24375634
Spherical gems for parallax-free detectors
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 would eliminate 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 scattering angles. The method is inexpensive and flexible towards possible changes in the design. We show advanced plans to make a prototype of an entirely spherical triple-gem detector, including a spherical readout structure. This detector will have a superior position resolution, also at wide angles, and a high rate capability. A completely spherical gaseous detector has never been made before.
116847052
The LHCb RICH PMTs Readout Electronics and the Monitoring of the HPDs Quantum Efficiency
120117699
Latest results of the R&D on CMOS MAPS for the Layer0 of the SuperB SVT
Physics and high background conditions set very challenging requirements on readout speed, material budget and resolution for the innermost layer of the SuperB Silicon Vertex Tracker operated at the full luminosity. Monolithic Active Pixel Sensors (MAPS) are very appealing in this application since the thin sensitive region allows grinding the substrate to tens of microns. Deep N-Well MAPS, developed in the ST 130 nm CMOS technology, achieved in-pixel sparsification and fast time stamping. Further improvements are being explored with an intense R&D program, including both vertical integration and 2D MAPS with the INMAPS quadruple well. We present the results of the characterization with IR laser, radioactive sources and beam of several chips produced with the 3D (Chartered/Tezzaron) process. We have also studied prototypes exploiting the features of the quadruple well and the high resistivity epitaxial layer of the INMAPS 180 nm process. Promising results from an irradiation campaign with neutrons on small matrices and other test-structures, as well as the response of the sensors to high energy charged tracks are presented.
122515004
The Electromagnetic calorimeter for the OBELIX experiment
Abstract We describe the electromagnetic calorimeter of the OBELIX detector installed on the LEAR facility at CERN: the criteria followed to design its structure and the tests and preparation work performed on the different components are discussed, to conclude with the description of the main control procedures operating on the assembled detector during the first tests of the apparatus on the LEAR beam.
119270544
Analysis and correction of the magnetic field effects in the Hybrid Photo-Detectors of the RICH2 Ring Imaging Cherenkov detector of LHCb.
The Ring Imaging Cherenkov detectors of the LHCb experiment at the Large Hadron Collider at CERN are equipped with Hybrid Photo-Detectors. These vacuum photo-detectors are affected by the stray magnetic field of the LHCb magnet, which degrades their imaging properties. This effect increases the error on the Cherenkov angle measurement and would reduce the particle identification capabilities of LHCb. A system has been developed for the RICH2 Ring Imaging Cherenkov detector to perform a detailed characterisation of the magnetic distortion effects. It is described, along with the methods implemented to correct for these effects, restoring the optimal resolution.
109848273
The high-voltage monitor system for the calorimeter of the OBELIX experiment
Abstract We describe the monitor system developed to manage the high voltage power supply for the electromagnetic calorimeter of the OBELIX experiment, installed on the LEAR facility at CERN. The hardware and software characteristics of the system are discussed, as well as the performance of the same.
108445039
Development of deep N-well monolithic active pixel sensors in a 0.13 mu m CMOS technology
Abstract By exploiting the triple-well option available in a deep-submicron CMOS process, we developed monolithic active pixel sensors (MAPS) with the unique features of full analog signal processing and digital functionality implemented at the pixel level. After briefly reviewing the results achieved with the first prototype chip, we report on the extensive measurements on the second prototype, containing both single-channel sensors, with an improved noise figure, and an 8 × 8 pixel array. For the pixel having a collecting electrode area of 900 μ m 2 we measured an equivalent noise charge of about 40 electrons. Using the Fe 55 5.9 keV line, we obtained a Signal-to-noise (S/N) ratio of about 30. The pixel matrix ( 50 × 50 μ m 2 ) has been successfully readout up to 30 MHz. Through noise scans, an expected significant threshold dispersion has been measured. The measurements presented in this paper confirm the capability of our MAPS, based on the deep n-well concept, to be operated as ionizing radiation detectors and suggest a series of improvements we are already implementing in the design of the next prototype chip.