22 research outputs found
Spallation Neutron Production by 0.8, 1.2 and 1.6 GeV Protons on various Targets
Spallation neutron production in proton induced reactions on Al, Fe, Zr, W,
Pb and Th targets at 1.2 GeV and on Fe and Pb at 0.8, and 1.6 GeV measured at
the SATURNE accelerator in Saclay is reported. The experimental
double-differential cross-sections are compared with calculations performed
with different intra-nuclear cascade models implemented in high energy
transport codes. The broad angular coverage also allowed the determination of
average neutron multiplicities above 2 MeV. Deficiencies in some of the models
commonly used for applications are pointed out.Comment: 20 pages, 32 figures, revised version, accepted fpr publication in
Phys. Rev.
The acrylic vessel for JSNS-II neutrino target
The JSNS (J-PARC Sterile Neutrino Search at J-PARC Spallation Neutron
Source) is an experiment designed for the search for sterile neutrinos. The
experiment is currently at the stage of the second phase named JSNS-II
with two detectors at near and far locations from the neutrino source. One of
the key components of the experiment is an acrylic vessel, that is used for the
target volume for the detection of the anti-neutrinos. The specifications,
design, and measured properties of the acrylic vessel are described
Spallation reactions. A successful interplay between modeling and applications
The spallation reactions are a type of nuclear reaction which occur in space
by interaction of the cosmic rays with interstellar bodies. The first
spallation reactions induced with an accelerator took place in 1947 at the
Berkeley cyclotron (University of California) with 200 MeV deuterons and 400
MeV alpha beams. They highlighted the multiple emission of neutrons and charged
particles and the production of a large number of residual nuclei far different
from the target nuclei. The same year R. Serber describes the reaction in two
steps: a first and fast one with high-energy particle emission leading to an
excited remnant nucleus, and a second one, much slower, the de-excitation of
the remnant. In 2010 IAEA organized a worskhop to present the results of the
most widely used spallation codes within a benchmark of spallation models. If
one of the goals was to understand the deficiencies, if any, in each code, one
remarkable outcome points out the overall high-quality level of some models and
so the great improvements achieved since Serber. Particle transport codes can
then rely on such spallation models to treat the reactions between a light
particle and an atomic nucleus with energies spanning from few tens of MeV up
to some GeV. An overview of the spallation reactions modeling is presented in
order to point out the incomparable contribution of models based on basic
physics to numerous applications where such reactions occur. Validations or
benchmarks, which are necessary steps in the improvement process, are also
addressed, as well as the potential future domains of development. Spallation
reactions modeling is a representative case of continuous studies aiming at
understanding a reaction mechanism and which end up in a powerful tool.Comment: 59 pages, 54 figures, Revie
Characterization of the correlated background for a sterile neutrino search using the first dataset of the JSNS experiment
JSNS (J-PARC Sterile Neutrino Search at J-PARC Spallation Neutron Source)
is an experiment that is searching for sterile neutrinos via the observation of
appearance oscillations using muon
decay-at-rest neutrinos. Before dedicated data taking in the first-half of
2021, we performed a commissioning run for 10 days in June 2020. Using the data
obtained in this commissioning run, in this paper, we present an estimate of
the correlated background which imitates the signal in a
sterile neutrino search. In addition, in order to demonstrate future prospects
of the JSNS experiment, possible pulse shape discrimination improvements
towards reducing cosmic ray induced fast neutron background are described.Comment: 7 pages, 3 figure
A feasibility study of H sup - beam extraction technique using YAG laser
Under a framework of JAERI-KEK joint project of high intensity proton accelerator, as for research and develop of the accelerator driven nuclear transmutation of the long lived radioactive nuclide, it is planed to built the Transmutation Physics Experiment Facility (TEF-P) and the Transmutation Engineering Experiment Facility (TEF-E). The TEF-P is used for the experiments for subcritical system coupled with a spallation neutron target bombarded with 600-MeV proton beam accelerated by the LINAC. To limit the maximum thermal power less than 500 W at the TEF-P, an incident beam power should be less than 10 W. On the contrary, at the TEF-E, high power beam of 200 kW is requested. Both high and low power beams are demanded for the transmutation facilities. It is difficult to deliver a low power beam to the TEF-P. Conventional beam extraction technique with a thin foil, is not desirable because the scattering of the beam at the foil requires the massive shield. Therefore, we study a new technique to extract a small portion of the beam precisely from the high intensity beam by using a laser beam. By a laser beam, H sup - in the beam from LINAC is partially changed to H sup 0 beam so that a low current H sup 0 beam can be obtained. As the cross section of the charge exchange reaction for H sup - ions has a peak around at a wave length of 1 mu m for photons, YAG laser is suitable for this charge exchange because of its 1.06 mu m wave length. It is derived that 10 W beam for 600-MeV proton can be extracted by the YAG laser with power of 2 J for each pulse of 25 Hz. By this technique, the pulse width for the extracted beam can be controlled by changing the time width of laser irradiation. When a charge exchanger having the beam collide point existing in straight section, a background beam current of projectile, however, will be increased due to the interaction with the residual gas in the beam duct. Thus, a charge exchanger is devised having the beam collide point in a by changing this charge exchanger, it is demonstrated that the possibility of the charge exchange due to interactions with residual gas can be drastically decrease. By the above studies, it is recognized that feasibility of the technique of beam extraction with the laser