Performance

From emsuite wiki

Machines must be clean to operate at optimal performance.

Problems occurwhen dirt builds up enough to build up charge.

This leads to dirt charging and discharging.

If resins are used and not cured completely, then contamination can discharge throughout system.

Running at a lower kv on TEMS damages samples more then higher levels.  SEM's are the opposite where higher kv leads to more discharge.

Scanning microscopes are generally mroe dirty then TEMs.  Used every day, they should be cleaned once a year.

Emission meter will indicate dirty column components.  If there is dirt on column and column wall, arc can occur, evidenced by ozone smell when column opened.  Once an arc occurs, it will lead to addditional arc along same path because of dirt being adhered to column wall and filament.

Use metal polish diluted 1:10, strips of tissue, one wipe with tissue.

When filament breaks, don't take cathode apart.


Ammonia is tungsten solvent, which is major contaminant from tungsten filament.

Components of column, if copper based, will start to etch in pure ammonia after 4-5 minutes, so use diluted ammonia 1:10.

Stainless steel can be cleaned in pure ammonia.  Stainless steel cannot be cleaned with amonnia.

Clean cathode every time you change filament.

Clean anode every other time with metal . 


SEM- when you cannot correct astigmatism, it's a good indicator that other things need cleaning.

1- variable aperature.  If changing aperature corrects problem, then it's an indicator that is the problem.

Take aperature out to clean, but cleaning aperature support may be the problem.

Use the EM manual guidelines for good procedures.

Turn instrument off after letting air into system.