dark matter search using high resolution emulsion m. natsume @nagoya university
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Dark Matter Search Using High Resolution Emulsion
M. Natsume @Nagoya University
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Detection of WIMP arrival direction (not annual modulation)
Sun
220 km/sec
Earth
WIMP wind is due to Sun’s motion through our Galaxy
Observe tracks of nuclear recoils from WIMP
WIMP wind
Detector : Nano Imaging Tracker
high resolution emulsion with 40nm sized AgBr crystal
Compare tracks parallel to the wind with tracks perpendicular to the wind.
keep detector oriented to WIMP wind by rotating mount like equatorial telescope
WIMP
Maxwellian distribution
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200 nm
NIT can detect nuclear recoil from WIMP
600 nm
Kr 1200km/sec (600keV)
expose NIT to 84Kr ion beam simulating 81Br recoil
Kr
NIT emulsion layer
15°
SEM
Kr 680km/sec (200keV)
TAC base
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enlarge recoil tracks for optical recognition
after development
200 nm
~ 1000 nm
uniform enlargement possible?
WIMP
enlarge !
200 nm
optical image
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Enlarge tracks of 5.3MeV alphas from Ra D-E source
before after
2.4 times enlargement
OPERA emulsion
160μm 160μm
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1 μm
optical microscope image after enlargement
electron microscope image