Hey Andrew,

Yes, that may be the powers-of-two (8, 16, 32) channel pattern that shows up in LET spectra.  The previous plot had 5-pixel smoothing.  Here it is with 17-pixel smoothing, which would cancel out the 16-channel pattern.  The low-energy features aren't there any more.



On 3/13/2019 10:50 AM, Andrew Jordan wrote:
Out of curiosity, is there a periodicity in the plot that's ~0.3 MeV "long"? It's most obvious at 4-5 MeV, but I can see it from 1 MeV to almost 6 MeV.



On 3/13/19 10:41 AM, Jody Wilson wrote:
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.


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-- 
Jody Wilson
Space Science Center
University of New Hampshire
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