Abstract Proton therapy requires range verification in order to exploit its full potential. One of the most promising approaches is to monitor prompt gamma-rays produced by nuclear interactions of ...the therapeutic particles in the patient tissues. A detector with a wide energy range from 100 keV to 15 MeV and excellent time resolution is required to achieve millimetric precision in proton range. During patient treatment, the detector count rates are usually above 10 6 s -1 and the fraction of pile-up events is very high for commonly used fast inorganic scintillators. We are investigating a full acceptance approach with increased granularity in order to reduce the size of the scintillators and consequently the count rate per channel. Stacking the scintillators in matrices requires suitable multi-channel photo-multipliers and a fitting acquisition system. Here, we present two geometries of CeBr 3 crystals 5×5×20 mm 3 and 10×10×30 mm 3 , together with modern silicon photo-multipliers (SiPM) adapted to work with the PETsys TOFPET2 ASIC. The TOFPET2 ASIC was developed for Time-of-Flight Positron Emission Tomography (TOF-PET) applications. Here we show its potential for higher gamma-ray energies and future hybrid imaging. First results of energy resolution of 6.1%–7.8% are achieved at 3.42 MeV using a 241 Am 9 Be source. The time resolution was found to be below 100 ps and studies of the count rates and the dead time of the full system were performed. Different SiPM models are analysed for their impact on the coincidence time resolution.
The Compact Muon Solenoid (CMS) is one of the two large, general purpose experiments situated at the LHC at CERN. As with all high energy physics experiments, knowledge of the beam conditions and ...luminosity is of vital importance.
The Beam Conditions and Radiation Monitoring System (BRM) is installed in CMS to protect the detector and to provide feedback to LHC on beam conditions. It is composed of several sub-systems that measure the radiation level close to or inside all sub-detectors, monitor the beam halo conditions with different time resolution, support beam tuning and protect CMS in case of adverse beam conditions by firing a beam abort signal. This paper presents three of the BRM subsystems: the Fast Beam Conditions Monitor (BCM1F), which is designed for fast flux monitoring, measuring with nanosecond time resolution, both the beam halo and collision products; the Beam Scintillator Counters (BSC), that provide hit rates and time information of beam halo and collision products; and the Beam Conditions Monitors (BCM) used as a protection system that can trigger a beam dump when beam losses occur in order to prevent damage to the pixel and tracker detectors. A description of the systems and a characterization on the basis of data collected during LHC operation is presented.
The Beam Conditions and Radiation Monitoring System (BRM), is installed in CMS to protect the CMS detector from high beam losses and to provide feedback to the LHC and CMS on the beam conditions. The ...primary detector subsystems are based on either single crystal diamond sensors (BCM1F) for particle counting with nanosecond resolution or on polycrystalline diamonds (BCM2; BCM1L) for integrated signal current measurements. Beam scintillation counters (BSC) are also used during low luminosity running. The detectors have radiation hard front-end electronics and are read out independently of the CMS central data acquisition and are online whenever there is beam in the LHC machine. The various sub-systems exploit different time resolutions and position locations to be able to monitor the beam induced backgrounds and the flux of particles produced during collisions. This paper describes the CMS BRM system and the complementary aspects of the installed BRM sub-detectors to measure both single particle count rates and signal currents originating from beam backgrounds and collision products in CMS.
The ATLAS transition radiation tracker Boldyrev, A. S.; Bondarenko, V. G.; Bychkov, V. N. ...
Instruments and experimental techniques (New York),
05/2012, Letnik:
55, Številka:
3
Journal Article
Recenzirano
The transition radiation tracker of the ATLAS setup, which is one of the two multipurpose detectors at the Large Hadron Collider (LHC), its design, and the tasks it performs are described. The ...tracker is fully assembled and commissioned. The first physical results obtained by the tracker in the ATLAS cosmic muon runs are presented.
LumiCal will be the luminosity calorimeter for the proposed International Large Detector of the International Linear Collider (ILC). The ILC physics program requires the integrated luminosity to be ...measured with a relative precision on the order of 10e-3, or 10e-4 when running in GigaZ mode. Luminosity will be determined by counting Bhabha scattering events coincident in the two calorimeter modules placed symmetrically on opposite sides of the interaction point. To meet these goals, the energy resolution of the calorimeter must be better than 1.5% at high energies. LumiCal has been designed as a 30-layer sampling calorimeter with tungsten as the passive material and silicon as the active material. Monte Carlo simulation using the Geant4 software framework has been used to identify design elements which adversely impact energy resolution and correct for them without loss of statistics. BeamCal, covering polar angles smaller than LumiCal, will serve for beam tuning, luminosity optimisation and high energy electron detection. Secondly, prototypes of the sensors and electronics for both detectors have been evaluated during beam tests, the results of which are also presented here.
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