The objective of this proposal is to demonstrate biologically significant images with a new type of microscope of a novel and very simple design. In general, this microscope uses soft x-rays as the imaging radiation. The geometry of the microscope is very similar to the field emission microscope. Instead of using a solid emitter, the instrument uses a special cone-like, hollow emitter. The specimen to be examined is placed inside the hemispherical emitter tip. Soft x-rays are beamed through the specimen and onto the tip membrane. The tip membrane is transparent to x-rays and is coated with a high efficiency photoemitter. Photoelectrons are liberated Into the vacuum, outside the emitter tip, in a pattern corresponding to the x-ray absorption of the specimen (contact image). The photoelectrons are accelerated radially to a detector by a high voltage on the emitter. A magnified, high resolution (100 _10001), real time image results. This instrument has the potential for valuable use in biomedicine. Specimens can remain wet, unstained, and unsectioned. This technology has already been demonstrated with harder x-rays. Phase I research will address the more demanding technology needed for utilizing the desired ultrasoft x-rays and biological specimens.
