A superconducting Transition-Edge Sensor (TES) with low-$T_c$ is essential in
a high resolution calorimetric detection. With a motivation of developing
sensitive calorimeters for applications in ...cryogenic neutrinoless double beta
decay searches, we have been investigating methods to reduce the $T_c$ of an Ir
film down to 20 mK. Utilizing the proximity effect between a superconductor and
a normal metal, we found two room temperature fabrication recipes of making
Ir-based low-$T_c$ films. In the first approach, an Ir film sandwiched between
two Au films, a Au/Ir/Au trilayer, has a tunable $T_c$ in the range of 20-100
mK depending on the relative thicknesses. In the second approach, a
paramagnetic Pt thin film is used to create Ir/Pt bilayer with a tunable $T_c$
in the same range. We present detailed study of fabrication and
characterization of Ir-based low-$T_c$ films, and compare the experimental
results to theoretical models. We show that Ir-based films with predictable and
reproducible critical temperature can be consistently fabricated for use in
large scale detector applications.
The MAJORANA DEMONSTRATOR comprises two arrays of high-purity germanium detectors constructed to search for neutrinoless double-beta decay in 76-Ge and other physics beyond the Standard Model. Its ...readout electronics were designed to have low electronic noise, and radioactive backgrounds were minimized by using low-mass components and low-radioactivity materials near the detectors. This paper provides a description of all components of the MAJORANA DEMONSTRATOR readout electronics, spanning the front-end electronics and internal cabling, back-end electronics, digitizer, and power supplies, along with the grounding scheme. The spectroscopic performance achieved with these readout electronics is also demonstrated.
JINST 13 (2018) P01010 CUORE - the Cryogenic Underground Observatory for Rare Events - is an
experiment searching for the neutrinoless double-beta ($0\nu\beta\beta$) decay
of $^{130}$Te with an array ...of 988 TeO$_2$ crystals operated as bolometers at
$\sim$10 mK in a large dilution refrigerator. With this detector, we aim for a
$^{130}$Te $0\nu\beta\beta$ decay half-life sensitivity of $9\times10^{25}$ y
with 5 y of live time, and a background index of $\lesssim 10^{-2}$
counts/keV/kg/y. Making an effort to maintain radiopurity by minimizing the
bolometers' exposure to radon gas during their installation in the cryostat, we
perform all operations inside a dedicated cleanroom environment with a
controlled radon-reduced atmosphere. In this paper, we discuss the design and
performance of the CUORE Radon Abatement System and cleanroom, as well as a
system to monitor the radon level in real time.
Imperfections in analog-to-digital conversion (ADC) cannot be ignored when signal digitization requirements demand both wide dynamic range and high resolution, as is the case for the Majorana ...Demonstrator 76Ge neutrinoless double beta decay search. Enabling the experiment's high-resolution spectral analysis and efficient pulse shape discrimination required careful measurement and correction of ADC nonlinearites. A simple measurement protocol was developed that did not require sophisticated equipment or lengthy data taking campaigns. A slope-dependent hysteresis was observed and characterized. A correction applied to digitized waveforms prior to signal processing reduced the differential and integral nonlinearites by an order of magnitude, eliminating these as dominant contributions to the systematic energy uncertainty at the double-beta decay Q value.
The prevalence and clinical presentation of schizophrenia and schizophrenia spectrum disorders in general hospitals were studied. The disease incidence rate was estimated at 3.1% that was 3 times ...higher than that in general population. Slow-progredient (latent) schizophrenia with comorbid functional visceral disorders ("organoneurotic" schizophrenia) occurs most frequently. Once manifested, the latter was associated with somatoform disorders during the disease course and developed concomitantly with neurotic and overvalued hypochondria symptoms. The authors suggest that several variants of complex relations between the endogeneous disease (schizophrenia) severity and functional somatic disorders. Slow-progredient (latent) disease reveals an affinity to a number of somatic disorders associated with neurotic and overvalued hypochondria. In more severe disease forms combination of endogenous process with somatoform disorders is accompanied by development of hypochondria with stable algias. In progressive (paranoid) schizophrenia, association with somatoform disorders occurs only at the initial stage of the process. Somatic sensations trigger formation of delusion symptom complexes of cathestesic delusion type.
The Majorana Demonstrator is a neutrinoless double-beta decay search consisting of a low-background modular array of high-purity germanium detectors, \(\sim2/3\) of which are enriched to 88\% in ...\(^{76}\)Ge. The experiment is also searching for double-beta decay of \(^{76}\)Ge to excited states (e.s.) in \(^{76}\)Se. \(^{76}\)Ge can decay into three daughter states of \(^{76}\)Se, with clear event signatures consisting of a \(\beta\beta\)-decay followed by the prompt emission of one or two \(\gamma\)-rays. This results with high probability in multi-detector coincidences. The granularity of the Demonstrator detector array enables powerful discrimination of this event signature from backgrounds. Using 41.9~kg-y of isotopic exposure, the Demonstrator has set world leading limits for each e.s.\ decay of \(^{76}\)Ge, with 90\% CL lower half-life limits in the range of \((0.75-4.0)\times10^{24}\)~y. In particular, for the \(2\nu\) transition to the first \(0^+\) e.s.\ of \(^{76}\)Se, a lower half-life limit of \(7.5\times10^{23}\)~y at 90\% CL was achieved.
J-aggregates and monomers of a thiacarbocyanine derivative are investigated in glassy matrices by spectral hole burning. The temperature dependence (at
T = 4.6−20 K) of the width of the hole burnt in ...the absorption band of aggregates differs qualitatively from that of the hole in the absorption band of monomers. The hole width for
J-aggregates does not depend on temperature below 9 K and is equal to 3.3 cm
−1. This residual hole width is suggested to be determined by exciton-phonon scattering with phonon emission.
A scintillating bolometer based on a large cubic Li$_{2}$$^{100}$MoO$_4$
crystal (45 mm side) and a Ge wafer (scintillation detector) has been operated
in the CROSS cryogenic facility at the Canfranc ...underground laboratory in
Spain. The dual-readout detector is a prototype of the technology that will be
used in the next-generation $0\nu2\beta$ experiment CUPID. The measurements
were performed at 18 and 12 mK temperature in a pulse tube dilution
refrigerator. This setup utilizes the same technology as the CUORE cryostat
that will host CUPID and so represents an accurate estimation of the expected
performance. The Li$_{2}$$^{100}$MoO$_4$ bolometer shows a high energy
resolution of 6 keV FWHM at the 2615 keV $\gamma$ line. The detection of
scintillation light for each event triggered by the Li$_{2}$$^{100}$MoO$_4$
bolometer allowed for a full separation ($\sim$8$\sigma$) between
$\gamma$($\beta$) and $\alpha$ events above 2 MeV. The Li$_{2}$$^{100}$MoO$_4$
crystal also shows a high internal radiopurity with $^{228}$Th and $^{226}$Ra
activities of less than 3 and 8 $\mu$Bq/kg, respectively. Taking also into
account the advantage of a more compact and massive detector array, which can
be made of cubic-shaped crystals (compared to the cylindrical ones), this test
demonstrates the great potential of cubic Li$_{2}$$^{100}$MoO$_4$ scintillating
bolometers for high-sensitivity searches for the $^{100}$Mo $0\nu2\beta$ decay
in CROSS and CUPID projects.
The CUPID Collaboration is designing a tonne-scale, background-free detector
to search for double beta decay with sufficient sensitivity to fully explore
the parameter space corresponding to the ...inverted neutrino mass hierarchy
scenario. One of the CUPID demonstrators, CUPID-Mo, has proved the potential of
enriched Li$_{2}$$^{100}$MoO$_4$ crystals as suitable detectors for
neutrinoless double beta decay search. In this work, we characterised cubic
crystals that, compared to the cylindrical crystals used by CUPID-Mo, are more
appealing for the construction of tightly packed arrays. We measured an average
energy resolution of (6.7$\pm$0.6) keV FWHM in the region of interest,
approaching the CUPID target of 5 keV FWHM. We assessed the identification of
$\alpha$ particles with and without a reflecting foil that enhances the
scintillation light collection efficiency, proving that the baseline design of
CUPID already ensures a complete suppression of this $\alpha$-induced
background contribution. We also used the collected data to validate a Monte
Carlo simulation modelling the light collection efficiency, which will enable
further optimisations of the detector.
P-type point contact (PPC) HPGe detectors are a leading technology for rare
event searches due to their excellent energy resolution, low thresholds, and
multi-site event rejection capabilities. We ...have characterized a PPC detector's
response to $\alpha$ particles incident on the sensitive passivated and p+
surfaces, a previously poorly-understood source of background. The detector
studied is identical to those in the MAJORANA DEMONSTRATOR experiment, a search
for neutrinoless double-beta decay ($0\nu\beta\beta$) in $^{76}$Ge. $\alpha$
decays on most of the passivated surface exhibit significant energy loss due to
charge trapping, with waveforms exhibiting a delayed charge recovery (DCR)
signature caused by the slow collection of a fraction of the trapped charge.
The DCR is found to be complementary to existing methods of $\alpha$
identification, reliably identifying $\alpha$ background events on the
passivated surface of the detector. We demonstrate effective rejection of all
surface $\alpha$ events (to within statistical uncertainty) with a loss of only
0.2% of bulk events by combining the DCR discriminator with previously-used
methods. The DCR discriminator has been used to reduce the background rate in
the $0\nu\beta\beta$ region of interest window by an order of magnitude in the
MAJORANA DEMONSTRATOR, and will be used in the upcoming LEGEND-200 experiment.
