LCLS-XTOD Gas Attenuator

Stewart Shen

shen2@llnl.gov

October 27, 2005 1

LCLS-XTOD Gas Attenuator

LCLS FAC Meeting

October 27, 2005

Stewart Shen, Keith Kishiyama and Marty Roeben

This work was performed under the auspices of the U.S. Department of Energy by the University of California, Lawrence Livermore National Laboratory under Contract No. W-7405-Eng-48.

Stewart Shen

shen2@llnl.gov

October 27, 2005 2

Contents

Requirements

Passive Pumping Design

Performance Analysis

Prototype Plan

Project Schedule

Conclusions

Stewart Shen

shen2@llnl.gov

October 27, 2005 3

Physics Requirements

Be able to reduce the FEL beam intensity by up to

4 orders of magnitude at any energy within the design range (0.8 to 2 keV)

Provide stable, reproducible (to within 1%) attenuation for repeated FEL shots.

Implied Requirements

Provide matched boundary vacuum conditions

Stewart Shen

shen2@llnl.gov

October 27, 2005 4

Use gas to attenuate below 2 keV

Autocad

Gas Attenuator SolidAttenuator

Use Gas

Use Solids

* For a transmission of 10-4

Stewart Shen

shen2@llnl.gov

October 27, 2005 5

Gas Pressure (600 cm)

0

5

10

15

20

25

0 0.5 1 1.5 2 2.5

Photon Energy (KeV)

Pre

ssur

e (T

orr)

Ar

N2

Argon and Nitrogen for 104 Attenuation*

* Based on NIST X-Ray Form Factor, Attenuation, Scattering Tables

Stewart Shen

shen2@llnl.gov

October 27, 2005 6

Nitrogen Pressure Requirements

Required N2 Pressure for Different Attenuation600 cm

0

5

10

15

20

0.0001 0.001 0.01 0.1 1

Attenuation Factor

N2

Pre

ssur

e (T

orr)

1.95 KeV

1 KeV

Stewart Shen

shen2@llnl.gov

October 27, 2005 7

100-cm Design*

Gas Attenuator Design (L=100 cm & A=10000)

0

50

100

150

200

250

300

0.0 0.5 1.0 1.5 2.0 2.5 3.0

Photon Energy (KeV)

Ope

rati

ng N

2 P

ress

ure

(Tor

r)

Stewart Shen

shen2@llnl.gov

October 27, 2005 8

Passive System Design

Physical VariablesChamber Length (3-7.5 m)Overall Length (< 10 m)Aperture (3 mm – 5 mm)# of ports (4- 6)

Stewart Shen

shen2@llnl.gov

October 27, 2005 9

Chamber Length

Overall Length

Pumping (Turbo & Roughing L/s)

Chamber Pressure

Injected Gas (sccm)

Boundary Vacuum Pressure

Design Consideration – Critical Parameters

Stewart Shen

shen2@llnl.gov

October 27, 2005 10

Gas Attenuator Differential Pumping Configurations -Full Scale

Parameter Unit Value Value Configuration Passive 6-port A Passive 6-port B Total Length m 10 8 Gas Chamber Length m 7.50 6.0 Diameter m 0.15 0.15 Port 2 &3 Length m 0.33 0.33 Diameter m 0.15 0.15 Port 4 &5 Length m 0.23 0.23 Diameter m 0.125 0.125 Port 6 &7 Length m 0.23 0.23 Diameter m 0.125 0.125 Total Equivalent Combined Pumping Speed (turbo+scroll)

L/s 720 720

Gas N2 N2 Chamber Pressure for 104 Attenuation

Torr 15.2 19

Max Gas Flow sccm 5053 6276 1st Port Pressure (V2) Torr 0.15 0.19 Last Port Pressure (V7) Torr 1.5x10-6 2.0x10-6

Stewart Shen

shen2@llnl.gov

October 27, 2005 11

10-m 6 port 3-mm Aperture720 L/s Qi = 0 sccm Pump Down

0 150 300 450 600 750 9001 10

81 10

71 10

61 10

51 10

41 10

30.01

0.1

1

10

100

1 103

ChamberPort-2Port-5Port-7

DP-Vacuum

Time (s)

Torr

• Final outgassing rates of 10-9 T-L/s-cm2 is assumed• Scroll Pump Speed vs Pressure is modeled• Turbo Pump Speed vs Pressure is modeled

Stewart Shen

shen2@llnl.gov

October 27, 2005 12

4.298 4.177 tanh 0.469 ln P1

310.673 296.442tanh 0.617 ln P2

Turbo Pumping Speed Modeling

Scroll (Roughing) Pumping Speed Modeling

Stewart Shen

shen2@llnl.gov

October 27, 2005 13

6 port 3-mm Aperture720 L/s Qi = 5053 sccm Normal Operation with N2 Injection

t 0 .01 20

0 4 8 12 16 200

25

50

75

100Nitrogen Gas Flow

Time

T-L

/s Qi t( )

t

0 4 8 12 16 200

25

50

75

100Nitrogen Gas Flow

Time

T-L

/s Qi t( )

t

n 1 10 20000

0 1.25 2.5 3.75 51 10

8

1 107

1 106

1 105

1 104

1 103

0.01

0.1

1

10

100

ChamberPort-2Port-5Port-7

DP-Vacuum

Time (s)

Torr

Stewart Shen

shen2@llnl.gov

October 27, 2005 14

6 port 3-mm Aperture720 L/s Qi = 5053 sccm Normal Operation with N2 Injection

t 0 .01 20

0 4 8 12 16 200

25

50

75

100Nitrogen Gas Flow

Time

T-L

/s Qi t( )

t

0 37.5 75 112.5 1501 10

8

1 107

1 106

1 105

1 104

1 103

0.01

0.1

1

10

100

ChamberPort-2Port-5Port-7

DP-Vacuum

Time (s)

Torr

15.24 Torr

1.5x10-6 Torr

Stewart Shen

shen2@llnl.gov

October 27, 2005 15

PrototypeGas Attenuator Differential Pumping - Passive 3-Port

ConfigurationObjectives

Phase 1

Demonstrate stable control of gas chamber pressure

Validate the vacuum design for intermediate flow

Verify mechanical & thermal stability

Phase 2 (Optional)

Demonstrate stable control of gas chamber pressure

Calibrate the Ion Chamber

Validate the intensity attenuation

Stewart Shen

shen2@llnl.gov

October 27, 2005 16

System ConfigurationPhase-1

Gas Chamber

Port 1,2,3

Scroll

Turbo

Stewart Shen

shen2@llnl.gov

October 27, 2005 17

X-Ray Source Requirements

Within the range of 0.8 – 2 keV

Characteristic Beam

Collimated

Accessible (on site)

Stewart Shen

shen2@llnl.gov

October 27, 2005 18

Soft X-Ray Source @ Bldg. 179Technical Contact: Jim Emig (NTED)Max 10 kV with Be window (~1 mA)

Available after October 05

Power Supply & Vacuum Control

Stewart Shen

shen2@llnl.gov

October 27, 2005 19

2 Views of System with X-ray SourcePhase 2

Stewart Shen

shen2@llnl.gov

October 27, 2005 20

Stewart Shen

shen2@llnl.gov

October 27, 2005 21

LLNL Vacuum LaboratoryBuilding 132 S

RM 1571

Stewart Shen

shen2@llnl.gov

October 27, 2005 22

Condition Specification Design Parameters Unit Total Length m 3.27 3.27 Pumping Turbo-1 Turbo-2 Turbo-3 Scroll Total Equivalent

L/s 150 60 60 20

290

300 70 70 20

490 Gas N2 N2 Max Gas Chamber Pressure

Torr 20 25

Max Gas Flow sccm 4000 5000 1st Port Pressure (V2) Torr <0.4 <0.2 Last Port Pressure (V4) Torr <3.0x10-6 <1.0x10-6

Prototype System Major Parameters

Stewart Shen

shen2@llnl.gov

October 27, 2005 23

Vacuum Modeling- Pump Down

0 100 200 300 400 500 6001 10

81 10

71 10

61 10

51 10

41 10

30.01

0.1

1

10

100

1 103

ChamberPort-2Port-3Port-4

DP-Vacuum

Time (s)

Torr

• Final outgassing rates of 10-9 T-L/s-cm2 is assumed• Scroll Pump Speed vs Pressure is modeled• Turbo Pump Speed vs Pressure is modeled

Stewart Shen

shen2@llnl.gov

October 27, 2005 24

D t P( )

Qi t( ) Q1 C12 P2

P1

V1

0.25 310.673 296.442tanh 0.617ln P2 2.468 P

2 2 4.298 4.177tanh 0.469ln P

2 0.782 P2

Q2 C231.114 D23 10 P

2P

3

2

1 18.958D23 10

2P

2P

3

1 23.413D23 10

2P

2P

3

P3

P2

C12 P1

P2

V2

Q3 C34 P4

P3

0.1 310.673 296.442tanh 0.617ln P3 2.468 P

3 C23

1.114 D23 10 P2

P3

2

1 18.958D23 10

2P

2P

3

1 23.413D23 10

2P

2P

3

P2

P3

V3

Q4 0.1 310.673 296.442tanh 0.617ln P4 2.468 P

4 C34 P

3P

4

V4

t 0 .01 20

0 4 8 12 16 200

20

40

60Nitrogen Gas Flow

Time

T-L

/s Qi t( )

t0 20 40 60 80 100 120

0

5

10

15

20

25P1- Gas Chamber

Time (s)To

rr

Vacuum Modeling- Gas Injection

Stewart Shen

shen2@llnl.gov

October 27, 2005 25

0 20 40 60 80 100 1201 10

8

1 107

1 106

1 105

1 104

1 103

0.01

0.1

1

10

100

ChamberPort-2Port-3Port-4

DP-Vacuum

Time (s)

Torr

0 20 40 60 80 100 1201 10

8

1 107

1 106

1 105

1 104

1 103

0.01

0.1

1

10

100

ChamberPort-2Port-3Port-4

DP-Vacuum

Time (s)

Torr

0 1 2 3 4 51 10

8

1 107

1 106

1 105

1 104

1 103

0.01

0.1

1

10

100

ChamberPort-2Port-3Port-4

DP-Vacuum

Time (s)

Torr

Vacuum Modeling- Normal Operation with injected N2 gas

Stewart Shen

shen2@llnl.gov

October 27, 2005 26

Prototype Testing Program

Procured Components

Delivery IWS/QA Plan

1 Assembly & Alignment

Facility Readiness

3 N2 Gas Injection Tests

2 Integration in Vacuum

Circuits

4 Log-Term Extended Tests

Repair or Modification Repair

or Modification

tion

Test Plan Alignment & Tolerance

Vacuum control Evacuation Base pressure Gas loads

Leak Check Repair or Modification

Vacuum Control Mass-Flow

Control Base pressure

Gas loads/ Pump speed

Repair or Modification

Mechanical Stability Vacuum Control

Base pressure Gas loads/

Pump speed

Repair or Modification

6 Gas Attenuation Tests (Phase 2)

Data Analysis

Data Analysis

Data Analysis

5 Integration with

Soft X-Ray Source & Ionnization Chamber

(Phase 2)

• Facility Ready (132S RM 1571)• IWS Approved (IWS #12599) • Test Plan prepared• Engineering drawings being prepared• QA Plan prepared

Stewart Shen

shen2@llnl.gov

October 27, 2005 27

MKS Type 649 Electronic Pressure Controller

• Fully integrated baratron, mass flow meter, normally closed proportioning control valve and closed loop proportional/integral control electronics

• Flows to 5000 sccm

• Pressure control + 0.2% of full scale

• Time response – 1 sec (excluding system time constants)

Mass Flow Control

Stewart Shen

shen2@llnl.gov

October 27, 2005 28

Gas Attenuator Design Schedule

Stewart Shen

shen2@llnl.gov

October 27, 2005 29

Gas Attenuator Procurement/Installation Schedule

Stewart Shen

shen2@llnl.gov

October 27, 2005 30

LCLS Gas Attenuator Prototype Procurement Cost EstimateVendor Description Part number Unit cost Quantity CostVarian Turbo-V 301 Navigator pump CFF 8" 9698921 $7,775.00 1 $7,775.00Varian Turbo-V 301 Controller, rack mount, 120 vac 9699537 $2,525.00 1 $2,525.00Varian Vent Valve, for standard rack controller 9699843 $665.00 1 $665.00Varian Air cooling kit 9699299 $369.00 1 $369.00Varian Inlet screen DN160 9699304 $129.00 1 $129.00

Varian TriScroll 600 single phase motor, US cord PTS06001UNIV $8,580.00 2 $17,160.00Varian Vacuum pump isolation valve VPI401205060 $675.00 2 $1,350.00

Varian Turbo V70LP Pump CFF 4.5 " 9699366 $4,155.00 2 $8,310.00Varian Turbo V70LP Controller, 120vac 9699505 $1,759.00 2 $3,518.00Varian Vent Valve, for standard rack controller 9699843 $665.00 2 $1,330.00Varian Air cooling kit (V70LP) 9699310 $245.00 2 $490.00Varian Inlet screen DN63 9699300 $65.00 2 $130.00

MKS Type 649 Electronic pressure controller 649A-51T-53C-3-V-T $2,900.00 1 $2,900.00MKS Type 246C Single channel power supply/readout 246C $925.00 1 $925.00MKS Cable connects 649 to 246, 10 feet CB649-1-M1 $55.00 1 $55.00MKS Type 626A Baratron 100 Torr, 8 VCR female 626A12TBE $915.00 5 $4,575.00MKS PDR2000 Digital Power Supply and Readout PDR2000AO $550.00 3 $1,650.00MKS 20 foot cable for Type 626 Baratrons CB2000S-1-M2 $135.00 3 $405.00

Granville-Phillips 370 Stabil-ion Gauge controller 370501-C10-T1 $3,090.00 2 $6,180.00w/ Dual Convectron modulew/ IEEE-488 computer interface module

Granville-Phillips Stabil-Ion Gauge, extended range 370120 $645.00 3 $1,935.00Granville-Phillips Stabil-Ion gauge cable, 25 ft. 360116-25 $205.00 2 $410.00

Leybold Inficon Transpector 2 RGA, C100M TSP2-0211100000 $7,905.00 1 $7,905.00

$70,691.00

Stewart Shen

shen2@llnl.gov

October 27, 2005 31

Conclusions

Gas Attenuator preliminary design is near its completionPrototype design completed and hardware procurement startedProject is on schedule