Actually better off not setting the beam to zero before imaging. I assume most users will focus before acquiring an image anyway. Telling the beam to go to zero spot size calls up the values stored in the JEOL software which may de-focus the beam if not correct. Subsequent digitized spot and line analysis will also be with a potentially de-focused beam.
Hi Bill,
Thanks for the explanation.
The original reason we have been sending a beam size zero command prior to image acquisition is that the "default" beam size might be 5 or 10 microns. If we don't send the zero beam size prior to imaging the resulting image will be out of focus.
We then thought about maybe sending a zero size beam after each sample acquisition, and then the beam will already be focused prior to the image acquisition. But if someone manually removes the faraday cup, the beam will be fully focused and then might cause sample damage. Though it is true that if someone is manually or automatically acquiring data, the program will set the proper beam size before unblanking the beam and sample acquisition.
What do you all think about this? We would like to hear some feedback before making such a change to the default operation of the software.
A possible solution to this would be to define the zero beam within the PFE software. At least for the 8900. I suggest a routine in the Analytical Conditions window where once the beam is focused you could press a button to store OL zero beam size coarse and fine values. Alternative beam sizes would use this value as a reference.
So you're suggesting that PFE store these objective lens values internally and use them when resetting the beam size to zero?
By the way it is an interesting thing, but on the JEOL 8900, one can read both the objective lens coarse and fine values, but on the JEOL 8200/8500 one can *only* read the objective coarse value through the communication interface.
Hope you don't mind but here I quoted, from your email to me, your explanation of getting the JEOL instrument to "remember" the current beam size zero focus settings from the UNIX box:
But in the process I discovered the OL fine/ Zero beam value somehow is tied to opening the EOS monitor and then the Probe diameter window. Once a non-zero size is selected in the PD window, it appears the OL fine/Zero beam value is reset to the current value. This makes sense I suppose but if PfE is instructing the JEOL to go to Zero beam size, one needs to be aware of this.
For instance, if you change the Ol coarse and refocus using the OL fine, without going back in to the JEOL software and resetting it, Zero beam size will not be zero. Or for that matter if you were not exactly focused when the OL fine were stored, you could have issues with spot size and image focus using PfE.
I don't quite understand the process you're describing here, but I guess my question is, why can't 8900 users simply be aware that they need to get the instrument to remember what the OL values are before they start trying to acquire images in PFE? Would this be so onerous? Is this what JEOL 8200/8500 users also have to do to get the instrument to remember the beam size zero focus?
The other possibility as described above, is to always have the PFE software reset the current beam size to zero whenever it finishes a sample acquisition. Then the user would be seeing a focused beam any time they manually unblanked the beam. Then they can focus manually easily. But again, I'd like to hear from users of all instruments before we commit to this.
Or maybe we could just add a new flag in the probewin.ini file for this behavior of forcing the beam back to zero after each sample acquisition? I'd like to hear from users of all instruments before we make any such change.
We depend on your feedback and ideas!