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The value of the reading of ‘Ion 1’ should stay between 0.1 (preferably higher than 1 if possible) and 5 during your entire scan range. To check this move in energy from the start to end of your scan (if running in transmission, the same is required of ‘Ion 2’).
If this is not the case, the gain can be amended using the two buttons under the ‘Sensitivity’ panel. This consists of a numerical factor between 1 and 500 alongside its units (µA/V, nA/V, etc.).
Adjust these freely to get the best settings to cover your energy range to stay within 0.1 – 5 range as best as possible. If this is not possible, consult the beam line scientist.
A typical value of the sensitivity is anything between 500nA/V to 2µA/V but this will largely depend on your experimental set-up and sample.
In some cases you may also need to adjust the ‘Input Offset Current’ settings to access certain sensitivity values:
This is done by closing the ‘Experimental Shutter (SHTR2).
Increasing or decreasing the offset value until the ‘Ion 1’/’Ion 2’ reading lies in the range 0.001 to 0.006. For example, the offset value of 2 to 5 nA should be sufficient with the sensitivity of 500 nA/V.
Feedback: OLD. New instructions in near future
In some cases despite the beam being on and all shutters open, it may be possible the feedback has been lost. The feedback ensures that during changes of the Bragg angle of the crystals in the monochromator (changes in energy), the beam remains stable and in the same position. In cases where a large change in energy is required and so a large change in the Bragg angle, this feedback can become lost.
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