121460348
Irradiation tests of double-sided silicon strip detectors optimized for the ATLAS-inner-detector-region
Abstract Silicon detectors, which will be used as tracking detectors in LHC-experiments, face special requirements; one major challenge is the long term operation of the detectors in very intense radiation fields. This paper describes a design for double-sided strip detectors, which takes these requirements into account. Irradiation tests have been carried out using 24 GeV protons. The change of detector characteristics in particular guardring-behaviour, punchthrough biasing and interstrip isolation has been studied.
120803754
Study of a DEPJFET pixel matrix with continuous clear mechanism
Abstract A new kind of silicon pixel detector with integrated amplification has been built and tested. Each pixel consists of a p -channel JFET located on a fully depleted substrate. The pixel size can be customized by using a drift-chamber-like transport mechanism in each pixel. The homogeneity of the signal response of a small matrix was investigated with a laser diode. The measured rise time and gain of the device are analyzed with a simple small signal model.
111334701
A DEPFET pixel matrix system for the ILC vertex detector
Abstract The DEPFET detector offers radiation detection and amplification jointly by embedding a field effect transistor into fully depleted silicon. Due to the excellent noise performance ( ENC = 2.2 e - for single pixel at room temperature and 6 μ s shaping time) and the high spatial resolution of the device ( 4.3 μ m at 22 keV using 50 × 50 μ m 2 pixels), the DEPFET concept is attractive for X-ray astronomy, for biomedical application and for tracking in particle physics. For the vertex detector of a future TeV-scale linear collider, like the proposed ILC (International Linear Collider), a highly granulated pixel system operated row-wise with line rates of 20 MHz at a noise level below 100 e - is needed. Addressing these requirements, improved DEPFET sensors with 22 × 36 μ m 2 pixel size have been fabricated. A prototype system has been developed that uses dedicated chips for steering and readout of a 64 × 128 DEPFET pixel matrix. Due to the current based readout mode provided by the readout chip, a thousand times faster matrix operation than achieved so far is possible. The performance of the single components of the system will be summarized and first results obtained with the entire system will be presented.
73653251
Imaging performance of a DEPFET pixel Bioscope system in Tritium autoradiography
Abstract A Bioscope system based on a 64 × 64 -matrix of DEPFET pixels has been developed for real-time digital autoradiography in biomedical applications. It provides very good energy and spatial resolution at the same time. The DEPFET pixel cells consist of p -channel JFETs integrated into the high-ohmic n -silicon substrate. This leads to a very low noise performance at room temperature. Two dedicated ASIC chips have been developed for steering and readout of the pixel matrix. The measured system noise of ( 69 ± 4 ) e - at 35 ∘ C is mostly due to sensor leakage current and can be largely reduced by cooling or a faster readout. The spatial resolution is examined by measurements with a laser as well as with a dedicated test chart and is determined to be ( 6.7 ± 0.7 ) μ m for 6 keV-X-rays and 4.3 ± 0.8 μ m for 22 keV-X-rays. The measurements are compared to simulation results with different reconstruction algorithms. Due to the thin entrance window at the detector backside and the low noise performance, a detection of low-energy β -emitters such as 3H is possible. Measurements with 3H-labeled biological samples were taken. The ability of the DEPFET pixel Bioscope to separate different radiolabels in the same sample is demonstrated by a measurement with 3H and 14C.
13052670
Prospects of using silicon photomultipliers for the astroparticle physics experiments EUSO and MAGIC
We discuss the silicon photomultiplier as a novel photon detector for the Major Atmospheric Gamma Imaging Cerenkov Telescope and the Extreme Universe Space Observatory. For these astroparticle experiments we pursue two different developments of the SiPM. One development is pursued at MEPhI, where prototypes are available. In the course of this paper we will describe some characteristics of these devices. The second development, which is using the back illumination principle is at present in its design phase.
67778447
A fast readout using switched current techniques for a DEPFET-pixel vertex detector at TESLA
Abstract A fully depleted silicon detector with a first amplifying transistor integrated in every pixel (DEPFET) is a promising proposal for the pixel-based vertex detector at TESLA. The DEPFET offers good spatial resolution, an excellent signal-to-noise ratio and low power consumption in a row-wise operation mode. A readout concept for a DEPFET pixel array matching the requirements at TESLA is described. In order to meet the operation specifications at TESLA ( 50 MHz row rate), a readout architecture based on current mode techniques (Switched Current) is presented. It contains stand alone zero suppression offering a triggerless operation. The core of the readout chip, a fast operating current memory cell, is discussed in detail. The results of a first prototype chip, CURO I (CUrrent ReadOut), show that the requirements for TESLA are achievable.
43889438
Performance of fast high-resolution Muon drift tube chambers for LHC upgrades
Monitored drift tube chambers are used as precision tracking detectors in the muon spectrometer of the ATLAS experiment at the LHC at CERN. These chambers provide a spatial resolution of 35 mm and a tracking efficiency of close to 100 % up to background rates of 0.5 kHz/cm2, the former being limited at higher rates mainly due to space charge effects and the latter due to the maximum drift time of 700 ns. For LHC upgrades, a faster drift tube chamber has been developed, using drift tubes with a diameter of 15mm instead of 30 mm. The increased channel density and shorter drift time of about 200 ns raise the rate capability to about 10 kHz/cm2, while retaining the spatial resolution. A prototype chamber with trapezoidal shape consisting of 2×8 layers of 15mm diameter drift tubes with an active surface of 0.8 m2 has been constructed. This chamber has been tested at CERN with a 180 GeV muon beam (H8) and with cosmic ray muons at the Gamma Irradiation Facility (GIF) at high g radiation rates.
108271361
Concepts for the readout of time projection chambers
While the use of CCD’s for the readout of TPC’s offers a reliable and ever more of the digitization concept. The problem of precision of currently available FADC’s is discussed together with two proposals for a solution.
50340039
Observation of a Narrow Resonance at 10.02-GeV in e+ e- Annihilations
Abstract The ϒ′ state has been observed as a narrow resonance at M ( ϒ ′) = 10.02 ± 0.02 GeV in e + e − annihilations, using a NaI and lead-glass detector in the DORIS storage ring at DESY. The ratio Г ee Г had /Г tot of electronic, hadronic, and total widths has been measured to be 0.32 ± 0.13 keV. The parameters of the Г particle have also been determined to be/ M (Г)
92988840
Resolution and efficiency of the ATLAS muon drift-tube chambers at high background rates
Abstract The resolution and efficiency of a precision drift-tube chamber for the ATLAS muon spectrometer with final read-out electronics was tested at the Gamma Irradiation Facility at CERN in a 100 GeV muon beam at photon irradiation rates of up to 990 Hz / cm 2 , which corresponds to twice the highest background rate expected in ATLAS. A silicon strip detector telescope served as external reference in the beam. The pulse-height measurement of the read-out electronics was used to perform time-slewing corrections, which lead to an improvement of the average drift-tube resolution from 104 to 82 μ m without irradiation, and from 128 to 108 μ m at the maximum expected rate. The measured drift-tube efficiency agrees with the expectation from the dead time of the read-out electronics up to the maximum expected rate.
22887218
Construction of a high-resolution muon drift tube prototype chamber for LHC upgrades
The proposed upgrade of the Large Hadron Collider at CERN to luminosities above 1 × 1034 cm−2 s−1 necessitates the replacement of a large number of tracking chambers of the muon spectrometer of the ATLAS experiment to avoid deterioration of the muon identification and the momentum measurement at high background rates. Based on the standard ATLAS Monitored Drift Tube chambers (2 × 3 or 4 tube layers, drift tube diameter 30 mm), a new design with 15 mm diameter tubes and matching services has been developed, offering an increased rate capability and better pattern recognition and redundancy due to the higher cell density. A full-sized prototype chamber consisting of 1152 tubes arranged in 2 × 8 tube layers and covering an area of 1 m2 has been built to validate the assembly procedures and to test its performance.