42 research outputs found
Multigap RPC time resolution to 511 keV annihilation photons
The time resolution of Multigap Resistive Plate Counters (MRPCs) to keV
gamma rays has been investigated using a Na source and four detectors.
The MRPCs time resolution has been derived from the Time-of-Flight information,
measured from pairs of space correlated triggered events. A GEANT4 simulation
has been performed to analyze possible setup contributions and to support
experimental results. A time resolution (FWHM) of ps and ps has
been measured for a single MRPC with four m gas gaps by considering
respectively one and two independent pairs of detectors.Comment: 25 pages, 14 figure
Time of flight detectors with SiPMT array readout
none6noTime-of-flight detectors, based on scintillation counters, may use conventional photomultipliers for the readout. Problems arise in presence of external magnetic fields. SiPMT arrays are insensitive to magnetic fields and may be a suitable option to replace photomultipliers. Timing performances for several types of SiPMT arrays have been studied and results are presented.Bonesini, M; Bertoni, R.; de Bari, A.; Nardò, R.; Prata, M.; Rossella, M.Bonesini, M; Bertoni, R.; DE BARI, Antonio; Nardo', Roberto; Prata, M.; Rossella, M
Development and commissioning of the Timing Counter for the MEG Experiment
The Timing Counter of the MEG (Mu to Electron Gamma) experiment is designed
to deliver trigger information and to accurately measure the timing of the
in searching for the decay . It is part of a
magnetic spectrometer with the decay target in the center. It consists
of two sectors upstream and downstream the target, each one with two layers:
the inner one made with scintillating fibers read out by APDs for trigger and
track reconstruction, the outer one consisting in scintillating bars read out
by PMTs for trigger and time measurement. The design criteria, the obtained
performances and the commissioning of the detector are presented herein.Comment: 10 pages, 20 figures. Presented at the IEEE Nuclear Science Symposium
2010, Knoxville, TN, USA. Accepted by IEEE Transaction on Nuclear Scienc
Steps towards the hyperfine splitting measurement of the muonic hydrogen ground state: pulsed muon beam and detection system characterization
The high precision measurement of the hyperfine splitting of the
muonic-hydrogen atom ground state with pulsed and intense muon beam requires
careful technological choices both in the construction of a gas target and of
the detectors. In June 2014, the pressurized gas target of the FAMU experiment
was exposed to the low energy pulsed muon beam at the RIKEN RAL muon facility.
The objectives of the test were the characterization of the target, the
hodoscope and the X-ray detectors. The apparatus consisted of a beam hodoscope
and X-rays detectors made with high purity Germanium and Lanthanum Bromide
crystals. In this paper the experimental setup is described and the results of
the detector characterization are presented.Comment: 22 pages, 14 figures, published and open access on JINS
MEG Upgrade Proposal
We propose the continuation of the MEG experiment to search for the charged
lepton flavour violating decay (cLFV) \mu \to e \gamma, based on an upgrade of
the experiment, which aims for a sensitivity enhancement of one order of
magnitude compared to the final MEG result, down to the
level. The key features of this new MEG upgrade are an increased rate
capability of all detectors to enable running at the intensity frontier and
improved energy, angular and timing resolutions, for both the positron and
photon arms of the detector. On the positron-side a new low-mass, single
volume, high granularity tracker is envisaged, in combination with a new highly
segmented, fast timing counter array, to track positron from a thinner stopping
target. The photon-arm, with the largest liquid xenon (LXe) detector in the
world, totalling 900 l, will also be improved by increasing the granularity at
the incident face, by replacing the current photomultiplier tubes (PMTs) with a
larger number of smaller photosensors and optimizing the photosensor layout
also on the lateral faces. A new DAQ scheme involving the implementation of a
new combined readout board capable of integrating the diverse functions of
digitization, trigger capability and splitter functionality into one condensed
unit, is also under development. We describe here the status of the MEG
experiment, the scientific merits of the upgrade and the experimental methods
we plan to use.Comment: A. M. Baldini and T. Mori Spokespersons. Research proposal submitted
to the Paul Scherrer Institute Research Committee for Particle Physics at the
Ring Cyclotron. 131 Page
Experimental results on RPC neutron sensitivity
Abstract RPC neutron sensitivity has been studied during two tests done with different neutrons energies. In the first test, neutrons from spontaneous fission events of 252 Cf were used (average energy 2 MeV ); while in the second test neutrons were produced using a 50 MeV deuteron beam on a 1 cm thick beryllium target (average energy 20 MeV ). Preliminary results show that the neutron sensitivity in double gap mode is (0.52±0.03)×10−3 at about 2 MeV and (5.3±0.5)×10−3 at about 20 MeV
FAMU: study of the energy dependent transfer rate \u39b \u3bcp \u2192 \u3bcO
The main goal of the FAMU experiment is the measurement of the hyperfine splitting (hfs) in the 1S state of muonic hydrogen \u394Ehfs (\u3bc - p)1S. The physical process behind this experiment is the following: \u3bcp are formed in a mixture of hydrogen and a higher-Z gas. When absorbing a photon at resonance-energy \u394Ehfs 48 0.182 eV, in subsequent collisions with the surrounding H 2 molecules, the \u3bcp is quickly de-excited and accelerated by ~ 2/3 of the excitation energy. The observable is the time distribution of the K-lines X-rays emitted from the \u3bcZ formed by muon transfer (\u3bcp) + Z \u2192 (\u3bcZ)* + p, a reaction whose rate depends on the \u3bcp kinetic energy. The maximal response, to the tuned laser wavelength, of the time distribution of X-ray from K-lines of the (\u3bcZ)* cascade indicate the resonance. During the preparatory phase of the FAMU experiment, several measurements have been performed both to validate the methodology and to prepare the best configuration of target and detectors for the spectroscopic measurement. We present here the crucial study of the energy dependence of the transfer rate from muonic hydrogen to oxygen (\u39b \u3bcp \u2192 \u3bc0 ), precisely measured for the first time
A limit for the mu -> e gamma decay from the MEG experiment
A search for the decay mu -> e gamma, performed at PSI and based on data from
the initial three months of operation of the MEG experiment, yields an upper
limit on the branching ratio of BR(mu -> e gamma) < 2.8 x 10**-11 (90% C.L.).
This corresponds to the measurement of positrons and photons from ~ 10**14
stopped mu-decays by means of a superconducting positron spectrometer and a 900
litre liquid xenon photon detector.Comment: 13 pages, 9 figures. v2: improved estimate of photon reconstruction
efficienc