b'Developing Tools to Advance Earth Science 24Filament To C arnegie researchers often design and build instruments to pursue new scientific Mass questions. Few other organizations foster Spectrometer this capability. Geochemist Rick Carlson, with postdoctoral associate Jesse Reimink, is designing and building a new type of mass spectrometer. This Earth-science workhouse determines a samples The drawing above shows a schematic of the cavity of the newcomposition by creating ions, atoms with an electric mass spectrometer that is shown in the photo at top. Samplecharge, and then separating the ions by mass. The atoms (grey balls) are loaded into the cavity, which is then heatednew design could increase sensitivity by 10-40 times, by electrons emitted from the filament (the glowing loop in the photo). The heating causes the cavity to glow and sample atomsdepending on the element, to allow the measurement to evaporate and bounce against the walls of the cavity until theyof smaller samples or much higher isotope ratio become positively ionized, after which they are extracted into theprecision on currently used sample sizes. Isotopes mass spectrometer (to the right in the drawing and photo). Top image courtesy Rick Carlson, Carnegie Institution for Science; bottom image courtesy Jesse Reimink, are versions of the same element that have different Carnegie Institution for Science mass. The isotopic composition of an element can serve as a chronometer when it is changed by radioactive decay that occurs at a constant rate.'