arXiv subjects

D. Münstermann

Publications and source records attributed to D. Münstermann.

6 recordsLinked to original sources

arXiv2026

Characterisation of silicon photomultipliers in a dilution refrigerator down to 9.4 mK towards a cryogenic cosmic-ray muon veto system

We report the characterisation of a FBK NUV-HD-cryo silicon photomultiplier (SiPM) sensor operated in a 9.4 $\pm$ 0.2 mK environment inside a dilution refrigerator, towards the development of a cryogenic cosmic ray muon veto system to be operated internal to a dilution refrigerator required for low background experiments such as the QUEST-DMC dark matter search experiment. We characterise the single photon response and the gain (the charge produced per detected photon), the dark count noise rate, and correlated noise contributions as a function of operating voltage. This paper also reports first proof-of-concept measurements of using a SiPM coupled to scintillator internal to a dilution refrigerator, towards detecting high-energy events consistent with candidate cosmic-ray muon signals.

physics.ins-det↗

arXiv2025

Development of superfluid helium-3 bolometry using nanowire resonators with SQUID readout for the QUEST-DMC experiment

Superfluid helium-3 bolometers can be utilised for dark matter direct detection searches. The extremely low heat capacity of the B phase of the superfluid helium-3 at ultra-low temperatures offers the potential to reach world leading sensitivity to spin dependent interactions of dark matter in the sub-GeV/c$^2$ mass range. Here, we describe the development of bolometry using both micron scale and sub-micron diameter vibrating wire resonators, with a SQUID amplifier-based readout scheme. Characterisation of the resonators and bolometer measurements are shown, including the use of non-linear operation and the corresponding corrections. The bolometer contains two vibrating wire resonators, enabling heat injection calibration and simultaneous bolometer tracking measurements. Coincident events measured on both vibrating wire resonators verify their response. We also demonstrate proof of concept frequency multiplexed readout. Development of these measurement techniques lays the foundations for the use of superfluid helium-3 bolometers, instrumented with vibrating nano-mechanical resonators, for future low threshold dark matter searches.

physics.ins-det↗

arXiv2012

Planar Pixel Sensors for the ATLAS Upgrade: Beam Tests results

Results of beam tests with planar silicon pixel sensors aimed towards the ATLAS Insertable B-Layer and High Luminosity LHC (HL-LHC) upgrades are presented. Measurements include spatial resolution, charge collection performance and charge sharing between neighbouring cells as a function of track incidence angle for different bulk materials. Measurements of n-in-n pixel sensors are presented as a function of fluence for different irradiations. Furthermore p-type silicon sensors from several vendors with slightly differing layouts were tested. All tested sensors were connected by bump-bonding to the ATLAS Pixel read-out chip. We show that both n-type and p-type tested planar sensors are able to collect significant charge even after integrated fluences expected at HL-LHC.

physics.ins-det↗

arXiv2009

An Investigation into the 113-Cd Beta Decay Spectrum using a CdZnTe Array

We present 11 independent measurements of the half-life and spectral shape of the 4-fold forbidden beta decay of 113-Cd using CdZnTe semiconductors with a total combined lifetime of 6.58 kg days. Our overall result gives a half-life of (8.00 +/- 0.11(stat) +/- 0.24(sys)) x 10^15 years and a Q value of 322.2 +/- 0.3(stat) +/- 0.9(sys) keV. For the first time half-lives well beyond 10^10 years have been deduced with a statistically representative sample of independent measurements.

nucl-ex↗

arXiv2007

First results on double beta decay modes of Cd, Te and Zn isotopes with the COBRA experiment

Four 1cm^3 CdZnTe semiconductor detectors were operated in the Gran Sasso National Laboratory to explore the feasibility of such devices for double beta decay searches as proposed for the COBRA experiment. The research involved background studies accompanied by measurements of energy resolution performed at the surface. Energy resolutions sufficient to reduce the contribution of two-neutrino double beta decay events to a negligible level for a large scale experiment have already been achieved and further improvements are expected. Using activity measurements of contaminants in all construction materials a background model was developed with the help of Monte Carlo simulations and major background sources were identified. A total exposure of 4.34 kg.days of underground data has been accumulated allowing a search for neutrinoless double beta decay modes of seven isotopes found in CdZnTe. Half-life limits (90% C.L.) are presented for decays to ground and excited states. Four improved lower limits have been obtained, including zero neutrino double electron capture transitions of Zn64 and Te120 to the ground state, which are 1.19*10^{17} years and 2.68*10^{15} years respectively.

nucl-ex↗

arXiv2003

A Search for various Double Beta Decay Modes of Cd, Te and Zn Isotopes

Various double beta decay modes of Cd, Zn and Te isotopes are explored with the help of CdTe and CdZnTe semiconductor detectors. The data set is splitted in an energy range below 1 MeV having a statistics of 134.5 g$\cdot$d and one above 1 MeV resulting in 532 g$\cdot$d. No signals were observed in all channels under investigation. New improved limits for the neutrinoless double beta decay of Zn70 of $T_{1/2} > 1.3 \cdot 10^{16} yrs$ (90% CL), the longest standing limit of all double beta isotopes, and 0$νβ^+$EC of Te120 of $T_{1/2} > 2.2 \cdot 10^{16} yrs$ (90% CL) are given. For the first time a limit on the half-life of the 2$ν$ECEC of $^{120}$Te of $T_{1/2} > 9.4 \cdot 10^{15} yrs$ (90% CL) is obtained. In addition, limits on 2$ν$ECEC for ground state transitions of Cd106, Cd108 and Zn64 are improved. The obtained results even under rough background conditions show the reliability of CdTe semiconductor detectors for rare nuclear decay searches.

nucl-ex↗