GU Physics DokuWiki et_update_2017

et_update_2017:6sept2017

2017-09-08T10:44:44+01:00

* Seismic noise: include long term variations. Previous short term studies: Recent long term measurement, preliminary, Sos Enattos, 480 days: Further info: and

et_update_2017:abandoning-xylophone

2017-09-08T09:41:44+01:00

(Stefan, Benno, Bryan, Andrew, Sean, Marina) Motivation Why xylophone * Concept proposed to avoid conflict between high frequency and low frequency design compromises (high/low optical power, thermal, quantum noise, etc) Question: Do we still need the xylophone?

et_update_2017:all-sus-modes

2017-09-07T11:36:14+01:00

See materials and suspension page for comments

et_update_2017:coatings-update

2017-09-08T14:34:22+01:00

Set of slides can be found [here] Open questions / other approaches: * Can we get aSi-based coatings <1ppm absorption? * 120 K operation? Some more work needed. Silica loss potentially lower than at 10 / 20 K (depending on annealing state). Cooling by radiation, less limited by heat extraction. Less TN benefit from cooling.

et_update_2017:conclusions_and_observations_of_the_meeting

2019-09-11T15:07:15+01:00

Suggestions for discussion in plenum * Required software tools for further modelling * GWINC? * Logbook? * Should investigate single L? * Should investigate single broadband 120K design? (simpler , realistic on shorter times, while still good LF frequency potnetial). How much time and money can be saved if we go for single 120K detector. * Would is needed to get onto the ESFRI roadmap? technical design? Budget? Sensitivity? decision xylophone vs single detector? * Step 1) conso…

et_update_2017:et_telecons

2019-06-12T16:13:51+01:00

We will use team speak for the telecons together with slides posted on the wiki. Teamspeak details are * server: zam.mit.edu * password: la$er * channel: ET Future telecons Telecons are usually held on every second Wednesday of a month, 4pm-5pm CET, 3pm-4pm UK time.

et_update_2017:large_beams

2017-12-06T12:40:35+01:00

Large beam size Material * Brief introduction and review of the scaling of alignment noise coupling with arm cavity beam size, Andreas Freise 06.12.2017:

et_update_2017:lg33

2017-09-07T17:58:00+01:00

Published articles Simulations of long cavities Related literature since the ET design study, focusing on simulation with realistic mirrors (not about the table top experiments): * Higher order Laguerre-Gauss mode degeneracy in realistic, high finesse cavities by C. Bond et al, 2011 link * Effects of mirror aberrations on Laguerre-Gaussian beams in interferometric gravitational-wave detectors by T. Hong, 2011 link * Reduction of higher order mode generation in large scale gravitational …

et_update_2017:optimum-length

2017-09-08T09:02:33+01:00

Introduction Different properties of ET scale differently depending on the length - some even in opposite directions - so there is in principle an optimum length. Apart from the obvious ones like noise and sensitivity, the length also has a big impact on the cost. Longer arms need bigger beams in order to avoid having highly divergent beams, too. This is an attempt to list the constraints on length to allow us to arrive at the optimum.

et_update_2017:pis

2017-10-06T11:57:07+01:00

home This page collects work on tasks related to Parametric Instabilities and Arm Cavity Alignment Instabilities, and is more broadly to the optical design of the arm cavities. General considerations: * starting with ET HF but consider a Voyager-like (no Xylophone, 120k) alternative for comaprison

et_update_2017:quantum_noise_of_et_lf

2017-10-06T11:55:00+01:00

ET Low-Frequency Quantum Noise (Daniela, Jennifer, Haixing, Omar, Peter, Vaishali, Sebastian) Summary & Next Steps * keeping ET-LF+HF, we have the option of increasing the low-frequency sensitivity significantly by using dynamic detuning or unstable filters * GWINC model to be finished * what would be the requirements for such a filter? * is background collection / sensitivity calibration an issue?

et_update_2017:science-case-for-2hz

2017-10-04T20:38:13+01:00

main selling points for as low frequencies as possible: * early warning with sky localization for EM followup thanks to early SNR buildup. ~1000s-10ks * IMBHs/IMRIs with higher total masses (>1000Msun) and up to high redshifts -> cosmic history of SMBH seeds * Long inspiral gives highly improved CBC parameter estimation even with just small SNR gains, breaking degeneracies with precession and higher modes, constraining ellipticity before it is completely radiated away. -> formation channe…

et_update_2017:site-geology

2017-09-06T16:12:59+01:00

Currently, we have punctual measurement at different sites following local initiatives. Using a model, geological maps, population densities, distance to the seas,... would it possible to have a map of Europe with the sites with the lowest seismic noise (or another figure of merits). Of course, that would have be confirmed with local measurement.

et_update_2017:start

2017-12-06T12:36:41+01:00

Einstein Telescope Design Update Workshop at Glasgow, September 2017 Slides From Plenary Presentations * Karsten Danzmann: * David Shoemaker: aLIGO experience in the context of ET * Sheila Rowan: [Worldwide co-ordination towards a 3G network] * Jo van der Brand: * Salvatore Vitale: [3G Science overview] * Michele Punturo: Overview of the ET design and next steps on the ET roadmap * Harald Lueck: * Stefan Hild: [Slides for starting of discussion] * Humboldt Foundation (not …

et_update_2017:substrates-update

2017-09-09T09:31:56+01:00

discussed together with suspensions. See https://gilsay.physics.gla.ac.uk/dokuwiki/doku.php?id=et_update_2017:sus-materials-update Silicon still prime candidate for cryo @ 20K and 120 K. Technically doable (45 cm size, purity), but how to obtain it. Silicon TPA ok for high power operation @ 1550 nm.

et_update_2017:sus-materials-update

2017-09-15T10:58:51+01:00

Different configurations 10-20K 120K (Voyager style) 300K (ET-HF) Material Silicon Sapphire Silicon Silica Intra cavity power 18kW 18kW 3MW 3MW Mass 200kg 200kg 200kg 200kg Wavelength 1.5-2um 1064nm 1.5-2um 1064nm Remarks Less progress in silicon research than expected before, costly and not sure if industry will supply it Absorption challenging (KAGRA issues) Pro better for cryogenic Can use 1064 with sapphire Cheaper and easier from cryo standpoi…

et_update_2017:tcs

2017-09-08T11:56:33+01:00

TCS * What thermal lensing @ 120K? * back of the envelope calculation * * TCS design must: robust, flexible * Actuators * RHs: * Ok with room temperature TMs, what with cryogenics? * AdV design optimized to have the best uniformity:for ET segmented RH for higher order aberrations control (astigmatism)? * Recycling cavity projectors:

et_update_2017:telecon_6_oct

2017-10-06T12:28:58+01:00

* [Slides_no_xylo] * [120K coating update] ----