Dave Gaskell stopped by and let us know that given the cryo-touble in the North linac he and Yves Roblin are going home. They were about to try to thread the beam through the Compton chicane when the "cold box" of the North Linac gave up. Apparently there are (at least) two cold boxes in the CHL each one of them supplying one linac.
The Compton exercise will not happen today.