Photon burst mass spectrometry for the measurement of {sup 85}Kr at ambient levels

Photon Burst Mass Spectrometry has been used to measure {sup 85}Kr in a sample with an abundance of 6 x 10{sup {minus}9}. Improvements in detection efficiency by the use of avalanche photodiodes cooled to liquid nitrogen temperature are reported, which should make possible measurement of {sup 85}Kr at the ambient atmospheric abundance of 10{sup {minus}11}. Potential applications include nuclear monitoring, atmospheric transport, and dating young ground water up to 40 years

The Askey scheme as a four-manifold with corners

Racah and Wilson polynomials with dilated and translated argument are reparametrized such that the polynomials are continuous in the parameters as long as these are nonnegative, and such that restriction of one or more of the new parameters to zero yields orthogonal polynomials lower in the Askey scheme. Geometrically this will be described as a manifold with corners