arXiv subjects

C. Toukmenidis

Publications and source records attributed to C. Toukmenidis.

3 recordsLinked to original sources

arXiv2026

Response of a nitrogen-filled spherical proportional counter to mono-energetic neutrons

Neutron spectroscopy is an invaluable tool for a wide range of scientific and industrial applications, however, current approaches suffer from limitations that restrict their field of applicability. A safe and inexpensive alternative approach to neutron detection and spectroscopy is the use of a nitrogen-filled spherical proportional counter that exploits the $^{14}\rm{N(n,p)}^{14}\rm{C}$ and $^{14}\rm{N(n},\alpha)^{11}\rm{B}$ reactions. The neutron spectroscopy capabilities of the detector are demonstrated using beams of mono-energetic neutrons. A nitrogen-filled spherical proportional counter, operating at a pressure of $1$ bar, is exposed to neutrons with energies from $0.75$ MeV to $2.75$ MeV at the Tandem accelerator of the National Centre for Scientific Research ``Demokritos'' in Athens. A linear energy response is observed, within the statistical precision of the measurements.

hep-ex↗

arXiv2026

Radiation Hardness of Commercially Available NUV-MT Silicon Photomultipliers

Silicon Photomultipliers (SiPMs) based on the near-ultraviolet, metal-filled trench (NUV-MT) technology offer improved photon detection efficiency and reduced correlated noise relative to earlier designs, making them attractive for a broad range of particle- and astroparticle-physics applications. As such devices may be deployed in high-radiation environments, quantifying their performance after irradiation is essential. Commercially available Broadcom AFBR-S4N series NUV-MT SiPMs were irradiated with 1 MeV neutrons to fluences between 2x10^{9} and 1.1x10^{10} n_{eq}/cm^2 at the TANDEM accelerator facility of NCSR "Demokritos" in Athens, and characterised before and after irradiation and over successive thermal-annealing stages. Irradiation increased the dark noise by up to three orders of magnitude and degraded the single-photon resolution by up to a factor of ten, with resolution lost entirely at the highest fluence, while no shift in breakdown voltage was observed. Thermal annealing partially recovered the performance, reducing the dark noise by up to a factor of two and restoring the single-photon resolution.

physics.ins-det↗

arXiv2026

Characterisation of Commercially Available NUV-MT Silicon Photomultipliers

Silicon Photomultipliers (SiPMs) based on NUV-MT technology offer improved photo-detection efficiency and reduced correlated noise compared to earlier designs, making them increasingly attractive for particle and astroparticle physics applications. We present a systematic characterisation of commercially available Broadcom AFBR-S4N series NUV-MT SiPMs over a wide range of temperatures and overvoltages, from -85oC to 23oC and from 10-16V overvoltage (VoV). Key performance parameters are measured, including breakdown voltage, gain, signal-to-noise ratio, dark count rate, afterpulsing probability, and both internal and external optical crosstalk. At 12Vov and 23oC a dark noise of 107.2+/-2.1 kcps/mm^2 is measured, consistent with manufacturer specifications. At 12Vov and -30oC the measurements yielded an average dark noise of 1.69+/-0.12 kcps/mm^2, an average gain of (6.88+/-0.15)x10^6, an average signal to noise ratio of 13.6+/-0.9, an average afterpulsing probability of (0.59+/-0.06)%, an average direct crosstalk probability of (26.49+/-0.28)%, an average delayed crosstalk probability of (0.72+/-0.10)%, and an average external crosstalk probability of (0.10+/-0.04)%.

physics.ins-det↗