Nuclea Ins . and Me hods in Physics Resea ch, A 1045 (2023) 167652
Con en s lis s a ailable a ScienceDi ec
Nuclea Ins . and Me hods in Physics Resea ch, A
jou nal homepage: www.else ie .com/loca e/nima
Imp o ing coun a e capabili y o iming RPCs by inc easing he de ec o
wo king empe a u e
A. Blanco a,∗, P. Fon e a,b, L. Lopesa, J. Sa ai a a
aLabo a o y o Ins umen a ion and Expe imen al Pa icles Physics, Coimb a, Po ugal
bCoimb a Poly echnic - ISEC, Coimb a, Po ugal
ARTICLE INFO
Keywo ds:
Gaseous de ec o s
Timing
TOF
RPC
ABSTRACT
This communica ion desc ibes es beam esul s, ocusing on de ec ion e iciency and iming p ecision, o
common loa glass iming Resis i e Pla e Chambe s ( RPCs) exposed o a 2.7 GeV p o on beam and ope a ed
a abo e ambien empe a u e in o de o inc ease he coun a e capabili y o he chambe s, by exploi ing he
educ ion in he esis i i y o he glass elec odes. Resul s sugges ha he coun a e capabili y can be ex ended
a leas up o 1500 Hz∕cm2when he de ec o is ope a ed a 40.6◦C wi hou no iceable loss o e iciency o
iming p ecision deg ada ion wi h alues a ound 90% and 100 ps, espec i ely, o his speci ic iming RPC
a angemen .
1. In oduc ion
RPC ha e adi ionally been used wi h ela i ely lowe pa icle
lux (≪kHz∕cm2) due o he inhe en limi a ion o he coun ing
a e imposed by he commonly used loa glass elec ode esis i i y.
Since RPCs a e one o he main la ge-a ea iming de ec o s, ex ension
o i s coun ing a e capabili y is o g ea in e es o u u e High
Ene gy Pa icle (HEP) expe imen s, whe e he luminosi y is expec ed
o inc ease conside ably.
A emp s ha e al eady been made o inc ease he coun a e capabil-
i y by using ma e ials wi h lowe elec ical esis i i y compa ed o he
commonly used loa glass, such as ce amics [1,2], special glasses [3]
o some echnical plas ics [4]. As a esul , he ope a ion o small a ea
de ec o s was success ully achie ed, bu he implemen a ion o he
medium/la ge a ea de ec o s ailed due o he lack o homogenei y o
he ma e ials, which p esen lowe elec ical esis i i y pa hs, esul ing
in an uns able beha io o he de ec o . Ano he possibili y, s ill e y
li le explo ed, is o dec ease he esis i i y o s anda d loa glass by
inc easing he ope a ional empe a u e o he de ec o s, p o iding a
en- old dec ease in esis i i y e e y 25 ◦C [5].
This communica ion desc ibes es beam esul , ocusing on de-
ec ion e iciency and iming p ecision, o common loa glass RPCs
exposed o inciden pa icle luxes up o 1500 Hz∕cm2and ope a ed up
o 40.6◦C.
2. Expe imen al se up
The expe imen al layou consis o ou indi idually shielded s ip-
like RPC s acked one on op o he o he , see Figs. 1a and 1b. Each
∗Co esponding au ho .
E-mail add ess: [email p o ec ed] (A. Blanco).
indi idual chambe consis s o h ee aluminum (2 mm hickness) and
wo glass (soda-lime) elec odes wi h a leng h o 750 mm and wo di -
e en wid hs 22 mm (𝑅𝑃 𝐶1and 𝑅𝑃 𝐶4) and 44 mm (𝑅𝑃 𝐶2and 𝑅𝑃 𝐶3).
Two o he chambe s (𝑅𝑃 𝐶3and 𝑅𝑃 𝐶4) a e equipped wi h 1 mm glass,
(bulk esis i i y o ≈ 4 × 1012 Ωcm a 25 ◦C) while he o he s (𝑅𝑃 𝐶2
and 𝑅𝑃 𝐶1) a e equipped wi h 2 mm hick glass (bulk esis i i y o
≈ 1 × 1013 Ωcm a 25 ◦C). All o he elec odes ha e ounded edges and
he glass exceeds he aluminum in size by 1 mm (in bo h dimensions)
o p e en discha ges, see Figs. 1b and 1c. The gap is de ined by PEEK
(Polye he e he ke one) mono- ilamen s o 0.270 mm diame e , spaced
app oxima ely by 100 mm along he chambe . The s ack is housed inside
indi idual aluminum ubes (shielding) and comp essed by sp ings on
op o each mono- ilamen ha apply a con olled o ce h ough a PVC
(Poly inyl chlo ide) pla e ha dis ibu es he o ce.
High- ol age (HV) close o 6kV is applied o he cen al aluminum
elec ode ia 1MΩ esis o s and high ol age cables, while he ou e
elec odes a e g ounded and he glass elec odes a e kep elec ically
loa ing. Insula ion o he shielding ube walls is assu ed by a iple-
laye KAPTON™adhesi e lamina e. An end-shield made o aluminum
oil is glued o bo h ends o he aluminum ube o p oduce a ully
shielded elemen . The signals a e collec ed, a bo h ends o each
chambe , by coaxial cables h ough 2nF 𝐻𝑉 coupling capaci o s and
ex ac ed om he gas box h ough he on panel ia RF MMCX
connec o s.
The gas box is equipped wi h empe a u e senso s and a hea ing
elemen , capable o inc ease he wo king empe a u e homogeneously
in he inne chambe s up o a leas 40.6◦C. A se o as plas ic
scin illa o s de ine a beam line ( elescope). The elescope is composed
h ps://doi.o g/10.1016/j.nima.2022.167652
Recei ed 28 June 2022; Recei ed in e ised o m 6 Oc obe 2022; Accep ed 11 Oc obe 2022
A ailable online 23 Oc obe 2022
0168-9002/©2022 Else ie B.V. All igh s ese ed.
i An upda e o his a icle is included a he end
A. Blanco, P. Fon e, L. Lopes e al. Nuclea Ins . and Me hods in Physics Resea ch, A 1045 (2023) 167652
Fig. 1. (a) In e nal a angemen o he RPC. (b) C oss sec ion o he ou chambe s a angemen and (c) close-up pho og aph o one o he 22 mm wide chambe , wi h: 1—Al
elec odes, 2—glass elec odes, 3—PVC p essu e pla e and 4—2 mm hick aluminum shielding ube. (d) Pano amic iew o he se up in he beam line, showing he RPC gas box,
su ounded by he hea ing wi e, and he las scin illa o o he elescope. (e) C oss sec ion o he scin illa o and RPC in he beam line.
o h ee pa allelepipeds 80 × 30 × 20 mm3scin illa o s (Bic on BC420),
SC1, SC2and SC3( he i s one, SC1, wi h he la ges dimension pa allel
o he g ound while in he o he wo, SC2and SC3, his dimension is
pe pendicula o he g ound, see Fig. 1e. Each o he scin illa o s is ead
by wo as PMTs (Hamama su H6533) on each side o 20 × 30 mm2.
The 20 mm side aces he beam passing h ough 30 mm scin illa o o
maximum iming p ecision.
Bo h RPC and he PMTs signals a e eed o as F on End Elec on-
ics (FEE) [6] ( o PMT eadou he ampli ica ion s age was emo ed)
capable o measu ing ime and cha ge in a single channel. The esul ing
signals a e ead ou by he TDC-Readou -Boa d (TRB) [7] equipped
wi h 128 mul i-hi TDC (TDC-in-FPGA echnology) channels wi h a ime
p ecision be e han 20 ps.
The chambe s we e ope a ed in open gas loop a a lux a e o
a ound 50 cm3/min wi h a mix u e o 97% C2H2F4and 3% SF6, exposed
o 2.7 GeV p o on beam wi h a 2D-Gaussian p o ile wi h a FWHM
o 20 mm, luxes up o 1500 Hz/cm2and wo king empe a u es up
o 40.6◦C. Since he gain o a RPC depends on he p essu e and
empe a u e o he gas, he applied 𝐻𝑉 is modula ed as a unc ion o
hese wo a iables acco ding o [8] in o de o keep he gain cons an .
3. Me hods
The es ocused on ob aining he iming p ecisions, 𝜎𝑅𝑃 𝐶𝑖, and
e iciency, 𝜖𝑖, o each indi idual RPC 𝑖= 1...4, as a unc ion o he
pa icle lux, om a ew Hz∕cm2up o 1500 Hz∕cm2(measu ed using
he scin illa o elescope) o di e en empe a u es, om 21 ◦C up o
40.6◦C. Fo each pa icle de ec ed in he RPC 𝑖, he ollowing a iables
a e compu ed: ime as 𝑇𝑖= (𝑇𝑖𝑙 +𝑇𝑖𝑟)∕2, whe e 𝑇𝑖𝑙 and 𝑇𝑖𝑟 a e he le
and igh imes and cha ge as 𝑄𝑖= (𝑄𝑖𝑙 +𝑄𝑖𝑟)∕2, wi h 𝑄𝑖𝑙 and 𝑄𝑖𝑟 he
le and igh cha ges. Any ime di e ences in ol ing 𝑇𝑖a e co ec ed
as a unc ion o 𝑄𝑖using a slewing co ec ion. Simila p ocedu e is
ollowed o he scin illa o signals. RPC iming p ecision, 𝜎𝑅𝑃 𝐶𝑖, is
calcula ed by pe o ming he ime di e ences among RPC and he wo
on scin illa o s, 𝑆𝐶1and 𝑆𝐶2, in he elescope and esol ing he
ollowing sys em o equa ions:
⎛
⎜
⎜
⎝
110
101
011
⎞
⎟
⎟
⎠
⎛
⎜
⎜
⎜
⎝
𝜎2
𝑅𝑃 𝐶𝑖
𝜎2
𝑆𝐶1
𝜎2
𝑆𝐶2
⎞
⎟
⎟
⎟
⎠
=
⎛
⎜
⎜
⎜
⎜
⎝
𝜎2
𝛥𝑅𝑃 𝐶𝑖−𝑆𝐶1
𝜎2
𝛥𝑅𝑃 𝐶𝑖−𝑆𝐶2
𝜎2
𝛥𝑆𝐶1−𝑆𝐶2
⎞
⎟
⎟
⎟
⎟
⎠
(1)
whe e 𝜎𝑅𝑃 𝐶𝑖,𝜎𝑆𝐶1and 𝜎𝑆𝐶2a e he ime p ecision o 𝑅𝑃 𝐶𝑖,𝑆𝐶1
and 𝑆𝐶2 espec i ely, and 𝜎𝛥𝑅𝑃 𝐶𝑖−𝑆𝐶1,𝜎𝛥𝑅𝑃 𝐶𝑖−𝑆𝐶2and 𝜎𝛥𝑆𝐶1−𝑆𝐶2a e he
s anda d de ia ion o ime di e ence dis ibu ion o 𝑅𝑃 𝐶𝑖−𝑆𝐶1,
𝑅𝑃 𝐶𝑖−𝑆𝐶2and 𝑆𝐶1−𝑆𝐶2. Typical calcula ed iming p ecision o
he scin illa o s is a ound 35 ps (1 s anda d de ia ion). E iciency, 𝜖𝑖, o
each indi idual RPC, is calcula ed as he a io o he numbe o e en s
wi h signal in bo h ends o a gi en 𝑅𝑃 𝐶𝑖and he numbe o e en s wi h
signal in he h ee scin illa o s in he elescope. The 𝑆𝐶1scin illa o
has a e ical wid h o 20 mm, while he 𝑅𝑃 𝐶1and 𝑅𝑃 𝐶4ha e 22 mm,
he e o e a misalignmen be ween he RPCs and he scin illa o can
c ea e geome ic ine iciencies, as will be shown below. In addi ion,
due o he small size o he elescope, he e iciency ob ained should be
unde s ood as a lowe limi .
4. Resul s
Figs. 2a and 2b show he e iciency and iming p ecision as a
unc ion o he inciden pa icle lux densi y a a wo king empe a u e
o 21 ◦C and educed elec ic ield o 443 Td. Bo h igu es show he
loss o e iciency and de e io a ion o iming p ecision as he inciden
pa icle lux inc eases om 100 Hz/cm2up o 1500 Hz/cm2. Apa
om he al eady men ioned di e ence in e iciency (due o geome ical
easons) be ween he 22 mm and 44 mm RPCs, i is obse ed ha he
RPCs wi h 2 mm glass (𝑅𝑃 𝐶2and 𝑅𝑃 𝐶1) lose e iciency much as e
and ha e a wo se iming p ecision. This di e ence is due o wo ac o s.
On he one hand he hickness o he glass and on he o he hand he
esis i i y i sel which is 2–3 imes lowe in he 1 mm glass, gi ing in
combina ion a ac o o 4–6in esis ance.
Figs. 3a and 4a show he e iciency o RPC wi h 2 mm and 1 mm
hick glasses espec i ely as a unc ion o inciden pa icle lux om
100 Hz/cm2 o 1500 Hz/cm2 o h ee di e en ope a ing empe a u es
21 ◦C, 30.5◦C and 40.6◦C. The e iciency eco e y wi h inc easing
ope a ing empe a u e (due o dec easing esis i i y) is e iden , being
much highe o he 2 mm chambe s, due o hei highe esis ance.
Fo he 1 mm chambe he e iciency is basically independen o he
inciden pa icle lux (a leas up o 1500 Hz/cm2) o a empe a u e
o 40.6◦C. Figs. 3b and 4b show he iming p ecision o he same
condi ions men ioned o he e iciency. Again, he eco e y o he
2
A. Blanco, P. Fon e, L. Lopes e al. Nuclea Ins . and Me hods in Physics Resea ch, A 1045 (2023) 167652
Fig. 2. (a) E iciency and (b) iming p ecision o he RPC as a unc ion o he pa icle
lux o a educed elec ic ield o 443 Td and a wo king empe a u e o 21 ◦C. A spline
has been added o guide he eyes.
Fig. 3. (a) E iciency and (b) iming p ecision o he RPC wi h glass hicknesses o
2 mm as a unc ion o pa icle lux o h ee di e en wo king empe a u es: 21 ◦C,
30.5◦C and 40.6◦C. A spline has been added o guide he eyes.
iming p ecision is obse ed as he ope a ing empe a u e inc eases and
emains a a le el o abou 100 ps up o 1500 Hz/cm2 o he 1 mm
chambe s.
5. Conclusions
In his wo k we ha e shown ha inc easing he wo king empe a-
u e o a RPC can subs an ially imp o e i s coun ing a e capabili y. In
pa icula , indi idually shielded s ip-like RPC wi h an ac i e a ea o
Fig. 4. (a) E iciency and (b) iming p ecision o he RPC wi h glass hicknesses o
1 mm as a unc ion o pa icle lux o h ee di e en wo king empe a u es: 21 ◦C,
30.5◦C and 40.6◦C. A spline has been added o guide he eyes.
750 × 44 mm equipped wi h 4gaps o 0.270 mm, show app oxima ely
he same e iciency and iming p ecision, a ound 90% and 100 ps,
espec i ely, o e a ange o inciden pa icle luxes up o 1500 Hz/cm2
when hei wo king empe a u e is aised o 40.6◦C. This con as s
wi h a 20 pe cen age poin s loss o e iciency and a wo sening o iming
p ecision o mo e han 60 ps when ope a ed a 21 ◦C.
This way o imp o ing he coun ing a e capabili y o a RPC
de ec o can be e y in e es ing as i allows o ex end i s coun ing a e
capabili y in a e y simple way.
Decla a ion o compe ing in e es
The au ho s decla e ha hey ha e no known compe ing inan-
cial in e es s o pe sonal ela ionships ha could ha e appea ed o
in luence he wo k epo ed in his pape .
Acknowledgmen s
This wo k was suppo ed by Fundação pa a a Ciência e Tecnologia,
Po ugal, in he amewo k o he p ojec CERN/FIS-INS/0009/2019.
Re e ences
[1] L. Lopes, e al., Accu a e iming o gamma ays wi h high- a e esis i e pla e
chambe s, NIMA 573 (1) (2007) 4–7.
[2] L. Naumann, e al., Ce amics high a e iming RPC, NIMA 628 (1) (2011) 138–141.
[3] J. Wang, e al., De elopmen o mul i-gap esis i e pla e chambe s wi h low-
esis i e silica e glass elec odes o ope a ion a high pa icle luxes and la ge
anspo ed cha ges, NIMA 621 (1) (2010) 151–156.
[4] Valida ion o new esis i e ma e ials o RPCs, AIDA-2020-D13.1, 2020, h p:
//cds.ce n.ch/ eco d/2319919.
[5] D. González-Díaz, e al., The e ec o empe a u e on he a e capabili y o glass
iming RPCs, NIMA 555 (1) (2005) 72–79.
[6] D. Bel e , e al., Pe o mance o he low-ji e high-gain/bandwid h on -end
elec onics o he HADES RPC wall, TNS 57 (5) (2010) 2848–2856.
[7] A. Neise , e al., TRB3: a 264 channel high p ecision TDC pla o m and i s
applica ions, JINST 8 (12) (2013) C12043.
[8] L. Lopes, e al., Resis i e pla e chambe s o he pie e auge a ay upg ade, JINST
9 (10) (2014) C10023.
3
Upda e
Nuclea Ins . and Me hods in Physics Resea ch, A
Volume 1064, Issue , July 2024, Page
h ps://doi.o g/10.1016/j.nima.2024.169368DOI:
Nuclea Ins umen s and Me hods in Physics Resea ch A 1064 (2024) 169368
A ailable online 20 Ap il 2024
0168-9002/© 2024 Else ie B.V. All igh s ese ed.
Co igendum
Co igendum o “Imp o ing coun a e capabili y o iming RPCs by
inc easing he de ec o wo king empe a u e” [Nucl Ins um Me hods Phys
Res Sec A: Accel Spec om De ec Assoc Equip 1045 (1 Janua y
2023), 167652]
A. Blanco
a
,
*
, P. Fon e
a
,
b
, L. Lopes
a
, J. Sa ai a
a
a
Labo a o y o Ins umen a ion and Expe imen al Pa icles Physics, Coimb a, Po ugal
b
Coimb a Poly echnic - ISEC, Coimb a, Po ugal
The au ho s eg e ha ing o go en o include in he lis o ac-
knowledgemen s one o he p ojec s ha pa ially suppo ed his
esea ch. The co ec acknowledgemen s sec ion should ead:
This wo k was suppo ed by Fundaç˜
ao pa a a Ciˆ
encia e Tecnologia,
Po ugal, in he amewo k o he p ojec CERN/FIS-INS/0009/2019
and by he Eu opean Union’s Ho izon 2020 Resea ch and Inno a ion
p og amme unde G an Ag eemen AIDAinno a - No 101004761.
The au ho s would like o apologise o any incon enience caused.
DOI o o iginal a icle: h ps://doi.o g/10.1016/j.nima.2022.167652.
* Co esponding au ho .
E-mail add ess: [email p o ec ed] (A. Blanco).
Con en s lis s a ailable a ScienceDi ec
Nuclea Ins . and Me hods in Physics Resea ch, A
jou nal homepage: www.else ie .com/loca e/nima
h ps://doi.o g/10.1016/j.nima.2024.169368
