WEAVE Spectrograph

This is a two-arm multi-object spectrograph mounted on the William Herschel Telescope. Each arm contains a two-chip mosaic of E2V 6k x 6k CCDs. I was contracted to design and build preamplifiers, upgrade the cabling and rewrite the controller software. Since the preamplifiers were operated in a vacuum , good thermal design was crucial.

Weave 72MPix focal plane

WEAVE 8-channel preamplifier mounted in the CCD cryostat with all cables attached.

Four-layer preamplifier PCB design. Manually laid out and routed using Altium Designer

Three PCBs were manufactured. Rear surface gold plated to reduce thermal coupling to CCDs.

Thermal test rig used to prove thermal design. The PCB cooled to 273K when off, and warmed up to 285K when operating (Photo Andy Ridings, ING)

Preamplifier design tested with a warm engineering CCD prior to installation in instrument.

Photon transfer behaviour of one of the CCDs. Read noise was between 2.2e and 2.7e RMS.

Weave project Page