Drive Beam Generation in CTF3 S. Bettoni (CERN) for the CTF3 commissioning team
Experience with the existing CTF3 vacuum system€¦ · CERN CH-1211 Geneva 23 Wednesday 24th of...
Transcript of 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
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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
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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
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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.
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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).
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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
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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)
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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
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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
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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
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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
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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.
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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
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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:
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Power-Extraction Transfer Structure (PETS)
High-power transfer line
PETS test tank
CTF2 test stand
Layout of PETS experiment
BEAM
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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
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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
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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) ?
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Finished
Thanks for your attention
Daniel Allard (Vacuum technician) in action.
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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”.