arXiv subjects

Werner Lustermann

Publications and source records attributed to Werner Lustermann.

3 recordsLinked to original sources

arXiv2026

CMS ECAL Phase-2 upgrade: characterisation and stability analysis of a three-stage low-voltage power-conversion system

As part of the High-Luminosity upgrade of the Large Hadron Collider, the front-end electronics of the Compact Muon Solenoid electromagnetic calorimeter barrel are being replaced. A three-stage low-voltage power-conversion system supplies the upgraded electronics. As the cascade dynamics require characterisation to ensure stable operation, interactions between the three converter stages are assessed at their two interfaces using the Nyquist criterion. A validated shunt-injection setup using a Bode 100 frequency-response analyser provides in-situ impedance measurements under load to assess the accuracy of the averaged converter models. Results show that both interfaces are stable over the evaluated configurations, with modelled minimum distances to the critical point of 0.76 and 0.79, respectively. A turn-on study identifies capacitor charging at Stage 3 as the main cause of inrush currents triggering Stage 2 overcurrent protection. Two Stage 3 board variants stagger converter enables within and between boards, keeping the measured two-tower current below 5 A, within the 8.0 A protection threshold.

physics.ins-det↗

arXiv2025

Radiation Testing of New Readout Electronics for the CMS ECAL Barrel

In preparation of the operation of the CMS electromagnetic calorimeter (ECAL) barrel at the High Luminosity Large Hadron Collider (HL-LHC) the entire on-detector electronics will be replaced. The new readout electronics comprises 12240 very front end (VFE), 2448 front end (FE) and low voltage regulator (LVR) cards arranged into readout towers (RTs) of five VFEs, one FE and one LVR card. The results of testing one RT of final prototype cards at CERNs CHARM mixed field facility and PSIs proton irradiation facility are presented. They demonstrate the proper functioning of the new electronics in the expected radiation conditions.

hep-ex↗

arXiv2016

Real-Time Computation of Parameter Fitting and Image Reconstruction Using Graphical Processing Units

In recent years graphical processing units (GPUs) have become a powerful tool in scientific computing. Their potential to speed up highly parallel applications brings the power of high performance computing to a wider range of users. However, programming these devices and integrating their use in existing applications is still a challenging task. In this paper we examined the potential of GPUs for two different applications. The first application, created at Paul Scherrer Institut (PSI), is used for parameter fitting during data analysis of muSR (muon spin rotation, relaxation and resonance) experiments. The second application, developed at ETH, is used for PET (Positron Emission Tomography) image reconstruction and analysis. Applications currently in use were examined to identify parts of the algorithms in need of optimization. Efficient GPU kernels were created in order to allow applications to use a GPU, to speed up the previously identified parts. Benchmarking tests were performed in order to measure the achieved speedup During this work, we focused on single GPU systems to show that real time data analysis of these problems can be achieved without the need for large computing clusters. The results show that the currently used application for parameter fitting, which uses OpenMP to parallelize calculations over multiple CPU cores, can be accelerated around 40 times through the use of a GPU. The speedup may vary depending on the size and complexity of the problem. For PET image analysis, the obtained speedups of the GPU version was more than x40 larger compared to a single core CPU implementation. The achieved results show that it is possible to improve the execution time by orders of magnitude.

cs.DC↗