M. Ionica

An innovative detection module concept for PET

The design of a Positron Emission Tomography detection module capable of working inside a Magnetic Resonant Imaging system is the main objective of the 4D-MPET project. Combining the two imaging technologies offers better soft tissue contrast and lower radiation doses by providing both functional and morphological information at the same time. The proposed detector will feature a three-dimensional architecture based on two tiles of Silicon Photomultipliers coupled to a single LYSO scintillator on both its faces. Silicon Photomultipliers are magnetic-field compatible photo-detectors with a very small size enabling novel detector geometries that allow the measurement of the Depth of Interaction as well as a high detector packing fraction to maximize system sensitivity. Furthermore they can be fabricated using standard silicon technology, have a large gain in the order of 106 and are very fast thus allowing evaluating the Time of Flight. Among the other features of the proposed detection system, the architecture of the innovative readout electronics will be also described which plays a relevant role for the achievement of the desired performance and is based on custom integrated circuits. Simulation results of the whole system show good performance in terms of time and spatial resolution: a timestamp of 100 ps is the ultimate performance achievable with the use of a double threshold technique along with fast electronics. Time over threshold is exploited to provide the energy information with a bin size of 400 ps. Moreover, a z resolution of 1.4 mm Full Width at Half Maximum can be achieved. The proposed detector can also be exploited in other tracking applications, such as High Energy Physics and Astrophysics.

Apparatus to study crystal channeling and volume reflection phenomena at the SPS H8 beamline

A high performance apparatus has been designed and built by the H8-RD22 collaboration for the study of channeling and volume reflection phenomena in the interaction of 400 GeV/c protons with bent silicon crystals, during the 2006 data taking in the external beamline H8 of the CERN SPS. High-quality silicon short crystals were bent by either anticlastic or quasimosaic effects. Alignment with the highly parallel (8 murad divergence) proton beam was guaranteed through a submicroradian goniometric system equipped with both rotational and translational stages. Particle tracking was possible by a series of silicon microstrip detectors with high-resolution and a parallel plate gas chamber, triggered by various scintillating detectors located along the beamline. Experimental observation of volume reflection with 400 GeV/c protons proved true with a deflection angle of (10.4+/-0.5) murad with respect to the unperturbed beam, with a silicon crystal whose (111) planes were parallel to the beam.

Measurements for the SiliPET project: A small animal PET scanner based on stacks of silicon detectors

In this paper we propose a new scanner for small-animal positron emission tomography (PET) based on stacks of double sided silicon detectors. Each stack is composed of 40 planar detectors with dimension 60 × 60 × 1 mm3 and 128 orthogonal strips on both sides to read the two coordinates of interaction, the third being the detector number in the stack. Multiple interactions in a stack are discarded by an exclusive OR applied between each plane detector of a stack. In this way we achieve a precise determination of the interaction point of the two 511 keV photons. The reduced dimensions of the scanner also improve the solid angle coverage resulting in a high sensitivity. Preliminary results were obtained with MEGA prototype tracker (11 double sided Si detector layers, each with a thickness of 0.5 mm and a strip pitch of 470 μm), divided into two stacks 2 cm apart made of respectively 5 and 6 prototype layers, placing a small spherical 22Na source in different positions. We report on the results, spatial resolution, imaging, spectral and timing performances obtained with double sided silicon detectors, manufactured by ITC-FBK, having an active area of 3 × 3 cm2 and a strip pitch of 500 μm. Two different strip widths of 300 μm and 200 μm, and two thicknesses of 1 mm and 1.5 mm, equipped with 64 orthogonal p and n strips on opposite sides were read out with the VATAGP2.5 ASIC, a 128-channel “general purpose” charge sensitive amplifier.

Experimental measurements for the SiliPET project: A small animal PET scanner based on stacks of silicon detectors

We have proposed a new scanner for small-animal positron emission tomography (PET) based on stacks of double sided silicon detectors. Each stack is composed of 40 planar detectors with dimension 60 times 60 times 1 mm3 and 128 orthogonal strips on both sides to read the two coordinates of interaction, the third being the detector number in the stack. Multiple interactions in a stack may be discarded. In this way we achieve a precise determination of the interaction point of the two 511 keV photons. The reduced dimensions of the scanner also improve the solid angle coverage resulting in a high sensitivity. Preliminary results were obtained with MEGA prototype tracker. In this work we present the results obtained with double sided silicon detectors, manufactured by ITC-Fondazione Bruno Kessler (Trento- Italy), having an active area of 3 times 3 cm2, a strip pitch of 500 mum, strip width of 300 mum and thickness of 1 mm, equipped with 64 orthogonal p and n strips on opposite sides. We are using two different kinds of analog front end electronic chains: a single channel prototype of an ASIC circuit designed by Politecnico di Milano for fast timing measurements and VATAGP2.5 ASIC by IDEAS to evaluate the spatial resolution.In this paper we propose a new scanner for small-animal positron emission tomography (PET) based on stacks of double sided silicon detectors. Each stack is composed of 40 planar detectors with dimension 60 × 60 × 1 mm3 and 128 orthogonal strips on both sides to read the two coordinates of interaction, the third being the detector number in the stack. Multiple interactions in a stack are discarded. In this way we achieve a precise determination of the interaction point of the two 511 keV photons. The reduced dimensions of the scanner also improve the solid angle coverage resulting in a high sensitivity. Preliminary results were obtained with MEGA prototype tracker (11 double sided Si detector layers, each with a thickness of 0.5 mm and a strip pitch of 470 microns), divided into two stacks 2 cm apart made of respectively 5 and 6 prototype layers, placing a small spherical 22Na source in different positions. We report on the results, spatial resolution, spectral and timing performances obtained with double sided silicon detectors, manufactured by ITC-FBK, having an active area of 3 x 3 cm2 and a strip pitch of 500 mm. Two different strip widths of 300 μm and 200 μm, and two thicknesses of 1 mm and 1.5 mm, equipped with 64 orthogonal p and n strips on opposite sides were read out with the VATAGP2.5 ASIC, a 128-channel “general purpose” charge sensitive amplifier. Each channel is composed of a low-noise/ low-power preamplifier, a shaper (peaking time of 3.1 μs) with sample/hold, multiplexed analogue readout and a fast shaper (peaking time of 1.1 μs) that gives a trigger signal.

A pulsed nanosecond IR laser diode system to automatically test the Single Event Effects in the laboratory

A pulsed nanosecond IR laser diode system to automatically test the Single Event Effects in laboratory is described. The results of Single Event Latchup (SEL) test on two VLSI chips (VA HDR64, 0.8 and 1:2 mm technology) are discussed and compared to those obtained with high-energy heavy ions at GSI (Darmstadt). r 2002 Elsevier Science B.V. All rights reserved.

INFN Camera demonstrator for the Cherenkov Telescope Array

The Cherenkov Telescope Array is a world-wide project for a new generation of ground-based Cherenkov telescopes of the Imaging class with the aim of exploring the highest energy region of the electromagnetic spectrum. With two planned arrays, one for each hemisphere, it will guarantee a good sky coverage in the energy range from a few tens of GeV to hundreds of TeV, with improved angular resolution and a sensitivity in the TeV energy region better by one order of magnitude than the currently operating arrays. In order to cover this wide energy range, three different telescope types are envisaged, with different mirror sizes and focal plane features. In particular, for the highest energies a possible design is a dual-mirror Schwarzschild-Couder optical scheme, with a compact focal plane. A silicon photomultiplier (SiPM) based camera is being proposed as a solution to match the dimensions of the pixel (angular size of ~ 0.17 degrees). INFN is developing a camera demonstrator made by 9 Photo Sensor Modules (PSMs, 64 pixels each, with total coverage 1/4 of the focal plane) equipped with FBK (Fondazione Bruno Kessler, Italy) Near UltraViolet High Fill factor SiPMs and Front-End Electronics (FEE) based on a Target 7 ASIC, a 16 channels fast sampler (up to 2GS/s) with deep buffer, self-trigger and on-demand digitization capabilities specifically developed for this purpose. The pixel dimensions of

The test results of the Silicon Tungsten Tracker of DAMPE

6\times6

A detector module composed of pixellated crystals coupled to SiPM strips

mm

SiPM-based PET module with depth of interaction

^2

HIGH-RESOLUTION TRACKING WITH SILICON STRIP DETECTORS FOR RELATIVISTIC IONS

lead to a very compact design with challenging problems of thermal dissipation. A modular structure, made by copper frames hosting one PSM and the corresponding FEE, has been conceived, with a water cooling system to keep the required working temperature. The actual design, the adopted technical solutions and the achieved results for this demonstrator are presented and discussed.