Calibrating Monochromator

Every time a component of the monochromator (MC) is adjusted (light source, input slit, output position, etc), the feed from the MC requires calibration anew. 

Calibrating MC requires three steps

1. Calibrate spectrograph (not necessary if spectrograph is already calibrated)
2. Take MC data on spectrograph
3. Use gathered data to calibrate spectrograph

We detail an example below.  In this example, we use the StellarNet Inc Black Comet spectrograph, which we calibrate with the Ocean Optics KR-1 calibration light source.  Future re-calibrations of MC should be able to use the same calibration of the StellarNet spectrograph, which we include in the GitHub repository with the calibration scripts:

XXX

Here are the steps in our example:

STEP 0: If running this analysis on a new computer, you must download the StellarNet drivers for the black comet spectrograph. Here is how:

1. Download the SpectraWiz software.  The version for Windows 10, downloaded on 03/17/2022, is available on the above GitHub repository.  Various versions also available at the StellarNet website: https://www.stellarnet.us/stellarnet-downloads/ (Serial num of Black Comet is 18042612).
2. Useful instructions from StellarNet are available here: https://www.stellarnet.us/wp-content/uploads/Spectrometer-Installation.pdf Additional steps/notes are:
   
   1. Step 1: When you execute the file as administrator, the program will say something about PnPutil.exe not being recognized.  That is okay.  Move onto Step 2. 
   2. Step 5: after running the SWUpdatezAP-Install632 script as administrator, you may get an error popup that says something like "run as administrator failed".  This is okay.  See if the StellarNet spectrograph has shown up on the desktop.

STEP 1: Calibrating Spectrograph with KR-1 Light Source

1. You need to determine your wavelength solution (reported wavelength vs true wavelength) of your calibrating spectrograph.  
   
   1. This step does not need to be repeated every time MC requires new calibration, provided the old spectrograph calibration data is available.
2. Pick a very small optical fiber to connect your calibration light and the spectrograph
   1. Very small as the raw KR-1 source is too bright for the spectrograph if not attenuated
3. Take an image of KR1 lamp with spectrograph

STEP 2: Take monochromator data with spectrograph

1. Plug optical fiber from monochromator output into Black Comet spectrograph
   
   1. MC end of fiber SHOULD NOT BE moved 
2. Move monochromator to 700 nm, and set spectrograph exposure time to ~10ms
3. Place an ND filter in spectrograph input path, selected to make Black Comet peak intensity at this exposure time and wavelength ~10-20k
   1. The spectrograph sensitivity with the ThorLabs halogen light peaks around 700nm.  So we make a minimal exposure time give good S/N at that wavelength.
4. Take a data series, starting from ~350 nm and ending at ~1050 nm. 
   1. Use Python to step MC forward
   2. Use Black Comet to save the data. 
   3. This requires manually saving the black comet files, and so cannot be easily automated. 
   4. Here is an example of the run python scripts:
      

      $ cd Documents/PythonScripts/CBP
      $ python
      >>> import monochromator as mono 
      >>> my_mono = mono.CornerStone260('COM3') #Need to check which COM port mono is read at 
      >>> waves = list(range(350, 1051, 52)) 
      >>> for wave in waves: 
          my_mono.GoWave(wave) 
          input('Monochromator  at wavelength ' + str(wave) + ' nm.  Press any key to move to next wavelength (SAVE THE FILE FIRST THOUGH!!!!)') 

      *** Save the file, such as BC_mono_XXXnm_XXXms.SSM.  Then press a button ****
   5. You will need to adjust the exposure time to keep the number of counts in a good range (~5k-40k).

STEP 3: Run the wavelength solution

1. Run the XXX script.