Proposed Schedule for the Week

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DAY 1:  Monday 9 July

  INTRODUCTION to Millimeter Wavelength Interferometry

9-10 am Introduction. (Melvyn)
. Course outline
--  Day 1  : Basics to get you going.
--  Day 2-4:
  Radio antennas, arrays, aperture synthesis, receivers and correlators.
  Observing techniques, scheduling, calibration, data inspection, imaging
--  Day 5:  Data analysis, future developments, VLBI.

. Source characteristics, instrumentation, and observing techniques
  together define a matched filter to  possible observations with
  millimeter wavelength interferometers.

.  Astronomy from comets to cosmology
-- emission mechanisms: thermal and non-thermal
-- source selection: astronomy, frequency, size, brightness sensitivity

. Atmospheric windows at optical, IR, and radio frequencies

. CARMA site characteristics

10-11 am  APERTURE SYNTHESIS BASICS (Melvyn)

. Radio antennas: collecting area and resolution
. Aperture arrays
. response of a 2-element interferometer to point source.
. coordinate systems: (u,v,w), u,v tracks for different arrays.
. CARMA array characteristics. antennas, Rx bands, correlator.
. Aperture sysnthesis imaging.
. Mapping extended sources. resolving out extended structures
. Calibration, Imaging and Deconvolution.

11-12 am. Antenna tour (DaveW & Dick)

.  Visit to telescopes. Intro to antenna hardware.
-- antenna structure
--  drive system
--  manual, computer control
--  limits and switches
--  cable wraps

12am - 1pm  Lunch.


1-2 pm  Intro to CARMA computers. (Marc)

. computers. data flow. archiving
- control computer: roadmap of machines, disks, directories and
    subdirectories
. school data reduction and analysis space. login, passwords.
. basic observing procedures, on-line monitors and data inspection
- key programs:

2-3 pm    Basic demos (students)
  -- observe a point source (maser or quasar) and a planet.
  -- plot amplitude and phase vs. uvdistance
  -- constant amplitude for point source, Bessel function (with
     phase flips) for planet
  -- set up correlator in various modes, take spectra of Orion

3-4 pm  OBSERVING PROCEDURES (Melvyn)

. Calibrations:
  -- gain(t,f,p) - gain, bandpass, polarization, pointing.
. calibration intervals.  V' = gain(t,f,p) x V + noise
. Observing scripts
. selecting suitable observations for the target sources.
  -- sensitivity
  -- source size; mosaicing.

. CARMA correlator capabilities; selecting a correlator settup.
. choosing calibrators for gain, bandpass, flux and pointing.

4-5 pm  group discussion selecting student projects. (Douglas)

5-6 pm Intro to preparing CARMA observing scripts (Marc)

6 pm Dinner at the CARMA site.

Student projects observed on CARMA array overnight.
DAY 2: Tues 10 July

9-10 am DATA INSPECTION AND ANALYSIS (Melvyn)

. overview of data reduction procedure
. introduction to MIRIAD data reduction package.
. basic Miriad data format: header, history, uvdata, gains, bandpass
. inspecting uvdata: uvindex, uvlist, uvplt, uvspec
. selecting uvdata: keywords select= and line=
. flagging bad data with uvflag
. antenna based calibration; selfcal and mfcal. gpplt. gains bandpass polcal
. rewriting edited data sets with uvaver, uvcat, uvcal

10-11 IMAGING (Melvyn)

. Review of basic math: brightness distribution is FT of visibility data.
. FFT requires convolving onto a grid; choosing the pixel and image size.
  -- mosaicing
. invert; choice of natural, uniform, robust weighting, effect on the
    synthesized beam
. deconvolution algorithms: clean, maxen, mossdi, mosmem, restor

11-12 am  Laptop tutorial reduction and analysis of student data (Melvyn)

12 - 1 pm Lunch at the CARMA site

1-2 pm. CARMA hardware - I.  Receivers and Calibration (Dick)
- introduce system block diagram; receiver, cal load, local osc,
    phaselocks, fiber, downconverter, correlator
- compute energy collected if observing 20 Jy source for 1 yr;
    would need to observe for 10^5 yrs to heat 1 drop of water by 1 C
- receiver types:
    - bolometers: not suitable for interferometry because they
        don't preserve phase
    - HEMT amplifiers: not yet competitive at 1mm
    - heterodyne rcvr: downconvert to lower freq in a nonlinear device
- SIS mixers: photon-assisted tunneling; not a Josephson effect
- cryogenics; closed-cycle refrigerators, compressors
- local oscillator: Gunn oscillator
    - must be synchronized between all antennas; discuss in lecture 2
    - both USB and LSB are downconverted to IF; can be separated
        with 90 degree phase switch; also defer to lecture 2
- combining LO and signal: mylar beamsplitter
- receiver and system temperature
- calibration:
    - ideally, calibrate on loads outside the earth's atmosphere
    - the chopper wheel method
- CARMA sensitivity calculator

2-3 pm. Demos on CARMA system

3-4 pm Planning observations and preparing observing scripts

4-5 pm Source selection and script preparation for student projects

5-6 pm students prepare observing scripts, analyze data.

Dinner at the CARMA site.

Student projects observed on CARMA array overnight.

DAY 3: Wed 11 July

9-10 am CALIBRATION (Melvyn)

. Calibrations - gain, bandpass, polarization, pointing.
. Antenna based calibrations: amplitude and phase closure
. Atmospheric and instrumental phase characteristics
. Tsys and Jy/K
. Pointing
. correlator calibration techniques.

10-12 am calibration and analysis of student projects (all)

12 - 1 pm Lunch at the CARMA site

1-2 pm  special topics in mapping (Melvyn)
- the missing short spacing problem; importance for getting correct
    answers for spectral index, etc; negative sidelobes due
    to extended structure; filling in missing spacings with
    larger single dish or Ekers-Rots scheme
- mosaicing: setting up grid files, linear and nonlinear
    mosaicing schemes
- heterogeneous  array imaging

2-3 pm CARMA software system (Marc)
  -- monitor system
  -- computers
  -- data flow
  -- archiving

2-4 pm Laptop tutorial data reduction and analysis of student data

4-6 pm students prepare observing scripts, and analyze data.

Dinner at the CARMA site.

Student projects observed on CARMA array overnight.


DAY 4: Thurs 12 July

9-10 am CARMA hardware lecture 2 - local oscillators, phaselocks (Dick)
- review system block diagram, heterodyne system, local oscillator
- independent oscillators, 100 GHz, synchronized to fraction of
     one cycle over periods of hours (sounds hard)
- basic phaselock: mix with reference, low pass filter, generate
     correction voltage; keeps phase relationship fixed
- CARMA phaselock chain; synth, YIG, Gunn, 10 MHz, 50 MHz
- numerical example: synth = xxx, YIG = yyy, LO = zzz
- fiber system; linelength correction
- lobe rotation
    - compute differential doppler shift due to earth's rotation 
      for 100 GHz signal incident on 2 antennas 10-m apart: 0.24 Hz
    - lobe rotators
- interferometer response for a double sideband conversion system
- need to offset freq of 1st LO as well as insert delays;
    can be understood as removing differential doppler shift
    due to earth's rotation
- phaselocks; the LO system
- cable length measurement system
- phase switching; Walsh functions
- sideband separation by phase switching; note that only signals
    common to an antenna pair can be separated; noise appears
    in both sidebands
- fiber optic hardware

10-11 am calibration (Dick)
- converting to flux density; aperture efficiency; source
    flux table
 
 12 - 1 pm Lunch at the CARMA site
DAY 5: Fri 13 July

9-10 am CARMA hardware lecture 3 - correlator; software control (James)
- review system block diagram
- correlator is detector and spectrometer for the array
- XF vs FX
- delays, 2nd LO lobe rotation, sideband separation
- correlator modes
- FPGA's
- noise source
- basic architecture of computer control system, CAN nodes

observer's everyday responsibilities (Douglas)
- creating and running the master observing script
- data quality reports
- data archiving and disk management

polarization measurements (Melvyn)
- interferometer response LR, RL, etc in terms of Stokes parameters
- Walsh function polarization switching schemes
- instrumental leakage terms and how to solve for them
- mapping procedures

troubleshooting (Dick, Marc)
- generator, air conditioning
- the anticollision system
- cryogenics
- rcvr tuning
- computer hangups
- clocks; resetting the time
- rebooting procedure:


moving the antennas and calibrating a new array configuration (DaveW, Marc)
- changing IFLO connections in the pits
- running tilt, shimming the antennas
- entering new station coordinates
- finding pointing offsets.
- finding the delay centers
- TV and radio pointing
- finding a baseline
- entering new pointing offsets or baselines

 12 - 1 pm Lunch at the CARMA site

- atmospheric phase fluctuations and what we plan to do about them
- like floppy backup structure on a big telescope; causes
    decorrelation, ruins aperture efficiency
- show results at long and short baselines
- phase structure function
- calibrating by rapid switching; put calibrator in grid file;
    observe weak nearby calibrator often, strong faraway
    calibrator less often
- calibrating by observing the total power; need for extreme
    gain stability; typical results


CARMA future plans (Douglas)
- A-configuration
- Carlstrom's 1 cm system
- wideband receivers
- 23-antenna CARMA array


. analysis of student data


Dinner at the CARMA site.

Student projects observed on CARMA array overnight.
DAY 6: Sat 14 July

hike and go home.

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