Search

The CYGNO project aims at realizing a one cubic meter gaseous Time Projection Chamber (TPC) equipped with Scientific CMOS (sCMOS) commercial cameras to optically readout Gas Electron Multiplier (GEM) to be operated at the underground of Gran Sasso National Laboratory (LNGS). The purpose of the project is to study the technology needed for a large size gaseous TPC (30–100 m 3) operated at atmospheric pressure for the directional search of low mass O(GeV) dark matter and low energy (eg solar) neutrinos astronomy. The roadmap of the project foresees the underground operation of a 50 litres TPC prototype, called LIME, the largest TPC realized with this technology, fully equipped with copper and water shielding. LIME is equivalent to about a 1/20 of the CYGNO demonstrator and aims to validate: The construction materials, the Monte Carlo simulations, the data reconstruction and the particle identification performances at low energy threshold. LIME is under installation at the LNGS and it is supposed to start data taking at the beginning of 2022. The detector description and installation will be presented, as well as the overground performance and limitations that require underground characterization. [ABSTRACT FROM AUTHOR]

The DAΦNE Beam Test Facility (BTF) is a beam transfer line optimized for the production of electron or positron bunches, in a wide range of multiplicities and down to single-electron mode, in the energy range between 50 and 800 MeV. The typical pulse duration is 10 ns and the maximum repetition rate is 50 Hz. The facility design has been optimized for detector calibration purposes. The BTF has been successfully commissioned in February 2002 and started operation in the same year in November. The schemes of operation, the commissioning results, as well as the first users’ experience are reported here. [Copyright &y& Elsevier]

At DAΦNE luminosity measurements are performed by detecting the photons from single Bremsstrahlung at the two interaction points. Set up and measurement method are presented with special emphasis on background subtraction schemes, error evaluation and machine related issues. [Copyright &y& Elsevier]

Large granularity and high sensitivity commercial CMOS readout systems open the possibility of developing particle detectors with very interesting performance for different applications, from the search of rare and exotics events, such as dark matter directional candidates, to high quality neutron/ion/hadron beam monitor, mainly for medical applications. The gas scintillation mechanisms was exploited for starting an R&D on large TPC-based detector, equipped with a Triple GEM amplification stage optically readout. By this approach, a 7 l sensitive volume detector was built and tested. Space resolutions of 35 μ m on the GEM plane (X, Y) and 100 μ m on Z and energy measurements with a precision of about 25% were obtained. Analysis of the track shapes provides precious information allowing very good particle discrimination. [ABSTRACT FROM AUTHOR]

Abstract: A new neutron spectrometer, designed to simultaneously respond from the thermal domain up to hundreds of MeV neutrons, was designed and built in the framework of the INFN project NESCOFI@BTF. It has been called SP2 (SPherical SPectrometer) and it consists of 31 thermal neutron detectors embedded in a 25cm diameter polyethylene sphere with an internal 1cm thick lead shell. The new spectrometer shows similar performance as the Bonner sphere spectrometer, but has the notable advantage of requiring only one exposure to determine the whole spectrum. The SP2 response matrix, previously calculated with MCNP, has been experimentally evaluated with monochromatic reference neutron fields from 147keV to 14.8MeV at PTB Braunschweig. As suitable thermal neutron detectors, Dysprosium activation foils were adopted at this stage. The results of the experiment confirmed the correctness of the response matrix within an overall uncertainty of ±3%. The next phase of the NESCOFI@BTF project will be the replacement of passive detectors with active counters, thus leading to a real-time spectrometric monitor that is expected to significantly innovate the neutron control task in neutron-producing facilities, such as the beam-lines for industrial irradiation or condensed matter studies. [Copyright &y& Elsevier]

Abstract: This communication describes the design specifications for a neutron spectrometer consisting of 31 thermal neutron detectors, namely Dysprosium activation foils, embedded in a 25cm diameter polyethylene sphere which includes a 1cm thick lead shell insert that degrades the energy of neutrons through ( n ,xn ) reactions, thus allowing to extension of the energy range of the response up to hundreds of MeV neutrons. The new spectrometer, called SP2 (SPherical SPectrometer), relies on the same detection mechanism as that of the Bonner Sphere Spectrometer, but with the advantage of determining the whole neutron spectrum in a single exposure. The Monte Carlo transport code MCNPX was used to design the spectrometer in terms of sphere diameter, number and position of the detectors, position and thickness of the lead shell, as well as to obtain the response matrix for the final configuration. This work focuses on evaluating the spectrometric capabilities of the SP2 design by simulating the exposure of SP2 in neutron fields representing different irradiation conditions (test spectra). The simulated SP2 readings were then unfolded with the FRUIT unfolding code, in the absence of detailed pre-information, and the unfolded spectra were compared with the known test spectra. The results are satisfactory and allowed approving the production of a prototypal spectrometer. [Copyright &y& Elsevier]

Abstract: At the core of the AGILE scientific instrument, designed to operate on a satellite, there is the Gamma Ray Imaging Detector (GRID) consisting of a Silicon Tracker (ST), a Cesium Iodide Mini-Calorimeter and an Anti-Coincidence system of plastic scintillator bars. The ST needs an on-ground calibration with a beam to validate the simulation used to calculate the energy response function and the effective area versus the energy and the direction of the rays. A tagged beam line was designed at the Beam Test Facility (BTF) of the INFN Laboratori Nazionali of Frascati (LNF), based on an electron beam generating through bremsstrahlung in a position-sensitive target. The energy is deduced by difference with the post-bremsstrahlung electron energy . The electron energy is measured by a spectrometer consisting of a dipole magnet and an array of position sensitive silicon strip detectors, the Photon Tagging System (PTS). The use of the combined BTF-PTS system as tagged photon beam requires understanding the efficiency of tagging, the probability of fake tagging, the energy resolution and the relation of the PTS hit position versus the energy. This paper describes this study comparing data taken during the AGILE calibration occurred in 2005 with simulation. [Copyright &y& Elsevier]

Abstract: A photo-neutron irradiation facility is going to be established at the Frascati National Laboratories of INFN on the base of the successful results of the n@BTF experiment. The photo-neutron source is obtained by an electron or positron pulsed beam, tuneable in energy, current and in time structure, impinging on an optimized tungsten target located in a polyethylene–lead shielding assembly. The resulting neutron field, through selectable collimated apertures at different angles, is released into a 100m2 irradiation room. The neutron beam, characterized by an evaporation spectrum peaked at about 1MeV, can be used in nuclear physics, material science, calibration of neutron detectors, studies of neutron hardness, ageing and study of single event effect. The intensity of the neutron beam obtainable with 510MeV electrons and its fluence energy distribution at a point of reference in the irradiation room were predicted by Monte Carlo simulations and experimentally determined with a Bonner Sphere Spectrometer (BSS). Due to the large photon contribution and the pulsed time structure of the beam, passive photon-insensitive thermal neutron detectors were used as sensitive elements of the BSS. For this purpose, a set of Dy activation foils was used. This paper presents the numerical simulations and the measurements, and compares their results in terms of both neutron spectrum and total neutron fluence. [Copyright &y& Elsevier]

Abstract: We report new measurements of the acoustic excitation of an Al5056 superconductive bar when hit by an electron beam, in a previously unexplored temperature range, down to 0.35K. These data, analyzed together with previous results of a dedicated experiment obtained for T , show a vibrational response enhanced by a factor with respect to that measured in the normal state. This enhancement explains the anomalous large signals due to cosmic rays previously detected in the NAUTILUS gravitational wave detector. [Copyright &y& Elsevier]

Abstract: The AGILE scientific instrument has been calibrated with a tagged -ray beam at the Beam Test Facility (BTF) of the INFN Laboratori Nazionali di Frascati (LNF). The goal of the calibration was the measure of the Point Spread Function (PSF) as a function of the photon energy and incident angle and the validation of the Monte Carlo (MC) simulation of the silicon tracker operation. The calibration setup is described and some preliminary results are presented. [Copyright &y& Elsevier]

Abstract: Testing the new crab waist collision scheme at the e+e− Frascati accelerator complex requires a fast and accurate measurement of the absolute luminosity, as well as a full characterization of the background conditions. To fulfill these requirements, dedicated detectors have been built by the LUMI Collaboration and operated during the 2008 and 2009 runs, providing valuable inputs for the accelerator team. This article motivates their design, describes their installation in the modified interaction region and presents their performances. Another article in the same issue focuses on the results achieved using these detectors. [ABSTRACT FROM AUTHOR]

Abstract: The crab waist collision scheme has been successfully tested at the e+e− Frascati collider during the 2008–2009 runs: the gain in luminosity is consistent with the predictions while the background remains sustainable. Among the various inputs used by the accelerator team to steer this new machine and improve its performances, key online information, absolute luminosity and background level measurements, has been provided by the LUMI detectors: a Bhabha calorimeter and two gamma bremsstrahlung proportional counters. This paper focuses on the results achieved with this experimental setup, described in details in another article. [ABSTRACT FROM AUTHOR]

Abstract: Since the second half of year 2007, the Frascati - factory DAFNE has been running with an upgraded interaction region in order to test the crabbed waist collision scheme. The aim is to reach a large improvement of the specific luminosity of the accelerator. We describe the various detectors realized to have a reliable and fast absolute luminosity measurement, the on-line analysis in order to get rid of the machine background contribution, and the performances of the system. [Copyright &y& Elsevier]

Abstract: The development of different detectors based on GEM technology, mainly to be used for beam diagnostic, is described. The use of GEM foils for detector construction started in Frascati on 2002 with the R&D for LHCb Muon Chambers placed at small angle. Ever since several triple GEM chambers have been built for different applications. The results obtained in several beam tests have shown high performances: high rate capability (), good time resolution (), good space resolution , and good aging resistance after of integrated charge. Recent developments on readout electronics and power supply for portable detectors are presented. [Copyright &y& Elsevier]

The Time Projection Chamber (TPC) is an ideal candidate to finely study the charged particle ionization in a gaseous medium. Large volume TPCs can be readout with a suitable number of channels offering a complete 3D reconstruction of a charged particle track, that is the sequence of its energy releases in the TPC gas volume. Moreover, He-based TPCs are very promising to study keV energy particles as nuclear recoils, opening the possibility for directional searches of Dark Matter (DM) and the study of Solar Neutrinos (SN). In this paper we report the analysis of the data acquired with a small TPC prototype (named LEMOn) built by the CYGNO collaboration that was exposed to a beam of 450 MeV electrons at the Beam Test Facility of National Laboratories of Frascati. LEMOn is operated with a He-C F 4 mixture at atmospheric pressure and is based on a Gas Electron Multipliers amplification stage that produces visible light collected by the high granularity and very good sensitivity of scientific CMOS camera. This type of readout – in conjunction with a fast light detection – allows a 3D reconstruction of the electrons tracks. The electrons are leaving a trail of clusters of ionizations corresponding to a few keV energy release each. Their study leads to predict a keV energy threshold and 1–10 mm longitudinal and 0.1–0.3 mm transverse position resolution (sigma) for nuclear recoils, very promising for the application of optically read out TPC to DM searches and SN measurements. [ABSTRACT FROM AUTHOR]

The Time Projection method is ideal to track low kinetic energy charged particles, in particular for the study for Dark Matter interactions. With this technique we aim to readout large volumes with a moderate number of channels providing a complete 3D reconstruction of the tracks within the sensitive region. The total released energy and the energy density along the tracks can be both measured allowing for particle identification and to solve the head–tail ambiguity of the track. Moreover, in gas, nuclear recoils induced by a Dark Matter particle scattering can yield tracks long enough for its direction to be inferred. We describe here a prototype TPC with a GEM amplification stage. The readout is based on the detection of the light produced in the GEM with a high granularity sCMOS sensor in conjunction with a photomultiplier. The prototype was exposed to γ and neutron source and to minimum ionizing particles, obtaining very promising results in terms of detection efficiency, energy resolution and particle identification. [ABSTRACT FROM AUTHOR]

The resonant-mass gravitational wave detector NAUTILUS has recently recorded signals due to cosmic rays crossing. Very large signals have been observed in the superconductive state of the antenna. In order to investigate this anomalous response at low temperatures, the Rivelazione Acustica di Particelle experiment has been approved. Its purpose is the measurement of the mechanical vibrations in a superconducting (T∼100 mK) cylindrical aluminium bar when hit by 105 electrons at 510 MeV from the DAΦNE Beam Test Facility, corresponding to the energies released by extensive air showers in the NAUTILUS antenna. The results of this measurement are crucial to understand the interaction of ionizing particles with bulk superconductors and to confirm the results on the thermo-acoustic model of the past experiments. [Copyright &y& Elsevier]

RAP is an experiment aimed to measure the effects caused by high-energy electrons impinging on bulk superconductors. The motivation is the anomalous high-energy cosmic ray rate detected by the gravitational wave antenna NAUTILUS when operated in superconducting regime. [Copyright &y& Elsevier]