Filament Standby - Reduce gun voltage only

[John Donovan]

Question for JEOL FEG (and LaB6) instrument users: Currently, we do not allow the filament standby feature for LaB6 or FEG instruments (that is the ThermalFieldEmissionPresent keyword in the probewin.ini file is set to a non-zero value). These flags are shown here:

FilamentStandbyPresent=1   ; non-zero = enable filament standby feature
FilamentStandbyType=0      ; 0 = reduce heat only, 1 = reduce heat and keV, 2 = reduce keV only, 3 = eternal script
FilamentStandbyExternalScript=""    ; full path to user supplied executable for filament standby procedures

Although it is clear that PFE should never change the filament current on FEG (and also LaB6) instruments, I am curious if any FEG (or LaB6) instrument users would want to have *only* the high voltage reduced (and subsequently restored) for filament standby?

Right now, one can set the FilamentStandbyType=2, and the software will set the high voltage to 1 keV for filament standby ON and then restore it to the previous value high voltage value for filament standby OFF.  But at the moment these flags are ignored for FEG (and LaB6) instruments. 

Do any 8500/8530 instrument users want to be able to set the HV to 1 keV for filament standby mode?

What do you all think?
john

PS on the Cameca FEG SXFive, we set the gun x high (shift) to maximum deflection for filament standby, but the SXFive is a completely different beast...

[John Donovan]

Overall, a JEOL FEG standby feature is not a feature I'm desperate for (unlike, say, a working PI halt command...), but the fact it keeps coming up tells me I'm probably wrong there. And again, if Colin McCrae or Ben or another of the JEOL FEG users says differently, listen to them.

Hi Owen,
Ok, no worries then. Just wondering. 

I accept the dig about the 8200/8500 PI halt command... it's working for the 8900/8230/8530, but Brian is still trying to get it implemented for the 8200/8500 and I apologize about the delay on this, but Brian has a lot on his plate.

Yes, closing the gun valve is probably the best option and I do have the get/set info for the 8530 gun value, which I could add to the "filament standby" code but only for the 8530. Can you tell me if the 8500 gun valve is computer controlled or not?  If it is, we could figure out what the command is for the 8500.
john

[John Donovan]

In terms of giving the most satisfaction to the most customers with the least amount of kludge-ing, I think closing V1 on the 8530 is your best option for a standby mode for that instrument, especially if you already have the API for that.

No software/computer control for the 8500 gun valve, sorry. Maybe ping some of the other 8500 folks (all, what, five of us?) directly and see if they A) have need for such a feature and B) have a suggestion on how to do it? The set-to-low-current thing would probably be easy, but maybe they can suggest something better?

Hi Owen,
I agree.

OK. So I've implemented a close/open gun valve for the flilament standby on/off menus in PFE and asked Ben Buse to test it.  As soon as he confirms it works as expected, I will do a general release.

Of course, once tested, we (that is, 8530 instrument users!) will be able to utilize this gun value function when the automated acquisition is completed if the "Use Filament Standby Afterwards" checkbox was checked...
john