experience with the existing ctf3 vacuum system€¦ · cern ch-1211 geneva 23 wednesday 24th of...

J. Hansen CTF3 Collaboration meeting 1

Experience with the existing

CTF3 vacuum systemJan Hansen

CERN CH-1211 Geneva 23

Wednesday 24th of November 2004


Overview

PETS CHICANEGun

Delay Loop

CTF3 Linac

The Delay Loop will have the same type of pumps, gauges and vacuum control system as the CTF3 Linac


Outline

• Base-line for the CTF3 vacuum system.• Existing setup of the CTF3 Linac.

– Vacuum system.– Control and interlock system. – Bakeout system.

• Outgassing measurements.– Acceleration structures.– Beam diagnostic equipment.

• Static and dynamic vacuum pressure in CTF3. – Static pressure in Linac and CHICANE. – Dynamic pressure in PETS experiment.

• Summary and outlook


The base-line for the CTF3 vacuum system

•Vacuum requirements for the CTF3 Linac.–“The vacuum level required being in the region of 10-7 mbar for the LINAC’’. (Design Report)

•Vacuum components. –Use as many vacuum components from LPI, CTF2 and LEP as possible (pumps and gauges).–Use the existing vacuum control units and interlock system from LPI and CTF2.

•Results from outgassing measurements. -Acceleration structures (fabricated at CERN and at ACCEL).

-Beam diagnostic equipment.


Global vacuum system layout

40 MW3 GHz

40 MW3 GHz

30 MW3 GHz

MKS02

MKS03

MKS05

MKS06

MKS11

MKS12

MKS13

G

SHB

PB1 PB2 B1A1 A2 A3 A4 A5 A6 A7 A8 A9 A10 A11 A12

1.5GHz bw 200 MHz3 tw tubes/40 kW each

MKS15EX 25EX 98 EX 27 EX 29 EX 33

LIPS BOCBOC

MKS14 EX 31

A13 A14 A15 A16

40 MW3 GHz

LIPS

40 MW3 GHz

MKS10

30 MW3 GHz

30 MW3 GHz

30 MW3 GHz

30 MW3 GHz

30 MW3 GHz

A17 A18

Why 9 vacuum sectors:•To minimise the acceleration structures to be vented in case of an intervention (all acceleration structures are baked)•Optimum sector size for leak detection.•Limited availability of high pressure water heaters. (3 needed for each sector).


Vacuum layout for sector C30

Interlocks needed to start equipment:• Ion pumps on:Gauge pressure <5x10-5 mbar (only needed to start the ion pumps).

• Sector valves open:Ion pump pressure <1x10-5 mbar (ion pump current equiv. pressure).Access doors are closed.• Gun on:Sector valves open (interlock).

gaugesion pump

klystron

acceleration structure


CTF3 vacuum control system

Vacuum control racks

Gauge controls Ion pump controls

Vacuum sector

Ion current related tothe pressure

Sector valve controls

Interlock Interlock

Multiplexer

Valve control

M312

&OR OR

Vacuum control system designed by: Jean-Pierre Bertuzzi (AT/VAC/IN)


Standard CERN pumping group

VVR

VVT

VVD

VVI

VPR

VPT

Fixed and Mobile pumping usedin CTF3

Secuvac

VGR/P

VVT 2

Pumping groupTurbo pump

Primary pump


Bakeout of sector C30

Structures are baked at 150˚C (with water at high pressure)

Ion pumps and titanium sublimation pumps are baked at 300˚C

Pumping-T baked at 150˚C

•Beam diagnostic equipment is baked at 120˚C

•All stainless steel vacuum chambers are baked at 150˚C

Ion pumps

Titaniumsublimation pump

Wave guides

Acceleration structures

12 channel bakeout rack


Test of acceleration structures

Test stand for acceleration structures.

Acceleration structure

LOADS

rf power

Limit pressure after bakeoutVGP1: 3.2x10-10 mbarVGP2: 1.8x10-9 mbarVGP3: 2.0x10-9 mbar

-The pump configuration is the same as used onacceleration structures previously installed in CTF2.

-Bakeout temperaturesStructures : 140˚C Pumps : 300˚C


Result of acceleration structure rfpower tests

1.00E-09

1.00E-08

1.00E-07

1.00E-06

1.00E-05

1.00E-04

05-11-02 0:00 08-11-02 0:00 11-11-02 0:00 14-11-02 0:00 17-11-02 0:00 20-11-02 0:00 23-11-02 0:00 26-11-02 0:00 29-11-02 0:00 02-12-02 0:00 05-12-02 0:00

VGP3 ERKVGP3 Accel

Pumping with primary pumping system

140˚C bakeout

140˚C bakeoutVenting for cavity inspection(with dry Nitrogen).

rf on (30MW)

rf on (30MW)

-rf on (20MW)-Leak on load-Repaired leak -Ion pump on.

rf on (30MW)

(mbar)

(time)

Observation: For 30 MW rf power after the same conditioning time the pressure is a factor 10 higher without bakeout

Switch onion pump


Beam diagnostic equipment

20MeV

•Screen + camera•SEM grid

SpectrometerScreen + camera

Linac

Wall current monitor(J. Durand;P.Odier)

Spectrometer Lines(T.Lefevre)

Total outgassing before bakeout>1x10-5 mbar l/s.(teststand)Total outgassing after bakeout<1x10-7mbar l/s.(teststand)

Reference: Stainless Steel unbaked outgassing rate <5x10-10mbar l/s cm-2

-Limit pressure 2 month after installation >6x10-8mbar without bakout.-Limit pressure after bakeout<5x10-9mbar.


Vacuum pressure in CTF3 Linac

100165

260

330

331413

460

530

560

630

660

718

738 880

1120

1160

1210

1230

1330

1410

1430

1520

260

305

530

1130

1230

1595

1.00E-09

1.00E-08

1.00E-07

100 300 500 700 900 1100 1300 1500

Linac

Wave guides (Klystron)

mbar

Gauge number

PETS

Static pressure in Linac and waveguide system

Missing acceleration structures and pumps


Vacuum pressure in CHICANE

CHICANE

120

265

340

442

1.00E-08

1.00E-07

120 220 320 420

Gauge number

Pres

sure

(mba

r)

CHICANE

•Static vacuum pressure in CHICANE and spectrometer line (Date:15-11-2004)

•All CHICANE vacuum chambers, flanges and seals are made of aluminium (similar to the old LEP design).

•All pumps and gauges on the CHICANE are made of stainless steel.

Limit pressure without

Bakeout.

IMPORTANT:


Power-Extraction Transfer Structure (PETS)

High-power transfer line

PETS test tank

CTF2 test stand

Layout of PETS experiment

BEAM


Dynamic an static pressure in PETS experiment

vent

CP.

VPI0

2-30

CP.

VPG

02-6

0

CP.

VGR

/P02

-30

CP.VPG

02-60A

PR

Upstream beam current.

Downstream beam current.

PETS layout

Gauge02-60

(Amp)

(Amp)

160

230 260

02.60B

1.00E-08

1.00E-07

160 170 180 190 200 210 220 230 240 250 260

Gauge number

Pres

sure

(mba

r)

PETS Static vacuum pressure

∆P ≈ 2 x 10-5 mbar

Preliminary


Dynamic and static pressure in PETS experiment

vent

CP.

VPI0

2-30

CP.

VPG

02-6

0

CP.

VGR

/P02

-30

CP.VPG

02-60A

PR

PETS layout

Gauge02-60(PETS tank)

Gauge02-30(Linac)

Gauge01-60(High power line)160

230 260

02.60B

1.00E-08

1.00E-07

160 170 180 190 200 210 220 230 240 250 260

Gauge number

Pres

sure

(mba

r)

PETS Static vacuum pressure

Preliminary

∆P ≈ 3 x 10-6 mbar

∆P ≈ 2 x 10-5 mbar

∆P ≈ 1 x 10-5 mbar


Summary and outlook

• Average static pressure in CTF3 Linac is <1x10-8 mbar (This is within design specification).

• Next step.– Analyse the pressure data from the last run (PETS).– Install temperature sensors on the PETS structures (heating?).– Study if we could save conditioning time by baking the waveguides.

– Study if we need to bake the CHICANE, TL, Delay Loop and the Combiner-Ring(‘’1x10-9mbar’’ design report, pressure in CHICANE 1x10-8mbar) ?

– Study what type of sector valves can be used for the Transfer Lines and Combiner-Ring (Standard valves or valves with RF contact) ?


Finished

Thanks for your attention

Daniel Allard (Vacuum technician) in action.


Vacuum pressure in CTF3 Linac

PETS

160

230 260

02.60B

1.00E-08

1.00E-07

160 170 180 190 200 210 220 230 240 250 260

Gauge number

Pres

sure

(mba

r)

PETS•Static vacuum pressure in PETS experiment. (PETS tank and High-power transfer line)•The aperture between the

down stream beam line and the PETS tank is id 6.7 mm.•The high power transfer line has an aperture of id 50 mm and an aperture to the PETS tank of 0.34”x0.42”.

experience with the existing ctf3 vacuum system€¦ · cern ch-1211 geneva 23 wednesday 24th of...

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