My work in December1田中宏樹

Suspension of fiber

• We suspended the sapphire fiber to get higher Q.• wire1(W)• heat link(Cu)• fiber • Laser

• PD • wire2(W)

Setup(Suspension)

Accident

• The other head was broken!

Result1(With bottom head, Cu cramp)

• 5K,86Hz…Q=9.7×(In Rome, Q=• 5K,1223Hz…Q=1.9×(In Rome, Q=5×)• 300K,86Hz…Q=5000(In Rome, Q=5600)• 300K,1223Hz…No peak(In Rome, Q=5×)

Result2(Without bottom head, Al5056 cramp)

• 5K,290Hz…Q＝ 2.3ו 5K,1810Hz…Q=1.2ו 10K,290Hz…Q=1.8ו 10K,1810Hz…Q=1.1ו 20K,290Hz…Q=1.7ו 20K,1810Hz…Q=1.8ו 300K,290Hz…Q=1.4ו 300K,1810Hz…Q=1.5×

Result3(Without bottom head, suspended)

• 5K,1st mode…Q=• 300K,1st mode…Q=1.3ו 300K,2nd mode…Q=3.8ו This case we used Cu cramp.

Results

0 50 100 150 200 250 300 3501000

10000

100000

1000000

10000000

With bottom head, Cu crampWithout bottom head, Al crampWithout bottom head, Cu suspensionDan Chen in Rome

温度 (K)

Q値

Suspension of the sapphire mass

Displacement sensor

LabVIEW

Future work

• Measurement of fiberA(monolithic)• HCB to the broken head• Annealing of sapphire fiber