22 research outputs found
BULLKID: Monolithic array of particle absorbers sensed by Kinetic Inductance Detectors
We introduce BULLKID, an innovative phonon detector consisting of an array of
dices acting as particle absorbers sensed by multiplexed Kinetic Inductance
Detectors (KIDs). The dices are carved in a thick crystalline wafer and form a
monolithic structure. The carvings leave a thin common disk intact in the
wafer, acting both as holder for the dices and as substrate for the KID
lithography. The prototype presented consists of an array of 64 dices of
5.4x5.4x5 mm carved in a 3" diameter, 5 mm thick silicon wafer, with a
common disk 0.5 mm thick hosting a 60 nm patterned aluminum layer. The
resulting array is highly segmented but avoids the use of dedicated holding
structures for each unit. Despite the fact that the uniformity of the KID
electrical response across the array needs optimization, the operation of 8
units with similar features shows, on average, a baseline energy resolution of
eV. This makes it a suitable detector for low-energy processes such as
direct interactions of dark matter and coherent elastic neutrino-nucleus
scattering
Observation of a nuclear recoil peak at the 100 eV scale induced by neutron capture
Coherent elastic neutrino-nucleus scattering and low-mass Dark Matter
detectors rely crucially on the understanding of their response to nuclear
recoils. We report the first observation of a nuclear recoil peak at around 112
eV induced by neutron capture. The measurement was performed with a CaWO
cryogenic detector from the NUCLEUS experiment exposed to a Cf source
placed in a compact moderator. The measured spectrum is found in agreement with
simulations and the expected peak structure from the single-
de-excitation of W is identified with 3 significance. This
result demonstrates a new method for precise, in-situ, and non-intrusive
calibration of low-threshold experiments
Low-energy spectrum of the BULLKID detector array operated on surface
International audienceWe present the first continuous operation in a surface lab of BULLKID, a detector for searches of light Dark Matter and precision measurements of the coherent and elastic neutrino-nucleus scattering. The detector consists of an array of 60 cubic silicon particle absorbers of 0.34 g each, sensed by cryogenic kinetic inductance detectors. The data presented focusses on one of the central elements of the array and on its surrounding elements used as veto. The energy spectrum resulting from an exposure of 39 hours to ambient backgrounds, obtained without radiation shields, is flat at the level of counts / keV kg days down to the energy threshold of eV. The data analysis demonstrates the unique capability of rejecting backgrounds generated from interactions in other sites of the array, stemming from the segmented and monolithic structure of the detector
BULLKID: Monolithic array of particle absorbers sensed by Kinetic Inductance Detectors
International audienceWe introduce BULLKID, an innovative phonon detector consisting of an array of dices acting as particle absorbers sensed by multiplexed Kinetic Inductance Detectors (KIDs). The dices are carved in a thick crystalline wafer and form a monolithic structure. The carvings leave a thin common disk intact in the wafer, acting both as holder for the dices and as substrate for the KID lithography. The prototype presented consists of an array of 64 dices of 5.4x5.4x5 mm carved in a 3" diameter, 5 mm thick silicon wafer, with a common disk 0.5 mm thick hosting a 60 nm patterned aluminum layer. The resulting array is highly segmented but avoids the use of dedicated holding structures for each unit. Despite the fact that the uniformity of the KID electrical response across the array needs optimization, the operation of 8 units with similar features shows, on average, a baseline energy resolution of eV. This makes it a suitable detector for low-energy processes such as direct interactions of dark matter and coherent elastic neutrino-nucleus scattering
Study of collision and -cascade times following neutron-capture processes in cryogenic detectors
International audienceThe emission of -rays after a neutron capture in a cryogenic detector can generate mono-energetic nuclear recoils in the sub-keV regime, of direct interest for the calibration of Dark Matter and Coherent Elastic Neutrino Nucleus Scattering experiments. Here we show that accurate predictions of the nuclear recoil spectra induced by neutron captures require taking into account the interplay between the development in time of the de-excitation -cascade of the target nucleus and that of the associated atomic collisions in matter. We present detailed simulations coupling the FIFRELIN code for the description of the -cascades and the IRADINA code for the modelling of the fast atomic movements in matter. Nuclear recoil spectra are predicted, and made available to the community, for concrete cases of AlO, Si, Ge and CaWO crystals exposed to a low intensity beam of thermal neutrons. We find that timing effects cause new calibration peaks to emerge in the recoil spectra and also impact the shape of the continuous recoil distribution. We discuss how they could give access to a rich physics program, spanning the accurate study of the response of cryogenic detectors in the sub-keV range, tests of solid state physics simulations and tests of nuclear models
Study of collision and -cascade times following neutron-capture processes in cryogenic detectors
International audienceThe emission of -rays after a neutron capture in a cryogenic detector can generate mono-energetic nuclear recoils in the sub-keV regime, of direct interest for the calibration of Dark Matter and Coherent Elastic Neutrino Nucleus Scattering experiments. Here we show that accurate predictions of the nuclear recoil spectra induced by neutron captures require taking into account the interplay between the development in time of the de-excitation -cascade of the target nucleus and that of the associated atomic collisions in matter. We present detailed simulations coupling the FIFRELIN code for the description of the -cascades and the IRADINA code for the modelling of the fast atomic movements in matter. Nuclear recoil spectra are predicted, and made available to the community, for concrete cases of AlO, Si, Ge and CaWO crystals exposed to a low intensity beam of thermal neutrons. We find that timing effects cause new calibration peaks to emerge in the recoil spectra and also impact the shape of the continuous recoil distribution. We discuss how they could give access to a rich physics program, spanning the accurate study of the response of cryogenic detectors in the sub-keV range, tests of solid state physics simulations and tests of nuclear models
Exploring coherent elastic neutrino-nucleus scattering of reactor neutrinos with the NUCLEUS experiment
International audienceThe NUCLEUS experiment aims to perform a high-precision measurement of Coherent Elastic Neutrino-Nucleus Scattering (CEvNS) at the EdF Chooz B nuclear power plant in France. CEvNS is a unique process to study neutrino properties and to search for physics beyond the Standard Model. The study of CEvNS is also important for light Dark-Matter searches. It could be a possible irreducible background for high-sensitivity Dark-Matter searches. NUCLEUS is an experiment under construction based on ultra-low threshold (20 eVnr) cryogenic calorimeters, operated at tens-of-mK temperatures
Exploring coherent elastic neutrino-nucleus scattering of reactor neutrinos with the NUCLEUS experiment
International audienceThe NUCLEUS experiment aims to perform a high-precision measurement of Coherent Elastic Neutrino-Nucleus Scattering (CEvNS) at the EdF Chooz B nuclear power plant in France. CEvNS is a unique process to study neutrino properties and to search for physics beyond the Standard Model. The study of CEvNS is also important for light Dark-Matter searches. It could be a possible irreducible background for high-sensitivity Dark-Matter searches. NUCLEUS is an experiment under construction based on ultra-low threshold (20 eVnr) cryogenic calorimeters, operated at tens-of-mK temperatures