TCCON > Sites > Eureka > Instrument History > Site Visit 2017-02-24 to 2017-03-19

Site Visit 2017-02-24 to 2017-03-19

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Mar. 13, 2017

Erik Lutsch, Pierre Fogal and Sébastien Roche aligned the instrument. See the word document Eureka_alignment_170313 for some figures and photos.

Photos of fringe patterns are given with distance from ZPD. The ZPD position was estimated before the alignment by noting the mirror position when the fringe pattern would "flip".

 

Alignment of the laser to the interferometer axis, with the CaF2 beamsplitter installed:

  Zero (V) Max (V) Min (V)  Pk-Pk (V) ME
    ZPD ZPD+45 cm ZPD+257 cm ZPD ZPD+45 cm ZPD+257 cm ZPD ZPD+45 cm ZPD+257 cm ZPD ZPD+45 cm ZPD+257 cm
Before                           
LASA -9.8 -2.4 -2.4 -4 -9.2 -9.2 -8.4 6.8 6.8 4.4 0.85 0.85 0.61
LASB -9.8 -3.2 -3.6 -4.6 -9.4 -9.2 -8.6 6.2 5.6 4 0.89 0.82 0.63
After                          
LASA -9.6 -2.2 -2.4 -2.7 -9.3 -9 -8.9 7.1 6.6 6.1 0.9 0.85 0.82
LASB -9.6 -3.2 -3.72 -3.8 -9.5 -9.36 -9.2 6.3 5.6 5.4 1 0.92 0.87
 

 

Mar. 04, 2017

  • On Feb. 25 and 27 we measured AC signals for the amplitudes, and the scanner was in "Front short adjust mode" for ZPD measurements and in "Back short adjust mode" for MOPD measuurements. Here we measure the DC voltages of the laser signals with the scanner in stop mode at ZPD and MOPD.
  •  DC voltages for LASA and LASB. The modulation efficiency is obtained with:

 

 

CaF2 LASA (V) Pk-Pk (V) Vzero (V) ME LASB (V) Pk-Pk (V) Vzero (V) ME
ZPD

-2.4

-9

6.6 -9.6 0.85

-3.6

-9

5.4 -9.6 0.82
MOPD

-4.4

-8.4

4 -9.6 0.63

-4.8

-8.4

3.6 -9.6 0.6
KBr LASA (V) Pk-Pk (V) Vzero (V) ME LASB (V) Pk-Pk (V) Vzero (V) ME
ZPD

+3

-8

11 -9.4 0.80

-1.2

-8.2

7 -9.4 0.75
MOPD

+0.6

-6.6

7.2 -9.4 0.56

-2.4

-7.2

4.8 -9.4 0.52

 

Feb. 27, 2017

  • Repeat LASA and LASB measurement:

 

CaF2 LASA (V) Pk-Pk (V) LASB (V) Pk-PK (V)
ZPD

2.9

-3.6

6.5

2.4

-3.1

5.5
MOPD

1.2

-1.4

2.6

1.2

-1.4

2.6
KBr LASA (V) Pk-Pk (V) LASB (V) Pk-Pk (V)
ZPD

5.3

-5.6

10.9

3.2

-3.6

6.8
MOPD

2.4

-2.6

5

1.8

-2

3.8
 

 

 

 

Feb. 25, 2017

  • The LASA and LASB amplitudes (peak to peak) were measured with an oscilloscope at the front (Front short adjust mode) and back (Back short adjust mode) positions, with both beamsplitters.  
  KBr CaF2
LASAfront (V) 10.5 6.4
LASA back (V) 7.2 3.8
LASB front (V) 7.1 5.8
LASB back (V) 4.4 3.6

  

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Files 3

FileSizeDateAttached by 
 Eureka_alignment.pdf
No description
4.06 MB07:15, 4 Oct 2017sebastien.rocheActions
 Eureka_alignment_170313.docx
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1365.57 kB10:21, 15 Sep 2017sebastien.rocheActions
 FTS_align.jpg
Photo of the bruker 125HR with annotations for the alignment steps
4.97 MB10:41, 15 Sep 2017sebastien.rocheActions