  We have evaluated the performance of a fine pitch CdTe Double-sided Strip
Detector (CdTe-DSD), which was originally developed for the focal plane
detector of a hard X-ray telescope to observe the Sun. The detector has a
thickness of 750 um and has 128 strip electrodes with a 60 um strip pitch
orthogonally placed on both sides of the detector and covers an energy range 4
keV to 80 keV. The study of the depth of photon interaction and charge sharing
effects are of importance in order to provide good spectroscopic and imaging
performance. We study the tail structure observed in the spectra caused by
charge trapping and develop a new method to reconstruct the spectra based on
induced charge information from both anode and cathode strips. By applying this
method, energy resolutions (FWHM) of 0.76 keV and 1.0 keV can be obtained at
photon energies of 14 keV and 60 keV, respectively, if the energy difference
between the anode and cathode is within 1 keV. Furthermore, the tail component
at 60 keV is reduced, and the energy resolution of the 60 keV peak is improved
from 2.4 keV to 1.5 keV (FWHM) if the energy difference is greater than 1 keV.
In order to study the imaging performance, we constructed a simple imaging
system using a 5 mm thick tungsten plate that has a pinhole with a diameter of
100 um. We utilize a Ba-133 radioisotope of 1 mm in diameter as a target source
in combination with a 100 um slit made from 0.5 mm thickness tungsten. We
imaged the Ba-133 source behind the 100 um slit using a 30 keV peak, with a 100
um pinhole placed at the center of the source-detector distance. By applying a
charge sharing correction between strips, we have succeeded in obtaining a
position resolution better than the strip pitch of 60 um.
