[mmaimcal]Biweekly Calendar of the ALMA Project at NRAO

Sat Jul 24 23:07:33 EDT 2004

                        BIWEEKLY CALENDAR OF THE ALMA PROJECT at NRAO
                                July 19 - August 2, 2004

******************************** THIS BIWEEK ***********************************
As of 28 June, K. Y. Lo has assumed the role of Interim NA ALMA Project Manager, until 
the new Project Manager is in place.  Other personnel changes were detaileded in 
an announcement dated 2004 July 20.
---------------------------------------------------------------------------
The Japan Negotiating Team, a committee of the ALMA Board, and representatives of the
Japanese NINS have reached a draft Agreement concerning the construction of the Enhanced 
ALMA, between ESO and the National Science Foundation, and The National Institutes of Natural 
Science of Japan (NINS). 
---------------------------------------------------------------------------
European Project Management has established a Fiber Optic
Management Group to investigate fiber optic design and specification; the Group is led by the
project office and will work with commercial companies to provide detailed system design.
A Review panel will make recommendations by 2004 July 26.
---------------------------------------------------------------------------
Past issues of this Calendar may be viewed at 
http://www.cv.nrao.edu/~awootten/mmaimcal/ALMACalendars.html
*******************************************************************************

General Happenings

Chile        ALMA Camp at OSF site now complete except for paint and gravel around the camp.
              The ALMA Board will hold its face-to-face meeting at the ALMA Camp 2004 Nov 2-3.

TUC          The critical functions of the laser synthesizer are being tested prior to final 
              wiring and assembly. Construction of the photonic distribution module for the 
              SI test is in progress.  The completed RF Simulator is undergoing detailed tests.
              Both First LO Driver assemblies have been locked to an optical reference and have
              been under reliable computer control.

NAASC        Detailed planning for ALMA Operations and NAASC staffing continues. 

NTC          A revised specification for the correlator, incorporating the Tunable Filter 
              Bank features, has been written and submitted as ALMA-60.00.00.00-001-B-SPE. 
              Excluding the TFB cards, 59% of the assembled printed circuit 
              boards needed for the first quadrant have been received. 300 boards, or 
              53% of the total needed for the first quadrant, have been successfully 
              bench tested and are ready for installation.

AOC          Computing CDR#2 was held in Denver. Written report will be submitted in 
              early August.
	     One set of populated prototype antenna racks delivered to SI for test.
	      The path through the DTS Transmitter and DTS Receivers into the correlator has
              been tested satisfactorily with data generated inside the DTS Transmitter.
	      Delivery of the preliminary Downconverter module set #1 is expected by July 16.

DAILY CALENDAR (Times EDT)
Mon  19 July
All day event: System Engineering Planning Meeting
10:30 AM-12:00 PM: JAO/IPT Teleconference
 Tue 20
10:30 AM-11:00 AM: Science IPT Telecon
 Wed 21
 Thu 22
8:30 AM-10:00 AM: JAO Teleconference
 Fri 23 
 Sat 24
 Sun 25 
 Mon 26
1:00 PM-2:30 PM: NA DH Teleconference
 Tue 27
All day event: Back End Planning
 Wed 28
All day event: Back End Planning
 Thu 29
All day event: Back End Planning
8:30 AM-10:00 AM: JAO Teleconference
 Fri 30
8:00 AM-1:05 PM: Back End Planning
 Sat 31
 Sun 01 August 

****************************** UPCOMING EVENTS ******************************
ALMA Calendar  

    * 5 August -- ALMA Board Telecon
    * 24 September -- ALMA/EU Meeting, Garching
    * 27-28 September -- ASAC face-to-face meeting, Charlottesville
    * 28-30 September (TBC) -- face-to-face IPT Leads Meeting, Charlottesville
    * 11-12 Oct -- AMAC Meeting, Florence, Italy
    * 2-3 Nov -- ALMA Board Face-to-face Meeting, OSF, near San Pedro de Atacama

******************************* TECHNICAL NEWS *******************************
ALMA Memo # 484  A New Configuration for the ALMA Laser Synthesizer
Bill Shillue and Larry D'Addario National Radio Astronomy Observatory

This memo describes the results of a test of a new configuration of laser
synthesizer for ALMA. The ALMA laser synthesizer is the source of the 1st LO
photonic reference, in which a two-wavelength optical beatnote is
transmitted by optical fiber from the ALMA AOS technical building to 
each of the array antennas. It is then used at the antenna as the reference for 
the first local oscillator, after a photomixer converts the beatnote into a
radio frequency in the range 27-142 GHz. This report is a condensed 
version of a more detailed test report available on ALMAEDM.

In this new configuration, a slave DFB fiber laser (DFB-FL) is phase-locked
to a master laser using an external fiber frequency shifter (FFS). The 
use of an FFS as an external tuning element removes the requirement for fast
modulation response from the slave laser that had heretofore been an
obstacle in finding a suitable tunable slave laser. This technique has been
implemented previously for very low phase-noise applications.

The relatively wide modulation bandwidth allows for a wide bandwidth
phase-lock loop. Coupled with the intrinsically low phase noise of the
DFB-FL, the resulting beatnote is shown to have very low phase noise.

View a pdf version of ALMA Memo #484. 
http://www.alma.nrao.edu/memos/html-memos/alma484/memo484.pdf
---------------------------------------------------------------------------
ALMA Memo # 495 Estimated Performance of the Water Vapour Radiometers
Richard Hills (Cavendish Laboratory, Cambridge, UK)

The sensitivity and accuracy to be expected from the ALMA water vapour
radiometers is estimated. Even with quite pessimistic assumptions about
noise temperature and gain stability, it appears that the sensitivity of 
the present design is at least a factor of 2 better than the specifications. 
It is more difficult to predict the medium term stability and accuracy that
will be achieved, but the indications are that these will not be a limiting
factor in using the data from the radiometers. An estimate of the errors
that would occur in correcting the single-dish pointing for the effects 
of water vapour gradients is also given.

View a pdf version of ALMA Memo #495.
http://www.alma.nrao.edu/memos/html-memos/alma495/memo495.pdf
---------------------------------------------------------------------------
ALMA Memo # 502 ALMA Band 6 Prototype Cartridge: Design and Performance
G. A. Ediss, M. Carter (IRAM), J. Cheng, J. E. Effland, W. Grammer,
N. Horner, Jr., A. R. Kerr, D. Koller, E. F. Lauria, G. Morris,
S-K. Pan, G. Reiland and M. Sullivan National Radio Astronomy Observatory

This paper describes the design and performance of the initial Band 6
(211-275 GHz) ALMA cartridges. The incoming beam is coupled by 4-K
reflecting optics to a scalar horn followed by an orthomode transducer. 
Each polarization is down-converted in a sideband-separating SIS mixer 
integrated with a pair of 4-12 GHz IF preamplifiers. Stringent thermal management 
and LO loss requirements are satisfied by using an overmoded stainless-steel
waveguide between the LO triplers on the 100-K stage and the 4-K mixers.
For ease of maintenance, all connections into the vacuum vessel are "blind
mating."

View a pdf version of ALMA Memo #502.=20
http://www.alma.nrao.edu/memos/html-memos/alma502/memo502.pdf
*******************************************************************************
Errata: The last issue referred to an Integration Center at the NTC; the correct
term is Front End Integration Center.  
*******************************************************************************

Please send information for upcoming calendars by Friday evening of the
preceding biweekly period to Janet Bauer or Al Wootten via e-mail 
(jbauer at nrao.edu or awootten at nrao.edu).

The calendar will be issued between late Friday and sometime on Monday by e-mail
to all NRAO scientific staff members and anyone else interested. A specific
mailing list, alma-info, has been created for anyone wishing to receive it.  Past issues
are now available at http://www.cv.nrao.edu/~awootten/mmaimcal/ALMACalendars.html