Physics

I describe a possible Forward Multiparticle Spectrometer (FMS) that could be installed downstream of the superconducting recombination dipole D1 in Run 4, from z = 96 m - 126 m to measure multi-TeV hadron spectra in low luminosity p + p collisions at Rt(s) = 14 TeV, as well as p + O and O + O collisions as relevant for cosmic ray showers. Light antinuclei and charmed hadrons at high Feynman xF can be measured, both of importance for astrophysics. At the full high luminosity HL-LHC a search for new long-lived neutral particles (LLPs) decaying in a 20 m long, 70 cm diameter vacuum pipe to visible decay modes (including gamma+gamma, e+e-, mu+mu-, tau+tau-, ccbar and jets) can be made. The FMS is especially well suited for LLPs with 1 GeV < M(X)< 10 GeV and lifetimes c.tau from about 10 m to several km. I discuss this as a possible addition to CMS but it has no formal approval yet, therefore the talk is not given on behalf of CMS.

In recent years Gas Electron Multipliers have proven to be reliable amplification stages at high beam rates, and can be used also in Time Projection Chambers. Our group developed a 1 dm 3 active volume double-GEM TPC, with spatial resolution of 50 μm and 280 μ m. Custom designed FPGA data acquisition system enables rate capability for about 100 kHz ⋅ mm −2 , providing excellent track-by-track position and angular information, better than 0.1 mm and 1 mrad respectively. The wide dynamic range of the system enables identification from 4 He up to 86 Kr using ionization measurement. Two of these TPCs are planned to operate in tandem mode to filter off-time particles and to achieve a superior angular resolution.

Time Projection Chambers (TPCs) operated at high pressure have become a topic of interest for future long baseline neutrino experiments. Pressurized gas retains the low momentum threshold for particle detection of atmospheric TPCs, but offers a larger target mass for neutrino interactions at the same volume. Operation at high pressure poses several new challenges in safety aspects regarding overpressure and high voltage safety. The presented High Pressure Gas Monitoring Chamber (HPGMC) can be used to study the suitability of various drift gas mixtures up to 10 bar and a maximum field of ∼ 3000 V/cm . A flexible construction makes it possible to exchange parts of the inner detector and to test new technologies. In this work, the construction of a HPGMC and its commissioning using the P10 gas mixture ( 90%Ar+10% CH 4 ) are presented.

Measurements of proton-nucleus scattering and high resolution neutrino-nucleus interaction imaging are key to reduce neutrino oscillation systematic uncertainties in future experiments. A High Pressure Time Projection Chamber (HPTPC) prototype has been constructed and operated at Royal Holloway University of London and CERN as a first step in the development of a HPTPC capable of performing these measurements as part of a future long-baseline neutrino oscillation experiment such as the Deep Underground Neutrino Experiment. In this paper we describe the design and operation of the prototype HPTPC with an argon based gas mixture. We report on the successful hybrid charge and optical readout, using four CCD cameras, of signals from Am-241 sources.

Scintillation from noble gases is an important technique in particle physics including neutrino beam experiments, neutrino-less double beta-decay and dark matter searches. In liquid argon, the possibility of enhancing the light yield by the addition of a small quantity of xenon (doping at 10-1000 ppm) has been of particular interest. While the pathway for energy transfer between argon and xenon excimers is well known, the time-dependence of the process has not been fully studied in the context of a physics-based model. In this paper we present a model of the energy transfer process together with a fit to xenon-doped argon data. We have measured the diffusion limited rate constant as a function of xenon dopant. We find that the time dependence of the energy transfer is consistent with diffusion-limited reactions. Additionally, we find that commercially obtained argon can have a small xenon component (4 ppm). Our result will facilitate the use of xenon-doped liquid argon in future experiments.

We describe a torsion pendulum with a large mass-quadrupole moment and a resonant frequency of 2.8 mHz, whose angle is measured using a modified Michelson interferometer. The system achieved noise levels of ??00 prad/ Hz ????????between 0.2-30 Hz and ??0 prad/ Hz ????????above 100 Hz. Such a system can be applied to a broad range of fields from the study of rotational seismic motion and elastogravity signals to gravitational wave observation and tests of gravity.

In this paper, we present a dual-channel serializer ASIC, LOCx2, and its pin-compatible backup, LOCx2-130, for detector front-end readout. LOCx2 is fabricated in a 0.25-um Silicon-on-Sapphire CMOS process and each channel operates at 5.12 Gbps, while LOCx2-130 is fabricated in a 130-nm bulk CMOS process and each channel operates at 4.8 Gbps. The power consumption and the transmission latency are 900 mW and 27 ns for LOCx2 and the corresponding simulation result of LOCx2-130 are 386 mW and 38 ns, respectively.

This paper presents a millimeter-scale CMOS 64 × 64 single charged particle radiation detector system for external beam cancer radiotherapy. A 1 × 1 μ m 2 diode measures energy deposition by a single charged particle in the depletion region, and the array design provides a large detection area of 512 × 512 μ m 2 . Instead of sensing the voltage drop caused by radiation, the proposed system measures the pulse width, i.e., the time it takes for the voltage to return to its baseline. This obviates the need for using power-hungry and large analog-to-digital converters. A prototype ASIC is fabricated in TSMC 65 nm LP CMOS process and consumes the average static power of 0.535 mW under 1.2 V analog and digital power supply. The functionality of the whole system is successfully verified in a clinical 67.5 MeV proton beam setting. To our' knowledge, this is the first work to demonstrate single charged particle detection for implantable in-vivo dosimetry.

In a comprehensive study on several samples we demonstrate for our laboratory-based computed tomography system resolutions down to 150nm. The achieved resolution is validated by imaging com-mon test structures in 2D and Fourier Shell Correlation of 3D volumes. As representative application examples from nowadays material research, we show metallization processes in multilayer integrated circuits, ageing in lithium battery electrodes, and volumetric of metallic sub-micrometer fillers of com-posites. Thus, our laboratory system provides the unique possibility to image non-destructively struc-tures in the range of hundred nanometers, even for high density materials.

The material eroded from the surface of plasma facing components is redeposited partly close to high heat flux areas. At these locations, the deposit is heated by the plasma and the deposition pattern evolves depending on the operation parameters. The mapping of the deposit is still a matter of intense scientific activity, especially during the course of experimental campaigns. A method based on the comparison of surface temperature maps, obtained in situ by infrared cameras and by theoretical modelling is proposed. The difference between the two is attributed to the thermal resistance added by deposited material, and expressed as a deposit thickness. The method benefits of elaborated imaging techniques such as possibility theory and fuzzy logics. The results are consistent with deposit maps obtained by visual inspection during shutdowns.