Detection of gamma rays at inertial fusion facilities using gas Cherenkov detectors

When?

Tuesday 4 October 2011, 14.00

Where?

30 BB 03 Physics Seminar Room

Open to:

Staff, Students

Speaker:

Mike Rubery, AWE

Inertial confinement fusion (ICF) is an area of experimental physics involving the implosion of capsules containing hydrogen isotopes to the required temperatures and densities for fusion using lasers. Energy from the laser is coupled to the capsule surface, ablating outer material whilst simultaneously driving shock waves and material inward to a stagnation region where temperatures, pressures and confinement are appropriate for fusion. To diagnose the implosion many detectors are used generally measuring radiation from the capsule as a function of energy, time or space. This talk will discuss the gas Cherenkov detectors fielded at the NIF and Omega facilities to record low intensity DT fusion gammas; the purpose being to report the temporal reaction history and FWHM of the implosion. Benefits include: thresholding where only gammas exceeding a minimum energy are observable due to the dielectric properties of the gas, reducing sensitivity to low-energy background radiation; and preservation of the reaction history structure at large standoff distances, an issue for particle diagnostics.