[asac][almanews] ALMA Memos 453 and 455 Released

[Stacy Oliver]

ALMA MEMO #453

An Integrated Sideband-Separating SIS mixer Based on Waveguide Split Block for 100GHz Band

Shin'ichiro Asayama (Osaka Prefecture University/Nobeyama Radio Observatory),
Hideo Ogawa (Osaka Prefecture University),
Takashi Noguchi (Nobeyama Radio Observatory),
Kazuji Suzuki (Instrument Development Center of School of Science, Nagoya University),
Hiroya Andoh(Toyota National College of Technology),
Akira Mizuno(Solar-Terrestrial Environment Laboratory, Nagoya University)

April 2003

We have been developing an integrated sideband-separating SIS mixer at 100\ GHz based on waveguide split block. 
The measured single-sideband (SSB) receiver noise temperatures with L-band IF ($f_c$ = 1.5\ GHz ) are less than
60\ K in the LO frequency range of 90--115\ GHz, and minimum >value of around 35\ K is achieved at 100\ GHz. 
The image rejection ratios are more than 11\ dB in the frequency range of 90--110\ GHz. We have installed the
sideband-separating SIS mixer into an atmospheric ozone measuring system at Osaka Prefecture University and 
successfully observed an ozone spectrum at 110\ GHz in SSB mode. This experimental result indicates that the 
sideband-separating SIS mixer is very useful for astronomical observation as well as atmospheric observation.

View a pdf version of ALMA Memo #453.
http://www.alma.nrao.edu/memos/html-memos/alma453/memo453.pdf

-------------------------------------------------------------------------------------------------
ALMA MEMO #455

Cartridge Test Cryostats for ALMA Front End

Y. Sekimoto, T. Kamba, S. Yokogawa, M. Sugimoto,
T. Okuda, R. Kandori, K. Tatematsu, K. Muraoka,
A. Ueda, T. Nishino, N. Okada, T. Fukuda,
K. Kaneko, H. Ogawa, K. Kimura,
K. Noda, K. Narasaki, and K. Suzuki

April 2003

We have developed four cartridge test cryostats for ALMA FE cartridge-type receiver with taking account of 
reliability and easy operation. It uses a simple, compact and efficient thermal link between a cartridge-type
receiver and a plate connected to a 3 stage Gifford-Mcmahon (GM) cryocooler. The cooling time of the 
cartridge-type receiver is less than 10 hours. With a cartridge loader, a cartridge-type receiver is easily
inserted and extracted in a condition that the cryostat is closed.

View a pdf version of ALMA Memo #455.
http://www.alma.nrao.edu/memos/html-memos/alma455/memo455.pdf
_______________________________________________
Almanews mailing list
Almanews at listmgr.cv.nrao.edu
http://listmgr.cv.nrao.edu/mailman/listinfo/almanews