hi ... there is very likely a correlation between quality of the vacuum and filament lifetime.
it had been recommended to us to monitor the vacuum continuously on the rigaku ru300 (?) generators we had at the time. this was fairly easy by just plugging a left over plotter from an old chromatography station into two plugs 'under the hood' of the machine (make sure you set the plotter to an appropriate range). these ports output a voltage proportional to the actual vacuum and allowed us to have a complete 'vacuum history' of the machine for reference at all times. i found this very useful for the initial burning in of filaments or ramping up after shutdown, since you could nicely see when the vacuum was really good enough to ramp up power and voltage, and you would see it spiking, if you went to fast. we, interestingly, also saw a variety of other power spikes in the plots, that we maybe should have followed up on. they might have been interferences from other machinery in the electrical circuit, or very short leaks in the vacuum system. something that might be interesting to know, if it exists. it would also give you a better idea when to start making sure to have replacement magnetic seals available. the vacuum also seemed to get notoriously worse when the filament was about to burn. there is very likely also some way to record the vacuum in a somewhat more sophisticated manner and even put the values on a website (together with data from the cryo), so you can get a better feel for how the generator is doing from home over the weekend. the other good thing about this is, that your provider might be more inclined to replace your filaments, if you can prove that the vacuum has been just fine, all along (and not only when you accidentally happened to look at the front panel). cheers ingo Peng Zhang wrote: > Dear Pat and friends, > > Our lab has a ultraX18 5.4kw x-ray generator, and the lifetime of the > filament is more than 1000 hours before rigaku recalled and changed the > vacuum pump. I noticed that the lifetime is really related with the the > vacuum. Ideally it is below 0.1mpa and the lifetime can be longer than > 1000 hours, but the changed vacuum pump does not work so good than before, > and the lifetime is shortened to up 800 hours. > > Did anyone meet the similar problem and share the experience in the > maintenance? > > Thanks. > > >> Dear Colleagues, >> >> During more than three years of operation, I have recorded considerable >> difference in filament lifetimes on my Micromax007: roughly in the range >> 500-2000hrs. Some of this may be accounted for by poor manufacture and >> Rigaku have, in the past, noticed this problem and replaced some >> filaments. For the last three filaments fitted, two have lasted about >> 500hrs and the third about 2000hrs. These filaments were replacements. My >> generator running protocol has been constant throughout. >> Interestingly, the filaments show no visible sign of wear or damage (even >> the 2000hr one) and are only changed when the generator starts to shut >> down on OL or FC limits. >> I recall earlier Rigaku generators that would give 2000hrs when well >> maintained and they ran at 5.4KW compared to the 800W of the Micromax. >> I would be grateful for any comments or suggestions from other Micromax >> operators. >> >> Sincerely, >> >> Pat Bryant >> >> Dr Pat Bryant >> Senior Experimental Officer >> Macromolecular Crystallography Core Facility >> Faculty of Life Sciences >> Michael Smith Building >> The University of Manchester >> Oxford Road >> Manchester M13 9PT, UK >> Phone: +44-161-275-5090/5658 >> Fax: +44-161-275-1505 >> email: [EMAIL PROTECTED] >> Intranet:http://www.intranet.ls,manchester.ac.uk/facilities/research/xraycrystallography >> Internet:http://www.ls.manchester.ac.uk/research/facilities/xray >> >> >> > > > -- Ingo P. Korndoerfer, PhD Head of Crystallography CrystaX Pharmaceuticals, S.L. Parc CientÃfic de Barcelona Josep Samitier 1-5 08028 Barcelona Tel.: +34 93 403 9093 Fax: +34 93 403 4788 e-mail: [EMAIL PROTECTED]
