67 research outputs found
Monolithic MHz-frame rate digital SiPM-IC with sub-100 ps precision and 70m pixel pitch
This paper presents the design and characterization of a monolithic
integrated circuit (IC) including digital silicon photomultipliers (dSiPMs)
arranged in a 3232 pixel matrix at 70m pitch. The IC provides
per-quadrant time stamping and hit-map readout, and is fabricated in a standard
150-nm CMOS technology. Each dSiPM pixel consists of four single-photon
avalanche diodes (SPADs) sharing a quenching and subsequent processing
circuitry and has a fill factor of 30. A sub-100ps precision, 12-bit
time-to-digital converter (TDC) provides timestamps per quadrant with an
acquisition rate of 3MHz. Together with the hit map, the total sustained
data throughput of the IC amounts to 4Gbps. Measurements obtained in a dark,
temperature-stable environment as well as by using a pulsed laser environment
show the full dSiPM-IC functionality. The dark-count rate (DCR) as function of
the overvoltage and temperature, the TDC resolution, differential and integral
nonlinearity (DNL/INL) as well as the propagation-delay variations across the
matrix are presented. With aid of additional peripheral test structures, the
main building blocks are characterized and key parameters are presented.Comment: 16 pages, 13 figures, 1 tabl
Direct Determination of Hubble Parameter Using Type IIn Supernovae
We introduce a novel approach, a Dense Shell Method (DSM), for measuring
distances for cosmology. It is based on original Baade idea to relate absolute
difference of photospheric radii with photospheric velocity. We demonstrate
that this idea works: the new method does not rely on the Cosmic Distance
Ladder and gives satisfactory results for the most luminous Type IIn
Supernovae. This allows one to make them good primary distance indicators for
cosmology. Fixing correction factors for illustration, we obtain with this
method the median distance of 68^{+19}_{-15} (68%CL) Mpc to SN 2006gy and
median Hubble parameter 79^{+23}_{-17} (68%CL) km/s/Mpc.Comment: 6 pages, 1 figure, typos correcte
Test beam performance of a CBC3-based mini-module for the Phase-2 CMS Outer Tracker before and after neutron irradiation
The Large Hadron Collider (LHC) at CERN will undergo major upgrades to increase the instantaneous luminosity up to 5–7.5×10 cms. This High Luminosity upgrade of the LHC (HL-LHC) will deliver a total of 3000–4000 fb-1 of proton-proton collisions at a center-of-mass energy of 13–14 TeV. To cope with these challenging environmental conditions, the strip tracker of the CMS experiment will be upgraded using modules with two closely-spaced silicon sensors to provide information to include tracking in the Level-1 trigger selection. This paper describes the performance, in a test beam experiment, of the first prototype module based on the final version of the CMS Binary Chip front-end ASIC before and after the module was irradiated with neutrons. Results demonstrate that the prototype module satisfies the requirements, providing efficient tracking information, after being irradiated with a total fluence comparable to the one expected through the lifetime of the experiment
Evaluation of planar silicon pixel sensors with the RD53A readout chip for the Phase-2 Upgrade of the CMS Inner Tracker
The Large Hadron Collider at CERN will undergo an upgrade in order to increase its luminosity to 7.5 × 10³⁴ cm⁻²s⁻¹. The increased luminosity during this High-Luminosity running phase, starting around 2029, means a higher rate of proton-proton interactions, hence a larger ionizing dose and particle fluence for the detectors. The current tracking system of the CMS experiment will be fully replaced in order to cope with the new operating conditions. Prototype planar pixel sensors for the CMS Inner Tracker with square 50 μm × 50 μm and rectangular 100 μm × 25 μm pixels read out by the RD53A chip were characterized in the lab and at the DESY-II testbeam facility in order to identify designs that meet the requirements of CMS during the High-Luminosity running phase. A spatial resolution of approximately 3.4 μm (2 μm) is obtained using the modules with 50 μm × 50 μm (100 μm × 25 μm) pixels at the optimal angle of incidence before irradiation. After irradiation to a 1 MeV neutron equivalent fluence of Φeq = 5.3 × 10¹⁵ cm⁻², a resolution of 9.4 μm is achieved at a bias voltage of 800 V using a module with 50 μm × 50 μm pixel size. All modules retain a hit efficiency in excess of 99% after irradiation to fluences up to 2.1 × 10¹⁶ cm⁻². Further studies of the electrical properties of the modules, especially crosstalk, are also presented in this paper
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