D. Silvermyr, ORNL1 Test Beam - Outline FNAL/Test Beam I (Nov 2005) Results overview from Test Beam I Test Beam II – SPS and PS (Sep – Oct 2007) Current status, future plans

D. Silvermyr, ORNL2 FNAL Test by Numbers We ran with ~(3),4, 8, 16, 33, 66 GeV/c beams. Mixed beams. Electron (Cherenkov) trigger, with variable pressure. We could id. electrons (offline) from 3 to 33 GeV/c. Spill length: ~4 seconds every 2 minutes. Rates: can get ~400 counts / spill at ~4 GeV/c, +20k at 16 GeV/c. Beam size: a few cm squared. Momentum bite/spread: approx 1% variation of the momentum.

D. Silvermyr, ORNL3 Modules & Electronics 16 modules, each with 2x2 towers. 2 Front-End Cards; 32 chan. * hi/low gain for each 1 DCS/RCU Communication via optical fiber 3 independent DAQ streams, (ALICE, MTEST, CAMAC) aligned offline spill-by-spill.

D. Silvermyr, ORNL4 Performance / Results Section I) Calibrations using LED pulser.

D. Silvermyr, ORNL5 LED pulses (short and long shaping time) Event Display; ADC vs Time-Sample #. Half the detector (1st FEC): shorter shaping time, and set to approx. 60% of the gain, relative to the 2 nd FEC. [default PHOS settings] Tower-by-tower diff.:  Calibrations are important. FEC 13 FEC 14

D. Silvermyr, ORNL6 LED: Amplitude vs Voltage (gain) High gain (16*Low gain) Low gain Calibrate the gains of the APDs by varying the bias voltage and see how the rec. amplitude of the LED pulse changes. Obtain gain factors of about 35 from 50 V to 380 V. [We also compare the electron peaks in the real data tower-by-tower; obtain similar light yield as PHOS: 4.4 p.e./MeV]

D. Silvermyr, ORNL7 LED: Amplitude vs The average reduction was ~ 2 % per deg C (or 1% per deg F) Measured how the signal amplitude for LED/pulser events was reduced for higher temperatures. Start of winter at FNAL Temp. stability test

D. Silvermyr, ORNL8 Performance / Results Section II) Real data We had all files at the PDSF Cluster / LBL for collaborative analysis. (copy also at WSU). Results are included in the Technical Design Report (CERN-LHC), and the CDR document for DOE.

D. Silvermyr, ORNL9 First Signals - with 120 GeV (protons) Short shaping time Long shaping time (PHOS) Note difference in x (sample) scale. Every bin is 100 ns. We extract signal amplitudes (ADC) and pedestals from fits to shape spectra. With channels/GeV calibration => measured energy.

D. Silvermyr, ORNL10 Energy Resolution at 16 GeV (very preliminary: ~online) All triggers Selected electrons Use electron peak (edge) for tower-by-tower calibration and then patch sum (3x3) over several runs to get the energy resolution.

D. Silvermyr, ORNL11 MIPs - hadrons Zoom in on MIP region: In addition to electron peak (here 8 GeV/c), MIP peak around 250 MeV/c. Also used for calibration.

D. Silvermyr, ORNL12 Energy Resolution - All Energies Included ~all runs (all towers and all energies). See significant variation with time/temperature. Calibrated performance exceeds stated requirements.

D. Silvermyr, ORNL13 MIP vs Energy MIP (most probable value) vs beam momentum, and with fit by function on mean energy loss in 12.32cm of Sc (77*0.16cm). Found sample factor ~9.

D. Silvermyr, ORNL14 Result: Energy dependence of position resolutions Dispersion cut (<0.15) does not make a significant difference for the resolution. A linear fit to the E -1/2 dependence of position resolutions gives 1.5 [mm] + 5.3*E -1/2. Short shaping * E -1/2

D. Silvermyr, ORNL15 Section III) Test Beam CERN

D. Silvermyr, ORNL16 Test Beam (II) ) With ~final modules/design – size changes since ) With ~final electronics chain: final FEE cards (rather than ad hoc modified, PHOS prototype cards), long flat cables, modified transition cards, new LED system etc.. Investigate stability (calibrations/LED running, table movements, temperature changes, position and energy scans..) Starting with a period at SPS North Area (H6, shared with ALICE ZDC), followed by time at PS (T10). Around 30 persons signed up to participate at different times! Other goals: Exercise slow controls (HV, ELMB,..), online monitoring and calibration + write more ‘official’ raw data files that can be fed into offline chain for software exercises as part of preparations for real data running. This 2 nd Test Beam is also another good opportunity for new/interested collaborators to get familiar with the device, and analysis.

D. Silvermyr, ORNL17 CERN Test by Numbers We have run with ~(5),10, 20, 40, 60, 80, 100 GeV/c beams at SPS. Electron beams.. Spill length: ~4.8 seconds with a 10 second spill gap. Rates: can get ~1500 counts / spill at ~80 GeV/c, significantly lower for low momenta. Beam size: ~1 cm squared. Momentum bite/spread: approx 1% RMS of the momentum, i.e. significant at high momenta. For Sep run period we had collimators rather open; will tighten this for run period from Oct 4 (beam back around 10.35; steering before lunch). Larger energy range, more spills, more electrons, smaller beam spot than at FNAL. Lower energy range to be covered at PS in 2 nd half of Oct. Current SPS period lasts until Oct 10 (morning).

D. Silvermyr, ORNL18 LED pulses (2007) Event Display; ADC vs Time-Sample #. More powerful LED signals than in 2005 TB. Tower-by-tower diff.:  Calibrations are still important.. FEC 5 FEC 6

D. Silvermyr, ORNL19 ELMB (2007) DCS monitoring; Temp. (C) vs Time #. Use official ELMB chain (MB, cables, software); also for HV/ISEG control. Variations smaller than at FNAL, and we do energy scans etc more quickly now, but may still need to correct for temperature changes.

D. Silvermyr, ORNL20 Beam event (2007) Event Display; ADC vs Time-Sample #. 80 GeV run; have runs from GeV/c. (not analyzed all in detail though yet..) FEC 5 FEC 6

D. Silvermyr, ORNL21 Example energy distribution (2007) 3x3 patch sum With preliminary calibrations. Note difference with 2005 TestBeam: ~Not so many MIPs, mostly electrons..

D. Silvermyr, ORNL22 LED and physics triggers (2007) In the same run, we now have both LED and physics events LED triggers fire ~all channels in the event, and the peaks also occur ~1 micro- sec later than with physics triggers (now at the testbeam).

D. Silvermyr, ORNL23 Resolution vs Energy (2007) With many caveats.. Examples: 1) Beam momentum spread not subtracted 2) Preliminary calibrations done for each energy individually. …etc… Several effects can bring values both up or down, so pls don’t really look at the fit values. I think we can say though that things look reasonable and promising already after just a few days of looking at the data.

D. Silvermyr, ORNL24 Summary We had a successful beam test in 2005 with preliminary electronics and module prototypes. Most everything worked well. Ongoing testbeam in 2007, with almost final design also looks good (better?) so far.. We have shown that we have a working system that exceeds the stated requirements. Will continue with analysis; also study position resolution (with MWPCs in setup), shower shapes and ‘tilted’ modules configurations. Analysis results will also be used to improve future MC studies. Detailed NIM write-up after 2 nd Test Beam is done/analyzed.

D. Silvermyr, ORNL25 Backup

D. Silvermyr, ORNL26 ALICE EMCal Testbeam (I) – FNAL Nov 2005 One week setup + ~two weeks as primary users at FNAL testbeam (MT6) ending Mon Nov 28. A total of 18 persons from 8 institutions participated in the setup, data collection and analysis! [stays at FNAL from a few days to a few weeks each] Houston: A. Mairani, B. Mayes LBL : P. Jacobs, A. Mischke, M. van Leeuwen, J. Putschke LLNL: A. Enokizono, J. Klay Purdue: L. Molnar ORNL: T. Awes, D. Silvermyr UCLA: S. Trentalange WSU: T. Cormier, M. Elnimr, A. Pavlinov, V. Petrov + Frascati (I): N. Bianchi, P. Di Nezza.

D. Silvermyr, ORNL27 Resolution and dispersion studies - 8 GeV Run1191, xpos = (short shaping) Electron cut: 6.0<energy deposit<10.0 GeV 3x3 sampling, log-weight factor = 4.5

D. Silvermyr, ORNL28 Fitting Studied fit parameters, and stability. The time-squence is fitted with a gamma function+pedestal. The functions has four parameters: amplitude A : what comes out as channel ADC pedestal p: the pedestal on which the shape sits power n: the power in the exponential of the gamma function decay constant tau: the rate of decay in the tail time t0: the peak-time (or related to it)

D. Silvermyr, ORNL29 Comparing with PHENIX EMCal beamtest ALICE (prel.)

D. Silvermyr, ORNL30 Position Resolution Short shaper Long shaper Quite similar values observed for the two shaping times.