Damien Neyret

This work presents radiation-tolerant implementations for the SALSA front-end readout ASIC through redundancy methods applied to two median-finding algorithms designed for coherent noise suppression. Bit-wise Median Finder (BWMF) and Combinatorial Sum Median Finder (CSMF) were implemented in TSMC 65 nm and evaluated in terms of area, power, and latency. Three redundancy techniques were applied in this work to compare their impact: simple TMR, full TMR, and temporal TMR (TTMR). The simple and full TMR approach was applied in both algorithms to establish comparisons and TTMR was applied to CSMF as an improvement. The results indicate that the BWMF achieves efficient performance in terms of area and power under the simple TMR scheme, but exhibits significantly higher power consumption when using the more robust full TMR approach. The TTMR technique, in turn, offers reliable fault tolerance while maintaining a feasible balance between area and power.

In 2022, the COMPASS collaboration performed semi-inclusive measurements of deep-inelastic muon-scattering on a transversely polarised deuteron (6LiD) target. From these data, transverse-spin-dependent dihadron asymmetries are extracted using pairs of oppositely charged hadrons. These asymmetries are directly sensitive to the quark transversity distributions and provide an independent handle on these fundamental quantities with respect to the Collins asymmetries measured in single-hadron production. The present results significantly improve upon the previous COMPASS deuteron measurements, which were the only available deuteron data worldwide, and reach a statistical precision comparable to that of the existing proton results from COMPASS. A small but nonzero asymmetry is observed at large Bjorken-x, consistent with theoretical expectations. A point-by-point extraction of the valence-quark transversity distributions yields, in particular, a substantially improved determination of the d-quark transversity. These measurements represent a major step towards a complete flavour mapping of the transverse-spin structure of the nucleon.

The multiplicities of positive and negative pions, kaons, and unidentified hadrons produced in deep-inelastic scattering are measured in bins of the Bjorken scaling variable x , the relative virtual-photon energy y , and the fraction of the virtual-photon energy transferred to the final-state hadron z . Data were obtained by the COMPASS Collaboration using a 160 GeV muon beam of both electric charges and a liquid hydrogen target. These measurements cover the kinematic domain with photon virtuality Q 2 > 1 ( GeV / c ) 2 , 0.004 < x < 0.4 , 0.1 < y < 0.7 , and 0.2 < z < 0.85 , in accordance with the kinematic domain used in earlier published COMPASS multiplicity measurements with an isoscalar target. The calculation of radiative corrections was improved by using the Monte Carlo generator , which results in up to 12% larger corrections in the low- x region.

The SALSA chip is a future readout ASIC foreseen for the MPGD detectors, developed in the framework of the EIC collider project, to equip the MPGD trackers of the EPIC experiment. It is designed to be versatile, to be adapted to other usages of MPGD detectors like TPC or photon detectors. It integrates a frontend block and an ADC for each of the 64 channels, associated to a configurable DSP processor meant to correct data and reduce the raw data flux to limit the output bandwidth. It will be compatible with the continuous readout foreseen for the EPIC DAQ, but will also work in a triggered environment. Several prototypes are already produced in order to qualify the different blocks of the chip, in particular the frontend, the ADC and the clock generation. The next 32-channel prototype is currently under development and is planed to be produced in 2025. The final prototype will be produced and tested from 2026 for a production of the SALSA chip at the horizon of 2027.