CMOS compatible athermal silicon microring resonators

Silicon photonics promises to alleviate the bandwidth bottleneck of modern day computing systems. But silicon photonic devices have the fundamental problem of being highly sensitive to ambient temperature fluctuations due to the high thermo-optic (TO) coefficient of silicon. Most of the approaches proposed to date to overcome this problem either require significant power consumption or incorporate materials which are not CMOS-compatible. Here we demonstrate a new class of optical devices which are passively temperature compensated, based on tailoring the optical mode confinement in silicon waveguides. We demonstrate the operation of a silicon photonic resonator over very wide temperature range of greater than 80 degrees. The fundamental principle behind this work can be extended to other photonic structures such as modulators, routers, switches and filters.Comment: 9 pages, 4 figure

Status of CUORE Experiment and latest results from CUORE-0

Neutrinoless Double Beta Decay (0νββ) is a rare nuclear transition that if it occurs at all it will be very important for the exploration of the inverted hierarchy region of the neutrino mass pattern. The Cryogenic Underground Observatory for Rare Events (CUORE) is an experiment that aims to search for such a transition in 130Te together with other rare processes. In the present paper we will describe the basic features of CUORE Experiment, the status of the experiment as well as the latest results obtained from CUORE-0 detector, a smaller scale experiment constructed to test and demonstrate the expected performances of CUOR

The CUORE Cryostat: A 1-Ton Scale Setup for Bolometric Detectors

The cryogenic underground observatory for rare events (CUORE) is a 1-ton scale bolometric experiment whose detector consists of an array of 988 TeO2 crystals arranged in a cylindrical compact structure of 19 towers. This will be the largest bolometric mass ever operated. The experiment will work at a temperature around or below 10 mK. CUORE cryostat consists of a cryogen-free system based on pulse tubes and a custom high power dilution refrigerator, designed to match these specifications. The cryostat has been commissioned in 2014 at the Gran Sasso National Laboratories and reached a record temperature of 6 mK on a cubic meter scale. In this paper, we present results of CUORE commissioning runs. Details on the thermal characteristics and cryogenic performances of the system will be also given.Comment: 7 pages, 2 figures, LTD16 conference proceedin

CUORE and CUORE-0 experiments

Neutrino oscillation experiments proved that neutrinos have mass and this enhanced the interest in neutrinoless double-beta decay (0νββ). The observation of this very rare hypothetical decay would prove the leptonic number violation and would give us indications about neutrinos mass hierarchy and absolute mass scale. CUORE (Cryogenic Underground Observatory for Rare Events) is an array of 988 crystals of TeO2, for a total sensitive mass of 741kg. Its goal is the observation of 0νββ of 130Te. The crystals, placed into the a dilution cryostat, are operated as bolometers at a temperature close to 10mK. CUORE commissioning phase has been concluded recently in Gran Sasso National Laboratory, Italy, and data taking is expected to start in spring 2017. If target background rate is reached (0.01counts/day/keV/kg), the sensibility of CUORE will be, in five years of data taking, T1/2 - 1026years (1σ CL). In order to test the quality of materials and optimize the construction procedures, the collaboration realized CUORE-0, that took data from spring of 2013 to summer 2015. Here, after a brief description of CUORE, I report its commissioning status and CUORE-0 results

Results from the CUORE experiment

The Cryogenic Underground Observatory for Rare Events (CUORE) is the first bolometric experiment searching for neutrinoless double beta decay that has been able to reach the 1-ton scale. In this talk we present the neutrinoless doube beta decay results of CUORE from examining a total TeO2 exposure of 86.3 kg yr, characterized by an effective energy resolution of 7.7 keV FWHM and a background in the region of interest of 0.014 counts/(keV kg yr). In this physics run, CUORE placed a lower limit on the decay half-life of 130Te > 1.3×1025 yr (90% C.L.). We then discuss the additional improvements in the detector performance achieved in 2018 and the latest update on the evaluation of the background budget

Results from the CUORE experiment

Neutrinoless double beta decay (0νββ) is a rare, second-order nuclear transition that occurs only if neutrinos are massive Majorana particles or through new physics beyond Standard Model. This process explicitly violates the lepton number (L) by two units and, therefore, the observation of 0νββ would demonstrate that L is not a symmetry of nature. Combined with flavour mixing and cosmological measurements, it can provide unique contraints on neutrino mass scale and establish whether neutrinos are Dirac or Majorana particles. The Cryogenic Underground Observatory for Rare Events (CUORE) is an experiment located at the LNGS searching for 0νββ decay of 130Te. CUORE exploits the bolometric technique to reach high resolution around the Q-value (2527.5 keV). It consists of an array of 988 natural TeO2 cubic crystals grouped into 19 towers. With a total active mass of 742 kg (∼206 kg of 130Te), CUORE is operated at very low temperature with a new 3He/4He refrigerator. Data taking started at the beginning of 2017. After a brief introduction on the detector and the way data analysis is performed, I describe CUORE first results for the search of the 0νββ decay that were published in March 2018

The CUORE cryostat: an infrastructure for rare event searches at millikelvin temperatures

The CUORE experiment is the world's largest bolometric experiment. The detector consists of an array of 988 TeO2 crystals, for a total mass of 742 kg. CUORE is presently taking data at the Laboratori Nazionali del Gran Sasso, Italy, searching for the neutrinoless double beta decay of 130Te. A large custom cryogen-free cryostat allows reaching and maintaining a base temperature of about 10 mK, required for the optimal operation of the detector. This apparatus has been designed in order to achieve a low noise environment, with minimal contribution to the radioactive background for the experiment. In this paper, we present an overview of the CUORE cryostat, together with a description of all its sub-systems, focusing on the solutions identified to satisfy the stringent requirements. We briefly illustrate the various phases of the cryostat commissioning and highlight the relevant steps and milestones achieved each time. Finally, we describe the successful cooldown of CUORE

Measurement of the Two-Neutrino Double Beta Decay Half-life of 130^{130}Te with the CUORE-0 Experiment

We report on the measurement of the two-neutrino double beta decay half-life of $^{130}$Te with the CUORE-0 detector. From an exposure of 33.4 kg$\cdot$y of TeO$_2$, the half-life is determined to be $T_{1/2}^{2\nu}$ = [8.2 $\pm$ 0.2 (stat.) $\pm$ 0.6 (syst.)] $\times$ 10$^{20}$y. This result is obtained after a detailed reconstruction of the sources responsible for the CUORE-0 counting rate, with a specific study of those contributing to the $^{130}$Te neutrinoless double beta decay region of interest.Comment: Corrected typo in section 9: 3.43E5 Bq/kg should have read 3.43E-5 Bq/k

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.

The CUORE and CUORE-0 experiments at LNGS

The Cryogenic Underground Observatory for Rare Events (CUORE) is the first bolometric experiment searching for neutrinoless double beta decay that has been able to reach the 1-ton scale. The detector consists of an array of 988 TeO2 crystals arranged in a cylindrical compact structure of 19 towers. The construction of the experiment and, in particular, the installation of all towers in the cryostat was completed in August 2016 and commissioning started in fall 2016. The experiment has completed the pre-operation phase and is currently in data taking. We present here the achievements of CUORE during the commissioning phase and the limit on the 130Te half-life for the neutrinoless double beta decay that has been released after the first 3 weeks of collected data. Physics results from CUORE-0 will also be updated