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Dastgheibi-Fard, A.

Publications and source records attributed to Dastgheibi-Fard, A..

7 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

The DAMIC-M Low Background Chamber

The DArk Matter In CCDs at Modane (DAMIC-M) experiment isdesigned to search for light dark matter (m$_{χ}$ < 10 GeV/c$^{2}$)at the Laboratoire Souterrain de Modane (LSM) in France. DAMIC-Mwill use skipper charge-coupled devices (CCDs) as a kg-scale activedetector target. Its single-electron resolution will enable eV-scaleenergy thresholds and thus world-leading sensitivity to a range ofhidden sector dark matter candidates. A DAMIC-M prototype, the LowBackground Chamber (LBC), has been taking data at LSM since2022. The LBC provides a low-background environment, which has beenused to characterize skipper CCDs, study dark current, and measureradiopurity of materials planned for DAMIC-M. It also allows testingof various subsystems like readout electronics, data acquisitionsoftware, and slow control. This paper describes the technicaldesign and performance of the LBC.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2024

Confirmation of the spectral excess in DAMIC at SNOLAB with skipper CCDs

Here, we present results from a 3.25 kg–day target exposure of two silicon charge-coupled devices (CCDs), each with 24 megapixels and skipper readout, deployed in the DAMIC setup at SNOLAB. With a reduction in pixel readout noise of a factor of 10 relative to the previous detector, we investigate the excess population of low-energy events in the CCD bulk previously observed above expected backgrounds. We address the dominant systematic uncertainty of the previous analysis through a depth fiducialization designed to reject surface backgrounds on the CCDs. The measured bulk ionization spectrum confirms the presence of an excess population of low-energy events in the CCD target with characteristic rate of ~7 events per kg-day and electron-equivalent energies of ~80 eV, whose origin remains unknown.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2023

The DAMIC-M experiment: Status and first results

The DAMIC-M (DArk Matter In CCDs at Modane) experiment employs thick, fully depleted silicon charged-coupled devices (CCDs) to search for dark matter particles with a target exposure of 1 kg-year. A novel skipper readout implemented in the CCDs provides single electron resolution through multiple non-destructive measurements of the individual pixel charge, pushing the detection threshold to the eV-scale. DAMIC-M will advance by several orders of magnitude the exploration of the dark matter particle hypothesis, in particular of candidates pertaining to the so-called “hidden sector.” A prototype, the Low Background Chamber (LBC), with 20g of low background Skipper CCDs, has been recently installed at Laboratoire Souterrain de Modane and is currently taking data. We will report the status of the DAMIC-M experiment and first results obtained with LBC commissioning data.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2023

The NEWS-G detector at SNOLAB

The New Experiments With Spheres-Gas (NEWS-G) collaboration intends to achieve sub-GeV/c 2 Weakly Interacting Massive Particles (WIMPs) detection using Spherical Proportional Counters (SPCs). SPCs are gaseous detectors relying on ionisation with a single ionization electron energy threshold. The latest generation of SPC for direct dark matter searches has been installed at SNOLAB in Canada in 2021. This article details the different processes involved in the fabrication of the NEWS-G experiment. Also outlined in this paper are the mitigation strategies, measurements of radioactivity of the different components, and estimations of induced background event rates that were used to quantify and address detector backgrounds.

47 OTHER INSTRUMENTATION↗
DOE OSTI2022

Measurements of the ionization efficiency of protons in methane

The amount of energy released by a nuclear recoil ionizing the atoms of the active volume of detection appears “quenched” compared to an electron of the same kinetic energy. This different behavior in ionization between electrons and nuclei is described by the Ionization Quenching Factor (IQF) and it plays a crucial role in direct dark matter searches. For low kinetic energies (below 50 keV ), IQF measurements deviate significantly from common models used for theoretical predictions and simulations. We report measurements of the IQF for proton, an appropriate target for searches of Dark Matter candidates with a mass of approximately 1 GeV , with kinetic energies in between 2 keV and 13 keV in 100 mbar of methane. We used the Comimac facility in order to produce the motion of nuclei and electrons of controlled kinetic energy in the active volume, and a NEWS-G SPC to measure the deposited energy. The Comimac electrons are used as a reference to calibrate the detector with 7 energy points. A detailed study of systematic effects led to the final results well fitted by IQF (E K )=E$^α_K$ / (β+E$^α_K$) with α=0.70±0.08 and β=1.32±0.17 . In agreement with some previous works in other gas mixtures, we measured less ionization energy than predicted from SRIM simulations, the difference reaching 33% at 2 keV .

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2022

EXCESS workshop: Descriptions of rising low-energy spectra

Many low-threshold experiments observe sharply rising event rates of yet unknown origins below a few hundred eV, and larger than expected from known backgrounds. Due to the significant impact of this excess on the dark matter or neutrino sensitivity of these experiments, a collective effort has been started to share the knowledge about the individual observations. For this, the EXCESS Workshop was initiated. In its first iteration in June 2021, ten rare event search collaborations contributed to this initiative via talks and discussions. The contributing collaborations were CONNIE, CRESST, DAMIC, EDELWEISS, MINER, NEWS-G, NUCLEUS, RICOCHET, SENSEI and SuperCDMS. They presented data about their observed energy spectra and known backgrounds together with details about the respective measurements. In this paper, we summarize the presented information and give a comprehensive overview of the similarities and differences between the distinct measurements. The provided data is furthermore publicly available on the workshop's data repository together with a plotting tool for visualization.

Adari, Prakruth↗