MHATT-CAT 7ID Beamline P5 description and operation

Eric Dufresne, Dohn Arms
Started November 10, 2001

Table of Content:

P5 Description.

The P5 monochromatic shutter on 7ID is housed after the 7ID-B hutch in a 
minihutch. It consists in a fixed white beam stop equivalent to 30 cm of Pb, 
and a monochromatic beam shutter. The white beam stop blocks the white beam 
1400 mm above the ideal floor. The monochromatic beam is 1435 mm above the 
floor. The shutter is used when sending beam to the 7ID-C and D hutches. 

P5 Vacuum problems, Nov 3, 2001.

Starting at 4pm on Saturday Nov 3, 2001, the vacuum in the P5 shutter is poor,
i.e.  enough to trip the ion pump in its tank. The P5 is the shutter inside the 
minihutch after 7ID-B. At the moment,  a turbo pump is running constantly to 
keep the P5 pressure low enough to operate the ion pumps. Below are some 
pictures showing the minihutch and the P5. Note the turbo pump at the moment is 
connected to a vacuum port in 7ID-C. We plan to leak check on 11/12 the P5. We 
suspect that the Be window at the end of the 7ID-B hutch is leaking.
(see Fig. 11-04.3)

At the end of Nov. 2001, Dohn Arms and a member of the APS Vacuum group found
a leak on the exit Be window in 7ID-B, on the white beam window. We suspect 
that the window was damaged during a yearly shielding revalidation. A large 
white beam melted some plastic and Kapton on the window which may have 
strained the window. To solve the problem, we decided to use the monochromatic
window that was previously in 7ID-C and make an offset flange to mount it at 
the right height. This window was installed in January 2002 and the work is 
explained in more details on this link..
The reopened P5 minihutch.

Fig. 11-04.1. P5 inside the 7ID-B minihutch.

The reopened P5 minihutch.

Fig. 11-04.2. P5 inside the 7ID-B minihutch.

The reopened P5 minihutch.

Fig. 11-04.3. The Be window at the end of 7ID-B, upstream of the P5.

P5 January 2002 repair.

On January 22, 2002, Dohn Arms repaired our 7ID-B vacuum problem (see Fig. 01-22.1).
The old window from 7ID-C was installed at the end of 7ID-B and raised with an
offset flange Don Walko and Dohs Arms procured. The broken 7ID-B window will be
sent for repairs soon.  Dohn also installed an additional pumping port in 7ID-C
to pump the P5 and the beam transport without having to reopen the P5 minihutch.
Reopening always has to involve a Health Physics survey, which is a nuisance.
Fig. 01-22.2 and Fig. 01-22.3 show Dohn at work on the new port.
Repaired Be window in 7ID-B.

Fig. 01-22.1. The repaired Be window in 7ID-B. We used the old Be window in 7ID-C and made an offset flange to lift it up.

Dohn hard at work in 7ID-C.

Fig. 01-22.2. Dohn Arms added a new pumping port in 7ID-C so that if a
leak develops like in Nov 2001, then the P5 minihutch does not need to be reopened.

Repumping the beam transport and P5 after the Be window repair.

Fig. 01-22.3. Repumping the beam transport and P5 after the Be window repair.

Back to my homepage (retour vers ma page maison).
Récemment modifié le 04/30/2002
par Eric Dufresne,
Bldg 432 Rm D007 630-252-0274