TRIFFID Photometre 

First light: June 1992.

Last commissioning: 

Designed and built by: Department of Physics, National University of Ireland, Galway.

Description: This photometer goes on several telescopes around the world, including WHT (Cassegrain and Nasmyth - GHRIL - focus). An array of dichroics splits up the incident beam in broad band regions, each region projected onto the detector. The photon-counting tube detects each photon arrival by knocking of an electron (photo cathode) which is accelerated through an electric field until it hits a micro channel plate which produces a shower of electrons. This shower is detected on a fine grid of wires and, using a techique called coincidence logic, the photons xy position is recorded together with the arrival time. The two-dimensional image builds up on the 'MAMA' display. Furthermore, 3 fibres acts like single channel photometers (ADC). Detector size is ~ 1000 x 200 'resolution elements'. Each element is 24 microns corresponding to 0.1" on sky. Field of view is ~ 100" x 20" 

Some scientific highlights:

• Enhanced optical emission during Crab giant radio pulses (2003)