C. Civinini

Hadron calorimetry in the L3 detector

Abstract The characteristics of the L3 hadron calorimeter as realized in the observation of hadronic jets and other events from e + e − collisions at LEP are presented and discussed. The pattern-recognition algorithm utilizing the fine granulatiry of the calorimeter is described, and the observed overall resolution of 10.2% for hadron jets from Z decay is reported. The use of the calorimeter in providing information on muon energy losses is also noted.

Characterization of a Silicon Strip Detector and a YAG:Ce Calorimeter for a Proton Computed Radiography Apparatus

Today, there is a steadily growing interest in the use of proton beams for tumor therapy, as they permit to tightly shape the dose delivered to the target reducing the exposure of the surrounding healthy tissues. Nonetheless, accuracy in the determination of the dose distribution in proton-therapy is up to now limited by the uncertainty in stopping powers, which are presently calculated from the photon attenuation coefficients measured by X-ray tomography. Proton computed tomography apparatus (pCT) has been proposed to directly measure the stopping power and reduce this uncertainty. Main problem with proton imaging is the blurring effect introduced by multiple Coulomb scattering: single proton tracking is a promising technique to face this difficulty. As a first step towards a pCT system, we designed a proton radiography (pCR) prototype based on a silicon microstrip tracker (to characterize particle trajectories) and a segmented YAG:Ce calorimeter (to measure their residual energy). Aim of the system is to detect protons with a ~1 MHz particle rate of and with kinetic energy in the range 250-270 MeV, high enough to pass through human body. Design and development of the pCR prototype, as well as the characterization of its single components, are described in this paper.

A proton Computed Tomography system for medical applications

Proton Computed Tomography (pCT) can improve the accuracy of both patient positioning and dose calculation in proton therapy, enabling to accurately reconstruct the electron density distribution of irradiated tissues. A pCT prototype, equipped with a silicon tracker and a YAG:Ce calorimeter, has been manufactured by an Italian collaboration. First tests under proton beam allowed obtaining good quality tomographic images of a non-homogeneous phantom. Manufacturing of a new large area system with real-time data acquisition is under way.

Beam test results for single- and double-sided silicon detector prototypes of the CMS central detector

We report the results of two beam tests performed in July and September 1995 at CERN using silicon microstrip detectors of various types: single sided, double sided with small angle stereo strips, double sided with orthogonal strips, double sided with pads. For the read-out electronics use was made of Preshape32, Premux128 and VA1 chips. The signal to noise ratio and the resolution of the detectors was studied for different incident angles of the incoming particles and for different values of the detector bias voltage. The goal of these tests was to check and improve the performances of the prototypes for the CMS Central Detector.

Ceramic PPC technology and performance

Abstract Mass production technology for PPCs (Parallel Plate Chambers) is described. This technology provides a precise manufacture of chamber components and a high uniformity of chamber properties. Only radiation hard materials were used. Results on the chamber uniformity, the detection efficiency and the timing properties of PPCs are presented.

A proton Computed Tomography based medical imaging system

This paper reports on the activity of the INFN PRIMA/RDH collaboration in the development of proton Computed Tomography (pCT) systems based on single proton tracking and residual energy measurement. The systems are made of a silicon microstrip tracker and a YAG:Ce crystal calorimeter to measure single protons trajectory and residual energy, respectively. A first prototype of pCT scanner, with an active area of about 5 × 5 cm2 and a data rate capability of 10 kHz, has been constructed and characterized with 62 MeV protons at INFN Laboratori Nazionali del Sud in Catania (Italy) and with 180 MeV protons at The Svedberg Laboratory (TSL) in Uppsala (Sweden). Results of these measurements, including tomographic reconstructions of test phantoms, will be shown and discussed. An upgraded system with an extended field of view (up to ~ 5 × 20 cm2) and an increased event rate capability up to one MHz, presently under development, will be also described.

Parallel plate chambers: a fast detector for ionizing particles

Abstract The parallel plate chamber technique is summarized together with recent results of tests concerning efficiency, time resolution, high rate capability and radiation resistance.

Study of radiation damage and substrate resistivity effects from beam test of silicon microstrip detectors using LHC readout electronics

Abstract We present the beam test results of single-sided silicon microstrip detectors, with different substrate resistivities. The effects of radiation damage are studied for a detector irradiated to a fluence of 2.4×10 14 n / cm 2 . The detectors are read out with the APV6 chip, which is compatible with the 40 MHz LHC clock. The performance of different detectors and readout modes are studied in terms of signal-to-noise ratio and efficiency.

A data acquisition system for silicon microstrip detectors

Following initial work done by some of us on the readout of the L3 silicon microvertex detector, we have developed a complete data acquisition system for silicon microstrip detectors for use both in our home institute and at the various test beam facilities at the CERN laboratory. The system uses extensive decoupling schemes allowing a fully floating connection to the detector. This feature has many advantages especially in the readout of the latest double-sided silicon microstrip detectors.

Design and characterisation of a YAG(Ce) calorimeter for proton Computed Tomography application

The design and the characterization of a calorimeter system, aimed at measuring the residual energy in a proton Computed Tomography (pCT) apparatus, is described. The calorimeter has a 6 × 6 cm2 active area to fully cover the tracker area of the pCT system, being 10 cm thick it is able to stop up to 200 MeV protons and sustain 1 MHz particle rate (average rate on the whole area). The YAG(Ce) scintillator is promising for charged particle detection applications where high-count rate, good energy resolution and compact photodiode readout, not influenced by magnetic fields, are of importance. The aim of this work is to show data acquired with proton beam energy up to 175 MeV and to discuss the performances of this calorimeter.