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


October, 2013 3

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

October, 2013 4

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

?


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


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


Flange Joint



Neutron flux density in layer at z =272 cm



1 MeV neq fluence in layer at z =272 cm

Summary I


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)


Second step: Model 0


Second step: Neutron flux density in silicon tracker

FLUKA model 0 towards η up to 4

FLUKA nominal model & new central beam pipe


R = 8.5·108 p-p int./s

Second step: Neutron flux density in silicon tracker

September, 2013 Towards EE/HE detectors performance with η up to 4 14

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


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


= 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


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


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


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


R = 8.5·108 p-p int./s

Second step: Comparison


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


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

September, 2013 BRIL Radiation Simulation Meeting 23

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


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



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


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


𝑅𝑛=𝜑𝑀𝐵

𝜑𝑀𝑁𝑁 Neutron flux density in layer at z =272 cm


Next step: Silicon 1 MeV-neutron equivalent fluence in silicon tracker




FLUKA simulation: Neutron flux density in silicon tracker


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


• 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)


R = 8.5·108 p-p int./s

FLUKA simulation: Silicon 1 MeV-neutron equivalent fluence in EE layer of electronics (z = 342 cm)


R =1.32·1016 p-p int./year

Summary II


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


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


R = 8.5·108 p-p int./s

Towards EE/HE detectors performance with coverage up to |η|=4

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