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The non-buttable chip is not of great interest to us, since one of our desires would be to construct a mosaic for the WHT PF. Pennypacker is providing this sort of chip for the INT PF, where the emphasis is on using an established device, which has already been thinned (by Lesser).
The 2-edge buttable chip is of interest. However the fact that it comes in two variants means that the effective yield is lower. We note (see below) that Lesser has not yet successfully thinned and packaged one of the 2-edge buttable chips.
The 3-edge buttable chip would seem the best option for this format. The chips are all identical, and therefore yield/choice of chips should be higher. The 3-edge version is a new design, and the first batch (October 93) appears to have produced a good yield.
Only one (or two?) batches of chips have been made. NOAO (see below) report that they need a preflash, which is a particular disadvantage for a spectroscopic chip.
The chip is new, and being made now (one batch).