486 research outputs found
The HPS electromagnetic calorimeter
The Heavy Photon Search experiment (HPS) is searching for a new gauge boson, the so-called âheavy photon.â Through its kinetic mixing with the Standard Model photon, this particle could decay into an electron-positron pair. It would then be detectable as a narrow peak in the invariant mass spectrum of such pairs, or, depending on its lifetime, by a decay downstream of the production target. The HPS experiment is installed in Hall-B of Jefferson Lab. This article presents the design and performance of one of the two detectors of the experiment, the electromagnetic calorimeter, during the runs performed in 2015â2016. The calorimeter's main purpose is to provide a fast trigger and reduce the copious background from electromagnetic processes through matching with a tracking detector. The detector is a homogeneous calorimeter, made of 442 lead-tungstate (PbWO4) scintillating crystals, each read out by an avalanche photodiode coupled to a custom trans-impedance amplifier
PRIMA+: A proton Computed Tomography apparatus
The proton Computed Tomography (pCT) is a medical imaging
method, based on the use of proton beams with kinetic energy of the order of 250 MeV, aimed to directly measure the stopping power distribution of tissues thus improving the present accuracy of treatment planning in hadron therapy. A pCT system should be capable to measure tissue electron density with an accuracy better than 1% and a spatial resolution better than 1 mm. The blurring effect due to multiple Coulomb scattering can be mitigated by single proton tracking technique. As a first step towards pCT the PRIMA+ Collaboration built a prototype capable to carry out a single radiography and a tomographic image of a rotating object. This apparatus includes a silicon microstrip tracker to identify the proton trajectory and a YAG:Ce calorimeter to measure the particle residual energy
Data acquisition system for a proton imaging apparatus
New developments in the proton-therapy field for cancer treatments, leaded Italian physics researchers to realize a proton imaging apparatus consisting of a silicon microstrip tracker to reconstruct the proton trajectories and a calorimeter to measure their residual energy. For clinical requirements, the detectors used and the data acquisition system should be able to sustain about 1 MHz proton rate. The tracker read-out, using an ASICs developed by the collaboration, acquires the signals detector and sends data in parallel to an FPGA. The YAG:Ce calorimeter generates also the global trigger. The data acquisition system and the results obtained in the calibration phase are presented and discussed
Measurement of the atmospheric muon depth intensity relation with the NEMO Phase-2 tower
The results of the analysis of the data collected with the NEMO Phase-2
tower, deployed at 3500 m depth about 80 km off-shore Capo Passero (Italy), are
presented. Cherenkov photons detected with the photomultipliers tubes were used
to reconstruct the tracks of atmospheric muons. Their zenith-angle distribution
was measured and the results compared with Monte Carlo simulations. An
evaluation of the systematic effects due to uncertainties on environmental and
detector parameters is also included. The associated depth intensity relation
was evaluated and compared with previous measurements and theoretical
predictions. With the present analysis, the muon depth intensity relation has
been measured up to 13 km of water equivalent.Comment: submitted to Astroparticle Physic
NEMO: A Project for a km Underwater Detector for Astrophysical Neutrinos in the Mediterranean Sea
The status of the project is described: the activity on long term
characterization of water optical and oceanographic parameters at the Capo
Passero site candidate for the Mediterranean km neutrino telescope; the
feasibility study; the physics performances and underwater technology for the
km; the activity on NEMO Phase 1, a technological demonstrator that has
been deployed at 2000 m depth 25 km offshore Catania; the realization of an
underwater infrastructure at 3500 m depth at the candidate site (NEMO Phase 2).Comment: Proceeding of ISCRA 2006, Erice 20-27 June 200
Measurement of the atmospheric muon flux with the NEMO Phase-1 detector
The NEMO Collaboration installed and operated an underwater detector
including prototypes of the critical elements of a possible underwater km3
neutrino telescope: a four-floor tower (called Mini-Tower) and a Junction Box.
The detector was developed to test some of the main systems of the km3
detector, including the data transmission, the power distribution, the timing
calibration and the acoustic positioning systems as well as to verify the
capabilities of a single tridimensional detection structure to reconstruct muon
tracks. We present results of the analysis of the data collected with the NEMO
Mini-Tower. The position of photomultiplier tubes (PMTs) is determined through
the acoustic position system. Signals detected with PMTs are used to
reconstruct the tracks of atmospheric muons. The angular distribution of
atmospheric muons was measured and results compared with Monte Carlo
simulations.Comment: Astrop. Phys., accepte
QBeRT: An innovative instrument for qualification of particle beam in real-time
This paper describes an innovative beam diagnostic and monitoring system composed of a position sensitive detector and a residual range detector, based on scintillating optical fiber and on an innovative read-out strategy and reconstruction algorithm. The position sensitive detector consists of four layers of pre-aligned and juxtaposed scintillating fibres arranged to form two identical overlying and orthogonal planes. The 500 ÎŒm square section fibres are optically coupled to two Silicon Photomultiplier arrays using a channel reduction system patented by the Istituto Nazionale di Fisica Nucleare. The residual range detector is a stack of sixty parallel layers of the same fibres used in the position detector, each of which is optically coupled to a channel of Silicon Photomultiplier array by wavelength shifting fibres. The sensitive area of the two detectors is 9 Ă 9 cm2. After being fully characterized at CATANA proton therapy facility, the performance of the prototypes was tested during last year also at TIFPA proton irradiation facility. The unique feature of these detectors is the possibility to work in imaging conditions (e.g. a particle at a time up to 106 particles per second) and in therapy conditions up to 109 particles per second. The combined use of the two detectors, in imaging conditions, as an example of application, allows the particle radiography of an object. In therapy conditions, in particular, the system measures the position, the profiles, the energy and the fluence of the beam
Design and characterisation of a real time proton and carbon ion radiography system based on scintillating optical fibres
This paper describes the design and characterization of a charged particle imaging system composed of a position sensitive detector and residual range detector. The position detector consists of two identical overlying and orthogonal planes each of which consists of two layers of pre-aligned and juxtaposed scintillating fibres. The 500â
ÎŒm square section fibres are optically coupled to two Silicon Photomultiplier arrays using a channel reduction system patented by the Istituto Nazionale di Fisica Nucleare. The residual range detector consists of sixty parallel layers of the same fibres used in the position detector each of which is optically coupled to a Silicon Photomultiplier array by wavelength shifting fibres. The sensitive area of the two detectors is 9â
Ăâ
9â
cm 2. Characterising the position sensitive and the residual range detectors to reconstruct the radiography, is fundamental to validating the detectorsâ designs. The proton radiography of a calibrated target in imaging conditions is presented. The spatial resolution of the position sensitive detector is about 150â
ÎŒm and the range resolution is about 170â
ÎŒm. The performance of the prototypes were tested at CATANA proton therapy facility (Laboratori Nazionali del Sud, INFN, Catania) with energy up to 58â
MeV and rate of about 10^6 particles per second. The comparison between the simulations and measurements confirms the validity of this system
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