1. Cosmic Ray Telescope for the Effects of Radiation (CRaTER): CRaTER Science Overview
Lunar Reconnaissance Orbiter
CRaTER Critical Design Review
Harlan E. Spence (CRaTER PI)

2. LRO Measurement/Science Overview
LRO Science Summary presented at Mission PDR – March 206 (from LRO Project Scientist, G. Chin’s presentation)

3. CRaTER Science Motivation
Galactic Cosmic Rays (GCR) and Solar Energetic Particles (SEP) have sufficient energy to penetrate shielding and deposit energy inside an astronaut = crew/mission radiation safety enroute to or on surface of Moon or Mars
Biological assessment requires not incident GCR/SEP spectrum (available on other mission satellites), but lineal energy transfer (LET) spectra behind tissue-equivalent material
LET spectra are an important link, currently derived from models; experimental measurements required for critical ground truth – CRaTER will provide this key data product
27 June 2006
Science Overview

4. Measurement concept unchanged since PDR
Two-ended solid-state, particle telescope with TEP views both zenith and nadir
Sensitive to GCR/SPE primaries and secondaries
(from original CRaTER proposal)
27 June 2006
Science Overview

5. CRaTER Telescope Configuration High LET detector Low LET PDR CDR
Moon
Space
CRaTER Telescope
Configuration
Nadir
High LET
detector
Low LET
Basic concept unchanged since PDR
Three, High/Low LET detector pairs bracket cylinders of tissue-equivalent plastic (TEP)
PDR CDR
Zenith
27 June 2006
Science Overview

6. CRaTER Science Goals
Primary zenith LET spectra constructed separately for GCR/SEP (unchanged since PDR)
Observations sorted according to lunar phase, LRO orbit phase, and sub-s/c lunar coordinates in order to quantify radiation environment (unchanged since PDR)
Will explore GCR variability from short (<days) to longer-time scales (> year) and rapid evolution of SEP events (unchanged since PDR)
Secondary science (CR/lunar surface interaction) from nadir observations - better quantified since PDR, no impact to primary science
27 June 2006
Science Overview

7. Primary Science Team Activities Since PDR
Instrument Modeling SRIM, GEANT4, BBFRAG, HETC-HEDS, FLUKA, HZTRAN
Ion Beam Validation
12 September 2005 Detector prototype characterization at LBNL 88” cyclotron
22 January 2005 TEPTA response to p+’s at MGH proton accelerator ( MeV)
13 March 2006 Prototype detector/TEP characterization at LBNL (light ions)
19 March 2006 Dry run at MGH as prep for BNL run
27 March 2006 TEPTA response to heavy ions at BNL (56-Fe, 1 Gev/n) – >~4 hours of beam time
Collaborations NASA/JSC Space Radiation Analysis Group has supported one beam run (BNL); negotiating access to CRaTER data
27 June 2006
Science Overview

8. Modeling Example: 1 GeV/nuc Fe
State-of-the-art in-development physics codes used for most complex interactions (energetic heavy ions) – these are codes that CRaTER data products will ultimately improve
HETC-HEDS & BBFRAG (courtesy C. Zeitlin), see example below, constrain extremes
Lab validation of TEP test apparatus and E/M unit in available ion beam facilities
Detailed theory/model comparisons underway
27 June 2006
Science Overview

9. Beam Run Example: BNL/NSRL - March 2006
D1 D TEP D3 D4
2-D histogram of all coincident events between D1/D4
Rel. Energy deposited
in D4 (low LET)
Rel. Energy deposited in D1 (high LET)
TEP test of 1 GeV/n iron
NASA/JSC/SRAG provided CR-39 for independent measurement of LET in support of CRaTER test – thank you!
27 June 2006
Science Overview

10. Post-CDR Science Team Activities
2-D histogram of all coincident events between D1/D4
Instrument Modeling Comparison of model predictions for beam run conditions with beam data (E/M and F/M)
Ion Beam Validation Detector calibration and system validation/verification at previously visited beam facilities (LBNL, BNL, MGH); access to these now-familiar facilities already in place – detailed schedules being worked
Collaborations Continued collaborations with NASA/JSC SRAG folks. They have provided valuable, unanticipated support that has added to our team’s capability. Access to CRaTER data supportive of SRAG’s NASA duties.
27 June 2006
Science Overview

11. 27 June 2006
Science Overview