AIR-COOLED MAGNETIC ALLOY CAVITY FOR J-PARC DOUBLED REP.-RATE SCENARIO

Abstract The upgrade project of the J-PARC MR (Main Ring) based on doubled repetition-rate scenario is in progress to deliver the beam power of 750 kW. The present RF section will be occupied by 9 sets of new magnetic alloy, FT3L, cavities using the direct water cooling scheme. The direct water cooling is the efficient scheme to cool the magnetic alloy core although it requires dedicated high-quality cooling water which does not contain copper oxide and copper ions because copper ions may cause the severe corrosion damage on the magnetic alloy cores. These cavities will be used for the fundamental RF for acceleration which requires high duty operation. The second harmonic RF is necessary to increase the bunch length. This allows to enlarge the beam current because it relaxes the space charge effects during the injection. Thanks to the high impedance FT3L and low duty operation of the second harmonic RF, the power loss in the second harmonic RF system becomes moderate. The air cooled cavity is designed to fit in any locations in the MR where the dedicated high-quality water is not available. This paper reports the design of the second RF system, technical issues to produce the magnetic alloy cores to fit the air cooling, and construction of the system

PERFORMANCE OF MULTI-HARMONIC RF FEEDFORWARD SYSTEM FOR BEAM LOADING COMPENSATION IN THE J-PARC RCS

Abstract The beam loading compensation is a key part for acceleration of high intensity proton beams in the J-PARC RCS. In the wide-band MA-loaded RF cavity, the wake voltage consists of not only the accelerating harmonic component but also the higher harmonics. The higher harmonic components cause the RF bucket distortion. We employ the RF feedforward method to compensate the multi-harmonic beam loading. The full-digital feedforward system is developed, which compensates the first three harmonic components of the beam loading. We present the results of the beam test with a high intensity proton beam (2.5 × 10 13 ppp). The impedance seen by the beam is greatly reduced, the impedance of the fundamental accelerating harmonic is reduced to less than 25 Ω in a full accelerating cycle, while the shunt resistance of the cavity is in the order of 800 Ω. The performance of the feedforward system is promising for achievement of the design beam power, 1 MW, in the future

サイセンタン ノ サンジゲン イメージング システム : シンゾウ ケッカン ゲカ ニオケル Virtual Reality ギジュツ ノ ユウヨウセイ

滋賀医科大学心臓血管外科では医療用画像を三次元構築し、臓器を立体表示するVirtual Reality (VR) 技術を用いて心臓血管系の3D解析研究を進めている。VRでは臓器の内腔を可視化することができ、また3D構築した画像に直接介入し、従来の2D解析では評価困難であった複雑な構造も術者の視点で直観的に計測できるという利点がある。あらゆる医療画像データを三次元化し, かつ直感的な立体計測が可能なVR技術は, これまでの診断精度を上回る形態学的な情報を臨床医に提示し得ると考えられる。特に外科医にとって有用な手術支援VR画像は, 難易度が高い手術の治療成績を向上させる可能性が高い。Adequate preoperative planning may facilitate successful procedures in cardiovascular surgery. We have newly developed a system the Vesalius 3D suite, combining three-dimensional (3D) image-processing software with an optic-tracking spatial navigation, allowing quick, accessible 3D image interpretation for virtual reality (VR) exploration and measurement of complex anatomy. In this review, we present a novel method of virtual imaging analysis for preoperative planning and simulation in cardiovascular operation using this 3D-VR system. Based on unimodal or multimodal medical imaging data, DICOM data sets can be reconstructed for 3D visualization. Virtually reconstructed images can be viewed on stereoscopic 3D display, revealing each patient’s specific anatomy and the internal structures in exquisite detail. Highly accessible 3D interpretation promptly permits precise and intuitive measurements of repair-relevant anatomical parameters including geometrically complex shapes. This technology may promote understanding of form and function in the cardiovascular system, and facilitate operative procedures in more challenging cases. Furthermore, this system can be especially valuable for any surgeon to gain experience in practicing for rarely-performed procedures or uncommon patient-specific preoperative surgical simulations

A Preliminary Experiment of Volatilization of Minerals in Coal Ash by Chlorination Treatment

Chlorination and volatilization characteristics of minerals in coal ashes were studied for chemical modification of the ash composition and properties. The ash samples were prepared by burning three bituminous coals, a lignite and a brown coal in a muffle furnace at 1088 K (high-temperature ash; HTA) and in an O2 plasma asher (low-temperature ash; LTA). On heating the ashes at 10 K/min to 1273 K in atmospheric chlorine gas flow in a thermobalance reactor, chlorination of minerals was found to take place even without oxygen sink and was followed by vaporization of the metal chlorides formed. Elemental analysis of the original and chlorine-treated HTAs revealed that most of K, Na, Mg and Fe and a portion of Ca were extracted while others such as Si and Al were hardly volatilized. Some pure metal oxides and a carbonate abundant in the ashes were treated at the same conditions. The result showed that Fe2O3 and Fe3O4 were rapidly volatilized in a temperature range of 900 to 1200 K. MgO was slowly but completely volatilized at 1273 K. Chlorination of CaO and CaCO3 occurred at much lower temperatures but vaporization of CaCl2 proceeded very slowly even at 1273 K. Changes in the ash weight with increasing temperature widely varied for the type of the initial ash. The variation was explained on the basis of the initial contents of metal oxides and carbonates. The chlorination treatment resulted in a significant reduction of differences in the mineral compositions, melting point temperatures and acid-base indices of residual solids from HTAs derived from the bituminous coals

Increased penetration of diphenhydramine in brain via proton-coupled organic cation antiporter in rats with lipopolysaccharide-induced inflammation

Uptake transporters in brain microvascular endothelial cells (BMECs) are involved in the penetration of basic (cationic) drugs such as diphenhydramine (DPHM) into the brain. Lipopolysaccharide (LPS)-induced inflammation alters the expression levels and activities of uptake transporters, which change the penetration of DPHM into the brain. A brain microdialysis study showed that the unbound brain-to-plasma partition coefficient (Kp,uu,brain) for DPHM in LPS rats was approximately two times higher than that in control rats. The transcellular transport of DPHM to BMECs was increased when BMECs were cultured with serum from LPS rats. Compared with control rats or BMECs, the brain uptake of DPHM in LPS rats was increased and the intracellular accumulation of DPHM was increased under a high intracellular pH in BMECs from LPS rats, respectively. Treatment of BMECs with transporter inhibitors or inflammatory cytokines had little impact on the intracellular accumulation of DPHM in BMECs. This study suggests that LPS-induced inflammation promotes unidentified proton-coupled organic cation (H+/OC) antiporters that improve the penetration of DPHM into rat brain via the blood-brain barrier

Multiharmonic rf feedforward system for compensation of beam loading and periodic transient effects in magnetic-alloy cavities of a proton synchrotron

Beam loading compensation is a key for acceleration of a high intensity proton beam in the main ring (MR) of the Japan Proton Accelerator Research Complex (J-PARC). Magnetic alloy loaded rf cavities with a Q value of 22 are used to achieve high accelerating voltages without a tuning bias loop. The cavity is driven by a single harmonic (h=9) rf signal while the cavity frequency response also covers the neighbor harmonics (h=8,10). Therefore the wake voltage induced by the high intensity beam consists of the three harmonics, h=8,9,10. The beam loading of neighbor harmonics is the source of periodic transient effects and a possible source of coupled bunch instabilities. In the article, we analyze the wake voltage induced by the high intensity beam. We employ the rf feedforward method to compensate the beam loading of these three harmonics (h=8,9,10). The full-digital multiharmonic feedforward system was developed for the MR. We describe the system architecture and the commissioning methodology of the feedforward patterns. The commissioning of the feedforward system has been performed by using high intensity beams with 1.0×10^{14} proteins per pulse. The impedance seen by the beam is successfully reduced and the longitudinal oscillations due to the beam loading are reduced. By the beam loading compensation, stable high power beam operation is achieved. We also report the reduction of the momentum loss during the debunching process for the slow extraction by the feedforward

Multiharmonic rf feedforward system for beam loading compensation in wide-band cavities of a rapid cycling synchrotron

For the acceleration of very high intensity protons in the 3 GeV rapid cycling synchrotron (RCS) of the Japan Proton Accelerator Research Complex (J-PARC), the beam loading compensation in the rf accelerating cavities is implemented. The magnetic-alloy (MA) loaded cavities, which have a wide-band frequency response, are employed in the J-PARC RCS. The wake voltage in the wide-band MA cavity consists of not only a component of the fundamental accelerating rf, but also the higher harmonics. We developed a multiharmonic feedforward compensation system, which handles the most important three harmonics (h=2,4,6). The function of the multiharmonic feedforward is described. Adjustments of the amplitude and phase patterns for the cancellation of the wake voltage during the acceleration period are not trivial. We developed the commissioning methodology of the feedforward. We describe the methodology in the cases without and with driving the accelerating rf. The commissioning of the systems for 11 cavities in the RCS was successful. We describe the commissioning results and the beneficial effects of the feedforward compensation in the beam operation

Longitudinal painting with large amplitude second harmonic rf voltages in the rapid cycling synchrotron of the Japan Proton Accelerator Research Complex

In the rapid cycling synchrotron (RCS) of the Japan Proton Accelerator Research Complex (J-PARC), the longitudinal painting is important to alleviate the space-charge effects. It is known that the momentum offset injection and applying the second harmonic rf voltage improves the bunching factor, which is defined as the ratio of average and peak current. Our simulation studies show that the large-amplitude second harmonic, 80% to the fundamental, is optimum, and the second harmonic phase sweep improves the bunching factor at the beginning of the injection period. We performed the beam tests of longitudinal painting in the J-PARC RCS. We proved that the longitudinal painting with the 80% second harmonic, the momentum offset of -0.2%, and the second harmonic phase sweep improved bunching factors significantly