Proposal for a Source of Polarized Protons

Abstract

In a cyclotron, protons are produced by ionizing hydrogen atoms in the center of the magnet. If these atoms arrive in the ionizing region in states where the component of the proton spin along the field (I/sub 2/) has one value only, say +1/2, completely polarized protons could be available for acceleration. The variation of the four energy levels of a hydrogen atom, a(M/sub I= 1/2) and b(M/sub I =-1/2) E positive and c(M/sub I =-1/2/) and d(M/sub I/ = 1/2) E negative, as a function of the applied field is shown. It is relatively easy to separate, in an incoming beam of unpolarized hydrogen atoms, with a Stern-Gerlach device, those in states a and b from those in states c and d because of the large difference in magnetic moment. In the present proposal, once a beam of atoms distributed with equal populations between the states a and b has been obtained by a Stern-Gerlach device, all atoms in the b state are transferred into the d state by means of a radiofrequency field H/sub 1/ cos omega t parallel to the field H /sub 0/, by the adiabatic passage method. All proton spins are then in the statemore » I/sub 2/ = +1/2. (W.D.M.)« less