From: "Akira Konaka" Subject: Re: UCN white paper comments and phone call tomorrow Date: Wed, September 5, 2007 6:13 pm To: "Jeffery William Martin" Cc: cymru@triumf.ca,trlr@triumf.ca,ewb@triumf.ca,"Rick Baartman" ,schmor@triumf.ca,krab@triumf.ca,dutto@triumf.ca,masuda@post.kek.jp,spage@cc.umanitoba.ca,"Nigel Lockyer" ,vanoers@jlab.org,mgericke@jlab.org,amicherd@nuclear.uwinnipeg.ca Hi. I had a chat with Rick Baartman. He thinks that Chuck's option would work in the same way. The concern that Rick has in his two component beam scenario is the level of beam halo. If it is 1% or 1uA, the radiation level would be too high. A collimator is required in the cyclotron vault for 1uA beam would be a serious challenge. The thin stripper foil, which is currently developed, may give less beam halo and work. There is another option came up during the discussion in achieving two component beams for BL4N by separating the beam in time: [10msec of ISAC] [1msec off at the ion source] [10msec for UCN] [1msec off] During the 10msec ISAC period, the kicker direct the beam to ISAC. During the 10msec UCN period, the kicker magnet direct the beam towards ISAC beam dump. Beam is kicked towards UCN target 1minute every 4minutes if it is within the 10msec UCN period. Otherwise, it will go to the ISAC beam dump. Kicker magnet is turned on/off during the 1msec periods when ion source is off. This does not require double component beam but rather UCN and ISAC beams share times. This may be simpler from the operation point of view. Rick, please correct me if I make misunderstandings. - Akira