FCAL R&D in Minsk Group: Sensors and Electronics FCAL Collaboration 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 90 Sr Paraffin collimator 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 Averaged amplitude of response to the whole  -spectrum of 90 Sr was measured with digital oscilloscope at each dose point. Detector behavior seems to demonstrate classical pumping effect, 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 dose measured in standard way 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 the temperature and duration of annealing, measurement with optical methods Nikel and cobalt have different solubilities in diamond and form different types of defects.

Freiburg CVD Diamonds Measurement of Charge Collection Distance Desy7, before irradiationDesy7, 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 Strong polarisation effects can explain this behavior

CDD Dependence on the Time and Dose, sample FAP7.3 Polarization effects are expressed even stronger

DESY7 with Replaced Metallization Ti-Ag with proper annealing for titanium carbidization Dose related behavior hadn’t changed, but the value of CCD before irradiation increased twofold (CCD = 32  m with old metallization, CCD = 65  m with new metallization).

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) Thickness500mcm MIP charge30000e Bias voltage100V Pad number87 Sensor segment layoutSensor 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 Channel structure Preamplifier - Shaper - 50 Ohm Driver Shaper peaking time 90ns Maximum differential gain 9mV/fC ENC, e e/pF Shaper output+/-1.5V Power consumption 18mW PackageSOP16

AS01PDA block diagram

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)

FEE prototype measurement results Gain and waveform versus detector capacitance in 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) and shown 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.