arXiv subjects

P. Picchi

Publications and source records attributed to P. Picchi.

47 records · Page 3Linked to original sources

arXiv2005

A Study of the Operation of Especially Designed Photosensitive Gaseous Detectors at Cryogenic Temperatures

In some experiments and applications there is need for large-area photosensitive detectors to operate at cryogenic temperatures. Nowadays, vacuum PMs are usually used for this purpose. We have developed special designs of planar photosensitive gaseous detectors able to operate at cryogenic temperatures. Such detectors are much cheaper PMs and are almost insensitive to magnetic fields. Results of systematic measurements of their quantum efficiencies, the maximum achievable gains and long-term stabilities will be presented. The successful operation of these detectors open realistic possibilities in replacing PMs by photosensitive gaseous detectors in some applications dealing with cryogenic liquids; for example in experiments using noble liquid TPCs or noble liquid scintillating calorimeters.

physics.ins-det↗

arXiv2005

Photosensitive Gaseous Detectors for Cryogenic Temperature Applications

There are several proposals and projects today for building LXe Time Projection Chambers (TPCs) for dark matter search. An important element of these TPCs are the photomultipliers operating either inside LXe or in vapors above the liquid. We have recently demonstrated that photosensitive gaseous detectors (wire type and hole-type) can operate perfectly well until temperatures of LN2. In this paper results of systematic studies of operation of the photosensitive version of these detectors (combined with reflective or semi-transparent CsI photocathodes) in the temperature interval of 300-150 K are presented. In particular, it was demonstrated that both sealed and flushed by a gas detectors could operate at a quite stable fashion in a year/time scale. Obtained results, in particular the long-term stability of photosensitive gaseous detectors, strongly indicate that they can be cheap and simple alternatives to photomultipliers or avalanche solid-state detectors in LXe TPC applications.

physics.ins-det↗

arXiv2004

The Successful Operation of Hole-type Gaseous Detectors at Cryogenic Temperatures

We have demonstrated that hole-type gaseous detectors, GEMs and capillary plates, can operate up to 77 K. For example, a single capillary plate can operate at gains of above 10E3 in the entire temperature interval between 300 until 77 K. The same capillary plate combined with CsI photocathodes could operate perfectly well at gains (depending on gas mixtures) of 100-1000. Obtained results may open new fields of applications for capillary plates as detectors of UV light and charge particles at cryogenic temperatures: noble liquid TPCs, WIMP detectors or LXe scintillating calorimeters and cryogenic PETs.

physics.ins-det↗

arXiv2004

The development of gaseous detectors with solid photocathodes for low temperature

There are several applications and fundamental research areas which require the detection of VUV light at cryogenic temperatures. For these applications we have developed and successfully tested special designs of gaseous detectors with solid photocathodes able to operate at low temperatures: sealed gaseous detectors with MgF2 windows and windowless detectors. We have experimentally demonstrated, that both primary and secondary (due to the avalanche multiplication inside liquids) scintillation lights could be recorded by photosensitive gaseous detectors. The results of this work may allow one to significantly improve the operation of some noble liquid gas TPCs.

physics.ins-det↗

arXiv2001

Effects of neutrino oscillations on the supernova signal in LVD

We study the impact of neutrino oscillations on the supernova neutrino signal in the Large Volume Detector (LVD). The number of expected events for a galactic supernova (D=10 kpc) is calculated, assuming neutrino masses and mixing that explain solar and atmospheric neutrino results. The possibility to detect neutrinos in different channels makes LVD sensitive to different scenarios for neutrino properties, such as normal or inverted neutrino mass hierarchy, and/or adiabatic or non adiabatic MSW resonances associated to U(e3). Of particular importance are the charged current reactions on carbon: oscillations increase by almost one order of magnitude the number of events expected from this channel.

astro-ph↗

arXiv2001

Detection of the primary scintillation light from dense Ar, Kr and Xe with novel photosensitive gaseous detectors

The detection of primary scintillation light in combination with the charge or secondary scintillation signals is an efficient technique to determine the events t=0 as well as particle / photon separation in large mass TPC detectors filled with noble gases and/or condensed noble gases. The aim of this work is to demonstrate that costly photo-multipliers could be replaced by cheap novel photosensitive gaseous detectors: wire counters, GEMs or glass capillary tubes coupled with CsI photocathodes. We have performed systematic measurements with Ar, Kr and Xe gas at pressures in the range of 1-50 atm as well as some preliminary measurements with liquid Xe and liquid Ar. With the gaseous detectors we succeeded in detecting scintillation light produced by 22 keV X-rays with an efficiency of close to 100%. We also detected the scintillation light produced by bs (5 keV deposit energy) with an efficiency close to 25%. Successful detection of scintillation from 22 keV gammas open new experimental possibilities not only for nTOF and ICARUS experiments, but also in others, like WIMPs search through nuclear recoil emission.

physics.ins-det↗

arXiv2000

Detection of very small neutrino masses in double-beta decay using laser tagging

We describe an approach to the study of neutrino masses that combines quantum optics techniques with radiation detectors to obtain unprecedented sensitivity. With it the search for Majorana neutrino masses down to $\sim$10 meV will become accessible. The experimental technique uses the possibility of individually detecting $\rm Ba^+$-ions in the final state of $\rm ^{136}Xe$ double-beta decay via resonant excitation with a set of lasers aimed at a specific location in a large Time Projection Chamber. The specificity of the atomic levels provides tagging and, together with more traditional event recognition parameters, greatly suppresses radioactive backgrounds.

hep-ex↗

arXiv1999

Measurement of neutrino oscillations by means of a high density detector on the atmospheric neutrino beam

A high-density calorimeter, consisting of magnetized iron planes interleaved by RPCs, as tracking and timing devices, is a good candidate for a next generation experiment on atmospheric neutrinos. With 34 kt of mass and in four years of data taking, this experiment will be sensitive to $ν_μ\to ν_x$ oscillation with $Δm^2 > 6 \times 10^{-5}$ and mixing near to maximal and fully cover the region of oscillation parameters suggested by Super-Kamiokande results. Moreover, the experimental method will enable to measure the oscillation parameters from the modulation of the L/E spectrum ($ν_μ$ disappearance). For $Δm^2 > 3 \times 10^{-3}$ eV$^2$, this experiment can also establish whether the oscillation occurs into a tau or a sterile neutrino, by looking for an excess of muon-less events at high energies produced by upward-going tau neutrinos ($ν_τ$ appearance).

hep-ex↗

arXiv1998

Physics Projects for a Future CERN-LNGS Neutrino Programme

We present an overview of the future projects concerning the neutrino oscillation physics in Europe. Recently a joint CERN-LNGS scientific committee has reviewed several proposals both for the study of atmospheric neutrinos and for long (LBL) and short baseline (SBL) neutrino oscillation experiments. The committee has indicated the priority that the European high energy physics community should follows in the field of neutrino physics, namely a new massive, atmospheric neutrino detector and a nu_tau appearance campaign exploiting the new CERN-LNGS Neutrino Facility (NGS), freshly approved by CERN and INFN. The sensitivity and the discovery potential of the whole experimental program in the Super-Kamiokande allowed region are discussed.

hep-ph↗

arXiv1998

Measurement of Atmospheric Neutrino Oscillations with a High-Density Detector

We propose an experiment to test the hypothesis that the reported anomaly on atmospheric neutrino fluxes is due to nu_mu <-> nu_x oscillations. It will rely both on a disappearance technique, exploiting the method of the dependence of the event rate on L/E, which was recently shown to be effective for detection of neutrino oscillation and measurement of the oscillation parameters, and on an appearance technique, looking for an excess of muon-less events at high energy produced by upward-going tau neutrinos. The detector will consist of iron planes interleaved by limited streamer tubes. The total mass will be about 30 kt. The possibility of recuperating most of the instrumentation from existing detectors allows to avoid R&D phases and to reduce construction time. In four years of data taking, this experiment will be sensitive to oscillations nu_mu <-> nu_x with Delta m^2 > 10^-4 eV^2 and a mixing near to maximal, and answer the question whether nu_x is a sterile or a tau neutrino.

hep-ph↗

arXiv1998

A Test of $\numunux$ Oscillations and determination of the $Δm^2$ parameter of Atmospheric Neutrinos using the $L/E$ method

We point out that the measurement of the $L/E$ distribution of atmospheric neutrino events with sufficient resolution in order to observe the characteristic modulations of neutrino oscillations would provide a unique way to test the $\numunux$ oscillations nature of the atmospheric neutrino anomaly in the parameter range $5\times 10^{-4} < Δm^2 < 2\times 10^{-3}\rm\ eV^2$. With an integrated exposure of a few tens of kiloton-year, this method can cover the lower part of the $Δm^2$ region of the currently allowed atmospheric neutrino solution and is therefore complementary to the one explorable with planned long-baseline neutrino beam experiments. We stress that experimentally this method relies on the ability to measure high energy muons ($E_μ>5\rm GeV$). A large magnetized calorimeter of several kilotons would be ideally suited for this measurement. The existing LEP detectors augmented with atmospheric neutrino triggers could also be used to perform such a study.

hep-ph↗