0.8 mm Receiver

The IRAM 345 GHz SIS receiver already in operation last winter will be made available for a limited period of time. Its performances are:

• Operating band: 330 GHz - 360 GHz
• Image sideband rejection 4-6 dB
• Receiver temperature= 100 K (up to 345 GHz), 130-150 K above 345 GHz
• Feff= 0.8, Beff=0.17.

It can be operated either alone or, with some extra losses, simultaneously with 230G2 and 3mm2. The rejection of the image sideband reduces the contribution of the atmosphere to the system noise temperature and significantly lowers the latter. Although system temperatures lower than 500 K were recorded last winter with precipitable water vapour below 1mm, we ask you to adopt the more conservative value of 1.5 mm of H O, or at 340 GHz, in your integration time calculations (see Fig. C.1 of the 30-m telescope manual). The values in the four last columns/lines of Table 4.3 of the 30-m telescope manual) should then be replaced by:

Freq(GHz) pwv[mm]

340 1.5 0.4 720 0.059

for 10 min integration at an elevation of in a 1 MHz bandwidth.