The Estimated Limits For A 5g LE-Ge Detector Q. Yue Tsinghua Univ. 2003.9.22
matter 0.3 baryon 0.01-0.03 lum 0.003 Components of the Universe: matter 0.3 baryon 0.01-0.03 lum 0.003 It shows: DM is the dominant component of the universe. Main part of it is Non-baryonic DM.
...... Massive neutrinos WIMP (Weekly Interactive Massive Particles ) Neutralino (Lightest super-symmetric particle) Axion ......
Direct Detection of WIMPs
The basic conditions of WIMP detector : High detection efficiency High pure target material Good shielding Good PSD capability Low threshold
Principles of direct detection: ER : the recoil energy E0 : the most probable incident energy of a dark matter particle of mass MD r : a kinematical factor R : the event rate ( 1/KeV · Day · Kg ) R0 : the total event rate ( 1/Day · Kg )
The possible mass range of WIMPs: 1 — 1000 GeV c-2 Typical recoil energies are in the range 0-100 keV. So good shielding is necessary to eliminate nuclear recoils from neutrons produced by cosmic ray muons. Methods of discriminating between nuclear recoils and electrons
The right-hand side is considerably complicated owing to the following corrections. a Detector on the Earth, in orbit around sun, and solar system moving through the Galaxy. b The Quenching Factor. c The target may consist of more than one elements. d Instrumental resolution and threshold effects. e SD & SI f Form factor
Take account all of these factors: vmax = vescape = 650km/s
DAMA results:
Our estimated results: Target mass: 5g QF: 0.25 Counts rate: 0.1 /keV·kg·day Threshold: 100KeV