Difference between revisions of "GEM"
(→Analysis of Pedestal, runs taken until April 22, 2010 (Francesco)) |
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=== Analysis of Pedestal, runs taken until April 22, 2010 (Francesco) === | === Analysis of Pedestal, runs taken until April 22, 2010 (Francesco) === | ||
| − | Analyzed all the run listed in the Run | + | Analyzed all the run listed in the Run List, until run 27402. |
| − | The pattern is stable for UVA GEM both chambers, while looks having two different "states" in the INFN chambers. | + | The pattern is stable for UVA GEM both chambers, while it looks having two different "states" in the INFN chambers. |
Within one hour the pedestals looks very stable (run 23355-23358) | Within one hour the pedestals looks very stable (run 23355-23358) | ||
| − | Pedestals calculated from a pedestal-run (27336) have no | + | Pedestals calculated from a pedestal-run (27336) have no significant differences with respect to the values extracted from an on-beam run, but of course the noise is smaller. |
| − | The pedestals show a "common-mode" shift on a 24-hour time-scale (comparison between | + | The pedestals show a "common-mode" shift on a 24-hour time-scale (comparison between runs 27355-27358 and run 27402) |
[[Image:run27336noise.pdf]] | [[Image:run27336noise.pdf]] | ||
Revision as of 22:52, 21 April 2010
General GEM Information
- NIM Papers
- PDG Accelerator Detector Review (See Section 28.6.3)
- Super BigBite CDR
GEM Detectors for PREX
Configuration
The GEMs were mounted in an XY XY XY XY configuation on April 14. Our best guess at positions (from Dustin) in the rotated coordinate system are:
| Detector | Orientation | z (m) |
| Bottom UVA | XY | 1.15 |
| Top UVA | XY | 1.15 |
| Bottom INFN | XY | 1.4 |
| Top INFN | XY | 1.4 |
Chambers are placed orthogonal to the z axis.
HV Adjustment
Individual chamber HV is controlled through a CAEN N1471 NIM module. It can be remotely controled through minicom on ahut. The channel mapping is
http://www.jlab.org/~adaq/halog/html/1004_archive/100414225720.html
| Channel | Cable | Detector |
| 0 | 7 | Top UVA |
| 1 | 8 | Bottom UVA |
| 2 | FPP7 | Top INFN |
| 3 | FPP6 | Bottom INFN |
Gas configuration
The gas is presently a 80-20 Argon/CO2 mix (or 70/30?).
Replaying Data and Software
Replaying data can be done on any of the adaq machines. Simply do
goprex analyzer prex_gem_L.C
and enter in the run number and number of events you would like to analyze. The database for the GEMs is in the $DB_DIR directory. This replay uses the TreeSearch-GEM library for GEM decoding, clustering, and tracking maintained by Ole Hansen.
Replayed files go in the rootfiles directory and are named
prex_gem_L_xxxxx.root
Run List
Work to Do/Main issues
- HV Scan
- Pedestal analysis (Francesco Cusanno)
- Stability
- Event-by-event corrections algorithm
- Higher order event-by-event corrections
- HV/Rate dependence
- Pedestal value/widths to find bad channels
- Cluster Analysis
- Multiple cluster propagation across planes
- Clusters energy association between planes, noise evaluation
- Position Resolution (Ozgur Ates)
- Evaluate plane resolution
- Different ways to utilize energy information to maximize resolution(?)
- Efficiency/Gain Analysis (Kiad)
- Evaluate hit efficiency vs. ADC cuts
- Efficiency, gain vs. strip
- Efficiency, gain vs. HV
- Gain differences in readout planes
- Tracking (Ole + Kiad)
- Quantify X-Y hit association techniques
- Bad Channels Handling (Ole)
- List to ignore in software
- How they affect clustering/energy weighting
Commissioning Meeting Summary
Analysis status, April 19, 2010
Listed projects that need to be finished for GEM tracking and divided among students/postdocs/staff.
Seamus' HALOG post on status:
http://www.jlab.org/~adaq/halog/html/1004_archive/100416175501.html
Analysis of Pedestal, runs taken until April 22, 2010 (Francesco)
Analyzed all the run listed in the Run List, until run 27402.
The pattern is stable for UVA GEM both chambers, while it looks having two different "states" in the INFN chambers. Within one hour the pedestals looks very stable (run 23355-23358) Pedestals calculated from a pedestal-run (27336) have no significant differences with respect to the values extracted from an on-beam run, but of course the noise is smaller. The pedestals show a "common-mode" shift on a 24-hour time-scale (comparison between runs 27355-27358 and run 27402)
