The Pennsylvania State University The Graduate School CHARACTERIZATION AND APPLICATIONS OF HYBRID CMOS DETECTORS IN X-RAY ASTRONOMY A Dissertation in Astronomy and Astrophysics by Stephen Bongiorno (cid:13)c 2013 Stephen Bongiorno Submitted in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy August 2013 The dissertation of Stephen Bongiorno was reviewed and approved∗ by the follow- ing: Abraham Falcone Senior Research Associate and Associate Professor of Astronomy Dissertation Advisor, Chair of Committee David Burrows Professor of Astronomy Larry Ramsey Professor of Astronomy Mike Eracleous Professor of Astronomy Stephane Coutu Professor of Physics Donald Schneider Professor of Astronomy Department Head ∗Signatures are on file in the Graduate School. Abstract The hybrid CMOS detector (HCD) is a powerful focal plane array (FPA) archi- tecture that has begun to benefit the visible-infrared astronomical community and is poised to do the same for X-ray astronomy. Since Servicing Mission 4 in 2009, an HCD has given the Hubble Space Telescope’s Wide-field Camera 3 improved imaging capability in the near-infrared. HCDs have been specified to operate at the focal plane of every science instrument on board the James Webb Space Tele- scope. A major goal of the Penn State X-ray Detector Group has been to modify the flexible HCD architecture to create high performance X-ray detectors that will achieve the currently unmet FPA requirements set by next-generation telescopes. These devices already exceed the radiation hardness, micrometeoroid tolerance, and high speed noise characteristics of current-generation X-ray charge coupled devices (CCDs), and they are on track to make a breakthrough in high count rate performance. This dissertation will begin with a presentation of background material on the detection of X-rays with semiconductor devices. The physics relevant to photon detection will be discussed and a review of the detector development history that led to the current state of the art will be presented. Next, details of the HCDs that our group has developed will be presented, followed by noise, energy resolution, and interpixel capacitance measurements of these detectors. A large part of my work over the past several years has consisted of designing, building, and carrying out tests with a laboratory apparatus that measures the quantum efficiency of HCDs. Details of this design process as well as the successful measurements that resulted will be presented. The topic of discussion will then broaden to the HCD’s current and future roles in X-ray astronomy. The dissertation will close with the presentation of a successful project that used Swift XRT data to confirm the binary nature of the TeV emitting object HESS J0632+057, making it one of five confirmed TeV high mass X-ray binaries. iii Table of Contents List of Figures viii List of Tables xii Acknowledgments xiii Chapter 1 The Detection of X-rays with Silicon Devices 1 1.1 The Interaction of Radiation With Silicon . . . . . . . . . . . . . . 3 1.1.1 Photon Absorption and Charge Generation . . . . . . . . . . 4 1.1.1.1 Photon-matter Interaction Mechanisms . . . . . . . 5 1.1.1.2 Consequences of the Solid State . . . . . . . . . . . 6 1.1.2 Charge Collection . . . . . . . . . . . . . . . . . . . . . . . . 7 1.1.3 Charge Transfer and Readout . . . . . . . . . . . . . . . . . 11 1.2 CCDs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 1.2.1 Basic Operation . . . . . . . . . . . . . . . . . . . . . . . . . 13 1.2.2 Advantages . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 1.2.3 Disadvantages . . . . . . . . . . . . . . . . . . . . . . . . . . 15 1.2.3.1 Destructive Readout . . . . . . . . . . . . . . . . . 15 1.2.3.2 Power Consumption . . . . . . . . . . . . . . . . . 16 1.2.3.3 Radiation Hardness . . . . . . . . . . . . . . . . . . 16 1.2.3.4 Pile-up . . . . . . . . . . . . . . . . . . . . . . . . 18 1.3 CMOS: A New Competitor in the X-ray . . . . . . . . . . . . . . . 19 1.3.1 Monolithic CMOS . . . . . . . . . . . . . . . . . . . . . . . 22 1.3.1.1 CTE and Radiation Hardness . . . . . . . . . . . . 22 1.3.2 Sensitivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 1.3.3 Hybrid CMOS Devices . . . . . . . . . . . . . . . . . . . . . 23 iv 1.3.3.1 The PIN diode . . . . . . . . . . . . . . . . . . . . 26 1.3.3.2 HCDs: The Good and the Bad . . . . . . . . . . . 27 Chapter 2 PSU Detector Hardware 30 2.1 TIS HAWAII Arrays . . . . . . . . . . . . . . . . . . . . . . . . . . 30 2.1.1 Reference Pixels . . . . . . . . . . . . . . . . . . . . . . . . . 33 2.1.2 Bare MUX . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 2.1.3 Anti-Reflection Coating . . . . . . . . . . . . . . . . . . . . 35 2.1.4 Filter Deposition . . . . . . . . . . . . . . . . . . . . . . . . 35 2.2 TIS SIDECARTM . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 Chapter 3 Data Reduction and Measurements of HCD Characteristics 41 3.1 Test Stand . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 3.1.1 Temperature Control . . . . . . . . . . . . . . . . . . . . . . 41 3.1.2 Vacuum Chamber . . . . . . . . . . . . . . . . . . . . . . . . 42 3.1.3 X-ray Sources . . . . . . . . . . . . . . . . . . . . . . . . . . 42 3.2 Data Acquisition . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 3.2.1 Readout Schemes . . . . . . . . . . . . . . . . . . . . . . . . 43 3.2.2 FET Leakage Current . . . . . . . . . . . . . . . . . . . . . 44 3.2.3 Row Noise Correction . . . . . . . . . . . . . . . . . . . . . 45 3.2.4 Substrate Bias Optimization . . . . . . . . . . . . . . . . . . 47 3.3 Grading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 3.4 System Gain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 3.4.0.1 Preamplifier Gain Optimization . . . . . . . . . . . 52 3.4.0.2 Gain Measurement . . . . . . . . . . . . . . . . . . 53 3.5 Interpixel Capacitance . . . . . . . . . . . . . . . . . . . . . . . . . 54 3.5.1 Deconvolution . . . . . . . . . . . . . . . . . . . . . . . . . . 61 3.5.2 IPC Discussion . . . . . . . . . . . . . . . . . . . . . . . . . 62 3.6 Read Noise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64 3.7 Energy Resolution . . . . . . . . . . . . . . . . . . . . . . . . . . . 65 3.8 Permanent Threshold Shift . . . . . . . . . . . . . . . . . . . . . . . 69 Chapter 4 Measurements of HCD quantum efficiency 73 4.1 Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73 4.2 Various Methodologies . . . . . . . . . . . . . . . . . . . . . . . . . 78 4.2.1 NIR and Optical QE . . . . . . . . . . . . . . . . . . . . . . 79 4.2.2 UV and X-ray QE . . . . . . . . . . . . . . . . . . . . . . . 80 v 4.3 Experimental Design . . . . . . . . . . . . . . . . . . . . . . . . . . 84 4.3.1 Vacuum System . . . . . . . . . . . . . . . . . . . . . . . . . 85 4.3.2 Cryogenics and Temperature Control . . . . . . . . . . . . . 93 4.3.3 Laboratory X-ray Sources . . . . . . . . . . . . . . . . . . . 101 4.3.4 Gas Flow Proportional Counter . . . . . . . . . . . . . . . . 115 4.3.5 Detector Alignment . . . . . . . . . . . . . . . . . . . . . . . 135 4.4 Experimental Result . . . . . . . . . . . . . . . . . . . . . . . . . . 137 4.4.1 Window Calibration Result . . . . . . . . . . . . . . . . . . 137 4.4.2 QE Data Acquisition . . . . . . . . . . . . . . . . . . . . . . 138 4.4.3 H1RG QE Data Reduction . . . . . . . . . . . . . . . . . . . 142 4.4.4 Proportional Counter Data Reduction . . . . . . . . . . . . 145 4.4.5 QE Result . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147 4.4.6 QE Error Analysis . . . . . . . . . . . . . . . . . . . . . . . 150 4.5 Modeling HCD Quantum Efficiency . . . . . . . . . . . . . . . . . . 153 4.6 Future QE Measurements . . . . . . . . . . . . . . . . . . . . . . . 155 Chapter 5 The future use of HCDs in X-ray astronomy 156 5.1 Small Missions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156 5.2 Large Missions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157 Chapter 6 The X-ray Confirmation of HESS J0632+057 as a γ-ray Binary 158 6.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158 6.2 The Observations . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160 6.3 Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161 6.4 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162 6.4.1 Peak Fitting . . . . . . . . . . . . . . . . . . . . . . . . . . . 163 6.4.2 Lomb-Scargle . . . . . . . . . . . . . . . . . . . . . . . . . . 164 6.4.3 Autocorrelation . . . . . . . . . . . . . . . . . . . . . . . . . 165 6.4.4 Significance of the Period . . . . . . . . . . . . . . . . . . . 166 6.5 Discussion & Conclusions . . . . . . . . . . . . . . . . . . . . . . . 168 Appendix A Mechanical Drawings 172 A.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172 Appendix B Electronics Schematics 189 B.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189 vi B.2 QE Test Stand . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189 B.2.1 Heater Power Supply . . . . . . . . . . . . . . . . . . . . . . 189 B.2.2 RTD Current Source . . . . . . . . . . . . . . . . . . . . . . 195 Appendix C Code 201 C.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201 C.2 Data Reduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201 C.3 QE Teststand . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 234 C.4 Thesis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 274 Bibliography 276 vii List of Figures 1.1 Energy level splitting . . . . . . . . . . . . . . . . . . . . . . . . . . 7 1.2 Energy levels of a solid . . . . . . . . . . . . . . . . . . . . . . . . . 8 1.3 Semiconductors used in photon detectors . . . . . . . . . . . . . . . 9 1.4 CCD operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 1.5 Passive and active pixel sensors . . . . . . . . . . . . . . . . . . . . 21 1.6 APS apmlifiers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 1.7 HyViSITM cutaway schematic . . . . . . . . . . . . . . . . . . . . . 24 1.8 PN junction band structure . . . . . . . . . . . . . . . . . . . . . . 27 2.1 H1RG-125 picture . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 2.2 Simplified HxRG electronics schematic . . . . . . . . . . . . . . . . 35 2.3 Suzaku OBF transmission . . . . . . . . . . . . . . . . . . . . . . . 37 2.4 Chandra OBF transmission . . . . . . . . . . . . . . . . . . . . . . . 38 2.5 JWST SIDECARTM . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 3.1 Cube chamber picture . . . . . . . . . . . . . . . . . . . . . . . . . 43 3.2 SIDECARTM signal chain . . . . . . . . . . . . . . . . . . . . . . . . 46 3.3 Row noise subtraction . . . . . . . . . . . . . . . . . . . . . . . . . 47 3.4 Simulation of charge cloud spreading as a function of bias voltage . 48 3.5 Measurement of charge cloud spreading as a function of bias voltage 49 3.6 Percent split histogram . . . . . . . . . . . . . . . . . . . . . . . . . 51 3.7 Low secondary threshold spectrum . . . . . . . . . . . . . . . . . . 54 3.8 Event pixel number distribution . . . . . . . . . . . . . . . . . . . . 55 3.9 Line emission peak position as a function of energy . . . . . . . . . 56 3.10 Schematic of the 5 pixel IPC model . . . . . . . . . . . . . . . . . . 57 3.11 CopperLandManganeseKX-rayimagesshowingchargespreading and IPC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 3.12 IPC deconvolution . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 3.13 Aluminum, chlorine, and manganese combined spectrum . . . . . . 67 3.14 Energy resolution as a function of energy . . . . . . . . . . . . . . . 68 3.15 Optimized secondary event thresholds as a function of energy . . . . 69 viii 3.16 Manganese spectrum optimized for energy resolution . . . . . . . . 70 3.17 Permanent threshold shift . . . . . . . . . . . . . . . . . . . . . . . 71 4.1 Example optical QE(E) for an H2RG . . . . . . . . . . . . . . . . . 75 4.2 Density of states in silicon . . . . . . . . . . . . . . . . . . . . . . . 76 4.3 Reflectance and absorption coefficient for silicon as a function of energy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78 4.4 Silicon photodiodes from IRD . . . . . . . . . . . . . . . . . . . . . 81 4.5 Synchrotron X-ray light source facility layout . . . . . . . . . . . . . 83 4.6 QE measurement apparatus used by Kenter et al. . . . . . . . . . . 84 4.7 Drawing of the QE test-stand in the PSU vacuum chamber . . . . . 85 4.8 X-ray transmission through air, vacuum, and helium . . . . . . . . 87 4.9 Sublimation curve on the phase diagram of water . . . . . . . . . . 88 4.10 Routing layout of the QE test-stand . . . . . . . . . . . . . . . . . . 94 4.11 Mechanical drawing of the QE test-stand . . . . . . . . . . . . . . . 98 4.12 Picture of the disassembled cryostat cold strap . . . . . . . . . . . . 102 4.13 Temperature data of the test-stand dewar and H1RG during QE data acquisition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103 4.14 Electronic transitions that produce X-ray emission . . . . . . . . . . 104 4.15 X-ray generation, active layer self-attenuation, and sealant layer attenuation in the VZ-2937 55Fe source . . . . . . . . . . . . . . . . 108 4.16 55Mn Kβ/Kα line ratio plotted as a function of angle with respect to the source normal . . . . . . . . . . . . . . . . . . . . . . . . . . 109 4.17 Exploded diagram of the 55Fe source holder . . . . . . . . . . . . . 110 4.18 Schematic of a simple α particle fluorescent X-ray source . . . . . . 111 4.19 Technical drawing of a Henke tube X-ray source . . . . . . . . . . . 112 4.20 Diagram of a typical Manson X-ray tube . . . . . . . . . . . . . . . 113 4.21 Cross-section view of a coil of filament wire . . . . . . . . . . . . . . 115 4.22 Cross-section schematic detailing the gas flow proportional counter theory of operation . . . . . . . . . . . . . . . . . . . . . . . . . . . 117 4.23 Typical gas gain and count rate behavior as a function of propor- tional counter anode voltage . . . . . . . . . . . . . . . . . . . . . . 120 4.24 Oscilloscope measurements of proportional counter output . . . . . 124 4.25 Results of the proportional counter dead time experiment . . . . . . 125 4.26 Mechanical failure of a proportional counter window . . . . . . . . . 130 4.27 Comparison of PSU X-ray transmission and cross section code out- put to NIST and LBNL code outputs . . . . . . . . . . . . . . . . . 133 4.28 Vector diagram of the detector alignment parameters . . . . . . . . 137 4.29 Pixel value distribution of the center (brightest) pixel of events detected with a primary threshold of 40 DN . . . . . . . . . . . . . 143 ix 4.30 Energy spectrum of the total charge in events, summed using a 39 DN secondary threshold . . . . . . . . . . . . . . . . . . . . . . . . 144 4.31 Combined H1RG data set . . . . . . . . . . . . . . . . . . . . . . . 145 4.32 Background subtracted proportional counter spectra acquired dur- ing QE data acquisition . . . . . . . . . . . . . . . . . . . . . . . . 147 4.33 QE error analysis Monte-Carlo result . . . . . . . . . . . . . . . . . 152 4.34 Slab model of QE as a function of X-ray energy . . . . . . . . . . . 154 6.1 Background-subtractedX-raylightcurveofXMMUJ063259.3+054801 from Swift-XRT observations . . . . . . . . . . . . . . . . . . . . . . 167 6.2 Lomb-Scargle periodogram of Swift-XRT data . . . . . . . . . . . . 168 6.3 z-transformed discrete correlation function as a function of time lag 169 6.4 X-ray light curve of XMMU J063259.3+054801 folded over the pro- posed period of 321 days . . . . . . . . . . . . . . . . . . . . . . . . 170 A.1 Carriage frame from Ralph A. Hiller Company . . . . . . . . . . . . 173 A.2 Detector module frame from Ralph A. Hiller Company. . . . . . . . 174 A.3 Detector module breadboard. . . . . . . . . . . . . . . . . . . . . . 175 A.4 Detector pedestal bottom plate. . . . . . . . . . . . . . . . . . . . . 176 A.5 Detector pedestal side strut. . . . . . . . . . . . . . . . . . . . . . . 177 A.6 Detector pedestal top plate. . . . . . . . . . . . . . . . . . . . . . . 178 A.7 Liquid nitrogen vessel . . . . . . . . . . . . . . . . . . . . . . . . . . 179 A.8 Henke tube source port plate . . . . . . . . . . . . . . . . . . . . . . 180 A.9 Port plate containing all of the QE test stand feedthroughs . . . . . 181 A.10 Spacers that allow attaching the fluorescent target wheel to the Henke tube source port plate . . . . . . . . . . . . . . . . . . . . . . 183 A.11 Top, the source port plate. Bottom, the source shutter. . . . . . . . 184 A.12 The source holder rod and shutter rotational feedthrough shaft. . . 185 A.13 The source shield. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 186 A.14 An exploded view of the source plate. . . . . . . . . . . . . . . . . . 187 A.15 Proportional counter window plate. . . . . . . . . . . . . . . . . . . 188 B.1 Schematic of the 4-channel heater power supply. . . . . . . . . . . . 192 B.2 Heater power amplifier top surface silk screen. . . . . . . . . . . . . 193 B.3 Heater power amplifier top copper trace deposition. . . . . . . . . . 193 B.4 Heater power amplifier upper inner power plane. . . . . . . . . . . . 194 B.5 Heater power amplifier lower inner ground plane. . . . . . . . . . . 194 B.6 Heater power amplifier bottom copper trace deposition. . . . . . . . 195 B.7 Difference amplifier configuration . . . . . . . . . . . . . . . . . . . 196 B.8 Schematic of the 6-channel RTD current source. . . . . . . . . . . . 197 x