Recent activities on Front End D&D in Japan

Yutaro Sekimoto and Takashi Noguchi, 5-Jul-01

1. NAOJ prepared budgetary proposal of ALMA-Japan for the ministry of
education,
which is based on the new task division approved by EACC in June.

2. Dr. Akitoshi Ueda of NAOJ compared the 100 GHz SIS receiver performance
between waveguide photonic LO and conventional Gunn oscillator.
No difference was found at a level of noise temperature around 30 K.
Next step is quasi-optical submillimeter power measurements up to 1 THz
using log-periodic antenna patterned on the NTT photodiode.

3. We are constructing ALMA-type receiver for ASTE 10 m telescope,
which accomodates three cartridges.
We made fitting test of the receiver before disassemble of the ASTE 10 m
telescope in May.
Today, we removed instruments from the receiver cabin of ASTE.
The ASTE 10 m telescope will be disassembled in this month
and re-assembled in Chile in March 2002.

4. We are studying a single mirror design for band 8 optics.
We are also designing a band 8 cartridge for ASTE.

5. We have calculated thermal design of ALMA receiver
and confirmed that the cooling capacity (0.75W at 3.80 K on 3rd stage, 10 W
at 12.3 K on 2nd stage, and 40 W at 93 K on 1st stage) of the SUMITOMO 3
stage GM cryocooler is enough.
This calculation is based on our modified thermal link,
which is different from RAL's original thermal link.
We will demonstrate NAOJ's thermal link with our cartridges in next three
months.

6. Prof. Hideo Ogawa of Osaka Prefecture University is designing Band 3
cartridge for ASTE.