CERN SPS and PS Tests 2007 Goals: Show we have a working EMCal system That meets specifications! Quantify the performance characteristics of production EMCal Energy resolution Position resolution Electron/hadron discrimination by shower shape Time measurement? Dependence of all of above on position of incidence - uniformity Demonstrate we have a working gain monitoring system (LED) Sufficient signal to be useful Stable and reproducible LED signal in each tower Does LED variation track gain variations? (e.g.due to temperature) July 17,2008 ALICE EMCal Beam test

CERN SPS and PS Tests 2007 Goals: Calibration with Cosmics Quantify how well it will work by comparison to electron calibration Determine best procedure Trigger - data rate Zero suppression? (data volume problem) Analysis method - single tower, isolation cut, cluster? Data set to develop and test analysis software Optimal E-signal extraction (speed vs performance) Gain variation corrections using LED or Temperature data Clustering Shower identification cuts Refine simulated data parameters (noise, shower tracking cuts) Exercise EMCal “system” in ALICE PVSS control DATE data acquisition Storage and access to “large” data sets in CASTOR & AliEn Batch production of ESD Analyisis within ALICE offline framework July 17,2008 ALICE EMCal Beam test

EMCal Test Setup - CERN 2007 Z=0 configuration Pre-Production Modules (1/3 size “strip modules”) 4x4 modules or 8x8 towers Readout with production version of all components (FEE v1.1e) (except IPCB and GTL bus, no TRU) Readout via ALICE DAQ - DATE, stored in CASTOR (eventually). ~3.5m Z=0 configuration July 17,2008 ALICE EMCal Beam test

EMCal Test Setup - CERN 2007 Large Z configuration July 17,2008 ALICE EMCal Beam test

EMCal Test Setup - CERN 2007 Phi-Tilt configurations - 3,6,9o July 17,2008 ALICE EMCal Beam test

Strip Module Internal Components Production versions of internal components: APD+Preamplifier, Transition Card, LED fiber distribution, Temperature sensors, molex cables 2007 Prototype Modules Transition Card Temperature measurements inside strip modules July 17,2008 ALICE EMCal Beam test

EMCal LED Gain Monitoring System LED system needed for gain adjustment and gain monitoring. LED system used for FNAL tests was N.G. One fiber per module (shown) excites WLS bundle - low efficiency. 12 modules (fibers) per strip module fed by one fiber from remote LED to strip module. Prototype LED driver used in test beam. July 17,2008 ALICE EMCal Beam test

LED Gain Monitoring 8x8 towers FADC time spectra LED Driver with fiber distribution gives ~30 GeV equivalent. Ideally, would like LED @~13 GeV to be at upper range of High Gain -> good signal on high and low gain. LED system gives enough light! July 17,2008 ALICE EMCal Beam test

Understanding Gain(T) Corrections SPS1 SPS2 PS Temperature measurements inside each strip module (day/night variations clearly seen) Does the LED system track these Temperature variations? Gain variation ~2% / oC 1o C July 17,2008 ALICE EMCal Beam test

SPS Measurements Tertiary beam. By choice of secondary target and absorber obtained very pure electron or hadron beam Simple scintillator trigger - no need for cerenkov for particle ID MWPC tracking: 3MWPC (Grenoble) + 1 MWPC (CERN) EMCal position resolution and uniformity (multiple planes allow to determine tracking residuals to extract EMCal only resolution) Took electron data at 5,10,20,40,60,80 and 100 GeV/c Took hadron data at 20,40,60,80 and 100 GeV/c Scanned through all towers with 80 GeV/c electrons for relative gain calibration - twice (check reproducibility) Scanned through most towers with 80 GeV/c hadrons to compare MIP vs electron calibration Position scans to check uniformity Geometry: Z=0 and large Z geometries, and 6 and 9 degrees phi incidence July 17,2008 ALICE EMCal Beam test

Electron Event at SPS FEC 5 FEC 6 Event Display; ADC vs Time-Sample #. 80 GeV electron event Relative gain calibration: position scan with 80 GeV/c electrons in each tower. July 17,2008 ALICE EMCal Beam test

Example energy distributions 3x3 tower sums With preliminary SPS calibrations (by Marco, Aleksei). In general, ~20% more light - as expected by increased sampling. Note the “clean” e spectra! July 17,2008 ALICE EMCal Beam test

Resolution vs Energy Momentum scans: 5,10,20,40,60,80 and 100 GeV/c electrons at several central locations and across boundaries. Preliminary energy resolution better than with first prototypes - better sampling July 17,2008 ALICE EMCal Beam test

PS Setup July 17,2008 ALICE EMCal Beam test

PS Measurements Secondary beam. Beam trigger based on Scintillators Cerenkov counter to tag electrons, electron trigger Muon veto paddle to tag muons for beam triggers MWPC tracking: 2MWPC (Grenoble) Took electron data at 0.5, 1,2,3,5 and 6.5 GeV/c Took beam data at 0.5, 1,2,3,5 and 6.5 GeV/c GeV/c Scanned through all towers (twice) with 3 GeV/c electrons for relative gain calibration. Scanned through all towers with 3 GeV/c hadrons to compare MIP vs electron calibration Position scans to check uniformity Geometry: Z=0 and large Z geometries, and 3, 6 and 9 degrees phi incidence; laid strip module on side and scanned with hadrons through “top” to check as a possible cosmics configuration July 17,2008 ALICE EMCal Beam test

Cosmics calibration test at CERN Some Cosmics data was been taken: Data with: Testbeam gains Matched gains Maximum bias Different scint. trigger conditions Okay - but more difficult than sim. July 17,2008 ALICE EMCal Beam test

Precision of “Cosmics” calibration FNAL test beam results: After calibration of towers with electron beam (16 GeV/c) position of “MIP” peak for each tower observed to vary by less than +/-1.5%. We need to demonstrate that we can do this with a cosmic trigger setup for the initial calibration of the SMs. Cosmics result - Sebastien, Aleksei MIP peak MIP peak variation 1.5% From Aleksei Pavlinov July 17,2008 ALICE EMCal Beam test

Analysis We have a very large data set More than 1100 runs, 525 Gbytes of data from SPS+PS A similarly large amount from the Cosmics setup The raw data volume is sufficiently large that the only copy is in CERN central storage. Early attempts (by David) to process the data via AliEn were very frustrating - (staging delays causing processes to abort) The raw->ESD processing task is sufficiently large that the ALICE offline group has volunteered that they will manage the offline production for us - to David’s delight! We likely will want to repeat this to test “improvements” in the raw data peak extraction See David’s nice documentation at http://dsilverm.web.cern.ch/dsilverm/testbeam07 for details for analysis: Run logbooks and Elogs for SPS, PS, and cosmics periods Pointers to analysis code to begin analysis July 17,2008 ALICE EMCal Beam test

Analysis - Status: “Disorganized” We had/have a large number of people interested to analyze data (Grenoble, Nantes, Catania, Frascati, CERN, WSU, Houston, Tennessee), but many without EMCal experience. Analysis task list (~NIM figures) with volunteers We had semi-regular analysis meetings for a short while after the beam test, but they stopped with results being reported in the bi-weekly offline meeting Useful, but lost focus and direction Three main General tasks needed to before final analyses: Gain(Temperature) correction result and tools Done - Rachid, David, (Aleksei on his own) Tracking data with MWPCs (for all position studies) Almost done - Josh, Dilan, David Final Raw->ESD production with optmized signal peak fitting Soon - Raphaelle, ALICE Offline group Need to resume regular dedicated Testbeam analysis meetings… Ultimate goals: Confirm Cosmics calibration procedure NIM paper July 17,2008 ALICE EMCal Beam test

Calibration , 80 GeV, SPS1 – 3 xlog:ylog distribution of the cluster Position scan: Beam distribution for various runs This and following Slides from Aleksei:

Calibration , 80 GeV, SPS1 – 4 Best and worst runs for resolution

Calibration , 80 GeV, SPS1 – 5 Summary picture – E(rec) vs #runs Resolution varies from 1.6% to 2.4% Reconstructed beam energy has RMS ~1% Set of calibration coefficients are using for reconstruction

60 GeV - 1 1. Mean value of beam energy is almost the same as “ideal” one (only reconstruction here – no calibration)‏

5GEV - 1 Mean value of beam energy is the same as “ideal” one <1%

5GEV – 2 Resolution varies from 6.8% to 7.6% Reconstructed beam energy has RMS ~1.%