120 likes | 227 Views
Current Status of Diamond Sensors R&D in Minsk Group. Presented by Igor Emeliantchik. FCAL Collaboration Meeting @ Institute of Nuclear Physics PAN February 12-13, 2006, Krakow, Poland. Diamond activities at NC PHEP, Minsk – two directions:
E N D
Current Status of Diamond Sensors R&Din Minsk Group Presented by Igor Emeliantchik FCAL Collaboration Meeting@ Institute of Nuclear Physics PAN February 12-13, 2006, Krakow, Poland
Diamond activities at NC PHEP, Minsk – two directions: • 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 • diamondof Minsk production
Spectrometric Setupfor 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 = Gb(hb,xped,ped) + Gs(hs,xs,s) xped 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/R2 . DRDiamond= 0.832DRSi(for 1 cm2 CVD diamond detector with thickness 300m) 37MBq 90Sr 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 Doses Larger Doses
FAP1.1 CCD versus Voltage at Different Pumping States 250Gy 15Gy 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 mm3 Charge Collection Distance achieved so far: 40m
Properties of the Best Sample CCD: 40m Coating: Ti - Ag
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 K2NO3 • 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 40m is developed