372596187

193

RIKEN Accel. Próg. Rep. 24 (1990)

V-2-31. Mounting of a Straight Section Vacuum Chamber

with Slide Guides

T. Nishidono, T. Bizen,¹ H. Daibo, Y. Suzuki,¹ and S.H. Be

Dummy magnet

Support

Fig. 1. Schematic diagram of the experimental model chamber with slide guides. The points of measurement are denoted by numbers.

Fitting cone r i b

				l.D.	O.D.	o	O
Designed	value			201$^0,5	20 !¹«	50¹ ±10'	50- ±10'
		Pin	1	20.005	19.995	49¹ 59' 55'	50¹ 00' 05'
Heasured	value	Pin	2	20.005	19.992	49¹ 59' 58'	50^# 00' 05'
		Pin	3	20.005	19.998	49¹ 59' 50'	49¹ 59' 58'

Fig. 2. Schematic diagram of the slide guide, (a), Mecha-nism of the slide guide; (b), Dimensions of fitting parts.

We manufactured a new chamber mount, namely a slide guide, and mounted a straight-section chamber with ribs for suppressing chamber deformation. An end of the chamber is fixed and allows no chamber motion in any direction before and after bakeout.

Fixed end Taper pin

An experimental model chamber with three slide guides and their structures are shown in Figs. 1. and 2, respectively. A solid lubricant of copper alloys is applied to taper pins (BC6) and fitting cones (LBC3). The chamber is positioned by a taper pin inserted tightly in a fitting cone at room temperaturę. During bakeout, the taper pin is released by thermal expansion of the chamber. Therefore the chamber motion is allowed in any direction during bakeout, but the chamber returns to the original positions of each bakę cycle. This chamber mount is capable of releas-ing a large force caused by the displacement of the chamber on heating.

The displacements of the chamber were mea-sured with 1 scalę dial gauges set in the transverse sections of the chamber.

The maximum temperaturę difference between points m and n in Fig. 1. during bakeout was 10 °C, which caused a 600 ^m-deformation at the end of the chamber. The taper pins were perfact-ly released during bakeout and fit on after bakeout. Figurę 3 (a) shows the displacements of the chamber. The displacements of the chamber and a gird were less than 42 ptm and 12 /im on each point of the measurements, respectively. Moreover the displacement of dummy magnets was negligibly smali, compared with other defor-mations. This means that the position of a beam position monitor (BPM) is ensured within an

Ishikawajima-Harima Heavy Industries Co., Ltd.