Askaryan effect in salt: SLAC T460, June 2002. 4lb high-purity synthetic rock-salt bricks (density=2.07) – 6 tons of it. + some filler from local grocery store… Makes & contains the shower. T460 rock-salt target. Embedding 21 dual antennas (and lots of cable)
4lb high-purity synthetic rock-salt bricks (density=2.07) – 6 tons of it.
+ some filler from local grocery store…
Makes & contains the shower
Bremsstrahlung beam from 28.5 GeV e-
Beam exit point shown above
good indicator of transverse size of shower! -- at 15 radiation lengths.
Shows rise with frequency expected for Cherenkov
Loss of coherence roll-off at ~5-10GHz also likely
Side antennae: horns & log-periodic
Verify Askaryan process: silica sand, SLAC T444, 2000
Identify radio-transparent natural salt structures 2001
Ground Penetrating Radar tests from 1970’s give strong indications
Hockley salt dome tests (Gorham et al. 2002) confirm La>250m
Extend accelerator results to rock salt 2002
SLAC T460: salt behaves as predicted!
Cosmic-ray testbed for antenna development/signal characterization 2002
In progress since 2003
Site studies and selection2005-2006
Detector construction & deployment 2007-2010