Two stage proton induction linac

The present thesis presents the investigation of a multi-megavolt, multi-kiloampere proton beam in a linear induction accelerator. The experiment investigated the two initial stages of such an accelerator. The injector stage produced a 1 MeV proton beam with current {dollar}sim5{dollar} kA and a pulse width of 50 ns. A second accelerating gap increased the beam energy by {dollar}sim300{dollar} keV.; The beam was generated in a radial magnetically insulated diode. The beam propagated to a second accelerating gap through a drift region, immersed in an axial magnetic field. In both the diode and in the second gap the magnetic field had a full cusp geometry.; Beam transport between the gaps was {dollar}sim70{dollar}% efficient for vacuum propagation. In the drift region the beam diverged 4{dollar}spcirc{dollar} due to the radial electric field induced by the positive ions. Efficient transport between the gaps depends on space charge neutralization. The neutralization is sufficient to transport the beam to the second gap if background gas or a fast opening puff valve is used. The beam divergence in the drift region with gas neutralization is below 1{dollar}spcirc{dollar} and the transport efficiency is 99%(+1%/{dollar}-{dollar}25%). The annular proton beam profile is maintained to the second accelerating gap.; The beam divergence under vacuum conditions was {dollar}sim4spcirc{dollar}, which suggests that a radial electric field of 19 kV/cm at the beam outer radius was present. Such an electric field is caused by a beam space charge neutralization of 98%. Injection into the puff valve system shows that the beam divergence is 0.8{dollar}spcirc{dollar}. This implies that the maximum radial electric field is {dollar}{lcub}sim{rcub}3{dollar} kV/cm. This value of radial electric field implies that, under these conditions, the beam space charge is effectively neutralized to within 0.03%.; The beam profile and the transport efficiency across the second gap depend strongly on the conditions in the gap region. In the case of the gas filled gap, the transport efficiency is {dollar}{lcub}sim{rcub}100%{dollar} and the beam divergence is below the resolution level. With a plasma filling this region, however, it is not possible to apply the 300 kV pulse without shorting the accelerating gap.; For vacuum conditions in the second gap the transport efficiency is 71%({dollar}{lcub}pm{rcub}13%{dollar}) without the applied voltage, and 86%({dollar}{lcub}pm{rcub}5%{dollar}) when a 300 kV pulse is applied. The beam divergence under both conditions is {dollar}{lcub}sim{rcub}1.6spcirc{dollar}.; The relatively poor transport efficiency across the second gap and the increased beam divergence limit the energy achievable in a multistage device.