12 research outputs found
Development of fast-response PPAC with strip-readout for heavy-ion beams
A strip-readout parallel-plate avalanche counter (SR-PPAC) has been developed
aiming at the high detection efficiency and good position resolution in
high-intensity heavy-ion measurements. The performance was evaluated using 115
MeV/u Xe, 300 MeV/u Sn, and 300 MeV/u Ca beams. A
detection efficiency beyond 99% for these beams is achieved even at an incident
beam intensity of 0.7 billion particles per second. The best position
resolution achieved is 235 um (FWHM).Comment: 16 pages, 18 figures, 2 table
Investigating nuclear shell structure in the vicinity of 78Ni: Low-lying excited states in the neutron-rich isotopes 80,82Zn
L
陽子弾性散乱による[204],[206],[208]Pbの中性子密度分布の抽出
京都大学0048新制・課程博士博士(理学)甲第15867号理博第3608号新制||理||1526(附属図書館)28446京都大学大学院理学研究科物理学・宇宙物理学専攻(主査)教授 永江 知文, 教授 中家 剛, 准教授 川畑 貴裕学位規則第4条第1項該当Doctor of ScienceKyoto UniversityDA
Study of Multi-neutron Systems with SAMURAI Spectrometer
The tetraneutron has been drawing the attention of the nuclear physics community for decades, but a firm conclusion on its existence and properties is still far from being reached despite many experimental and theoretical efforts. New measurements have recently been performed at RIBF with the SAMURAI spectrometer by applying complementary reaction probes, which will help to pin down the properties of this four-neutron system
Performance of prototype Dual Gain Multilayer Thick GEM with high-intensity heavy-ion beam injections in low-pressure hydrogen gas
A prototype Dual Gain Multilayer Thick Gas Electron Multilyer (DG-M-THGEM)
with an active area of 10 cm 10 cm was manufactured aiming at the
production of a large-volume active-target time projection chamber which can
work under the condition of high-intensity heavy-ion beam injections. The
DG-M-THGEM has a alternating structure of electrodes and insulators. Effective
gas gains of two regions, which are called beam and recoil regions, are
separately controlled. Performance of the prototype DG-M-THGEM in hydrogen gas
at a pressure of 40 kPa was evaluated. Irradiating a Xe beam, an
effective gas gain lower than 100 with a charge resolution of 3% was achieved
in the beam region while the effective gas gain of 2000 was maintained in the
recoil region. Position distributions of measured charges along the beam axis
were investigated in order to evaluate gain uniformity in the high intensity
beam injection. The gain shift was estimated by simulations considering space
charges in the drift region. The gain shift was suppressed within 3% even at
the beam intensity of 2.5 10 particles per second.Comment: 19 pages, 14 figures, 3 table
-clustering in Heavy Nuclei Sn Probed with Reaction
International audienceWe measured the α-clustering strength at the surface of tin isotopes ^112,116,120,124Sn by using quasi-free reaction at RCNP. Formation of α clusters at the surface of tin isotopes was clearly evidenced from our results. Surface α-clustering in heavy nuclei provides a natural explanation for the origin of α particles in α decay, and may also impact the neutron-skin thickness which plays a critical role in constraining the nuclear symmetry energy
-clustering at the Surface of Tin Isotopes Sn Studied with Reaction
International audienceα-clustering strength at the surface of tin isotopes ^112,116,120,124Sn was measured by using quasi-free (p, pα) reaction at RCNP. By measuring the scattered protons and α particles in coincidence, formation of α clusters at the surface of tin isotopes was clearly evidenced. Surface α-clustering in heavy nuclei provides a natural explanation for the origin of α particles in α decay, and may also impact the neutron-skin thickness which plays an important role in constraining the nuclear symmetry energy
Formation of α clusters in dilute neutron-rich matter
International audienceThe surface of neutron-rich heavy nuclei, with a neutron skin created by excess neutrons, provides an important terrestrial model system to study dilute neutron-rich matter. By using quasi-free α cluster–knockout reactions, we obtained direct experimental evidence for the formation of α clusters at the surface of neutron-rich tin isotopes. The observed monotonous decrease of the reaction cross sections with increasing mass number, in excellent agreement with the theoretical prediction, implies a tight interplay between α-cluster formation and the neutron skin. This result, in turn, calls for a revision of the correlation between the neutron-skin thickness and the density dependence of the symmetry energy, which is essential for understanding neutron stars. Our result also provides a natural explanation for the origin of α particles in α decay.</jats:p