Microdosimetry Electronics for USNA Satellite: Midstar

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Microdosimetry Electronics for USNA Satellite
Midstar

• MIDN 1/C Roger Callahan
• Mentors James Ziegler, ECE
• Vincent Pisacane, AE

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Background

• Human Space Exploration Mars in 2014
  ??

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Limitations

• Time of Flight (24 36 months?)
• Supplies (need to manufacture water on Mars?)
• Bone Strength (2 loss/month)
• Radiation Exposure (will all 7 Astronauts
  survive?)

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Remedies

• Improved propulsion (faster flight)
• Research in bone loss (prophylactics available?)
• Research in Cosmic Radiation
• Source of Astronaut Exposure
• Shielding Outside and Inside Radiation
• Omission of Local Radiation Sources

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Cosmic Radiation

• Spacecraft Material Effects
• Amount and Type of Radiation
• Effects on Body

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DNA Structure
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Detector Placement in Satellite
Phantom to simulate effects of human body
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Micro-Dosimetry Detector
--- Active Volume ---
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Diode Array (100,000 on Chip)
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Output

• Femto-Coulomb charge pulse ( 6000 e-)
• Preamplifier converts Charge Pulse to a
  proportional Voltage Pulse

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Signal Processing

• Extract noise, filter relevant data (Pulse
  shaping)
• Differentiation High Pass Filter
• Integration Low Pass Filter
• Send to Multi-Channel Analyzer to digitize and
  store spectrum of pulses (see later).
• MCA Buffers to Communications for Download and
  Operational Commands.

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Signal Processing
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Signal Processing
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Multichannel Analyzer Amptek MCA8000A

• Pocket MCA
• 128 channel spectrum
• 2 Meg Memory
• RS-232 Connector (I/O Interface)

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Power

• 30mW -Detector and Preamp
• 250mW Signal Processing
• lt 300mW - MCA
• 600mW Total (12V DC)

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MCA Side Views
Computer Interface
Interface DB-9 male RS-232 connector Power
3.5 mm x 1.3 mm female barrel connector Input,
Gate 1, Gate 2, LEMO, S series receptacle, style
00, female
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Timeline
EE-414 Design Project

• January Detector (Background, Operation, Signal
  Processing
• February Signal Processing (Converting charge
  pulse, Improving S/N, Background Subtraction).
• --- Requires HARDWARE!! --
• March Construction of Radiation Spectrum,
  Understanding Physics
• April System Integration, Field Testing, Final
  Report