[asac][almanews] ALMA Memo 481 Released

[Stacy Oliver]

ALMA MEMO #481 

Preliminary Tests of Waveguide Type Sideband-Separating SIS Mixer for
Astronomical Observation 

Shin'ichiro Asayama (Osaka Prefecture University/Nobeyama Radio
Observatory), Kimihiro Kimura (Osaka Prefecture University), Hiroyuki
Iwashita(Nobeyama Radio Observatory), Naohisa Sato (National
Astronomical Observatory of Japan), Toshikazu Takahashi (Nobeyama Radio
Observatory), Masao Saito (National Astronomical Observatory of Japan),
Bungo Ikenoue (National Astronomical Observatory of Japan), Hideharu
Ishizaki (National Astronomical Observatory of Japan), Nobuharu Ukita
(National Astronomical Observatory of Japan) 

2003/11/24

Keywords: Sideband-Separating mixer, SIS mixer, ¹²CO(J = 1 - 0)spectrum 

We have developed an integrated sideband-separating SIS mixer at 100 GHz
based on waveguide split block with 4.0-8.0GHz IF. The measured receiver
noise temperatures with 4.0-8.0GHz IF are less than 60K in the LO
frequency range of 90-110GHz, and minimum value of around 45K is
achieved at 100GHz. The image rejection ratios are more than 10dB in the
LO frequency range of 90-110GHz in the laboratory measurements. We have
installed the sideband-separating SIS mixer into the cartridge-type
receiver cryostat for Japanese prototype antenna and successfully
observed a spectrum of ¹²CO(J = 1 - 0) from Orion KL and confirmed the
image rejection ratio as large as 13 dB in the astronomical
measurements. This result is the first astronomical observation with a
waveguide type Sideband-Separating SIS mixer. 

View a pdf version of ALMA Memo #481. 
http://www.alma.nrao.edu/memos/html-memos/alma481/memo481.pdf

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