Search

We tune the onset of optical response in aluminium kinetic inductance detectors from a natural cutoff frequency of 90 GHz to 60 GHz by applying an external magnetic field. The change in spectral response is due to the decrease of the superconducting gap, from 90 GHz at zero magnetic field to 60 GHz at a magnetic field of around 3 mT. We characterize the variation of the superconducting gap, the detector frequency shift and the internal quality factor as a function of the applied field. In principle, the magnetic field tunable response could be used to make spectroscopic measurements. In practice, the internal quality factor behaves hysteretically with the magnetic field due to the presence of vortices in the thin superconducting film. We conclude by discussing possible solutions to achieve spectroscopy measurements using kinetic inductance detectors and magnetic field.

We present the data-processing algorithms and the performance of CONCERTO (CarbON CII line in post-rEionisation and ReionisaTiOn epoch) in continuum by analysing the data from the commissioning and scientific observations. The beam pattern is characterized by an effective FWHM of 31.9 $\pm$ 0.6" and 34.4 $\pm$ 1.0" for high-frequency (HF) and low-frequency (LF) bands. The main beam is slightly elongated with a mean eccentricity of 0.46. Two error beams of $\sim$65" and $\sim$130" are characterized, enabling the estimate of a main beam efficiency of $\sim$0.52. The field of view is accurately reconstructed and presents coherent distortions between the HF and LF arrays. LEKID parameters were robustly determined for 80% of the read tones. Cross-talks between LEKIDs are the first cause of flagging, followed by an excess of eccentricity for $\sim$10% of the LEKIDs, all located in a given region of the field of view. On the 44 scans of Uranus selected for the absolute photometric calibration, 72.5% and 78.2% of the LEKIDs are selected as valid detectors with a probability >70%. By comparing Uranus measurements with a model, we obtain calibration factors of 19.5$\pm$0.6 [Hz/Jy] and 25.6$\pm$0.9 [Hz/Jy] for HF and LF. The point-source continuum measurement uncertainties are 3.0% and 3.4% for HF and LF bands. The RMS of CONCERTO maps is verified to evolve as proportional to the inverse square root of integration time. The measured NEFDs for HF and LF are 115$\pm$2 mJy/beam$\cdot$s$^{1/2}$ and 95$\pm$1 mJy/beam$\cdot$s$^{1/2}$, obtained using CONCERTO data on the COSMOS field for a mean precipitable water vapour and elevation of 0.81 mm and 55.7 deg. CONCERTO demonstrates unique capabilities in fast dual-band spectral mapping with a $\sim$18.5' instantaneous field-of-view. CONCERTO's performance in continuum is perfectly in line with expectations., Comment: 23pages, 22 figures

The Biot problem of poroelasticity is extended by Signorini contact conditions. The resulting Biot contact problem is formulated and analyzed as a two field variational inequality problem of a perturbed saddle point structure. We present an a priori error analysis for a general as well as for a $hp$-FE discretization including convergence and guaranteed convergence rates for the latter. Moreover, we derive a family of reliable and efficient residual based a posteriori error estimators, and elaborate how a simple and efficient primal-dual active set solver can be applied to solve the discrete Galerkin problem. Numerical results underline our theoretical finding and show that optimal, in particular exponential, convergence rates can be achieved by adaptive schemes for two dimensional problems.

Besides its fundamental interest, understanding the dynamics of pair breaking in superconducting nanostructures is a central issue to optimize the performances of superconducting devices such as qubits or photon detectors. However, despite substantial research efforts, these dynamics are still not well understood as this requires experiments in which quasiparticles are injected in a controlled fashion. Until now, such experiments have employed solid-state tunnel junctions with a fixed tunnel barrier. Here we use instead a cryogenic scanning tunnelling microscope to tune independently the energy and the rate of quasiparticle injection through, respectively, the bias voltage and the tunnelling current. For high energy quasiparticles, we observe the reduction of the critical current of a nanowire and show it is mainly controlled by the injected power and, marginally, by the injection rate. Our results prove a thermal mechanism for the reduction of the critical current and unveil the rapid dynamics of the generated hot spot., Comment: 25 pages, 14 figures

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., Comment: For submission to JINST, 17 figures. v2: revised version

CONCERTO (CarbON CII line in post-rEionisation and ReionisaTiOn) is a large field-of-view (FoV) spectro-imager that has been installed on the Cassegrain Cabin of Atacama Pathfinder EXperiment (APEX) telescope in April 2021. CONCERTO hosts 2 focal planes and a total number of 4000 Kinetic Inductance Detectors (KID), with an instantaneous FoV of 18.6 arcminutes in the range of 130-310 GHz. The spectral resolution can be easily tuned down to 1 GHz depending on the scientific target. The scientific program of CONCERTO has many objectives, with two main programs focused on mapping the fluctuations of the [CII] line intensity in the reionisation and post-reionisation epoch (4.5

Experiments searching for very rare processes such as neutrinoless double-beta decay require a detailed understanding of all sources of background. Signals from radioactive impurities present in construction and detector materials can be suppressed using a number of well-understood techniques. Background from in-situ cosmogenic interactions can be reduced by siting an experiment deep underground. However, the next generation of such experiments have unprecedented sensitivity goals of 10$^{28}$ years half-life with background rates of 10$^{-5}$cts/(keV kg yr) in the region of interest. To achieve these goals, the remaining cosmogenic background must be well understood. In the work presented here, Majorana Demonstrator data is used to search for decay signatures of meta-stable germanium isotopes. Contributions to the region of interest in energy and time are estimated using simulations, and compared to Demonstrator data. Correlated time-delayed signals are used to identify decay signatures of isotopes produced in the germanium detectors. A good agreement between expected and measured rate is found and different simulation frameworks are used to estimate the uncertainties of the predictions. The simulation campaign is then extended to characterize the background for the LEGEND experiment, a proposed tonne-scale effort searching for neutrinoless double-beta decay in $^{76}$Ge., Comment: 14 pages, 12 figures

We describe the deployment and first tests on Sky of CONCERTO, a large field-of-view (18.6arc-min) spectral-imaging instrument. The instrument operates in the range 130-310GHz from the APEX 12-meters telescope located at 5100m a.s.l. on the Chajnantor plateau. Spectra with R=1-300 are obtained using a fast (2.5Hz mechanical frequency) Fourier Transform Spectrometer (FTS), coupled to a continuous dilution cryostat with a base temperature of 60mK. Two 2152-pixels arrays of Lumped Element Kinetic Inductance Detectors (LEKID) are installed in the cryostat that also contains the cold optics and the front-end electronics. CONCERTO, installed in April 2021, generates more than 20k spectra per second during observations. We describe the final development phases, the installation and the first results obtained on Sky., Comment: Submitted to JLTP, Proceedings if the Low Temperature Detectors 19 conference, NIST, 2021

A posteriori error estimates are constructed for the three-field variational formulation of the Biot problem involving the displacements, the total pressure and the fluid pressure. The discretization under focus is the H1({\Omega})-conforming Taylor-Hood finite element combination, consisting of polynomial degrees k + 1 for the displacements and the fluid pressure and k for the total pressure. An a posteriori error estimator is derived on the basis of H(div)-conforming reconstructions of the stress and flux approximations. The symmetry of the reconstructed stress is allowed to be satisfied only weakly. The reconstructions can be performed locally on a set of vertex patches and lead to a guaranteed upper bound for the error with a constant that depends only on local constants associated with the patches and thus on the shape regularity of the triangulation. Particular emphasis is given to nearly incompressible materials and the error estimates hold uniformly in the incompressible limit. Numerical results on the L-shaped domain confirm the theory and the suitable use of the error estimator in adaptive strategies.

We have fabricated an array of subgap kinetic inductance detectors (SKIDs) made of granular aluminum ($T_c\sim$2~K) sensitive in the 80-90 GHz frequency band and operating at 300~mK. We measure a noise equivalent power of $1.3\times10^{-16}$~W/Hz$^{0.5}$ on average and $2.6\times10^{-17}$~W/Hz$^{0.5}$ at best, for an illuminating power of 50~fW per pixel. Even though the circuit design of SKIDs is identical to that of the kinetic inductance detectors (KIDs), the SKIDs operating principle is based on their sensitivity to subgap excitations. This detection scheme is advantageous because it avoids having to lower the operating temperature proportionally to the lowest detectable frequency. The SKIDs presented here are intrinsically selecting the 80-90 GHz frequency band, well below the superconducting spectral gap of the film, at approximately 180 GHz., Comment: Suggestions and comments are welcome

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., Comment: 16 pages, 11 figures

Characterise the large-scale structure in the Universe from present times to the high redshift epoch of reionisation is essential to constraining the cosmology, the history of star formation and reionisation, measuring the gas content of the Universe and obtaining a better understanding of the physical process that drive galaxy formation and evolution. Using the integrated emission from unresolved galaxies or gas clouds, line intensity mapping (LIM) provides a new observational window to measure the larger properties of structure. This very promising technique motivates the community to plan for LIM experiments. We describe the development of a large field-of-view instrument, named CONCERTO, operating in the range 130-310 GHz from the APEX 12-meters telescope. CONCERTO is a low-resolution spectrometer based on the Lumped Element Kinetic Inductance Detectors technology. Spectra are obtained using a fast Fourier Transform Spectrometer (FTS), coupled to a dilution cryostat with base temperature of 0.1K. Two 2 kilo-pixels arrays of LEKID are mounted inside the cryostat that also contains the cold optics and the front-end electronics. We present in detail the technological choices leading to the instrumental concept, together with the design and fabrication of the instrument and preliminary laboratory tests on the detectors. We also give our best estimates of CONCERTO sensitivity and give predictions for two of the main scientific goals of CONCERTO, i.e. a [CII]-intensity mapping survey and observations of galaxy clusters. We provide a detail description of the instrument design. Based on realistic comparisons with existing instruments developed by our group (NIKA, NIKA2, and KISS), and on laboratory detectors characterisation, we provide an estimate of CONCERTO sensitivity on sky. Finally, we describe in detail two out of the main science goals offered by CONCERTO at APEX., Comment: Accepted for publication in Astronomy and Astrophysics

We report the design, fabrication and testing of Lumped Element Kinetic Inductance Detectors (LEKID) showing performance in line with the requirements of the next generation space telescopes operating in the spectral range from 80 to 600 GHz. This range is of particular interest for Cosmic Microwave Background (CMB) studies. For this purpose we have designed and fabricated 100-pixel arrays covering five distinct bands. These wafers have been measured via multiplexing, where a full array is read out using a single pair of lines. We adopted a custom cold black-body installed in front of the detectors and regulated at temperatures between 1 K and 20 K. We will describe in the present paper the main design considerations, the fabrication processes, the testing and the data analysis.

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., Comment: Accepted for publication in European Journal of Physics C

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 MAJORANA DEMONSTRATOR is sensitive to rare events near its energy threshold, including bosonic dark matter, solar axions, and lightly ionizing particles. In this analysis, a novel training set of low energy small-angle Compton scatter events is used to determine the efficiency of pulse shape analysis cuts, and we present updated bosonic dark matter and solar axion results from an 11.17 kg-y dataset using a 5 keV analysis threshold., Comment: 4 pages, 4 figures. Proceedings of the 16th International Conference on Topics in Astroparticle and Underground Physics (TAUP 2019), September 9-13, 2019, Toyama, Japan

The MAJORANA DEMONSTRATOR is searching for double-beta decay of $^{76}$Ge to excited states (E.S.) in $^{76}$Se using a modular array of high purity Germanium detectors. $^{76}$Ge can decay into three E.S.s of $^{76}$Se. The E.S. decays have a clear event signature consisting of a $\beta\beta$-decay with the prompt emission of one or two $\gamma$-rays, resulting in with high probability in a multi-site event. The granularity of the DEMONSTRATOR detector array enables powerful discrimination of this event signature from backgrounds. Using 21.3 kg-y of isotopic exposure, the DEMONSTRATOR has set world leading limits for each E.S. decay, with 90% CL lower half-life limits in the range of $(0.56-2.1)\cdot10^{24}$ y. In particular, for the $2\nu$ transition to the first $0^+$ E.S. of $^{76}$Se, a lower half-life limit of $0.68\cdot10^{24}$ at 90% CL was achieved.

We report on a detailed study of the optical response and $T_c-\rho$ phase diagram ($T_c$ being the superconducting critical temperature and $\rho$ the normal state resistivity of the film) of granular aluminum, combining transport measurements and a high resolution optical spectroscopy technique. The $T_c-\rho$ phase diagram is discussed as resulting from an interplay between the phase stiffness, the Coulomb repulsion and the superconducting gap $\Delta$. We provide a direct evidence for two different types of well resolved sub-gap absorptions, at $\omega_1\simeq\Delta$ and at $\Delta\lesssim\omega_2\lesssim2\Delta$ (decreasing with increasing resistivity).

The MAJORANA Collaboration is operating an array of high purity Ge detectors to search for the neutrinoless double-beta decay of $^{76}$Ge. The MAJORANA DEMONSTRATOR consists of 44.1 kg of Ge detectors (29.7 kg enriched to 88% in $^{76}$Ge) split between two modules constructed from ultra-clean materials. Both modules are contained in a low-background shield at the Sanford Underground Research Facility in Lead, South Dakota. We present updated results on the search for neutrinoless double-beta decay in $^{76}$Ge with $26.0\pm0.5$ kg-yr of enriched exposure. With the DEMONSTRATOR's unprecedented energy resolution of 2.53 keV FWHM at $Q_{\beta\beta}$, we observe one event in the region of interest with 0.65 events expected from the estimated background, resulting in a lower limit on the $^{76}$Ge neutrinoless double-beta decay half-life of $2.7\times10^{25}$ yr (90% CL) with a median sensitivity of $4.8\times10^{25}$ yr (90% CL). Depending on the matrix elements used, a 90% CL upper limit on the effective Majorana neutrino mass in the range of 200-433 meV is obtained. The measured background in the low-background configurations is $11.9\pm2.0$ counts/(FWHM t yr)., Comment: 11 pages, 11 figures

The MAJORANA DEMONSTRATOR is searching for neutrinoless double-beta decay in 76Ge using arrays of point-contact germanium detectors operating at the Sanford Underground Research Facility. Background results in the neutrinoless double-beta decay region of interest from data taken during construction, commissioning, and the start of full operations have been recently published. A pulse shape analysis cut applied to achieve this result, named AvsE, is described in this paper. This cut is developed to remove events whose waveforms are typical of multi-site energy deposits while retaining (90 +/- 3.5)% of single-site events. This pulse shape discrimination is based on the relationship between the maximum current and energy, and tuned using 228Th calibration source data. The efficiency uncertainty accounts for variation across detectors, energy, and time, as well as for the position distribution difference between calibration and $0\nu\beta\beta$ events, established using simulations., Comment: 8 pages, 8 figures

The MAJORANA DEMONSTRATOR is an experiment constructed to search for neutrinoless double-beta decay in $^{76}$Ge and to demonstrate the feasibility to deploy a large-scale experiment in a phased and modular fashion. It consists of two modules of natural and $^{76}$Ge-enriched germanium detectors totalling 44.1 kg, operating at the 4850' level of the Sanford Underground Research Facility in Lead, South Dakota, USA. Commissioning of the experiment began in June 2015, followed by data production with the full detector array in August 2016. The ultra-low background and record energy resolution achieved by the MAJORANA DEMONSTRATOR enable a sensitive neutrinoless double-beta decay search, as well as additional searches for physics beyond the Standard Model. I will discuss the design elements that enable these searches, along with the latest results, focusing on the neutrinoless double-beta decay search. I will also discuss the current status and the future plans of the MAJORANA DEMONSTRATOR, as well as the plans for a future tonne-scale $^{76}$Ge experiment., Comment: 4 pages. Proceedings of The 39th International Conference on High Energy Physics (ICHEP2018), 4-11 July, 2018, Seoul, Korea. Submitted to Proceedings of Science

The Majorana Demonstrator is an ultra low-background experiment searching for neutrinoless double-beta decay in $^{76}$Ge. The heavily shielded array of germanium detectors, placed nearly a mile underground at the Sanford Underground Research Facility in Lead, South Dakota, also allows searches for new exotic physics. We present the first limits for tri-nucleon decay-specific modes and invisible decay modes for Ge isotopes. We find a half-life limit of $4.9 \times 10^{25}$ yr for the decay $^{76}{\rm Ge(ppn)} \to {}^{73}{\rm Zn}\ e^+\pi^+$ and $4.7\times10^{25}$ yr for the decay $^{76}{\rm Ge(ppp)} \to ^{73}{\rm Cu}\ e^+\pi^+\pi^+$. The half-life limit for the invisible tri-proton decay mode of $^{76}$Ge was found to be $7.5\times10^{24}$ yr., Comment: Updated after suggested figure additions from referees

The aim of the plsRglm package is to deal with complete and incomplete datasets through several new techniques or, at least, some which were not yet implemented in R. Indeed, not only does it make available the extension of the PLS regression to the generalized linear regression models, but also bootstrap techniques, leave-one-out and repeated $k$-fold cross-validation. In addition, graphical displays help the user to assess the significance of the predictors when using bootstrap techniques. Biplots (Fig. 4) can be used to delve into the relationship between individuals and variables., Comment: 11 pages, 8 figures

We designed a completely automated Maple ($\geqslant 15$) worksheet for deriving Edgeworth and Cornish-Fisher expansions as well as the acceleration constant of the bootstrap bias-corrected and accelerated technique. It is valid for non-parametric or parametric bootstrap, of any (studentized) statistics that is -a regular enough- function of the mean of an iid sample of an absolutely continuous distribution. This worksheet allowed us to point out one error in the second-order Cornish-Fisher expansion of the studentized mean stated in Theorem 13.5 by Das Gupta in [8, p. 194] as well as lay the stress on the influence of the slight change of the normalizing constant when computing the second-order Edgeworth and Cornish-Fisher expansions of the t-distribution as stated in Theorem 11.4.2 by Lehman and Romano in [14, p. 460]. In addition, we successfully applied the worksheet to a complex maximum likelihood estimator as a first step to derive more accurate confidence intervals in order to enhance quality controls. The worksheet also features export of Maple results into R code. In addition, we provide R code to plot these expansions as well as their increasing rearrangements. All these supplemental materials are available upon request., Comment: 20 pages, 8 figures, code snippet

The MAJORANA Collaboration has completed construction and is now operating an array of high purity Ge detectors searching for neutrinoless double-beta decay ($0\nu\beta\beta$) in $^{76}$Ge. The array, known as the MAJORANA DEMONSTRATOR, is comprised of 44 kg of Ge detectors (30 kg enriched to 88% in $^{76}$Ge) installed in an ultra-low background compact shield at the Sanford Underground Research Facility in Lead, South Dakota. The primary goal of the DEMONSTRATOR is to establish a low-background design that can be scaled to a next-generation tonne-scale experiment. This work reports initial background levels in the $0\nu\beta\beta$ region of interest. Also presented are recent physics results leveraging P-type point-contact detectors with sub-keV energy thresholds to search for physics beyond the Standard Model; first results from searches for bosonic dark matter, solar axions, Pauli exclusion principle violation, and electron decay have been published. Finally, this work discusses the proposed tonne-scale $^{76}$Ge $0\nu\beta\beta$ LEGEND experiment., Comment: 6 pages, 1 figure, PANIC 2017: 21st Particles and Nuclei International Conference

The Majorana Collaboration is using an array of high-purity Ge detectors to search for neutrinoless double-beta decay in 76Ge. Searches for neutrinoless double-beta decay are understood to be the only viable experimental method for testing the Majorana nature of the neutrino. Observation of this decay would imply violation of lepton number, that neutrinos are Majorana in nature, and provide information on the neutrino mass. The Majorana Demonstrator comprises 44.1 kg of p-type point-contact Ge detectors (29.7 kg enriched in 76Ge) surrounded by a low-background shield system. The experiment achieved a high efficiency of converting raw Ge material to detectors and an unprecedented detector energy resolution of 2.5 keV FWHM at Q$_{\beta\beta}$. The Majorana collaboration began taking physics data in 2016. This paper summarizes key construction aspects of the Demonstrator and shows preliminary results from initial data., Comment: 5 pages, 2 figures. Proceeding for the "16th International Symposium on Capture Gamma-Ray Spectroscopy and Related Topics (CGS16)", 18-22 September 2017

We have fabricated planar amorphous Indium Oxide superconducting resonators ($T_c\sim2.8$ K) that are sensitive to frequency-selective radiation in the range of 7 to 10 GHz. Those values lay far below twice the superconducting gap that worths about 200 GHz. The photons detection consists in a shift of the fundamental resonance frequency. We show that the detected frequency can be adjusted by modulating the total length of the superconducting resonator. We attribute those observations to the excitation of higher-order resonance modes. The coupling between the fundamental lumped and the higher order distributed resonance is due to the kinetic inductance non-linearity with current. These devices, that we have called Sub-gap Kinetic Inductance Detectors (SKIDs), are to be distinguished from the standard Kinetic Inductance Detectors (KIDs) in which quasi-particles are generated when incident light breaks down Cooper pairs., Comment: article: 6 pages, 4 figures supplementary: 1 page, 2 figures

The introduction of crystalline defects or dopants can give rise to so-called "dirty superconductors", characterized by reduced coherence length and quasiparticle mean free path. In particular, granular superconductors such as Granular Aluminum (GrAl), consisting of remarkably uniform grains connected by Josephson contacts have attracted interest since the sixties thanks to their rich phase diagram and practical advantages, like increased critical temperature, critical field, and kinetic inductance. Here we report the measurement and modeling of circuit quantum electrodynamics properties of GrAl microwave resonators in a wide frequency range, up to the spectral superconducting gap. Interestingly, we observe self-Kerr coefficients ranging from $10^{-2}$ Hz to $10^5$ Hz, within an order of magnitude from analytic calculations based on GrAl microstructure. This amenable nonlinearity, combined with the relatively high quality factors in the $10^5$ range, open new avenues for applications in quantum information processing and kinetic inductance detectors., Comment: 7 pages, 4 figures, supplementary information

The \textsc{Majorana Demonstrator} is an ultra low-background experiment searching for neutrinoless double-beta decay in $^{76}$Ge. The heavily shielded array of germanium detectors, placed nearly a mile underground at the Sanford Underground Research Facility in Lead, South Dakota, also allows searches for new exotic physics. Free, relativistic, lightly-ionizing particles with electrical charges less than $e$ are forbidden by the standard model but predicted by some of its extensions. If such particles exist, they might be detected in the \textsc{Majorana Demonstrator} by searching for multiple- detector events with individual-detector energy depositions down to 1 keV. This search is background free and no candidate events have been found in 285 days of data taking. New direct-detection limits are set for the flux of lightly ionizing particles for charges as low as $e$/1000., Comment: final version

The MAJORANA Collaboration is searching for the neutrinoless double-beta decay of the nucleus Ge-76. The MAJORANA DEMONSTRATOR is an array of germanium detectors deployed with the aim of implementing background reduction techniques suitable for a tonne scale Ge-76-based search (the LEGEND collaboration). In the DEMONSTRATOR, germanium detectors operate in an ultra-pure vacuum cryostat at 80 K. One special challenge of an ultra-pure environment is to develop reliable cables, connectors, and electronics that do not significantly contribute to the radioactive background of the experiment. This paper highlights the experimental requirements and how these requirements were met for the MAJORANA DEMONSTRATOR, including plans to upgrade the wiring for higher reliability in the summer of 2018. Also described are requirements for LEGEND R&D efforts underway to meet these additional requirements., Comment: Proceedings of LRT 2017

The New IRAM KID Arrays 2 (NIKA2) consortium has just finished installing and commissioning a millimetre camera on the IRAM 30 m telescope. It is a dual-band camera operating with three frequency multiplexed kilo-pixels arrays of Lumped Element Kinetic Inductance Detectors (LEKID) cooled at 150 mK, designed to observe the intensity and polarisation of the sky at 260 and 150 GHz (1.15 and 2 mm). NIKA2 is today an IRAM resident instrument for millimetre astronomy, such as Intra Cluster Medium from intermediate to distant clusters and so for the follow-up of Planck satellite detected clusters, high redshift sources and quasars, early stages of star formation and nearby galaxies emission. We present an overview of the instrument performance as it has been evaluated at the end of the commissioning phase.

The Majorana Demonstrator is an experiment constructed to search for neutrinoless double-beta decays in germanium-76 and to demonstrate the feasibility to deploy a ton-scale experiment in a phased and modular fashion. It consists of two modular arrays of natural and 76Ge-enriched germanium p-type point contact detectors totaling 44.1 kg, located at the 4850 level of the Sanford Underground Research Facility in Lead, South Dakota, USA. The Demonstrator uses custom high voltage cables to bias the detectors, as well as custom signal cables and connectors to read out the charge deposited at the point contact of each detector. These low-mass cables and connectors must meet stringent radiopurity requirements while being subjected to thermal and mechanical stress. A number of issues have been identified with the currently installed cables and connectors. An improved set of cables and connectors for the Majorana Demonstrator are being developed with the aim of increasing their overall reliability and connectivity. We will discuss some of the issues encountered with the current cables and connectors as well as our improved designs and their initial performance., Comment: 5 pages, 2 figures, TAUP 2017: XV International Conference on Topics in Astroparticle and Underground Physics

The MAJORANA Collaboration has assembled an array of high purity Ge detectors to search for neutrinoless double-beta decay in $^{76}$Ge with the goal of establishing the required background and scalability of a Ge-based next-generation ton-scale experiment. The MAJORANA DEMONSTRATOR consists of 44 kg of high-purity Ge (HPGe) detectors (30 kg enriched in $^{76}$Ge) with a low-noise p-type point contact (PPC) geometry. The detectors are split between two modules which are contained in a single lead and high-purity copper shield at the Sanford Underground Research Facility in Lead, South Dakota. Following a commissioning run that started in June 2015, the full detector array has been acquiring data since August 2016. We will discuss the status of the MAJORANA DEMONSTRATOR and initial results from the first physics run; including current background estimates, exotic low-energy physics searches, projections on the physics reach of the DEMONSTRATOR, and implications for a ton-scale Ge-based neutrinoless double-beta decay search., Comment: Proceedings of TAUP 2017: XV International Conference on Topics in Astroparticle and Underground Physics (24-28 July 2017, Sudbury, ON, Canada)

The MAJORANA DEMONSTRATOR is an experiment constructed to search for neutrinoless double-beta decays in germanium-76 and to demonstrate the feasibility to deploy a large-scale experiment in a phased and modular fashion. It consists of two modular arrays of natural and $^{76}$Ge-enriched germanium detectors totalling 44.1 kg, located at the 4850' level of the Sanford Underground Research Facility in Lead, South Dakota, USA. Any neutrinoless double-beta decay search requires a thorough understanding of the background and the signal energy spectra. The various techniques employed to ensure the integrity of the measured spectra are discussed. Data collection is monitored with a thorough set of checks, and subsequent careful analysis is performed to qualify the data for higher level physics analysis. Instrumental background events are tagged for removal, and problematic channels are removed from consideration as necessary., Comment: 5 pages, 2 figures, Proceedings of TAUP 2017 - XV International Conference on Topics in Astroparticle and Underground Physics (Sudbury ON, Canada, July 24-28, 2017)

The MAJORANA DEMONSTRATOR is a neutrinoless double beta decay experiment utilizing enriched Ge-76 detectors in 2 separate modules inside of a common solid shield at the Sanford Underground Research Facility. The DEMONSTRATOR has utilized world leading assay sensitivities to develop clean materials and processes for producing ultra-pure copper and plastic components. This experiment is now operating, and initial data provide new insights into the success of cleaning and processing. Post production copper assays after the completion of Module 1 showed an increase in U and Th contamination in finished parts compared to starting bulk material. A revised cleaning method and additional round of surface contamination studies prior to Module 2 construction have provided evidence that more rigorous process control can reduce surface contamination. This article describes the assay results and discuss further studies to take advantage of assay capabilities for the purpose of maintaining ultra clean fabrication and process design., Comment: Proceedings of Low Radioactivity Techniques (LRT May 2017, Seoul)

The MAJORANA DEMONSTRATOR is a $^{76}$Ge-based neutrinoless double-beta decay ($0\nu\beta\beta$) experiment. Staged at the 4850 ft level of the Sanford Underground Research Facility, the DEMONSTRATOR operates an array of high-purity p-type point contact Ge detectors deployed within a graded passive shield and an active muon veto system. The present work concerns the two-neutrino double-beta decay mode ($2\nu\beta\beta$) of $^{76}$Ge. For Ge detectors, having superior energy resolution (0.1%), this mode poses negligible background to the $0\nu\beta\beta$ mode, even for a ton-scale experiment. However, the measurement of the $2\nu\beta\beta$ mode allows for careful systematics checks of active detector mass, enrichment fraction, and pulse shape discrimination cuts related to both the $0\nu\beta\beta$ and $2\nu\beta\beta$ decay modes. A precision measurement of the $2\nu\beta\beta$ shape also allows searches for spectral distortions, possibly indicative of new physics, including $0\nu\beta\beta\chi$. Work is underway to construct a full experimental background model enabling a Bayesian fit to the measured energy spectrum and extraction of a precise $2\nu\beta\beta$ spectrum and half-life., Comment: 5 pages, 2 figures, TAUP 2017: XV International Conference on Topics in Astroparticle and Underground Physics