Download f2f 140731

Vibrtion isolation system
for KAGRA
Ryutaro Takahashi
(National Astronomical Observatory of Japan)
The 10th face to face meeting
Toyama University, 31 July - 2 August, 2014
Contents
1.
Configuration
2.
Installation Schedule
3.
R&D Status
• Test of the payload prototype
• Test of the bottom filter prototype
4.
Summary
1. Configuration
Type-A: for cryogenic mirrors
Type-B: for room temperature mirrors
Type-Bp: simpler Type-B
Type-C: for small optics
Seismic
Attenuation
System
SAS
(Type-A/B)
Top Filter (TF)
Pre-isolator
(PI)
Filter chain
Inverted Pendulum (IP)
Standard Filter (SF)
Filter1~3 in Type-A
Filter1 in Type-B
Bottom Filter (BF)
Intermediate Mass (IM)
Intermediate Recoil Mass (IRM)
Payload
(PAY)
Test Mass (TM)
Recoil Mass (RM)
Type-B
Type-A
BS
Type-Bp
PR2, PR3
Top Filter
IXA, EXA,
IYA, EYA
Type-C
MCF, MCE,
IFI, IMM
iKAGRA
Inverted Pendulum
Standard Filter
Bottom Filter
Payload
Bread Board
Stack
Base Plate
bKAGRA
IXV, EXV,
IYV, EYV
Cryo
-Payload
SRM, SR2,
SR3
PRM
Type-A
TF
IP
SF
BF
CRYPAY
Type-B
TF
IP
SF
BF
PAY
BB
Outer frame
Type-Bp
SF
BF
PAY
BB
BP
Type-C
PAY
BB
Stack
BP
MCe
Sensors & Actuators (Pre-isolator)
Fishing rod
•Additional function to adjust vertical DC position for the
standard filters and the bottom filters.
•Maraing plate with 0.3mm in thickness is necessary.
(standard filter)
stepping motor
Sensors & Actuators (Type-B/Bp Payload)
Sensors & Actuators (Type-C)
PIC(V)
2. Installation Schedule
for bKAGRA
Flow of assembly
3. R&D Status
•Test of the pre-isolaor prototype was
finished in Kashiwa (ICRR).
•Test of the payload prototype is under
going in Mitaka (NAOJ).
•Test of the bottom filter prototype was
finished in Mitaka (NAOJ-ATC)
•Full prototype test using TAMA300 will be
started.
Test of the payload prototype
•Main parts were assembled once to confirm
the dimensions each other.
•Transfer functions of TM-RM system was
measured.
•Position sensors are tested and improved.
Test mass (TM) and Recoil mass (RM)
IM
60 cm
RM
60 cm
Intermediate mass (IM) was fixed to a frame, suspending:
• Test mass (mTM = 10.7 kg) by Tungsten wires (d = 0.2 mm)
TM
• Recoil mass (mRM = 20.4 kg) by Tungsten wires (d = 0.6 mm)
Control the TM by 4 Optical Sensor and Electro-Magnetic actuators
(OSEMs).
OSEMs were diagonalized to the virtual directios (x, pitch, yaw)
Transfer function of the TM-RM
by J. V. van Heijningen
Calibration of OSEM (#9 as an example)
For three different position of the flag along the X direction
(0 and ± 400 μm), three different calibration curves were
generated by moving the flag along the Y direction.
Y: displacement during operation
X: set during alignment
LED
PD
Y
X
Calibration factor: -6.737 V/mm.
Displacement range (linear regime along Y): 1 mm.
Alignment range (along X): ± 400 μm with a ±3.8%
error.
by F. E. Pena Arellano
Sensitivity of OSEM (preliminary)
by F. E. Pena Arellano
Test of the bottom filter prototype
Function: final vertical filter
Dimension: f730 x 272h
Weight: 99kg
Blades: Marasing steel x3
Load: 48.6kg
Aimed frequency: 0.4Hz
One vertical position sensor: LVDT
One vertical actuator: voice coil
Attitude control: two motors for pitch,
one motor for yaw
Maraging steel for GAS blade
Aging process
•Daido Steel MAS-1: 480℃, 4h
•Aubert & Duval Marval 18: 435℃, 100h
Measurement of resonant frequencies
Optimum load [kg]
Working height [mm]
Frequency [Hz]
G&M(Marval 18)
47.6
64.5
0.4
ATC(MAS-1)
50.2
(5% up)
64.5
0.7→0.3
4. Summary
 Four kinds of vibration isolation system are used in
KAGRA. Installation will be started in Octover.
 The OSEMs on RM were diagonalized and the transfer
functions of TM-RM system were measured.
 The new optics in the OSEM offered 4% error in the
alignment range of 0.8mm.
 The production process of the GAS blade was
estblished with new maraging steel and shorter aging
time.