The detector mount design passed a critical design review. However, because of the importance of maintaining a detector stability of 0.1K, it was decided to more precisely model the thermal time constant of the mount and closed-cycle cooler circuit. Fabrication of the detector mount is scheduled for next quarter.
Lab testing of Hall Effect sensors for cryogenic position sensing, demonstrated reproducibilities of 10 microns compared to 100 microns for mechanical limit switches. As a result SpeX will employ Hall Effect sensors on the high precision grating and prism turret.
Most of the SpeX electronic boards (array fanout, array configuration, 61-pin hermetic connector, and clock/bias boards) are now designed, PCB layout finished, and boards delivered. Board components have been ordered and stuffing will start next quarter. One of the DSP boards has been successfully integrated with the SPARC engine (Big Dog 1) and, using the DSP Development toolkit, software development begun.
A PAIDAI 1024x1024 bare multiplexer was delivered to us in March. Continuing work on the array controller and detector mount should allow us to run the multiplexer in the SpeX lab test dewar by July. Processing of InSb wafers for PAIDAI continued smoothly at SBRC during this quarter. The first of at least eight hybridisation for PAIDAI is scheduled for May. This may be delayed if prior SBRC hybridisations for other projects encounter problems.