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FCAL R&D in Minsk Group:Sensors and Electronics
NC PHEP BSU, Minsk K.Afanaciev V.Gilewsky I.Emeliantchik A.Litomin V.Shevtsov A.Solin
FCAL Collaboration Meeting@ MPI Munich
October 17, 2006, Munich, Germany
Presented by Igor Emeliantchik
Current Spectrometric Setup
• NIM + CAMAC
• LeCroy 2249W ADC
• “Tetrode” preamp
Noise:
with Minsk diamond – 580e-
with Freiburg diamond – 750e-
PMT
90Sr
Paraffincollimator
Diamond
Scintillator
Monocrystalline Diamond Detector
Contact device is made for measurement of non-packaged diamond detectors
CCD Measurement Difficulties
Background is much bigger than signal
Two possible reasons:1. Low efficiency of trigger system due to small area of the diamond.2. Non-uniformity of the diamond – “dead” areas give no signal.
Signal
Background
Response dependence on the dose absorbed,measured with oscilloscope
Amplitude versus Dose
0,00100,00200,00300,00400,00500,00600,00700,00800,00
0 0,5 1 1,5 2
Dose, Gy
Am
ol,
mV
Averaged amplitude of response to the whole -spectrum of 90Srwas measured with digital oscilloscope at each dose point.
Detector behavior seems to demonstrate classical pumpingeffect, no polarisation.
Test of trigger efficiency: measurement of natural diamond of the same area
SignalBackground
Trigger efficiency seems to be not the cause of large background in the case of syntethic monocrystalline diamond
CCD versus dosemeasured in standard way
#1 CCD versus Dose
020406080
0 0,1 0,2 0,3 0,4 0,5 0,6
Dose, Gy
CC
D,
mcm
The trendline confirms the previous measurement made with oscilloscope.
No polarization, just pumping
Next Steps
New samples, not yet measured
1. Experimenting with parameters of thermobaric procedure.
2. Comparison of Fe-Ni and Fe-Co grown diamonds and choosing the best.
3. Detailed measurement of stability and dose dependent behavior.
Dependence of N-N and Me-N centers formation on thetemperature and duration of annealing, measurement with optical methods
Nikel and cobalt have different solubilities in diamond andform different types of defects.
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
CDD Dependence on the Time and Dose, sample Desy7
CCD versus Dose
-10,00
0,00
10,00
20,00
30,00
40,00
50,00
0,00 0,30 0,60 0,90 1,20 1,50
Dose, Gy
CC
D,
mcm
Desy7
Strong polarisation effects can explain this behavior
CCD versus time
0,00
5,00
10,00
15,00
20,00
25,00
30,00
35,00
0:00 2:00 4:00 6:00
time
CC
D,
mcm
CDD Dependence on the Time and Dose, sample FAP7.3
CCD versus Dose
-10,00
0,00
10,00
20,00
30,00
40,00
0,00 0,10 0,20 0,30 0,40
Dose, Gy
CC
D,
mcm
Polarization effects are expressed even stronger
CCD versus time
0,00
5,00
10,00
15,00
20,00
25,00
30,00
35,00
0:00 2:00 4:00 6:00 8:00 10:00
time
CC
D,
mcm
DESY7 with Replaced MetallizationTi-Ag with proper annealing for titanium carbidization
CCD versus Voltage
0
10
20
30
40
50
60
70
0 60 120 180 240 300
U, V
CC
D, m
cm
Dose related behavior hadn’t changed,but the value of CCD before irradiation increased twofold(CCD = 32m with old metallization, CCD = 65m with new metallization).
CCD versus Dose
0
10
20
30
40
50
60
70
0 5 10 15 20 25 30
Dose, GyC
CD
, mcm
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)
Thickness 500mcm
MIP charge 30000e
Bias voltage 100V
Pad number 87
Sensor segment layout Sensor specifications
The sensor, output connectors and a power supply connector are mounted on a common PCB
AS01PDA ASIC meet the detector requirements
AS01PDA main parameters
Channelstructure
Preamplifier -Shaper -50 Ohm Driver
Shaper peaking time
90ns
Maximumdifferential gain
9mV/fC
ENC, e 1000+14.1e/pF
Shaper output +/-1.5V
Powerconsumption
18mW
Package SOP16
ENC vs Cd and Vcc
ENC = 14,123e/pF + 1000e
0
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
0 50 100 150 200 250 300
Cd, pF
EN
C,
e
5V
6V
7V
8V
9V
Trend line
AS01PDA block diagram
Positive output (Op)
Negativeoutput(On)
Preamplifier- Shaper- 50 Ohm Driver
1st 3rd
Gain control
Signal input(In)
Ct 0.2pF
Test input(In_t)
2nd
Reference preamplifier
P N
Reference level
AS01PDA on the small PCB and eight channels flat bar PCB
Main unit of the FEE prototype
One flat bar of theFEE prototype
The GaAs prototype electronics will consist of eleven PCB flat bars(87 channels)
FEE prototype measurement results Gain and waveform versus detector capacitancein response to 10fC input charge
Linearity measurements done by Krzysztof Oliwa and Wojciech Wierba
Linearity at different power supply voltages
The IC was earlier tested with Tomsk GaAs detectors (1cm x 1cm) andshown good results
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
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.