Vacuum at the ESRF

H.P. Marques - 64th IUVSTA Workshop – Leinsweiler 2011

current activities that benefit from simulation models

Vacuum at the ESRF

• Overview of the ESRF• Vacuum group activities• MC simulation for Coating• Time based MC simulation for pressure bursts• Cell pressure profile simulation

Vacuum at the ESRF

• The ESRF in numbers

• 3rd generation synchrotron • 6 GeV e-

• 845 m long• 32 cells• 35 active beam lines

• For a uniform filling mode• 200 mA beam current• Average pressure < 10-9 mbar • Beam life time 50-60 h dominated by Tousheck scattering

~200h due residual gas scattering

• 120 000L/s pumping speed installed

Vacuum at the ESRF

• ESRF Vacuum Group

• Vacuum diagnostic tools and interlocking systems• Vacuum systems dimensioning and simulation

• for the beam lines users and the accelerator complex

• Vacuum chambers coatings (NEG, Gold, TiN)• Vacuum measurements

• Pumping speed• Pressure gauges calibration• Photo desorption• Thermal desorption (outgassing)• NEG coating characterization

Sputtering Simulation

0

0,5

1

1,5

2

2,5

-40 -30 -20 -10 0 10 20 30 40

Thic

knes

s (u

m)

Distance to center (mm)

Sputering from 3 cathodes at (-19, 0, 19 mm) at 5e-8mbar 50mA.h/m

Gold

Sputtering Simulation Results

0

0,5

1

1,5

2

2,5

-40 -30 -20 -10 0 10 20 30 40

Thic

knes

s (u

m)

Distance to center (mm)

Gold cathodes (-16, 16 mm)

05000100001500020000250003000035000

‐40 ‐30 ‐20 ‐10 0 10 20 30 40

N.  Pa

rticles

Distance to center (mm)

Vanadium sputtering from 3 cathodes at (‐19, 0, 19 mm)

5.00E‐02

1.00E‐02

5.00E‐03

Sputtering Simulation Issues

0

2000

4000

6000

8000

10000

12000

14000

16000

18000

-30 -20 -10 0 10 20 30

N. P

artic

les

Distance from center (mm)

2e-3

1e-2

8e-2

Pressure Bursts

Simulation of a pressure burst in an ID

Electrical circuit equivalent

{C}

R21

Res2

{NEG}

NEG1

{Q}I1ISRC

GND

GND

{C}

R12

Res2{C}

R22

Res2

{NEG}

NEG2

{Q}I2ISRC

GND

GND

{C}

R13

Res2{C}

R23

Res2

{NEG}

NEG3

{Q}I3ISRC

GND

GND

{C}

R14

Res2{C}

R24

Res2

{NEG}

NEG4

{Q}I4ISRC

GND

GND

{C}

R15

Res2{C}

R25

Res2

{NEG}

NEG5

{Q}I5ISRC

GND

GND

{C}

R16

Res2{C}

R26

Res2

{NEG}

NEG6

{Q}I6ISRC

GND

GND

{C}

R17

Res2{C}

R27

Res2

{NEG}

NEG7

{Q}I7ISRC

GND

GND

{C}

R18

Res2{C}

R28

Res2

{NEG}

NEG8

{Q}I8ISRC

GND

GND

{C}

R19

Res2{C}

R29

Res2

{NEG}

NEG9

{Q}I9ISRC

GND

GND

{C}

R10

Res2{C}

R20

Res2

{NEG}

NEG10

{Q}I10ISRC

GND

GND

{C}

R111

Res2{C}

R211

Res2

{NEG}

NEG11

{Q}I11ISRC

GND

GND

{C}

R112

Res2

{NEG}

NEG12

{Q}I12ISRC

GND

GND

PUMP182L/s

PUMP282L/s

GND

GND

NET2 NET3 NET4 NET5 NET6 NET7

NET8 NET9 NET10 NET11 NET12 NET13

NET14

NET1

NET7b{C}

R11

Res2

{C}

R212

Res2

CV6000 Chamber250mm sections

{V}

V1

{V}

V2

{V}

V3

{V}

V4

{V}

V5

{V}

V6

{V}

V7

{V}

V8

{V}

V9

{V}

V10

{V}

V11

{V}

V12

I?IPULSE

Spice results

0,00E+00

5,00E-06

1,00E-05

1,50E-05

2,00E-05

2,50E-05

0 250 750 1250 1750 2250 2750 3250 3750 4250 4750 5250 5750 6000

Pres

sure

(mba

r)

Length (cm)

0.2

0.4

0.6

0.8

1

Cell 30

upstream

downstream

Upstream

upstream downstream

CV6000

upstream

downstream

Downstream

upstreamdownstream

CV3

upstream

downstream

CV4

upstream

downstream

CV5

upstream

downstream

CV6

upstreamdownstream

CV7

upstream

downstream

CV8

upstream

downstream

CV9

upstream

downstream

CV10

upstreamdownstream

CV11

upstream

downstream

CV12

upstream

downstream

CV13

upstreamdownstream

CV14

upstreamdownstream

CV15

CV15CV12CV11CV10CV8CV5CV4CV3CV6000

CV3

CV 3GND

{2/50}

CV3_R2

Res2

{506*Q_ss*T+0.256*Qx_CV3}CV3_Q1ISRC

GND

CV3_1

{2/50}

CV3_R1

Res2

0.57

CV3_V1

upstreamdownstream

{1/200}

CV3_Pump1

{1/239}

CV3_C_pump1

GND

{2/10.6}

CV3_R4

Res2

{3062*Q_ss*T+1.550*Qx_CV3}CV3_Q2ISRC

GND

CV3_2

{2/10.6}

CV3_R3

Res2

3.5

CV3_V2{1/75}

CV3_Pump2

{1/239}

CV3_C_pump2

GND

{2/13.8}

CV3_R6

Res2

{2300*Q_ss*T+1.164*Qx_CV3}CV3_Q3ISRC

CV3_3

{2/13.8}

CV3_R5

Res2

GND

2.6

CV3_V3

GND GND

Difficult shapes

Simulated pressure profile (no beam)

1E-12

1E-11

1E-10

1E-09

1E-08

upst

ream net2

net3

net4

net5

net6

net7

net8

net9

net1

0ne

t11

net1

2ne

t13

dow

nstre

amcv

3_1

cv3_

2cv

3_3

cv4_

1cv

4_2

cv5_

1cv

5_2

cv5_

3cv

6cv

7cv

8_1

cv8_

2cv

8_3

cv9

cv10

_1cv

10_2

cv10

_3cv

11_1

cv11

_2cv

12_1

cv12

_2cv

12_3

cv13

cv14

cv15

_1cv

15_2

cv15

_3

Cell 30

Cell 30 Pressure Profile (no beam)

1,0E-11

1,0E-10

1,0E-09

1,0E-08

ip1 ip3 ip5 ip6 ip7 ip8 ip9 ip10 ip11 ip12

Pres

sure

(mba

r)

Ion pump reference

Exp

Cell 30 Pressure Profile (no beam)

1,0E-11

1,0E-10

1,0E-09

1,0E-08

ip1 ip3 ip5 ip6 ip7 ip8 ip9 ip10 ip11 ip12

Pres

sure

(mba

r)

Ion pump reference

Exp

Sim

Cell 18 Pressure Profile (no beam)

1,0E-11

1,0E-10

1,0E-09

1,0E-08

IP1 IP2 IP3 IP4 IP5 IP6 IP7 IP8 IP9 IP10 IP11 IP12

Pres

sure

(mba

r)

Ion pump reference

Exp

Sim

Adding beam effects

• Thermal load

• Beam mode / Current

• Photo desorption

• Conditioning

Thermal load

0

10

20

30

40

50

60

70

80

90

Tem

pera

ture

°C

no beam

7/8 + 1

7/8 + 1

16 bunch

Filling modes

0,0E+00

5,0E-10

1,0E-09

1,5E-09

2,0E-09

2,5E-09

3,0E-09

3,5E-09

IP1 IP2 IP3 IP4 IP5 IP6 IP7 IP8 IP9 IP10 IP11 IP12

Pres

sure

(mba

r)

Ion pump reference

no beam

7/8 + 1

7/8 + 1

16 bunch

Adding photo desorption

1,0E-07

1,0E-06

1,0E-05

1,0E-04

1,0E-03

1,0E-02

1,0E-01

1,0E+18 1,0E+19 1,0E+20 1,0E+21 1,0E+22 1,0E+23 1,0E+24

(m

ol/p

h)

D' (ph/m)

Bak

eout

Act

ivat

ion

5h @

180°

c

Usual procedure for new machines

• Estimate total photon flow

• 90% stopped in the absorbers and 10% lost to chamber walls

• Using a PSD yield of 1×10-6 mol/ph to estimate a total gas load

Cell 30 pressure profile simulation

• It is difficult to make these simulation work in a machine that has been in service for long.

• Nevertheless it may be helpful to have a reference to which to compare against real data

ESRF users demands

ESRF users demands

Chamber surface area:25000 cm2

1×10-11 mbar/L/cm2

Q = 2.5 ×10-7 mbar/L !

Summary

• Vacuum modeling is fundamental to the services provided by the vacuum group.

• No single tool, or technique, can provide all the answers to the demands of ESRF accelerator and its users

• To model the accelerator vacuum profile, knowledge of surface outgassing, specially in dynamic conditions, seems more important than a accurate model of the vacuum system