Measurements of noninterceptive fluorescence profile monitor prototypes using 9 MeV deuterons

Measu emen s o nonin e cep i e luo escence p o ile moni o p o o ypes using 9 MeV deu e ons J. M. Ca mona,*I. Podade a, and A. Iba a Cen o de In es igaciones Ene ge ´ icas, Medioambien ales y Tecnolo ´gicas (CIEMAT), E-28040, Mad id, Spain A. Bocci, M. C. Jime ´nez-Ramos, J. Ga cı ´aLo ´pez, and Z. Abou-Haı ¨da Cen o Nacional de Acele ado es (CNA), E-41092, Se ille, Spain M. A. G. A ´l a ez and B. Fe na ´ndez Depa amen o de Fı ´sica A o ´mica, Molecula y Nuclea (FAMN), Uni e sidad de Se illa, E-41012, Se ille, Spain (Recei ed 1 Feb ua y 2011; published 17 July 2012) Two ypes o nonin e cep i e op ical moni o s, based on gas luo escence, ha e been designed o use on he Linea IFMIF P o o ype Accele a o (LIPAc) ha is cu en ly unde de elopmen (a 125 mA, 9 MeV, 175 MHz con inuous wa e deu e on beam). These diagnos ics o e a echnique o cha ac e ize he ans e se beam p o ile o medium o high cu en had on beams, wi hou in e cep ing he beam co e. This pape epo s on beam es s using he p o o ype moni o s de eloped o LIPAc. Tes s we e ca ied ou a an expe imen al line o he Cen o Nacional de Acele ado es cyclo on, using 9 MeV deu e ons wi h beam cu en s om 0.4 o 40 A. In addi ion, ans e se beam p o ile measu emen s we e pe o med unde high backg ound adia ion (e.g. gamma dose a e up o 83 mS =h). P elimina y c oss-checks wi h di e en p o ile s, as well as a sys ema ic scan o beam cu en and acuum p essu es and es s wi h di e en injec ed gases (ni ogen and xenon) ha e been pe o med. In his wo k, we p esen a b ie desc ip ion o he expe imen al se up and he i s measu emen s ob ained wi h hese p o o ype p o ile s plus a discussion o he i s analysis o he backg ound signal in a de ec o as a unc ion o adia ion backg ound. DOI: 10.1103/PhysRe STAB.15.072801 PACS numbe s: 29.20.Ej, 29.20.dg, 29.27.Fh I. INTRODUCTION A high powe beam, such as he 1.125 MW Linea IFMIF p o o ype Accele a o (LIPAc) beam [1], is po en- ially ha m ul o any in e cep i e diagnos ic (e en when ope a ed a a low du y cycle), especially i i in e cep s he beam co e. In such cases, nonin e cep i e diagnos ics a e p e e able. I is o eseen ha in he LIPAc, wo nonin e - cep i e beam p o ile s will be ins alled, one based on esidual gas luo escence and he o he on esidual gas ioniza ion. This p esen a icle ocuses on he luo escence beam p o ile . In gene al, beam pa icles passing h ough a acuum pipe may exci e esidual o injec ed gas pa icles in he acuum chambe and he beam pa h, he eby p oducing pho ons as a consequence o deexci a ion. The esul an ligh can be used o de e mine he beam p o ile wi hou he need o in e cep he beam. This echnique has p e iously been es ed on o he machines, e.g., he high ene gy p o on synch o on CERN-PS [2,3], he ela i is ic hea y ion collide RHIC [4], and he hea y ion GSI-UNILAC [5]. A p esen , se e al p ojec s in ol ing he cons uc ion and exploi a ion o high cu en and medium ene gy deu- e on accele a o s a e in p og ess (i.e., SARAF, IFMIF, SPIRAL2). These accele a o s p o ide a high peak powe deposi ion, making he use o in e cep i e moni o s un ea- sible du ing nominal powe ope a ion. To ou bes knowl- edge, nonin e cep i e p o ile measu emen s o deu e on beams a e no epo ed in li e a u e, a leas no in he MeV ene gy ange. Hence, he esul s p esen ed he e may be he i s deu e on beam p o ile measu emen s pe o med using a nonin e cep i e op ical me hod. In his wo k, wo p o o ype luo escence p o ile moni- o s (FPMs), designed and de eloped a CIEMAT [6], we e es ed a he Cen o Nacional de Acele ado es (CNA), Spain [7], whe e he beam p o iling es s we e pe o med wi h a 9 MeV deu e on beam. Expe imen s we e pe o med o mimic he beam pa ame e s o he LIPAc as closely as possible [1]. Al hough he beam cu en was a he low (40 A), o he c i ical pa ame e s, such as ene gy, c oss sec ions, ansi ion b anching a ios, e iciencies, e c., a e he same, wi h he excep ion o acuum p essu e. As he numbe o pho ons p oduced du ing beam-gas in e ac ion is expec ed *[email p o ec ed] Published by he Ame ican Physical Socie y unde he e ms o he C ea i e Commons A ibu ion 3.0 License. Fu he dis i- bu ion o his wo k mus main ain a ibu ion o he au ho (s) and he published a icle’s i le, jou nal ci a ion, and DOI. PHYSICAL REVIEW SPECIAL TOPICS - ACCELERATORS AND BEAMS 15, 072801 (2012) 1098-4402=12=15(7)=072801(9) 072801-1 Ó2012 Ame ican Physical Socie y o inc ease linea ly wi h beam cu en and acuum p essu e [8], an ex apola ion o he numbe o coun s o high cu en scena ios is assumed o be s aigh o wa d. II. FPM PROTOTYPES The p o o ype FPMs a e based on a cus om in ensi ied cha ge injec ion de ice (ICID) came a and a linea pho o- mul iplie ube (PMT) a ay. In he ex , we e e o he o me p o o ype by ICID-FPM and o he la e by PMT-FPM. A b ie desc ip ion o bo h moni o s is p o- ided in he ollowing subsec ions. A. Cus om ICID-FPM The cus om in ensi ied came a employs a adia ion e- sis an cha ge injec ion de ice (CID) came a ins ead o a s anda d CCD. CID came as minimize single e en ans e ine iciencies in in ense adia ion en i onmen s and gua - an ee senso eadings a high doses (i.e., 3 M ad). The CID came a selec ed is a model 8726DX6 by The mo Scien i ic [9]. The CID came a was coupled o an image in ensi ie by P oxi onic [10]. Speci ica ions o he CID and image in- ensi ie a e lis ed in Tables Iand II. The P oxi onic in ensi ie uni has a double s ack mul ichannel pla e (MCP) sandwiched be ween a pho oca hode and a phos- pho sc een. We e e o he comple e sys em as he in en- si ied cha ge injec ion de ice (ICID). The gain o he in ensi ie can be con olled by he MCP ol age om 102 o 106. This ol age is gene a ed by a P oxi onic con ol uni which also p o ides a ga ing pulse. The in eg a ion ime can ollow he pe iod o an ex e nal ansis o - ansis o logic signal o can be p ese o a ixed ime. Sho in eg a ion imes and as synch oniza ion can he e o e be achie ed, see Table II. B. Cus om PMT-FPM The second p o o ype is based on a linea mul ianode PMT a ay coupled o a lens. A 32 channel PMT model H7260, by Hamama su Pho onics [11], was selec ed. The main speci ica ions a e lis ed in Table III. A pu e qua z inpu window was selec ed a he han he s anda d bo osilica ed window in o de o minimize ansmission losses due o i adia ion. The elec onic da a acquisi ion sys em (DAQ) o he PMT a ay is a Pho oniQ model IQSP482 om Ve ilon Co p. (Table IV). The DAQ in e ace acili a es no maliza ion o he PMT channel ou pu s o co ec any channel o channel sensi i i y a ia ions. The gain o he PMT channels can be egula ed by changing he ol age supplied o he me al channel dyn- odes. In his case, a ying he ol age om 500 o 900 V inc eases he ampli ica ion ac o om 2104 o 6106. A e cu en ampli ica ion by he PMT, he DAQ sys em pe o ms cha ge in eg a ion and digi aliza ion, and e u ns he o al in eg a ed cha ge le el (in pico-Coulomb) o each channel. In conjunc ion wi h he PMT, he DAQ sys em pe mi s he cap u e o na ow cha ge pulses wi h single pho on sensi i i y. The PMT ol age, ope a ional modes, and in eg a ion imes can be con igu ed om he in e ace so wa e o he Pho oniQ DAQ sys em. The PMT a ay is moun ed on a mo able boa d placed in a ligh igh housing wi h a s anda d F moun adap o o moun ing an objec i e lens. The mo able boa d allows co ec ocusing wi h di e en lenses. TABLE II. Speci ica ions o he P oxi onic MCP in ensi ie . T ansmission window Qua z Inpu diame e 25 mm Pho oca hode Bialkali (K2SbCs) MCP ype V-s ack Phospho P46 MCP maximum ol age ( ecommended) 1800 V MCP maximum gain 106 Sho es ga e ime 100 ns Maximum igge equency 14 kHz TABLE I. Speci ica ions o he 8726DX6 CID came a. Displayed pixels 726 575 Pixel size 17:3m17:3m SN a io 45 dB signal/ ms Geome ic dis o ion 0% Radia ion ole ance 3 M ad (a leas ) Cable leng h (con ol head) up o 50 m Video ou pu Analog and digi al TABLE III. Speci ica ions o he H7260 mul ianode PMT a ay. T ansmission window Qua z Pho oca hode Bialkali Numbe o channels 32 A ea pe channel 0:87mm Channel pi ch 1 mm Channel c oss- alk 3% TABLE IV. Speci ica ions o he Pho oniQ IQSP482 da a acquisi ion sys em. Numbe o channels 64 Resolu ion 16 bi s Dynamic ange 96 dB Inpu noise cha ge 30 C ms ypical Channel c oss- alk 84 dB ypical Maximum igge a e 120 kHz Minimum e en pai esolu ion 7smaximum J. M. CARMONA e al. Phys. Re . ST Accel. Beams 15, 072801 (2012) 072801-2 III. EXPERIMENTAL SETUP The FPM p o o ypes we e ins alled on he expe imen al line o he CNA cyclo on, jus ups eam om he o a ing wi e scanne (BPM-83 om NEC Co p., ope a ing in seconda y elec on mode) in o de o pe o m a i s c oss-check be ween p o ile s. See Fig. 1. The expe imen- al line is loca ed in a shielded oom, sepa a ed om he cyclo on. Inside and ou side his oom, gamma and neu- on de ec o s a e ins alled o pe sonnel sa e y. A iple magne is ins alled o inal beam shaping. A ixed (15 mm diame e ) collima o is loca ed downs eam om he ip- le . In addi ion, be ween he collima o and he beam p o ile s, wo mo able scin illa o s allow he beam shape o be checked. In addi ion, a beam dump, consis ing o aluminum plus 1 mm o g aphi e, is loca ed a he end o he line. Finally, bo h FPMs we e ins alled in a ho izon al posi ion o iew he e ical p ojec ion o he beam a he same poin , one om le and he o he om igh . A e ins alling he diagnos ics, he ICID-FPM was cali- b a ed by inse ing a calib a ion pa e n (a simple ule ) in he cen e o he beam pipe, wi h low le el, nonuni o m ambien ligh ing. The PMT-FPM was calib a ed agains he ICID-FPM p o o ype due o he lack o a dedica ed in si u calib a ion sys em. A speci ic calib a ion pa e n is being de eloped o he PMT de ice and will be epo ed in u u e wo k. Wi h espec o he op ics, a 25 mm ocal leng h lens (model Megapixel by Edmund Op ics, England) was chosen o he ICID-FPM whe eas a Ca l Zeiss Plana T* 1:4=50 mm lens was selec ed o he PMT-FPM. The a ious pa ame e s ela ed o he calib a ion o he FPMs a e lis ed in Table V, i.e., he ocal leng hs o he lenses, hei numbe , he maximum ield o iew (FOV), he o al scale ac o o he sys em o he yaxis (y), he calib a ion ac o o each p o o ype, and he dep h o ocus o ICID. The calib a ion ac o ag ees well wi h calib a ions pe o med wi h a pencil lamp on an op ical labo a o y es - bench he eby p o iding a c oss-check. Fo beam p o ile measu emen s, he dep h o ocus should co e a leas he beam diame e in o de o minimize b oadening e ec s. I needed, he dep h o ocus can be inc eased by s opping down he numbe a he expense o signal. The p esen comp omise be ween numbe and signal s eng h seems o be adequa e o he cu en ange o beam sizes. As we we e in e es ed in ob aining good s a is ics, we did no employ a il e o hese measu emen s. Hence, he de ec o s collec ed pho ons ac oss he whole isible spec- um. Thus, he con ibu ion o each ansi ion in he inal p o ile will be a con olu ion o he spec al line emission in ensi y wi h he spec al e iciency o each de ec o . The maximum spec al esponse o bo h de ec o s lies be ween 370–460 nm [10,11]. The mos in ense ni ogen line an- si ions lie in he same spec al egion (e.g., 391.4 and 427.3 nm) [2,5], hence he sys em is conside ed o be op imized. IV. SIMULATING HIGH CURRENT SCENARIOS The emissi i y , see Eq. (1), due o he in e ac ion o beam ions wi h esidual gas can be exp essed as he num- be o pho ons emi ed pe second pe pa h leng h (dpa h). I TABLE V. Op ical pa ame e s o ICID-FPM and PMT-FPM. Pa ame e Uni s ICID PMT Focal leng h [mm] 25 50 /numbe 2.8 2.8 FOV [mm] 181 250 y0.55 0.79 Calib a ion [mm/(pixel, channel)] 0.315 7.8 Dep h o ield [mm] 30  FIG. 1. Layou o he expe imen al line and diagnos ics o he CNA cyclo on. MEASUREMENTS OF NONINTERCEPTIVE ... Phys. Re . ST Accel. Beams 15, 072801 (2012) 072801-3 also depends on he beam cu en , Ibeam, he numbe o esidual gas pa icles wi hin he beam-gas in e ac ion olume (p essu e Pgas), and he o al c oss sec ion, , o pho on ansi ions (exci a ion plus deexci a ion o he gas pa icles). The numbe o de ec ed pho ons [Eq. (2)] and, mo e speci ically, he numbe o coun s, N, collec ed by a de ec o depends on he emissi i y, , he solid angle, , he in eg a ion ime, T, and he sys em e iciency, sis : /PgasIbeamdpa h (1) N/Tsis :(2) In o de o simula e LIPAc condi ions, i.e., same c oss sec ions and b anching a ios, he es s a e pe o med wi h 9 MeV deu e ons. The main pa ame e s a CNA ma ch hose o LIPAc, wi h he excep ion o he lowe cu en ; bu in iew o he abo e, he low cu en s can be compen- sa ed o by inc easing he gas p essu e. Indeed, he emis- si i y can be inc eased by changing he numbe o pa icles in ol ed in he in e ac ion, i.e., by inc easing he beam cu en o he gas p essu e [Eqs. (1) and (2)]. Thus, he esul s ob ained in hese expe imen s can be ex apola ed o highe cu en deu e on beams in a s aigh o wa d manne . In o de o check ha wide beam p o iles a e accessible o his echnique, i was p e e able o use a beam wi h la ge ans e se size in hese ini ial expe imen s. Usually, he beam is widened jus ups eam om he beam s op o educe he deposi ion powe densi y. A he same ene gy and beam cu en , wide p o iles a e mo e di icul o mea- su e because o he smalle pho on densi y (and a poo e signal o noise a io). V. MEASUREMENTS WITH DEUTERONS Be o e p oceeding o he analysis, in his sec ion we p esen he i s uns and commen on each p o ile p o o- ype, including a p o ile c oss-check wi h a adi ional in e cep i e p o ile (i.e. a wi e scanne ). A. PMT-FPM i s uns F om he i s es s, i was e iden ha he PMT-FPM p o o ype was capable o measu ing p o iles wi h lowe beam cu en s han he ICID-FPM p o o ype. Figu e 2(a) shows a beam p o ile eco ded by he o me using a 9 MeV, 400 nA deu e on beam. Fo his, he p essu e in he diagnos ic chambe was 3:6104mba when using ni ogen (N2). Unde hese condi ions, a clea beam p o ile was ob ained. The PMT ol age was se a i s maximum alue while he o al in eg a ion ime was 100 ms. The beam wid h ðyÞ, ob ained om a Gaussian i o he da a, was 10:20:4mm. This e o is he i e o , gi ing he 1-con idence bound o he beam wid h. To demons a e he s anda d de ia ion o he beam wid h measu emen s unde hese condi ions, 20 samples wi h 100 ms o in eg a ion ime a e plo ed in Fig. 2(b). Again, he beam wid h ðyÞis de e mined by a Gaussian i o each sample. The mean o he beam wid hs is 10.17 mm whe eas he s anda d de ia ion o he beam wid hs [SDðÞ], is 0.49 mm, esul ing in 10:20:5mm. Be e pho on s a is ics (highe signal le els) educes he [SDðÞ] imp o ing he p ecision o he measu emen s. As no ed, he p essu e le el du ing hese expe imen s (a ound 104mba ) was chosen o compensa e o he low beam cu en (0:4–40 A) and hence o simula e highe beam cu en scena ios (i.e., 125 mA o LIPAc). Because o he linea ela ion be ween beam cu en and pho on s a is ics (see Sec. VI A), i is conside ed ha he p essu e le els ypically ound in LINACs (106–108mba ) will su ice o ope a ion o FPM p o ile s. B. ICID-FPM i s uns Figu e 3shows a pic u e o he acuum chambe , e- co ded by he ICID-FPM wi hou he beam, using ex e nal illumina ion om a nea by iewpo . Two ci cles delimi bo h iewpo s, he ICID-FPM iewpo (la ge ci cle) and 5 10 15 20 25 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 Channel In ens y (pC) Gaussian i Da a 0 5 10 15 20 5 6 7 8 9 10 11 12 13 14 15 Sample numbe σ (mm) Da a Mean FIG. 2. Fi s p o ile acqui ed (a) wi h he PMT-FPM p o o- ype o a Dþcu en o 400 nA and a N2p essu e o 3:6104mba . 20 consecu i e beam p o ile samples a e an- alyzed (b) o check he s anda d de ia ion o he beam wid hs [ðmmÞ] in such condi ions. J. M. CARMONA e al. Phys. Re . ST Accel. Beams 15, 072801 (2012) 072801-4 he PMT-FPM iewpo (small ci cle). Re lec ions o he beam pipe walls a e isible. Pixels ou side he smalle ci cle can be a ec ed by wall e lec ions du ing p o ile ope a ion. Hence, he a ea wi hin he small ci cle is aken as he egion o in e es (ROI) whe e he con ibu ion o ligh e lec ions on he beam p o ile is educed. A black- ened chambe will u he minimize ligh e lec ions, pe - mi ing a la ge ROI (i.e., he la ge ci cle). Two beam images [Figs. 4(a) and 4(c)] and hei co e- sponding ans e se beam p o iles [Figs. 4(b) and 4(d)] a e shown o di e en expe imen al condi ions (and de ec o se up). He e, he small ci cle has been aken as he ROI o he ans e se p o ile. The beam is clea ly isible in bo h cases, and a i o each p o ile gi es a beam wid h o ¼7:1mm. The gain (MCP ol age) o he ICID-FPM p o o ype has o be adjus ed o he di e en expe imen s o ob ain he bes possible image. As beam cu en inc eases, a lowe ampli ica ion can be used, esul ing in a p o ile wi h e- duced noise. In con as , a high MCP ol age can easily sa u a e he de ec o a high beam cu en s. C. Beam p o ile c oss-checking P elimina y c oss-checks be ween he FPM p o o ypes and a wi e scanne we e pe o med (see Fig. 5). The beam condi ions o he se ies Figs. 5(a)–5(c) we e a beam cu en o 15 A, a ni ogen p essu e o 7104mba , and a wide beam. The ol age applied o he MCPs o he 100 150 200 250 300 350 400 450 500 0.8 0.9 1 1.1 1.2 1.3 1.4 x 104 Pixels In ensi y [A b. uni s] da a i ed cu e 100 150 200 250 300 350 400 450 500 1.4 1.5 1.6 1.7 1.8 1.9 2 2.1 2.2 2.3 2.4 2.5 x 104 Pixels In ensi y [A b. uni s] da a i ed cu e FIG. 4. Beam images (le ) and co esponding p o iles ( igh ) wi hou ea men . Expe imen al condi ions a e (a) beam in ensi y 2:5A, p essu e 8:7104mba , MCP ol age 1700 V, (c) beam in ensi y 20 A, p essu e 7:4104mba , MCP ol age 1600 V. Beam wid hs a e ¼7:10:6mm o (b) and ¼7:10:3mm o (d). Viewpo FIG. 3. Image o he acuum chambe ob ained by he ICID- FPM. The la ge ci cle delimi s he ICID-FPM iewpo whe eas he small ci cle delimi s he PMT-FPM iewpo . Wall e lec- ions a e seen clea ly. MEASUREMENTS OF NONINTERCEPTIVE ... Phys. Re . ST Accel. Beams 15, 072801 (2012) 072801-5 ICID came a was 1580 V. In eg a ion imes o he ICID- FPM and PMT-FPM we e 20 and 5 ms, espec i ely. The beam condi ions o he bo om se ies [Figs. 5(d)–5( )] we e 10 A,8:7104mba , and a smalle beam. The ol age applied o he MCPs o he ICID came a was 1700 V. In eg a ion imes o he ICID-FPM and PMT-FPM we e 20 and 100 ms, espec i ely. Beam p o- iles ob ained wi h he wi e scanne [Figs. 5(c) and 5( )] a e also shown o compa ison. The beam wid hs ob ained wi h each ype o p o ile a e shown in he cap ion. The highe noise ound in Fig. 5(d), as compa ed o Fig. 5(a),is due o he highe ampli ica ion ac o applied o he MCP o compensa e he lowe beam cu en . The beam wid hs o he a ious p o iles shown in Fig. 5a e in easonable good ag eemen . Mo eo e , he eco ded p o ile shapes a e simila , wi h only a sligh de ia ion om he Gaussian cu e on he igh in he op se ies example. D. Ex apola ions o LIPAc Using he p o ile o Fig. 2, he pulse leng h equi ed o measu ing a simila p o ile in LIPAc (9 MeV, 125 mA) can be es ima ed. I he p oduc be ween he beam cu en , he p essu e, and he acquisi ion ime (o beam pulse) is as- sumed equal (see Sec. IV), hen i should be possible o ob ain a p o ile wi h simila quali y. Fo he pa ame e s o Fig. 2, we ob ain 4104mA  3:6104mba 100 ms ¼1:44 105½mA mba ms. Compa ing his alue o he LIPAc case, i.e. 125 mA  106mba  pulse, i will be possible o measu e a beam wi h a single pulse leng h ( pulse)o 115 s, (0.01% o du y cycle). Fo hese calcula ions, a p essu e o 106mba has been assumed, al hough any p essu e could be used (e.g. o 107mba , he co esponding pulse leng h would be 1:2ms). Simila ly, o moni o s loca ed a he end o he LIPAc line (a a p essu e o 105mba unde nominal con- di ions), he co esponding pulse leng h would be 11:5s. The same ex apola ion can be applied o Figs. 5(a) and 5(b). Again, i he p oduc o beam cu en , p es- su e, and in eg a ion ime is assumed equal, a e e ence alue o in eg a ion ime needed o eplica e simila p o- iles in LIPAc can be es ima ed. Fo he ICID-FPM p o o- ype, a 1.7 ms beam pulse (o in eg a ion ime) will be equi ed, whe eas a 420 spulse will be equi ed o he PMT wi h he same de ec o se ings. The e e ence p es- su e used in hese es ima ions is 106mba . This assump ion o linea i y o cu en and p essu e is analyzed in he nex sec ion. VI. CURRENT AND PRESSURE SCANS Two scans we e pe o med in o de o check he line- a i y o he ela ion be ween he p o ile ampli ude, he 150200250300350400450500550 0 1000 2000 3000 4000 5000 6000 7000 8000 Pixels In ensi y [A b. uni s] Da a Gaussian i 510 15 20 400 600 800 1000 1200 1400 1600 1800 2000 2200 Channels In ensi y (pC) Da a Gaussian i 0.03 0.035 0.04 0.045 0.05 0.055 0.06 0.065 0.01 0.015 0.02 0.025 0.03 0.035 Time (s) In ensi y [a b. uni s] Da a Gaussian i 200250300350400450 1000 2000 3000 4000 5000 6000 7000 8000 9000 Pixels In ensi y [A b. Uni s] Da a Gaussian i 510 15 20 25 0.5 1 1.5 2 2.5 3x 10 4 Channels In ensi y (pC) Da a Gaussian i 0.005 0.01 0.015 0.02 0.025 0.03 0.5 1 1.5 2 2.5 3 Time (s) In ensi y [A b. uni s] Da a Gaussian i FIG. 5. T ans e se beam p o iles o a Dþcu en o 15 A( op) and 10 A(bo om) eco ded by he ICID-FPM p o o ype (a),(d), he PMT-FPM p o o ype (b),(e) and he wi e scanne (c),( ). A Gaussian cu e is i ed o he da a. The ans e se beam sizes [ð msÞ] ob ained om he i s a e ¼10:30:1mm (a), ¼10:50:5mm (b), and ¼10:40 0:01 mm (c) o he op, and ¼6:80:2mm(d), ¼7:40:4mm(e), and ¼7:61 0:01 mm ( ) o he bo om. J. M. CARMONA e al. Phys. Re . ST Accel. Beams 15, 072801 (2012) 072801-6 beam cu en , and he gas p essu e. These scans a e also used o s udy he dependence o he p o ile beam wid h on beam cu en and acuum p essu e o 9 MeV deu e ons. The eliabili y o he luo escence echnique is discussed below. The scans we e sys ema ic, i.e., changing only one pa ame e a a ime du ing he se s o measu emen s. The expe imen al da a, see Figs. 6and 7, we e eco ded using he PMT-FPM p o o ype as he ampli ica ion ac o could be kep cons an du ing bo h scans [independen ly o he backg ound adia ion (BR) le el] wi hou pushing he de ec o in o sa u a ion. Wi h he ICID-FPM, i was neces- sa y o a y he ampli ica ion ac o (MCP ol age) due o noise and/o image sa u a ion. A. Beam cu en scan The ni ogen p essu e inside he diagnos ic chambe was held a 2:3104mba du ing he cu en scan. This alue gua an eed good p o ile measu emen s a he lowes cu en se ing o he scan (i.e., 400 nA). Fo he scan he deu e on beam cu en was a ied be ween 400 nA and 32 A. In all cases, he o al in eg a ion ime o he PMT-FPM was 100 ms, while he ol age was se o maximum gain. Beam p o iles a e shown in Fig. 6(a) as a unc ion o beam cu en . The e olu ion o he in eg a ed p o ile in ensi y (sum o he in ensi y measu ed by each PMT channel minus backg ound signal pe channel) and he beam wid h, ðyÞ, e sus he deu e on cu en a e shown in Figs. 6(b) and 6(c), espec i ely, whe e he expec ed linea ela ion be ween he p o ile in ensi y and he beam cu en is con i med [see Fig. 6(b)]. A linea i was pe - o med o he da a o highligh he endency and a slope o 2:74 103pC=Awas ound. In addi ion, Fig. 6(c) shows ha he beam wid h (as de e mined by a Gaussian i ) ends o emain cons an when inc easing he beam cu en om 0.4 o 32 A. The mean alue is 8.3 mm wi h a s anda d de ia ion o 0.9 mm (8:30:9mm). The a ia ion o he beam wid h is la ge a low beam cu en s as a consequence o lowe signal s eng h. The s anda d de ia ion d ops o 0.4 mm o beam cu en s exceeding 2:5A. 32 0 10 20 30 0 0.5 1 1.5 2 2.5 3 x 104 Beam Cu en (µA) PMT Channel In ensi y (pC) 0 5 10 15 20 25 30 35 0 1 2 3 4 5 6 7 8 9 10 x 104 Beam Cu en (µA) P o ile In eg a ed In ensi y (pC) Da a Linea i 0 5 10 15 20 25 30 35 0 5 10 15 Beam Cu en (µA) σ (mm) Da a Mean FIG. 6. Beam p o iles e sus beam cu en du ing a sys ema ic scan (a). Fo each p o ile, he in eg a ed p o ile in ensi y e sus he beam cu en is shown in (b) oge he wi h a linea i (y¼2737:6½pC=AIbeam 2107:7½pC). The measu ed beam wid h  e sus beam cu en is shown in (c). The mean wid h o hese da a is 8.3 mm. 0 2 4 0 10 20 30 0 1 2 3 4 5 6 x 104 P essu e ×10−4 (mba ) PMT Channel In ensi y (pC) 123456789 1 2 3 4 5 6 7 8 9x 104 P essu e ×10−4 (mba ) P o ile In eg a ed In ensi y (pC) Da a Linea i 123456789 0 5 10 15 P essu e × 10−4 (mba ) σ (mm) Da a Mean FIG. 7. Beam p o iles e sus N2p essu e du ing a sys ema ic scan (a). Fo each p o ile, he in eg a ed p o ile in ensi y e sus p essu e is shown in (b) oge he wi h a linea i (y¼8:2107½pC=mba Pgas þ6963:1½pC). The measu ed beam wid h  du ing he p essu e scan is shown in (c). The mean size o hese da a is 7.4 mm MEASUREMENTS OF NONINTERCEPTIVE ... Phys. Re . ST Accel. Beams 15, 072801 (2012) 072801-7 I should be no ed ha he beam dump was no shielded. Hence, he highe he deu e on beam cu en , he g ea e he adia ion backg ound, BR, esul ing in an inc eased backg ound signal a he de ec o s, BS, du ing he measu emen s. This will be discussed in he nex sec ion. B. Gas p essu e scan The beam cu en was ixed a 10 Adu ing he p es- su e scan. The o al in eg a ion ime was 100 ms and he ol age was again se o maximum gain, while he p es- su e was aised om 2 o 8104mba . Al hough his moni o can be used a lowe p essu e se ings (depending on he beam cu en and in eg a ion ime), we a e in e - es ed in high p essu e se ings in iew o ou objec i e o simula ing high beam cu en scena ios using low beam cu en s. Figu e 7shows beam p o iles [Fig. 7(a)], in eg a ed p o ile in ensi ies [Fig. 7(c)], and ans e se beam sizes ðmmÞ[Fig. 7(c)] e sus N2p essu e. A linea ela ion be ween he p o ile in ensi y and he p essu e was ound [see Fig. 7(b)]. Again, a linea i was pe o med o he da a o highligh he endency and a slope o 8:2 107pC=mba was ob ained. In addi ion, he beam wid h ðmmÞ ends o emain cons an when inc easing he N2 p essu e [see Fig. 7(c)]. The mean o hese da a is 7.38 mm, wi h a s anda d de ia ion o 0.32 mm (7:40:3mm). C. Xenon as esidual gas The beam cu en scan was epea ed using xenon a he han ni ogen as he dominan gas. Fo his, he xenon p essu e inside he beam chambe was held a 8:6 104mba and he beam cu en ange was smalle han o ni ogen, i.e., be ween 15 and 35 A. A compa ison o he in eg a ed p o ile in ensi ies and BSbe ween he N2and he Xe expe imen s is shown in Fig. 8. As he acuum p essu es we e di e en in he expe imen s, only quali a- i e compa isons can be made. The in eg a ed p o ile in ensi ies [Fig. 8(a)] and BS [Fig. 8(b)] inc ease linea ly wi h beam cu en o bo h gases. The p o ile in ensi ies eco ded using N2[see Fig. 8(a)] a e 2.5 imes highe han hose eco ded using Xe, e en when he N2p essu e was 3.6 imes lowe (2:3104mba o N2 e sus 8:2104mba o Xe). Hence, a highe pho on yield is ound o ni ogen when compa ed wi h xenon, a leas in he spec al ange o maximum de ec o e iciency (maximum quan um e i- ciency occu s a 400 nm and d ops abo e 460 nm, alling o ze o a 660 nm). This is consis en wi h ea lie wo k compa ing N2and Xe, using di e en beams [5,12]. VII. BACKGROUND SIGNAL DURING MEASUREMENT Figu e 8(a) shows ha in eg a ed p o ile in ensi ies a e 150% highe wi h N2 han wi h Xe, al hough he BSle els be ween N2and Xe a e simila (a 30% highe o N2). The e o s o BSle els a e ypically 10%–15%. Hence, @BS=@I, he a ia ion o BS e sus beam cu en , is close o cons an o bo h gases. I he BSis due o wall e lec ions, i should be p opo - ional o he emissi i y [Eq. (1)]. In ha case, @BS=@I should be di e en o N2o Xe because o di e en emissi i ies. On he o he hand, adia ion inc eases he BSand he noise in de ec o s [13], and his seems o be he case he e. The majo con ibu o o he BSis he e o e p obably he adia ion backg ound, a he han e lec ed o sca e ed pho ons. The adia ion dose a e is cons an o a ixed beam cu en , independen om he gas used (in he p esen p essu e ange). This mechanism can explain he simila BSle els a di e en pho on yields. Figu e 8(c) shows he gamma and neu on adia ion doses e sus he deu e on beam cu en , eco ded du ing p o ile measu e- men s. Bo h he adia ion dose a e and he BSinc ease linea ly wi h he beam cu en . Re lec ions o he beam ube walls and hei e ec on BSa e conside ed o be less han he con ibu ion due o 0 5 10 15 20 25 30 35 40 0 1 2 3 4 5 6 7 8 9 10 x 10 4 Beam cu en (µA) P o ile In eg a ed In ensi y (pC) 0 5 10 15 20 25 30 35 40 0 2000 4000 6000 8000 10000 12000 Beam cu en (µA) Backg ound Signal (pC) 0 5 10 15 20 25 30 35 0 10 20 30 40 50 60 70 80 90 100 Beam cu en ( µ A) Rad Dose (mS /h) FIG. 8. In eg a ed p o ile in ensi ies (a) and BS(b) using ni ogen (ci cles) and xenon (squa es) plo ed e sus beam cu en . Gamma ( iangles) and neu on (diamonds) adia ion doses egis e ed du ing he cu en scan a e shown in (c). Linea i s o he da a a e also shown. J. M. CARMONA e al. Phys. Re . ST Accel. Beams 15, 072801 (2012) 072801-8 adia ion bu no comple ely negligible. This migh explain he sligh ly lowe alues o BS o xenon. A beam pipe wi h a blackened inside su ace will educe he con ibu ion o e lec ed pho ons, also p e en ing p o ile de o ma ions. Beam p o ile s a e usually loca ed ou side o he shielded a ge a ea. Fo his wo k, he beam p o ile s and he beam dump we e loca ed in he same aul (Fig. 1) and we e subjec ed o a signi ican adia ion backg ound du ing he measu emen s [see Fig. 8(c)]. Al hough FPMs we e capable o measu ing wi h his gamma backg ound, shield- ing he FPMs will imp o e he measu emen s and he ope a ional li e o he de ec o in in ense adia ion en i onmen s. VIII. FUTURE WORK A spec al il e could be placed in on o he lens o selec a speci ic line ansi ion, a he cos o educing pho on s a is ics. The il e ing op ion adds high lexibili y o FPMs by p o iding a way o deal wi h possible p o ile dis o ions. In he case o beams wi h a high space cha ge, ansi ions wi h sho li e imes can be selec ed o educe he pa icle d i e ec du ing he decay ime. A il e wheel will be de eloped and ins alled in on o he de ec o lens o imp o e he u u e pe o mance o he p o ile s. As his is a wo k in p og ess, some imp o emen s s ill need o be made be o e ins alla ion a LIPAc. New es s wi h blackened walls o a oid e lec ions o he beam pipe walls will be pe o med. The con ibu ion o he adia ion backg ound (gammas-neu ons) e sus e lec ed pho ons will be ho oughly analyzed in he nea u u e. Fu u e wo k includes he design o a dedica ed calib a ion pa e n, a mi o in he op ical pa h o p o ile s close o a ge a eas ( o allow be e shielding), o he in eg a ion o elec onics in o he EPICS [14] based local con ol sys em. IX. CONCLUSIONS Two p o o ypes o nonin e cep i e p o ile moni o s based on gas luo escence, ha e been designed o he LIPAc accele a o . Fi s in-beam es s ha e been ca ied ou success ully wi h a deu e on beam a he CNA cyclo- on. Measu emen s we e pe o med unde a ying expe i- men al condi ions and he obse ed endencies ha e been highligh ed. Sys ema ic scans o he beam cu en and gas p essu e show he consis ency and eliabili y o his beam p o ile echnique. The gamma and neu on backg ound con ibu ion o he measu emen BSle el o he de ec o s is subjec o u he s udy. As his is a wo k in p og ess, some imp o emen s mus s ill be made in he nea u u e, such as implemen ing a blackened acuum chambe , a il e wheel, and a dedica ed calib a ion pa e n. ACKNOWLEDGMENTS This wo k has been pa ially unded by he Spanish Minis e io de Ciencia e Inno acio ´n P ojec No. ENE2009-11230/FTN, Diagnos ics and Techniques o u u e pa icles Accele a o s NETwo k DITANET p ojec , PITN-GA-2008-215080 and he p ojec FPA2009-08848 om Spanish Minis e io de Ciencia e Inno acio ´n, and he excellence p ojec P07-FQM-02894 suppo ed by Jun a de Andalucı ´a. [1] P. Ga in, in P oceedings o he 11 h Eu opean Pa icle Accele a o Con e ence, Genoa, 2008, edi ed by C. Bisca i and C. Pe i -Jean-Genaz (EPS-AG, Genoa, I aly, 2008), TUZG01 [h p://accelcon .web.ce n.ch/AccelCon / e08/pape s/ uzg01.pd ]. [2] M. Plum, E. B a in, J. Bosse , and R. Macca e i, Nucl. Ins um. Me hods Phys. Res., Sec . A 492,74 (2002). [3] A. Va iola, R. Jung, and G. Fe ioli, Phys. Re . ST Accel. Beams 10, 122801 (2007). [4] T. Tsang, S. Bella ia, R. Connolly, D. Gassne , Y. Makdisi, T. Russo, P. Thiebe ge , D. T boje ic, and A. Zelenski, Re . Sci. Ins um. 79, 105103 (2008). [5] F. Becke , C. And e, P. Fo ck, R. Hasei l, A. Hug, B. Walasek-Hoehme, F. Bieniosek, and D. H. H. Ho mann, in he 9 h Eu opean Wo kshop on Beam Diagnos ics and Ins umen a ion o Pa icle Accele a o s, edi ed by Jan Ch in, Michaela Ma x, Volke R. W. Schaa, and Volke Schlo (2009), TUPB02 [h p://dipac09.web.psi.ch/ P oceedings/pape s/ upb02.pd ]. [6] Cen o de In es igaciones Ene ge ´ icas, Medioambien ales y Tecno ´logicas (CIEMAT) [h p://www.ciema .es]. [7] Cen o Nacional de Acele ado es (CNA) [h p://in a.sa .us.es:8080/cna/index.php/en]. [8] F. Becke , C. And e, P. Fo ck, and D. H. H. Ho mann, in he 8 h Eu opean Wo kshop on Beam Diagnos ics and Ins umen a ion o Pa icle Accele a o s, edi ed by I an And ian and Volke R. W. Schaa (2007), MOO3A02 [h p://accelcon .web.ce n.ch/AccelCon /d07/pape s/ moo3a02.pd ]. [9] The mo Scien i ic Inc. [h p://www. he moscien i ic.com/ wps/po al/ s/HOME]. [10] P oxi onic De ec o Sys ems GmbH [h p://www .p oxi onic.com/]. [11] Hamama su Pho onics [h p://www.hamama su.com/]. [12] C. Bohme, T. Weis, V. Kame dzhie , J. Die ich, and J. L. Con adie, in he 9 h Eu opean Wo kshop on Beam Diagnos ics and Ins umen a ion o Pa icle Accele a o s, edi ed by Jan Ch in, Michaela Ma x, Volke R. W. Schaa, and Volke Schlo (2009), TUPB10 [h p:// accelcon .web.ce n.ch/accelcon /d09/pape s/ upb10 .pd ]. [13] S. Hu chins, M. Facchini, and E. Tsoulou, in he 7 h Eu opean Wo kshop on Beam Diagnos ics and Ins umen a ion o Pa icle Accele a o s, edi ed by Volke R. W. Schaa (2005), CTWA02 [h p://accelcon .web.ce n.ch/AccelCon /d05/PAPERS/CTWA02.PDF]. [14] Expe imen al Physics and Indus ial Con ol Sys em (EPICS) [h p://www.aps.anl.go /epics/]. MEASUREMENTS OF NONINTERCEPTIVE ... Phys. Re . ST Accel. Beams 15, 072801 (2012) 072801-9