Kirsten Zapfe - TESLA Collaboration Meeting, LAL Orsay, 6.-8. Sept. 2004

Status of the TTFStatus of the TTF--II Vacuum II Vacuum SystemsSystems

Kirsten Zapfe, DESYTESLA Collaboration Meeting

LAL Orsay, Sept. 7, 2004

Common effort by many groupsCommon effort by many groupsSpecial thanks to members of vacuum group MVPSpecial thanks to members of vacuum group MVP

HASYLAB, MVA, DESYHASYLAB, MVA, DESY--ZeuthenZeuthen, ZM,, ZM,BESSY, diagnostic groups and experimentsBESSY, diagnostic groups and experiments

Kirsten Zapfe - TESLA Collaboration Meeting, LAL Orsay, 6.-8. Sept. 2004

Outline

� Experience from TTF-I

� TTF-II Vacuum System

� Particle Cleanliness

� Vacuum Control and Interlock System

� Present Status

� Concluding Remarks

Kirsten Zapfe - TESLA Collaboration Meeting, LAL Orsay, 6.-8. Sept. 2004

Experience from TTF-I

� Reliable and robust system

� no major vacuum break down

� Several leaks in modules after cool down and warm up

� no influence on beam operation

� special treatment for venting

Ê improvements necessary

1

1

3

M1

1

5

6

3

M2

2

5

7

1

M3

3

MS

1

1

3

M1*

1

1

1

M3*

1

1

1

M4

1

1

M5

2

2

0

M2*

isolation - air

He - beam

He - isolation

coupler - beam

isolation - beam

# leaks

# cool/warm

Kirsten Zapfe - TESLA Collaboration Meeting, LAL Orsay, 6.-8. Sept. 2004

TTF-II Vacuum System

� Overall system

� 360 m beam vacuum

Ê 60 m cold (2 K), 3 sections

Ê 300 m room temperature

� 50 m coupler vacuum

� 60 m isolation vacuum

Kirsten Zapfe - TESLA Collaboration Meeting, LAL Orsay, 6.-8. Sept. 2004

TTF-II Vacuum System

� Pressure requirements

� beam: pav ≤ 10-8 mbar

� gun: p < 10-10 mbar

� close to cold sections: p < 10-10 mbar

� Pumping/pressure measurement� > 100 sputter ion pumps =

Ê pressure information

� > 50 titanium sublimation pumps =

� Segmentation � 25 valves

� Large number of components� nearly no cm of free space left

Kirsten Zapfe - TESLA Collaboration Meeting, LAL Orsay, 6.-8. Sept. 2004

TTF-II Vacuum System

� RF-losses Ê to be minimized downstream of BC2

� rf-shielded bellows and pump connections

� rf-shielded valves for diameter < 60 mm

� vacuum chamber material

Ê copper coated stainless steel

Ê copper with stainless steel flanges

(induction brazing)

BC3

Kirsten Zapfe - TESLA Collaboration Meeting, LAL Orsay, 6.-8. Sept. 2004

Particle Cleanliness

� Superconducting cavities operating at high gradients � dust/particle cleanliness is a must

� cavities = huge cryo pump

� Mirrors for high intensity X-ray beams

� cracked hydrocarbons destroy optical properties

� dust/particles might destroy coherence properties

Ê complete vacuum system treated similar as sc. cavities

exception: bypass

Minimize risk of particle and gas contamination of Minimize risk of particle and gas contamination of cavities and optical componentscavities and optical components

Kirsten Zapfe - TESLA Collaboration Meeting, LAL Orsay, 6.-8. Sept. 2004

Particle Cleanliness

� Appropriate design

� avoid hidden corners

� Fabrication techniques

� welding of cleaned parts in clean room

removable rf-shield

Kirsten Zapfe - TESLA Collaboration Meeting, LAL Orsay, 6.-8. Sept. 2004

Particle Cleanliness

� Cleaning methods

� prepare particle and hydrocarbon free UHV components

� new cleaning facility

Ê separate cleaning of sc. cavities and vacuum components

Ê clean room class 10.000/100

Ê cleaning steps similar to cavity preparation

HASYLAB/MVP cleaning facility

Kirsten Zapfe - TESLA Collaboration Meeting, LAL Orsay, 6.-8. Sept. 2004

Particle Cleanliness

Kirsten Zapfe - TESLA Collaboration Meeting, LAL Orsay, 6.-8. Sept. 2004

Particle Cleanliness

� Installation procedures

� local clean rooms

� oil free pump stations

� pump down/venting procedures

Kirsten Zapfe - TESLA Collaboration Meeting, LAL Orsay, 6.-8. Sept. 2004

Vacuum Control System

� Self safe operation of all components

� Integral part of TTF control system

Kirsten Zapfe - TESLA Collaboration Meeting, LAL Orsay, 6.-8. Sept. 2004

Vacuum Interlock System

� Valves closed by pressure increase

� conditions depending on location in

accelerator

Ê gun, cold modules, room temperature

sections

� Fast shutter to protect accelerator

from sudden vacuum break

� located directly downstream of last

cold module

� total closing time < 19 ms

Kirsten Zapfe - TESLA Collaboration Meeting, LAL Orsay, 6.-8. Sept. 2004

Present Status

� Installation

� most sectors finished in Feb 04

� last components and modifications Jun 04 – Aug 04

� system test of vacuum interlock still needs to be completed

BC2

Module InterconnectACC3/BC3

OTR/wire scanner

Gun

Kirsten Zapfe - TESLA Collaboration Meeting, LAL Orsay, 6.-8. Sept. 2004

Present Status

Bypass

Collimator/Bypass

Wirescanner/Undulator

LOLA

Dipole magnet/Dump

Material Test Stand (PBA)

Kirsten Zapfe - TESLA Collaboration Meeting, LAL Orsay, 6.-8. Sept. 2004

Concluding Remark

� Installation of TTF-II vacuum system completed in time

� common effort by many groups

� Huge effort to prepare hydrocarbon and particle free UHV system

� Next steps

� close final gap in ACC6 after dark current measurements

… (smooth beam operation)

� prepare future installations

Ê 3rd harmonic cavity

Ê BPM test station

Ê extension of EOS

Ê seeding option

Ê…