JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
J-PARC, KEK & JAEA, Ibaraki-ken
KEK, Ibaraki
The Beam Based Alignment (BBA) of the BPM is inevitable for precise and absolute beam position measurements. Even though careful fabrication and installation of the BPM detector, it has to be calibrated by using the beam. Usually, it requires that the individual quadrupole magnet is able to be controlled. However, it is not always that case. In addition, scanning over the all BPM is time consuming procedure. The BBA method under coupled QM environment would help to reduce time for calibration. It presents general formula and experiences at J-PARC RCS and parts of results are compared with the ordinal method at J-PARC MR.
J-PARC, KEK & JAEA, Ibaraki-ken
KEK, Tsukuba
MINOTOS, Kunitachi, Tokyo Metropolitan
Morimoto Engineering, Iruma, Saitama
Kyoto University, Radioisotope Research Center, Kyoto-shi
UBE, Ichihara, Chiba
NIRS, Chiba-shi
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
We developed a secondary emission type beam profile monitor with multi ribbon target made of a carbon graphite foil. The carbon graphite foil is excellent in endurance against heat load, and its thickness as 1.6-3.0 micron and low z (=6) are advantage for reducing beam loss. Intense bunch up to 1013 particle per bunch has been measured. Furthermore, the ribbon emits larger amount of electrons than ordinal metal wires because of its larger surface. Therefore the monitor has higher sensitivity, and transverse beam tail has been observed clearly. The monitors were installed in injection transport and injection point of main ring in J-PARC, in order to measure beam profiles by single passing. Normal size target has 32ch ribbons with 2 or 3 mm in width and their length is 200 mm or more each. In this report, target fabrication, basic characteristics of the carbon graphite target, and results of beam measurement will be discussed.
J-PARC, KEK & JAEA, Ibaraki-ken
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
The overview and the present status of residual gas ionization profile monitors (IPMs) for J-PARC will be presented. Measured turn by turn profiles demonstrate clear contributions from dipole and quadupole injection mismatches. Injection tunings by using the IPMs are essential for painting injection tunings of 3 GeV Rapid Cycling Synchrotron (RCS) as well as to measure the emittance. As for the IPMs for RCS (RCS-IPMs), a magnetic guiding field (Bg) which is parallel to an external electric field (Eext) is also used, on the other hands, only the Eext is used for IPM for Main Ring synchrotron (MR-IPM); the Eext applied perpendicularly to the beam axis projects the ionized charged particles on the detector plane. Collecting the ionized ions with no Bg, the beam position at the RCS-IPMs calculated by using the BPMs (PosBPM) and the profile center (PosIPM) by the RCS-IPM suggests that PosIPM=PosBPM/2, and thus the measured beam size is shrink to a half size. Numerical analyses reveal that the fringe field of the electrodes to produce the Eext is the main source. The issue on the profile distortion due to the fringe fields will be discussed together with recovery plans.
Fermilab, Batavia
J-PARC, KEK & JAEA, Ibaraki-ken
Summary of the working group F activities, presented in the closing plenary session.