DARHT-II energy analyzer

A energy analyzer system is being built for the DARHT-II accelerator similar to the energy analyzer used on the Astron accelerator. This system consists of a scattering wire, magnetic bend, and signal detector. The wire thickness of 40 mil carbon and the scattering angle of 11 degrees is chosen for good signal to noise ratio. The dipole bend angle is 60 degrees, with a 30 cm radius of curvature. The image-plane focal distance is chosen for the required energy resolution. The energy resolution and acceptance are 0.1% and ±5% with a time response of 10 nsec. The wire must survive the 2 usec 2 kA, 18.4 MeV DARHT-II beam. The MCNP code was used to study the wire scattered properties. The scattered beam fills the available 1×2 cm dipole aperture. The dispersion normal to the beam direction is 0.43 cm/%. The detector is a PIN diode array which determines the beam position on the chip. This array consists of 40 2.5×0.1×0.25 mm bins with a gain in excess of 10000. The system will be installed in the space between the debris blocker and the cruncher solenoid up-stream from the shuttle dump.