Mmwave diagnostics on the 170 GHz test facility

1
Mm-wave diagnostics on the 170 GHz test facility
Checking polarization using Rotating probe. Can
be done directly in the beam or using a foil
Beam profiling using IR camera
Water load
Vacuum vessel for steerable mirror
Window
MOU
Mmw-beams
Transmission line
Hinge for movable vacuum vessel
Looking through using IR camera (detection of
hotspots)
2
High power 110 GHz polarization measurementsby
means of a rotating probe at TEXTOR
Dogleg
110
1140
MOU
Switchmirror dump
MTP and
Polarizer
845
4555
MP2
0.4 MW, duty cycle 1100 10 ms/shot, synchronized
to gyrotron trigger.
3
Rotating probe shielding and location
4
Curve fitting of the rotation scan of the probe
to obtain ellipticity and ellipse
The detector signal of the probe is sampled with
5 ms averaging (during the shot) by an ADC and
converted with a calibration table to power.
Actual high power measurement!
Horizontal polarization measurement, probe starts
and finishes with vertical polarization
5
Ellipticity result of polarization measurements
Theoretical
Measured at high power
6
Angle of ellipse result of polarization
measurements
Theoretical
Measured at high power
7
IR Camera window material

• IR camera specs
• AVIO MK2000 MkII (gas cooled)
• Detection wavelength 3..5.4 ?m
• FOV horizontal 15
• vertical 10
• IR camera (250x200x100 mm3)could be used to see
  the beam profile using a foil or looking at a
  window.
• Can be used to determine power
• Fused silica window, not suitable for use as
  transparent medium with this IR camera

Pulse length 10 ms 1.5 MW 1100 duty cycle