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Update on RICH Upgrade Simulations

S.Easo,16-10-2012

RICH Upgrade meeting

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Outline

• Feasibility of the two-RICH option for upgrade.

• Last meeting: Results from using current optics / ‘modified optics’ for RICH1

‘Modified optics’ suffered PID performance loss due to acceptance effects although it reduced the peak occupancy by 50%.

• This presentation:

Further modifications to the RICH1 optics to avoid acceptance effects

Comparison of PID performances

Plans

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Optics Modifications

• Spherical mirror ROC= 2710 3800 mm (same as version2)

• Spherical mirror tilt = 240 mrad (current optics ~ 315 mrad, version2 ~ 200 mrad)

• Flat mirror: mirror segment sizes increased by 30%, but kept the same location for edge nearest to the beampipe as in version2.

• Photodetector planes tilted accordingly.

Photon: angle of incidence on PMT plane.

Mean=38 mrad

• PMT modules 5 rows7 rows in each panel of RICH1.

Optics-Version3

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RICH1 Optics

Optics-Version3

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RICH1 – Optics verifications

Optics-Version3

Particle Gun at 280 310 mrad

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Optics-Version3Particle gun at 25 35 mrad

RICH1 Optics Verifications

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RICH1 Optics verifications

Cherenkov angle reconstructed in Particle gun events

Width=0.72 mrad

Optics Version3

RICH1 yieldMean=36

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Datasets and simulation options

• Gauss v42r1, Brunel v44r0

Luminosity cm-2 s-1

Beam Energy (TeV)

Spill Over Photo-Detector

Lumi2-S 2 x 10 32 3.5 No PMT-SBA

Lumi20-S 20 x 10 32 7 No PMT-SBA

• All PMT data with SBA-Borosilicate version of PMTs. All data without Aerogel

• Signal events of Bs ff for PID studies

• About 20 K events used for each option

Current-Optics RICH1- Spherical Mirror ROC=2710 mm

Rich1-Optics-Version3 RICH1-Spherical MirrorROC=3800 mm and optics tuning

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PID performance at Lumi2

This version of ‘new optics’ has better performancecompared to ‘current optics’.

Current-Optics

RICH1-Optics-Version3

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PID performance at Lumi20

Current-Optics

RICH1-Optics-Version3

This new optics has better performance.

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PID comparisons

Performance loss due to Lumi2 Lumi20 is mostly recovered by improved optics. (ie. ‘Red ’ marginally below the ‘black ’ ).

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dll_K > 0.0dll_K >4.0

Lumi20-S, Current Optics

dll_K >0.0dll_K > 4.0

Lumi2-S, Current optics

MeV MeV

MeV MeV

K K efficiency p misID probability

PID vs. Momentum

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dll_K >0.0

PID vs. Momentum Lumi2-S, RICH1-Optics-Version3

dll_K > 4.0

dll_K >0.0 dll_K > 4.0

Lumi20-S, RICH1-Optics-Version3

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Epilogue

• The number of PMTS 1920 2688 in RICH1 2688= 12*7*2*16

Possibilities to reduce this: (a) Have a sparse distribution of PMTs near the outer edges of the acceptance. May be tried to to see the effect on PID (b) Limit the acceptance to a smaller value.

• Rotating RICH1 : Not done yet.

• Number of scintillation hits in RICH2 : to be improved.

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Summary

Improvements in the optics configuration resulted in improving the PID performance.

Possibilities exist for further improvements in PID performance and to reduce the number of PMTS used.

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BACKUP SLIDES

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PID vs Angle

In all plots dll_K > 4.0

9.3GeV<P < 30 GeV

Lumi20-Smrad

9.3GeV<P < 30 GeV

Lumi2-S

mrad

K K efficiency p misID probability

9.3GeV<P < 30 GeV

Current Optics RICH1-Optics-Version3

mrad

mrad

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RICH1-Optics-Version3

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Resolutions from Brunel

RICH1-Optics-Version3

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P PT

Track polar angle

MeV MeV

mrad

Track Parameters

Tracks used in RICH PID algorithm

Lumi2-S

Current-Optics