T. Fiutowski

Forward instrumentation for ILC detectors

Two special calorimeters are foreseen for the instrumentation of the very forward region of the ILC detector, a luminometer designed to measure the rate of low angle Bhabha scattering events with a precision better than 10?3 and a low polar angle calorimeter, adjacent to the beam-pipe. The latter will be hit by a large amount of beamstrahlung remnants. The amount and shape of these depositions will allow a fast luminosity estimate and the determination of beam parameters. The sensors of this calorimeter must be radiation hard. Both devices will improve the hermeticity of the detector in the search for new particles. Finely segmented and very compact calorimeters will match the requirements. Due to the high occupancy fast front-end electronics is needed. The design of the calorimeters developed and optimised with Monte Carlo simulations is presented. Sensors and readout electronics ASICs have been designed and prototypes are available. Results on the performance of these major components are summarised.

X-ray fluorescence imaging system for fast mapping of pigment distributions in cultural heritage paintings

Conventional X-ray fluorescence imaging technique uses a focused X-ray beam to scan through the sample and an X-ray detector with high energy resolution but no spatial resolution. The spatial resolution of the image is then determined by the size of the exciting beam, which can be obtained either from a synchrotron source or from an X-ray tube with a micro-capillary lens. Such a technique based on a pixel-by-pixel measurement is very slow and not suitable for imaging large area samples. The goal of this work is to develop a system capable of simultaneous imaging of large area samples by using a wide field uniform excitation X-ray beam and a position sensitive and energy dispersive detector. The development is driven by possible application of such a system to imaging of distributions of hidden pigments containing specific elements in cultural heritage paintings, which is of great interest for the cultural heritage research. The fluorescence radiation from the area of 10 × 10 cm2 is projected through a pinhole camera on the Gas Electron Multiplier detector of the same area. The detector is equipped with two sets of orthogonal readout strips. The strips are read out by the GEMROC Application Specific Integrated Circuits (ASIC)s, which deliver time and amplitude information for each hit. This ASIC architecture combined with a Field Programmable Gate Array (FPGA) based readout system allows us to reconstruct the position and the total energy of each detected photon for high count rates up to 5 × 106 cps. Energy resolution better than 20% FWHM for the 5.9 keV line and spatial resolution of 1 mm FWHM have been achieved for the prototype system. Although the energy resolution of the Gas Electron Multiplier (GEM) detector is, by principle, not competitive with that of specialised high energy resolution semiconductor detectors, it is sufficient for a number of applications. Compared to conventional micro-XRF techniques the developed system allows shortening of the measurement time by 2-3 orders of magnitude.

Design for good matching in multichannel low-noise amplifier for recording neuronal signals in modern neuroscience experiments

Abstract The paper reports on the design of a prototype 16-channel ASIC for readout of signals from live neuronal systems. Single channel comprises a low-noise amplifier and a low-frequency pass-band filter. The amplifier design optimised with respect to noise and power consumption is discussed. The design of a continuous-time high-pass filter with lower cut-off frequency as low as 20 Hz, which is suitable for realisation in a CMOS process, is presented. Special attention is paid to uniformity of analogue parameters in the multichannel IC. Channel matching is evaluated by Monte Carlo simulation. The design has been fabricated in a 0.7 μm CMOS process and measurements of basic parameters and characteristics have been performed for the prototypes. Good agreement between the simulation and measurements has been achieved for single channel parameters as well as for channel matching. The obtained results on channel matching are discussed with respect to design reliability and production yield.

A general purpose multichannel readout system for radiation detectors

The design and performance of a multichannel readout system for radiation detectors are presented. The developed 32-channel prototype system comprises fast, low-noise, front-end followed by a 10-bit multichannel digitizer and on-board FPGA data concentrator, processing the stream of digitized data with up to 6.4 Gbps rate. The operation of the whole system is managed by a microcontroller. The system can work in self-triggering mode or can be triggered externally. The implemented trigger mechanism allows for elaborate event filtering and selection of data to be transmitted to the host through the USB interface. A wide spectrum of measurements showing and quantifying the key system parameters like data transmission rate and event rate, noise, and gain are presented to prove the correct system performance. To increase the power efficiency in experiments with a non-continuous beam structure, a power pulsing mechanism is implemented and verified experimentally.

Diagnostic sensitivity of SPECT myocardial perfusion imaging using a pumping cardiac phantom with inserted variable defects

BackgroundThe diagnostic sensitivity of various SPECT MPI procedures was assessed using a pumping cardiac phantom with variable defects inserted in the myocardial wall of the left ventricle.Methods and ResultsA diagnostic evaluation of 142 myocardial defects was performed. A diagnosis blinded to prior-known conditions was compared to the known defects severity (transmural, subendocardial) and defects position within the myocardial wall of the left ventricle (apical, anterior, inferior) for three body types (average male, large male, large female). Non-attenuation corrected, attenuation corrected and gated SPECT MPI were performed. The diagnostic sensitivity was improved when applying attenuation correction or gating techniques to identify subendocardial defects in the inferior, anterior and apical segments of the myocardial wall of the left ventricle for all three body types. Transmural defects could be identified without any attenuation correction or gating.ConclusionsThe diagnostic sensitivity was improved when applying AC or GSPECT techniques.

Design and performance of the GEMROC ASIC for 2-D readout of gas electron multiplier detectors

In this paper we report on the development of an Application Specific Integrated Circuit (ASIC) being a key component for two-dimensional readout of Gas Electron Multiplier (GEM) detectors in the Proton Range Radiography (PRR) system.

A power scalable 10-bit pipeline ADC for Luminosity Detector at ILC

The design and measurement results of a power scalable 10-bit pipeline ADC developed for the luminosity detector at the future International Linear Collider (ILC) are discussed. The prototype is designed and fabricated in 0.35 ?m CMOS technology. A wide spectrum of measurements of static (INL 58 dB, SINAD ~ 58 dB) parameters are performed to understand and quantify the circuit performance. The ADC works for sampling rates from 1 kS/s to 25 MS/s covering more than four orders of magnitude. In most of the range power consumption scales linearly with sampling rate with a factor of 0.85 mW/MS/s. With ILC beam structure and sampling rate of about 3.5 MS/s, using the implemented in ASIC power switching off feature, an average power consumption of about 15 ?W per channel may be obtained. The ADC layout is drawn with a constant pitch of 300 ?m to facilitate a multichannel implementation.

A compact system for two-dimensional readout of Gas Electron Multiplier detectors

There is a growing interest in the use of Gas Electron Multiplier (GEM) and other micro-pattern gas detectors (MPGD) for two-dimensional (2-D) position sensitive measurements of photons or charged particles. A Gas Electron Multiplier Readout Chip (GEMROC) is an Application Specific Integrated Circuit (ASIC) dedicated for 2-D strip readout of GEM detectors. The ASICs deliver the amplitudes and time coordinates of the signals recorded on two sets of orthogonal strips. Timing information is used for finding coincidences of signals on two spatial coordinates while amplitude information is used to find the center of gravity for the cluster of signals belonging to the same detection event. In this paper we present a Field Programmable Gate Array (FPGA) based compact readout system dedicated for these ASICs. The readout system consists of two synchronized FPGA-ADC boards connected to four front-end boards, each one equipped with two GEMROCs. Both FPGAs are connected to a DAQ PC using separate Gigabit Ethernet links. The DAQ PC is equipped with a dedicated C++ based software, which is responsible for configuration of the FPGAs and ASICs settings, storing all the incoming data as well as for on-line/off-line data processing and visualization. The performance of the system is illustrated by test bench measurements.

A 10-Bit Multichannel Digitizer ASIC for Detectors in Particle Physics Experiments

The design and measurement results of a multi-channel power scalable 10-bit digitizer ASIC developed for the luminosity detector at the future linear colliders (ILC/CLIC) are discussed. The 8 channel prototype with different modes of output data serialization was designed and fabricated in a 0.35 μm CMOS technology. The ASIC works for sampling rates from about 10 kS/s to 25 MS/s (50 MS/s in single channel mode) allowing linear scaling of ADCs and serializer power consumption (0.8 mW/MS/s ADC core, 1.2 mW/MS/s total per channel). A wide spectrum of static and dynamic measurements confirm very good ADC resolution (ENOB = 9.7 bits), excellent channel uniformity and negligible crosstalk. To profit from non-continuous detector operation in linear collider experiments and to save power consumption, fast periodic power pulsing is implemented.

MSGCROC - an ASIC for high count rate readout of position sensitive Microstrip Gas Chambers for thermal neutrons

In this paper we report on the development of an ASIC for readout of position sensitive neutron detectors based on low-pressure Micro-Strip Gas Chambers with solid composite 157Gd/CsI converter. Global counting rates of 108 cps for a detector area of 25×25 cm2 covered with 400×400 strips requiring 2 ns time resolution for coincidences of signals from X- and Y-strips set very demanding requirements for the ASIC performance.