Detector R&D for Muon Chamber Anand K. Dubey For VECC group

CBM Muon detector requirements: Main issues:  The first plane(s) has a high density of tracks -- detector should be able to cope up with high rate. ~ 10 MHz/cm 2  good position resolution  Should be radiation resistant  Large area detector – modular arrangement  suitable options: micropattern gas detectors such as GEMs, Micromegas, and THGEMs.

MUCH R&D so far: we have assembled and tested double and triple GEM prototypes based on 10 cm x 10 cm GEM foils. Optimize the operating conditions with 10 cm x 10 cm. the detector should have: -- a high charged particle efficiency(>90%) -- a good dynamic range. -- a reasonable cluster size for tracking. -- a good rate handling capability In future we would like to go to 30 cm x 30 and later to foils with larger dimensions.

Schematic of prototype GEM chamber assembly GEMS Drift plane (inner side copper plated) 12 x cm 12 cm x 10 mm Readout PCB CERN made GEM foils obtained from Area: 10cm x 10cm Drift gap: ~7mm Induction gap: 1.5mm Transfer gap: 1mm In the next prototypes we have an O-ring on the perspex frame In order to facilitate quick changing on GEMs if needed.

Testing of GEM At the SIS 18 beam line using proton beams of 2.5 GeV/c Aim being : -- to test the response of the detector to charged particles. -- efficiency, cluster size, gain uniformity, rate capability -- testing with actual electronics for CBM : nXYTER -- testing with the actual DAQ -- Aug08-- first successful test with n-XYTER(with 64 channels bonded ) + GEM was performed. MIP spectra for 2GEMs and 3 GEMs were obtained. -- Aug-Sep 09, In 2009 a fuller version of nXYTER with all the 128 channels bonded was available. this offered a better configuration for efficiency estimation and also for cluster size estimation.

Readout Board for Test beam Aug-Sep 09 Inside view Outside view Two triple GEM chambers were fabricated : det 01 – with two different pad sizes(shown below) det02 -- same size pads but with larger induction gap Inside view

GEM chambers – Beamtest 2009

Aug-Sep09 test (with 2.3 GeV/c protons) Correlation between GEM1 and GEM2 pulse height spectra

ADC distribution of main cell and variation with HV 4 fold increase in ADC for a deltaV(GEM) increase by 50V

Time difference between trigger(aux) and GEM ROC Procedure: Get the GEM pads hit in nsec after last Aux. Offset + drift time Determining the Efficiency Using STS Hits

Eff_66 Efficiency with time HV= 3650HV= 3750 Looks like the detector takes some time to become stable, -- need more online investigations 95 % efficiency has been achieved by 3 GEM chamber used by the CMS upgrade group. The chamber tested in June2010.  next slide

12 Slides from Stefano Colaresi – CMS upgrade, RD51 miniweek, cm x 10 cm GEMs Readout: Strips of 0.8 mm pitch so 95 % efficiency is achievable things can be complicated with pads, -- one such large GEM with pad readout was tested in June analysis is still underway

Cosmic Ray test setup at VECC Setup for detector efficiency: 1. Detector+Ortec preamp+amp 2.Using MANAS coupled to PCI CFD card 3. Using Aux + nXYTER

Pedestal GEM signal connected to Channel 56 of FEE (MANAS) After pedestal subtraction - ADC of Channel 56 No of triggers( from 3 FOLD) = 187 Entries =158 => 85% Results with MANAS 64 channels for 4 MANAS

3GEM Pulse height distribution at different HV with MANAS HV =3550 (Vgem=394 V) HV=3600 HV 3650 HV =3725(Vgem=413) HV 3700 The MIP peak shifts with HV

Top copper Pad area- 67*73 Sq mm For 3mm. For 4mm - 88*97 sq mm  Main Features : Main Features :  Both 3 and 4mm square pad sizes Both 3 and 4mm square pad sizes  Not Staggered (‘09 test beam module) Not Staggered (‘09 test beam module)  Symmetric Square Pads Symmetric Square Pads  Multi Layers ( 4) with GND Planes Multi Layers ( 4) with GND Planes  Signal Tracks are distributed in 3 planes Signal Tracks are distributed in 3 planes Reduce the capacitance Track to Track spacing increases Reduce Cross talk  Blind Vias for gas integrity Blind Vias for gas integrity  Gnd Tracks between Signal Tracks Gnd Tracks between Signal Tracks Bottom copper Connector with resistors Top copper GND Plane Bottom copper GND Plane Connectors for FEBs Inner 1 Inner 2 16 Readout PCBS for Test beam 2010

MuCh Layout

Tracking station plane 2m ROC stack 3mt (approx) Placement of ROC Boards ROC stack 10 March Physics With FAIR: Indian Perspective, Susanta K Pal

-- CMS upgrade, slides from A. Sharma, RD51 miniweek, (1)

22 CMS Prototype GEM - Stack (2) Profile ~ 15 mm

CMS Prototype GEM - Test Box Large Drift Electrode Sample under test Jean-Paul Chatelain (3)

Inner 1Inner-2Bottom Copper Top copper Blind vias from inner layers( blue) Blind vias (red ) to inner layer 2.6 mm square pads  Pads arranged in one block of 32*8=256.  Connected to 300 pin connector.  Tracks - shorter and not closer.  can be easily duplicated for bigger sizes.  40 such FEE Boards for One Slat of 1mt. Length..  Each block read by 1 FEB with 2/4 n-XYTERs ( 128/64 Channels)  FEBs can be mounted horizontal or vertical  Modular Approach MUCH PCB design 10 March Physics With FAIR: Indian Perspective, Susanta K Pal

Gas out Conceptual sketch of Triple GEM chamber module Gas in Segmented LV power line/power plane on Detector PCB  each power line is feeding 5-FEBs  ground plane of LV line is in other layer of PCB HV 1 mt 10cm To be decided LV connector 40 FEBs in one module in 1mt slat with about channels 10 March Physics With FAIR: Indian Perspective, Susanta K Pal

Chamber PCB 4 sq mm pads. 32*32 Array(1024 pads). PCB active area is 135mm *135 mm. Read by 2 chip FEB(256 channels) Basic block=32*8 array. Track lengths are short. Bottom side Inner 2 layer Inner 1 layer Top side GND Plane Sa SAMTEC-300 Pin connectors 2chipFEBs

Chamber PCB with 4 FEBs Top view with 4 sq mm padsBottom view –Connectors for FEBs FEB 1FEB 4 FEB 2FEB 3 Bottom view of FEB

2 CHIP FEB –PCB Top Copper Bottom copper N-XYTER 8 layer PCB. Size =111mm*31mm No scooping for N XYTER on the PCB. Regulators - on top copper. Filter capacitors- on bottom copper ADC ROC Connector 300 Pin SAMTEC Connector

 Double and Triple GEMs have been assembled at VECC. Tests performed with radioactive sources as well with proton beams at GSI.  Test with proton beams : Double GEM and triple GEMs coupled to the first prototype of n-XYTER readout chip. – preliminary response looked encouraging. -- charged particle detection efficiency needs to be still higher. investigations underway, using tests with cosmic rays.  Next test beam: two chambers of 3x3 sq. mm 4x4 sq. mm chamber would require 8 FEBs.  Several layout s of the actual design of the Muon Chamber under discussion. Actual size of large GEMs for the final chamber under consideration –- keeping informed with the CMS upgrade involving triple GEMs. SUMMARY

Thanks For Your Attention

BACKUPS

Readout plane-bottom Copper 68 Pin connectors for FEB 1nXGen 68 Pin connectors for FEB 1nXGen Resistors for input Protection ERNI Part no No –68Pins

Triple GEM: Test with Fe-55 3GEM : Gain vs. Vgem