98 research outputs found
A new technique for direct investigation of dark matter
The MOSCAB experiment (Materia OSCura A Bolle) uses a new technique for Dark
Matter search. The Geyser technique is applied to the construction of a
prototype detector with a mass of 0.5 kg and the encouraging results are
reported here; an accent is placed on a big detector of 40 kg in construction
at the Milano-Bicocca University and INFN
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
First measurement of the temperature dependence of muon transfer rate from muonic hydrogen atoms to oxygen
We report the first measurement of the temperature dependence of muon transfer rate from muonic hydrogen atoms to oxygen between 100 and 300 K. Data were obtained from the X-ray spectra of delayed events in a gaseous target, made of a H2/O2 mixture, exposed to a muon beam. This work sets constraints on theoretical models of muon transfer and is of fundamental importance for the measurement of the hyperfine splitting of muonic hydrogen ground state as proposed by the FAMU collaboration
First measurement of the temperature dependence of muon transfer rate from muonic hydrogen atoms to oxygen
We report the first measurement of the temperature dependence of muon transfer rate from muonic hydrogen atoms to oxygen between 100 and 300 K. Data were obtained from the X-ray spectra of delayed events in a gaseous target, made of a H2/O2 mixture, exposed to a muon beam. This work sets constraints on theoretical models of muon transfer and is of fundamental importance for the measurement of the hyperfine splitting of muonic hydrogen ground state as proposed by the FAMU collaboration
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
First FAMU observation of muon transfer from \u3bcp atoms to higher-Z elements
Abstract: The FAMU experiment aims to accurately measure the hyperfine splitting of the ground
state of the muonic hydrogen atom. A measurement of the transfer rate of muons from hydrogen
to heavier gases is necessary for this purpose. In June 2014, within a preliminary experiment, a
pressurized gas-target was exposed to the pulsed low-energy muon beam at the RIKEN RAL muon
facility (Rutherford Appleton Laboratory, U.K.). The main goal of the test was the characterization
of both the noise induced by the pulsed beam and the X-ray detectors. The apparatus, to some
extent rudimental, has served admirably to this task. Technical results have been published that
prove the validity of the choices made and pave the way for the next steps. This paper presents the
results of physical relevance of measurements of the muon transfer rate to carbon dioxide, oxygen,
and argon from non-thermalized excited \u3bcp atoms. The analysis methodology and the approach
to the systematics errors are useful for the subsequent study of the transfer rate as function of the
kinetic energy of the \u3bcp currently under way
The FAMU experiment at RIKEN-RAL to study the muon transfer rate from hydrogen to other gases
The aim of the FAMU (Fisica degli Atomi Muonici) experiment is to realize the first
measurement of the hyperfine splitting (hfs) in the 1S state of muonic hydrogen _Ehf s
1S , by using the
RIKEN-RAL intense pulsed muon beam and a high-energy mid-infrared tunable laser. This requires
a detailed study of the muon transfer mechanism at different temperatures and hence at different
epithermal states of the muonic system. The experimental setup involves a cryogenic pressurized
gas target and a detection system based on silicon photomultipliers-fiber beam hodoscopes and high
purity Germanium detectors and Cerium doped Lanthanium Bromide crystals, for X-rays detection
at energies around 100 keV.
Simulation, construction and detector performances of the FAMU apparatus at RAL are reported
in this paper
The FAMU experiment at RIKEN-RAL to study the muon transfer rate from hydrogen to other gases
The aim of the FAMU (Fisica degli Atomi Muonici) experiment is to realize the first
measurement of the hyperfine splitting (hfs) in the 1S state of muonic hydrogen _Ehf s
1S , by using the
RIKEN-RAL intense pulsed muon beam and a high-energy mid-infrared tunable laser. This requires
a detailed study of the muon transfer mechanism at different temperatures and hence at different
epithermal states of the muonic system. The experimental setup involves a cryogenic pressurized
gas target and a detection system based on silicon photomultipliers-fiber beam hodoscopes and high
purity Germanium detectors and Cerium doped Lanthanium Bromide crystals, for X-rays detection
at energies around 100 keV.
Simulation, construction and detector performances of the FAMU apparatus at RAL are reported
in this paper
The small angle tile calorimeter in the DELPHI experiment
The {\bf S}mall angle {\bf TI}le {\bf C}alorimeter ({\bf STIC}) provides calorimetric coverage in the very forward region of the DELPHI experiment at the CERN LEP collider. The structure of the calorimeters, built with a so-called ``shashlik'' technique, gives a perfectly hermetic calorimeter and still allows for the insertion of tracking detectors within the sampling structure to measure the direction of the showering particle. A charged-particle veto system, composed of two scintillator layers, makes it possible to trigger on single photon events and provides e- separat ion. Results are presented from the extensive studies of these detectors in the CERN testbeams prior to installation and of the detector performance at LEP
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