Ⅱ-8. Accelerator

RIKEN Accel. Prog. Rep. 47 (2014)

Modification of beam diagnosis chambers in RILAC2 high-energy
beam transport
K. Yamada,∗1 R. Koyama,∗2 T. Nakamura,∗2 M. Hamanaka,∗2 M. Fujimaki,∗1 and N. Fukunishi∗1The vacuum chambers in the high-energy beamtransport line between the RILAC2 and the RRC havebeen modified in order to extend the beam diagnosis
devices such as a beam profile monitor and movable
slits. Figure 1 indicates the schematic view of thebeam line. The vacuum level in the section including
a rebuncher located at S31 (S3-REB) has also beenenhanced by mounting additional vacuum pumps inan arrangement previously presented in report 1. The
modifications are listed as follows.

are mounted on the chamber as well.
• location S31b (just downstream of the S3-REB):
A new small chamber has been installed only for
mounting a wire-scanning beam profile monitor.
This beam profile monitor is used to adjust thebeam trajectory in the S3-REB section by combining with the beam profile monitor at S31a.
• location S41 (just downstream of the singlet
quadrupole (Q) magnet):
A beam profile monitor chamber located at S40(just upstream of the Q-magnet) and a vacuum
gate valve located at S41 have been exchanged
with the aim of checking the degree of dispersion corrected by the Q-magnet. A 220 L/s turbo
molecular pump has been mounted on the S41chamber.
• S6-REB (rebuncher located at the S61):
Two gate valves have been installed at each end of
the S6-REB. This installation enables maintaining
the devices without breaking the vacuum in thelong section between S41 and S71.
• location S64:
A new large vacuum chamber has been installed,
as shown in Fig. 2. A plastic scintillator, a beam
attenuation mesh, a wire-scanning beam profile
monitor, a build up secondary-electron suppressor, a Faraday cup, and a 220 L/min turbo molecular pump have been attached to the chamber.
Two other diagnosis devices are expected to beappended onto the chamber. A fast current transformer (C.T.) has newly been installed just upstream of the chamber.

Fig. 1. Schematic view of high-energy beam transport between RILAC2 and RRC.

∗1∗2• location C22 (just upstream of the wall between
the AVF and RRC vault):
The existing vacuum chamber has been replaced
by a larger one to increase the number of the port
for movable slits that define the beam emittanceof RRC injection by combining with the slits atlocation C21a. A plastic scintillator for time-offlight measurement, a beam attenuation mesh, a
220 L/s turbo molecular pump, and a beam stopper for radiational safety are also mounted on theC22 chamber. A wire-scanning beam profile monitor will be attached on the chamber to check thebeam size on the plastic scintillator.
• location S31a (upstream of the S3-REB):
The existing chamber has been replaced by amiddle-sized chamber used for a standard inRIBF. A 350 L/s turbo molecular pump has newly
been attached to the S31a chamber to improve thevacuum level. A beam attenuation mesh, a wirescanning beam profile monitor, and a Faraday cup

References

RIKEN Nishina Center
SHI Accelerator Service Ltd.

1) K. Yamada et al., RIKEN Accel. Prog. Rep. 45, 99(2012).

Fig. 2. Photograph of the new chamber installed at S64.

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