An Assess~ment of the Effects of Radiation on Permanent-magnet Material

Electrons that are IOSI from the beam during nom-A operation of a synchrotron radiation source and during a beam dump at the end of 1 mn produce both ionizing radiation and neutrons. This radiation has the potentirl oi damaging sensitive maxials. in particular those that ne:rd to be very close to the beam. In the ~1, ‘ooiers and undulators for the .Wxnced Light Source (ALS) 31 LBL. magnetic materials such 3s the veq-high-performance neodymium-iron-boron uill be 3s close 3s I cm 3wny from the electron beam during operation. TINS mxctial. which is preferred because of its high rcmsnsnce. is known ‘o be more sensitive IO radiation than some other magnetic m;ltcrisls. Simple energy loss estimates and the EGSJ code were used to estimztr the radiation levels in the ALS insertion devices in the regions of the magnetic mzmxi~ls. The radiation levels were estimated for both aluminum and stanless steel vacuum chambers to determine if one would provide significantly better shis!ding. \Vs conclude that SVd-Fe-B can be used in the ALS insertion devices and that there is little difference in the radiation levels for aluminum 2nd stainless steel vacuum vessels.