FCAL R

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FCAL RD in Minsk GroupSensors and Electronics
Presented by Igor Emeliantchik
FCAL Collaboration Meeting_at_ MPI Munich October
17, 2006, Munich, Germany
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Current Spectrometric Setup

• NIM CAMAC
• LeCroy 2249W ADC
• Tetrode preamp

90Sr
Paraffin collimator
Diamond
Scintillator
Noise with Minsk diamond 580e- with
Freiburg diamond 750e-
PMT
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Monocrystalline Diamond Detector
Contact device is made for measurement of
non-packaged diamond detectors
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CCD Measurement Difficulties
Background
Signal

• Background is much bigger than signal
• Two possible reasons
• Low efficiency of trigger system due to small
  area of the diamond.
• Non-uniformity of the diamond dead areas give
  no signal.

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Response dependence on the dose
absorbed,measured with oscilloscope
Averaged amplitude of response to the whole
?-spectrum of 90Sr was measured with digital
oscilloscope at each dose point. Detector
behavior seems to demonstrate classical
pumping effect, no polarisation.
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Test of trigger efficiency measurement of
natural diamond of the same area
Signal
Background
Trigger efficiency seems to be not the cause of
large background in the case of syntethic
monocrystalline diamond
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CCD versus dosemeasured in standard way
The trendline confirms the previous measurement
made with oscilloscope. No polarization, just
pumping
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Next Steps
New samples, not yet measured
1. Experimenting with parameters of thermobaric
procedure.
Dependence of N-N and Me-N centers formation on
the temperature and duration of annealing,
measurement with optical methods
2. Comparison of Fe-Ni and Fe-Co grown diamonds
and choosing the best.
Nikel and cobalt have different solubilities in
diamond and form different types of defects.
3. Detailed measurement of stability and dose
dependent behavior.
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Freiburg CVD DiamondsMeasurement of Charge
Collection Distance
Desy7, before irradiation
Desy7, irradiated with 1 Gy
Fitting with 2 gausses, left one represents the
background, right one the signal
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CDD Dependence on the Time and Dose, sample Desy7
Strong polarisation effects can explain this
behavior
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CDD Dependence on the Time and Dose, sample FAP7.3
Polarization effects are expressed even stronger
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DESY7 with Replaced MetallizationTi-Ag with
proper annealing for titanium carbidization
Dose related behavior hadnt changed, but the
value of CCD before irradiation increased
twofold (CCD 32?m with old metallization, CCD
65?m with new metallization).
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Electronics for a segment of BeamCal detector
prototype based on GaAs sensors

• GaAs detectors provide
• Strong signal
• High radiation hardness GaAs/Si ? 10
• Small leakage currents (no refrigeration)

Sensor segment layout
Sensor specifications
Thickness 500mcm
MIP charge 30000e
Bias voltage 100V
Pad number 87
The sensor, output connectors and a power supply
connector are mounted on a common PCB
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AS01PDA ASIC meet the detector requirements
AS01PDA main parameters
Channel structure Preamplifier - Shaper - 50 Ohm Driver
Shaper peaking time 90ns
Maximum differential gain 9mV/fC
ENC, e 100014.1e/pF
Shaper output /-1.5V
Power consumption 18mW
Package SOP16
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AS01PDA block diagram
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AS01PDA on the small PCB and eight channels flat
bar PCB
Main unit of the FEE prototype
One flat bar of the FEE prototype
The GaAs prototype electronics will consist of
eleven PCB flat bars (87 channels)
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FEE prototype measurement results
Gain and waveform versus detector capacitance in
response to 10fC input charge
Linearity at different power supply voltages
Linearity measurements done by Krzysztof Oliwa
and Wojciech Wierba
The IC was earlier tested with Tomsk GaAs
detectors (1cm x 1cm) and shown good results
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Schedule of assembling of GaAs calorimeter
segment prototype

• End of October - 87 channels of the FEE will be
  done
• November GaAs sensors will be done

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Conclusions
1. First measurements of Minsk monocrystalline
diamond detector are performed. 2. New
metallization for CVD diamonds is tested the
first sample with new metallization works
better than with old one. 3. First channel of
redout electronics for GaAs calorimeter segment
prototype is assembled and tested the work is
going on within the schedule.