Sapphire Q measurement meeting

2023 August 24 13:00-14:00

Aso, Dan, KYamamoto, RTakahashi, Aso, Suzuki, Miyoki 

(1)Stocks of bulks with ears
Two pieces were found at NAOJ. Marc would like to measure both of them. We expect that he will measure at least 
one of them before we prepare our apparatus.

(2)Offsite Q measurement
Yesterday and today, M. Yamamoto and Y. Sato (U Toyama), K. Komori (U Tokyo), K. Tanaka (ICRR) are measuring Q of 
ETMX (about 30K). We are afraid that AR side is covered by frost.

(4)Suzuki-san's  suggestion
(1)Short meeting (1 hour) -> At least this meeting ended within one hour. 
(2)We also take care of Q of sapphire fibers in this meeting (later).


(4)Mirror Q measurement (Yamada and Suzuki)

(a)Clamp : Wire inclination is 10 degree to avoid any bending of wire.

(b)Wire breakers
Other wire breakers, for example breakers on bottom side or smaller breaker on 
lower side -> RTakahashi pointed out smaller breakers were broken or dropped if he 
remember correclty.
A/I : Yamada asks Hirata-san details later.

Long breakers (2 pieces) or short breakers (4 pieces) ? 
-> Shorter ones to avoid effect on Q.
 
Distance between wires : According to N. Ohishi's master thesis (https://granite.phys.s.u-tokyo.ac.jp/theses/Ohishi-m.pdf),
the best distance between 2 loop wires for Q measurement is one third of mirror thicknes.
It implies that wires must be in slits of sapphire ears. However, the wire breaker 
could be larger (and Q might be lower).
A/I : Yamada and Suzuki check the size of breakers for wires in slits. 

Material wire breaker is stainless. Sapphire breaker lead time is long.

(c)Glue
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.

(d)Earthquake stopper and Actuator
Yamada and Suzuki's idea is similar to HCB box. In HCB box, soft large parts touch HR
and screw touch AR to fix the mirror. In Q measurement, actuator electrode 
is on AR surface.To avoid collision of AR surface and electrode, soft large part is 
necessary on AR side. So, screw is on HR side. Is it OK ? Otherwise, screw touch on 
chamfer ?
-> D. Chen suggests the electrode on HR side which has hole for laser beam. 
Large soft part is on HR side and screw is on AR side as HCB box. -> We approve.
A/I : Yamada and Suzuki revise Earthquake stopper.

Again, according to N. Ohishi's master thesis, she used two metal plate (not 
comb like !) as electrode of actuator. Laser beam is in gap between two metal plates.
Actullay it makes sense because the 
bulk is large. The torelance of gap between electrode and bulk is modest.
-> Yamada and Suzuki consider details of actuator.

(e)Installation 
Misumi frame, lab jack (it can work with heavy load), and roters (they can work with
heavy load).

(5)Budget : Miyoki requests quoation for discussion.

Next meeting will be on the week of 18th of September. Kazuhiro will circulate doodle later.

A/I (all for Yamada and Suzuki)
(a)Asking Hirata-san details of wire breakers in Type B and Bp as reference later.
(b)Checking the size of breakers for wires in slits. 
(c)Revising or consideration about design of actuator and earthquake stopper.
(d)Quotation