1

Progress of IR Vacuum Chambers

Chen Peng

May 11,2007

2

Outline

Introduction Mechanical Process Reason for delay

------ BPM Welding

Substitute Chamber Work Plan Summary

3

Introduction

Vacuum chambers in interaction region.

The major chambers of IR are made of oxygen-free Copper.

4

SCQ Chamber

The length of chamber is about 1.4 m.

The chamber is divided into 4 sections: front cylinder pipe with a BPM, bellows, tapered pipe and cylinder Pipe.

BPM’s feedthrough cable

Rotatable receiver

Cooling pipe

RF-bellows

5

Crotch Chamber

Its structure is complicated, on which 8 BPMs will be installed.

Pump pipe, cooling pipe and chamber have been brazed together.

Pump

Cooling pipe

BPM

Flange

Bellows

6

ISPB Chamber

This chamber is about 2.4 m long, with a complicated structure.

Cooling water inlet

Cooling water outlet

Cooling water inlet Cooling water

outlet

BPM

Pump screens

7

Outline

Introduction Mechanical Process Reason for delay

------ BPM Welding

Substitute Chamber Work Plan Summary

8

Mechanical Process(1)

We assumed that the mechanical process was the most difficult part, however, the machining of vacuum chambers was done well and quickly, most of these chambers have been ready to welding.

9

Mechanical Process(2)

10

Outline

Introduction Mechanical Process Reason for delay

------ BPM Welding

Substitute Chamber Work Plan Summary

11

Reason for delay

The delay is mostly attributed to the welding process of BPM.

All the BPMs are made by Kyocera Company, the flange for welding is made of 30 Ni-Cu (cupro-nickels).

BPM

Flange

12

BPM Welding

The position of BPM on chambers

BPM

13

BPM EB-welding

At the first time, the vendor used electron beam for BPM welding test, but they couldn’t reach the ideal level. The leak rate was between 10X-4 and 10X-9mbar.l/s.

Leak detectionEBW test piece

14

BPM EB-welding(1)

During the three months of Electron beam test, they adjusted the parameter of welding angle, depth of melt, etc; however, the figure still couldn’t rise to 10X-10mbar.l/s.

Welding fixture

Welding on test piece

15

BPM EB-welding(2)

The vender considered that the flange material was inhomogeneous and the microelement （ Mn&Fe ） in material would affect welding process; therefore, electron beam couldn’t be welded well.

The content of flange

16

BPM EB-welding(2)

The vender considered that the flange material was inhomogeneous and the microelement （ Mn&Fe ） in material would affect welding process; therefore, electron beam couldn’t be welded well.

The content of flange

17

BPM Welding According to the discussion wi

th Kyocera technicians, the vendor knew that in the internal of BPM, the flange was brazed to ceramic at 780 degree (AgCu28).

They tried to braze BPM on oxygen free-copper at nearly 700 degree, so that they could protect the inner seam when BPM was welded.

And they come to an agreement with Kyocera technicians on this method.

Flange

Pin (Ti)

Inner seam

Ceramic

BPM structure

18

BPM Braze Welding(1)

The vender made some samples to approve it was feasible to braze ， success rate was above 70%.

Braze-welding test sample Leak detection

19

BPM Braze Welding(2)

After being brazed, 2 BPMs’ seams leaked on the first one. 4 BPMs’ seams leaked on the second one.

BPM brazed on crotch chamber

20

BPM Repair-Welding(1)

The vendor advised to repair-welding the first one with the same solder (AgCuIn15),which it was no beneficial to seams; and it broke another 2 seams in BPM.

There are only 4 BPMs working well in each crotch chamber.

The first one The second one

Red is for bad BPM

21

BPM Repair-Welding(1)

The vendor advised to repair-welding the first one with the same solder (AgCuIn15),which it was no beneficial to seams; and it broke another 2 seams in BPM.

There are only 4 BPMs working well in each crotch chamber.

The first one The second one

Red is for bad BPM

22

Outline

Introduction Mechanical Process Reason for delay

------ BPM Welding

Substitute Chamber Work Plan Summary

23

Substitute Chamber

In order to tune beam in storage ring in Nov 2006, we made a pair of substitutes for vacuum chamber in Sept.

Stainless steel crotch chamber

Substitute chamber

24

Substitute Chamber

A stainless steel vacuum chamber was installed in interaction region in Oct, and now the chambers are working well.

Installing the Substitute chamber

25

26

27

Outline

Introduction Mechanical Process Reason for delay

------ BPM Welding

Substitute Chamber Work Plan Summary

28

BPM Repair-Welding(2)

The diameter of flange in BPM is 12.5mm, we will make a hole (ø16mm) on chamber.

We braze BPM to a ring (OD:ø16mm), brazing success rate is 75%.

We weld the ring and chamber with electron beam.

ø16mm

BPM braze-welding test

ø16mm ring(oxygen-free copper)

29

BPM Repair-Welding(2)

According to plenty of tests, we believe that the heat from electron beam has no effect on the brazing seam.

Presently, making holes on chamber is under way. Because the welding seams can’t be dealt with acid, keeping the chamber clean when machining the holes is very important.

EBW

30

Assembly Welding of Crotch Chamber

EBW

After repair-welding of BPM, the crotch chamber will be welded with bellows.

31

Assembly Welding of SCQ Chamber

8 pole BPM brazing test at front cylinder pipe has been done, and the braze technique is adopted.

Cylinder pipe and tapered pipe have been brazed together. At the end of May, we will assembly weld these two parts together

32

Assembly Welding of ISPB Chamber

• Multistage braze welding is very important, in order to maintain the strict tolerance required for installation through the magnets.

• We obtained the experience by means of installing substitute chambers.

• Four sections have been completed.• We need to connect three sections in a string and then weld to the fourth one.

33

Time Schedule

We spend more time on communicating with the vender, and update the progress schedule in time.

Our new schedule is as followed: SCQ Chamber : 8 pole BPM welding, assembly welding (EBW)

May 11 ~ June 5, 2007 Crotch Chamber : BPM repair-welding, assembly welding (EBW)

April 29 ~ May 28 2007 ISPB Chamber : assembly welding (braze)

June 3 ~ July 26, 2007

34

Outline

Introduction Mechanical Process Reason for delay

------ BPM Welding

Substitute Chamber Work Plan Summary

35

Summary

The mechanical process is almost completed. The manufacture of

holes(ø16mm) on crotch chambers is ongoing.

Repair-welding of BPM is a hard project, and should be done step by step,

so that we can minimize the risk of damage.

The IR substitute has been installed in the tunnel and works well.

Assembly welding will be began in June this year, and many technical

problems will be confronted with, however, we have confidence in solving

them ASAP.

36

Thank you