Target Studies

Talks from the meetings of the European target and collector working group can be found on the ENG site.

Neutrino Factory Targets

Current (2005) neutrino factory designs call for a 4 MW (mean) proton beam of 2–30 GeV energy impinging on a heavy element target.  The beam is pulsed at 50 Hz with ~50 μs long macro-pulses consisting of one or more micro-pulses of ~1 ns length.

The target, 1–2 cm in diameter and 20 cm long, dissipates 1 MW (mean) and a dump target absorbs the remaining 3 MW of beam power.  The high power density causes problems with cooling a static target and the high energy density per pulse gives rise to severe thermal shock effect.

At present three target solutions are proposed

1. A mercury jet target which easily removes the heat.  The target is blasted apart by each beam pulse but reforms before the next pulse, thereby overcoming the thermal shock problem.
2. A solid target of small spheres to overcome the thermal shock problems, cooled by flowing helium or water.
3. A rotating toroidal ring operating at 2000 K, dissipating the heat by thermal radiation to water cooled walls.  The thermal shock is a problem which is presently being examined.