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. JAVAi ^OST'^0lJATESCH0O 10NTERF 3943-5101 fJ^EYKNOX LIBRARY REPORT DOCUMENTATION PAGE FormApprovedOMBNo.0704-01S Publicreportingburdenforthiscollectionofinformationisestimatedtoaverage1 hourperresponse,includingthetimeforreviewinginstruction,searchingexistingdatasources, gatheringandmaintainingthedataneeded,andcompletingandreviewingthecollectionofinformation.Sendcommentsregardingthisburdenestimateoranyotheraspectofthis collectionofinformation,includingsuggestionsforreducingthisburden,toWashingtonHeadquartersServices,DirectorateforInformationOperationsandReports,1215 JeffersonDavisHighway,Suite1204,Arlington,VA22202-4302,andtotheOfficeofManagementandBudget,PaperworkReductionProject(0704-0188)WashingtonDC 20503. 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 UL Unclassified Unclassified Unclassified NSN7540-01-280-5500 StandardForm298 (Rev. 2-89) PrescribedbyANSISid.239-18298-102 11 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 Vlll