High Current Proton Tests of the Fermilab LINAC

The peak current limit for the Fermilab Linac was recently studied. The purpose was to learn what components of the present Linac can be used for the first stage of a proposed proton driver[1]. For this application the Linac must provide a H beam in excess of 5000 mAμsec per pulse. The original Fermilab Linac was designed for protons with a peak current of 75 mA and a pulse length of four Booster turns (~10 μsec). The high energy replacement was designed for a peak current of 35 mA and a beam pulse length of 50 μsec. The present H source cannot deliver more than ~80 mA which produces 55 mA in the Linac. Using a proton source allows the system to be tested to currents of ~100 mA and pulse lengths long enough to observe the effects of long pulses. This test has shown that the present Linac can accelerate beam having a peak current up to ~85 mA with beam loss comparable to the present Linac operation (~45 mA). The results of the test will be presented.