US 7,589,529 B1
	Method of and apparatus for in-situ measurement of degradation of automotive fluids and the like by micro-electron spin resonance (ESR) spectrometry
James White, San Francisco, Calif. (US); and Christopher White, Palo Alto, Calif. (US)
Assigned to Active Spectrum, Inc., San Carlos, Calif. (US)
Filed on Oct. 31, 2006, as Appl. No. 11/590,522.
Claims priority of provisional application 60/736264, filed on Nov. 14, 2005.
Int. Cl. G01V 3/00 (2006.01)

U.S. Cl. 324—316  [324/306]

19 Claims

1. An electron spin resonance spectrometer having, in combination, a broadly frequency-swept tunable high-Q microwave cavity resonator provided with a fluid inlet and an outlet for passing a fluid sample through the resonator during the resonating of the cavity resonator by microwave energy in order to effect absorption or dispersion of the microwave energy in the sample, wherein the cavity resonator is disposed in an external uniform permanent magnet field of sufficient intensity to cause magnetic resonance in the sample within the range of frequency sweeping.