IFTSUV: an Imaging Fourier Transform Spectrometer in the UV

1
IFTSUV an Imaging Fourier Transform Spectrometer
in the UV

• Anne Millard, 3rd year PhD student, directed by
  P. Lemaire and J.-C. Vial

2
Scientific objectives

• Add spectral information to 2D images
• ? Spectra of large structures / structures
  simultaneously on different positions on the
  Solar disk
• Detection of explosive events and fast moving
  phenomenons
• Speed distribution horizontal (imaging) and
  vertical (spectroscopy)
• Resolve small structures

3
Instrument specifications

• Wavelength H-Lyman ? (121.6 nm)
• Spectral resolution ??0.02nm
• Depending on the mission
• Orbit heliosynchronous preferred (high TM rates)
• FOV and spatial resolution
• Telescope 3 cm Field 0?1.1R? ? 33' x 33' , r
  1"  high resolution
• Telescope 30 cm Field 30" x 30", r 0.1" very
  high resolution

4
Working principle

• Intensity due to spectral component dk
• Total intensity in the interference pattern
• Spectral distribution of intensity

k1/? ? OPD
5
Simulations
6
IFTSUV mock-up

• Folded Michelson, compact and symetric.
• ?200nm
• Scanning mirror on a nanopositioning translation
  stage.
• Beam splitted by central diffraction grating.
• Beams recombined at the focus of an off axis
  parabola.

7
IFTSUV mock-up parameters

• Sources
• Visible red laser 633 nm frequency stabilised
  and green laser 543.5 nm
• UV continuum (white light) rays (hollow
  cathode lamp)
• Detection
• Visible CCD (COHU 4710), 699 x 576 pixels (9.2
  ?m x 8.3 ?m)
• UV EMCCD (ANDOR tech DV 887), 512 x 512 pixels
  (16 ?m x 16 ?m), back illuminated, MgF2 window

• Paramètres
• ? 200 nm
• R 4000
• ?? 0.05 nm ? ?? 0.08cm-1
• ?? 25nm
• Mirror step 110nm
• Maximum OPD 800 ?m
• Measurement points 3700

8
IFTSUV mock-up
Possibility to control the positionning in
visible light while working in UV.
9
First result
10
Difficulties

• Measurement of the OPD.
• Maintaining the superpositions of the images at
  the focus on the whole scanning range.
• Air flow and variation of environment parameters.
• Synchronous management of all the electric
  systems involved in the instrument (detection,
  control, command)

11
Next steps

• Search of the position OPD 0 using a
  combinaison of 2 lasers
• Set-up of the UV path ( sources and detector)

12
Thank you