A high harmonic gyrotron with an axis-encircling electron beam and a permanent magnet

A gyrotron with an axis-encircling electron beam is capable of high-frequency operation, because the high-beam efficiency is kept even at high harmonics of the electron cyclotron frequency. We have designed and constructed such a gyrotron with a permanent magnet. The gyrotron has already operated successfully at the third, fourth, and fifth harmonics. The frequencies are 89.3, 112.7, and 138 GHz, respectively, and the corresponding cavity modes are TE/sub 311/, TE/sub 411/, and TE/sub 511/. The permanent magnet system is quite novel and consists of many magnet elements made of NbFeB and additional coils for controlling the field intensities in the cavity and electron gun regions. The magnetic field in the cavity region can be varied from 0.97 to 1.18 T. At the magnetic field intensities, the output powers at the third and the fourth harmonics are 1.7 and 0.5 kW, respectively. The gyrotron is pulsed, the pulse length is 1 ms and the repetition frequency is 1 Hz. The beam energy is 40 kV and the beam current is 1.2-1.3 A. Beam efficiencies and emission patterns have also been measured. In this paper, the experimental results of the gyrotron are described and compared with computer simulations

First Data Release of the Hyper Suprime-Cam Subaru Strategic Program

The Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP) is a three-layered imaging survey aimed at addressing some of the most outstanding questions in astronomy today, including the nature of dark matter and dark energy. The survey has been awarded 300 nights of observing time at the Subaru Telescope and it started in March 2014. This paper presents the first public data release of HSC-SSP. This release includes data taken in the first 1.7 years of observations (61.5 nights) and each of the Wide, Deep, and UltraDeep layers covers about 108, 26, and 4 square degrees down to depths of i~26.4, ~26.5, and ~27.0 mag, respectively (5sigma for point sources). All the layers are observed in five broad bands (grizy), and the Deep and UltraDeep layers are observed in narrow bands as well. We achieve an impressive image quality of 0.6 arcsec in the i-band in the Wide layer. We show that we achieve 1-2 per cent PSF photometry (rms) both internally and externally (against Pan-STARRS1), and ~10 mas and 40 mas internal and external astrometric accuracy, respectively. Both the calibrated images and catalogs are made available to the community through dedicated user interfaces and database servers. In addition to the pipeline products, we also provide value-added products such as photometric redshifts and a collection of public spectroscopic redshifts. Detailed descriptions of all the data can be found online. The data release website is https://hsc-release.mtk.nao.ac.jp/.Comment: 34 pages, 20 figures, 7 tables, moderate revision, accepted for publication in PAS

The Hyper Suprime-Cam SSP survey: Overview and survey design

Hyper Suprime-Cam (HSC) is a wide-field imaging camera on the prime focus of the 8.2-m Subaru telescope on the summit of Mauna Kea in Hawaii. A team of scientists from Japan, Taiwan, and Princeton University is using HSC to carry out a 300-night multi-band imaging survey of the high-latitude sky. The survey includes three layers: the Wide layer will cover 1400 deg2 in five broad bands (grizy), with a 5 σ point-source depth of r ≈ 26. The Deep layer covers a total of 26 deg2 in four fields, going roughly a magnitude fainter, while the UltraDeep layer goes almost a magnitude fainter still in two pointings of HSC (a total of 3.5 deg2). Here we describe the instrument, the science goals of the survey, and the survey strategy and data processing. This paper serves as an introduction to a special issue of the Publications of the Astronomical Society of Japan, which includes a large number of technical and scientific papers describing results from the early phases of this survey

PC3-secreted microprotein is expressed in glioblastoma stem-like cells and human glioma tissues

Glioblastoma multiforme (GBM) is the most prevalent malignant primary brain tumor with a high recurrence rate. Despite multimodal therapy including surgical resection, chemotherapy, and radiotherapy, the median survival time after the initial diagnosis of GBM is approximately 14 months. Since cancer stem cells (CSCs) are considered the leading cause of cancer recurrence, glioblastoma stem cell-targeted therapy is a promising strategy for the treatment of GBM. However, because CSC heterogeneity has been implicated in the difficulties of CSC-target therapy, more in-depth knowledge of CSC biology is still required to develop novel therapies. In this study, we established single cell-derived tumorspheres from human glioblastoma U87MG cells. One of these tumorspheres, P4E8 clone, showed CSC-like phenotypes, such as self-renewal capacity, expression of CSC markers, resistance to anti-cancer agents, and in vivo tumorigenicity. Therefore, we used P4E8 cells as a cell-based model of glioblastoma stem cells (GSCs). Gene expression analysis using microarray indicated that the most highly expressed genes in P4E8 cells compared to the parental U87MG were PC3-secreted microprotein (MSMP). Furthermore, MSMP was expressed in patient-derived GSCs and human glioma tissues at the protein level, implying that MSMP might contribute to glioma development and progression

RELIABLE BEAM-INTENSITY CONTROL TECHNIQUE AT THE HIMAC SYNCHROTRON

Short extraction called preliminary extraction has been added before irradiation in order to avoid an overshoot of the beam spill. A fast beam shutter was developed and installed in the extraction line to prevent the beam delivering to the patient during preliminary extraction. The fast shutter enables us to switch from preliminary extraction to irradiation in 100 ms, and the reliability of the beam-intensity control system was drastically improved by the preliminary extraction technique

New technologies for carbon-ion radiotherapy --- Developments at the National Institute of Radiological Sciences, QST, Japan

The National Institute of Radiological Sciences in Japan started clinical studies of carbon-ion radiotherapy (CIRT) in 1994. Due to the high linear energy transfer of highly charged particles, carbon-ion beams show high relative biological effectiveness in cell killing, especially at the Bragg peak of dose near the beam range, which is controlled to conform to a tumor. Recent technological developments for CIRT include fast pencil-beam scanning, fluoroscopic respiratory motion management, advanced beam modeling for treatment planning, and a superconducting rotating gantry, which have contributed to accuracy, precision, and conformation of dose, operational efficiency, and patient comfort. With technological maturity, CIRT facilities are rapidly increasing in Asia and Europe. Ongoing developments include extension to multiple ion species and facility downsizing to raise the quality and availability of ion-beam therapy in medical care

New Nozzle Design and Related Developments for Rotating Gantry at NIRS-HIMAC

Objective: At Heavy Ion Medical Accelerator in Chiba (HIMAC), more than 8000 patients have been successfully treated by carbon ion beams since 1994. The successful results of treatments have led us to construct a new treatment facility equipped with a three-dimensional pencil beam scanning (PBS) irradiation system. After the construction of fixed ports, we start construction of a superconducting rotating gantry. This isocentric rotating gantry can transport heavy ions with the maximum energy of 430 MeV/u, and is capable of performing 3D PBS.Methods: Based on the experience of fixed port, in new nozzle design for the gantry, we focus on the realization of smaller beam size. For this purpose we developed new beam monitors and ripple filters. These new devices are designed to suppress the beam broadening due to multiple scattering. Further, for same reason, the locations of these devices are designed to be closer to the isocenter. The preliminary performance evaluation was performed using the scanning beam from the fixed port.Results: These new design and related beam studies are almost completed. Throughout the beam test, the validity of the design was confirmed.Conclusion: In this presentation, we will report the present status of these new devices and related beam tests.53rd Annual Conference of the Particle Therapy Co-Operative Group (PTCOG53

Performance of multiple-energy operation for scanned carbon-ion therapy at HIMAC

Purpose: For conducting the treatments by scanning irradiation without the use of the energy absorbers, the accelerator system is required to output therapy beams of many different energies. In addition, it is also demanded that the properties, such as spill, position and size, of the beams are reliable for irradiation accuracy.Methods: We have developed a multiple-energy operation method to produce the carbon-ion beams with various energies of more than 200 steps between 56 and 430 MeV/u in a single cycle of the synchrotron. By using this method, the accelerator system can perform a quick change of the output beam energy. To verify that the output beams would meet therapy requirements, we carried out the irradiation experiments at Heavy Ion Medical Accelerator in Chiba (HIMAC).Results: The beam intensity was controlled as required from the irradiation control system, and the beam spill ripple was low in the wide intensity range between 107 and 109 particles per second (pps). The position and size of the beam spot were stable, and their fluctuations were small for all beam energies.Conclusions: The experimental results proved that our system can provide the beams meeting the therapy requirements for all available energies. We will report the performance of our system in our presentation.53rd Annual Conference of the Particle Therapy Co-Operative Group (PTCOG53