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The ATLAS Transition Radiation Tracker (TRT) is the outermost of the three sub-systems of the ATLAS Inner Detector at the Large Hadron Collider (LHC) at CERN. It consists of close to 300000 thin-walled drift tubes (straws) providing on average 30 two-dimensional space points with 130 μm resolution for charged particle tracks with |η| <; 2 and pT >; 0.5 GeV. Along with continuous tracking, it...
An experiment to measure the performance of 3-D position-sensitive pixellated HgI2 crystals cooled below room temperature was carried out using a new ASIC from GammaMedica-Ideas. This ASIC is capable of reading out the digitized pre-amplifier signal waveforms of 121 pixels and the cathode. A significant improvement in energy resolution from 1.48% FWHM at 662keV for the whole detector to 1.09% FWHM...
The CSTD project aims at developing a high resolution pixel gamma detector based on CdZnTe for Compton imaging applications. Our research group has been working recently on the design and characterization of a new pixel detector with specifications focused at high energy SPECT for medical imaging applications. The detector pitch, 0.3 mm, and its thickness, 5 mm, allows to reach high spatial resolution...
We are investigating using dual-ended readout of axially-oriented long thin scintillator crystals in detectors for a compact geometry animal PET system. In this work we determine the axial-positioning calibration of a 2 × 2 × 100 mm3 LYSO crystal wrapped in either Teflon or 3M Enhanced Specular Reflector (ESR) readout at either end by position sensitive photomultiplier tubes (PSPMTs). We compare two...
Fully depleted DEPFET active pixel sensors designed for ILC vertex detector were tested at CERN SPS using beams of pions and electrons with energies between 40 and 120 GeV. The sensors tested were 450 μm thick prototypes with pixel size between 20 and 32 μm. The paper presents a brief overview of measurement and analysis, followed by a selection of results focused on detailed in-pixel variation of...
Attempts are made to construct micromegas and PIM-like detectors by using thermo-bond film as frames and spaces to support the woven micromeshes and to maintain the gas gaps. The unsupported spans of the meshes in prototypes that we tested are 2.5 cm to 4.5 cm. This method of micromegas construction does not require the photolithographic process. Prototype construction and test results of the single...
One of the main issues regarding a gaseous detector is the gas flow inside the detector itself. A bad gas flow can affect irreversibly the chamber performance. On the other hand optimizing gas circulation inside the detector could allow a safe and reliable operation even with less gas consumption while at the same time maintaining high performance. Simulations and comparison between several different...
Muon tomography based on the measurement of multiple scattering of atmospheric cosmic ray muons is a promising technique for detecting and imaging heavily shielded high-Z nuclear materials such as enriched uranium. This technique could complement standard radiation detection portals currently deployed at international borders and ports, which are not very sensitive to heavily shielded nuclear materials...
With the first year of successful data taking of proton-proton collisions at LHC, the full chain of the ATLAS Trigger and Data Acquisition System could be tested under real conditions. The trigger monitoring and data quality infrastructure was essential to this success. We describe the software tools used to monitor the trigger system performance, assess the overall quality of the trigger selection...
The position sensitivity in a 3”×3” LaBr3:Ce crystal has been simulated using collimated beams of medium and high energy γ-rays. The simulations have been done using the GEANT4 libraries which allow to follow both the gamma ray interaction in the detector and the scintillation light up to the photocathode. In the simulations the crystal has been coupled to an ideal PSPMT and/or a shielded PMT. The...
The CMS collaboration has developed a fast Monte Carlo simulation of the CMS detector with event production rates ~100 times faster than the GEANT4-based simulation, with comparable accuracy for most of the high level observables to be used in the physics analyses. We discuss basic technical principles of the CMS Fast Simulation and their implementation in the different components of the detector:...
Photo-sensor sharing (multiple blocks or crystals) can achieve high-resolution position-sensitive detectors but it also increases the dead time and pileups for scintillation event detection. Several methods such as pulse-clipping and HYPER (high-yield-pileup-event-recovery) have been introduced to minimize the dead time and pileups with a trade-off of less scintillation light collection. However,...
We developed a method to make GEM foils with a spherical geometry. Tests of this procedure and with the resulting spherical GEMS are presented. Together with a spherical drift electrode, a spherical conversion gap can be formed. This eliminates the parallax error for detection of X-rays, neutrons or UV photons when a gaseous converter is used. This parallax error limits the spatial resolution at wide...
The SuperB asymmetric e+ e- collider has been designed to deliver a luminosity greater than 1036 cm-2 s-1 maintaining moderate beam currents. Comparing to current B-Factories, the reduced center-of-mass boost of the SuperB machine requires an improved vertex resolution to allow precision measurements sensitive to New Physics. Therefore the SuperB Silicon Vertex Tracker will be equipped with an innermost...
In the detection of radiation sources, the combination of spectral and directional information can improve detection over using either one alone. Directional information found through probabilistic Compton-imaging methods helps to distinguish point sources from extended background sources. In this work, we use 3D-position-sensitive CdZn Te detectors to investigate the combination of these data for...
Simulation studies and spectroscopic measurements are presented regarding the development of a pixel multilayer CdTe detector under development in the context of the COCAE project. The instrument will be used for the localization and identification of radioactive sources and radioactively contaminated spots. For the localization task the Compton effect is exploited. The detector response under different...
The High Efficiency Multimode Imager, HEMI, is a combined Compton and coded aperture imager designed to detect, localize, and characterize gamma-ray sources within the energy range from tens of keV to a few MeV. HEMI consists of cubic centimeter CdZnTe detectors with good spectral resolution (~2% at 662 keV) that allow for the separation and identification of discrete gamma-ray energies. This paper...
The NA62 experiment at the CERN Super Proton Synchrotron (SPS) has been proposed with the purpose to measure the Branching Ratio for the ultrarare decay K+ →π+ vv. In order to minimize the multiple scattering of the outgoing pion, it is proposed to operate the magnetic spectrometer in vacuum, upstream of the decay region. This means that the decay region and the spectrometer share a common vaccum...
Gamma ray tracking arrays like AGATA and GRETA are composed of position sensitive segmented HPGe detectors. In fact the gamma interaction localization with a precision of at least 5 mm is an important step to efficiently perform the tracking. This position information is obtained with the combined use of detector electrode segmentation and Pulse Shape Analysis (PSA). In this work a generalized version...
We report on the main design and technological issues related to a modified 3D-DTTC (Double-side, Double-Type-Column) detector process at FBK (Trento, Italy). With respect to the previous versions of this technology, which involved columnar electrodes of both doping types etched from both wafer sides and stopping at a short distance from the opposite surface, passing-through columns are now available...
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