Higher order parametric x-rays

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by  Osborne, Michael James.;Maruyama, Xavier K.

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NAVAL POSTGRADUATE SCHOOL
Monterey
California
,
THESIS
Higher Order Parametric X-Rays
by
Michael James Osborne
December 1991
Thesis Advisor: Xavier *;. Maruyama
Approved for public release; distribution is unlimited.

Approved for public release; distribution is unlimited
Higher Order Parametric X-Rays
by
Michael J. Osborne
Lieutenant, United States Navy
B.S. The Citadel
,
Submitted in partial fulfillment
of the requirements for the degree of
MASTER OF SCIENCE IN PHYSICS
from the
NAVAL POSTGRADUATE SCHOOL
December 1991
j
Karlheinz E. Woehler, Chairman
Department of Physics
11
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Higher Order Parametric X-Rays
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Osborne, Michael J.
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Master's Thesis December 1991 103
I6 SUPPLEMENTARY NOTATION
The views expressed in this thesis are those of the author and do not reflect the
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official policy or position of the Department of Defense or the U.S. Government.
I7 COSATI CODES 18 SUBJECT TERMS (Continue on reverse if necessary and identify by block number)
FIELD GROUP SUB-GROUP Parametric X-rays, PXR, Higher Order PXR, Easy-Mover
19 ABSTRACT (Continue on reverse if necessary and identify by block number)
Parametric x-radiation (PXR) may be described as the Bragg scattering of virtual photons to produce real x-rays
which satisfy the Bragg condition dsin =n;u where « is the angle between the electron beam direction and a
crystal axis. Enhanced higher order pafrtametric x-radiation from the (002) plane of a mosaic graphite crystal
has been observed. Production of PXR of the order n=2 exceed that from the first order, and x-rays of order
up to n=6 are readily seen. The production of higher order x-radiation is obtained by using a thick crystal
where the formation and attenuation lengths are exploited to enhance higher energy x-ray formation relative to
the lower energy first order x-radiation. Photons of energy 5 to 30 KeV have been measured. The experiment
was conducted with a 90 MeV electron beam from the Naval Postgraduate School electron linear accelerator. A
three axis target position program, Easy-Mover, was developed to allow for precision orientation of the crystal
axis with respect to the electron beam.
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Abstract
Parametric x-radiation (PXR) may be described as the Bragg
scattering of virtual photons to produce real x-rays which satisfy
the Bragg condition dsing=nl where is the angle between the
g
/
electron beam direction and a crystal axis. Enhanced higher order
parametric x-radiation from the {002} plane of a mosaic graphite
crystal has been observed. Production of PXR of the order n=2
exceed that from the first order, and x-rays of order up to n=6 are
readily seen. The production of higher order x-radiation is
obtained by using a thick crystal where the formation and
attenuation lengths are exploited to enhance higher energy x-ray
formation relative to the lower energy first order x-radiation.
Photons of energy 5 to 30 KeV have been measured. The experiment
was conducted with a 90 MeV electron beam from the Naval
Postgraduate School electron linear accelerator. A three axis
target position program, Easy-Mover, was developed to allow for
precision orientation of the crystal axis with respect to the
electron beam.
in
. . . ......
P /
TABLE OF CONTENTS
I INTRODUCTION 1
II THEORETICAL BACKGROUND 2
III EXPERIMENTAL PROCEDURE 8
A. PXR EXPERIMENT 8
B PEAK INTENSITY RATIOS 37
C. ROCKING DATA 49
D. PXR EXPERIMENTAL SETUP 58
E LINAC TUNEUP PROCEDURE 59
F. PULSE HEIGHT ANALYSIS PROCEDURE 60
V. CONCLUSION AND RECOMMENDATIONS 62
APPENDIX: EASY-MOVER PROGRAM 64
A. INITIAL SUBROUTINE 64
B MAIN SCREEN 65
C ROTATION SUBSCREEN 65
D TILT SUBSCREEN 67
E HEIGHT SUBSCREEN 68
F. INTERACTIVE PROGRAM 69
G. EASY-MOVER COMPUTER PROGRAM 70
LIST OF REFERENCES 96
INITIAL DISTRIBUTION LIST 98
IV