The two running setups: Test Beam  Module 1 ECAL DAQ & VME crate

1. The last 3 months of work on DAQ / data taking / data analysis “the work of: Beni & Marius” The two running setups: Test Beam  Module 1 ECAL DAQ & VME crate 1 LED driven by pulser for gain calibration MIP/LY calibration studies + “some physics” Test Tent  Module 2 HCAL DAQ & VME crate tests on Calibration & Monitoring Board gain studies / VFE & DAQ studies Main HCAL meeting - Erika Garutti

2. Systematic studies on gain determination • Development of a fitting routine capable of fitting 8000 channels (200 for now) finding the SiPM gain with ~1% accuracy • need to understand: influence of electronics on SiPM signal • the bin errors should take into account systematic error to get meaningful Chi2  Systematic between methods < 0.3% (when the fit converges !!!!) Different methods tried: Main HCAL meeting - Erika Garutti

3. Study the influence of the number of peaks found in the gain average Increasing light    Compare average gain obtained with increasing light  2% variation

4. Gain systematic studies G0 = peak1- ped G1 = peak2 – peak1 G2 = peak3-peak2 increasing light  increasing light  increasing light  The determination of peak separation as a function of amount of light is stable at the ~2% level Conclusion: -we have a very powerful tool to perform mass fits but the systematic error is still ~ 2% … good for now! - need to check efficiency Main HCAL meeting - Erika Garutti

5. Test Beam Activities Started from July: - mainly devoted to software development (movable stage integration, multi trigger system, data storage on dcache, online & offline analysis tools…) - DAQ understanding - bug finding - long discharge studies ( Sasha talk) - … and beam data taking ! Some numbers: - ~3 months ~continuous system run - 1 CRC board replacement (BE problems) - 1/2 FE CRC lost (reason unknown) - 2 DAC dead on old VFE (maybe caused by us) - replacement of VFE electronics to new design (2 shift registers) - 0 unexpected losses in DAC settings - replacement of DAQ computer (~factor 2 gain in DAQ rate, ~25Hz) Main HCAL meeting - Erika Garutti

6. MIP calibration Stage scan in front of 3 GeV beam (+2 mm steel) Long Discharge SiPM MIP-ped separation possible Noise (>1/2 MIP) > 100 ev/hcal Worse MIP-ped separation AMIP ~ 240 ADC ch. Noise (>1/2 MIP) ~ 7 ev/hcal Good MIP-ped separation AMIP ~ 350 ADC ch. Noise (>1/2 MIP) ~ 0.5 ev/hcal - Pedestal trig - Beam trig ADC ch. Main HCAL meeting - Erika Garutti

7. Calibration reproducibility • 4 runs taken in consecutive days • Check MIP reproducibility for 15 ch. • RMS ~2% (systematic error on MIP calib.) +2% - 2% Main HCAL meeting - Erika Garutti

8. Second Particle in the Beam Tile in the beam Correlation • 1 5x5 cm counter installed at the finger cross position ~2.5 m before the module • Idea: use the spectrum in the PM to “clean” second particles in the MIP • The second “bump” in the PM is not directly correlated to that in SiPM • 2,5 m of air in between • MIP spectrum cannot be improved for fit PM , 2.5 m before the Module Main HCAL meeting - Erika Garutti

9. Calibration Results MIP average (for 170 ch.): 395 ADC ch +/- 18% 170 ch. Calibrated 4-7 ch. “Dead” ~10 ch. MIP non visible  LD Main HCAL meeting - Erika Garutti

10. Tile Uniformity Check with Beam tile 1 tile 2 • Beam scan on tile surface in • 1mm steps • MIP amplitude meas. at each step max variation ~10%, RMS = 4.7% (remember 2% reproducibility !!) • Integrated energy deposited above ½ MIP at each step gives an idea of the beam profile Problems: • The beam is too broad for a precise measurement of edge eff. Main HCAL meeting - Erika Garutti

11. Noise @ ½ MIP Threshold Noise = # events > ½ MIP / tot events * 8000 channels (= hcal) 170 channels measured: 140 < 20 ev/hcal 80 < 5 ev/hcal High noise + LD (~60) Long discharge (~30) zoom 5 Noise [#ev./hcal] Main HCAL meeting - Erika Garutti

12. Voltage Correction for LD Delta V = ITEP - reduced • Idea: • Recover LD SiPM by lowering bias V • Value of “reduced” V set according to • Vladimir direct measurements of SiPM • Corrected SiPM shifted to lower gain • 67 ch. meas. (18 with LD @ ITEP V) • ch. have too low gain  no MIP • 2 ch. still with LD Main HCAL meeting - Erika Garutti

13. Next Step: LY Calibration  Goal: DLY ~ 1% •  all data collected and under anaysis •  first look at the systematic uncertainty: • systematic error on pedestals (2 diff. triggers, 2 diff. modes) < 0.5% • Electronic Intercalibration • same LED light in both modes: max LED light 10 MIPs (calibration mode) • gaussian shape of light attainable above 5 MIPs • AMP / RMS ~ 10 • with gaussian shape: dAMP < 0.1% • Gain (calibration mode)  systematic studies from Beni (~1%) Main HCAL meeting - Erika Garutti

14. Next Step: LY Calibration • MIP (physics mode) • “preliminary” fit: • gauss + landau • <d MIP> for 170 channels ~ 1.5% with RMS = 1% • right fit procedure is a open question large systematic error ?% at the moment with non-optimized fit • More work is needed to reach the 1% goal … but we are not too far  Main HCAL meeting - Erika Garutti

15. Outlook @ the beam • Our beam time for this year is (almost) over • Much more beam data already collected  to be analyzed - LY calibration (@ nominal and reduced bias) - shower max scan  check correction of SiPM non-linearity - 1X0 data with up to 3 MIPs visible  improve on “LY” calibration • Data analysis completely based on .bin DAQ file  LCIO conversion / check / development of analysis tools @ the tent • Long term run with 4 ½ modules - cosmic calibration - commissioning of LED monitoring system - long term stability studies • Next month: Integration of the tail catcher in the DAQ + test beam Main HCAL meeting - Erika Garutti