Gamma Spectrometer

	LP gamma-ray spectra. LP gamma-ray spectra plotted as number of counts per 32 seconds versus energy. The top panel shows an average of spectra collected during the first five months of the mission. The bottom panel shows spectra taken for two different lunar regions. The plot for the Imbrium Region is from 30W to 10W and 20N to 40N within Mare Imbrium. This region is known for being unusually rich in basalts and KREEP. The plot labeled Joule Region is from 150W to 130W and 15N to 30N. The Joule crater (located at 145W, 25N) is located in the lunar highlands which are mainly anorthositic. Lawrence et al., Science, 281, 1484, 1998.
	Thorium Counting Rate Map. Color coded map of the log of the thorium counting rate as measured by the LP GRS. The bottom panel shows a Mercator projection for latitudes of 45S to 45N and the top panel shows stereographic projections for latitudes of 45N,S to 90N,S. The data is binned into equal area pixels which have a size of 5° latitude by 5° longitude at the equator. Contours of albedo data taken from Clementine data are shown for latitudes between 70S and 70N. Lawrence et al., Science, 281, 1484, 1998.
	Potassium Counting Rate Map. Map of the log of the potassium counting rate as measured by the LP GRS. The bottom panel shows a Mercator projection for latitudes of 45S to 45N and the top panel shows stereographic projections for latitudes of 45N,S to 90N,S. The data is binned into equal area pixels which have a size of 5° latitude by 5° longitude at the equator. Contours of albedo data taken from Clementine data are shown for latitudes between 70S and 70N. Lawrence et al., Science, 281, 1484, 1998.
	Thorium Counting Rate Map. Lunar nearside and farside orthographic maps of the log of the thorium counting rate. The nearside map is centered on Mare Imbrium and the farside map is centered on the antipode to Mare Imbrium. This projection shows that the farside Th maximum is very close to the antipode of the local minimum within Mare Imbrium. Lawrence et al., Science, 281, 1484, 1998.
	Th Distribution from the Imbrium Impact Point. The highlands Th distribution as a function of distance from the Imbrium impact point from the LP GRS data (closed circles) and the model curves of Haskin. The upper and lower model curves are based on the largest (485 km) and smallest (335 km) estimation of the Imbrium transient crater and are calculated as the percentage of primary material ejected from Imbrium. Lawrence et al., Science, 281, 1484, 1998.
	Potassium and Thorium Distributions. Plot of potassium counting rate versus thorium counting rate as measured by the LP GRS. Lawrence et al., Science, 281, 1484, 1998.
	Thorium Counting Rates and Ground Truth. Plot of measured LP thorium counting rates versus derived soil abundances in parts per million (ppm) for various landing sites. The soil measurements vary between minium and maximum estimates. The LP measurements are taken from the 150 by 150 km pixel covering each landing site. The uncertainty of the LP mesurements is approximately the size of the plotting symbols. Lawrence et al., Science, 281, 1484, 1998.
	Iron Counting Rate Map. Map of the iron counting rate as measured by the LP GRS. The bottom panel shows a Mercator projection for latitudes of 45S to 45N and the top panel shows stereographic projections for latitudes of 45N,S to 90N,S. The data is binned into equal area pixels which have a size of 5° latitude by 5° longitude at the equator. Contours of albedo data taken from Clementine data are shown for latitudes between 70S and 70N. Lawrence et al., Science, 281, 1484, 1998.