BISMV & H 0 -H - psb injection VACUUM REQUIREMENTS
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BISMV & H 0 -H - PSB INJECTION VACUUM REQUIREMENTS LIU - PSB meeting 29th October 2012 C. Pasquino, P. Chiggiato, J. Hansen
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BISMV & H 0 -H - psb injection VACUUM REQUIREMENTS. C. Pasquino, P. Chiggiato, J. Hansen. Outline. BISMV vacuum layout; Graphite outgassing tests; Simulation results; PSB injection vacuum layout; Simulation results; SiC outgassing rate measurements; Conclusions and actions. - PowerPoint PPT Presentation
Transcript of BISMV & H 0 -H - psb injection VACUUM REQUIREMENTS
BISMV & H0-H- PSB INJECTION VACUUM REQUIREMENTS
LIU - PSB meeting 29th October 2012
C. Pasquino, P. Chiggiato, J. Hansen
Outline• BISMV vacuum layout;• Graphite outgassing tests;• Simulation results;• PSB injection vacuum layout;• Simulation results;• SiC outgassing rate measurements;• Conclusions and actions.
LIU - PSB meeting 29th October 2012
BISMV – vacuum layout
LIU - PSB meeting 29th October 2012
3 Sputter Ion pumps Starcell 500
2 Sputter Ion pumps Starcell 300
Bismv – gas loads
LIU - PSB meeting 29th October 2012
Unbaked tank = water vapor outgassing
Magnets outgassing, measured by I. Wevers (EDMS 1097059)
Graphite dumps: thermal outgassing
2
9
**
][10*3
2 cmslmbar
htQ OH
2
12
**10*1
2 cmslmbarQH
212
**10*2
)50(2 cmslmbarQ
CH
LIU - PSB meeting 29th October 2012
Graphite outgassing test: pumpdown and thermal outgassing
R4450 LHC collimator graphite Furnace treatment, 2 hours at 950 ◦C Bakeout ≈ 24 hours at 200 ◦C
Measurement procedure: Pumpdown of 24 hours Bakeout Step of ∆T = 25 ◦C from room
temperature to 200 ◦C Same procedure is followed for the
background signal measurement.In a second measurement campaign a thermocouple was inserted directly to the graphite block to check the effective temperature reached by the latter.
LIU - PSB meeting 29th October 2012
Graphite outgassing test: pumpdown
The more the graphite is exposed to air the more it outgas.
1st time: A few hours only after the vacuum firing treatment;
2nd time: Following the first measurement and 24 h exposure to the lab
air;
3rd time: Following the second measurement and
weeks of exposure to lab air.
1st and 2nd measurement ≤4*10-10 mbar l/s cm2
3rd measurement 2*10-09 mbar l/s cm2
Outgassing at 10 hours of pumpdown
EDMS DOCUMENT : 1254422
0.1 1 1010-7
10-6
10-5
10-4
10-3
Q (m
bar l
/s)
t (h)
third measurement second measurement first measurement background
Pumpdown
LIU - PSB meeting 29th October 2012
Graphite outgassing test at different temperatures
0 15 30 45 600
255075
100125150175200225250
T (C
)
t (h)
Graphite Vacuum Chamber
Temperature steps
25 50 75 100 125 150 175 200 22510-13
10-12
10-11
10-10
10-9
10-8
Q (m
bar l
/s cm
2)
T (C)
Q
R4450 Graphite Outgassing
with BG subtracted
Thermal outgassing at 200 ◦C is 4 orders of magnitude higher than at 50 ◦C
Equivalent to 2500 cm2 of SS at RT
0 15 30 45 6010-10
10-9
10-8
10-7
10-6
P to
t (m
bar)
t (h)
P tot
TEMPERATURE
PRESSURE
BISMV1 BISMV2 BISMV3 BISMV410-10
10-9
10-8
P (m
bar)
Position
N2 Equivalent
BISMV tank pressure profile: graphite at 50C
Electrical network – vacuum analogy simulations
LIU - PSB meeting 29th October 2012
Water vapor outgassing at 100 hours of pumpdown; Outgassing at 50 ◦C and at 200 ◦C from the graphite; H2 outgassed from the bulk metal & magnets; Scrapers or pickups are calculated as equivalent to a dump outgassing NO HEATING OF THE SURROUNDING CONSIDERED.
P tot = 3*10-9 mbar
BISMV1 BISMV2 BISMV3 BISMV410-10
10-9
10-8
Parti
al Pr
essu
re (m
bar)
Position
H2 H2O
dump graphite - 50 C
BISMV1 BISMV2 BISMV3 BISMV410-10
10-9
10-8
Parti
al Pr
essu
re (m
bar)
Position
H2 H2O
graphite dump updated surface_200C
BISMV1 BISMV2 BISMV3 BISMV410-10
10-9
10-8
10-7
P (m
bar)
Position
N2 Equivalent
BISMV tank pressure profile: graphite at 200C
P tot = 1*10-8 mbar
+
+
PSB H- Injection: vacuum layout
LIU - PSB meeting 29th October 2012
Linac 4 H-
PSB ring
SIP 1
SIP 2
RF shield
Stripping foil
Internal dump
Gate Valve
LIU - PSB meeting 29th October 2012
Electrical network – vacuum analogy simulations
intertank BSW4 BSW4
10-10
10-9
10-8
Parti
al Pr
essu
re (m
bar)
position
H2 50C H2O
Graphite dump at 50 C
intertank BSW4 BSW4
10-10
10-9
10-8
Pres
sure
(mba
r)
position
Ptot (N2 eq)_50
Ptot = 6*10-9 mbar
Ptot = 3*10-9 mbar
Water vapor outgassing at 100 hours of pumpdown; Outgassing at 50 ◦C and at 175 ◦C from the graphite; NO HEATING OF THE SURROUNDING CONSIDERED.
H2O driven
H2 driven
intertank BSW4 BSW4
10-10
10-9
10-8
Parti
al Pr
essu
re (m
bar)
position
H2 175C H2O
Graphite dump at 175C
intertank BSW4 BSW410-10
10-9
10-8
Pres
sure
(mba
r)
position
If the graphite is treated at the furnace, baked and actively cooled (50 ◦C) the 75 l/s SIP can cope with
this extra gas load.
LIU - PSB meeting 29th October 2012
SiC outgassing rate measurements: pumpdown
EkaSiC T plus and EkaSiC G tested in pumpdown: No cleaning No heat treatment Tested as received
(vacuum fired by the company?)
It outgasses as a metallic surface!
No difference between the two different grades.
0.1 1 1010-8
10-7
10-6
10-5
10-4
Q (m
bar l
/s)
t [h]
BGD SiC Tplus SiC G
LIU - PSB meeting 29th October 2012
SiC outgassing rate measurements: accumulation measurements 1/2
After a bake-out at 150 ◦C, the system is cooled down at room temperature: the variable leak valve is closed in order to isolate the sample from the system.
It is possible to measure the outgassing as a function of the heating temperature.
The evaluation of the background is mandatory.
0 30000 600000.0
3.0x10-7
6.0x10-7
Gas Q
uant
ity (T
orr l
)
accumulation time (s)
Hydrogen Linear Fit of Quantity
Equation y = a + b*xAdj. R-Square 0.99922
Value Standard ErrorQuantity Intercept 1.41302E-8 5.29923E-9Quantity Slope 1.02257E-11 1.64682E-13
LIU - PSB meeting 29th October 2012
SiC outgassing rate measurements: accumulation measurements 2/2
0 30000 6000010-10
10-9
10-8
10-7
10-6
2 15 28 44
Gas Q
uant
ity (T
orr l
)
accumulation time (s)
EkaSiC G outgassing at 50C
By heating the sample, we can evaluate the outgassing as function of different heating temperatures: the last heating steps on the EkaSiC G are on-going.The evaluation of the background as function of the heating temperature is needed to calculate the samples outgassing..
Q H2 Q CH4 Q CO Q CO2
Torr l/s cm2 Torr l/s cm2 Torr l/s cm2 Torr l/s cm2
EkaSiC G 1.2*10-13 1.7*10-15 3.5*10-15 9.9*10-15
Degassing values at room temperature (20 ◦C) with BG subtracted!
We are background
limited…
LIU - PSB meeting 29th October 2012
Conclusions and actions• The BISMV and the PSB H – injection area have been considered from the
vacuum point of view;• The R4450 graphite outgassing has been tested at different temperatures
from room temperature up to 200 ◦C;• The results of the simulations show that the graphite is compatible with
UHV systems only IF:1. Vacuum firing at 950 ◦C for 2 hours;2. In – Situ bake out at 200 ◦C for 24 hours;3. Working temperature of the graphite block T = 50 ◦C.• Outgassing rate measurements of the SiC are on going but from the very
first results, it looks very promising for UHV applications.
