov tsim los ntawm cov neutrons tom qab.Pulsed neutrons tswj los ntawm lub accelerator zam qhov teeb meem no.Ob peb txoj haujlwm raws li proton accelerator thev naus laus zis tau thov thoob ntiaj teb17,18,19.Cov tshuaj tiv thaiv 7Li(p, n)7Be thiab 9Be(p, n)9B feem ntau yog siv nyob rau hauv proton-driven compact neutron generators vim lawv yog endothermic tshua20.Tshaj hluav taws xob thiab cov khoom siv hluav taws xob ntau tuaj yeem txo qis yog tias lub zog xaiv los ua kom lub zog ntawm cov kab hluav taws xob proton yog me ntsis siab dua tus nqi pib.Txawm li cas los xij, qhov loj ntawm lub hom phiaj nucleus loj dua li ntawm cov protons, thiab cov txiaj ntsig neutrons tawg mus rau txhua qhov kev qhia.Xws li ze rau isotropic emission ntawm neutron flux tiv thaiv kev thauj mus los ntawm neutrons mus rau qhov khoom ntawm kev kawm.Tsis tas li ntawd, txhawm rau kom tau txais cov koob tshuaj ntawm cov neutrons ntawm qhov chaw ntawm cov khoom, nws yog ib qho tsim nyog yuav tsum tau nce ntau ntawm cov protons txav thiab lawv lub zog.Yog li ntawd, cov koob tshuaj loj ntawm gamma rays thiab neutrons yuav nthuav tawm los ntawm cov ces kaum loj, rhuav tshem qhov zoo ntawm cov tshuaj tiv thaiv endothermic.Ib tug raug accelerator-driven compact proton-raws li neutron generator muaj zog hluav taws xob shielding thiab yog bulkiest ib feem ntawm lub system.Qhov yuav tsum tau ua kom lub zog ntawm kev tsav tsheb protons feem ntau yuav tsum muaj kev nce ntxiv hauv qhov loj ntawm qhov chaw accelerator.
Txhawm rau kov yeej qhov tsis txaus ntseeg ntawm cov khoom siv sib xyaw ua ke ntawm cov neutron ntawm cov accelerators, ib qho kev tawm tswv yim inversion-kinematic cov tshuaj tiv thaiv tau npaj siab 21.Nyob rau hauv cov tswv yim no, ib tug hnyav lithium-ion beam yog siv raws li ib tug taw qhia beam es tsis txhob ntawm ib tug proton beam, tsom rau hydrogen-nplua nuj cov ntaub ntawv xws li hydrocarbon plastics, hydrides, hydrogen gas, los yog hydrogen plasma.Lwm txoj hauv kev tau txiav txim siab, xws li beryllium ion-driven beams, txawm li cas los xij, beryllium yog ib qho tshuaj lom uas yuav tsum tau saib xyuas tshwj xeeb hauv kev tuav.Yog li ntawd, lub lithium beam yog qhov haum tshaj plaws rau inversion-kinematic cov tshuaj tiv thaiv schemes.Txij li thaum lub zog ntawm lithium nuclei ntau dua li ntawm cov protons, qhov nruab nrab ntawm qhov loj ntawm kev sib tsoo nuclear txuas ntxiv mus rau pem hauv ntej, thiab cov neutrons kuj tau tawm mus tom ntej.Qhov no feature zoo heev tshem tawm pliaj gamma rays thiab siab lub kaum sab xis neutron emissions22.Ib qho kev sib piv ntawm cov xwm txheej ib txwm muaj ntawm lub cav proton thiab qhov cuam tshuam rov qab kinematics yog qhia hauv daim duab 1.
Piv txwv ntawm cov kaum neutron ntau lawm rau proton thiab lithium beams (kos nrog Adobe Illustrator CS5, 15.1.0, https://www.adobe.com/products/illustrator.html).(a) Neutrons tuaj yeem raug tshem tawm hauv txhua qhov kev taw qhia raws li qhov tshwm sim ntawm cov tshuaj tiv thaiv vim qhov tseeb tias txav protons ntaus cov atoms hnyav dua ntawm lub hom phiaj lithium.(b) Hloov pauv, yog tias tus tsav tsheb lithium-ion foob pob lub hom phiaj hydrogen-nplua nuj, cov neutrons tau tsim nyob rau hauv lub khob nqaim nyob rau hauv kev coj mus rau pem hauv ntej vim qhov siab tshaj plaws ntawm qhov system qhov nruab nrab ntawm qhov loj.
Txawm li cas los xij, tsuas yog ob peb lub inverse kinematic neutron generators muaj nyob vim qhov nyuaj ntawm kev tsim cov flux ntawm hnyav ions nrog tus nqi siab piv rau protons.Tag nrho cov nroj tsuag no siv qhov tsis zoo sputter ion qhov chaw ua ke nrog tandem electrostatic accelerators.Lwm hom ion qhov chaw tau thov kom ua tau zoo ntawm cov nqaj acceleration26.Txawm li cas los xij, qhov muaj lithium-ion beam tam sim no raug txwv rau 100 µA.Nws tau raug thov kom siv 1 mA ntawm Li3 + 27, tab sis qhov ion beam tam sim no tsis tau lees paub los ntawm txoj kev no.Hais txog kev siv zog, lithium beam accelerators tsis tuaj yeem sib tw nrog proton beam accelerators uas nws cov peak proton tam sim no tshaj 10 mA28.
Txhawm rau siv lub tshuab hluav taws xob me me me me raws li cov kab hluav taws xob lithium-ion, nws yog qhov zoo los tsim kom muaj kev siv siab ua kom tsis muaj ions.Cov ions tau nrawm thiab coj los ntawm electromagnetic rog, thiab qib siab dua ua rau muaj kev nrawm dua.Li-ion beam tsav tsheb yuav tsum tau Li3 + ncov tam sim no tshaj 10 mA.
Hauv kev ua haujlwm no, peb ua kom pom qhov nrawm ntawm Li3+ kab teeb nrog cov kab hluav taws xob siab tshaj plaws txog li 35 mA, uas yog piv rau cov qib proton accelerators.Tus thawj lithium ion beam tau tsim los siv laser ablation thiab Direct Plasma Implantation Scheme (DPIS) Ameslikas tsim los kom ceev C6+.Ib qho kev cai-tsim xov tooj cua zaus quadrupole linac (RFQ linac) tau tsim siv plaub-rod resonant qauv.Peb tau txheeb xyuas tias cov kab nrawm nrawm muaj qhov ntsuas siab purity beam zog.Thaum lub Li3+ beam raug ntes tau zoo thiab nrawm los ntawm lub xov tooj cua zaus (RF) accelerator, ntu tom ntej linac (accelerator) yog siv los muab lub zog xav tau los ua kom muaj zog neutron flux los ntawm lub hom phiaj.
Lub acceleration ntawm high efficiency ions yog ib tug zoo tsim technology.Lub luag haujlwm tseem ceeb ntawm kev paub txog lub tshuab hluav taws xob tshiab uas muaj txiaj ntsig zoo heev yog los tsim kom muaj ntau tus lej ntawm cov lithium ions tag nrho thiab tsim cov qauv pawg uas muaj cov ion pulses synchronized nrog lub voj voog RF hauv lub accelerator.Cov txiaj ntsig ntawm kev sim tsim los ua kom tiav lub hom phiaj no tau piav qhia nyob rau hauv peb ntu nram qab no: (1) tiam ntawm qhov tsis muaj lithium-ion beam, (2) beam acceleration siv lub RFQ linac tshwj xeeb tsim, thiab (3) acceleration ntawm kev soj ntsuam. ntawm beam los xyuas nws cov ntsiab lus.Ntawm Brookhaven National Laboratory (BNL), peb tau tsim qhov kev sim teeb tsa hauv daim duab 2.
Txheej txheem cej luam ntawm kev sim teeb tsa rau kev soj ntsuam nrawm ntawm lithium beams (pib los ntawm Inkscape, 1.0.2, https://inkscape.org/).Los ntawm txoj cai mus rau sab laug, laser-ablative plasma yog tsim nyob rau hauv lub laser-target kev sib cuam tshuam chamber thiab xa mus rau lub RFQ linac.Thaum nkag mus rau RFQ accelerator, cov ions raug cais tawm ntawm cov ntshav thiab txhaj rau hauv lub RFQ accelerator los ntawm ib qho hluav taws xob tam sim ntawd tsim los ntawm 52 kV voltage qhov sib txawv ntawm cov electrode extraction thiab RFQ electrode hauv thaj tsam drift.Cov ions rho tawm tau nrawm ntawm 22 keV / n mus rau 204 keV / n siv 2 meter ntev RFQ electrodes.Lub transformer tam sim no (CT) ntsia ntawm qhov tso zis ntawm RFQ linac muab kev ntsuas tsis muaj kev puas tsuaj ntawm ion beam tam sim no.Lub beam yog tsom los ntawm peb quadrupole hlau nplaum thiab coj mus rau ib tug dipole hlau nplaum, uas cais thiab coj lub Li3+ beam mus rau hauv lub detector.Tom qab lub slit, ib tug retractable yas scintillator thiab lub khob Faraday (FC) nrog ib tug bias mus txog rau -400 V yog siv los xyuas kom meej lub accelerating beam.
Txhawm rau tsim kom muaj ionized lithium ions (Li3+), nws yog qhov tsim nyog los tsim cov ntshav nrog qhov kub siab tshaj nws lub zog thib peb ionization (122.4 eV).Peb tau sim siv laser ablation los tsim cov plasma kub.Hom laser ion no feem ntau tsis yog siv los tsim cov kab teeb lithium ion vim lithium hlau reactive thiab yuav tsum tau tuav tshwj xeeb.Peb tau tsim lub hom phiaj kev thauj khoom kom txo qis noo noo thiab huab cua paug thaum txhim kho lithium ntawv ci hauv lub tshuab nqus tsev laser sib cuam tshuam chamber.Tag nrho cov kev npaj ntawm cov ntaub ntawv tau ua nyob rau hauv ib qho chaw tswj ntawm qhuav argon.Tom qab cov ntawv ci lithium tau teeb tsa hauv lub hom phiaj laser chamber, cov ntawv ci tau irradiated nrog pulsed Nd:YAG laser hluav taws xob ntawm lub zog ntawm 800 mJ ib mem tes.Ntawm qhov tsom mus rau lub hom phiaj, lub zog laser lub zog yog kwv yees li 1012 W / cm2.Plasma yog tsim thaum lub laser pulsed rhuav tshem lub hom phiaj hauv lub tshuab nqus tsev.Thaum lub sij hawm tag nrho 6 ns laser mem tes, cov ntshav plasma tseem kub, feem ntau yog vim cov txheej txheem rov qab bremsstrahlung.Txij li thaum tsis muaj kev txwv sab nraud yog siv rau lub sijhawm cua sov, lub plasma pib nthuav dav hauv peb qhov ntev.Thaum lub plasma pib nthuav dav ntawm lub hom phiaj nto, qhov nruab nrab ntawm qhov loj ntawm lub plasma tau txais ib qho kev tshaj tawm perpendicular rau lub hom phiaj nto nrog lub zog ntawm 600 eV / n.Tom qab cua sov, lub plasma tseem txav mus rau hauv axial kev taw qhia los ntawm lub hom phiaj, nthuav isotropically.
Raws li pom nyob rau hauv daim duab 2, lub ablation plasma nthuav mus rau hauv lub tshuab nqus tsev ntim ib puag ncig ntawm lub thawv hlau uas muaj peev xwm zoo ib yam li lub hom phiaj.Yog li, lub plasma drifts los ntawm thaj av-dawb cheeb tsam mus rau RFQ accelerator.Ib qho axial magnetic teb yog siv nruab nrab ntawm lub laser irradiation chamber thiab RFQ linac los ntawm kev siv lub solenoid coil qhov txhab nyob ib ncig ntawm lub tshuab nqus tsev chamber.Lub teb sib nqus ntawm lub solenoid suppresses lub radial expansion ntawm drifting plasma thiaj li yuav tswj tau cov ntshav siab ceev thaum lub sij hawm xa mus rau RFQ aperture.Ntawm qhov tod tes, cov plasma txuas ntxiv nthuav dav hauv axial kev taw qhia thaum lub caij drift, tsim cov ntshav elongated.Lub siab tsis ncaj ncees yog siv rau lub nkoj hlau uas muaj cov ntshav nyob rau hauv pem hauv ntej ntawm qhov chaw nres nkoj tawm ntawm RFQ inlet.Qhov kev tsis txaus ntseeg tau raug xaiv los muab qhov xav tau 7Li3+ txhaj tshuaj rau kev nrawm nrawm los ntawm RFQ linac.
Cov txiaj ntsig ablation ntshav muaj tsis tsuas yog 7Li3+, tab sis kuj tseem muaj lithium hauv lwm lub xeev thiab cov khoom muaj kuab paug, uas yog thauj mus rau RFQ linear accelerator.Ua ntej kev sim nrawm siv RFQ linac, kev tshawb xyuas offline-of-flight (TOF) tau ua los kawm txog cov muaj pes tsawg leeg thiab lub zog faib ntawm ions hauv cov ntshav.Cov ncauj lus kom ntxaws analytical teeb thiab soj ntsuam kev faib tawm ntawm lub xeev tau piav qhia hauv Cov Txheej Txheem.Kev tsom xam pom tias 7Li3+ ions yog cov ntsiab lus tseem ceeb, suav txog li 54% ntawm tag nrho cov khoom, raws li qhia hauv daim duab 3. Raws li kev txheeb xyuas, 7Li3+ ion tam sim no ntawm ion beam output point yog kwv yees li ntawm 1.87 mA.Thaum lub sijhawm ntsuas nrawm, 79 mT solenoid teb yog siv rau cov ntshav plasma nthuav dav.Raws li qhov tshwm sim, 7Li3+ tam sim no tau muab rho tawm los ntawm cov ntshav ntshav thiab pom ntawm lub ntsuas ntsuas tau nce los ntawm ib qho ntawm 30.
Cov feem ntawm ions hauv laser-generated plasma tau los ntawm lub sij hawm-ntawm-flight tsom xam.Lub 7Li1+ thiab 7Li2+ ions ua 5% thiab 25% ntawm ion beam, feem.Qhov kuaj pom feem ntawm 6Li hais pom zoo nrog cov ntsiab lus ntawm 6Li (7.6%) hauv lub hom phiaj lithium foil hauv qhov kev sim ua yuam kev.Cov pa oxygen me ntsis (6.2%) tau pom, feem ntau yog O1 + (2.1%) thiab O2 + (1.5%), uas tej zaum yuav yog vim oxidation ntawm qhov chaw ntawm lithium foil phiaj.
Raws li tau hais dhau los, lithium plasma drifts hauv thaj av tsis muaj chaw ua ntej nkag mus rau RFQ linac.Cov tswv yim ntawm RFQ linac muaj 6 hli txoj kab uas hla hauv lub thawv hlau, thiab qhov tsis sib xws yog 52 kV.Txawm hais tias RFQ electrode voltage hloov sai ± 29 kV ntawm 100 MHz, qhov voltage ua rau axial acceleration vim RFQ accelerator electrodes muaj qhov nruab nrab ntawm xoom.Vim lub zog hluav taws xob tsim nyob rau hauv 10 hli qhov sib txawv ntawm lub aperture thiab ntug ntawm RFQ electrode, tsuas yog cov plasma ions zoo raug rho tawm ntawm cov ntshav ntawm lub aperture.Hauv cov txheej txheem kev xa khoom ion ib txwm muaj, ions raug cais tawm ntawm cov ntshav los ntawm lub chaw hluav taws xob ntawm qhov kev ncua deb ntawm RFQ accelerator thiab tom qab ntawd tsom mus rau RFQ aperture los ntawm lub teeb tsom teeb.Txawm li cas los xij, rau cov kab mob hnyav hnyav uas yuav tsum tau muaj rau qhov muaj zog neutron, tsis yog-linear repulsive rog vim qhov chaw them nqi tuaj yeem ua rau cov kab teeb tseem ceeb tam sim no poob rau hauv kev thauj khoom ion, txwv lub ncov tam sim no uas tuaj yeem ua kom nrawm dua.Hauv peb cov DPIS, cov ions siab siv tau thauj mus los ua cov ntshav ntws ncaj qha mus rau qhov chaw tawm ntawm RFQ aperture, yog li tsis muaj qhov poob ntawm ion beam vim qhov chaw them nqi.Thaum lub sijhawm ua qauv qhia no, DPIS tau siv rau lub teeb lithium-ion thawj zaug.
Cov qauv RFQ tau tsim los rau kev tsom thiab ua kom lub zog qis zog siab tam sim no ion kab teeb thiab tau dhau los ua tus qauv rau thawj qhov kev ua kom nrawm.Peb siv RFQ kom nrawm 7Li3+ ions los ntawm kev cog qoob loo ntawm 22 keV / n txog 204 keV / n.Txawm hais tias lithium thiab lwm yam khoom uas muaj qis dua hauv cov ntshav kuj tau muab rho tawm los ntawm cov ntshav thiab txhaj rau hauv RFQ aperture, RFQ linac tsuas yog nrawm ions nrog tus nqi-rau-mass piv (Q / A) ze rau 7Li3+.
Ntawm daim duab.Daim duab 4 qhia cov waveforms kuaj pom los ntawm tam sim no transformer (CT) ntawm cov zis ntawm RFQ linac thiab Faraday khob (FC) tom qab tshuaj xyuas cov hlau nplaum, raws li qhia hauv daim duab.2. Lub sijhawm hloov pauv ntawm cov teeb liab tuaj yeem txhais tau tias qhov sib txawv ntawm lub sijhawm ya davhlau ntawm qhov chaw ntawm lub tshuab ntes.Lub ncov ion tam sim no ntsuas ntawm CT yog 43 mA.Nyob rau hauv txoj hauj lwm RT, cov kab hluav taws xob sau npe tuaj yeem tsis tsuas yog ions nrawm rau lub zog suav, tab sis kuj muaj ions uas tsis yog 7Li3+, uas tsis txaus nrawm.Txawm li cas los xij, qhov zoo sib xws ntawm cov ntaub ntawv ion tam sim no pom los ntawm QD thiab PC qhia tias tam sim no ion feem ntau muaj nrawm 7Li3+, thiab qhov txo qis ntawm tus nqi siab tshaj ntawm tam sim no ntawm PC yog tshwm sim los ntawm kev poob qis thaum lub sij hawm ion hloov ntawm QD thiab PC.Losses Qhov no kuj tau lees paub los ntawm lub hnab ntawv simulation.Txhawm rau ntsuas qhov 7Li3+ beam tam sim no, lub beam raug tshuaj xyuas nrog dipole hlau nplaum raws li tau piav qhia hauv ntu tom ntej.
Oscillograms ntawm lub nrawm nrawm tau sau tseg hauv qhov chaw ntes CT (dub nkhaus) thiab FC (liab nkhaus).Cov kev ntsuas no tau tshwm sim los ntawm kev tshawb pom ntawm laser hluav taws xob los ntawm photodetector thaum lub sij hawm laser plasma tiam.Qhov nkhaus dub qhia qhov waveform ntsuas ntawm CT txuas nrog RFQ linac tso zis.Vim nws qhov sib thooj rau RFQ linac, lub tshuab ntes khaws 100 MHz RF suab nrov, yog li 98 MHz qis dhau FFT lim tau siv los tshem tawm 100 MHz resonant RF teeb liab superimposed ntawm lub teeb liab nrhiav pom.Qhov nkhaus liab qhia qhov waveform ntawm FC tom qab cov hlau nplaum analytical directs 7Li3+ ion beam.Hauv qhov chaw sib nqus no, sib nrug ntawm 7Li3+, N6+ thiab O7+ tuaj yeem thauj tau.
Lub ion beam tom qab lub RFQ linac yog tsom los ntawm ib tug series ntawm peb quadrupole tsom hlau nplaum thiab ces soj ntsuam los ntawm dipole hlau nplaum kom cais impurities nyob rau hauv lub ion beam.Qhov sib nqus ntawm 0.268 T coj 7Li3+ kab teeb rau hauv FC.Qhov kev tshawb nrhiav waveform ntawm qhov sib nqus no yog pom raws li qhov nkhaus liab hauv daim duab 4. Lub peak beam tam sim no nce mus txog 35 mA, uas yog ntau tshaj 100 npaug tshaj li cov kab hluav taws xob Li3+ uas muaj nyob rau hauv cov pa hluav taws xob uas twb muaj lawm.Lub beam mem tes dav yog 2.0 µs ntawm qhov dav dav ntawm ib nrab siab tshaj plaws.Kev tshawb pom ntawm 7Li3+ beam nrog lub dipole magnetic teb qhia tau hais tias kev vam meej bunching thiab beam acceleration.Lub ion beam tam sim no kuaj pom los ntawm FC thaum kuaj xyuas qhov sib nqus ntawm lub dipole yog pom hauv daim duab 5. Ib lub ncov huv si tau pom, zoo sib cais los ntawm lwm cov peaks.Txij li thaum tag nrho cov ions tau nrawm rau lub zog tsim los ntawm RFQ linac muaj qhov ceev tib yam, ion kab teeb nrog tib Q / A nyuaj rau kev sib cais los ntawm dipole magnetic teb.Yog li, peb tsis tuaj yeem paub qhov txawv 7Li3+ los ntawm N6+ lossis O7+.Txawm li cas los xij, tus nqi ntawm impurities tuaj yeem kwv yees los ntawm cov xeev nyob sib ze.Piv txwv li, N7+ thiab N5+ tuaj yeem sib cais tau yooj yim, thaum N6+ yuav yog ib feem ntawm impurity thiab xav tias yuav muaj nyob rau hauv tib qhov nyiaj li N7+ thiab N5+.Qhov kwv yees cov pa phem yog kwv yees li 2%.
Beam tivthaiv spectra tau los ntawm kev tshuaj xyuas lub dipole magnetic teb.Lub ncov ntawm 0.268 T sib raug rau 7Li3+ thiab N6+.Lub ncov dav nyob ntawm qhov loj ntawm lub nqaj ntawm qhov slit.Txawm hais tias dav peaks, 7Li3+ cais tau zoo los ntawm 6Li3+, O6+, thiab N5+, tab sis cais tsis zoo ntawm O7+ thiab N6+.
Ntawm qhov chaw ntawm FC, lub nqaj profile tau lees paub nrog lub plug-in scintillator thiab kaw nrog lub koob yees duab ceev ceev raws li qhia hauv daim duab 6. Lub 7Li3+ pulsed beam nrog tam sim no ntawm 35 mA tau pom tias yuav tsum tau nrawm mus rau kev suav RFQ. Lub zog ntawm 204 keV / n, uas sib haum rau 1.4 MeV, thiab xa mus rau FC ntes.
Beam profile pom ntawm lub vijtsam ua ntej FC scintillator (xim los ntawm Fiji, 2.3.0, https://imagej.net/software/fiji/).Cov hlau nplaum sib nqus ntawm cov hlau nplaum dipole analytical tau raug kho los tswj qhov nrawm ntawm Li3+ ion beam rau lub zog tsim RFQ.Cov dots xiav hauv thaj chaw ntsuab yog tshwm sim los ntawm cov khoom siv scintillator tsis zoo.
Peb tau ua tiav lub cim ntawm 7Li3+ ions los ntawm laser ablation ntawm qhov chaw ntawm cov khoom lithium ntawv ci, thiab lub siab tam sim no ion beam raug ntes thiab nrawm nrog ib qho tshwj xeeb tsim RFQ linac siv DPIS.Ntawm lub zog hluav taws xob ntawm 1.4 MeV, lub ncov tam sim no ntawm 7Li3+ tau mus txog ntawm FC tom qab kev tshuaj xyuas ntawm cov hlau nplaum yog 35 mA.Qhov no tau lees paub tias qhov tseem ceeb tshaj plaws ntawm kev siv cov neutron qhov chaw nrog inverse kinematics tau raug siv los sim.Nyob rau hauv ib feem ntawm daim ntawv no, tag nrho cov tsim ntawm ib tug compact neutron qhov chaw yuav tham, nrog rau cov high zog accelerators thiab neutron phiaj chaw nres tsheb.Cov qauv tsim yog raws li cov txiaj ntsig tau nrog cov tshuab uas twb muaj lawm hauv peb lub chaw kuaj mob.Nws yuav tsum tau muab sau tseg tias lub ncov tam sim no ntawm lub ion beam yuav tsum tau ntxiv los ntawm shortening qhov deb ntawm cov lithium ntawv ci thiab RFQ linac.Rice.7 qhia txog tag nrho lub tswv yim ntawm cov lus pom zoo ntawm cov neutron qhov chaw ntawm lub accelerator.
Lub tswv yim tsim ntawm lub tswv yim compact neutron qhov chaw ntawm lub accelerator (kos los ntawm Freecad, 0.19, https://www.freecadweb.org/).Los ntawm sab xis mus rau sab laug: laser ion qhov chaw, solenoid hlau nplaum, RFQ linac, nruab nrab lub zog hluav taws xob hloov hluav taws xob (MEBT), IH linac, thiab kev sib cuam tshuam chamber rau neutron tiam.Kev tiv thaiv hluav taws xob yog muab feem ntau nyob rau hauv kev taw qhia pem hauv ntej vim qhov kev taw qhia nqaim ntawm cov kab hluav taws xob tsim tawm.
Tom qab RFQ linac, ntxiv acceleration ntawm Inter-digital H-structure (IH linac) 30 linac yog npaj.IH linacs siv π-hom drift raj qauv los muab cov hluav taws xob hluav taws xob siab gradients dhau ntawm qee qhov kev nrawm.Txoj kev tshawb nrhiav tswv yim tau ua raws li 1D longitudinal dynamics simulation thiab 3D plhaub simulation.Kev suav qhia tau hais tias 100 MHz IH linac nrog qhov tsim nyog drift tube voltage (tsawg dua 450 kV) thiab cov hlau nplaum muaj zog tuaj yeem ua kom lub zog ntawm 40 mA ntawm 1.4 mus rau 14 MeV ntawm qhov deb ntawm 1.8 m.Kev faib hluav taws xob nyob rau qhov kawg ntawm cov khoom siv nrawm yog kwv yees li ± 0.4 MeV, uas tsis cuam tshuam rau lub zog spectrum ntawm neutrons uas tsim los ntawm lub hom phiaj ntawm kev hloov pauv neutron.Tsis tas li ntawd, lub beam emissivity yog tsawg txaus los tsom lub beam mus rau ib tug me me beam chaw tshaj li ib txwm yuav tsum tau rau ib tug nruab nrab lub zog thiab loj quadrupole hlau nplaum.Hauv nruab nrab lub zog nqaj hlau (MEBT) kis tau tus mob ntawm RFQ linac thiab IH linac, lub beamforming resonator yog siv los tswj cov qauv beamforming.Peb quadrupole hlau nplaum yog siv los tswj qhov loj ntawm sab beam.Cov tswv yim tsim qauv no tau siv ntau yam accelerators31,32,33.Tag nrho qhov ntev ntawm tag nrho cov kab ke los ntawm qhov chaw ion mus rau lub hom phiaj chamber yog kwv yees tsawg dua 8 m, uas tuaj yeem haum rau hauv cov qauv tsheb thauj khoom semi-trailer.
Lub hom phiaj ntawm kev hloov pauv neutron yuav raug ntsia ncaj qha tom qab cov kab hluav taws xob accelerator.Peb sib tham txog lub hom phiaj chaw nres tsheb tsim raws li cov kev tshawb fawb yav dhau los siv inverse kinematic scenarios23.Tshaj tawm cov phiaj xwm hloov dua siab tshiab suav nrog cov khoom siv (polypropylene (C3H6) thiab titanium hydride (TiH2)) thiab lub hom phiaj gaseous.Txhua lub hom phiaj muaj qhov zoo thiab qhov tsis zoo.Cov hom phiaj ruaj khov tso cai rau kev tswj cov tuab tuab.Qhov thinner lub hom phiaj, qhov tseeb dua qhov kev npaj ntawm neutron ntau lawm.Txawm li cas los xij, cov hom phiaj zoo li no tseem yuav muaj qee qhov tsis xav tau kev tawm tsam nuclear thiab hluav taws xob.Ntawm qhov tod tes, lub hom phiaj hydrogen tuaj yeem muab qhov chaw huv huv los ntawm kev tshem tawm cov khoom tsim tawm ntawm 7Be, cov khoom tseem ceeb ntawm cov tshuaj tiv thaiv nuclear.Txawm li cas los xij, hydrogen muaj lub peev xwm tsis muaj zog thiab yuav tsum muaj lub cev loj nyob deb kom txaus tso tawm lub zog.Qhov no yog qhov tsis zoo me ntsis rau kev ntsuas TOF.Tsis tas li ntawd, yog tias ib zaj duab xis nyias siv los kaw lub hom phiaj hydrogen, nws yuav tsum tau coj mus rau hauv tus account lub zog poob ntawm gamma rays generated los ntawm nyias zaj duab xis thiab qhov teeb meem lithium beam.
LICORNE siv lub hom phiaj polypropylene thiab lub hom phiaj tau hloov kho rau hydrogen cell kaw nrog tantalum ntawv ci.Piv txwv li cov kab hluav taws xob tam sim no ntawm 100 nA rau 7Li34, ob lub hom phiaj tuaj yeem tsim tau txog 107 n / s / sr.Yog tias peb siv qhov kev thov neutron yield hloov dua siab tshiab rau peb qhov kev thov neutron, ces lub teeb lithium-tsav ntawm 7 × 10-8 C tuaj yeem tau txais rau txhua lub laser pulse.Qhov no txhais tau hais tias kev tua lub laser tsuas yog ob zaug ib pliag ua rau 40% ntau dua neutrons dua li LICORNE tuaj yeem tsim nyob rau hauv ib thib ob nrog cov nqaj txuas ntxiv.Tag nrho cov flux tuaj yeem yooj yim nce los ntawm kev ua kom muaj zog ntawm lub laser.Yog tias peb xav tias muaj 1 kHz laser system nyob rau hauv kev ua lag luam, qhov nruab nrab neutron flux tuaj yeem yooj yim ntsuas txog li 7 × 109 n / s / sr.
Thaum peb siv cov txheej txheem siab rov ua dua nrog cov hom phiaj yas, nws yog ib qho tsim nyog los tswj cov cua kub ntawm lub hom phiaj vim tias, piv txwv li, polypropylene muaj qhov melting point ntawm 145-175 ° C thiab qis thermal conductivity ntawm 0.1-0.22 W / m/K.Rau 14 MeV lithium-ion beam, 7 µm tuab polypropylene lub hom phiaj yog txaus los txo cov nqaj zog mus rau qhov chaw pib (13.098 MeV).Muab rau hauv tus account tag nrho cov nyhuv ntawm ions generated los ntawm ib tug laser txhaj rau lub hom phiaj, lub zog tso tawm ntawm lithium ions los ntawm polypropylene yog kwv yees ntawm 64 mJ / mem tes.Piv txwv tias tag nrho cov zog raug xa mus rau hauv lub voj voog nrog txoj kab uas hla ntawm 10 hli, txhua tus mem tes sib haum mus rau qhov kub siab ntawm kwv yees li 18 K / mem tes.Lub zog tso tawm ntawm lub hom phiaj polypropylene yog raws li kev xav yooj yim uas txhua lub zog poob yog khaws cia raws li cov cua sov, tsis muaj hluav taws xob lossis lwm yam kub poob.Txij li thaum nce tus naj npawb ntawm pulses ib ob yuav tsum tau tshem tawm ntawm tshav kub buildup, peb siv tau strip lub hom phiaj kom tsis txhob muaj zog tso tawm ntawm tib point23.Piv txwv li 10 hli beam qhov chaw ntawm lub hom phiaj nrog lub laser repetition tus nqi ntawm 100 Hz, scanning ceev ntawm daim kab xev polypropylene yuav yog 1 m / s.Kev rov ua dua siab dua tuaj yeem ua tau yog tias kab teeb pom kev sib tshooj raug tso cai.
Peb kuj tau tshawb xyuas lub hom phiaj nrog cov roj teeb hydrogen, vim tias cov kab hluav taws xob muaj zog tuaj yeem siv tau yam tsis muaj kev puas tsuaj rau lub hom phiaj.Cov kab hluav taws xob neutron tuaj yeem hloov kho tau yooj yim los ntawm kev hloov qhov ntev ntawm cov pa roj chamber thiab cov hydrogen siab sab hauv.Nyias hlau foils feem ntau yog siv nyob rau hauv accelerators cais lub gaseous cheeb tsam ntawm lub hom phiaj ntawm lub tshuab nqus tsev vacuum.Yog li ntawd, nws yog ib qho tsim nyog yuav tsum tau nce lub zog ntawm qhov teeb meem lithium-ion beam thiaj li yuav tau them nyiaj rau lub zog poob ntawm cov ntawv ci.Lub hom phiaj sib dhos tau piav qhia hauv daim ntawv tshaj tawm 35 muaj lub thawv txhuas 3.5 cm ntev nrog H2 roj siab ntawm 1.5 atm.Lub 16.75 MeV lithium ion beam nkag mus rau hauv lub roj teeb los ntawm huab cua-txias 2.7 µm Ta foil, thiab lub zog ntawm lithium ion beam ntawm lub roj teeb kawg yog decelerated mus rau qhov pib cov tshuaj tiv thaiv.Txhawm rau nce lub zog ntawm lub zog ntawm lithium-ion roj teeb los ntawm 14.0 MeV rau 16.75 MeV, IH linac yuav tsum tau ua kom ntev li ntawm 30 cm.
Cov emission ntawm neutrons los ntawm cov roj cell lub hom phiaj kuj tau kawm.Rau cov lus hais saum toj no LICORNE roj lub hom phiaj, GEANT436 simulations qhia tau hais tias cov neutrons uas muaj zog heev yog tsim nyob rau hauv lub khob hliav qab, raws li qhia hauv daim duab 1 hauv [37].Kev siv 35 qhia tau hais tias lub zog ntau ntawm 0.7 txog 3.0 MeV nrog lub siab tshaj plaws lub khob qhib ntawm 19.5 ° txheeb ze rau cov kev taw qhia ntawm kev nthuav tawm ntawm lub ntsiab nqaj.Highly oriented neutrons tuaj yeem txo cov nqi ntawm cov ntaub thaiv npog ntawm feem ntau cov ces kaum, txo qhov hnyav ntawm cov qauv thiab muab kev yooj yim dua hauv kev teeb tsa cov khoom ntsuas.Los ntawm qhov pom ntawm kev tiv thaiv hluav taws xob, ntxiv rau cov neutrons, lub hom phiaj gaseous no emits 478 keV gamma rays isotropically nyob rau hauv centroid coordinate system38.Cov γ-rays no yog tsim los ntawm 7Be lwj thiab 7Li deexcitation, uas tshwm sim thaum thawj Li beam hits lub qhov rais input Ta.Txawm li cas los xij, los ntawm kev ntxiv cov tuab 35 Pb / Cu cylindrical collimator, keeb kwm yav dhau tuaj yeem txo qis.
Raws li lwm lub hom phiaj, ib tus tuaj yeem siv lub qhov rais plasma [39, 40], uas ua rau nws muaj peev xwm ua tiav qhov siab hydrogen siab thiab thaj tsam me me ntawm cov cim neutron, txawm tias nws tsis zoo rau cov hom phiaj.
Peb tab tom tshawb nrhiav neutron hloov dua siab tshiab lub hom phiaj rau kev xav tau lub zog xa tawm thiab kab teeb loj ntawm lithium ion beam siv GEANT4.Peb cov kev simulations qhia txog kev faib tawm ntawm neutron zog thiab kev faib tawm rau cov hom phiaj hydrogen hauv cov ntaub ntawv saum toj no.Nyob rau hauv txhua lub hom phiaj, cov neutrons uas muaj kev taw qhia siab tuaj yeem tsim los ntawm kev sib hloov kinematic cov tshuaj tiv thaiv uas tau tsav los ntawm lub zog 7Li3+ nqaj ntawm lub hom phiaj hydrogen-nplua nuj.Yog li ntawd, cov khoom siv neutron tshiab tuaj yeem siv tau los ntawm kev sib txuas cov thev naus laus zis uas twb muaj lawm.
Lub laser irradiation tej yam kev mob reproduced ion beam tiam thwmsim ua ntej lub ceev ua qauv qhia.Lub laser yog ib lub desktop nanosecond Nd:YAG system nrog lub zog laser zog ntawm 1012 W / cm2, ib qho tseem ceeb wavelength ntawm 1064 nm, lub zog ntawm 800 mJ, thiab lub sijhawm mem tes ntawm 6 ns.Qhov chaw txoj kab uas hla ntawm lub hom phiaj yog kwv yees li ntawm 100 µm.Vim tias lithium hlau (Alfa Aesar, 99.9% ntshiab) yog mos heev, cov khoom txiav raug nias rau hauv pwm.Ntawv ci qhov ntev 25 hli × 25 hli, thickness 0.6 hli.Crater-zoo li kev puas tsuaj tshwm sim ntawm qhov chaw ntawm lub hom phiaj thaum lub laser hits nws, yog li lub hom phiaj yog tsiv los ntawm lub motorized platform los muab ib feem tshiab ntawm lub hom phiaj nto nrog txhua laser txhaj.Txhawm rau kom tsis txhob rov ua dua vim cov roj seem, lub siab nyob hauv lub chamber tau khaws cia hauv qab qhov ntau ntawm 10-4 Pa.
Thawj qhov ntim ntawm lub laser plasma yog me me, vim qhov loj ntawm qhov chaw laser yog 100 μm thiab nyob rau hauv 6 ns tom qab nws tiam.Lub ntim tuaj yeem raug coj los ua qhov tseeb thiab nthuav dav.Yog hais tias tus ntes tau muab tso rau ntawm qhov deb xm los ntawm lub hom phiaj nto, ces lub teeb liab tau txais kev sib raug zoo: ion tam sim no I, ion tuaj txog lub sij hawm t, thiab mem tes dav τ.
Lub plasma generated tau kawm los ntawm TOF txoj kev nrog FC thiab lub zog ion analyzer (EIA) nyob ntawm qhov deb ntawm 2.4 m thiab 3.85 m ntawm lub hom phiaj laser.Lub FC muaj cov kab sib cais sib cais los ntawm -5 kV los tiv thaiv electrons.Lub EIA muaj 90 degree electrostatic deflector uas muaj ob lub coaxial hlau cylindrical electrodes nrog tib voltage tab sis opposite polarity, zoo rau sab nraud thiab tsis zoo rau sab hauv.Lub plasma expanding yog coj mus rau hauv lub deflector qab lub qhov thiab deflected los ntawm hluav taws xob teb hla lub tog raj kheej.Ions txaus siab rau txoj kev sib raug zoo E/z = eKU raug kuaj pom siv Secondary Electron Multiplier (SEM) (Hamamatsu R2362), qhov twg E, z, e, K, thiab U yog lub zog ion, lub xeev tus nqi, thiab tus nqi yog EIA geometric yam. .electrons, ntsig txog, thiab muaj peev xwm sib txawv ntawm cov electrodes.Los ntawm kev hloov qhov hluav taws xob hla lub deflector, ib tus tuaj yeem tau txais lub zog thiab them nqi faib ntawm ions hauv cov ntshav.Lub cheb voltage U / 2 EIA yog nyob rau hauv thaj tsam ntawm 0.2 V rau 800 V, uas sib raug rau lub zog ion nyob rau hauv thaj tsam ntawm 4 eV txog 16 keV ib lub xeev them.
Cov kev faib tawm ntawm lub xeev tus nqi ntawm cov ions soj ntsuam nyob rau hauv cov xwm txheej ntawm laser irradiation piav nyob rau hauv seem "Tsim ntawm tag nrho stripped lithium beams" yog qhia nyob rau hauv daim duab.8.
Kev soj ntsuam ntawm kev faib tawm ntawm lub xeev tus nqi ntawm ions.Ntawm no yog ion tam sim no ntom ntom profile soj ntsuam nrog EIA thiab ntsuas ntawm 1 m ntawm lithium ntawv ci siv qhov sib npaug.(1) thiab (2).Siv lub laser irradiation tej yam kev mob piav nyob rau hauv lub "Tsim ntawm ib tug ua tiav Exfoliated Lithium Beam" seem.Los ntawm kev sib koom ua ke txhua qhov ceev tam sim no, qhov kev faib ua feem ntawm ions hauv cov ntshav tau suav nrog, pom hauv daim duab 3.
Laser ion qhov chaw tuaj yeem xa cov kab mob siab ntau mA ion beam nrog tus nqi siab.Txawm li cas los xij, beam xa khoom yog qhov nyuaj heev vim qhov chaw them nqi repulsion, yog li nws tsis tau siv dav.Nyob rau hauv cov txheej txheem ib txwm muaj, ion beams raug rho tawm los ntawm cov ntshav thiab thauj mus rau thawj accelerator raws kab kab nrog ob peb tsom hlau nplaum los tsim cov ion beam raws li lub peev xwm khaws cov accelerator.Nyob rau hauv qhov chaw them nqi quab yuam kab teeb, cov kab teeb diverge non-linearly, thiab loj beam poob raug pom, tshwj xeeb tshaj yog nyob rau hauv cheeb tsam ntawm tsawg tshaj tawm.Txhawm rau kov yeej qhov teeb meem no hauv kev txhim kho cov pa roj carbon accelerators kho mob, DPIS41 beam xa tawm tshiab tau npaj siab.Peb tau siv cov txheej txheem no los ua kom lub zog muaj zog lithium-ion beam los ntawm qhov chaw neutron tshiab.
Raws li qhia hauv daim duab.4, qhov chaw nyob rau hauv uas lub plasma yog generated thiab nthuav yog surrounded los ntawm ib tug hlau thawv.Qhov chaw nyob rau hauv qhov chaw txuas mus rau qhov nkag mus rau RFQ resonator, nrog rau qhov ntim hauv lub solenoid coil.Ib qhov hluav taws xob ntawm 52 kV tau siv rau lub thawv.Nyob rau hauv RFQ resonator, ions raug rub los ntawm lub peev xwm los ntawm 6 hli txoj kab uas hla qhov los ntawm grounding RFQ.Cov tsis-linear repulsive rog ntawm kab kab raug tshem tawm thaum cov ions raug thauj mus rau hauv lub xeev plasma.Tsis tas li ntawd, raws li tau hais los saum toj no, peb tau siv lub tshuab solenoid ua ke nrog DPIS los tswj thiab ua kom cov ions ntom ntom hauv qhov kev tshem tawm aperture.
Lub RFQ accelerator muaj lub tshuab nqus tsev cylindrical raws li qhia hauv daim duab.9 ib a.Hauv nws, plaub tus pas nrig ntawm cov hlau tsis muaj oxygen tau muab tso rau quadrupole-symmetrically nyob ib ncig ntawm lub nqaj axis (Fig. 9b).4 rods thiab chambers tsim ib tug resonant RF Circuit Court.Qhov induced RF teb tsim ib lub sij hawm sib txawv voltage hla tus pas nrig.Ions implanted longitudinally nyob ib ncig ntawm lub axis yog tuav tom qab ntawm lub quadrupole teb.Nyob rau tib lub sij hawm, lub ntsis ntawm tus pas nrig yog modulated los tsim ib tug axial hluav taws xob teb.Lub axial teb splits cov kab nrib txuas ntxiv mus rau hauv cov kab ntawm kab pulses hu ua beam.Txhua lub teeb muaj nyob rau hauv ib lub sijhawm RF lub voj voog (10 ns).Cov kab teeb uas nyob ib sab yog spaced raws li lub sijhawm xov tooj cua.Nyob rau hauv RFQ linac, ib tug 2 µs beam los ntawm ib tug laser ion qhov chaw yog hloov mus rau hauv ib theem ntawm 200 beams.Lub beam yog ces accelerated mus rau xam lub zog.
Linear accelerator RFQ.(a) (sab laug) Sab nraud saib ntawm RFQ linac chamber.(b) (txoj cai) Plaub-qhib electrode nyob rau hauv lub chamber.
Cov qauv tsim tsis tseem ceeb ntawm RFQ linac yog tus pas nrig voltage, resonant zaus, beam qhov radius, thiab electrode modulation.Xaiv qhov voltage ntawm tus pas nrig ± 29 kV kom nws cov hluav taws xob hluav taws xob qis dua qhov hluav taws xob tawg.Qhov qis dua qhov resonant zaus, qhov ntau dua qhov kev xav ntawm sab nraud thiab qhov me dua qhov nruab nrab acceleration teb.Loj aperture radii ua rau nws muaj peev xwm nce lub nqaj loj thiab, yog li ntawd, nce lub nqaj tam sim no vim qhov chaw me me ntawm cov nqi repulsion.Ntawm qhov tod tes, loj dua aperture radii xav tau ntau lub zog RF los ua lub zog RFQ linac.Tsis tas li ntawd, nws raug txwv los ntawm qhov yuav tsum tau ua kom zoo ntawm qhov chaw.Raws li cov kev sib npaug no, lub resonant zaus (100 MHz) thiab aperture radius (4.5 mm) raug xaiv rau high-tam sim no beam acceleration.Lub modulation yog xaiv los txo qis beam poob thiab maximize acceleration efficiency.Tus qauv tsim tau zoo ntau zaus los tsim RFQ linac tsim uas tuaj yeem ceev 7Li3+ ions ntawm 40 mA ntawm 22 keV / n txog 204 keV / n hauv 2 m.Lub zog RF ntsuas thaum lub sijhawm sim yog 77 kW.
RFQ linacs tuaj yeem nrawm ions nrog ib qho tshwj xeeb Q / A.Yog li ntawd, thaum soj ntsuam ib tug beam noj mus rau qhov kawg ntawm ib tug linear accelerator, nws yog tsim nyog los coj mus rau hauv tus account isotopes thiab lwm yam khoom.Tsis tas li ntawd, qhov xav tau ions, ib feem nrawm, tab sis nqis los nyob rau hauv cov xwm txheej ceev nyob rau hauv nruab nrab ntawm lub accelerator, tseem tuaj yeem ua tau raws li kev kaw cia thiab tuaj yeem thauj mus rau qhov kawg.Tsis xav rays uas tsis yog engineered 7Li3+ hais yog hu ua impurities.Hauv peb qhov kev sim, 14N6 + thiab 16O7 + impurities yog qhov kev txhawj xeeb tshaj plaws, txij li cov lithium hlau foil reacts nrog oxygen thiab nitrogen hauv huab cua.Cov ions no muaj Q / A piv uas tuaj yeem nrawm nrog 7Li3+.Peb siv cov hlau nplaum dipole cais cov kab hluav taws xob sib txawv thiab qhov zoo rau kev tsom xam tom qab RFQ linac.
Cov kab kab tom qab RFQ linac yog tsim los xa cov kab nrawm nrawm 7Li3+ mus rau FC tom qab dipole hlau nplaum.-400 V bias electrodes yog siv los tuav cov electrons thib ob hauv lub khob kom raug ntsuas qhov ion beam tam sim no.Nrog rau qhov optics no, cov ion trajectories tau muab cais ua dipoles thiab tsom mus rau ntau qhov chaw nyob ntawm Q / A.Vim muaj ntau yam xws li lub zog diffusion thiab qhov chaw them nqi repulsion, lub nqaj ntawm lub ntsej muag muaj qhov dav dav.Cov hom tsuas tuaj yeem sib cais yog tias qhov kev ncua deb ntawm txoj haujlwm focal ntawm ob hom ion ntau dua li qhov dav ntawm lub nqaj.Txhawm rau kom tau txais qhov kev daws teeb meem siab tshaj plaws, kab rov tav slit yog ntsia ze ntawm lub duav ntawm lub nqaj, qhov chaw ntawm lub nqaj yog xyaum ua kom muaj zog.Ib qho screen scintillation (CsI (Tl) los ntawm Saint-Gobain, 40 mm × 40 mm × 3 mm) raug ntsia nruab nrab ntawm lub qhov txiav thiab lub PC.Lub tshuab scintillator tau siv los txiav txim siab qhov me me tshaj plaws uas cov qauv tsim yuav tsum dhau los ntawm kev pom kev daws teeb meem thiab ua kom pom cov kab teeb pom kev zoo rau cov kab hluav taws xob hnyav tam sim no.Daim duab kab teeb ntawm lub scintillator yog kaw los ntawm CCD lub koob yees duab los ntawm lub qhov rais nqus tsev.Kho lub sij hawm raug lub qhov rais kom npog tag nrho beam mem tes dav.
Cov ntaub ntawv siv lossis txheeb xyuas hauv txoj kev tshawb fawb tam sim no muaj los ntawm cov kws sau ntawv raws li qhov kev thov tsim nyog.
Manke, I. et al.Peb-dimensional imaging ntawm magnetic domains.National koom haum.1, 125. https://doi.org/10.1038/ncomms1125 (2010).
Anderson, IS et al.Muaj peev xwm kawm txog cov khoom siv neutron ntawm cov accelerators.physics.Rep. 654, 1-58.https://doi.org/10.1016/j.physrep.2016.07.007 (2016).
Urchuoli, A. et al.Neutron-based xam microtomography: Pliobates cataloniae thiab Barberapithecus huerzeleri raws li kev kuaj mob.Yog lawm.J. Physics.anthropology.166, 987–993, ib.https://doi.org/10.1002/ajpa.23467 (2018).