Ge Detectors and 0νββ0\nu\beta\beta: The Search for Double Beta Decay with Germanium Detectors: Past, Present and Future

High Purity Germanium Detectors have excellent energy resolution; the best among the technologies used in double beta decay. Since neutrino-less double beta decay hinges on the search for a rare peak upon a background continuum, this strength has enabled the technology to consistently provide leading results. The Ge crystals at the heart of these experiments are very pure; they have no measurable U or Th contamination. The added efforts to reduce the background associated with electronics, cryogenic cooling, and shielding have been very successful, leading to the longevity of productivity. The first experiment published in 1967 by the Milan group of Fiorini, established the benchmark half-life limit $>3\times10^{20}$ yr. More recently, the \MJ\ and GERDA collaborations have developed new detector technologies that optimize the pulse waveform analysis. As a result, the GERDA collaboration refuted the claim of observation with a revolutionary approach to shielding by immersing the detectors directly in radio-pure liquid argon. In 2018, the \MJ\ collaboration, using a classic vacuum cryostat and high-Z shielding, achieved a background level near that of GERDA by developing very pure materials for use nearby the detectors. Together, GERDA and \MJ\ have provided limits approaching $10^{26}$ yr. In this article, we elaborate on the historical use of Ge detectors for double beta decay addressing the strengths and weaknesses. We also summarize the status and future as many \MJ\ and GERDA collaborators have joined with scientists from other efforts to give birth to the LEGEND collaboration. LEGEND will exploit the best features of both experiments to extend the half-life limit beyond $10^{28}$ yr with a ton-scale experiment.Comment: Invited submission to Frontiers in Physic

The MAJORANA 76Ge neutrino less double-beta decay project: A brief update

At present, MAJORANA is a research and development (R&D) project to investigate the feasibility and cost of constructing and operating a one ton decay experiment with ~1000 kg of Ge detectors fabricated from germanium enriched to 86% in . The study will include three separate cryostats with various types of detectors: un-segmented, un-segmented point-contact, minimally segmented, and highly segmented. One cryostat will contain at least 30 kg of enriched (preferably point-contact) detectors. The performance of the cryostats and detectors as well as background levels will be investigated. The goal of the demonstrator project is to reach a discovery sensitivity of ~ 1026 y.Comment: 3 pages, no figure

Calorimeter R&D for the SuperNEMO Double Beta Decay Experiment

SuperNEMO is a next-generation double beta decay experiment based on the successful tracking plus calorimetry design approach of the NEMO3 experiment currently running in the Laboratoire Souterrain de Modane (LSM). SuperNEMO can study a range of isotopes, the baseline isotopes are 82Se and possibly 150Nd. The total isotope mass will be 100-200 kg. A sensitivity to neutrinoless double beta decay half-life greater than 10e26 years can be reached which gives access to Majorana neutrino masses of 50-100 meV. One of the main challenges of the SuperNEMO R&D is the development of the calorimeter with an unprecedented energy resolution of 4% FWHM at 3 MeV (Qbb value of 82Se).Comment: Presented at 13th International Conference on Calorimetry in High Energy Physics (CALOR08), Pavia, Italy, 26-30 May 200

Coherent Neutral Current Neutrino-Nucleus Scattering at a Spallation Source; a Valuable Experimental Probe

The coherent contribution of all neutrons in neutrino nucleus scattering due to the neutral current is examined considering the Spallation Neutron Source (SNS) as a source of neutrinos. SNS is a prolific pulsed source of electron and muon neutrinos as well as muon antineutrinos.Comment: 15 LaTex pages, 14 figures, 3 Table

Theoretical Estimate of the Sensitivity of the CUORE Detector to Solar Axions

In this paper we calculate the potential sensitivity of the CUORE detector to axions produced in the Sun through the Primakoff process and detected by the inverse coherent Bragg-Primakoff process. The conversion rate is calculated using density functional theory for the electron density and realistic expectations for the energy resolution and background of CUORE. Monte Carlo calculations for $5~$y$\times741~$kg=$3705~$kg y of exposure are analyzed using time correlation of individual events with the theoretical time-dependent counting rate and lead to an expected limit on the axion-photon coupling $g_{a\gamma\gamma}<3.83\times 10^{-10}~GeV^{-1}$ for axion masses less than $100$ eV.Comment: Corrected typos and made the form of the references unifor

Relevance of Ion-Channeling for Direct DM Detection

The channeling of the recoiling nucleus in crystalline detectors after a WIMP collision would produce a larger scintillation or ionization signal in direct detection experiments than otherwise expected. I present estimates of the importance of this effect for the total direct detection rate and the daily modulation of the signal using analytic models produced in the 1960's and 70's to describe the effects of channeling and blocking in crystals.Comment: Talk given at the TAUP 2009 conference, Rome, Italy, July 1-5 2009. 3 pages, 4 figures. jpconf.cls and jpconf11.clo files need to typeset the tex fil

The experimental challenge of detecting solar axion-like particles to test cosmological ALP-photon oscillation hypothesis

We consider possible experimental tests of recent hypotheses suggesting that TeV photons survive the pair production interaction with extragalactic background light over cosmological distances by converting to axion-like particles (ALPs) in galactic magnetic fields. We show that proposed giant ultra-low background scintillation detectors will even have a difficult time reaching the present CAST sensitivity, which is one to two orders of magnitude less sensitive than necessary for a meaningful test of the ALP-photon oscillation hypothesis. Potential alternative tests are briefly discussed.Comment: 4 pages, no figure