Status

1
Status

• DETECTORS
• Baseline for 2mm NICA 5a (144 pixels, IRAM, 30nm
  sputtering) average sensitivity
• 6mK/Hz0.5 (1Hz) corresponding roughly to NEP ?
  610-16 W/Hz0.5 (1Hz). Before de-correlation.
• Tested one array made in Trento/Roma for 2mm.
  Found about 12mK/Hz0.5 (1Hz).
• Still working to improve the 2mm IRAM-Néel 2mm
  array (e.g. cross-talk, thickness, HF, film)
• Best pixels tested had 2.7mK/Hz0.5 (1Hz). Before
  de-correlation.
• - Baseline for 1.25mm SRON (IRAM, 30nm
  sputtering) average sensitivity 50mK/Hz0.5
  (1Hz)
• NEP ? 810-15 W/Hz0.5 (1Hz). PRELIMINARY. Imaging
  OK. Resonances OK.
• Tested one LEKID array made in Trento/Roma for
  1.25mm. Found about 30mK/Hz0.5 (1Hz) but
• some problems with resonances (coupling not
  adapted).
• As agreed, the priority is for the SRON array if
  the Roma/Trento one isnt 2.5 times better in
• Sensitivity. Improvements ongoing on both sides.
  Time until first week of October for testing.
• OPTICS
• Full dual-band tested last week.
• Polarizer not flat at 300K but imaging seems OK
  (full system test 25/08/2010)
• Still waiting one last HPE filter with the good
  diameter (should arrive)
• Background seems lower with the new optics (40K
  vs. 70K equivalent).

2
Summary

• WE THINK A SHORT TECHNICAL RUN (5x12h) AT THE
  30-m IS JUSTIFIED BY
• - IMPROVEMENT on 2mm BAND sensitivity (factor
  estimated in 2?4)
• - NEW 1.25mm BAND (simultaneous !)
• - LARGER NUMBER OF PIXELS (gt 3 times more than
  last year)
• IF ACCEPTED WE WOULD NEED
• 8 dewars of helium (were carrying 2 more from
  Grenoble)
• more information on receiver cabin dimensions
• to check again that the Ethernet cable from the
  cabin is OK
• .

3
3-6dB deep ? coupling OK
Problem. 2-3 resonances lost.
NICA 5a
Process IRAM (sputtering), 30nm, HR silicon,
300um thick. Design NICA 5a
4
NICA 5a BEAM
FWHM 28mm S/N on the  planet  3000 Hz0.5

• Assuming ?T20K (200K of 8mm
• diameter planet diluted over 28mm
• beam), means
• 20K/3000 ? 7mK/Hz0.5
• ? consistent with Sky simulator
• estimation

5
OPTICAL CONFIGURATIONS
TELESCOPE FOCAL PLANE
TELESCOPE
LABORATORY
620 mm
6
For 6mK difference T on focal plane we calculate
(assuming 0.35 instrument Transmission and
130-165GHz band) 5.510-16 W difference per pixel
(2.25x2.25mm) DECORRELATION VERY IMPORTANT.
7
132 pixels, 2mm array. Al box (could not be a
good idea) Resonances spacing 2MHz or less
SRON 256 pixels array. Resonances Spacing 4MHz