Reports from DESY

1. Reports from DESY Satoru Uozumi (Staying at DESY during Nov 11 – 25) Nov-21 GLDCAL Japan-Korea meeting

2. My tasks @ DESY • Learn about CALICE Analog HCAL (AHCAL) readout electronics • Actual operation of the DAQ system • Confirm it has satisfactory performance for the GLD ECAL beam test • Gain of ASIC amp • Pedestal – 1 p.e. peaks separation with the MPPC • Bias voltage setting for individual MPPC • Dynamic range of the Amp and ADC • Separation of noise and MIP peak • Data analysis • Basic analysis scheme with the CALICE analysis framework • Learn something from actual AHCAL analysis • Other stuffs • Movable stage, LED monitor, Drift chambers, trigger counters, Integrating temperature monitoring etc…

3. Scheme of the Readout Electronics Baseboard (6 analog boards mounted, 6 board x 18 chan. = 108 chan. ) To DAQ PC FPCB CRC board (in VME crate) AHCAL module GLD ECAL module To Slow-control PC HV supply (up to 100 V)

4. Analog Board ASIC scheme 40kΩ 100MΩ 0.1pF ASIC 2.4pF 8-bit DAC 0-5V 0.2pF 1.2pF 0.4pF 0.6pF 0.8pF 0.3pF in 12kΩ 4kΩ 24pF Rin = 10kΩ 10pF 50Ω 12pF 8pF 4pF 2pF 1pF 6pF 100nF 3pF • CR-RC² Shaper : • Variable time constant:4 bits (12 to 180ns) 12ns  photoelectron measurement (calibration mode) 180ns  Mip measurement (physics mode) • Charge Preamplifier : • Low noise : 1300e- @40ns • Variable gain : 4bits : 0.67 to 10 V/pC

5. Gain of the ASIC Amp • We have 2 different modes under current setting : 1. Physics mode … lower gain, large dynamic range Can not see the ped – 1 p.e. peaks separation 2. Calibration mode … high gain (~x20 of physics mode) Can see the peak separation • We can choose the mode for each individual run. • Inter-calibration of the gain between these 2 modes is necessary. Will be performed in MIP calibration run? • We can choose some other gains if we request, though I think current setting for AHCAL is useful enough. MIP calibration run (Each with phys. and calib. mode) Pedestal run (Each with phys. and calib. mode) Beam run (Physics mode) LED calibration run (Each with phys. and calib. mode) MIP calibration run (Each with phys. and calib. mode) Pedestal run (Each with phys. and calib. mode) …… ……

6. Pedestal – 1 p.e. Peaks Separation (Calibration mode) Coaxial ~ 2 m LED Clear fiber To HCAL baseboard MPPC Vbias – V0 = 1.95 V Vbias – V0 = 2.95 V

7. Dynamic range (Physics mode) Vbias – V0 = 2.95 V (20220-1123) / 226 * 19.1 = 1603 pixels Pedestal (~1123 ADC counts) Distance between pededestal – 1p.e. In Calibration mode Saturated MPPC Signal (~20220 ADC counts) Ratio of Gains between calib. and physics mode Dynamic range is enough for 1600 pixels !!

8. Bias Voltage Control Baseboard single channel • We can set value of the DAC output for each individual channel with ~0.02 V step (5 V / 8 bit = 5 V / 256 count = 0.02 V / count) • Need to prepare a text table which contain DAC counts for all the channels 8 bit DAC (0-5 V) 80 - 0.96 = 79.04 V -0.96V To Slow-control PC 80V HV supply To MPPC

9. Movable stage Can be controlled from Slow-control PC with user-friendly GUI. Specify position with 0.1 mm step

10. Data & Analysis • The data are stored with a binary format on dcache system. • Expected raw data size (with 6 baseboards) is about 5 kB / events. (very rough estimate, with +- 50% of uncertainty) • We can access to the binary data using the Marlin analysis framework. • Similar to CDF Run II analysis framework (my feeling) • Need C++ basics • http://Ilcsoft.desy.de/

11. Analysis scheme Raw binary data • We need to request for database entry for our ECAL module • Need to prepare codes for detector geometry, mapping. • We also need to give a “Prefix” of our detector which is used as identifier in the analysis module (like AHCAL) I propose “SCECAL” (SCintillator ECAL) for the prefix. (e.g. our calibration constants will be named SCECAL_CALIB on database) Database Detector geometry, alignment, mapping, etc … LCIO data User analysis modules Marlin framework Plots, Ntuples, ….

12. My tasks @ DESY • Learn about AHCAL readout electronics • Actual operation of the DAQ system – Done • Confirm it has enough performance for the GLD ECAL beamtest – Done • Peaks separation with the MPPC – Done • Gain of ASIC – Done • Bias voltage control for individual MPPC – Done • Dynamic range – Done • Separation of Noise and MIP peak – may be tested in this week • Data analysis • Basic analysis scheme with the CALICE analysis framework - Done • Learn something from actual AHCAL analysis - ongoing • Other stuffs • Movable stage - Done • Drift chambers – readout modules are now at CERN should be easy to operate • Trigger counters – Should be no problem (need a beam to check) • LED monitor - Difficult to integrate AHCAL system into GLD ECAL module • Integrate temperature monitoring into DAQ PC • Any Other ?

13. Experts @ DESY • Felix ... The head • Erika ... Expert of everything in CALICE group • Beni … Expert of the AHCAL DAQ electronics and analysis contact person of the GLDCAL beam test at DESY • Sebastian … Expert of software package • Niels … Expert of AHCAL analysis code • Nicola … Expert of SiPM / MPPC • Alexandra … Expert of SiPM / MPPC They are really nice, and of course, very reliable !

14. Summary • The AHCAL electronics and DAQ system have good performance satisfactory for the GLD ECAL beam test. (There is still a concern about noise on FPCB, though) • Moreover we have many reliable experts at DESY . • Any other stuff at DESY (movable stage, triggers, drift chambers…) are OK. • People who will attend to the beam test may need to be familiar with the caliceMarlin analysis framework.

15. Plan for this week • AHCAL people may perform a test with positron beams. (test of forward-backward asymmetry of the AHCAL module) Attending this test would be a good exercise with the actual beam. • I am requested to give a talk at DESY HCAL meeting in Thursday. I will give : • 10 minutes talk • brief introduction of GLD ECAL beam test • My task and achievement at DESY • Lots of appreciation • Then as long as time permits, I will learn about the actual analysis of AHCAL beam test data.