Conveners
Cryogenics workshop: CE and Voyager
- Kazuhiro Yamamoto (Faculty of Science, University of Toyama)
Cryogenics workshop: ET
- Paola Puppo (ROMA1)
Cryogenics workshop: KAGRA
- Kazuhiro Yamamoto (Faculty of Science, University of Toyama)
Cryogenics workshop: R&D projects
- Paola Puppo (ROMA1)
Cosmic Explorer is a 40 km long third generation gravitational wave detector envisaged to be realized in two stages. The first stage (CE1) will use the room temperature fused silica and 1 $\mu$m laser technology of LIGO A+. The second stage (CE2) will either continue to use this technology or will use the cryogenic silicon and 2 $\mu$m laser technology of LIGO Voyager. In this talk, we will...
Cosmic Explorer requires an unprecedented level of isolation from the ground and from thermal noise. If we want to reach the design sensitivity of $10\rm^{-23} Hz^{-1/2}$ down to 5Hz, scaling up the LIGO A+ technology might not be enough, and new designs, as well as new technologies, need to be investigated.
One possibility is Cosmic Explorer 2, or CE2, which either uses a $\rm 1\mu m$ laser...
Radiative cooling is a contact-free cooling technique that allows cooling of 100kg scale mirrors to cryogenic temperatures. However, future optomechanical applications require lightweight mirrors, for which radiative cooling is inefficient. In this talk, I will present optical refrigeration as a low-vibration cooling method for a phase-sensitive optomechanical amplifier, proposed to improve...
We present our theoretical calculations of the effective emissivity for the LIGO Voyager test masses. Once Si at 123 K is a semi-transparent material, the emissivity depends on the mean thickness and the absorption, both calculation is also shown in this presentation. Finally, we present our recent resuts using internal reflexions for the mean thickness calculations.
We review the current effort for driving the design of the Cryoneic and vacuum system foer the Einstein Telescope Project.
The scientific target of cooling-down test mass payloads of ET without affecting the capability of reaching very high sensitivity in the low frequency range is often assessed as achievable. Indeed, relevant developments have still to be pursued with the perspective of a reasonable technical design. Moreover, the overall design of cryostats and its technical facets are interlaced with several...
Placeholder
The low-frequency interferometer in the Einstein Telescope (ET-LF) shall be operated at test mass temperatures of 10 K to 20 K. Motivated by the potential of using superfluid helium (He-II) for cooling the test masses, we derive a general cooling concept for the ET-LF cryostats. This concept is based on a helium refrigerator at each ET corner station, providing cooling ...
Condensation on the surface of the main mirror and the viewport for oplev of the radiation shield is a serious problem at the cryogenic gravitational wave telescopes, KAGRA. In order to find a way to cool the main mirror down to the required temperature (~20 K) while preventing condensation, cryo-group of KAGRA conducted a cooling experiment of the main mirror using the a KAGRA cryostat.
In...
The cryogenic mirror is a direct way to reduce thermal noise. To cool the mirror at cryogenic temperature, the conductive cooling with heat links is necessary, however, they become a new path of vibration transfer simultaneously. We have newly developed a vibration isolation system for heat links and successfully reduced vibration transfer. Details of design and performance tests will be reported.
Operating gravitational-wave detectors at cryogenic temperature has several technical difficulties. One known difficulty is an initial alignment of the interferometer. We have observed 150 urad of pitch inclination drift of mirrors during cooling, which is larger than range of coil-magnet actuators of cryogenic payload. During bKAGRA Phase 1 operation, the first cryogenic operation of KAGRA,...
In the future cryogenic gravitational-wave detectors such as the ET and LIGO Voyager, a molecular layer formed on the cryogenic mirror surface can become one of the problems due to its optical loss. We theoretically estimated the optical loss induced by the molecular layer and revealed that the optical absorption induced by the molecular layer. In addition, we developed 10 K folded optical...
To reduce thermal noise and improve the sensitivity at low frequency, future gravitational wave detectors will use cryogenic mirrors. Cryogenically cooled mirrors present a number of extraordinary challenges, one being on the cryogenic vacuum system hosting the cold mirrors.
At cryogenic temperature, gases composing the residual vacuum will cryosorb and form a contaminant ice layer on the...
One of the key enabling technologies in the third generation laser-interferometer GW detectors is the cryogenic system required for cooling the main optics to 10 – 20K. Accounting for the extreme sensitivity that is targeted, it is of paramount importance that the cryogenic cooling under continuous operation is essentially vibration free. Joule-Thomson cryocoolers using sorption compressors...
