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Passive imaging of concealed objects at stand-off distances in excess of a few meters requires both excellent spatial, thermal and temporal resolution from the terahertz imaging system. The combination of these requirements while keeping the overall system cost at a reasonable level has been the motivation for this joint work. The THz imaging system under development is capable of sub-Kelvin NETD at video frame rates. In this paper we report the first imaging results from a 16-pixel array of superconducting antenna-coupled NbN vacuum-bridge microbolometers, operated within a cryogen-free, turn-key refrigerator. In addition to the system overview, we shall also address the uniformity of the detectors and present passive indoors raster-scanned imagery.

To detect the decay via electron capture of 71Ge, which is produced by the interaction of solar neutrinos on 71Ga, a cryogenic detector, exhibiting both good energy resolution and high detection efficiency (4pi) was developed. The overall efficiency of Gallium based radiochemical solar neutrino experiments can be increased drastically, if this type of detector is introduced in such an experiment. The low-temperature detectors in question are based on superconducting phase transition thermometers (TESs). A specially developed glueing technique allows thermal deposition of 71Ge onto the low-temperature detector, which is completely decoupled from the production process of the TES. Furthermore the TESs can be connected via the glueing technique to various absorber materials. Longterm measurements with reactor-activated 71Ge were successfully performed in an especially set up cryostat in the underground laboratory in Garching. In addition to that, Ir/Au-microcalorimeters using Sn-absorbers achieved a worldwide best energy resolution (for Ir/Au TESs)) of 5.9eV at 5.9keV. Zum Nachweis des Germanium-Zerfalls durch Elektroneinfang an 71Ge, das aus 71Ga durch solare Neutrinos gebildet wird, wurden Tieftemperaturdetektoren mit guter Energieauflösung und voller (4pi) Nachweiseffizienz entwickelt. Dadurch kann die Gesamteffizienz der Experimente zum Nachweis solarer Neutrinos mit Gallium wesentlich verbessert werden. Diese Detektoren verwenden supraleitende Phasenübergangsthermometer (PT). Durch eine speziell entwickelte Klebung wird ermöglicht, die thermische Abscheidung von 71Ge von der Herstellung der PT vollständig zu entkoppeln. Weiterhin können die PT mit unterschiedlichen Absorbermaterialien verbunden werden. Langzeitstabile Messungen mit reaktoraktiviertem 71Ge wurden in einem eigens dafür aufgebauten Kryostaten im Untergrundlabor Garching erfolgreich durchgeführt. Auf der Klebetechnik aufbauende Ir/Au-Mikrokalorimeter mit supraleitendem Sn-Absorber erzielten ferner eine weltweit beste Energieauflösung von 5.9eV bei 5.9keV.

The effects of prolonged annealing at elevated temperatures have been investigated in a 53 cm(3) closed-end coaxial high purity germanium detector in the reverse electrode configuration. The detector was multiply annealed at 100 degrees C in block periods of 7 days. After each anneal cycle it was cooled to 77 K and the relative efficiency, peak channel location and FWHM energy resolution measured at 6 gamma-ray energies. At the present time, the detector has completed 16 anneal cycles. It was found that above similar to 662 keV the photopeak efficiency decreased almost linearly at a rate of similar to 1.5% per anneal cycle, although the energy resolution and centroid (and therefore charge collection efficiency) remained unchanged. The change in detection efficiency is attributed to the expansion of the inner n+ contact due to the thermal drive-in of Li ions into the bulk. The rate is found to follow a power-law dependence in agreement with that expected from Fick's diffusion laws. Using these data, we have derived a simple 1-D phenomenological model in which the n+ contact thickness is simply related to the Li diffusion length. For annealing at 100 degrees C, the thickness of the n+ contact, d, as a function of the annealing time, t, can be described semi-empirically by d(mm)=0.231xt(days)(1/2).

Die radiochemischen Gallium-Experimente GALLEX/GNO und SAGE haben zur Lösung des solaren Neutrinoproblems und der Entdeckung von Neutrino-Oszillationen wesentlich beigetragen. Mit dem Einsatz eines neuen hocheffizienten Detektorkonzepts, das auf Tieftemperaturdetektoren beruht, kann das Potential der Experimente weiter erheblich verbessert werden. Im Rahmen dieser Arbeit wurden die Daten dieser Experimente weiter analysiert und mit dem neuen Detektorkonzept Messungen durchgeführt, u.a. eine Langzeitmessung des 71Ge-Zerfalls. Die neue, hocheffiziente Nachweistechnik für niederenergetische Röntgen-Strahlung kann auch in einer Vielzahl weiterer Aktivitätsanalysen Anwendung finden. The radiochemical Gallium experiments GALLEX/GNO and SAGE have contributed considerably to the solution of the solar neutrino problem and the discovery of neutrino oscillations. Using a new, highly efficient detector concept based on low temperature detectors, the potential of the experiments can be improved substantially. In this work, the data analysis of the experiments was continued and measurements using the new detector concept were performed, e.g. a long-term measurement of the decay of 71Ge. The new, highly efficient detection method for low-energy X-rays is applicable in a variety of different activity analyses.

We report the present results of the CUORICINO experiment, a cryogenic experiment on neutrinoless Double Beta Decay (DBD) of 130Te consisting of an array of 62 TeO2 crystals with a total active mass of 40:7 kg. The array is framed inside a dilution refrigerator, heavily shielded against environmental radioactivity and high-energy neutrons, and it is operated at a temperature of 8mK in the Gran Sasso Underground Laboratory. After several improvements the live time of the experiment is near 75%.

After 3 years of project study and development, a 40 kg, 62-crystal, thermal detector array CUORICINO started last February. It is supposed to test the two claimed, but still not confirmed, evidences in Dark Matter and in Double Beta Decay (DBD) reported in the last few years and it will have a first glance on Solar Axion. The technical goals that were forseen for this experiment would be the confirmation on the feasibility of the CUORE experiment, a 1 ton multipurpose experiment with bolometers, that could open a new era in DBD physics. © 2003 Elsevier B.V. All rights reserved.

The LUMINEU program aims at performing a pilot experiment on neutrinoless double beta decay of 100Mo using radiopure ZnMoO4 crystals operated as cryogenic scintillating bolometers. Growth of high quality radiopure crystals is a complex task, since there are no commercial molybdenum compounds available with the required level of purity and radioactive contamination. This paper discusses approaches to purify molybdenum and synthesize compounds for high quality radiopure ZnMoO4 crystal growth. A combination of a double sublimation (with addition of zinc molybdate) with subsequent recrystallization in aqueous solutions (using zinc molybdate as a collector) was used. Zinc molybdate crystals up to 1.5 kg were grown by the low-thermal-gradient Czochralski technique; their optical, luminescent, diamagnetic, thermal and bolometric properties were tested.

During a Double Beta Decay experiment performed at Laboratori Nazionali del Gran Sasso, a 274 hours low-threshold background spectra was collected with a 340 g TeO2 detector. The MIBETA experiment consists of 20 Tellurium oxide crystals working as bolometers at T = 10 mK in a dilution refrigerator. We present here the analysis carried out on a single detector to search for possible WIMP signal. The values of parameters which are essential in the search for WIMP's, like energy resolution (similar to 2 keV), energy threshold (10 keV) and nuclear quenching factor (similar or equal to 1) have been experimentally determined and are discussed in detail. The exclusion plot of the spin-independent cross section of WIMP's on the nuclei is reported.

A massive bolometer with a 760 g TeO2 crystal as energy absorber, the largest employed underground, has been realized and operated in the Gran Sasso Underground Laboratory for γ- and α-ray spectroscopy. A new system of mechanical suspensions was implemented to reduce vibration and thermal noise, and special care was put to the read-out electronics. As a consequence the FWHM resolution for high-energy γ-rays became comparable to that of Germanium diodes. The 4.2 keV average FWHM resolution for the 5407 keV line is the best ever obtained for α particles with any type of detector.

Capacitive devices are customarily used as probes to measure the level of noble liquids in detectors operated for neutrino studies and dark matter searches. In this work we describe the use of a high-temperature superconducting material as an alternative to control the level of a cryogenic noble liquid. Lab measurements indicate that the superconductor shows a linear behaviour, a high degree of stability and offers a very accurate determination of the liquid volume. This device is therefore a competitive instrument and shows several advantages over conventional level meters., This work has been carried out under the auspices of the Spanish Ministry of Education & Science (Grant FPA2006-00684).

There is growing interest in the use of noble liquid detectors to study particle properties and search for new phenomena. In particular, they are extremely suitable for performing direct searches for dark matter. In this kind of experiments, the light produced after an interaction within the sensitive volume is usually read-out by photomultipliers. The need to go to masses in the tonne scale to explore deeper regions of the parameter space, calls for the use of large area photomultipliers. In this paper we address the need to perform laboratory calibration measurements of these large photomultipliers, in particular to characterize its behaviour at cryogenic temperatures where no reference from the manufacturer is available. We present comparative tests of phototubes from two companies. The tests are performed in conditions similar to those of operation in a real experiment. Measurements of the most relevant phototube parameters (quantum efficiency, gain, linearity, etc.) both at room and liquid Argon temperatures are reported. The results show that the studied phototubes comply with the stringent requirements posed by current dark matter searches performed with noble-liquid detectors., This work has been supported by CICYT Grants FPA-2006-00684, FPA-2002-01835 and FPA- 2005-07605-C02-01.

© 2017 IOP Publishing Ltd and Sissa Medialab srl. CUORE is a cryogenic detector that will be operated at LNGS to search for neutrinoless double beta decay (0ββ) of 130Te. The detector installation was completed in summer 2016. Before the installation, several cold runs were done to test the cryogenic system performance. In the last cold run the base temperature of 6.3mK was reached in stable condition. CUORE-0, a CUORE prototype, has proven the feasibility of CUORE, demonstrating that the target background of 0.01 counts/keV/kg/y and the energy resolution of 5 keV are within reach.

Our team is developing the Cryogenic Anticoincidence Detector (CryoAC) of the ATHENA X-ray Integral Field Unit (X-IFU). It is a 4-pixels TES-based detector, which will be placed less than 1 mm below the main TES array detector. We are now producing the CryoAC Demonstration Model (DM): a single pixel prototype able to probe the detector critical technologies, i.e. the operation at 50 mK thermal bath, the threshold energy at 20 keV and the reproducibility of the thermal conductance between the suspended absorber and the thermal bath. This detector will be integrated and tested in our cryogenic setup at INAF/IAPS, and then delivered to SRON for the integration in the X-IFU Focal Plane Assemby (FPA) DM. In this paper we report the status of the CryoAC DM development, showing the main result obtained with the last developed prototype, namely AC-S9. This is a DM-like sample, which we have preliminary integrated and tested before performing the final etching process to suspend the silicon absorber. The results are promising for the DM, since despite the limitations due to the absence of the final etching (high thermal capacity, high thermal conductance, partial TES surface coverage), we have been able to operate the detector with TB = 50 mK and to detect 6 keV photons, thus having a low energy threshold fully compatible with our requirement (20 keV)., Comment: Proceeding of the SPIE Astronomical Telescopes + Instrumentation 2018

Author(s): Santone, D; Alduino, C; Alfonso, K; Artusa, DR; Avignone, FT; Azzolini, O; Banks, TI; Bari, G; Beeman, JW; Bellini, F; Bersani, A; Biassoni, M; Branca, A; Brofferio, C; Bucci, C; Camacho, A; Caminata, A; Canonica, L; Cao, XG; Capelli, S; Cappelli, L; Carbone, L; Cardani, L; Carniti, P; Casali, N; Cassina, L; Chiesa, D; Chott, N; Clemenza, M; Copello, S; Cosmelli, C; Cremonesi, O; Creswick, RJ; Cushman, JS; D'Addabbo, A; Dafinei, I; Davis, CJ; Dell'Oro, S; Deninno, MM; Di Domizio, S; Di Vacri, ML; Drobizhev, A; Fang, DQ; Faverzani, M; Fernandes, G; Ferri, E; Ferroni, F; Fiorini, E; Franceschi, MA; Freedman, SJ; Fujikawa, BK; Giachero, A; Gironi, L; Giuliani, A; Gladstone, L; Gorla, P; Gotti, C; Gutierrez, TD; Haller, EE; Han, K; Hansen, E; Heeger, KM; Hennings-Yeomans, R; Hickerson, KP; Huang, HZ; Kadel, R; Keppel, G; Kolomensky, YG; Leder, A; Ligi, C; Lim, KE; Liu, X; Ma, YG; Maino, M; Marini, L; Martinez, M; Maruyama, RH; Mei, Y; Moggi, N; Morganti, S; Mosteiro, PJ; Napolitano, T; Nones, C; Norman, EB; Novati, V | Abstract: CUORE is a cryogenic detector that will be operated at LNGS to search for neutrinoless double beta decay (0ββ) of 130Te. The detector installation was completed in summer 2016. Before the installation, several cold runs were done to test the cryogenic system performance. In the last cold run the base temperature of 6.3mK was reached in stable condition. CUORE-0, a CUORE prototype, has proven the feasibility of CUORE, demonstrating that the target background of 0.01 counts/keV/kg/y and the energy resolution of 5 keV are within reach.

Liquid Argon (LAr) is one of the most widely used scintillators in particle detection, due to its low cost, high availability and excellent scintillation properties. A large number of experiments in the neutrino sector are based around using LAr in one or more Time Projection Chambers (TPCs), leading to high resolution three-dimensional particle reconstruction. In this paper, we review and summarise a number of these Liquid Argon Time Projection Chamber (LArTPC) experiments, and briefly describe the specific technologies that they currently employ. This includes single phase LAr experiments (ICARUS T600, MicroBooNE, SBND, LArIAT, DUNE-SP, ProtoDUNE-SP, ArgonCube and Vertical Drift) and dual phase LAr experiments (DUNE-DP, WA105, ProtoDUNE-DP and ARIADNE). We also discuss some new avenues of research in the field of LArTPC readout, which show potential for wide-scale use in the near future., Comment: 59 pages, 54 figures