| Paper | Title | Page |
|---|---|---|
| MOPLS084 | Experimental Comparison at KEK of High Gradient Performance of Different Single Cell Superconducting Cavity Designs | 750 |
|
||
| We have performed a series of vertical tests of three different designs of single cell Niobium superconducting cavities at 2 degrees Kelvin. These tests aimed at establishing that an accelerating gradient of 45 MV/m could be reached in any of the designs, while using the standard KEK surface preparation. The designs tested were the Cornell re-entrant shape (RE), the DESY/KEK low loss shape (LL), and the KEK ICHIRO series. The cavities underwent surface preparation consisting of centrifugal barrel polishing, light chemical polishing, electropolishing, and finally a high pressure water rinse. All three kinds of cavities were used in a series of vertical tests to investigate details of the surface treatment. When using ultra-pure water for the high pressure rinse, the LL cavity reproducibly exceeded a gradient of 45 MV/m, the RE design reproducibly reached a gradient of between 50 MV/m and 52 MV/m, and three of the six ICHIRO cavities reached a gradient of between 45 MV/m and 49 MV/m. | ||
| TUPLS010 | New Beam Transport Line from LINAC to Photon Factory in KEK | 1505 |
|
||
| The e+/e- injector LINAC in KEK usually injects into four rings which are Low Energy Ring (LER) of KEKB (3.5GeV/e+), High Energy Ring (HER) of KEKB(8.0GeV/e-), Photon Factory (PF)(2.5GeV/e-) and Advanced Ring for pulse x-rays (PF-AR)(3.0GeV/e-). While LINAC continuously injects into LER and HER alternately about every five minutes, both of the KEKB rings usually store almost full operating currents. Time for PF or PF-AR, which includes switching time, took about 20 minutes several times a day. During this, the storage currents in KEKB rings decreased, and the optimum points of luminosity tuning had been lost. It had taken more than two hours to recover the luminosity. It is so useful for KEKB to shorten the time for switch LINAC KEKB to/from PF or PF-AR. In summer of 2005, the transport line from LINAC to PF were renewed, in which a DC bending magnet only for PF line apportions electron beam from the end of LINAC to the new line. We succeeded to reduce the occupancy time for PF injection to about five minutes. In this paper design of the new PF beam transport line and the practical performance achieved according to the design are described. | ||
| THPCH052 | Dependence of Transverse Instabilities on Amplitude Dependent Tune Shifts | 2904 |
|
||
| In the Photon Factory electron storage ring, transverse instabilities have been observed in multi-bunch operation mode. The instabilities can be suppressed by amplitude dependent tune shifts, which are induced by the sextupole, octupole and higher order magnetic field. Since four octupole magnets have been installed in the PF ring, we can control the tune shifts, which is caused by the octupole magnetic field, independently of chromaticities, which is caused by sextupole magnetic field. In order to research the suppression mechanism of the instabilities, we measured the dependence of the instabilities on the tune shifts, which are induced by the octupole field. The threshold of the tune shifts, which suppress the instabilities, were observed in the measurement, and it depended on the filling pattern of the bunch train and the beam current per bunch. In addition, we will present the results of the measurement before and after the reconstruction for the straight-sections upgrade at the PF ring, which was carried out in 2005. | ||
| TUOAFI01 | Development for New Carbon Cancer-therapy Facility and Future Plan of HIMAC | 955 |
|
||
| The first clinical trial with carbon beams generated from the HIMAC was conducted in June 1994. The total number of patients treated is now in excess of 2500 as of December 2005. Based on our 10 years of experience with the HIMAC, we have proposed a new carbon-ion therapy facility for widespread use in Japan. The key technologies of the accelerator and irradiation systems for the new facility have been developed since April 2004. The new carbon-therapy facility will be constructed at Gunma University from April 2006. As our future plan for the HIMAC, further, a new treatment facility will be constructed at NIRS from April 2006. The design work has already been initiated and will lead to the further development of the therapy with the HIMAC. The facility is connected with the HIMAC accelerator complex and has two treatment rooms with horizontal and a vertical beam-delivery systems and one room with a rotating gantry. We will report the development for new carbon therapy facility and the design study for new treatment facility with the HIMAC. | ||
|
Transparencies | |
| THPLS036 | Results of the Straight-sections Upgrade of the Photon Factory Storage Ring | 3365 |
|
||
|
At the 2.5-GeV ring of the Photon Factory (PF), a large reconstruction of the lattice around the straight sections* has been accomplished in 2005. As a result, four short straight sections of 1.5 m have been newly created, and the lengths of the existing straight sections have been much improved. For example, the length of the longest straight section has been extended to 9 m from 5 m. The optics has been optimized for installing short-period narrow-gap (in-vacuum) undulators at the new straight sections. The reconstruction work on the ring was held from March to September 2005. In the range over two-thirds of the storage ring, all the quadrupole magnets and all the beam ducts have been renewed and rearranged. Commissioning of the storage ring was started from the end of September 2005 and continued for one month. The operation for the user experiment was resumed from the end of October on schedule. Though we made no in-situ baking after the installation for the beam ducts, the vacuum scrubbing by the synchrotron radiation is running very well. The product of the beam lifetime and the beam current exceeded 700 A min for the operation current 450 mA at the end of December 2005.
*S. Asaoka et al. "New Upgrade Project for the Photon Factory Storage Ring", AIP Conf. Proc. 705, p161 (2004). |
||
| THPLS107 | Possibility of the Beam Injection Using a Single Pulsed Sextupole Magnet in Electron Storage Rings | 3526 |
|
||
| Recently, we succeeded in the beam injection using a single pulsed quadrupole magnet (PQM) at the Photon Factory Advanced Ring (PF-AR). The PQM enables us to inject the beam into the storage ring without the local bump by several pulsed dipole magnets. In addition, since the stored beam is not kicked when the beam passes through the magnetic center of the PQM, we can avoid the coherent beam oscillation, which is often produced by the unclosed local bump. It is important for the top-up injection in electron storage rings as synchrotron radiation sources. However, in the case of the PQM, we have the problem that the beam profile slightly changes turn-by-turn after the excitation of the PQM. In order to solve it, we investigated the possibility of the beam injection using a single pulsed sextupole magnet (PSM) instead of the PQM. Here, we will present the simulation of the beam injection using the PSM. |