Gap Production for Upscope of the Endcap RPCs Sung Keun Park Korea Detector Laboratory Korea...
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![Page 1: Gap Production for Upscope of the Endcap RPCs Sung Keun Park Korea Detector Laboratory Korea University February 5, 2010 Workshop on the Forward CMS RPC.](https://reader030.fdocuments.net/reader030/viewer/2022032722/56649f4f5503460f94c70889/html5/thumbnails/1.jpg)
Gap Production for Upscope of the Endcap RPCs
Sung Keun Park
Korea Detector Laboratory Korea University
February 5, 2010
Workshop on the Forward CMS RPC Upscope
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1. Contributions to Forward RPC
1) R&D of Gap production - Since 1997
2) Gap production KODEL in charge of production and QC for gaps for all the RE RPCs. - Low eta : RE 1/2, 1/3, 2/2, 2/3, 3/2, 3/3 (432 RPCs, 1548 gaps produced) - Upscope Low eta : RE2bis (288 RPCs) - High eta : RE1/1, RE2/1, RE3/1
3) Installation of 4 prototypes of RE1/1
4) R&D of HPLs
5) R&D for Upgrade
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Silk screen method for graphitecoating (100 ~ 200 k/square)
PET film coating
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Gap assembly Linseed oil coating
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200 mCi 137Cs gamma irradiation facility & DAQ + electronics 200 mCi 137Cs gamma irradiation facility & DAQ + electronics
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Barrel RPCs Low-η
Forward RPCs
High-η Forward RPCs (Plan)
4-th station (Plan)
RE1/1
1) R&D of RE1/1 RPCs at CMS nose cones
2. R&D activities
![Page 7: Gap Production for Upscope of the Endcap RPCs Sung Keun Park Korea Detector Laboratory Korea University February 5, 2010 Workshop on the Forward CMS RPC.](https://reader030.fdocuments.net/reader030/viewer/2022032722/56649f4f5503460f94c70889/html5/thumbnails/7.jpg)
RE1/1 Design for RE1/1 in 1.6<<2.1
- 6 RE1/1 RPC modules tested for cosmic rays
- 4 RE1/1 RPCs installed
RE1/1 RPCs : 10 degree trapezoidal36 RPC modules on each wing
![Page 8: Gap Production for Upscope of the Endcap RPCs Sung Keun Park Korea Detector Laboratory Korea University February 5, 2010 Workshop on the Forward CMS RPC.](https://reader030.fdocuments.net/reader030/viewer/2022032722/56649f4f5503460f94c70889/html5/thumbnails/8.jpg)
![Page 9: Gap Production for Upscope of the Endcap RPCs Sung Keun Park Korea Detector Laboratory Korea University February 5, 2010 Workshop on the Forward CMS RPC.](https://reader030.fdocuments.net/reader030/viewer/2022032722/56649f4f5503460f94c70889/html5/thumbnails/9.jpg)
2) R&D of HPLs
Feasibility study for HPLs - A local HPL factory in Korea (Meltech). - Thin melamine-paper cladding on both surfaces of bakelite - The range of resistivity : 2 ~ 10 10ⅹ 10 cm. - Maximum size of HPLs : 2450 mm 1245 mm ⅹ
Quality Assurance for the HPL - KODEL built tools for resistivity measurement
Recent procurement of HPLs for multigap RPCs - Thickness : 0.5 - 1 mm for the multigap structure - The test results of the small prototype to be presented in RPC2010 workshop
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Resistivity tests for HPLs consisting of Melamine + Phenol sheets
Batch1 : 20 samples of 0.5 mm melamine-phenol-melamine Batch2 : 20 samples of 0.5 mm melamine-phenol-melamine Batch3 : 15 samples of 1.0 mm melamine-phenol-melamine
Batch 1
Batch 2 Batch 3
)Tá(T
Tb eññ 020 −=
α = 0.12/°C
Mean humidity ~ 75 %
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3) R&D of multigap RPCs
R&D for high-rate triggers at RE1/1 for future CMS Higher rate capability ← lower avalanche charge - Rate capability ~ 1 /<qe> - Rate capability ~ 1/ ρ
Then, what if multigap RPCs with HPLs ? - <Qe> ~ 10 times smaller than CMS RPCs - HPL : Melamine+Phenol → ρ < 1011 - Oiling required to reduce noises
0.6 ~1.1 pC
80 ~150 fC
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For 6-gap RPCs (without gamma rays) TDC threshold = 1 mV ADC thresholds = 80 ~ 150 fC (in offline analysis)
Mean qe at the efficiency plateau region → At 11.8 kV, ε = 0.97 (by TDC) and qe = 0.61 pC → At 12.7 kV, ε = 0.98 (by TDC) and qe = 1.12 pC
ε = 0.96 ε = 0.96
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Tests with gamma rays
A 6-gap RPC installed at a 200 mCi 137Cs gamma source (0.662 MeV) for high-rate background test - Accidental coincidences (geometrical) ~ 10 %
45 cmS
- Current activity of the source ~ 156 mCi = 5.77 GBq Distances Nγ (kHz/cm2) Nγ (signal) (kHz/cm2) -------------------------------------------------------------------------- 35 cm 375.0 3.38 (estimation) 45 cm 226.9 2.02 (measured at 13.97 kV) 55 cm 151.9 1.37 (estimation)
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Muon data with gamma background
- Shifts in HV ~ 1.5 kV at 2.02 kHz/cm2 - Caused by increase in resistivity of HPL ρ20 = (6.9 ± 3.5) 10ⅹ 10 Ωcm (at H = 75%) in Jul. 15, 2009 (right after the production) ρ20 = (3.3 ± 0.8) 10ⅹ 11 Ωcm (at H = 47%) in Jan. 6, 2010 (final measurement)- Resistivity of HPL should be ≤ 1011 Ωcm after fully polymerized .
Mean charges
Efficiencies & mean charges Efficiencies & cluster sizes
Future R&Ds
- QC for HPL - Test of prototype 6-gap RPCs for RE1/1 - Aging study with high gamma backgrounds
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3. Summary and Conclusion
1) Gap production - KODEL is ready for production and QC of the gaps for upscope - Gap production facility is well maintained
2) Other areas to contribute- Assembly of chambers- Electronics- High eta : RE1/1 (72 RPCs), RE2/1 (36 RPCs), and RE3/1 (36 RPCs)
3) R&Ds - HPL- RE1/1 (Multigap RPC, GEM)