Sapphire Q measurement meeting

2023 September 21st (Thu) 16:30-18:00

TYamada, R. Bajpai, Aso, KYamamoto, RTakahashi, Aso, Suzuki, Komori 

(1)Offsite Q measurement
Q-value measurement of ITMY under 88K by M. Yamamoto (Toyama), Nakano (Caltech), K.Tanaka (ICRR).
It was on the order of 10^6 !
(at 250K, on the order of 10^4. ETMX Q around 80K was on the order of 10^5).
https://klog.icrr.u-tokyo.ac.jp/osl/?r=26679


(2)Mirror Q measurement (Yamada and Suzuki)

(a)Improvement of EQS ->Large teflon parts push HR and screws with teflon push AR screw as HCB box.
50mm hole for laser beam.
 
(b)Electrode design
4 simple electrodes.

(c)Gluing system
We reuse HCB box and some parts fabrication is necessary.
We use optical table. M6 screw holes (25mm inteval) are position reference. The pin in these holes contact 
HCB box and the box position is decided.

The designs of the parts to handle breakers themselves are being considered. Only x-stage is necessary to 
push breakers on mirror barrel surface because the position of the stage is decided precisely (M6 holes). 
A/I : Yamada asks Hirata-san details of breakres later.　

Sapphire spare mirror and HCB box can be outside clean booth ?
-> Spare mirror is OK. But we are not sure HCB box. 
-> A/I Kazuhiro asks Ushiba-kun HCB box stocks and which can be used. 

(d)Ear's slit

Two choises
(i)We do not use ear's slit (wires is near AR or HR). Squeezed (not vertical) wires. Two breakers for each wire.
(ii)We use ear's slit. Wires are almost along vertical direction. Four breakers are necessary for each wire. Revision 
of clamp part is necessary.
-> We selected (ii). 

(e) Quotation is sent by 6th October (Fri)

(f)Glue
Discussion is in progress. EP-30 in Type B and Bp.

What we discussed in the previous meeting. 
Glue must be removed. What kinds of glue ? Are In or Ga feasible (this glue need 
not to support heavy load) (Dan's suggestions) ? -> We continue discussion.



(3)Sapphire fiber Q measurement (Bajpai)

Support : 2 Cu plates, double suspension, heatlink between 2 Cu plated. 
Short and long fibers can be measured.
If vibration is large, damper (magnets) is installed.
Corn shape clamp is used even for square nail heads.
 
Misumi Al frame could be deformed. Stainless could be adopted because we do not expect frame as 
heat transfer. 
This frame is on optical table connected to cold head.

Laser displacement sensor is used. 

Electrode must be designed. 
Many electrodes are useful when we want to excite many modes. 
High voltage supply in KEK must be checked (specification and whether they work).

Thermometer calibration cooling (thermometer on bottom side of fiber) is planned.
Details of heater must be taken care of.

Chen's thesis is a reference.

Budget : Not so many ?

Next meeting will be on the week of 9th of October. Kazuhiro will circulate doodle later.

A/I
(a)Yamada asks Hirata-san details of breakres later. (wire breakers in Type B and Bp as reference later).
(b)Kazuhiro asks Ushiba-kun HCB box stocks and which can be used.