REPORT FOR ANALYTICAL CHEMISTS
Handle your high vacuum on a LOW BUDGET... Figure 3. Alpha Scattering Spectrum of Potassium Carbonate
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step is negotiated and the experimental· agrees to deliver a working breadboard model, (not flight-hardware) to the cognizant NASA technical authority, for testing. Analytical integrity, operating life, reproducibility, and reliability are examined in various environments. Next step in the chain of events leading to space, is the construction of a prototype of the flyable instrument. This is basically an engineering step to "space-harden" and reduce weight of the instrument. The experimenter may submit a proposal to handle this phase of the operation, but because of the specialized techniques involved, this step is generally contracted to a "space hardware" firm. Prototype instruments are space tested as outlined above. If everything is satisfactory, NASA contracts with industry to provide a specified number of units and they are placed in ready. The last step is an administrative decision from the cognizant program office. This is where the compromise in desired information is made to conform to weight and power limitation of a given flight. At the present time, there are a variety of analytical instruments, at one stage of development or another, being actively considered. A fair sampling of these instruments is listed below. Alpha Particle Scattering Alpha particle scattering
for
chemical analysis of lunar surfaces was proposed to NASA by Professor A. Turkcvich at the University of Chicago (74). On the basis of this proposal, Professor Turkevich received a NASA grant to develop the technique and build a breadboard model for testing by the Jet Propulsion Laboratory. Dr. E. Franzgrote at J P L is NASA's in-house cognizant authority for this program. Professor Turkevich has also been supported by the personnel of the University of Chicago, Laboratory for Applied Science, Argonne National Laboratory, and J P L . The scientific objective of this experiment is to determine the amounts of all major elements present (greater t h a n a few per cent) except hydrogen. Individual elements through atomic number 20 will be determined. Elements with triasses above 40 will be identified in mass groups. For example, iron, copper, and nickel will be reported as one group. Expected accuracy is roughly the reciprocal of the percentage observed. Instrumentally, the experiment contains a source of 6 m.e.v. alpha particles, solid-state surface barrier detectors, amplifiers, and two 128 channel pulse height analyzers. Principle of operation involves bombardment of the sample material by the alpha particles with the subsequent detection and measurement of the scattered alpha par-
