Current Status of Diamond Sensors R&D in Minsk Group FCAL Collaboration Institute of Nuclear Physics PAN February 12-13, 2006, Krakow, Poland Presented by Igor Emeliantchik

Diamond activities at NC PHEP, Minsk – two directions: 1.Development of the spectrometric setup for measurement of the main parameters of quality of diamond detectors and investigation of Freiburg diamonds with its help 2. Development of detector on the base of monocrystalline diamond of Minsk production

Spectrometric Setup for Charge Collection Distance Measurement NIM + CAMAC LeCroy 2249W ADC “Tetrode” preamp Paraffin collimator absorbs scattered  -particles with minimal bremsstrahlung thus improving trigger efficiency

FAP1.1 MIP Spectrum and Fitting Procedure Background Spectrum MIP Spectrum Fitting: f = G b (h b,x ped,  ped ) + G s (h s,x s,  s ) x ped and  ped are fixed Electronics noise is much larger than energy deposition fluctuations, so no Landau distrubution is taken into consideration

FAP1.1 CCD versus Voltage The diamond is “pumped” with 15 Gy

Dose Estimation D = p0 + p1/R 2. DR Diamond = 0.832DR Si (for 1 cm2 CVD diamond detector with thickness 300  m) 37MBq 90 Sr source, lying on the top of the diamond (the distance is about 1mm) The Dose Rate: 170 Gy/h

FAP1.1 CCD versus Dose Small DosesLarger Doses

FAP1.1 CCD versus Voltage at Different Pumping States 15Gy 250Gy 0Gy 30 minutes of UV irradiation reliably resets the diamond from “pumped” state to “initial” one

Minsk Monocrystalline Diamond Detectors High Pressure High Temperature Technology Typical Dimensions: 3  3  0.5 mm 3 Charge Collection Distance achieved so far: 40  m

Properties of the Best Sample Coating: Ti - Ag CCD:  40  m

Some Details on the Technology Annealing at high pressure and high temperuture for passivation of nitrogen impurities is currently tested with some promising results. (nitrogen atoms are being moved from replacing position in the lattice to aggregated state) Polishing of the diamond surface before metallization helps to minimize polarization effects. Surface etching in melted K 2 NO 3 Thermo-mechanical polishing – dissolving of defective surface layer in melted metal with its consequent removing

Conclusions Spectrometric setup for CCD measurement is completed and tested with FAP1.1 diamond detector FAP1.1 diamond demostrates classic “pumping” effect and rather stable behavior after accumulation of initial “pumping” dose Monocrystalline detector based on the diamond of Minsk production with CCD of  40  m is developed