Hera-B Detectors With P-Spray Isolation On The N-Side; Unirradiated Results

P-spray isolation of double-sided detectors is investigated by computer simulations and measurements on full-size detector prototypes. Simulations showed that boron p-spray implant doses 4.10(12), 6.10(12), and 8.10(12) cm(-2) and implant energy 60 keV would yield breakdown voltages above 200V for unirradiated detectors with oxide charge 2.10(11) cm(-2). The simulations showed that the breakdown voltage decreases with increasing p-spray dose. According to the computer simulations, the detectors should perform equally well after irradiation giving an oxide charge of 1.10(12)cm(-2). HERA-B strip detectors with p-spray isolation were manufactured, using the three simulated doses. The average breakdown voltages and standard deviations were 167 +/- 31 V for the 4.10(12) cm(-2) dose, 151 +/- 16 V for the 6.10(12) cm(-2) dose, and 127 +/- 13 V for the 8.10(12) cm(-2) dose. The measured decrease in breakdown voltage is in good agreement with the computer simulations.