Tara took a BRDF measurement yesterday of AlGaAs mirror #114.
In this measurement, the return beam is dumped using black anodized foil instead of a razor blade dump. This seems to make the peak at 20° disappear, and now we get a more or less monotonic falloff in scattered power.
TIS from 14° to 71° is 39(6) ppm.
Data and code are on the SVN at CTNlab/measurements/2014_07_30.