Towards EE/HE detectors performance with coverage up to |η|=4
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Transcript of Towards EE/HE detectors performance with coverage up to |η|=4
October, 2013 Towards EE/HE detectors performance with η up to 4 1
Towards EE/HE detectors performance with coverage
up to |η|=4
I.Kurochkin, A.Dabrowski*, H.Vincke DGS-RP-AS, CERN*CMS-BRIL, CERN
For CMS Upgrade Project
Outline Motivation From the conceptual design towards FLUKA models with |η|
up to 4: step by step New FLUKA nominal model (Model NN) Model 0 Model A Model B
The radiation environment of the CMS detectors: neutron flux density and 1MeV-neutron equivalent fluence
Data comparison Summary & discussion
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Motivation Goal
Estimate the radiation environment of the CMS detectors due to CMS central vacuum beam pipe upgrades and EE/HE upgrades towards a CMS detector performance with coverage up to |η| = 4.
Sub-goal Try to define possible realistic scenarios towards a CMS
detector performance with coverage up to |η| = 4 using a conceptual design by A.Surkov, some mechanical limits and approaches.
Towards EE/HE detectors performance with η up to 4
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Towards new conceptual design for CMS
Any conceptual design for the EE/HE detector performance with coverage up to |η| ≤ 4 has not approved yet.
No drawings available for the EE/HE detectors with coverage up to |η| ≤ 4.
Towards EE/HE detectors performance with η up to 4
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FLUKA simulation: CMS scenario after LS1
Units p-p
E TeV/n 7
TeV 14
Crossing µrad ±142.5
Vertex spread cm 5.0
cm-2 s-1 1.0·1034
days 180
mb 85
R = · L s-1 8.5·108
Note*. Data are normalized on nominal luminosity and irradiation time of 180 days.
First step: New CMS central beam pipe
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Collar(AMC640XA) Al-alloy flange(AA2219) Steel flange(ANSI316LN)
LHCVC5C_0029-v0.plt and data from vacuum group (P.Lepeule & M.Gallilee)
Be-bp (S200F) Al-alloy bp (AA2219)
First step: Comparison with previous data
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Flange Joint
First step: Comparison with previous data
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Neutron flux density in layer at z =272 cm
First step: Comparison with previous data
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1 MeV neq fluence in layer at z =272 cm
Summary I
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The implementation of the new CMS beam pipe changes the particles flux density close the beam pipe which are very sensitive to fine structure of the beam pipe. The particles flux density decrease up to a factor of 2 close to massive elements: joints and flanges.
At a distance of more than 50 cm from the beam line values of the particles flux density are similar as for “nominal” input .
Values of the neutron flux density and silicon 1 MeV-neutron equivalent fluence in the last layer (z = 272 cm) of the silicon tracker did not change much.
Second step: towards η up to 4 (model 0)
Conceptual design by A.Surkov Approaches: The new CMS central beam pipe TOTEM removed Rescale for Al-cone/flange
(conceptual design by A.Surkov for cone angle ~ 2.8º)
Rescale for Preshower elements Al-plate (correct size, but old
position) Sizes of EE/HE up to |η| < 4 Rescale of back flange (new design),
gap - 20 mm Rescale of PE – shielding between
EE/HE Modified PE – shielding (to extend
up to |η| < 4)
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Second step: Model 0
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Second step: Neutron flux density in silicon tracker
FLUKA model 0 towards η up to 4
FLUKA nominal model & new central beam pipe
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R = 8.5·108 p-p int./s
Second step: Neutron flux density in silicon tracker
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𝑅𝑛=𝜑𝑀 0
𝜑𝑀𝑁𝑁Neutron flux density in layer at z =272 cm
Second step: Silicon 1 MeV-neutron equivalent fluence in silicon tracker
FLUKA nominal model & new central beam pipe
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FLUKA model 0 towards η up to 4
R =1.32·1016 p-p int./year
Second step: Silicon 1 MeV-neutron equivalent fluence in silicon tracker
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= 1 MeV neq fluence in layer at z =272 cm
Second step: Particle spectra in silicon tracker 272 cm <z < 272.05 (model 0)
2.6 < η < 2.83 2.2 < η < 2.6
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R = 8.5·108 p-p int./s
Second step: Particle spectra in silicon tracker 272 cm <z < 272.05 (model 0)
1.8 < η < 2.2 1.65 < η < 1.8
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R = 8.5·108 p-p int./s
Second step: Neutron spectra in silicon tracker 272 cm <z < 272.05 (model 0&NN)
2.6 < η < 2.83 2.2 < η < 2.6
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R = 8.5·108 p-p int./s
Second step: Neutron spectra in silicon tracker 272 cm <z < 272.05 (model 0 & NN)
1.8 < η < 2.2 1.65 < η < 1.8
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R = 8.5·108 p-p int./s
Second step: Comparison
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Particles 2.6 < η < 2.83 2.2 < η < 2.6 1.8 < η < 2.2 1.65 < η < 1.8Protons 1.09 1.08 1.09 1.04Neutrons > 20 MeV 1.77 1.73 1.61 1.48Neutrons <20 MeV 2.27 2.00 1.73 1.62Pions 1.06 1.04 1.03 1.04Muons 1.00 1.02 1.04 1.00E+/E- 1.13 1.15 1.15 1.18Photons 1.60 1.58 1.50 1.42
Ratio of particles flux density of model M0 to model NN for four η-bins in last layer (z = 272 cm) of silicon tracker
Next step: towards η up to 4: model A&B
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Crucial points
EE must be free moved at 10.4 m during maintenance when CMS open
Mechanical limits
Al-cone Endcap bpipe
Model A: Preshower and alignment system remain
Model B: Preshower and alignment system will not be installed
Radial limits ~ 20 cm
Next step: model A
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Model A (with preshower&alignment system): Al-cone as in nominal input, |η| ≤ 3.0 for EE, |η| ≤ 3.68 for HE, new design of back flange.
Next step: Neutron flux density in silicon tracker
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𝑅𝑛=𝜑𝑀𝐴
𝜑𝑀𝑁𝑁 Neutron flux density in layer at z =272 cm
Model NN – “nominal” model & new CMS central beam pipe;Model 0 - full rescale of model NN; Model A - Al-cone as in nominal input, |η| ≤ 3.0 for EE, |η| ≤ 3.68 for HEModel B - Al-cone (rescale), no preshower (air), |η| ≤ 3.3 for EE, |η| ≤ 3.68 for HE
Next step: Silicon 1 MeV-neutron equivalent fluence in silicon tracker
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= 1 MeV neq fluence in layer at z =272 cm
Model NN – “nominal” model & new CMS central beam pipe;Model 0 - full rescale of model NN; Model A - Al-cone as in nominal input, |η| ≤ 3.0 for EE, |η| ≤ 3.68 for HE Model B - Al-cone (rescale), no preshower (air), |η| ≤ 3.3 for EE, |η| ≤ 3.68 for HE
Next step: model B
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Model B (without preshower&alignment system): Al-cone is limited by EndCap beam pipe, |η| ≤ 3.3 for EE, |η| ≤ 3.68 for HE, new design of back flange.
Next step: Neutron flux density in silicon tracker
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𝑅𝑛=𝜑𝑀𝐵
𝜑𝑀𝑁𝑁 Neutron flux density in layer at z =272 cm
Model NN – “nominal” model & new CMS central beam pipe;Model 0 - full rescale of model NN; Model A - Al-cone as in nominal input, |η| ≤ 3.0 for EE, |η| ≤ 3.68 for HEModel B - Al-cone (rescale), no preshower (air), |η| ≤ 3.3 for EE, |η| ≤ 3.68 for HE
Next step: Silicon 1 MeV-neutron equivalent fluence in silicon tracker
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= 1 MeV neq fluence in layer at z =272 cm
Model NN – “nominal” model & new CMS central beam pipe;Model 0 - full rescale of model NN; Model A - Al-cone as in nominal input, |η| ≤ 3.0 for EE, |η| ≤ 3.68 for HEModel B - Al-cone (rescale), no preshower (air), |η| ≤ 3.3 for EE, |η| ≤ 3.68 for HE
FLUKA simulation: Neutron flux density in silicon tracker
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R = 8.5·108 p-p int./s
• Model NN – “nominal” model & new CMS central beam pipe;• Model 0 - full rescale of model NN; • Model A - Al-cone as in nominal input, |η| ≤ 3.0 for EE, |η| ≤ 3.68 for HE• Model B - Al-cone (rescale), no preshower (air), |η| ≤ 3.3 for
EE, |η| ≤ 3.68 for HE
FLUKA simulation: Silicon 1 MeV-neutron equivalent fluence in silicon tracker
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• Model NN – “nominal” model & new CMS central beam pipe;• Model 0 - full rescale of model NN; • Model A - Al-cone as in nominal input, |η| ≤ 3.0 for EE, |η| ≤ 3.68 for HE• Model B - Al-cone (rescale), no preshower (air), |η| ≤ 3.3 for
EE, |η| ≤ 3.68 for HE
R =1.32·1016 p-p int./year
FLUKA simulation: Neutron flux density in EE layer of electronics (z = 342 cm)
September, 2013 BRIL Radiation Simulation Meeting 31
R = 8.5·108 p-p int./s
FLUKA simulation: Silicon 1 MeV-neutron equivalent fluence in EE layer of electronics (z = 342 cm)
September, 2013 BRIL Radiation Simulation Meeting 32
R =1.32·1016 p-p int./year
Summary II
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Possible radiation impact on sensitive elements of CMS detector has been estimated for three models with η up to 4.
Model 0 and model B show significant growth of the neutron flux density (~1.5-3.0) and 1 MeV-neutron equivalent fluence in the silicon tracker system (~1.2-3.5)
Results of simulation are very sensitive to details of design and material budget.
Without the Endcap beam pipe upgrades it’s not possible to reach the required η-coverage.
Next step – realistic design and material budget, the optimization of shielding between tracker and EE to reduce radiation impact on silicon tracker system.
Appendix: Particle spectra in silicon tracker 272 cm <z < 272.05 (model NN)
2.6 < η < 2.83 2.2 < η < 2.6
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R = 8.5·108 p-p int./s
Appendix: Particle spectra in silicon tracker 272 cm <z < 272.05 (model NN)
1.8 < η < 2.2 1.65 < η < 1.8
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R = 8.5·108 p-p int./s