Depleted Monolithic Active Pixel Sensors (DMAPS) are monolithic pixel detectors with high-resistivity substrates designed for use in high-rate and high-radiation environments. They are produced in ...commercial CMOS processes, resulting in relatively low production costs and short turnaround times, and offer a low material budget. LF-Monopix1 and TJ-Monopix1 are large DMAPS prototypes produced in 150 nm LFoundry and 180 nm TowerJazz technology, respectively, that follow two different design concepts regarding the charge collection electrode. Prototypes of both development lines have been extensively tested and characterized over the last years. The second-generation Monopix prototypes, Monopix2, were recently produced. They were designed to address the shortcomings of their predecessors, in particular related to radiation hardness and cross talk, and further improve upon their performance. The latest measurements with LF-Monopix1 and TJ-Monopix1 concerning hit efficiency, depletion, and radiation hardness as well as the initial test results of the new Monopix2 prototypes are presented.
DMAPS Monopix developments in large and small electrode designs Bespin, C.; Barbero, M.; Barrillon, P. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
10/2020, Letnik:
978
Journal Article
Recenzirano
Odprti dostop
LF-Monopix1 and TJ-Monopix1 are depleted monolithic active pixel sensors (DMAPS) in 150nm LFoundry and 180nm TowerJazz CMOS technologies respectively. They are designed for usage in high-rate and ...high-radiation environments such as the ATLAS Inner Tracker at the High-Luminosity Large Hadron Collider (HL-LHC). Both chips are read out using a column-drain readout architecture. LF-Monopix1 follows a design with large charge collection electrode where readout electronics are placed inside. Generally, this offers a homogeneous electrical field in the sensor and short drift distances. TJ-Monopix1 employs a small charge collection electrode with readout electronics separated from the electrode and an additional n-type implant to achieve full depletion of the sensitive volume. This approach offers a low sensor capacitance and therefore low noise and is typically implemented with small pixel size. Both detectors have been characterized before and after irradiation using lab tests and particle beams.
A shunt regulator was designed to meet the specifications for the serial powering of the CMOS pixel detector modules in compatibility with the next upgrade of the ATLAS detector. Serial powering ...greatly increases the system's power efficiency when compared to a parallel powering scheme and allows for significant material budget savings in the power cabling. In such a scheme, each pixel detector chip is powered by a shunt regulator that takes in a constant current and produces a regulated output voltage relative to the module's potential ground. The proposed regulator has a modular structure. Each regulator module consists of a shunt regulation submodule followed by a low-dropout voltage regulation submodule and is designed to deliver a nominal output current of 10 mA. The regulator module's schematic is presented along with a theoretical study and stability analysis. A test chip was designed in the 0.18-<inline-formula> <tex-math notation="LaTeX">\mu \text{m} </tex-math></inline-formula> CMOS technology containing one main shunt regulator composed of 126 modules, as well as two separate regulators each composed of one single module. The characterization measurements show a correct dc startup for various load conditions, as expected by simulations. The output voltage of a single module is regulated with a precision <1%. Moreover, the regulator module works with a low voltage dropout of 200 mV for a large range of input current from 3 to 18 mA. The equivalent series resistance of a 40-module regulator is measured to be 15 <inline-formula> <tex-math notation="LaTeX">\text{m}\Omega </tex-math></inline-formula>, including the wire bonding and test bench parasitics. The test chip is successfully tested in the serial mode and in the parallel mode. In the latter mode, the current mismatch between the parallel chips is measured to be less than 3.4% for an input current of 1 A. Moreover, transient measurements performed with an active load show proper functioning with no undershoots or overshoots. Finally, the test chip was irradiated with an X-ray source up to 125 Mrad. Measurements show a stable response of the regulator with an intrinsic output voltage variation of less than 1%.
The characterization of a PET detector head based on continuous LYSO crystals and silicon photomultiplier (SiPM) arrays as photodetectors has been carried out for its use in the development of a ...small animal PET prototype. The detector heads are composed of a continuous crystal and a SiPM matrix with 64 pixels in a common substrate, fabricated specifically for this project. Three crystals of 12 mm × 12 mm × 5 mm size with different types of painting have been tested: white, black and black on the sides but white on the back of the crystal. The best energy resolution, obtained with the white crystal, is 16% FWHM. The detector response is linear up to 1275 keV. Tests with different position determination algorithms have been carried out with the three crystals. The spatial resolution obtained with the center of gravity algorithm is around 0.9 mm FWHM for the three crystals. As expected, the use of this algorithm results in the displacement of the reconstructed position toward the center of the crystal, more pronounced in the case of the white crystal. A maximum likelihood algorithm has been tested that can reconstruct correctly the interaction position of the photons also in the case of the white crystal.
The EUSO@TurLab project aims at performing experiments to reproduce Earth UV emissions as seen from a low Earth orbit by the planned missions of the JEM-EUSO program. It makes use of the TurLab ...facility, which is a laboratory, equipped with a 5 m diameter and 1 m depth rotating tank, located at the Physics Department of the University of Turin. All the experiments are designed and performed based on simulations of the expected response of the detectors to be flown in space. In April 2016 the TUS detector and more recently in October 2019 the Mini-EUSO experiment, both part of the JEM-EUSO program, have been placed in orbit to map the UV Earth emissions. It is, therefore, now possible to compare the replicas performed at TurLab with the actual images detected in space to understand the level of fidelity in terms of reproduction of the expected signals. We show that the laboratory tests reproduce at the order of magnitude level the measurements from space in terms of spatial extension and time duration of the emitted UV light, as well as the intensity in terms of expected counts per pixel per unit time when atmospheric transient events, diffuse nightlow background light, and artificial light sources are considered. Therefore, TurLab is found to be a very useful facility for testing the acquisition logic of the detectors of the present and future missions of the JEM-EUSO program and beyond in order to reproduce atmospheric signals in the laboratory.
ATLAS ALFA—measuring absolute luminosity with scintillating fibres Franz, S.; Barrillon, P.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment,
2009, Letnik:
610, Številka:
1
Journal Article, Conference Proceeding
Recenzirano
ALFA is a high-precision scintillating fibre tracking detector under construction for the absolute determination of the LHC luminosity at the ATLAS interaction point. This detector, mounted in ...so-called Roman Pots, will track protons elastically scattered under μrad angles at IP1.In total there are four pairs of vertically arranged detector modules which approach the LHC beam axis to mm distance. Each detector module consists of ten layers of two times 64 scintillating fibres each (U and V planes). The fibres are coupled to 64 channels Multi-Anodes PhotoMultipliers Tubes read out by compact front-end electronics. Each detector module is complemented by so-called overlap detectors: Three layers of two times 30 scintillating fibres which will be used to measure the relative positioning of two vertically arranged main detectors. The total number of channels is about 15000. Conventional plastic scintillator tiles are mounted in front of the fibre detectors and will serve as trigger counter. The extremely restricted space inside the pots makes the coupling to the read out devices very challenging. Several technologies have been tested in a beam at DESY and a cosmic-ray setup at CERN. A possible upgrade of the photo detection could consist in the replacement of the PMT by Geiger-mode avalanche photodiodes. Preliminary tests are being performed comparing the performance of these devices with the ones of the PMTs.
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