Wide-Band spectrometer for HIFI-FIRST

摘要

The wideband acousto-optical spectrometer (WBS) for HIFI-FIRST is comprised of two-array-AOS with 4 times 1 GHz bands each. There are some advantages tothis design, the most important one is that relative frequency and amplitude variations between the 4 bands are rather unlikely. This is demonstrated by laboratory tests, which verify also that fairly slow beam-switching at 0.5 Hz may be a sufficient chop speed for HIFI. The performance of array-AOS has also been demonstrated during measurements at ground-based observatories. WBS consists of three independent units, one IF-, one optics-, and one electronics-unit. Some of the details of the WBS design are described,a nd the present performance estimates are given.