Accession Number : AD0610100

Title :   DEVELOPMENT OF QUADRUPOLE MASS SPECTROMETER.

Descriptive Note : Rept. for Jun 63-Nov 64,

Corporate Author : MASSACHUSETTS INST OF TECH CAMBRIDGE LAB FOR INSULATION RESEARCH

Personal Author(s) : Woodward,C. E. ; Crawford,C. K.

Report Date : DEC 1964

Pagination or Media Count : 59

Abstract : An electric quadrupole mass spectrometer has been developed to cover 1 to 400 amu in four ranges. The electronic circuits that supply voltages to the mass filter are capable of 50:1 spectral-range sweeps in 0.1 sec, but resolution over a wide sweep range is limited by nonlinearity in the control of the r-f voltage. Compensation reduces nonlinearity over a 10:1 sweep range from 4 to 0.4%. The electron-multiplier ion collector is operated as a particle detector to eliminate the effects of multiplier gain variations. High-speed circuits (resolving times < 5 x 10 to the minus 8th power sec) produce standard output pulses that are integrated in a linear ratemeter to determine the mean rate. Spectrometer resolution is limited by mechanical imperfections in the quadrupole lens: The highest observed value has been m/delta m = 300 measured at the 1% amplitude points. A fine structure on the mass lines is attributed to lens imperfections . (Author)

Descriptors :   (*MASS SPECTROSCOPY, SPECTRUM ANALYZERS), (*SPECTRUM ANALYZERS, MASS SPECTROSCOPY), CIRCUITS, RESOLUTION, RADIOFREQUENCY, ION BEAMS, ION SOURCES, VOLTAGE, ELECTRON MULTIPLIERS, SWEEP GENERATORS, RADIOFREQUENCY LENSES, GAIN

Distribution Statement : APPROVED FOR PUBLIC RELEASE