arXiv subjects

Ruben Saakyan

Publications and source records attributed to Ruben Saakyan.

5 recordsLinked to original sources

arXiv2026

Commissioning and first results from the Cold Radon Emanation Facility

Radon emanation from detector materials is a critical background for next-generation rare event searches, in particular those using noble liquid targets. While highly sensitive screening facilities mitigate this risk prior to detector construction, room-temperature assays often fail to predict cold emanation rates due to temperature-dependent diffusion suppression. The Cold Radon Emanation Facility at Rutherford Appleton Laboratory addresses this by performing high-sensitivity assays at detector operating temperatures. It includes a 2.7 L small-sample chamber, a 200 L chamber for large as-built components operated with a radon concentration line, a cryogenic infrastructure enabling measurements of emanation as a function of temperature, and an electrostatic radon detector, which achieves a minimum detectable activity of ~0.05 mBq at 90% CL. Commissioning results and initial comparative assays are reported, including a preliminary indication of a factor of ~2 suppression of $^{222}$Rn emanation in a titanium sample at cryogenic temperatures. This result, obtained as part of commissioning measurements, illustrates the potential impact of temperature-dependent effects and underscores the importance of in-situ cold assays for future noble liquid detector components.

physics.ins-det↗

arXiv2025

Enhancing Material Screening at Boulby Underground Laboratory with XIA UltraLo-1800 Alpha Particle Detectors

The Boulby UnderGround Screening (BUGS) facility, located at the Boulby Underground Laboratory, has significantly advanced its material screening capabilities by installing two XIA UltraLo-1800 alpha particle detectors. This study presents a comprehensive evaluation of one of these detectors, operated 1,100 meters underground at the Boulby Underground Laboratory, which provides significant shielding from cosmic radiation and maintains a low ambient radon activity of 2.30 $\pm$ 0.03 Bq/m$^3$. Our evaluation focuses on energy reconstruction accuracy, background radiation rates, and operational stability. The XIA UltraLo-1800 detector demonstrates remarkable stability in energy reconstruction, with less than 0.1 MeV variation over four years. Moreover, the implementation of a graphite-filled PTFE liner in the sample tray resulted in a significant reduction in background radiation levels compared to measurements with the original stainless steel tray, achieving an average activity of 0.15 $\pm$ 0.01 $α$/cm$^2$/khr. Copper sample assays, performed before and after radon exposure, demonstrated the detector's ability to accurately identify and quantify $^{210}$Po contamination. By implementing the robust cleanliness procedures and protocols described in this article, we observed a reduction in $^{210}$Po activity from 0.504 $\pm$ 0.022 mBq to 0.336 $\pm$ 0.013 mBq, highlighting the crucial role of refined cleaning methods in minimizing background for sensitive experiments. Additionally, observations of elevated background activity levels post-high-activity sample measurements illustrate the need for careful management of assay conditions and environment to maintain low background levels. These results highlight the potential of the XIA UltraLo-1800 in enhancing the precision of material assays essential for reducing background interference in rare event experiments.

physics.ins-det↗

arXiv2022

Requirements on Quantum Superpositions of Macro-Objects for Sensing Neutrinos

We examine a macroscopic system in a quantum superposition of two spatially separated localized states as a detector for a stream of weakly interacting relativistic particles. We do this using the explicit example of neutrinos with MeV-scale energy scattering from a solid object via neutral-current neutrino-nucleus scattering. Presuming the (anti-)neutrino source to be a nuclear fission reactor, we utilize the estimated flux and coherent elastic neutrino-nucleus cross section to constrain the spatial separation $Δ$x and describe the temporal evolution of the sensing system. Particularly, we find that a potentially measurable relative phase between quantum superposed components is obtained for a single gram scale mass placed in a superposition of spatial components separated by $10^{-14}$m under sufficient cooling and background suppression.

quant-ph↗

arXiv2021

A High Pressure Time Projection Chamber with Optical Readout

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.

physics.ins-det↗

arXiv2020

Performance of different photocathode materials in a liquid argon purity monitor

Purity monitor devices are increasingly used in noble gas time projection chambers to measure the lifetime of drifting electrons. Purity monitors work by emitting electrons from a photocathode material via the photoelectric effect. The electrons are then drifted towards an anode by means of an applied electric drift field. By measuring the difference in charge between the cathode and the anode, one can extract the lifetime of the drifting electrons in the medium. For the first time, we test the performance of different photocathode materials-- silver, titanium, and aluminium--and compare them to gold, which is the standard photocathode material used for purity monitors. Titanium and aluminium were found to have a worse performance than gold in vacuum, whereas silver showed a signal of the same order of magnitude as gold. Further tests in liquid argon were carried out on silver and gold with the conclusion that the signal produced by silver is about three times stronger than that of gold.

physics.ins-det↗