RxW

Progress on RxW was slow during the autumn owing to a difficulty in achieving adequate cryogenic temperatures at the mixer. That problem was eventually solved and since New Year's progress has been very good. The MRAO staff have installed and cooled all four mixers in the main RxW cryostat. The receiver noise temperatures of the 450-500 GHz mixers (C-Band) are about 100 K (DSB) and the 630-710 GHz (D-Band) mixers yield about 500 K (DSB). RxW is essentially complete now with the optics assembly, the control electronics, and the mixers installed and functional. Some work remains in the software area.

The MRAO staff are now testing and characterising the receiver in the laboratory commissioning phase. The tests include measurements of beam patterns, tuning parameters, noise temperatures across the tuning bands, sideband rejection characteristics, and computer control of the instrument. Pending the results of the first phase of lab commissioning, we have not yet set a firm date for shipping the receiver to Hawaii. If no serious difficulties develop, the lab commissioning should proceed for about another two months and the receiver should be available for telescope commissioning by the early summer.

P. R. Jewell

18th March 1997

for Semester 97B

The commissioning dates for RxW are provisionally set for late in semester 97A. Unfortunately, the dates will be after the regular PATT deadline and after the ITAC meeting which will be awarding time during semester 97B. It will not be possible to accept applications which specifically require the features and sensitivities of the RxW instrument. Therefore the D-band (690 GHz) section is not available for semester 97B. C-band observations can be applied for assuming that the project can be completed using the existing RxC2. If, and when, RxW is commissioned, all outstanding C-band applications will be transferred to use the new instrument.