Speaker
Dr
Junko Hiraga
(JAXA/ISIS, Kanagawa, Japan)
Description
Charge-coupled devices (CCDs) are widely used in soft X-ray
Astronomy as a focal plane detector which has a capability both of
good spatial resolution and good energy resolution up to 10 keV,
simultaneously. For the future X-ray space mission, the thick CCDs
are developed to improve the quantum e±ciency of high energy X-rays
beyond 10 keV.
A mesh experiment has been, so far, the only practical technique to
study CCD response with subpixel resolution. The mesh technique has
revealed the X-ray response within a pixel for various types of CCDs
(see e.g., Hiraga et al. 2001[1]). Hiraga et al. [2] developed this
technique to directly measure the final charge cloud shape. However
the mesh experiment is valid for X-rays only when they can pass
through the mesh at a hole. The mesh of the out-of-hole position
must be opaque for X-rays. Employing the gold mesh of about
13 µm thickness that is the thickest one in current production, the
e®ective energy range was thought to have an upper limit of 7 keV.
This fact has prevented us to measure the charge cloud shape for
higher energy X-rays.
We have proposed the new method to produce the novel multi-
collimator using Barium Phosphate (BP-1) glass which has originally
developed as a solid state track detectors (Wang et al. 1988[3]).
The BP-1 collimator enables us to determine the interaction position
of each X-ray photon much precisely than the CCD pixel size ( 10µm
in general) up to 20 keV Xrays.
We performed the first experiment of this project in which 80-
100MeV/nucleon of Xe beam was irradiated to the 1.3mm-thick-BP-1
glass. After the etching process, we obtained the first prototype of
BP-1 collimator. It has lots of tapered pinholes which are randomly
distributed, » 104 holes cm−2 with high aspect ratio. In this
conference, we will report the novel collimator and the results of
an application to the X-ray CCDs.
Primary author
Dr
Junko Hiraga
(JAXA/ISIS, Kanagawa, Japan)
