W. Rowe

Temperature effects on radiation damage to silicon detectors

Abstract Motivated by the large particle fluences anticipated for the SSC and LHC, we are performing a systematic study of radiation damage to silicon microstrip detectors. Here we report radiation effects on detectors cooled to 0°C (the proposed operating point for a large SSC silicon tracker) including leakage currents and change in depletion voltage. We also present results on the annealing behavior of the radiation damage. Finally, we report results of charge collection measurements of the damaged detectors made with an 241 Am α source.

A fast shaping low power amplifier-comparator integrated circuit for silicon strip detectors

We have designed and tested a 64 channel amplifier-comparator integrated circuit on the Maxim SHPi bipolar process. The low power design, 840 /spl mu/W/channel, is intended for use as a frontend with high clock rate silicon strip detector systems. Peaking time at the comparator input is 20 ns, for good double pulse resolution, and noise is near optimum for the technology used. We have used the chip successfully in a proton beam test at KEK in Japan with a 40 MHz data clock. >

Development of radiation-hard materials for microstrip detectors

We present the search for new detector materials, which would replace silicon as the bulk material in strip detectors for application in high radiation fields. The investigation focuses on SiC, a material with higher bandgap and thus less degradation after irradiation when compared with silicon. Both static properties like the capacitance and leakage currents and dynamic measurements of the charge collection with low-noise amplifiers are presented.

Evaluation of p-stop structures in the n-side of n-on-n silicon strip detectors

A large area (63.6 mm/spl times/64 mm) n-on-n silicon strip detector was fabricated, implementing various p-stop structures in the n-side. The detectors were characterized in laboratory and in beam tests. The inter-strip capacitance showed features in which the individual p-stop structure had the longest tail toward saturation. The beam tests showed other p-stop structures collected more charge in the mid-strip region than the individual p-stop structure. In addition, there was a source which lost or spread charge and induced noise where the over-depletion was insufficient.

Signal-to-noise in silicon microstrip detectors with binary readout

We report the results of a beam test at KEK using double-sided AC-coupled silicon microstrip detectors with binary readout, i.e., a readout where the signals are discriminated in the front-end electronics and only the hit location as kept. For strip pitch between 50/spl mu/ and 200/spl mu/, we determine the efficiency and the noise background as function of threshold setting. This allows us to reconstruct the Landau pulse height spectrum and determine the signal/noise ratio. In addition, the threshold/noise ratio necessary for operation with low occupancy is determined. >

The Mark III spectrometer

Abstract This paper describes the design, construction and performance of the Mark III, a new general purpose large solid angle spectrometer at SPEAR, the SLAC 2–8 GeV e+e− storage ring. The detector has been designed for the study of exclusive final states in e+e− annihilation, which requires large solid angle coverage combined with charged particle momentum resolution, particle identification, and photon detection efficiency at low energies.

Noise measurements on radiation-hardened CMOS transistors

The authors present a measurement of the spectral noise density of radiation-hardened CMOS transistors. The motivation of this work is the design of a low-power, low-noise frontend with fast shaping for a silicon microstrip tracking detector for the SSC (Superconducting Super Collider). NMOS and PMOS transistors with widths varying from 75 mu m to 1332 mu m and lengths of 1.2, 2.2 and 3.2 mu m produced by UTMC (United Technology Microelectronics Center) were subjected to total /sup 60/Co doses of up to 5 Mrad. Radiation effects on the transconductance and on both the white and the frequency-dependent noise are described.<<ETX>>

The silicon tracker of the beam test engineering model of the GLAST large-area telescope

The silicon tracker for the engineering model of the GLAST Large Area Telescope(LAT) has at least two unique features: it employs self triggering readout electronics, dissipating less than 200 mu-W per channel and to date represents the largest surface of silicon microstrip detectors assembled in a tracker (2.7 m{sup 2}). It demonstrates the feasibility of employing this technology for satellite based experiments, in which low power consumption, large effective areas and high reliability are required. This note describes the construction of this silicon tracker, which was installed in a beam test of positrons, hadrons and tagged photons at SLAC in December of 1999 and January of 2000.

Measurement of dose rate dependence of radiation induced damage to the current gain in bipolar transistors

We report the study of radiation induced change in the current gain of bipolar transistors for three different gamma dose rates. The dose rates differed by a factor of 60 with the lowest close to that anticipated for the LHC, and the highest at a rate we have been routinely using for radiation damage tests. The maximum dose attained was 200 kRad, which is high enough to compare with other measurements. The importance of annealing to high dose rate data is demonstrated.

Beam tests of a double-sided silicon strip detector with fast binary readout electronics before and after proton-irradiation

Abstract A double-sided silicon strip detector with a radiation-tolerant design was fabricated and characterized in a sequence of beam tests at KEK using 4 GeV/ c pions. The detectors were combined with newly designed, fast, lower power, bipolar amplifier-shaper-discriminator chips and CMOS digital pipeline chips to record hit-no hit signals in the strips. Efficiencies, noise occupancies, and spatial resolutions were measured before and after the proton irradiation at an equivalent fluence of 1 × 10 14 p/cm 2 , depending on angle of track incidence and strip-pitches. The median pulse height distribution, derived from the threshold scans of the efficiency, allowed to extract the response of the detector. A 1 T magnetic field enabled us to determine the Hall mobilities of electrons and holes.