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.
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MEASUREMENTS OF NONINTERCEPTIVE ... Phys. Re . ST Accel. Beams 15, 072801 (2012)
072801-9