Critical Temperature tuning of Ti/TiN multilayer films suitable for low temperature detectors

We present our current progress on the design and test of Ti/TiN Multilayer for use in Kinetic Inductance Detectors (KIDs). Sensors based on sub-stoichiometric TiN film are commonly used in several applications. However, it is difficult to control the targeted critical temperature $T_C$, to maintain precise control of the nitrogen incorporation process and to obtain a production uniformity. To avoid these problems we investigated multilayer Ti/TiN films that show a high uniformity coupled with high quality factor, kinetic inductance and inertness of TiN. These features are ideal to realize superconductive microresonator detectors for astronomical instruments application but also for the field of neutrino physics. Using pure Ti and stoichiometric TiN, we developed and tested different multilayer configuration, in term of number of Ti/TiN layers and in term of different interlayer thicknesses. The target was to reach a critical temperature $T_C$ around $(1\div 1.5)$ K in order to have a low energy gap and slower recombination time (i.e. low generation-recombination noise). The results prove that the superconductive transition can be tuned in the $(0.5\div 4.6)$ K temperature range properly choosing the Ti thickness in the $(0\div 15)$ nm range, and the TiN thickness in the $(5\div 100)$ nm rang

The 4 K outer cryostat for the CUORE experiment: construction and quality control

The external shell of the CUORE cryostat is a large cryogen-free system designed to host the dilution refrigerator and the bolometers of the CUORE experiment in a low radioactivity environment. The three vessels that form the outer shell were produced and delivered to the Gran Sasso underground Laboratories in July 2012. In this paper, we describe the production techniques and the validation tests done at the production site in 2012.Comment: 11 pages, 13 figures; to appear in NIM

Development of microwave superconducting microresonators for neutrino mass measurement in the HOLMES framework

The European Research Council has recently funded HOLMES, a project with the aim of performing a calorimetric measurement of the electron neutrino mass measuring the energy released in the electron capture decay of 163Ho. The baseline for HOLMES are microcalorimeters coupled to Transition Edge Sensors (TESs) read out with rf-SQUIDs, for microwave multiplexing purposes. A promising alternative solution is based on superconducting microwave resonators, that have undergone rapid development in the last decade. These detectors, called Microwave Kinetic Inductance Detectors (MKIDs), are inherently multiplexed in the frequency domain and suitable for even larger-scale pixel arrays, with theoretical high energy resolution and fast response. The aim of our activity is to develop arrays of microresonator detectors for X-ray spectroscopy and suitable for the calorimetric measurement of the energy spectra of 163Ho. Superconductive multilayer films composed by a sequence of pure Titanium and stoichiometric TiN layers show many ideal properties for MKIDs, such as low loss, large sheet resistance, large kinetic inductance, and tunable critical temperature $T_c$. We developed Ti/TiN multilayer microresonators with $T_c$ within the range from 70 mK to 4.5 K and with good uniformity. In this contribution we present the design solutions adopted, the fabrication processes and the characterization results

Large area Si low-temperature light detectors with Neganov-Luke effect

Next generation calorimetric experiments for the search of rare events rely on the detection of tiny amounts of light (of the order of 20 optical photons) to discriminate and reduce background sources and improve sensitivity. Calorimetric detectors are the simplest solution for photon detection at cryogenic (mK) temperatures. The development of silicon based light detectors with enhanced performance thanks to the use of the Neganov-Luke effect is described. The aim of this research line is the production of high performance detectors with industrial-grade reproducibility and reliability.Comment: 4 pages, 2 figure

The Future of Neutrino Mass Measurements: Terrestrial, Astrophysical, and Cosmological Measurements in the Next Decade. Highlights of the NuMass 2013 Workshop. Milano, Italy, February 4 - 7, 2013

The third Workshop of the NuMass series ("The Future of Neutrino Mass Measurements: Terrestrial, Astrophysical, and Cosmological Measurements in the Next Decade: NuMass 2013") was held at Dipartimento di Fisica "G. Occhialini, University of Milano-Bicocca in Milano, Italy, on 4-7 February 2013. The goal of this international workshop was to review the status and future of direct and indirect neutrino mass measurements in the laboratory as well as from astrophysical and cosmological observations. This paper collects most of the contributions presented during the Workshop

Exploring the Neutrinoless Double Beta Decay in the Inverted Neutrino Hierarchy with Bolometric Detectors

Neutrinoless double beta decay (0nubb) is one of the most sensitive probes for physics beyond the Standard Model, providing unique information on the nature of neutrinos. In this paper we review the status and outlook for bolometric 0nubb decay searches. We summarize recent advances in background suppression demonstrated using bolometers with simultaneous readout of heat and light signals. We simulate several configurations of a future CUORE-like bolometer array which would utilize these improvements and present the sensitivity reach of a hypothetical next-generation bolometric 0nubb experiment. We demonstrate that a bolometric experiment with the isotope mass of about 1 ton is capable of reaching the sensitivity to the effective Majorana neutrino mass (|mee|) of order 10-20 meV, thus completely exploring the so-called inverted neutrino mass hierarchy region. We highlight the main challenges and identify priorities for an R&D program addressing them.Comment: 22 pages, 15 figures, submitted to EPJ

Search for Neutrinoless Double-Beta Decay of 130^{130}Te with CUORE-0

We report the results of a search for neutrinoless double-beta decay in a 9.8~kg$\cdot$yr exposure of $^{130}$Te using a bolometric detector array, CUORE-0. The characteristic detector energy resolution and background level in the region of interest are $5.1\pm 0.3{\rm~keV}$ FWHM and $0.058 \pm 0.004\,(\mathrm{stat.})\pm 0.002\,(\mathrm{syst.})$~counts/(keV$\cdot$kg$\cdot$yr), respectively. The median 90%~C.L. lower-limit sensitivity of the experiment is $2.9\times 10^{24}~{\rm yr}$ and surpasses the sensitivity of previous searches. We find no evidence for neutrinoless double-beta decay of $^{130}$Te and place a Bayesian lower bound on the decay half-life, $T^{0\nu}_{1/2}>$~$2.7\times 10^{24}~{\rm yr}$ at 90%~C.L. Combining CUORE-0 data with the 19.75~kg$\cdot$yr exposure of $^{130}$Te from the Cuoricino experiment we obtain $T^{0\nu}_{1/2} > 4.0\times 10^{24}~\mathrm{yr}$ at 90%~C.L.~(Bayesian), the most stringent limit to date on this half-life. Using a range of nuclear matrix element estimates we interpret this as a limit on the effective Majorana neutrino mass, $m_{\beta\beta}< 270$ -- $760~\mathrm{meV}$.Comment: 6 pages, 5 figures, updated version as published in PR

Analysis Techniques for the Evaluation of the Neutrinoless Double-Beta Decay Lifetime in 130^{130}Te with CUORE-0

We describe in detail the methods used to obtain the lower bound on the lifetime of neutrinoless double-beta ($0\nu\beta\beta$) decay in $^{130}$Te and the associated limit on the effective Majorana mass of the neutrino using the CUORE-0 detector. CUORE-0 is a bolometric detector array located at the Laboratori Nazionali del Gran Sasso that was designed to validate the background reduction techniques developed for CUORE, a next-generation experiment scheduled to come online in 2016. CUORE-0 is also a competitive $0\nu\beta\beta$ decay search in its own right and functions as a platform to further develop the analysis tools and procedures to be used in CUORE. These include data collection, event selection and processing, as well as an evaluation of signal efficiency. In particular, we describe the amplitude evaluation, thermal gain stabilization, energy calibration methods, and the analysis event selection used to create our final $0\nu\beta\beta$ decay search spectrum. We define our high level analysis procedures, with emphasis on the new insights gained and challenges encountered. We outline in detail our fitting methods near the hypothesized $0\nu\beta\beta$ decay peak and catalog the main sources of systematic uncertainty. Finally, we derive the $0\nu\beta\beta$ decay half-life limits previously reported for CUORE-0, $T^{0\nu}_{1/2}>2.7\times10^{24}$ yr, and in combination with the Cuoricino limit, $T^{0\nu}_{1/2}>4.0\times10^{24}$ yr.Comment: 18 pages, 18 figures. (Version 3 reflects only minor changes to the text. Few additional details, no major content changes.

Two cases of canine gallbladder carcinoid: clinical and ultrasonographic findings

Gallbladder carcinoid is a rare neoplasia that arise from the dispersed cells of the neuroendocrine system of the biliary three. This tumour have been described in humans and dogs. In the few reports we can nd in literature, canine patients a ected by this neoplasia present a combination of symptoms such as: vomiting, weight loss, lethargy, fever, melena, anaemia, hematemesis and jaundice. Haemobilia, hemocholecyst and common bile duct dila- tion have been found in few dogs presenting gallbladder car- cinoid. Clinical-ultrasonographic ndings and long term follow up of two asymptomatic dogs a ected by gallbladder carcinoid are described. Dog 1: Mixed breed, 10 years old, 28 kg, underwent ultrasonographic examination for a routine follow up control because previously a ected by low grade splenic lymphoma. Liver was sonographically normal and a 4 cm, round shaped, inhomogeneous mass was found into the gallbladder arising absence of airway disease and of clinical signs as cough, exercise intolerance, anorexia, syncope, ascites and dysp- nea, were collected from a total of 477 medical records. All dogs included in the study underwent a complete physical and echocardiographic examination. In dogs in stage B1 or B2 that presented with cough, cough was con rmed to be due to concomitant airway disease by radiographic and echocardiographic examination in conjunction with informa- tion regarding follow-up and response to therapy. From the 477 medical records, 235 had complete infor- mation regarding clinical signs. In these 235 records, 139 symptomatic dogs were identi ed. At baseline examination, 90 (64.7%) dogs presented with cough, 48 (34.5%) with exercise intolerance, 36 (25.9%) with dyspnea, 36 (25.9%) with syncope, 25 (18%) with anorexia and 8 (5.8%) with ascites. Out of the 90 dogs that had cough, 44 (48.9%) were in stage B1 or B2, which means that in these cough was caused by concomitant airway disease. Of the 177 dogs with information regarding cardiac auscultation and murmur intensity, 156 (88.1%) had a left apical systolic murmur. Mur- mur grades were mainly between 2 and 5 (95.6%). The mean SBP was 149.5 \ub1 26.51 mmHg (n= 63), and the mean HR was 135 \ub1 37.9 bpm (n= 477). The ndings of this study regarding clinical signs reported are in agreement with the results from previous studies. The concomitant presence of airway disease seems to represent the higher risk factor for coughing in dogs with MMVD. There- fore, this should be taken into account when considering diagnosis and clinical management of these dogs. from its wall. This mass presented a massive Doppler vascu- lar signal. Bile was hypoechoic and inhomogeneous with a small amount of biliary sludge. Common bile duct (CBD) diameter was normal (&lt; 3 mm). Visceral lymphadenopathy was not reported Dog 2: English Bulldog, 9 years old, 30 kg, underwent ultrasonographic examination because of a routine control of urate cystolithiasis. Liver was sonographically normal and a 1,5 cm, round shaped, inhomogeneous mass with regular margins was found into the gallbladder. This mass pre- sented a massive Doppler vascular signal. Fluid content of gallbladder was anechoic. CBD diameter was normal (&lt; 3 mm). Visceral lymphadenopathy was not reported. Dogs underwent laparotomic cholecystectomy and hepatic biopsy. Any abdominal lesion was found during sur- gery, the patency of CBD was veri ed with a retrograde catheterization and no blood or clots were found into the gallbladder or biliary three. Histology and immunohistochemistry con rmed the diagnosis of gallbladder carcinoid. Hepatic biopsy did not reveal any alteration except from a mild portal hepatitis. Dogs recovered well and they remained asymptomatic; they were sonographically evaluated 3 and 12 months after surgery and no abnormalities attributable to metastasis were found. However both dogs presented a CBD dilation (almost 1 cm) without any sign of post-hepatic jaundice. CBD dilation have been described in humans with an history of cholecystectomy and it seems to be related to senior age