G. Giannini

Direct photon production from pions and protons at 200 GeV/c

Direct photon production has been studied by an experiment performed with the NA3 spectrometer at CERN, using incident negative and positive beams at 200 GeV/c interacting with an isoscalar Carbon target. Two different triggers have been used; one of them requires the photon conversion. The experiment is sensitive to direct photons produced with 3.0≦PT≦6 GeV/c and center-of-mass rapidity −0.4≦y*≦1.2. Inclusive cross sections are given for incident π± and protons, and compared with second order QCD predictions; finally an estimation of the gluon structure function of the nucleon is given.

Underground cosmic ray measurement for morphological reconstruction of the 'Grotta Gigante' natural cave.

Abstract Measurement of the muon flux as a function of direction inside the Grotta Gigante natural cave near Trieste (Italy) was carried out using a tracking apparatus. The measured flux, depending in a well established way on the zenith angle and the rock mass crossed by the muons, allowed the determination of the shape of the cave vault which could be compared with that known from topography and related to the available microgravimetric data of the area.

Mass and lifetime limits on new long-lived particles in 300 GeV/c π− interactions

A sensitive search has been done for the production of new long-lived and penetrating particles by 300 GeV/c negative pions. No new state —decaying into at least two charged known particles —has been detected with mass above 1 GeV/c2 and lifetime in the range 5·10−11 s to 5·10−7s. We give upper limits on production cross sections, and consequences on the existence of heavy “axion-like” particles, heavy neutrinos and supersymmetric particles. In particular, this experiment excludes the existence of light gluinos with lifetime in the range 5·10−11 to 10−8s: this closes the last “window of opportunity” for gluinos withM<2 GeV/c2 and lifetime measurable in particle physics experiments.

Direct photon pair production from pions and protons at 200 GeV/c

Direct photon production has been studied by an experiment performed with the NA3 spectrometer at CERN, using incident negative and positive beams at 200 GeV/c interacting with an isoscalar Carbon target. Two different triggers have been used; one of them requires the photon conversion. The experiment is sensitive to direct photons produced with 3.0≦PT≦6 GeV/c and center-of-mass rapidity −0.4≦y*≦1.2. Inclusive cross sections are given for incident π± and protons, and compared with second order QCD predictions; finally an estimation of the gluon structure function of the nucleon is given.

The use of the reaction 9Be(α, γn)12C to determine the energy scale and the efficiency at low energies of stellar collapse neutrino detectors

Abstract Experiments for the detection of gravitational stellar collapse ν e -events are most frequently based on the reaction: ν e + p → n + e + , followed by delayed neutron capture in hydrogen n + p → γ + d, E γ = 2.2 MeV. Data obtained by a low intensity Am/Be source (as n and γ-ray emitter), in association with MACRO scintillation counters, are being used to determine the capability of detecting delayed neutron capture from cascade n, γ-ray emissions. The 9 Be( α , γ n) 12 C reaction is a valuable tool for setting the optimum “stellar gravitational collapse trigger” working conditions both for the detection of the primary ν e -events and for the detection of the delayed neutron captures. The use of the Am/Be source allowed several experimental checks of Monte Carlo calculated detection efficiencies.

Inclusive highP T π0 production from π± and protons at 200 GeV/c

We have measured the inclusive cross-section for π0 production at large transverse momentum by 200 GeV/c positive and negative hadron beams on Carbon targets (2.9<PT<6 GeV/c; −0.4<y*<1.2). We used the NA3 spectrometer at the CERNSPS.

Measurement of punch-through particle fluxes from a 200 cm long beam dump hit by a 300 gev/c pion beam

Abstract We present a measurement of the particle flux punching through tungsten and iron beam dumps; the NA3 spectrometer was used. Momentum spectra and spatial distributions were determined for pions above GeV/ c and for strange particles (K ± , K s 0 , Λ , Ξ ; 15 p c ). Information on the effective attenuation length for strange particles was obtained by comparing the results from dumps of different lengths (200 and 220 cm).

Frontend and readout electronics of the MICE Electron Muon Ranger detector

The MICE experiment is being commissioned at RAL to study the feasibility of a Neutrino Factory: muons are cooled by a dedicated system based on radiofrequency while the particle ID is performed by a KLOE-light detector followed by EMR (Electron Muon Ranger), a fully active tracker-calorimeter positioned at the end of the beamline. EMR consists of 48 planes of 59 1.1 m long scintillator bars with a triangular section. The light in each bar is collected by one 1.2 mm WLS fiber and is readout by a single PMT (Philips XP2972) on one side to provide the information on the charge deposit in the plane and a 64 channel multianode PMT (Hamamatsu) on the other one to digitize the trigger output of each single bar. The single PMT is readout by a CAEN V1731 Waveform Digitizer, while the frontend electronics to treat the multianode signals is organized in two near-detector boards: a FEB (FrontEnd Board) and a buffer board. The FEB hosts a dedicated socket for the MAPMT, the frontend ASIC and two control FPGAs (Altera CYCLONE II) while the buffer board stores the data during the spill. The PMT is connected to the FEB through a flexible multilayer kapton cable. The 64 MAPMT signals are pre-amplified, shaped and discriminated by the MAROC-2 (Omega, LAL), a low noise single power rail ASIC with multiplexed analog and parallel digital outputs. The experiment foresees one event every 5 µs during a spill of 1 ms every 1 s. The 64 discriminated signals are sampled with a 400 MHz clock and in presence of the experiment trigger, the above threshold bars numbers are stored together with a timestamp in the buffer board to be sent to the VME DAQ system during the interspill. The communication is based on the TLK1501 Gigabit link: 6 buffer boards are daisy chained for a total of 8 VME control boards. A configuration board completes the DAQ and is responsible of the configuration of the frontend and of the distribution of the trigger and synchronization clock signals. This paper presents the tests of the electronics and its performance both with a small EMR prototype with square bars and in the test system for the mass production of the final modules.