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Abstract Constraining Neutrinos As Background ABSTRACT CONSTRAINING NEUTRINOS AS BACKGROUND TO WIMP-NUCLEON DARK MATTER PARTICLE SEARCHES FOR DAMIC: CCD PHYSICS ANALYSIS AND ELECTRONICS DEVELOPMENT Melissa Jean Butner, MS Department of Physics Northern Illinois University, 2016 Steve Martin, Director Juan Estrada, Co-director The DaMIC (Dark Matter in CCDs) experiment searches for dark matter particles using charge coupled devices (CCDs) operated at a low detection threshold of 40 eV electron ⇠ equivalent energy (eVee). A multiplexor board is tested for DAMIC100+ which has the ability to control up to 16 CCDs at one time allowing for the selection of a single CCD for readout while leaving all others static and maintaining sub-electron noise. A dark matter limit is produced using the results of physics data taken with the DAMIC experiment. Next, the contribution from neutrino-nucleus coherent scattering is investigated using data from the Coherent Neutrino Nucleus Interaction Experiment (CON⌫IE) using the same CCD technology. The results are used to explore the performance of CCD detectors that ultimately will limit the ability to di↵erentiate incident solar and atmospheric neutrinos from dark matter particles. NORTHERN ILLINOIS UNIVERSITY DE KALB, ILLINOIS AUGUST 2016 CONSTRAINING NEUTRINOS AS BACKGROUND TO WIMP-NUCLEON DARK MATTER PARTICLE SEARCHES FOR DAMIC: CCD PHYSICS ANALYSIS AND ELECTRONICS DEVELOPMENT BY MELISSA JEAN BUTNER c 2016 Melissa Jean Butner A THESIS SUBMITTED TO THE GRADUATE SCHOOL IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE MASTER OF SCIENCE DEPARTMENT OF PHYSICS Thesis Director: Steve Martin Thesis Co-Director: Juan Estrada ACKNOWLEDGEMENTS This thesis has been possible because of the collective e↵orts of many people. I would first like to thank my advisor at Fermilab and committee chair, Dr. Juan Estrada, for helping me to complete the research described in this thesis. I especially appreciated the freedom to work independently I was given. This thesis has been possible because of his guidance, support and funding throughout my research. I would like to thank all members of the DAMIC and CO⌫NIE collaboration without whom this research would not be possible, especially Javier Ti↵enberg and Guillermo Fer- nandez Moroni. I would also like to thank Gustavo Cancelo for his support and guidance with teaching me about electrical schematics and hardware. IwouldliketothankKevinKukforinitiallyshowingmehowtooperatetheequipment and test CCDs in the lab at Sidet as well as being available to answer any question or help with problems that occasionally arose in the lab. I wish to thank everyone I have had the opportunity to work with during my time at Sidet: Tammy Hawke, Donna Kubik and Andrew Lathrop. I would also like to thank Marco Bonati for all of his enlightening conversations and assistance with Panview and CCDs. I would also like to thank my committee members Dr. Steve Martin and Dr. Yasuo Ito for taking time from their busy schedules to be on my thesis committee and to o↵er their insights regarding how to improve my thesis. I would like to thank Dr. Laurence Lurio, Dr. Yasuo Ito and the Department of Physics for continuing to fund me as a teaching assistant in the department so that I might pursue my interest in dark matter. iii I especially would like to thank Allyn Smith for being an excellent mentor as well as friend and for giving me the first of many opportunities to observe remotely using the NASA Infrared Telescope at Mauna Kea Observatory. Though it was cloudy, I completely enjoyed the experience and lead to my interest in astrophysics research. None of this work would have been possible without the continued support from my family and friends. My deepest thanks to Douglas Tucker and Sahar Allam for the occasional lunch or dinner as well as many enjoyable conversations at the wine and cheese. Iespeciallywouldliketosaythankyoutothebestparentsanyonecouldaskfor,David and Eileen, it is because of your selfless love and endless support that this is possible. My brother, Eric, deserves a special thanks for all Sunday nights of watching The Walking Dead together that proved invaluable for the reduction of stress. Lastly, I especially would like to thank the “love of my life”, Duncan Brown, who has been there the most through the good times as well as the stressful times, my sincere gratitude for your patience, support and advice. I am extremely thankful to him for staying up all night to talk while I was frustrated with day to day stresses and finally for helping me to stay focused as well as reminding me to take the occasional much needed break to maintain my sanity. DEDICATION This work is dedicated to my parents and Duncan, who have been a constant source of support and encouragement during the challenges of graduate school and life. Iamtrulythankfulforhavingyouinmylife. TABLE OF CONTENTS Page List of Tables . viii List of Figures. ix Chapter 1TheDarkMatterMystery. 1 1.1 Introduction . 1 1.2 Evidence for Dark Matter in Galaxies . 2 1.2.1 Galactic Rotation Curves . 3 1.2.2 Galaxy Clusters . 4 1.3 Cosmological Evidence for Dark Matter . 5 1.3.1 Cosmic Microwave Background . 5 1.3.2 Type Ia Supernovae . 7 2ParticleCandidatesforDarkMatter. 10 2.1 The Standard Model of Particle Physics . 10 2.2 Standard Model Neutrinos . 11 2.3 Basic Properties of Dark Matter . 11 2.4 Weakly Interacting Massive Particles . 13 2.4.1 Thermal Freeze Out . 13 2.4.2 Supersymmetry . 15 2.4.3 The Lightest Neutralino . 16 2.5 Axions . 17 vi Chapter Page 2.6 Other Candidates . 18 3 Dark Matter Detection via Nuclear Scattering Cross Section . 20 3.1 WIMP-Nucleus Scattering Cross Section . 20 3.2 Nuclear Form Factor . 21 3.3 Expected Recoil-Energy Spectra and Event Rates . 23 3.4 WIMP particle density and velocity distribution . 24 3.5 Annual Modulation . 25 3.6 Coherent Neutrino Scattering in Dark Matter Detectors . 26 3.6.1 Dark Matter Detection and the Neutrino Floor . 29 3.6.2 Neutrino Background in Dark Matter Detectors . 31 4ExperimentalDarkMatterSearches. 32 4.1 Direct Detection Searches . 32 4.1.1 Background for Dark Matter Experiments. 33 4.1.1.1 The Neutrino Floor . 33 4.1.2 Experimental Searches for Dark Matter . 34 4.1.3 Summary of Direct Detection Experimental Limits . 38 4.2 Other Experimental Dark Matter Searches . 38 4.2.1 Collider Searches . 38 4.2.2 Indirect Detection via WIMP Annihilation . 40 4.2.2.1 Gamma Rays . 41 4.2.2.2 Neutrinos . 42 4.2.2.3 Cosmic Ray Antimatter . 45 4.2.3 Axions . 46 vii Chapter Page 5 The DAMIC and CO⌫NIE Experiments . 49 5.1 Soudan Underground Laboratory . 49 5.2 DAMIC Experiment at SNOLAB . 50 5.2.1 Recent DAMIC Results . 51 5.2.2 DAMIC100 and 100+ . 52 5.3 CO⌫NIE Experiment. 54 6ChargeCoupledDevices. 57 6.1 CCD Pixel Operation . 58 6.2 CCDs as Particle Detectors . 62 6.3 CCD Characteristics: DAMIC & CO⌫NIE Experiments . 63 6.4 Energy Threshold and Calibration . 65 7 Analysis of DAMIC and CO⌫NIE Data . 67 7.1 DAMIC Analysis of the WIMP Exclusion Limit. 67 7.2 CO⌫NIE Analysis of the CCD Neutrino Contribution. 68 7.2.1 Physics Selection and Analysis . 68 8 Electronics for the next generation of the DAMIC/CO⌫NIE experiments. 74 8.1 Silicon Detector Testing Facility . 77 8.1.1 Single Cube Testing Setup. 77 8.1.2 Multi-CCD Testing Facility . 78 8.2 Prototype Multiplexor Test Results . 80 8.2.1 Results of Testing in the Single Cube . 84 8.2.2 First Results Testing in the MCCDTV . 84 9Conclusion. 87 References. 89 LIST OF TABLES Table Page 1.1 Energy density of the ⇤CDM. 5 1.2 Possible curvatures for the shape of the universe. 6 2.1 A summary of the fundamental SM particles and their proposed supersym- metric partners. Figure from [32].. 16 3.1 Properties for measuring CNS at a nuclear reactor. 28 8.1 Summary of CCD position on the focal plane and how it maps to the CCD selected using the MUX along with the associated output fits extension. 80 LIST OF FIGURES Figure Page 1.1 Galactic rotation curve for NGC 6503 (black squares). Shown are the con- tributions from the proposed dark matter halo, the luminous matter in the disk and gas. [3] . 3 1.2 The Bullet Cluster overlaid with the distribution of the total matter density (purple) inferred from gravitational lensing, and the distribution of baryonic matter (pink) inferred from X-ray observations by Chandra. [5]. 4 1.3 Power spectrum of temperature fluctuations in the Cosmic Microwave Back- ground detected by Planck at di↵erent angular scales on the sky. Figure from [15]. 6 1.4 68.3%, 95.4%, and 99.7% C.L. contours for the dark matter ⌦M and dark energy ⌦⇤ consensus model obtained from baryon acoustic oscillation (BAO), CMB, and SN measurements. The overlap region suggests an almost flat universe with ⌦ 0.317 and ⌦ 0.683. Figure from [16]. ..
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