Nuclear physics for geo-neutrino studies

Geo-neutrino studies are based on theoretical estimates of geo-neutrino spectra. We propose a method for a direct measurement of the energy distribution of antineutrinos from decays of long-lived radioactive isotopes. We present preliminary results for the geo-neutrinos from Bi-214 decay, a process which accounts for about one half of the total geo-neutrino signal. The feeding probability of the lowest state of Bi-214 - the most important for geo-neutrino signal - is found to be p_0 = 0.177 \pm 0.004 (stat) ^{+0.003}_{-0.001} (sys), under the hypothesis of Universal Neutrino Spectrum Shape (UNSS). This value is consistent with the (indirect) estimate of the Table of Isotopes (ToI). We show that achievable larger statistics and reduction of systematics should allow to test possible distortions of the neutrino spectrum from that predicted using the UNSS hypothesis. Implications on the geo-neutrino signal are discussed.Comment: 8 pages RevTex format, 8 figures and 2 tables. Submitted to PR

Development of a very low-noise cryogenic pre-amplifier for large-area SiPM devices

Silicon Photomultipliers (SiPMs) are an excellent candidate for the development of large-area light sensors. Large SiPM-based detectors require low-noise pre-amplifiers to maximize the signal coupling between the sensor and the readout electronics. This article reports on the development of a low-noise transimpedance amplifier sensitive to single-photon signals at cryogenic temperature. The amplifier is used to readout a 1 cm$^{2}$ SiPM with a signal to noise ratio in excess of 40

Cryogenic Characterization of FBK HD Near-UV Sensitive SiPMs

We report on the characterization of near-ultraviolet high density silicon photomultiplier (\SiPM) developed at Fondazione Bruno Kessler (\FBK) at cryogenic temperature. A dedicated setup was built to measure the primary dark noise and correlated noise of the \SiPMs\ between 40 and 300~K. Moreover, an analysis program and data acquisition system were developed to allow the precise characterization of these parameters, some of which can vary up to 7 orders of magnitude between room temperature and 40~K. We demonstrate that it is possible to operate the \FBK\ near-ultraviolet high density \SiPMs\ at temperatures lower than 100~K with a dark rate below 0.01 cps/mm$^2$ and total correlated noise probability below 35\% at an over-voltage of 6~V. These results are relevant for the development of future cryogenic particle detectors using \SiPMs\ as photosensors

Development of a Novel Single-Channel, 24 cm 2

We report on the realization of a novel SiPM-based, cryogenic photosensor with an active area of 24 cm$^2$ that operates as a single-channel analog detector. The device is capable of single photon counting with a signal to noise ratio better than 13, a dark rate lower than $10^{-2}$ cps/mm$^2$ and an overall photon detection efficiency significantly larger than traditional photomultiplier tubes. This development makes SiPM-based photosensors strong candidates for the next generation of dark matter and neutrino detectors, which will require multiple square meters of photosensitive area, low levels of intrinsic radioactivity and a limited number of detector channels

Development of a Novel Single-Channel, 24 cm(2), SiPM-Based, Cryogenic Photodetector

We report on the realization of a novel silicon photomultiplier (SiPM)-based, cryogenic photosensor with an active area of 24 cm(2) that operates as a single-channel analog detector. The device is capable of single-photon counting with a signal-to-noise ratio better than 13, a dark rate lower than 10(-2) Hz/mm(2), and an overall photon detection efficiency significantly larger than traditional photomultiplier tubes. This development makes SiPM-based photosensors strong candidates for the next generation of dark matter and neutrino detectors, which will require multiple square meters of photosensitive area, low levels of intrinsic radioactivity, and a limited number of detector channels