GLD ECAL Beam Test at DESY - Plan and outlook - Satoru Uozumi (Shinshu) Jan Japan-Korea Joint Shinshu Univ.

Beam DESY (Feb 25 – Mar ) 26 layers 468 channels Using 1-6 GeV positron beam, evaluate energy resolution, linearity, and position (or spatial) resolution. Have experience of full MPPC readout. - World’s first trial ! Show excellent performance of our detector to the world !

DESY Beam-line ECAL module Movable stage e + 1~6 GeV Trigger counters (3 x 3 cm) Veto counter (with a 2 x 2 cm hole) xyxy Drift chambers (resolution ~ several hundred  m) DESY II Electron Synchrotron e-e- Beam can be defocused up to spot size ~ 5 x 5 cm We can also collimate the beam, but intensity will be lost. Beam rate is order of 10 6 GeV) ~ 300 Hz 3 GeV) with collimated beam Accelerator is always running, and we can have the beam anytime we want!

3 Types of Modules ① WLSF readout 13 layers ② Direct readout 13 layers ③ WLSF readout by extrusion technique 13 layers Beam FR ②①③①①② layers We will examine 3 different combinations of the modules.

Movable stage Can perform precise x-y scan with accuracy of ~1 mm A steel plate (60 x 100 cm) will be mounted on the green arms to put our test modules.

Bias Voltage Control We can set value of the DAC output for each individual MPPC with ~0.02 V step (5 V / 8 bit = 0.02 V / count) Need to prepare a text table which contains DAC counts for all the channels  Need mapping information to convert MPPC number - Strip position – Electronics channel HV supply To Slow-control PC 8 bit DAC (0-5 V) To MPPC 80V -0.96V = V Baseboard single channel

Data & Analysis The data are stored with a binary format on dcache system. Expected raw data size 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 – Using the Marlin framework, we will make root ntuples for quick analysis on the beam test.

Analysis procedure 1.Make ADC distribution for each individual strips. 2.Convert ADC counts to number of fired pixels.  need to know accurate gain of the MPPCs. (Correct for P.D.E. variation with temperature, if necessary) 3.Correct MPPC saturation effect using correction curve and get number of photoelectrons measured on each strip. 4.Divide it with calibration constant (= p.e./MIP), and obtain number of MIPs measured on each strip. 5.Evaluate Energy resolution and Linearity (add responses over all the strips), or evaluate position / spatial resolution

Concern 1 Gain and P.D.E. vary with temperature change 30 o C 25 o C 20 o C 15 o C 10 o C 0 o C -20 o C  V 0 /  T = (56.0 ± 0.1) mV/ o C Can we really correct these effect just by measuring temperature? (for example, device-by-device variation of  V 0 /  T is small enough?)

Concern 2 – correction curve Tsukuba guys are still working to understand this problem … 1600 pixel expected reponse curve 1600 Light input (photoelectrons) Light input (arbitrary) By peak height MPPC signal Light input (arbitrary) 1600 pixels Taken by charge ADC 1600 pixels taken by peak height

Measurement Plan MIP Calibration (once per a couple of days) Since only the positron beam is available, we need to remove all the tungsten plates Energy scan (1-6 GeV, with 0.5 or 1 GeV step) Position scan Test fiber readout module Setup Test direct readout module Test KNU module MPPC dose test withdraw weeks

Beam Test Participants DESY contacts … Benjamin Lutz (Beni), Erika Garutti One room for Feb 25 – Mar 29 (Chang) One room for Feb 25 – Mar 3, Mar

Beam Test DAQ ace Online data monitoring (check pedestal, dead channel, etc) Data analysis software / ntuplization / event display Drift chamber operation and analysis MIP calibration analysis Gain calculation (MPPC and electronics inter-calibration) MPPC response correction Quick result of energy spectra / resolution Temperature / LED monitoring data, correction MPPC dose test

What we will bring to DESY? ECAL module system, LED / temp. monitoring systems Trigger / veto counters Analysis server (CoreDuo 2.3GHz, 1GB RAM, 500GB HD) Laptops with X-window system (Does everyone have it?) Oscilloscopes Testers Source-meter, HPK amp ? Cables, connectors, test boards Tools (drivers, nippers, pliers, cutters, etc….) Request radiative source to DESY Tell me if we need to put more items to the list.

1234 Dec Jan Feb 2007 Delivery of 400 MPPCs MPPC numbering Mass check MPPC baking and soldering megastrip Assembly & source scan ACFA Shipping Feb-14 Beam DESY Feb 25 ~ Mar 29 Test assembly Install LED/Temp. monitor system Prepare shipping MPPC mass check. MPPC soldering Direct-readout megastrip source scan Delivery of 360 MPPCs Fabrication of megastrip layer components Prepare MPPC mass check system KEK Megastrip bench test Fabrication of Frame / light shielding structure Finalize module design MPPC study (response curve) Contact DESY (DC gas, safety issue, etc) Schedule toward the SC-ECAL Beam DESY Establish LED / Temperature monitoring system Analysis code / Event display Prepare Trigger / Veto counters Japan -Korea Settle MPPC Operation voltage

Summary The GLD ECAL beam test will be held at DESY during Feb 25 – Mar The preparation is going well, but we still have lots of things to do. Schedule until the beam test is very tight ! We will have an exciting experience at DESY!

Backups

Questions about KNU module How to put the module ? MPPC Gain monitoring ? Temperature monitoring ? Measurement plan ?

Accomodation plan

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 ECAL module FPCB Scheme of the Readout Electronics

Analog Board ASIC scheme 100nF 10pF Charge Preamplifier :  Low noise :  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 8pF4pF2pF1pF 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 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) 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 fiber LED V bias – V 0 = 1.95 V V bias – V 0 = 2.95 V

Dynamic range (Physics mode) Pedestal (~1123 ADC counts) Saturated MPPC Signal (~20220 ADC counts) ( ) / 226 * 19.1 = 1603 pixels Distance between pededestal – 1p.e. In Calibration mode Ratio of Gains between calib. and physics mode Dynamic range is enough for 1600 pixels !! V bias – V 0 = 2.95 V

Raw binary data LCIO data User analysis modules Database Detector 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

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 !