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UV imaging of extensive air showers at TeV energies. Item Type text; Dissertation-Reproduction (electronic) Authors Chantell, Mark Charles. Publisher The University of Arizona. Rights Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author. Download date 27/09/2021 22:28:30 Link to Item http://hdl.handle.net/10150/187295 INFORMATION TO USERS This manuscript ,has been reproduced from the microfilm master. UMI films the text directly from the original or copy submitted. Thus, some thesis and dissenation copies are in typewriter face, while others may be from any type of computer printer. The quality or this reproduction is dependent upon the quality or the copy submitted. 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Contact UMI directly to order. UMI A Bell & Howell Informallon Company 300 North Zeeb Road. Ann Arbor. MI4S106-1346 USA 313/761-4700 800:521-0600 UV IMAGING OF EXTENSIVE AIR SHOWERS AT TEV ENERGIES by Mark Charles Chantell A Dissertation Submitted to the Faculty of the DEPARTMENT OF PHYSICS In Partial Fulfillment ofthe Requirements For the Degree of DOCTOR OF PHILOSOPHY In the Graduate College THE UNIVERSITY OF ARIZONA 1995 UMI Number: 9604520 OMI Microform 9604520 Copyright 1995, by OMI Company. All rights reserved. This microform edition is protected against unauthorized copying under Title 17, United States Code. UMI 300 North Zeeb Road Ann Arbor, MI 48103 THE UNIVERSITY OF ARIZONA GRADUATE COLLEGE As members of the Final Examination Committee, we certify that we have read the dissertation prepared by Mark C Chantell --~~=-~~~~~--------------------- entitled UV Imaging of Extensive Air Showers at TeV Energies and recommend that it be accepted as fulfilling the dissertation of Philosophy/Physics Date g/I~ 195 Date ~ • Dater \ r;; (Ic{ /45 /9. t .1995" Date Final approval and acceptance of this dissertation is contingent upon the candidate's submission of the final copy of the dissertation to the Graduate College. I hereby certify that I have read this dissertation prepared under my direction and recommend that it be accepted as fulfilling the dissertation requirement. /9.6.199J Date 3 STATEMENT BY AUTHOR This dissertation has been submitted in partial fulfillment of requirements for an advanced degree at the University of Arizona and is deposited in the University Library to be made available to borrowers under rules of the Library. Brief quotations from this dissertation are allowable without special permission, provided that accurate acknowledgment of source is made. Requests for permission for extended quotation from or reproduction of this manuscript in whole or in part may be granted by the head of the major department or the Dean of the Graduate College when in his or her judgment the proposed use of the material is in the interests of scholarship. In all other instances, however, permission must be obtained from the author. 4 ACKNOWLEDGEMENTS This dissertation would not have been possible without the help of many people. In particular I would like to thank Dr. Trevor Weekes for his guidance and support during my dissertation work. To Kevin Harris I express my sincere thanks for his assistance in the understanding all the technical aspects of the experiment. I would also like to thank the rest of the Whipple collaboration, past and present, for their assistance and support of this work. In addition to the regular members of the Whipple collaboration I wish to express my thanks to Drs. Patrick Fleury, Eric Pare, Xavier Sarazin, Giuseppe Vacanti and especially Marcel Urban for many stimulating, and enlightening, discussions. To my Ph.D. committee members I express my appreciation for their input and direction. Dr. K.c. Hsieh deserves particular thanks for helping me to distill four years worth of research into a single, coherent, body of work. My wife and parents deserve my heartfelt appreciation for their support and encouragement. Finally I would like to thank the U.S. Department of Energy and the Smithsonian Astrophysical Observatory for their financial support of this work. 5 To my loving Wife whose never ending faith helped me to endure the most difficult times during my graduate studies. 6 TABLE OF CONTENTS LIST OF FIGURES ..................................................................................................... 8 LIST OF TABLES ...................................................................................................... 10 ABSTRACT ................................................................................................................ 11 I. INTRODUCTION ................................................................................................... 12 LI. GAMMA-RAY ASTRONOMy ................................................................ 12 1.2. AIR-CHERENKOV IMAGING ................................................................ 17 1.3. MOTIVATION FOR EXTENDING THE IMAGING TECHNIQUE INTO PERIODS OF BRIGHT MOON LIGHT ......................................... 19 1.4. ARTEMIS AND A UV VERSION OF THE WHIPPLE OBSERVATORY'S IMAGING CAMERA ............................................... 25 2. THE 10-METER TELESCOPE AND DATA ACQUISITION ELECTRONICS ..... 28 2.1. TELESCOPE MOUNT AND ELECTRONICS ........................................ 30 2.2. TELESCOPE TRACKING CAPABILITIES ............................................ 32 2.3. THE UV CAMERA .................................................................................. 32 2.3.1. THE SOLAR-BLIND PHOTOMULTIPLIER TUBES ............... 36 2.3.2. UVFILTER ............................................................................... 38 2.3.3. SCINTILLATOR DETECTOR .................................................. 39 2.4. DATA ACQUISITION ELECTRONICS .................................................. 41 2.5. CONVERSION FROM VISIBLE TO UV OPERATION .......................... 45 3. IMAGING EXTENDED AIR SHOWERS .............................................................. 47 3.1. THE WHIPPLE IMAGING TECHNIQUE ............................................... 47 3.1.1. GAMMA-RAY INITIATED AIR SHOWERS ........................... 48 3.1.2. HADRON INITIATED AIR SHOWERS .................................. .49 3.1.3. CHERENKOV RADIATION IN AIR SHOWERS ..................... 50 3.1.4. IMAGING AIR SHOWERS ....................................................... 53 3.2. ATTENUATION OF UV LIGHT BY THE EARTH'S ATMOSPHERE ........................................................................................ 59 3.2. L RAYLEIGH AND MIE SCATTERING ..................................... 60 3.2.2. ABSORPTION BY MOLECULAR OXYGEN AND OZONE ...................................................................................... 63 3.3. EXPECTED RATE OF GAMMA-RAY EVENT TRIGGERS .................. 69 4. UV CAMERA RESPONSE TO THE NIGHT SKy ................................................ 73 4.1. RESPONSE OF THE PHOTOMULTIPLIER TUBES TO THE NIGHT SKy ............................................................................................. 74 4.1.1. DEFINITION OF SKY NOISE IN THE SOLAR-BLIND PHOTOMULTIPLIER TUBES .................................................. 77 4.1.2. PHOTOELECTRON TO DIGITAL COUNT CONVERSION FACTOR .......................................................... 80 4.1.3. SENSITIVITY OF THE UV PHOTOMULTIPLIER TUBES TO STAR LIGHT ......................................................... 85 7 TABLE OF CONTENTS - Continued 4.1.4. CORRELATION BETWEEN PMT NOISE AND THE PRESENCE OF THE MOON .................................................... 87 4.2. CAMERA TRIGGER RESPONSE ........................................................... 91 5. IMAGING CHARACTERISTICS OF THE UV CAMERA ..................................... 98 5.1. DATA PROCESSING .............................................................................. 98 5.1.1. PMT CALIBRATION ................................................................ 100 5.1.1.1. HARDWARE PEDESTAL SUBTRACTION .............. 100 5.1.1.2. GAIN MATCHING ..................................................... 101 5.1.2. IMAGE CLEANING .................................................................. 106 5.1.3. IMAGE PARAMETERIZATION ............................................... 107 5.2. GAMMA-RAY CHARACTERIZATION ................................................. 114 5.2.1. BACKGROUND IMAGES IN THE UV .................................... 114 5.2.2. GAMMA-RAY