docs: def ev_to_image_number(offset_us, source_to_detector_m, time_resolution_us, t_start_us, array):
      # delay values is normal 2.99 us with NONE actual MCP delay settings
      """convert energy (eV) to image numbers (#)
  
      Parameters:
      ===========
      numpy array of energy in eV
      offset_us: float. Delay of detector in us
      source_to_detector_m: float. Distance source to detector in m
  
      Returns:
      ========
      image numbers: array of image number
      """
      time_tot_us = np.sqrt(81.787 / (array * 1000)) * source_to_detector_m * 100 / 0.3956
      time_record_us = (time_tot_us + offset_us)
      image_number = (time_record_us - t_start_us) / time_resolution_us
      return image_number