T. Dubbs

Design and performance of the ABCD chip for the binary readout of silicon strip detectors in the ATLAS semiconductor tracker

The ABCD design is a single chip implementation of the binary readout architecture for silicon strip detectors in the ATLAS semiconductor tracker. The prototype chip has been manufactured successfully in the DMILL process. In the paper we present the design of the chip and the measurement results. The basic analogue performance of the ABCD design has been evaluated using a prototype SCT module equipped with the ABCD chips. The digital performance has been evaluated using a general purpose IC tester. The measurements confirmed that all blocks of the ABCD design are fully functional and the chips meet all basic requirements of the SCT. Wafer screening has been performed using a customised wafer tester.

Observation of beta and X rays with 3-D-architecture silicon microstrip sensors

The first silicon radiation sensors based on the three-dimensional (3-D) architecture have been successfully fabricated. X-ray spectra from iron-55 and americium-241 have been recorded by reading out a 3-D architecture detector via wire bonds to a low-noise, charge-sensitive preamplifier. Using a beta source, coincidences between a 3-D sensor and a plastic scintillator were observed. This is the first observation of ionizing radiation using a silicon sensor based on the 3-D architecture. Details of the apparatus and measurements are described.

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.

Efficiency and noise measurements of non-uniformly irradiated double-sided silicon strip detectors

Abstract We have investigated the efficiency and the noise occupancy of double-sided silicon strip detectors, which were subjected to non-uniform proton irradiation of fluences up to a maximum of equivalent 5 × 10 13 protons/cm 2 . The depletion voltages, varying over time due to controlled annealing, were close to zero on one end of the 6 cm strips and 190 V at the high radiation end. We determined the efficiency and noise occupancy on both n-side and p-side in a 106 Ru telescope, using a binary read-out system with 22 ns shaping time. The n-side exhibits superior performance after type inversion.

Progress in development of the readout chip for the ATLAS semiconductor tracker

The development of the ABCD chip for the binary readout of silicon strip detectors in the ATLAS Semiconductor Tracker has entered a pre-production prototyping phase. Following evaluation of the ABCD2T prototype chip, necessary correction in the design have been implemented and the ABCD3T version has been manufactured in the DMILL process. Design issues addressed in the ABCD3T chip and performance of this pre-production prototype are discussed.

Voltages on silicon microstrip detectors in high radiation fields

The voltage between the AC-coupled readout strips and the silicon strip implants on a silicon microstrip detector in a high radiation field was investigated. The ionizing radiation was supplied by infrared lasers of varying intensity, creating ionization patterns that mimic those created by a flux of minimum ionizing particles. At high laser intensities, a complete breakdown of the operational electric field within the detector was achieved and studied as a function of laser intensity and connected circuit components. It was discovered that for a single-sided silicon microstrip detector, with n-type bulk, n-type silicon implant strips, and a p-type backplane, the voltage difference between the readout strips and the silicon implants could be minimized by using a large resistor between the backplane and the bias supply, and a small capacitor between the backplane and ground.

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. >

A comparison of the performance of irradiated p-in-n and n-in-n silicon microstrip detectors read out with fast binary electronics

Abstract Both n-strip on n-bulk and p-strip on n-bulk silicon microstrip detectors have been irradiated at the CERN PS to a fluence of 3×10 14 p cm −2 and their post-irradiation performance compared using fast binary readout electronics. Results are presented for test beam measurements of the efficiency and resolution as a function of bias voltage made at the CERN SPS, and for noise measurements giving detector strip quality. The detectors come from four different manufacturers and were made as prototypes for the SemiConductor Tracker of the ATLAS experiment at the CERN LHC.

Characterization of an irradiated double-sided silicon strip detector with fast binary readout electronics in a pion beam

We report on the characterization of an AC-coupled, double-sided silicon strip detector, with fast binary readout electronics, in a pion beam before and after proton irradiation. The proton irradiation was non-uniform and to increase the damage the detector was heated to accelerate the anti-annealing. The effective radiation level was about 1/spl times/10/sup 14/ p/cm/sup 2/. Both the bias voltage of the detector and the threshold of the discriminator of the binary readout electronics were varied, and the efficiencies were determined. The irradiated detector clearly shows the effect of bulk inversion. The binary system proved to be efficient well below the full depletion voltage on the p-n junction side. Due to the highly non-uniform irradiation, the depletion voltage changes from close to zero to about 120 V along a single strip, but the detector appears to work without any noticeable failures.