Reports from DESY

Satoru Uozumi(Staying at DESY during Nov 11 – 25)

Nov-21 GLDCAL Japan-Korea meeting

My tasks @ DESY• Learn about CALICE Analog HCAL (AHCAL) readout elect

ronics– 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, Integrat

ing temperature monitoring etc…

CRC board(in VME crate)

AHCAL module

To DAQ PC

HV supply(up to 100 V)

To Slow-control PC

Baseboard(6 analog boards mounted,

6 board x 18 chan. = 108 chan. )

GLD ECALmodule

FPCB

Scheme of the Readout Electronics

Analog Board ASIC scheme

100nF

10pF

Charge Preamplifier :

Low noise : 1300e- @40ns

Variable gain :

4bits : 0.67 to 10 V/pC

CR-RC² Shaper :

Variable time constant:4 bits (12 to 180ns)

12ns photoelectron measurement (calibration mode)180ns Mip measurement (physics mode)

12kΩ

4kΩ 24pF

12pF

3pF

in

8pF 4pF 2pF 1pF

40kΩ

8-bit

DAC

0-5V

ASIC

Rin =

10kΩ

50Ω

100MΩ 2.4pF

1.2pF

0.6pF

0.3pF

0.1pF

0.2pF

0.4pF

0.8pF

6pF

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 separation2. 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)

Pedestal run(Each with phys.and calib. mode)

……MIP calibration run(Each with phys.and calib. mode)

……LED calibration run

(Each with phys.and calib. mode)

Pedestal – 1 p.e. Peaks Separation (Calibration mode)

Coaxial~ 2 m To HCAL

baseboard

MPPC

Clear fiberLED

Vbias – V0

= 1.95 VVbias – V0

= 2.95 V

Dynamic range (Physics mode)

Pedestal(~1123 ADC counts)

SaturatedMPPC Signal

(~20220 ADC counts)

(20220-1123) / 226 * 19.1= 1603 pixels

Distance betweenpededestal – 1p.e.In Calibration mode

Ratio of Gainsbetween calib. and physics mode

Dynamic range is enoughfor 1600 pixels !!

Vbias – V0

= 2.95 V

Bias Voltage Control

• 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

HV supply

To Slow-control PC

8 bit DAC(0-5 V)

To MPPC80V

-0.96V 80 - 0.96= 79.04 V

Baseboardsingle channel

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

Data & Analysis• The data are stored with a binary format on dcache s

ystem.• 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 a

nalysis framework.– Similar to CDF Run II analysis framework (my feeling)– Need C++ basics– http://Ilcsoft.desy.de/

Raw binary data

LCIO data

User analysis modules

DatabaseDetector geometry,alignment, mapping,etc …

Plots, Ntuples, ….

Analysis scheme

• 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)

Marlin framework

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 ?

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 !

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.

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.