Now in Japan, construction of a 25km-long linear
electron-positron collider JLC (Japan Linear Collider)
which reach TeV region at a center of mass energy has been proposed.
If the Higgs boson which is responsible for mechanism of mass
generation of whole the fundamental particles is discoverd,
we can are able to obtain a lot of knowledge for new physics
beyond the standard model.
The linear electron-positron collider is enable us to
identify final state of a reaction cleary for whole
collision energy used by elementary process, and is
suitable for precision measurements.
To accelarate energy with circular colliders, however, is
limited by energy loss due to synchrotron radiation
which increases as the force power of the beam energy.
Therefore linear collider is chooed for JLC.
JLC detecor is composed of a vertex detector, a central
drift chamber,calorimeters and muon detectors.
The Si-PAD detector which is made of finely segmented
silicon photodiodes is a part of the calorimeters.
Total effective area of the prototype Si-PAD detector
is 17.6 cm $B!_(B 17.6 cm with a number of 256 pads,
each of which has a size of 1.1 cm $B!_(B 1.1 cm.
The Si-PAD detector was tested using beam with momentum
from 1 GeV/c to 4 GeV/c at National Laboratry for
High Energy Physics(KEK).
As a result of comparison of experimental data with
Monte Carlo simulation, it is ascertained that Si-PAD
detector fill its funcion.