Data encoding efficiency in pixel detector readout with charge information

The average minimum number of bits needed for lossless readout of a pixel detector is calculated, in the regime of interest for particle physics where only a small fraction of pixels have a non-zero value per frame. This permits a systematic comparison of the readout efficiency of different encoding imple- mentations. The calculation is compared to the number of bits used by the FE-I4 pixel readout chip of the ATLAS experiment.Comment: 13 pages, 6 figure

A review of advances in pixel detectors for experiments with high rate and radiation

The Large Hadron Collider (LHC) experiments ATLAS and CMS have established hybrid pixel detectors as the instrument of choice for particle tracking and vertexing in high rate and radiation environments, as they operate close to the LHC interaction points. With the High Luminosity-LHC upgrade now in sight, for which the tracking detectors will be completely replaced, new generations of pixel detectors are being devised. They have to address enormous challenges in terms of data throughput and radiation levels, ionizing and non-ionizing, that harm the sensing and readout parts of pixel detectors alike. Advances in microelectronics and microprocessing technologies now enable large scale detector designs with unprecedented performance in measurement precision (space and time), radiation hard sensors and readout chips, hybridization techniques, lightweight supports, and fully monolithic approaches to meet these challenges. This paper reviews the world-wide effort on these developments.Comment: 84 pages with 46 figures. Review article.For submission to Rep. Prog. Phy

DC to DC Power Conversion

We present results from a capacitor charge pump DC-DC converter prototype using 0.35um HV-CMOS technology fabricated in April 2006. The purpose of this prototype is to test the switch technology both for achievable efficiency and for radiation tolerance. The IC of this test device contains only switches, with all clocks being externally supplied and driven and the capacitors also external. The configuration used is a 4 capacitor stack producing a nominal x4 input current multiplication factor. The goal for this type of device is to be of low enough mass and high enough radiation tolerance to be placed on individual modules in the innermost layers of the Atlas collider detector. Irradiation results will be presented if available. A prototype test card for use with a silicon strip stave prototype is under development

Planar Pixel Sensors for the ATLAS tracker upgrade at HL-LHC

The ATLAS Planar Pixel Sensor R&D Project is a collaboration of 17 institutes and more than 80 scientists. Their goal is to explore the operation of planar pixel sensors for the tracker upgrade at the High Luminosity-Large Hadron Collider (HL-LHC). This work will give a summary of the achievements on radiation studies with n-in-n and n-in-p pixel sensors, bump-bonded to ATLAS FE-I3 and FE-I4 readout chips. The summary includes results from tests with radioactive sources and tracking efficiencies extracted from test beam measurements. Analysis results of ${2\cdot10^{16}} \text{n}_{\text{eq}}\text{cm}^{-2}$ and ${1\cdot10^{16}} \text{n}_{\text{eq}}\text{cm}^{-2}$ ($1 \text{MeV}$ neutron equivalent) irradiated n-in-n and n-in-p modules confirm the operation of planar pixel sensors for future applications

An Application of HEP Track Seeding to Astrophysical Data

We apply methods of particle track reconstruction in High Energy Physics (HEP) to the search for distinct stellar populations in the Milky Way, using the Gaia EDR3 data set. This was motivated by analogies between the 3D space points in HEP detectors and the positions of stars (which are also points in a coordinate space) and the way collections of space points correspond to particle trajectories in the HEP, while collections of stars from distinct populations (such as stellar streams) can resemble tracks. Track reconstruction consists of multiple steps, the first one being seeding. In this note, we describe our implementation and results of the seeding step to the search for distinct stellar populations, and we indicate how the next steps will proceed. Our seeding method uses machine learning tools from the FAISS library, such as the k-nearest neighbors (kNN) search.Comment: 9 pages, 10 figures, 1 table. Conference proceedings preprint for Connecting the Dots (CTD) 2023. Updated figures, fixed typo

Optimal use of Charge Information for the HL-LHC Pixel Detector Readout

The pixel detectors for the High Luminosity upgrades of the ATLAS and CMS detectors will preserve digitized charge information in spite of extremely high hit rates. Both circuit physical size and output bandwidth will limit the number of bits to which charge can be digitized and stored. We therefore study the effect of the number of bits used for digitization and storage on single and multi-particle cluster resolution, efficiency, classification, and particle identification. We show how performance degrades as fewer bits are used to digitize and to store charge. We find that with limited charge information (4 bits), one can achieve near optimal performance on a variety of tasks.Comment: 27 pages, 20 figure