ATLASandCMSRPCphase2.201405v2

CMS RPC R&D for phase 2
Two types of upgrades proposed for
the CMS RPC muon system:
1. Aging and longevity: installed
in 2007, must continue to
operate without significant
degradation well beyond the
design expectations of the LHC;
in particular, with respect to a
large integrated radiation dose
and also a very long time
period of operation.
2. Redundancy in the forward region: keep performance of trigger
and low pT threshold even at an increased luminosity
• HZZ*2m, 4m; Ht+t-mX; etc
• NEW STATIONS RE3/1 and RE4/1
D.Boscherini for the ATLAS Coll. and S.Bianco for the CMS Coll. R&D RPC phase2 - Rome May 9th 2014
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RE3/1 & RE4/1
• Proposed to cover the
very forward region
(1.6< |h| <2.4)
– 144 chambers (about 1.5-2.0 m2 area) for the inner
(ring n.1) region of disks 3 and 4
– Rate: 1-2 kHz/cm2
•  x5 limit tested for existing RPC chambers
– Integrated charge: 1-2 C/cm2 @ 3000fb-1
D.Boscherini for the ATLAS Coll. and S.Bianco for the CMS Coll. R&D RPC phase2 - Rome May 9th 2014
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CMS RPC in muon reconstruction
D.Boscherini for the ATLAS Coll. and S.Bianco for the CMS Coll. R&D RPC phase2 - Rome May 9th 2014
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Joint ATLAS-CMS phase 2 R&D
CMS-specific
• Operation at 1-2kHz/cm2, 1-2 C/cm2 @3000fb1
• Improved time resolution (10-100)ps
– Background reduction
– Secondary vertices
• iRPC
– Large area, improved, multigap RPC
• with HPL / glass electrodes
D.Boscherini for the ATLAS Coll. and S.Bianco for the CMS Coll. R&D RPC phase2 - Rome May 9th 2014
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ATLAS RPC phase-2 proposal
Completion of the detector for the barrel muon trigger via the installation of
new trigger stations in the inner layer of the spectrometer (currently
equipped only with MDTs)
Increase the number of measurement stations from 2  3
Increase the number of independent layers from 6  9
RPC3
RPC2
RPC1
RPC0
(BI)
D.Boscherini for the ATLAS Coll. and S.Bianco for the CMS Coll. R&D RPC phase2 - Rome May 9th 2014
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ATLAS RPC phase-2 proposal
The inner layer was already considered in the original project of the barrel
trigger detector, but at that time the need for the 3rd station was not
stringent and it was cancelled
Trigger performance improvements with the new RPC inner layer:
- larger acceptance
The new chambers will substantially increase the trigger coverage by
filling the acceptance holes due to the barrel toroid support structures
- increased selectivity
The larger lever arm and the improved spatial and time resolution of the
new RPCs will allow to apply a sharper momentum cut
- increased chamber redundancy and longevity
the new layer will increase the redundancy well above the current 3/4
low-pt majority. This will also allow to operate the middle chambers at
lower voltage, decreasing the integrated charge, without loss in the
overall trigger efficiency
D.Boscherini for the ATLAS Coll. and S.Bianco for the CMS Coll. R&D RPC phase2 - Rome May 9th 2014
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Barrel trigger coverage
High-Pt trigger acceptance currently limited at ~72%
due to non-instrumented regions in:
- feet + elevators (partial recovery in LS1)
- toroid (and ribs) in BM chambers of small sectors
LVL1 barrel
Holes are not projective and 3/3 RPC chambers
are required in the trigger
 with RPC BI chambers use 3/4 request
η=0.0
0.4
0.75
1.0
D.Boscherini for the ATLAS Coll. and S.Bianco for the CMS Coll. R&D RPC phase2 - Rome May 9th 2014
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Barrel trigger coverage
Single muon MC study
for different trigger options
current
trigger logic
Trigger requirement
Acceptance wrt muon
reconstruction, ηmuid<1.05
RPC1 && RPC2 && RPC3
72%
RPC0 && (RPC1||RPC2) && RPC3
82%
any 3 out of 4 chamber layers
88%
(any 3 out of 4) || ( inner && outer) 96%
D.Boscherini for the ATLAS Coll. and S.Bianco for the CMS Coll. R&D RPC phase2 - Rome May 9th 2014
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Redundancy exploitation
The produced charge, responsible for the
detector aging, can be reduced
by decreasing the operating voltage
(this is equivalent to work at lower rate and
much lower current)
The detector efficiency will consequently
decrease
1.2
Efficiency
1
0.8
0.6
0.4
0.2
0
8500
9000
9500
10000
Standard voltage (V)
- the loss in efficiency is compensated by a less
stringent requirement in low-pt trigger:
3/4  2/4 majority
- the rejection power would be guaranteed by
the additional RPC in the BI chambers
2/4
3/4
D.Boscherini for the ATLAS Coll. and S.Bianco for the CMS Coll. R&D RPC phase2 - Rome May 9th 2014
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Requirements on the new RPCs
According to Atlas requirements the qualification tests were done taking as reference
luminosity L=1034 cm-2 s-1, assuming 10 years of running at max background rate of
100 Hz/cm2 (including a safety factor of 5 wrt simulation)
Expected max rate in new inner layer ~1 kHz/cm2:
need to improve the long term RPC rate capability to sustain the LHC luminosity in
phase-2
Limited space available for the installation in the inner layer: ~5cm
Reduced gas gain:
- thinner gap 2  1 mm
- thinner electrodes 1.8  1.2 mm
- increased amplification in front-end electronics
Improved spatial and time resolution:
- timing is improved by reducing the gap thickness
- use ToT and charge centroid to improve spatial resolution
Reduced detector thickness
- higher-quality mechanical structures
D.Boscherini for the ATLAS Coll. and S.Bianco for the CMS Coll. R&D RPC phase2 - Rome May 9th 2014
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1. Electrode
D.Boscherini for the ATLAS Coll. and S.Bianco for the CMS Coll. R&D RPC phase2 - Rome May 9th 2014
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2. Chamber prototypes
D.Boscherini for the ATLAS Coll. and S.Bianco for the CMS Coll. R&D RPC phase2 - Rome May 9th 2014
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3. FEE
D.Boscherini for the ATLAS Coll. and S.Bianco for the CMS Coll. R&D RPC phase2 - Rome May 9th 2014
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4. The Quest for Ecogas
• Qui lista candidati, piano misure, setups
disponibili a frascati e TV
D.Boscherini for the ATLAS Coll. and S.Bianco for the CMS Coll. R&D RPC phase2 - Rome May 9th 2014
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The Quest for Ecogas
characterizing interaction of candidates with RPC materials
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Chemistry
Reactivity
Outgassing
HF production
Before and after irradiation
D.Boscherini for the ATLAS Coll. and S.Bianco for the CMS Coll. R&D RPC phase2 - Rome May 9th 2014
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Setup and refs for materials studies
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•
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•
•
•
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•
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Op4cal sensors for RPC gas
–
M.Caponero et al., Use of fiber op4c technology for rela4ve humidity monitoring in RPC
detectors JINST 8 (2013) T03003
–
S.Grassini et al., Gas monitoring in RPC by means of non-‐invasive plasma-‐coated POF
sensors JINST 7 (2012) P12006
–
Patent deposit ZEOSENSORS (n. RM2011A000621 24/11/2011)
•
Gas mixtures for RPC
–
S.Colafranceschi et al., A study of gas contaminants and interac4on with materials in RPC
closed loop systems JINST 8 (2013) T03008
–
S.Colafranceschi et al., Performance of the Gas Gain Monitoring system of the CMS RPC
muon detector and effec4ve working point fine tuning INST 7 (2012) P12004
–
L.Benussi et al., A New approach in modeling the response of RPC detectors
Nucl.Instrum.Meth. A661 (2012) S182-‐ S185
–
L.Benussi et al, Study of gas purifiers for the CMS RPC detector Nucl.Instrum.Meth. A661
(2012) S241-‐S244
•
Materials for GEM
–
G.Saviano et al., A study of film and foil materials for the GEM detector proposed for the
CMS muon system upgrade accepted by JINST (2014)
D.Boscherini for the ATLAS Coll. and S.Bianco for the CMS Coll. R&D RPC phase2 - Rome May 9th 2014
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5. Irradiation tests
D.Boscherini for the ATLAS Coll. and S.Bianco for the CMS Coll. R&D RPC phase2 - Rome May 9th 2014
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Single Event Effects study on the FE boards of the
improved RPC
(2015-2017)
•
Motivations: study of radiation transient effects
on the FE electronics of the iRPC
•
Study : cross section measurement of the
transient fenomena induced by neutrons on
the open input FE boards. We plan to use the
following facilities: the Triga Mark II reactor in
Pavia and the Louvain cyclotron. The first one
covers a energy range till 18MeV which can be
extended till 50MeV by the second one.
•
Setup : a measurement station has been
already assembled and used for previous tests.
The station has been instrumented with : VME
crate, LVoltage PS , VME scalers, NIM crate and
NIM modules, PC.
•
Additional costs to be addressed:
–
irradiation and targets for flux measurement at
Triga Mark II  4kEuro
–
irradiation and transport costs for Louvain 
7kEuro
spares
D.Boscherini for the ATLAS Coll. and S.Bianco for the CMS Coll. R&D RPC phase2 - Rome May 9th 2014
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HPL: R&D relativo alla produzione di lastre di HPL a bassa resistività. Obiettivo è il
raggiungimento di un valore di resistività inferiore di un ordine di grandezza rispetto
a quello attualmente utilizzato (1÷6 x 1010 Ohm cm).
Questo R&D è di interese comune ATLAS-CMS ma sarà seguito da CMS che ha
studiato e contribuito allo sviluppo della produzione di HPL per RE4 con una nuova
ditta di laminati (Puricelli) dopo la chiusura della ditta Panpla che aveva prodotto
tutto l’ HPL per gli RPC degli esperimenti a LHC. La misura di resitività sarà fatta da
CMS mentre il test della long term conductivity da ATLAS
Tot
35
HPL
20
Transportation
5
Resistivity Meas
10
• Acquisto di un batch di HPL (1 batch= 80 lastre da 1.6 m x 3.2 ;) . Questo quantitativo è
sufficiente per un certo numero di prototipi da 1mq per entrambi gli esperimenti e per
circa 5 prototipi0 (fulls size) per ogni esperimento : 8 kEuro
• Sperimentazione bassa resistività presso la ditta Puricelli : 12 kEuro (basato su circa 50
test )
• Misure di resistività: costruzione di uno strumento portatile per la misura di resistività
(alimentatore,adc,elettrovalvole, consumables) 7 keuro
• Test di long term conductivity sull’HPL : 3 keuto
• Trasporti: le lastre saranno tagliate presso una ditta milanese e inviate alla GT per la
costruzione dei prototipi: 5 keuro