Boro-silicate polycapillary lens for collimation of x-rays

100 Pages·1.5 MB·English

by  Chase, Michael B

NPS ARCHIVE
1997.06
CHASE, M.
NAVAL POSTGRADUATE SCHOOL
MONTEREY, CALIFORNIA
THESIS
BORO-SILICATE POLYCAPILLARY LENS FOR
COLLIMATION OF X-RAYS
by
Michael B. Chase
June, 1997
Thesis Advisor: Xavier K. Maruyama
Approvedforpublic release; distribution isunlimited.
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1. AGENCY USEONLY(Leaveblank) 2. REPORTDATE 3. REPORTTYPEANDDATES COVERED
June, 1997 Master's Thesis
4. TITLEANDSUBTITLE 5. FUNDING NUMBERS
BORO-SJXICAT POLYCAPILLARY LENS FOR COLLMATION
OF X-RAYS
AUTHOR(S)
6.
Michael B. Chase
PERFORMINGORGANIZATIONNAME(S)ANDADDRESS(ES) PERFORMING
7.
Naval Postgraduate School ORGANIZATION
Monterey CA 93943-5000 REPORTNUMBER
SPONSORING/MONITORINGAGENCY NAME(S)ANDADDRESS(ES) 10. SPONSORING/MONITORING
AGENCYREPORTNUMBER
11. SUPPLEMENTARYNOTES The views expressed in this thesis are those oftheauthorand do notreflectthe
official policy orposition ofthe Department ofDefenseortheU.S. Government.
12a. DISTRIBUnON/AVAILABILITY STATEMENT 12b. DISTRIBUTIONCODE
Approved forpublic release; distribution is unlimited.
13. ABSTRACT(maximum200words)
The purpose of this thesis is to investigate the collimation of x-rays produced by transition
radiation using the NPS Electron Linear Accelerator. These measurements support the theory that x-
rays can be focused using a boro-silicate array of polycapillaries consisting of 258 bundles with 1387
micro-channels each. A 90 MeV electron beam incident upon a non-resonant mylar stack formed
transition radiation spatially distributed in an annular cone. The electron beam was deflected 30
degrees using a rare earth permanent magnet. The diverging x-rays incident upon the lens array were
A
transported through total external reflection and directed out of the array onto a phosphor screen.
digital camera recorded the phosphorescing image of the screen. Pixel intensity was analyzed to
determine x-ray intensity as a function oftwo dimensional spatial distribution.
Column average profiles of the pixel intensity show that the transition radiation intensity
retains its Gaussian distribution after being redirected from a diverging beam into a mostly parallel
beam. The intensity ofthe x-rays decreased by a factor of0.72 due to the obstructed area at the face of
the array and to imperfect admittance ofthe diverging x-ray cone into the polycapillary array.
14. SUBJECTTERMS 15. NUMBEROF
X-Rayfocusing,TransitionRadiation,LinearAccelerator, X-RayLithography,polycapillaries PAGES 90
16. PRICECODE
17. SECURITYCLASSIFICA- 18. SECURITYCLASSIFI- 19. SECURITYCLASSIFICA- 20. LIMITATIONOF
TIONOFREPORT CATIONOFTHIS PAGE TIONOFABSTRACT ABSTRACT
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Approvedforpublic release; distribution is unlimited.
BORO-SELICATE POLYCAPILLARY LENS FOR COLLIMATION OF X-RAYS
Michael B. Chase
LieutenantCommander, United States Navy
B.A., TheCollege ofWilliam andMary in Virginia, 1979
M.B.A., Jacksonville University, 1988
Submitted in partial fulfillmentofthe
requirements forthe degrees of
MASTER OF SCIENCEIN APPLIEDPHYSICS
from the
NAVAL POSTGRADUATESCHOOL
June, 1997
CWse,
Oft.
MONTEREY, CA93943-5101 10NTERE> >> 33943-5101
ABSTRACT
The purpose of this thesis is to investigate the collimation of x-rays produced by
transition radiation using the NPS Electron Linear Accelerator. These measurements support the
theory that x-rays can be focused using a boro-silicate array ofpolycapillaries consisting of258
bundles with 1387 micro-channels each. A 90 MeV electron beam incident upon a non-resonant
mylar stack formed transition radiation spatially distributed in an annular cone. The electron
beam was deflected 30 degrees using a rare earth permanent magnet. The diverging x-rays
incident upon the lens array were transported through total external reflection and directed out of
A
the array onto a phosphor screen. digital camera recorded the phosphorescing image of the
screen. Pixel intensity was analyzed to determine x-ray intensity as a function of two
dimensional spatial distribution.
Column average profiles ofthe pixel intensity show that the transition radiation intensity
retains its Gaussian distribution after being redirected from a diverging beam into a mostly
parallel beam. The intensity of the x-rays decreased by a factor of 0.72 due to the obstructed
area at the face of the array and to imperfect admittance of the diverging x-ray cone into the
polycapillary array.
VI
TABLE OF CONTENTS
INTRODUCTION
I. 1
THENEED FOR X-RAY FOCUSING
A.
1
B. THE USE OF TRANSITION RADIATION AS AN X-RAY SOURCE 2
POLYCAPEXARYLENS USE FOR X-RAY FOCUSING
C. 5
PARABOLIC MIRRORFOR X-RAY FOCUSING
D. 10
EXPERIMENTAL APPARATUS AND PROCEDURE
II. 13
TRANSITION RADIATION STACK
A. 13
THE POLYCAPELLARY LENS ARRAY
B. 14
LENS ARRAY COMPONENTS
C. 15
THE PHOSPHOR SCREEN
D. 19
X-RAY IMAGING
E. 19
F. PARABOLIC MIRROR FOR X-RAY FOCUSING 22
m. OBSERVATIONS AND DATA ANALYSIS 25
A. POLYCAPEXARY LENS DATA ANALYSIS 25
B. PARABOLIC MIRRORDATA ANALYSIS 29
IV CONCLUSIONS 37
APPENDIX A. THE THEORIES AND THE PHYSICS 39
A. CHRENKOV VERSUS TRANSITION RADIATION 39
B. TRANSITION RADIATION THEORY 42
C. SNELL'SLAW OF REFLECTION AND REFRACTION 45
D. POLYCAPEXARY WAVEGUIDE OPTICS 49
APPENDDC B. LITHOGRAPHY APPLICATIONS 53
A. POLYCAPILLARYLENS USE IN X-RAY LITHOGRAPHY 53
B. THE STEPS IN THE LITHOGRAPHIC PROCESS 54
C. X-RAY LITHOGRAPHY 55
APPENDrXC. THENPS LINEAR ACCELERATOR 57
A. INTRODUCTION TO THE LINAC 57
B. THEORY OF ELECTRONLINEAR ACCELERATION 58
C. ELECTRON EMISSION 59
D. ELECTRONMOTION IN A UNIFORM ELECTRIC FIELD 60
E. RELATTVISTIC ELECTRON MASS INCREASE 61
F. ACCELERATING STRUCTURE 64
G. THE RF POWER SYSTEM 66
H. ELECTRONBEAM INJECTION 67
THE RESONANT CAVITY 69
I.
THE KLYSTRON 72
J.
K. THE DEFECTION SYSTEM 74
L THEEND-STATION TARGET CHAMBER 75
vii
LIST OF REFERENCES
77
INITIAL DISTRIBUTION LIST
79
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