Hello all, Yesterday (friday 15/02/2013) David Monacchi and I visited LNGS, the Gran Sasso nuclear physics laboratory [1] and recorded some acoustic impulse responses of the spaces in which the Darkside50 experiment is currently being installed.
We will prepare a webpage with the results, pictures, etc., but in the meantime here are some first impressions. To be honest, very similar IRs could probably be obtained at many industrial sites using spaces of similar size and shape, but the ones we recorded are unique because the place is unique - and absolutely fascinating in all respects. LNGS is largest underground physics laboratory in the world, covered by 1400m meters of solid rock shielding it from most but not all cosmic radiation. It consists of three large halls each of them packed with experiments - there are normally 20 to 30 of those going on or being installed at any time. The most famous of those is probably OPERA, which last year seemed to have measured neutrinos travelling from CERN to Gran Sasso at a speed exceeding the speed of light - a result that later turned out to be due to an error in the extremely complex equipment used. OPERA is situated next to Darkside and has officially ended, but they are still processing the tens of thousands of photographic films packed in slabs of lead. All the mechanical handling this requires is done be dedicated robots which seem to be working round the clock. The scale of things at LNGS is really beyond imagination. There's one experiment that is monitoring 1600 channels of data with nanosecond resolution - that amounts to 1.6 Terasamples per second - for years and years. Not all data is stored of course (most is background noise) but still, that makes recording 64 channels of audio seem like child's play. There's another one that has been waiting for the next supernova explosion for almost 30 years (there are 2 or 3 of those per century). The Darkside experiment is meant to detect particle interactions that will (hopefully) confirm the existence of 'dark matter', the large proportion of matter that according to current theories of cosmology should exist but has evaded detection so far. Darkside50 consists of a cylindrical vessel, estimated size 9m diameter and some 12m high, which will be filled with water. At the center of this is a 'bathroom sized' sphere wich will be filled with argon at room temperature, and inside the sphere there will be a smaller container containing liquid argon (around -190 degrees C) [2]. All three of those spaces will have scintillation detectors (photomultipliers, able to detect a single photon), and judging by the big bundles of cables already installed there will be several hundreds of those. The two outer layers will act as an active shield for the core experiment using the liquid argon, not by blocking particles that would interfere with it, but by detecting them. The whole environment, including the outer shell, is a cleanroom so we had to wear the white plastic suits you know from crime investigation movies, including special shoes, nose and mouth mask, hair cover and gloves. This gets quite hot after some time. Also all equipment we used had to be cleaned before it could enter the space. All in all it was a rather unique experience. Many thanks to Richard Dobson who made this visit possible in the first place, and to all the people at LNGS who accomodated and helped us in every way they could. Ciao, [1] <http://www.lngs.infn.it> [2] <darkside.lngs.infn.it/ds-50> -- FA A world of exhaustive, reliable metadata would be an utopia. It's also a pipe-dream, founded on self-delusion, nerd hubris and hysterically inflated market opportunities. (Cory Doctorow) _______________________________________________ Sursound mailing list [email protected] https://mail.music.vt.edu/mailman/listinfo/sursound
