Today, we measured vibration of six cryocoolers using cryo-accerelometer installed on the cryostat inner shield.
This result(graph) shows the peaks of 30-40 Hz are very big(~1.0e-07 m/rtHz).
It amplitude is the same of Dan Chen's result (measured at Toshiba Keihin Office).
And result of Trillium-Speedmeter put near the Cryostat shows similar to cryoacc's.
(Attention, result of cryocoolers on of cryoacc is too noisy so I cannot measure the vibration on 1-10 Hz accurately.)
27th of Feb (Mon)
all cryocoolers (four cryocoolers for cryostat and two cryocoolers for cryoduct) started to work
(16:50 JST). We measured vibration before and after start of cooling. We observed cryocooler generates
vibration. Details are being analyzed.
Photo
https://photos.google.com/share/AF1QipPA0p75Ew1F-fx_iPahKElRBCBC77ZChmvsQxCpJReiasF8rD2Fk_0WNQ90zjO2GA?key=bjZkcTUyTjBXYTBOVUstNlBpeDlIb0JqVVA2dEJn
28th of Feb (Tue) - 3rd of March (Fri) : Vibration measurement and adjustment to compensate drift by cooling
4th of Feb (Sat) Kazuhiro adjusted Luca's accelerometer (vertical direction) to compensate drift by cooling.