LCGT Vacuum System 120123 　 VAC (YS)

1

1. Overview

Items** two beam tubes of 3-km long and 800 mm in diameter** optical baffles distributed at every 12 meter in the beam tubes** beam monitor target inserted in the beam tubes** chambers for the mirrors with suspension and vibration-isolation devices ** vacuum pumping system** overall layout

Interfaceall of the subsystems

** choice of materials for components used in cryostat, optical devices, vibration-isolation devices, , …** interferometer layout and operation sequence

cf. vacuum system philosophy in accelerator** beam dynamics and vacuum system have to be designed simultaneously.** choice of materials having low outgassing is most important.** mechanical and electric design has to be simple.** materials properties have to be examined and measured before choosing.

(KEK Internal 07-17)

** We predict the noise dx due to the residual gas (water) molecules;for dx = 1×10-21 m/√Hz@100 Hz (safety margin of 10),the pressure in the beam tubes is to be kept at 2×10-7 Pa.

(h=3×10-24 /(Hz)1/2 @100Hz corresponds to dx=1×10-20 m/(Hz)1/2)

<<scattering effect due to residual gas>>

120123 　 VAC (YS)

** For long-term and stable operation of the interferometer, the vacuum system is to be designed so as to minimize the maintenance work, and so as to shorten the pump-down time. A long lifetime of the vacuum component and low outgassing is required.

<<minimize the maintenance work>>

Ti cathode

Penning cell

Required Pressure ： in the order of 10-7 Pa, or lower

2

LCGT Vacuum System

2. System design

LCGT Vacuum System 120123 　 VAC (YS)

ETMYA

ITMY

ETMXAITMX

IP TMP

FL P

BSPRM PR3 PR2

SRM

SR3

SR2

PD

MCF

MC

3000 m

double chambers (2.4 and 1.5 m in dia.)//GASF + I-Pendulum + cryogenic//

chambers (1.5 m in dia./2 m for BS)//GASF + I-Pendulum//

chambers (2 m in dia.)//stack + D-Pendulum//

iLCGT iLCGT

MMT

ETMYB

ETMXB

less changes “i” to “b”

3

2. System design

120123 　 VAC (YS)

Electro-polished tube of 12 m long 4

LCGT Vacuum System

beam tube (478 of 12-m long and 0.8 m in diameter)

2. System design

** “surface passivation” is performed by electro-polish followed by bake.expected outgassing rate is on the order of 10-8 Pa m3 m-2 s-1, or lower.the surface roughness is Rmax 3 mm, Ra 0.5 mm.

** “flange connection” with metal O-ring gasket (silver plated) is chosen.humidity test of the gasket shows erosion proof.

** tubes of “mirror finish by Electro-Chemical Buffing” is to be installed in the mid region of 800-m long. the surface roughness is Rmax 0.2 mm, Ra 0.03 mm.

N=(h/d)/(L/R)

** estimated scattered light noise at Kamiokadx = 3×10-21 m/√Hz@30Hz (tube vibration amplitude=1×10-11 m/√Hz assumed )

** For more margin, baffles at “every 12 meters”. dx = 5×10-22 m/√Hz** For randomizing phase 　 of edge-scattered light, baffles with “saw-tooth edge”.

120123 　 VAC (YS)

5

LCGT Vacuum System

optical baffle (every12-m along the arm, 40-mm in height, 45-degree tilted)

2. System design

** measured outgassing rate of DLC is 4×10-9 Pa m3 m-2 s-1

120123 　 VAC (YS)

真空

6

LCGT Vacuum System

optical baffle (diamond-like-carbon/DLC coated)

2. System design

** 17 of 21 chambers are operated at room temperature, 4 for cryogenic system** installed materials of elastomer and plastomer should be investigated.

** Although the aluminum-coated thin PET (polyethylene terephtalate) film is suitable material for thermal shield, the outgassing rate is higher than those of metal surfaces.

** Outgassing rate of a PET film of 12 micrometer thick is measured. The rate decreases to 10-6 Pa m3 s-1 m-2 for about 10h, then reaching to the order of 10-8 Pa m3 s-1 m-2 for 200h.

** Water molecules absorbed in film is possibly diffused to the surfaceand desorbed with a long period of 100 hours.

120123 　 VAC (YS)

7

LCGT Vacuum System

chambers

2. System design

** pumping unit consisted of dry-pump, TMP and ion-pump is distributed “every 100 meters” along tubes.

ETMXITMX

IP TMP

FL P

3000 m

** expected pump-down scheme (a 3-km arm)to 1 Pa >> few days by dry-pumpto 10-6 Pa >> 50 hours by TMPto 10-7 Pa >> 500 hours by IP

(based on the ougassing rate in test tubes)

** pumping speed of the unit (100 m)600 m3/h >> dry-pump2000 L/s >> TMP500 L/min >> TMP foreline pump1000 L/s >> IP

120123 　 VAC (YS)

DRY P

8

LCGT Vacuum System

pumping system (dry-pump and ion-pump)

2. System design

control signal 0/1

pressure readout

120123 　 VAC (YS)

9

LCGT Vacuum System

vacuum system control

2. System design

arm tunnel, center/end room

BA gaugeULVAC GI-M2

controller

PLCYokogawa

A/DYokogawa

MW100

Micro IOC

Center controlEPICS

Pirani gaugeConvectron type

Gate valve（ actuator ）

Ion pumpVARIAN type

Ion pumpGamma type

Ethernet

RS485

→ status: 3 ← control: 3

→ status: 4

← control: 2

→ status: 2← control: 1

controller

controller

controller

controller

A gate valves of large diameter takes 40 seconds for closing.

120123 　 VAC (YS)

ETMYA

ITMY

ETMXAITMX

BSPRM PR3 PR2

SRM

SR3

SR2

PD

MCF

MC

3000 m

iLCGT iLCGT

MMT

ETMYB

ETMXB

bLCGT HR Center HR Chord Center Center of Mass

　 x [m] y [m] x [m] y [m] x [m] y [m]PRM -19.46123288 0.21377918 -19.46120738 0.21377925 -19.51120721 0.21364765ETMX 3.026507E+03 -0.093909 3.026507E+03 -0.093909 3.026582E+03 -0.093909 ETMY 0.060725 3.023222E+03 0.060725 3.023222E+03 0.060725 3.023297E+03PR2 -4.7006812 0.25262878 -4.69784943 0.25267014 -4.64785476 0.253400400SRM 0.13541083 -19.41723194 0.13541104 -19.41720645 0.13501125 -19.46720485SR2 0.25343357 -4.65710099 0.25349012 -4.65426948 0.25448854 -4.60427945SR3 -0.10002163 -15.71840442 -0.10001528 -15.71808665 -0.1010137 -15.76807668PR3 -15.7637214 -0.04148993 -15.76340359 -0.04148529 -15.81339825 -0.04221555BS -7.63E-16 -6.94E-18 -7.63E-16 -6.94E-18 0.02828427 -0.02828427ITMX 26.50720079 -0.09390876 26.50720439 -0.09390876 26.43220439 -0.09390876ITMY 0.06072497 23.22189738 0.06072497 23.22190098 0.06072497 23.14690098

iLCGT HR Center HR Chord Center Center of Mass

　 x [m] y [m] x [m] y [m] x [m] y [m]PRM -19.51677794 0.21417189 -19.51675245 0.21417196 -19.56675227 0.21404036ETMX(iEOAX) 3.001576E+03 -0.093237 3.001576E+03 -0.093237 3.001626E+03 -0.093237 ETMY(iEOAY) 0.061257 2.998291E+03 0.061257 2.998291E+03 0.061257 2.998341E+03PR2 -4.7281891 0.25309529 -4.72535740 0.25313951 -4.67536350 0.253920280SRM 0.13550922 -19.47206837 0.13550943 -19.47204288 0.13510964 -19.52204128SR2 0.25374881 -4.68452802 0.25380268 -4.68169646 0.25475388 -4.63170551SR3 -0.07797132 -15.7185301 -0.07796549 -15.71821231 -0.07888163 -15.76820392PR3 -15.76285711 -0.06258281 -15.76253931 -0.06257763 -15.81253268 -0.06339185BS -4.09E-16 3.47E-18 -4.09E-16 3.47E-18 0.02832301 -0.02824548ITMX(iIAOX) 53.21470655 -0.09323681 53.21471015 -0.09323681 53.16471015 -0.09323681ITMY(iIAOY) 0.06125676 49.92936491 0.06125676 49.92936851 0.06125676 49.87936851

less changes “i” to “b”

10

LCGT Vacuum System

layout

2. System design

120123 　 VAC (YS)

ETMYA

ITMY

ETMXAITMX

BSPRM PR3 PR2

SRM

SR3

SR2

PD

MCF

MC

3000 m

iLCGT iLCGT

MMT

ETMYB

ETMXB

i-b HR Center HR Chord Center Center of Mass

　 delta x [mm] delta y [mm] delta x [mm] delta y [mm] delta x [mm] delta y [mm]PRM -55.545 0.393 -55.545 0.393 -55.545 0.393ETMX -24931.300 0.672 -24931.300 0.672 -24956.300 0.672ETMY 0.532 -24931.340 0.532 -24931.340 0.532 -24956.340PR2 -27.508 0.467 -27.508 0.469 -27.509 0.520SRM 0.098 -54.836 0.098 -54.836 0.098 -54.836SR2 0.315 -27.427 0.313 -27.427 0.265 -27.426SR3 22.050 -0.126 22.050 -0.126 22.132 -0.127PR3 0.864 -21.093 0.864 -21.092 0.866 -21.176BS 0.000 0.000 0.000 0.000 0.039 0.039ITMX 26707.506 0.672 26707.506 0.672 26732.506 0.672ITMY 0.532 26707.468 0.532 26707.468 0.532 26732.468

11

less changes “i” to “b”

LCGT Vacuum System

layout

2. System design

x

y

Yopthorizontal plane at center room

horizontal plane at X end

Y arm

optical plane of interferometerX arm

BS

ETMX

ETMY

X arm

Y arm

ITMXITMY

Xopt

Yopt

O

Xopt

O (BS)

iLCGT

1/300

120123 　 VAC (YS)

horizontal plane at Y end

12

LCGT Vacuum System

layout

2. System design

** floors for installing chambers; horizontal

x

y

Yopthorizontal plane at center room

horizontal plane at X end

Y arm

optical plane of interferometerX arm

Xopt

O (BS)

120123 　 VAC (YS)

eX

eY

eZ

0.9999944444 0.0000000000 0.0033333148

0.0000111110 0.9999944444 0.0033333148

0.0033332962 0.0033333333 0.9999888889

ex

ey

ez

0.9999927478 0.0000000000 0.0038084338

0.0000126947 0.9999944444 0.0033333091

0.0038084127 0.0033333333 0.9999871923

eRXx

eRXy

eRXz

0.9999944444 0.00000952935 0.0033333011

0.0000000000 0.99999591356 0.0028588213

0.0033333148 0.00285880545 0.9999903580

eRYx

eRYy

eRYz

horizontal plane at Y end

13

LCGT Vacuum System

layout

2. System design

** unit vectorsin each coordinate

eX

eY

eZ

** transformation matrix for 4 sets of coordinates

** transformation matrix for 4 sets of coordinates

x

y

Yopthorizontal plane at center room

horizontal plane at X end

Y arm

optical plane of interferometerX arm

Xopt

O (BS)

120123 　 VAC (YS)

X

Y

Z

0.9999944444 0.0000000000 0.0033333148

0.0000111110 0.9999944444 0.0033333148

0.0033332962 0.0033333333 0.9999888889

x

y

z

0.9999927478 0.0000000000 0.0038084338

0.0000126947 0.9999944444 0.0033333091

0.0038084127 0.0033333333 0.9999871923

xRX

yRX

zRX

OXopt

0.9999944444 0.00000952935 0.0033333011

0.0000000000 0.99999591356 0.0028588213

0.0033333148 0.00285880545 0.9999903580

xRY

yRY

zRY

OYopt

horizontal plane at Y end

14

LCGT Vacuum System

layout

2. System design

** descriptionin other coordinate

x

y

Yopthorizontal plane at center room

horizontal plane at X end

Y arm

optical plane of interferometerX arm

BS

ETMX

ETMY

X arm

Y arm

ITMXITMY

Xopt

Yopt

O

Xopt

O (BS)

iLCGT

1/300

120123 　 VAC (YS)

horizontal plane at Y end

15

LCGT Vacuum System

layout

2. System design

500 m

** a set of two 1.5-km long interferometer for geophysics

120123 　 VAC (UI)

16

LCGT Vacuum System

 

four coordinates

120123 　 VAC (UI)

17

LCGT Vacuum System

Center room coordinate

Optical coordinate

 

axis

axis

axis = axis

axis

+𝜽

−𝝀

120123 　 VAC (UI)

18

LCGT Vacuum System

** Transformation of coordinate from Optical coordinate to Center room coordinate

bLCGT m単位： f(x,y,z) x y zETMX HR Center 3026.49038516780000000 - 0.09390823838321690 10.08861431483210000ETMX HR Chord Center 3026.49038516780000000 - 0.09390823838321690 10.08861431483210000ETMX HR Center of Mass 3026.56538475114000000 - 0.09390823838321690 10.08886431344320000

ETMY HR Center 0.10084051722090500 3023.20510427612000000 - 10.07712618371120000ETMY HR Chord Center 0.09431580265810740 3023.20509427618000000 - 10.07714789942620000ETMY HR Center of Mass 0.09431663598681110 3023.28009385951000000 - 10.07739789803730000

BS HR Center 0.00000000000000000 0.00000000000000000 0.00000000000000000BS HR Chord Center 0.00000000000000000 0.00000000000000000 0.00000000000000000BS Center of Mass 0.02828442713439690 0.02828411286473020 0.00000000000000000

ITMX HR Center 26.50705248557570000 - 0.09390823828321740 0.08866987255763190ITMX HR Chord Center 26.50705608555570000 - 0.09390823828321740 0.08866988455756530ITMX HR Center of Mass 26.43205650221890000 - 0.09390823828321740 0.08841988594644260

ITMY HR Center 0.06098265229042840 23.22176836910060000 - 0.07720347912630740ITMY HR Chord Center 0.06098265233042810 23.22177196908060000 - 0.07720349112624070ITMY HR Center of Mass 0.06098181900172440 23.14677238574850000 - 0.07695349251511800

PRM HR Center - 19.46112238762260000 0.21377861233114500 - 0.06558301125094960PRM HR Chord Center - 19.46109688777040000 0.21377806233420100 - 0.06558292441809870PRM HR Center of Mass - 19.51109644145810000 0.21364646306531400 - 0.06574915092795390

PR2 HR Center - 4.70065227835122000 0.25262737650287900 - 0.01651094153946850PR2 HR Chord Center - 4.69782052362359000 0.25266873627310100 - 0.01650164022447560PR2 HR Center of Mass - 4.64782612325549000 0.25339899221608900 - 0.01633742643677190

PR3 HR Center - 15.76363428549650000 - 0.04148969949974860 - 0.05240714708332500PR3 HR Chord Center - 15.76331647721050000 - 0.04148505952552650 - 0.05240610318912440PR3 HR Center of Mass - 15.81331086757870000 - 0.04221531546851520 - 0.05257031694349490

SRM HR Center 0.13519433190090900 - 19.41712406618960000 0.06517511381704010SRM HR Chord Center 0.13519454218296300 - 19.41709857633120000 0.06517502955084160SRM HR Center of Mass 0.13479419886930900 - 19.46709669856150000 0.06534035733235650

SR2 HR Center 0.25338041676837300 - 4.65707511714485000 0.01636835759826590SR2 HR Chord Center 0.25343699791525600 - 4.65424362287551000 0.01635910778298700SR2 HR Center of Mass 0.25443596781021600 - 4.60425387059867000 0.01619580332356480

SR3 HR Center - 0.10019572229664500 - 15.71831709528840000 0.05206098673976600SR3 HR Chord Center - 0.10018936880116400 - 15.71799932705380000 0.05205994867886630SR3 HR Center of Mass - 0.10118833869612400 - 15.76798907933070000 0.05222325313828850

F(X,Y,Z) X Y Z3026.50720000000000000 - 0.09390876010000000 0.000000000000000003026.50720000000000000 - 0.09390876010000000 0.000000000000000003026.58220000000000000 - 0.09390876010000000 0.00000000000000000

0.06724972300000000 3023.22190000000000000 0.000000000000000000.06072497230000000 3023.22189000000000000 0.000000000000000000.06072497230000000 3023.29689000000000000 0.00000000000000000

0.00000000000000000 0.00000000000000000 0.000000000000000000.00000000000000000 0.00000000000000000 0.000000000000000000.02828427000000000 0.02828427000000000 0.00000000000000000

26.50720079000000000 - 0.09390876000000000 0.0000000000000000026.50720439000000000 - 0.09390876000000000 0.0000000000000000026.43220439000000000 - 0.09390876000000000 0.00000000000000000

0.06072497000000000 23.22189738000000000 0.000000000000000000.06072497000000000 23.22190098000000000 0.000000000000000000.06072497000000000 23.14690098000000000 0.00000000000000000

- 19.46123288000000000 0.21377980000000000 0.00000000000000000- 19.46120738000000000 0.21377925000000000 0.00000000000000000- 19.51120721000000000 0.21364765000000000 0.00000000000000000

- 4.70068120000000000 0.25262878000000000 0.00000000000000000- 4.69784943000000000 0.25267014000000000 0.00000000000000000- 4.64785476000000000 0.25340040000000000 0.00000000000000000

- 15.76372140000000000 - 0.04148993000000000 0.00000000000000000- 15.76340359000000000 - 0.04148529000000000 0.00000000000000000- 15.81339825000000000 - 0.04221555000000000 0.00000000000000000

0.13541083000000000 - 19.41723194000000000 0.000000000000000000.13541104000000000 - 19.41720645000000000 0.000000000000000000.13501125000000000 - 19.46720485000000000 0.00000000000000000

0.25343357000000000 - 4.65710099000000000 0.000000000000000000.25349012000000000 - 4.65426948000000000 0.000000000000000000.25448854000000000 - 4.60427945000000000 0.00000000000000000

- 0.10002163000000000 - 15.71840442000000000 0.00000000000000000- 0.10001528000000000 - 15.71808665000000000 0.00000000000000000- 0.10101370000000000 - 15.76807668000000000 0.00000000000000000

↑麻生先生データ

Center room coordinate 　　　 　　 　　 　　 　 Optical coordinate (by (Asou)

120123 　 VAC (UI)

19

LCGT Vacuum System

120123 　 VAC (UI)

20

LCGT Vacuum System

** Drawing of 3D-CAD pictures

Apr 2014

Apr 2014Apr 2014 to Aug 2014

Sep 2014

Oct 2014 to Mar 2015

1) manufacturing 478 of tubes; from Apr 2011 to Mar 20132) manufacturing chambers; from Sep 2012 to Mar 20143) installing chambers in X end; Apr 2014 4) installing tubes in X arm; from Apr 2014 to Aug 20145) installing chambers in Center Room; Sep 20143) installing tubes in Y arm; from Oct 2014 to Mar 20155) installing chambers in Y end; Mar 2015X arm pump down; Sep 2014 Y arm pump down; Mar 2015

21

120123 　 VAC (YS)LCGT Vacuum System

expected schedule for installing (1)

3. Schedule

ETMYA

ITMY

ETMXAITMX

BSPRM PR3 PR2

SRM

SR3

SR2

PD

MCF

MC

3000 m

iLCGT iLCGT

MMT

ETMYB

ETMXB

carrying tubes from MOZUMI pithead

22

120123 　 VAC (YS)LCGT Vacuum System

expected schedule for installing (2)

3. Schedule 1) manufacturing 478 of tubes; from Apr 2011 to Mar 20132) manufacturing chambers; from Sep 2012 to Mar 20143) installing chambers in X and Y ends; Apr 2014 4) carrying tubes and lay on the supports;

from Apr 2014 to Jun 20145) jointing tubes and pump down in X and Y arm

from Jul 2014 to Mar 20156) installing chambers in Center Room; Jul 2014

Apr 2014

Apr 2014Jul 2014 to Mar 2015

Jul 2014

carrying tubes from ATOTSU pithead

ETMYA

ITMY

ETMXAITMX

BSPRM PR3 PR2

SRM

SR3

SR2

PD

MCF

MC

3000 m

iLCGT iLCGT

MMT

ETMYB

ETMXB

Jul 2014 to Mar 2015

Apr 2014

** recovery “without breaking arm-vacuum”BA gauge failure: grid contamination, filament breakdownfeedthrough erosion; high voltage feedthrough of ion pumppower supply/controller erosion; ion pump, turbo molecular pumpdurability for humidity is being examined (50°C-98%, 7 cycle of 8h-operation/98h-off).

** recovery “by re-pumping an arm”window (view port) break downcrack and erosion in bellow jointmetal gasket erosion

** safety “by closing gate valves (large dia,)”electric-power shut downanomalous pressure rise ETMXITMX 3000 m

expected pump-down scheme (a 3-km arm)to 1 Pa >> few days by dry-pumpto 10-6 Pa >> 50 hours by TMPto 10-7 Pa >> 500 hours by IP

(based on the ougassing rate in test tubes)

120123 　 VAC (YS)

IP TMP

FL PDRY P

23

LCGT Vacuum System

vacuum component failure and leakage

4. Risk management

** “surface passivation process” of stainless steel prior to installation is planned by applying electro- polishing, and then followed by pre-baking treatment.

** “outgassing rate” of the order of 10-8 Pa m3 m-2 s-1, or lower is performed in J-PARC.

Appendix: outgassing data measured for technical surface

0.1 1 10 1001E-09

1E-08

1E-07

1E-06

1E-05

1E-04 Ti (passivated): ID 164 X L 4782SUS316 (ECB): ID 600 X L 9990SUS316 (EP/pre-baked): ID 131-104 X L 6399Cu (PR-EF lining, 2nd pump.): ID 560 X L 3000alumina ceramic: ID 246-188 X L 3540

pumping time [hours]

outgassin

g rate [P

a m3 s-1 m-2]

120123 　 VAC (YS)

24

LCGT Vacuum System