Type-C (TAMA) suspension

Type-C suspension is a relatively small double pendulum with intermediate mass passively damped by eddy current damping.
Some of the type-C suspensions which are used in KAGRA were once used for TAMA300, originally designed by K. Arai in 1990s.
So type-C suspension is sometimes called as TAMA-type suspension.

• Note by K. Arai(2014)

Type-C can be roughly divided into 2 types.
PO (Pick-off) type suspends the mirror with the thickness of about 3cm.
TM (test mass) type suspends the mirror with the thickness of about 6cm.
Main differences are in the intermediate mass and frame design.

iKAGRA

In 2017, 5 type-C suspensions were installed in iKAGRA.
In the final iKAGRA configuration, 7 mirrors were suspended and 6 of them were Type-C.

Mode Cleaner suspensions

The thickness of the mode cleaner mirrors are about 3cm. So the suspensions for the MC mirrors are PO-type. Following the suggestion by K. Arai, *Design change for new suspensions(by K. Arai) some modification, mainly in the Main frame has been done by H. Ishizaki.

Mode cleaner suspensions will be used for long term even after the iKAGRA. Nakano-san installed MC_i, MC_e, and MC_o. The thickness of the MC mirrors are about 3cm. This type of the is called as PO(pick-off).

Temporary mirrors

The others were TM(test mass) or RM type; ETMX, ETMY with the mirror thickness of about 6cm. The last one is coming from CLIO, the size of the BS mirror was 4cm in thickness and 15cm in diameter.

Work log about 2 iKAGRA ETMs is here.

• ETM Transfer function
• long term drift

bKAGRA

• Two suspensions used at the X/Y ends, are used as IMMT1 and IMMT2 for bKAGRA.

  Memo by Yamamoto-san

• IMMT Preparation

Drawings

• OSEM

• Drawings

• Magnet and standoff fixture jig

• IMC_suspension