VFAT Test Beam Analysis

Motivation

VFAT Analysis focused on time resolution results but we also measured :

• Spatial Resolution
• Cluster Size
• Cluster Size distribution
• Efficiency

Setup used in November 2012 Test Beam campaign

Beam Test@RD51 Setup

• 3 Trackers:10x10 triple GEMs
• 1 Timing GEM
• CMS-GEM prototypes:GE11-I & GE11-IV
• 3 Scintillators for Trigger
• DAQ with VFAT and APV, different ntuples created

The external trigger is given by the coincidence between the discriminated signals of 3 scintillators: two of them are mounted in contact in front of the tracking GEMs and the last one is located on the other side of the telescope.

Tracker GEMs : 10 x 10 triple GEM equipped with 2d readout Strips with pitch of 0.4mm (2 layers under 90 degrees to provide 2d measurement)

Readout

Data were acquired from the VFAT2 chips with TURBO front-end electronics

VFAT2: binary electronics, 8 VFATs in each turbo

Detector tested

• 2 Large Chamber without spacers (NS2 technic) ➜ self-streching, no glue, re-opening
• No spacers in the active area (99 x 22 x 44.5 cm)
• 3-1-2-1 mm gap configuration
• 2 Sectors tested with pitch 0.83 mm and 0.88 mm (VFAT tested only line4 (0.88mm))
• Test beam with muon and pion beam@150 GeV

Analysis approach

Analysis Steps

Used TURBO Analysis Software ➜ 3 different ntuples

• Event Builder : converted channel hits into the cluster with spatial coordinates
• Track Finder : extracted tracks
• Analyzer : with output of tracks, calculation of efficiency, cluster size, etc.

Configuration Files

• Offset Flip Event Builder VFAT: all detector names, x and y offsets, flips
• Offset Tracker: trackers and z offset of 3 trackers
• Offset And Coverage: z offset and efficient radius of timing GEM and the chambers

* Detector configuration file:

Run analyzed

Alignment procedure

• Runned EventBuilder with all offset in OffsetFlip_EventBuiderVFAT.conf set to zero

• Checked the Output file after this step

• Runned again EventBuilder with all offset in OffsetFlip_EventBuiderVFAT.conf set to the output from previous step

• This process is iterated until all Offset values are zero

• Runned TrackFinder with right offset in OffsetTracker.conf (zOff for all 3 trackers)

* Configuration file used by the Track Finder:

• Runned Analyzer with right offset in OffsetAndCoverage_Analyzer.conf (zOff for 2 CMS chamber and CMS Timing)

• Configuration file used by the Analyzer:

Check for the alignment procedure

This check is made plotting the offset plots of each DUT (Detector under test) wrt the first tracker (g1)

Preliminary results

• Efficiency

• Cluster Size

• Cluster Size vs Current

• Spatial Resolution