Focusing of x-rays using micromachined silicon lobster eye lenses
We are developing a novel x-ray lens, based on a one-dimensional analogue of the optical system of the lobester's eye, that is capable of making spatially resolved observations of celestial x-ray sources up to 10 keV with an angular resolution of 30[double prime] and an essentially unlimited field of view. Most standard x-ray telescopes use large reflecting surfaces curved in a unique shape to ofcus x-rays by total external reflection. The lobester eye lens consists of a large number of small, closely-packed reflecting surfaces that are flat and parallel. Lobester eye designs to date have consisted of large arrays of macroscopically aligned reflecting planes. These lenses have had the disadvantage of large pore width, leading to poor angular resolution, and large size and weight. The need for smaller, more closely spaced, flat, parallel surfaces lends itself to silicon micromachining. We have fabricated and tested silicon lenses suitable for focusing soft x-rays. We used a concentrated KOH solution to anisotropically etch (110) oriented single crystal silicon wafers; the resulting surfaces were aligned with the (111) planes perpendicular to the face. The pores were 50 [mu]m wide and 800 [mu]m deep, for an aspect ratio fo 40:1. We report on the fabrication techniques, measurements of the surface microroughness of the reflecting planes, and x-ray beam tests of the lenses. Future development will focus on coating the reflecting surfaces with metal to increase the reflection efficiency and on curing the lenses to image objects at astronomical distances. X-ray lenses may also be applied to other types of research.
- OSTI ID:
- 6669969
- Report Number(s):
- CONF-930189-; CODEN: AASBAR
- Journal Information:
- American Astronomical Society, Bulletin; (United States), Vol. 24:4; Conference: 181. meeting of the American Astronomical Society (AAS), Phoenix, AZ (United States), 3-7 Jan 1993; ISSN 0002-7537
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
LENSES
FABRICATION
MEASURING INSTRUMENTS
TESTING
SOFT X RADIATION
FOCUSING
ASPECT RATIO
COSMIC X-RAY SOURCES
RESOLUTION
SILICON
COSMIC RAY SOURCES
ELECTROMAGNETIC RADIATION
ELEMENTS
IONIZING RADIATIONS
RADIATIONS
SEMIMETALS
X RADIATION
440100* - Radiation Instrumentation