1. 2010 Olin Student Projects Keith Gendreau Keith.c.gendreau@nasa.gov 301-286-6188 Fred Huegel frederick.g.huegel@nasa.gov 301-286-2285 Kurt Rush Kurt.d.rush@nasa.gov 301-286-1196 Bob Baker Robert.g.baker@nasa.gov 301.286.9882

2. Olin student Project #2: Modulated X-ray Source Controller Our new modulated X-ray source uses UV light to generate photoelectrons which are accelerated into high voltage targets to make X-rays We like to have absolute control of the X-ray flux, which is driven by absolute control of the UV light (from LEDs) Olin student project: build an X-ray source electronics box which –provides HV –Drives UV LED with arbitrary flux output –Measures currents, temperatures –Is USB controlled with PC or mac software

3. Characteristics: Rugged- no moving parts or fragile filaments- perfect for space flight. Modulates x-rays at same rate that one can modulate an LED Major NASA Uses: Timing Calibration A “flagged” in-flight Gain Calibration Source: Have calibration photons only when you want them and increase your sensitivity by reducing the background associated with the calibration photons The World’s First Fully Controllable Modulated X-ray Source

4. This has evolved to include an electron multiplier LED HV for Target (~5-10 kV) HV for Electron Multiplier (~2-3 kV

5. 1 st Magnum Multiplier MXS Multiplier HV Electron Target HV Be Window AMPTEK Detector Electron Target HV Multiplier HV

6. Output of AMPTEK Detector Pulses Modulating X-ray Output Some 1 st Data

7. Block Diagram Computer “Smarts” USB LED LED Driver HV Multiplier (DC/DC Converter) HV Target (DC/DC Converter) Source (provided by GSFC

8. Commands from computer HV target voltage (0-10 kV) –Use EMCO Q series dc/dc converter with a dac and transistor follower HV multiplier voltage (0-3 kV) –Use EMCO Q series dc/dc converter with a dac and transistor follower Arbitrary LED flux as a function of time –Asci file? Pulsed LED flux –Frequency, duty cycle or width, amplitude Query for housekeeping

9. House Keeping Items LED current (average, max) LED temperature (necessary?) HV current (or atleast current and voltage into various DC/DC converters)