Overview of iLCGT & bLCGT Kazuaki Kuroda LCGT Collaboration F2f meeting 27 September, 2010

Introduction This meeting is the first kick-off meeting of LCGT Objective of this f2f meeting – Confirmation of policy and execution – Recognition of collaborators and mutual understanding – Sharing information & ideas for construction – Coordinating activities of sub-working groups Overview of iLCGT & bLCGT – Objective, Design, Organization, R&D etc.

LCGT has been funded Japanese government bravely decided to construct LCGT (June, 2010) – Due to its significance of fundamental science with its unique features of underground and cryogenics It is anticipated to firstly detect gravitational wave – Its uniqueness will promise the first discovery and may lead to the basis of the third generation detector It is also expected to play a key role in the worldwide GW network – Adv. LIGO and Adv. Virgo have similar sensitivity

１） Increase the large baseline length （ 20 ms time flight among North America, Europe and Asia ） ２） Widen the sensitivity pattern The role of ＬＣＧＴ in the world-wide network Adding LCGT to L/H-L/L-Virgo, the whole sky coverage is realized 33% coverage100% coverage By global Schutz(Fujihara seminar, May 2009)

Sensitivity of LCGT and future improvement This figure will be revised soon by new design

Location of LCGT LCGT is planed to be built underground at Kamioka, where the prototype CLIO detector is placed.

The Characteristic of LCGT The interferometer of LCGT belongs to the first generation detector – operated at underground environment – utilizing cryogenics Cryogenic leaves the optical design of LCGT rather conservative – Traditional size of the beam (no need of larger optics) – Less thermal lens effect (no need of TCS system on main mirror) – Less serious optical instability No new advanced technology for cryogenic mirror system – Traditional cryogenic technique available – However, mirror exposed to room temperature wall

Optical design of LCGT (main part) Beam radius 3cm These main parameters determine backbone of optical configuration and reachable sensitivity

Plans of optical configuration ： introduction of v-RSE

Achieved results by TAMA and CLIO TAMA in 2008 (improved after installation of SAS) 300 m arm length CLIO at cryo temperature, 2010/3/7 100 m arm length CLIO limit by room temperature LIGO 4 km LCGT design, 3 km

Schedule of LCGT coincides with the original GWIC roadmap Edited in November, 2009 Construction scheduleschedule

Initial and baseline LCGT Initial LCGT without cryogenic mirror will be operated by October, 2014, in order to show an engineering result (First Step that should be fulfilled) The initial LCGT forms the main part of Baseline LCGT (except recycling and cryogenics) Synthesized silica for the initial LCGT mirror and sapphire for the baseline LCGT Since cryostats cannot be physically installed after the initial LCGT, the main bodies of cryostats are installed at the first stage Tall anti-vibration system may be installed in the first phase

Support from overseas projects Requests to LIGO for introducing its advanced techniques and manpower – Negotiation ongoing to make an Attachment under existing academic research MOU (LCGT requests several items) Requests to Virgo for its advanced techniques and manpower – Start to make MOU for technical research collaboration Request to GEO for its advanced techniques and manpower – Preparing for making MOU for stronger collaboration Request to AIGO for its advanced techniques and manpower – Seeking possible research collaboration