A NANOSECOND COAXIAL TARGET WITH ADJUSTABLE GRID FOR PULSED PROTON AND HEAVY ION BEAMS

The waveform of the beam pulses measured by a coaxial target is carefullystudied versus the ratio of the ion transit time to the duration of the beam burst.Other factors involved in the design of a fast response target are also discussed.A coaxial target with adjustable grid-target gap is then designed and constructedto fulfil the pulse measurements for various ions. The rise time of the target isdetermined to be 0.2 ns. Beam bursts of H~+, N~+, N_2~+ and Ar~+ with velocitiesranging from V/C=6.5×10~4 to 2.5×10~(-2) are measured successfully with thetarget. The results are well consistent with the design values.