2010 Olin Student Projects Keith Gendreau [email protected] 301-286-6188 Fred Huegel...
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Transcript of 2010 Olin Student Projects Keith Gendreau [email protected] 301-286-6188 Fred Huegel...
2010 Olin Student Projects
Keith Gendreau
301-286-6188
Fred Huegel
301-286-2285
Kurt Rush
301-286-1196
Bob Baker
301.286.9882
2009 Student Projects with contacts
• XACT Sounding Rocket Low Voltage Power Supply Point Design– Keith Gendreau, Kurt Rush, Fred Huegel, Bob
Baker
• Modulated X-ray Source Controller– Keith Gendreau
Project #1, XACT Low Voltage Power Supply Point Design
• We are in the initial phases of designing and building a suborbital rocket payload to do astrophysics
• The detectors and command & data handling units need regulated low voltage power derived from “28 Volts” from Rocket battery
• Do a point design of a Low Voltage Power Supply (LVPS) and build a prototype– Take Electrical and mechanical requirements of LVPS– Include basic housekeeping functions– Build a command tester
XACT Payload and Rocket
X-ray Concentrators & Star Tracker
Optical Bench
X-ray Polarimeters, Electronics, & MXS
Overall Payload Length: 3.26 mPayload Diameter: 52 cm*
Payload Mass: 80.2 kg (include ST)A 1st approximation of complete XACT rocket
Black Brant VC
Terrier Mk70
Aft Cone & Door
Nose Cone & Recovery System
Telemetry and ACSSystems
Very Basic XACT Block Diagram
Rocket Avionics System
Unregulated 28 V powerUnregulated 28 V power
Telemetry InterfaceTelemetry Interface
XACT Main Electronics Node (XMEN)
SRIB
LVPS
Regulated power
HK
PEB 1
PEB 2
HVPS
Regulated power
PEB 3
IN FLUX..Will define, but may be a bit bigger
Other details• We will soon specify connectors for the power
output and HK address and data• HK should include actual voltages and currents
and some temperatures of items which may get warm
• Look in digikey and elsewhere for cheap, but robust converters and parts..– Some specify shock and vibration ratings
• Can you make a USB based card that would allow us to query for HK?
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
Vacuum Flange
Electron Target
Photocathode
LED: Modulate This tomodulate the x-rays.
OpticalPhotons
X-ray Photons
Photoelectrons
10 keV or more
•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
This has evolved to include an electron multiplier
LED
HV for Target(~5-10 kV)
HV for Electron Multiplier(~2-3 kV
1st Magnum Multiplier MXS
Multiplier HV
Electron Target HV
Be Window
Be Window
AMPTEK Detector
Electron Target HV
Multiplier HV
Output of AMPTEK Detector
Pulses Modulating X-ray Output
Some 1st Data
Block Diagram
Computer
“Smarts”
US
B
LEDLED Driver
HV Multiplier (DC/DC Converter)
HV Target (DC/DC Converter)
Source (provided by GSFC
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
House Keeping Items
• LED current (average, max)
• LED temperature (necessary?)
• HV current (or atleast current and voltage into various DC/DC converters)
“i-Heliograph”
• Can we make a low power data transmitter to send “lots” of data from the moon to the earth using a 19th century idea enhanced with 21st century technology?
• How does such a system compare to laser communication?
Replace this guy with a high speed optical modulator and an ethernet port.
Replace this guy with a avalanche photodiode and an ethernet port..
Replacing the guy wiggling the mirror
• Voltage Controlled LCD displays (KHz Speeds?)
• Acoustic Optical Modulators (speeds up to 100 MHz)
Replacing the guy using his eye to see the signal on the
receive end• Avalanche Photo diodes
There should be a power savings compared to Laser
Comm• Lasers are ~10% efficient on producing
optical output from electricity it gathers from ~25% efficient solar cells.– Total efficiency from sun = 0.25 * 0.1 =
2.5%
• Mirrors are ~90% reflective
Other factors in comparison
• Mass to moon– Do solar cells and power system with
Laser weigh more than a mirror and heliostat?
• Reliability– Solar panels, motors, AOMs…– Is dust an issue?
2009 Olin Job
• Build a Heliostat to capture the sun• Pipe the light from the Heliostat through
either an accoustic optical modulator or a LCD retarder
• Build a simple pulse frequency modulator to drive the AOM or LCD retarder
• Build a demodulator to read the output of an APD
• Predict performance and compare to Laser Comm.
GSFC will provide
• A telescope base to make a heliostat• An AOM to modulate light• A Circuit design to produce a FM Pulse
train• A Telescope for the receive end• An APD (maybe dual use the one for
the MCA project)• The demodulator design.