Speaker
Kensuke Homma
(Uni Hiroshima)
Description
The detection principle of charged particles developed so far is based on the
local inelastic processes such as ionizations and excitations with the energy
consumption above 1eV order. However, if one could utilize more
macroscopic processes such as polarizations in an electro-optical(EO) crystal
for the electric field sensing, the necessary energy consumption is expected
to be well below 1eV order. This opens up new applications for quasi-
nondestructive measurements especially for slow charged particles in
addition to the application for the beam diagnosis of relativistic charged
particles in accelerators. For the detection of polarizations caused by remote
electric fields of charged particles, laser lights transmitted by an EO crystal
with the local refractive index changes are diffracted and interfered by a lens
and the change of the diffraction pattern at the focal plane can be utilized to
sense the extremely small refractive index changes. In this talk, a result to
verify the detection principle will be presented. The first successful
measurement has been performed with LiNbO3 crystal with respect to a
weak DC electron beam of 1nA by using a Nd:YAG CW laser with the
intensity of 1W. The electron beam profile was 50μm(FWHM) and the kinetic
energy was 4keV which was located at the distance longer than 100μm
from the crystal surface. The change of the diffraction pattern at the focal
plane was observed associated with the existence of the remote electron
beam and the feature of the diffraction pattern was qualitatively confirmed.
Author
Kensuke Homma
(Uni Hiroshima)
