High angular resolution x-ray collimator

DETAILED DESCRIPTION In order to detect contraband such as explosive materials and illicit drugs, systems employing energy dispersive detectors and radiation collimators are needed.
U.
S.
Pat.
No.
5,007,072, issued to Ion Track Instruments on Apr.
9, 1991, discloses such an x-ray inspection system utilizing energy dispersive detectors and radiation collimators.
A polychromatic x-ray source is used to irradiate a piece of luggage.
The intensity of the diffracted rays are measured simultaneously at a fixed angle of about 2.
degree.
relative to the primary beam being emitted from the x-ray source.
In order for the energy dispersive detector to measure the intensity of the diffracted rays simultaneously at a fixed angle, a collimator must be employed to provide a sufficiently high resolution.
Typical radiation collimators have been used to perform gamma ray spectroscopy in areas such as nuclear medicine.
In this field, large gamma ray cameras are used to obtain images of patient's internal organs.
These collimators are constructed from lead and generally have a "honeycomb" appearance.
The x-rays pass through these open "honeycomb" areas at a solid angle and are measured by detectors.
The x-rays which impinge at angles outside the angular resolution of the collimator are absorbed in the lead walls.
The typical resolution of these collimators is only a few degrees of arc.
The effectiveness of the x-ray detector system disclosed in U.
S.
Pat.
No.
5,007,072 requires a substantially improved collimator with a resolution about 100 times greater than the conventional "honeycomb" collimator.
Thus, there is a need for a collimator with greater resolution.
In accordance with a preferred embodiment of the present invention, there is provided a collimator made from a bundle of optical fibers bonded together to form a solid core.
The solid core has an inner core and an outer core.
The inner core has a plurality of pores or channels extending through it that have been formed by removing the center of each optical fiber