arXiv subjects

Timon Heim

Publications and source records attributed to Timon Heim.

9 recordsLinked to original sources

arXiv2026

Energy-resolved measurement of individual GeV muon tracks generated by electrons from a compact Laser-Plasma Accelerator

Recently, the possibility of LPA-produced muon beams has gained significant interest within the accelerator application community. Directional, multi-GeV muons can be produced via Bethe-Heitler interactions when multi-GeV electrons hit solid targets. They are highly penetrating and, thanks to the compactness of the LPA, offer a path toward a deployable, active muon source. At the BELLA Center of the Lawrence Berkeley National Laboratory, we previously unambiguously detected muons generated during the interaction of multi-GeV electron beams with a 4 meter-thick electron beam dump. A new campaign has now extended our diagnostic capabilities to single-muon trajectory reconstruction and energy measurements. The setup allowed us to individually reconstruct each muon trajectory, defined by us as a muon passing through three detectors used for the reconstruction. For a subset of events, we extracted the muon energy from the magnetic-field bending angle, demonstrating production of GeV-scale muons. This work provides a key demonstration of track-based active-source muography, which enables non-invasive 3D density mapping of concealed or inaccessible samples, and it will accelerate the development of active LPA-based muon sources where compactness, controlled directionality, low divergence, and deep penetration are required.

physics.acc-ph↗

arXiv2026

Machine Learning on Heterogeneous, Edge, and Quantum Hardware for Particle Physics (ML-HEQUPP)

The next generation of particle physics experiments will face a new era of challenges in data acquisition, due to unprecedented data rates and volumes along with extreme environments and operational constraints. Harnessing this data for scientific discovery demands real-time inference and decision-making, intelligent data reduction, and efficient processing architectures beyond current capabilities. Crucial to the success of this experimental paradigm are several emerging technologies, such as artificial intelligence and machine learning (AI/ML), silicon microelectronics, and the advent of quantum algorithms and processing. Their intersection includes areas of research such as low-power and low-latency devices for edge computing, heterogeneous accelerator systems, reconfigurable hardware, novel codesign and synthesis strategies, readout for cryogenic or high-radiation environments, and analog computing. This white paper presents a community-driven vision to identify and prioritize research and development opportunities in hardware-based ML systems and corresponding physics applications, contributing towards a successful transition to the new data frontier of fundamental science.

physics.ins-det↗

arXiv2025

Testing the limits of ITkPixV2: the ATLAS inner tracker pixel detector readout chip

The ITkPixV2 chip is the final production readout chip for the ATLAS Phase 2 Inner Tracker (ITk) upgrade at the upcoming High-Luminosity LHC (HL-LHC). Due to the extraordinarily high peak luminosity at the HL-LHC of $5 \times 10^{34}$ cm$^{-1}$s$^{-1}$, ITkPixV2 must meet significant increases in nearly all design requirements compared to the current ATLAS Inner Detector (ID), including a 10x increase in trigger rate, a 7.5x increase in hit rate, a 3x increase in radiation tolerance, and a 12.5x decrease in pixel current draw per unit area, all while maintaining a similar power per unit area as present pixel detectors. Here we present the first measurements of the ITkPixV2 chip operated at the limits of the full chip design requirements, including in particular a measurement of the activity-induced current of the chip as a function of increasing hit rate.

physics.ins-det↗

arXiv2024

Measurement of directional muon beams generated at the Berkeley Lab Laser Accelerator

We present the detection of directional muon beams produced using a PW laser at the Lawrence Berkeley National Laboratory. The muon source is a multi-GeV electron beam generated in a 30 cm laser plasma accelerator interacting with a high-Z converter target. The GeV photons resulting from the interaction are converted into a high-flux, directional muon beam via pair production. By employing scintillators to capture delayed events, we were able to identify the produced muons and characterize the source. Using theoretical knowledge of the muon production process combined with simulations that are in excellent agreement with the experiments, we demonstrate that the multi-GeV electron beams produce GeV-scale muons in numbers far exceeding those from cosmic background. Laser-plasma-accelerator-based muon sources can therefore enhance muon imaging applications thanks to their compactness, directionality, and high yields, which reduce the exposure time by orders of magnitude compared to cosmic ray muons. Using the Geant4-based simulation code we developed to gain insight into the experimental results, we can design future experiments and applications based on LPA-generated muons.

physics.acc-ph↗

arXiv2024

Dose rate dependence of TID damage to 65 nm CMOS transistors in X-ray irradiations of the ATLAS ITk Pixel ASIC (ITkPix)

The ATLAS Inner Tracker (ITk) upgrade for the High-Luminosity LHC (HL-LHC) requires a radiation-tolerant pixel readout chip, which must withstand a total ionising dose (TID) of up to 1 Grad. The readout ASIC for the ITk upgrade has been designed by the RD53 collaboration using 65 nm CMOS technology. In order to characterise the radiation tolerance of the chip digital logic, the RD53 ASICs include ring oscillators, which can be used to measure gate delay degradation. Extensive X-ray irradiation studies of the ring oscillators have been performed on the ITk Pixel pre-production readout ASIC, ITkPixV1. A dependence of radiation damage on dose rate has been observed in 65 nm CMOS technology. This paper aims to quantify the dose rate dependence of TID damage to the ITkPix ring oscillators and, therefore, the ITkPix ASIC digital logic. X-ray irradiations at different dose rates between 20 krad/h and 30 Mrad/h are compared. A dose rate dependence is observed, with 2-3 times more damage at the lowest dose rate of 20 krad/h, compared to 4 Mrad/h. The dose rate dependence was also observed to be dependent on transistor size and type.

physics.ins-det↗

arXiv2020

The ABC130 barrel module prototyping programme for the ATLAS strip tracker

For the Phase-II Upgrade of the ATLAS Detector, its Inner Detector, consisting of silicon pixel, silicon strip and transition radiation sub-detectors, will be replaced with an all new 100 % silicon tracker, composed of a pixel tracker at inner radii and a strip tracker at outer radii. The future ATLAS strip tracker will include 11,000 silicon sensor modules in the central region (barrel) and 7,000 modules in the forward region (end-caps), which are foreseen to be constructed over a period of 3.5 years. The construction of each module consists of a series of assembly and quality control steps, which were engineered to be identical for all production sites. In order to develop the tooling and procedures for assembly and testing of these modules, two series of major prototyping programs were conducted: an early program using readout chips designed using a 250 nm fabrication process (ABCN-25) and a subsequent program using a follow-up chip set made using 130 nm processing (ABC130 and HCC130 chips). This second generation of readout chips was used for an extensive prototyping program that produced around 100 barrel-type modules and contributed significantly to the development of the final module layout. This paper gives an overview of the components used in ABC130 barrel modules, their assembly procedure and findings resulting from their tests.

physics.ins-det↗

arXiv2020

New Method for Silicon Sensor Charge Calibration Using Compton Scattering

In order to cope with increasing lifetime radiation damage expected at collider experiments, silicon sensors are becoming increasingly thin. To achieve adequate detection efficiency, the next generation of detectors may have to operate with thresholds below 1000 electron-hole pairs. The readout chips attached to these sensors should be calibrated to some known external charge, but there is a lack of traditional sources in this charge regime. We present a new method for absolute charge calibration based on Compton scattering. In the past, this method has been used for calibration of scintillators, but to our knowledge never for silicon detectors. Here it has been studied using a 150 micron thick planar silicon sensor on an RD53A readout integrated circuit.

physics.ins-det↗

arXiv2019

Measured Effectiveness of Deep N-well Substrate Isolation in a 65nm Pixel Readout Chip Prototype

The same charge sensitive preamplifier and discriminator circuit with different isolation strategies has been tested to compare the isolation of both analog and digital circuits from the substrate of a 65nm bulk CMOS process to the isolation of only digital circuits, tying analog ground locally to the substrate. This study will show that the circuit with analog on the substrate and digital in deep N-well has better noise isolation between analog and digital.

physics.ins-det↗

arXiv2017

Self-Adjusting Threshold Mechanism for Pixel Detectors

Readout chips of hybrid pixel detectors use a low power amplifier and threshold discrimination to process charge deposited in semiconductor sensors. Due to transistor mismatch each pixel circuit needs to be calibrated individually to achieve response uniformity. Traditionally this is addressed by programmable threshold trimming in each pixel, but requires robustness against radiation effects, temperature, and time. In this paper a self-adjusting threshold mechanism is presented, which corrects the threshold for both spatial inequality and time variation and maintains a constant response. It exploits the electrical noise as relative measure for the threshold and automatically adjust the threshold of each pixel to always achieve a uniform frequency of noise hits. A digital implementation of the method in the form of an up/down counter and combinatorial logic filter is presented. The behavior of this circuit has been simulated to evaluate its performance and compare it to traditional calibration results. The simulation results show that this mechanism can perform equally well, but eliminates instability over time and is immune to single event upsets.

physics.ins-det↗