1. E. Majorana (INFN – Rome) ELiTES 3 rd General Meeting Hongo Campus – Tokyo – 9-10 Feb., 2015 Cryogenic platform with vertical suspension: a practical approach

2. A. Hagiwara UPDATE OF CRYOGENIC PAYLOAD DESIGN AND PREPARATION OF PROTOTYPE TESTS (K. YAMAMOTO)

3. Cryogenics tech. noise  possible ancillary passive attenuation at the level of cryostat shield easy to conceive  need of further attenuation through PF blades Vertical TN  Horizontal Schematics (T. Sekiguchi, D. Chen): IM is the main steering body of the mirror. According to the models IM is affected by two main sources of noise FROM THE SIDE FROM THE TOP F o ~ 0.3 Hz. Q ~ 200 F o ~ 0.3 Hz. Q ~ 200

4. E. Hennes, ELiTES 2 nd General meeting GAS behavior VS T (H. Hennes et al. FEA and tests with ): Ext Inj Bench of AdV (NIKHEF) FEA VS real case checked  ~ OK THERMOELASTIC OF THE BLADES THERMAL EXPANSION OF THE PLATE T VERTICAL POSITION DRIVEN BY FREQUENCY DRIVEN BY WORKING POINT UNCHANGED VERTICAL POSITION DRIVEN BY

5. WHAT COULD BE DONE (YESTERDAY) (H. Hennes et al. FEA and tests with ):

6. By choosing proper materials one can tune, is it really feasible ? Probably yes, but through an extensive study, for KAGRA cryogenic prototype it seems late the advantage: -scalable effect, small facility can be used criticality: -50 grams accuracy in tuning is required, even assuming a perfect result ( ) for a small prototype would it be achievable once the one the real filter 1:1 is built ? A conservative approach: Meanwhile the tests on materials go on on small-scale facilities a direct test, using CuBe can be conducted on 1:1 cryogenic platform Cryogenic KAGRA has to ensure performance at low temperature.

7. Any position sensor 80 kg Termometer Light rigid shaft (ex,G10, Vespel®) flange knob Issues: check thermal isolation from 20 K environment by checking first min operation T of the Gauge. Check shield pass through versus cryostat design. Check cooling time issues. ~ 200 kg cooling. In 3 runs we measure it; LN2 cryostat available? dummy payload RoomT 80 kg 20 K 80 kg Needed force Expected m*= 5-10 kg E. Hennes, GWADW 2014 20 K Motor?

8. Given the tight schedule a commercial product is preferable The driller used by Curiosity has a cryogenic load cell working at low T: commercial suitable devices do exist but they reach at most 190 K Care in the experiment design

9. Any position sensor 80 kg +m* Extra –load saturates the mechanical range In practice the extra mass can be placed on the keystone or on the GAS (not recommended in the real installation). If IM is composed by two parts (K. Yamamoto et Al.), the mass should be placed on the upper one. It is important to start soon the experiment and platform design because it impacts also on the IM upper stage design. Room T, filter saturated, the suspension is set in position using the top-stage motor 20 K GAS in range at low temperature with 10 g accuracy thanks to the extra-load Cryogenic KAGRA has to ensure performance at low temperature dummy payload check

10. fp = 0.9 Hz 2 wires capacitive actuator electrode Fiber bundle sensor exchange gas / evacuated A suitable design will be developed according to: -PT impulse harmonics VS system modes -Check of VFC control BW (f BW < 6-8 Hz max) -Design of capacitive actuator Critical issues - Actual recoil losses (to be studied first with dummy dielectric rods) - Control performance stability few-days runs - Environmental stability 5 kg clamp E. Majorana ~ 10Hz Seismic (VFC) 1 st ELiTES meeting Oct. 2012, Tokyo. Example of practical experiments in the context of ELiTES collaborative effort Ext flange First stage shield 40K second stage chamber 8 K 3 Susp wires 2 Susp wires sensor Massive block

11. Ext flange First stage shield 40K second stage chamber 8 K 3 Susp wires 2 Susp wires sensor Massive block Dan Chen measurement in Rome, 2013, 2014