Roland Horisberger

Mythen detector system

Time-resolved experiments in powder diffraction are limited by the long time required to record spectra with current detectors. A major improvement can be made by using a massively parallel X-ray detection system together with a fast read out. The Mythen detector (Microstrip system for time-resolved experiments) has been built for the Powder Diffraction Station of the Material Science beamline at the Swiss Light Source to meet these requirements. The specifically developed read out chip (Mythen chip), the detector system and first measurements are shown.

The H1 silicon vertex detector

Abstract The design, construction and performance of the H1 silicon vertex detector is described. It consists of two cylindrical layers of double-sided, double-metal silicon sensors read out by a custom designed analog pipeline chip. The analog signals are transmitted by optical fibres to a custom-designed ADC board and are reduced on PowerPC processors. Details of the design and construction are given and performance figures from the first data-taking periods are presented.

PILATUS: a two-dimensional X-ray detector for macromolecular crystallography

A large quantum-limited area X-ray detector for protein crystallography is under development at the Swiss Light Source. The final detector will be 2k � 2k pixels covering 40 � 40 cm 2 : A three-module prototype with 1120 � 157 pixels covering an active area of 24:3 � 3: 4c m 2 has been tested. X-rays above 6 keV with peak count rates exceeding 5 � 10 5 X-ray/pixel/s could be detected in single photon counting mode. Statistics of module production and results of threshold trimming are presented. To demonstrate the potential of this new detector, protein crystal data were collected at beamline 6S of the SLS. r 2002 Elsevier Science B.V. All rights reserved. PACS: 87.64.Bx

A novel readout chip for silicon strip detectors with analog pipeline and digitally controlled analog signal processing

Abstract A readout chip for silicon strip detectors with analog event pipeline has been fabricated (SACMOS 2 μm technology) and tested. The chip has been designed to operate at the HERA ep collider at a bunch crossing rate of 10.4 MHz. Each channel has a layout width of 44 μm and consists of a fast, low noise, low power preamplifier followed by a switched capacitor analog event pipeline. The preamplifier consists of a single CMOS push-pull gain cell and offers minimal power consumption. A novel feature of our chip is a self-reading architecture that allows the preamplifier to re-read its own pipeline buffers and thus permits a extensive parallel analog signal processing that is digitally controlled. The results from radiation damage tests with 60 Co are given for doses up to 240 krad.

Design and performance of the silicon sensors for the CMS barrel pixel detector

The CMS experiment at the LHC includes a hybrid silicon pixel detector for the reconstruction of charged tracks and of the interaction vertices. The barrel region consists of n-in-n sensors with 100X150 um^2 cell size processed on diffusion oxygenated float zone silicon. A biasing grid is implemented and pixel isolation is achieved with the moderated p-spray technique. An extensive test program was carried out on the H2 beam line of the CERN SPS. In this paper we describe the sensor layout, the beam test setup and the results obtained with both irradiated and non-irradiated prototype devices. Measurements of charge collection, hit detection efficiency, Lorentz angle and spatial resolution are presented.

A pixel detector for the protein crystallography beamline at the SLS

At the Paul Scherrer Institute a new synchrotron light source is currently under construction, the Swiss Light Source (SLS), which will be operational in summer 2001. Among the first beamlines is a high brightness, micro-focusing protein crystallography beamline. It will be equipped with a pixel detector, which has several features of interest for the next generation of protein crystallography detectors. The point spread function and the effect of charge sharing was measured with a prototype detector in a test experiment at the European Synchrotron Radiation Facility in Grenoble. The concepts of the SLS pixel detector is presented as well as test results from radiation hard prototype chips.

Silicon sensors development for the CMS pixel system

The CMS experiment will operate at the Large Hadron Collider (LHC). A hybrid pixel detector located close to the interaction region of the colliding beams will provide high resolution tracking and vertex identification which will be crucial for b quark identification. Because of the radiation environment of the LHC, the performance of the sensors must be carefully evaluated up to a fluence of 6 � 10 14 neq cm � 2 . We expect that the sensors will be operated partially depleted during their operation at the LHC and we have implemented an n + on n sensor design. We have irradiated prototype sensors to a dose of 1 � 10 15 neq cm � 2 . We present the results of our testing before and after irradiation.

Continuous sample rotation data collection for protein crystallography with the PILATUS detector

The PILATUS detector (pixel apparatus for the SLS) is a large all silicon quantum-limited area X-ray detector for protein crystallography. A three-module array with 1120 � 157 pixels covering an active area of 24.3 � 3.6 cm 2 is in operation. Its main features are an excellent point-spread function, a very high dynamic range and a readout time of o7 ms. X-rays with energy above 6 keV can be detected in single photon counting mode. To demonstrate the potential of the detector, fine f-sliced protein crystal data were collected in continuous sample rotation mode at beamline X06SA of the SLS. r 2003 Elsevier B.V. All rights reserved.

Sensor development for the CMS pixel detector

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THE BIPOLAR SILICON MICROSTRIP DETECTOR: A PROPOSAL FOR A NOVEL PRECISION TRACKING DEVICE

It is proposed to combine the technology of fully depleted silicon microstrip detectors fabricated on n doped high resistivity silicon with the concept of the bipolar transistor. This is done by adding a n++ doped region inside the normal p+ implanted region of the reverse biased p+ n diode. Teh resulting structure has amplifying properties and is referred to as bipolar pixel transistor. The simplest readout scheme of a bipolar pixel array by an aluminium strip bus leads to the bipolar microstrip detector. The bipolar pixel structure is expected to give a better signal-to-noise performance for the detection of minimum ionizing charged particle tracks than the normal silicon diode strip detector and therefore should allow in future the fabrication of thinner silicon detectors for precision tracking.