Hi CRaTER folks,
A "work in progress" panel that I'll include in my LPSC poster next
week is a ratio of the whole-mission *mare* LET spectrum to the
*highlands* LET spectrum. The idea is that mare-rich elements
should make positive spectral features in this ratio, while
highlands-rich elements should produce dips in the ratio.
New since I last addressed this:
1) Wouter pointed out that gamma ray Compton edges should be more
prominent in our data than the primary spectral lines, since CRaTER
is not at all optimized to collect all of the energy from a given
gamma ray photon. So I'm only labeling the energies of the Compton
edges now.
2) Andrew and Wouter have been searching for new methods of
normalizing CRaTER data for making maps using combinations of
singles rates and the "linger time" of LRO over the Moon. Along the
way Andrew discovered that the lunar map of the raw D4 singles rate
looks kind of similar to the SEPI map (ditto the raw D6 singles rate
map), which means that whatever is lighting up the highlands in the
SEPI map is registering in D4 as well as D6. Therefore in the above
plot I've used the mare/highlands ratio from both D4 and D6 to
improve the signal.
Notes:
Silicon and oxygen should make the brightest features due to their
high overall abundance, but they're almost as abundant in the mare
as the highlands, so they should basically cancel out in this ratio,
and therefore I'm not labeling them.
--
Jody Wilson
Space Science Center
University of New Hampshire
---
Did you buy $ilver today?