IPAC2013 - List of Authors (Ouchi, N.)

Paper	Title	Page
MOPME027	Bunch Length Measurement of 181 MeV Beam in J-PARC Linac	532
	A. Miura, H. Oguri, N. Ouchi, J. Tamura JAEA/J-PARC, Tokai-mura, Japan A. Feschenko, A.N. Mirzojan RAS/INR, Moscow, Russia K. Futatsukawa, T. Miyao KEK, Ibaraki, Japan M. Ikegami J-PARC, KEK & JAEA, Ibaraki-ken, Japan T. Maruta KEK/JAEA, Ibaraki-Ken, Japan
	In J-PARC Linac, an energy and intensity upgrade project has started since 2009 using Annular Coupled Structure (ACS) cavities. Because the longitudinal matching before ACS cavities is additionally required, we decided to employ the bunch shape monitors (BSMs) to measure the longitudinal beam profile. After three years from the start of BSM project, three BSMs were fabricated. All three BSMs were installed during the summer shutdown of 2012. We tried to measure the longitudinal beam profile exited from SDTL cavities. In this paper, we introduce the outline of BSM project, the first data acquisition and related small problems.

THPWO035	Numerical Study on the Effect of Magnetic Shield of a Bunch Shape Monitor in J-PARC Linac	3842
	J. Tamura, H. Ao, A. Miura, N. Ouchi JAEA/J-PARC, Tokai-mura, Japan M. Ikegami J-PARC, KEK & JAEA, Ibaraki-ken, Japan T. Maruta KEK/JAEA, Ibaraki-Ken, Japan T. Miyao, K. Takata KEK, Tokai, Ibaraki, Japan
	In the annual shutdown period of 2012, three bunch shape monitors (BSMs) have been installed to the J-PARC linac beam transport line at the downstream of the 181-MeV separated DTL. To measure the longitudinal micro-bunch shape, the BSM detects the electrons produced by the accelerated protons hitting the negatively energized wire. Due to the space limitation, the each BSM is installed at the center of the quadrupole doublet, where the fringe field from the quadrupole magnets exists. It has been observed that the fringe field significantly affects the orbit of the emitted electrons. To shield the magnetic field, iron plates have been inserted to the spaces between the quadrupole magnets and BSM. This causes changes of the total magnetic flux density (GL) and the amount of quadrupole component of the fringe field. In this paper, numerical estimation of the shield effect is presented.

THPWO036	Annular-Ring Coupled Structure Linac for the J-PARC Linac Energy Upgrade	3845
	H. Ao, H. Asano, Y. Nemoto, N. Ouchi, J. Tamura JAEA/J-PARC, Tokai-mura, Japan F. Naito, K. Takata KEK, Ibaraki, Japan
	The linac of Japan Proton Accelerator Research Complex (J-PARC) is the injector to the 3-GeV rapid cycle synchrotron. In order to increase the beam power of the synchrotron, the task of the 400-MeV energy upgrade of the linac started from March 2009. Following the 191-MeV Separated-type DTL, the 25 modules of the Annular-ring Coupled Structure (ACS) linac will be added from August 2013. The operating frequency and the accelerating field E0 of the ACS are 972 MHz and 4.2 MV/m, respectively. The cavity fabrication of the ACS has been almost finished, and then the completed cavities are stored in the J-PARC site. Currently, pumps and vacuum components are being installed on the cavities for the test of vacuum condition. For the pulsed beam of J-PARC, the vacuum pressure have to be less than 10^-6 Pa in order not to exceed 0.1 W/m beam loss. In this paper, we present the R&D results to reduce the vacuum pressure using the stored ACS cavity and the current status of the energy upgrade.

Paper

Title

Page

Bunch Length Measurement of 181 MeV Beam in J-PARC Linac

532

A. Miura, H. Oguri, N. Ouchi, J. Tamura
JAEA/J-PARC, Tokai-mura, Japan
A. Feschenko, A.N. Mirzojan
RAS/INR, Moscow, Russia
K. Futatsukawa, T. Miyao
KEK, Ibaraki, Japan
M. Ikegami
J-PARC, KEK & JAEA, Ibaraki-ken, Japan
T. Maruta
KEK/JAEA, Ibaraki-Ken, Japan

In J-PARC Linac, an energy and intensity upgrade project has started since 2009 using Annular Coupled Structure (ACS) cavities. Because the longitudinal matching before ACS cavities is additionally required, we decided to employ the bunch shape monitors (BSMs) to measure the longitudinal beam profile. After three years from the start of BSM project, three BSMs were fabricated. All three BSMs were installed during the summer shutdown of 2012. We tried to measure the longitudinal beam profile exited from SDTL cavities. In this paper, we introduce the outline of BSM project, the first data acquisition and related small problems.

THPWO035

Numerical Study on the Effect of Magnetic Shield of a Bunch Shape Monitor in J-PARC Linac

3842

J. Tamura, H. Ao, A. Miura, N. Ouchi
JAEA/J-PARC, Tokai-mura, Japan
M. Ikegami
J-PARC, KEK & JAEA, Ibaraki-ken, Japan
T. Maruta
KEK/JAEA, Ibaraki-Ken, Japan
T. Miyao, K. Takata
KEK, Tokai, Ibaraki, Japan

In the annual shutdown period of 2012, three bunch shape monitors (BSMs) have been installed to the J-PARC linac beam transport line at the downstream of the 181-MeV separated DTL. To measure the longitudinal micro-bunch shape, the BSM detects the electrons produced by the accelerated protons hitting the negatively energized wire. Due to the space limitation, the each BSM is installed at the center of the quadrupole doublet, where the fringe field from the quadrupole magnets exists. It has been observed that the fringe field significantly affects the orbit of the emitted electrons. To shield the magnetic field, iron plates have been inserted to the spaces between the quadrupole magnets and BSM. This causes changes of the total magnetic flux density (GL) and the amount of quadrupole component of the fringe field. In this paper, numerical estimation of the shield effect is presented.

THPWO036

Annular-Ring Coupled Structure Linac for the J-PARC Linac Energy Upgrade

3845

H. Ao, H. Asano, Y. Nemoto, N. Ouchi, J. Tamura
JAEA/J-PARC, Tokai-mura, Japan
F. Naito, K. Takata
KEK, Ibaraki, Japan

The linac of Japan Proton Accelerator Research Complex (J-PARC) is the injector to the 3-GeV rapid cycle synchrotron. In order to increase the beam power of the synchrotron, the task of the 400-MeV energy upgrade of the linac started from March 2009. Following the 191-MeV Separated-type DTL, the 25 modules of the Annular-ring Coupled Structure (ACS) linac will be added from August 2013. The operating frequency and the accelerating field E0 of the ACS are 972 MHz and 4.2 MV/m, respectively. The cavity fabrication of the ACS has been almost finished, and then the completed cavities are stored in the J-PARC site. Currently, pumps and vacuum components are being installed on the cavities for the test of vacuum condition. For the pulsed beam of J-PARC, the vacuum pressure have to be less than 10^-6 Pa in order not to exceed 0.1 W/m beam loss. In this paper, we present the R&D results to reduce the vacuum pressure using the stored ACS cavity and the current status of the energy upgrade.