Report on the geomorphological, paleomagnetic, geodetic, zoological and botanical field work in the Sør Rondane Mountains, 1988-89 summer season (JARE-30)

The summer party of the 30th Japanese Antarctic Research Expedition (JARE-30) carried out the geomorphological, paleomagnetic, geodetic, zoological and botanical field work in the western part of the Sør Rondane Mountains for 35 days from December 29,1988 to February 1,1989,and around Asuka Station for 8 days from February 2 to 9,1989. The field work in February was largely hampered by bad weather including blizzard. In addition to earth scientists who have been in charge of the field operation of the Sør Rondane Mountains since JARE-26 (1985), biologists joined the field party for the first time this season under the similar planning and operating scheme formerly adopted. This is the report describing the results of field operations including logistics, a summary of the field work, and some information on weather and surface conditions of snow and ice around the Mountains during this period

セールロンダーネ サンチ チガク セイブツ チョウサ タイ ホウコク 1988-89 (JARE-30)

第30次南極地域観測隊(JARE-30)夏隊のセールロンダーネ山地地学・生物学調査は, 1988年12月29日から1989年2月1日にかけて山地西部で, 2月2日から9日にかけてあすか観測拠点をベースに付近の小山塊で実施された。2月になってからの調査活動は, ブリザード等の強風と地吹雪で効率的でなかった。JARE-26-29の地学調査に生物班が初めて加わったが, 調査計画の立案や行動形態に特に従来と変わったところはない。ここでは, 設営面を含む行動の概要と調査の概略, 調査期間の山地近辺の気象と雪氷状況を報告する。調査の成果については別途, 各分野で詳しく報告される。The summer party of the 30th Japanese Antarctic Research Expedition (JARE-30) carried out the geomorphological, paleomagnetic, geodetic, zoological and botanical field work in the western part of the Sør Rondane Mountains for 35 days from December 29,1988 to February 1,1989,and around Asuka Station for 8 days from February 2 to 9,1989. The field work in February was largely hampered by bad weather including blizzard. In addition to earth scientists who have been in charge of the field operation of the Sør Rondane Mountains since JARE-26 (1985), biologists joined the field party for the first time this season under the similar planning and operating scheme formerly adopted. This is the report describing the results of field operations including logistics, a summary of the field work, and some information on weather and surface conditions of snow and ice around the Mountains during this period

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 $\times$ 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 $^{132}$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 $\times$ 10$^{6}$ particles per second.Comment: 19 pages, 14 figures, 3 table

Exclusive quasi-free proton knockout from oxygen isotopes at intermediate energies

The dependence of the single-particle strength on the difference between proton and neutron separation energies is studied for oxygen isotopes in a wide range of isospins. The cross sections of the quasi-free (p, 2p) reaction on 14,16,18,22,24O were measured at intermediate energies. The measured cross sections are compared to predictions based on the distortedwave impulse approximation and shell-model psd valence-space spectroscopic factors. The reduction factors, which are the ratio of the experimental cross sections to the theoretical predictions, show no apparent dependence on the proton–neutron separation energy difference. The result is compatible with the result of the (e, e p) reaction on stable targets and with the predictions of recent ab initio calculations

Exclusive quasi-free proton knockout from oxygen isotopes at intermediate energies

International audienceThe dependence of the single-particle strength on the difference between proton and neutron separation energies is studied for oxygen isotopes in a wide range of isospins. The cross sections of the quasi-free (p, 2p) reaction on 14,16,18,22,24O were measured at intermediate energies. The measured cross sections are compared to predictions based on the distorted wave impulse approximation and shell-model psd valence-space spectroscopic factors. The reduction factors, which are the ratio of the experimental cross sections to the theoretical predictions, show no apparent dependence on the proton–neutron separation energy difference. The result is compatible with the result of the (e, e p) reaction on stable targets and with the predictions of recent ab initio calculations