[mmaimcal] Q-band on ALMA

[Al Wootten]

Steven T. Myers writes:
 > Also, is anyone else even a little concerned about putting all the
 > receivers in a single (4K) dewar?  It might be good to have a second
 > 15 K dewar with 30-45 GHz band and maybe the 86+ GHz band also.  This
 > would ameliorate some of the percieved extra costs associated with
 > the Ka/Q band stuff.
The current plan for 30-45 GHz has that receiver in a second dewar with
the beam diverted via a pickoff into that dewar.  I don't think this is
written down anywhere, but it is John Payne's plan.
 > 
 > By the way, the project book has 67 - 90 GHz and 89 - 116 GHz bands,
 > in which case the 67 - 90 is a likely candidate for HFET/MMIC tech.
 > Is this still in the plan, or like the rest of the project book is
 > this horribly out of date?
This is likely but TBD.  For one thing, this awaits an estimate of whether
the attainable 1/f noise can meet the spec in the project book.
 > 
 > It is likely that several documents in support of the low bands will
 > need to be prepared.  Keep thinking about this...
And don't forget Neil Erickson proposed covering 3mm with just one band,
cutting out everything from 67-75 (near and dear to my own heart)...

Al