[Sneap] problem of ion source

[Kim Gunther]

CS Lee,
 
As a substitute for the mesh cathodes, we have provided directly heated
Barium Dispenser Cathodes for this application.  Chris Westerfeldt has
had some experience with this and may want to comment.  Our product is a
machined porous Tungsten coil with BaO, Al2O3 and CaO impregnated into
the pores.  A typical design is shown below.  Let me know if you would
like to explore this. 
 
 
Best regards,
 
Kim Gunther
HeatWave Labs
gunther at cathode.com <blocked::mailto:gunther at cathode.com> 
831-722-9081
fx 831-722-5491

________________________________

From: sneap-bounces at tunl.duke.edu [mailto:sneap-bounces at tunl.duke.edu]
On Behalf Of cslee
Sent: Monday, December 10, 2007 8:41 PM
To: sneap at tunl.duke.edu
Subject: [Sneap] problem of ion source


Dear Friends:
 
18 years ago I started to use 358A ion source ( duplasmatron produced by
general ionx, now the same type of ion souce is produced by high voltage
engineering in europe neitherlanders).  Three four years ago  I had the
exactly same experience as the manual statement, unfortunately recent
three four years I have to try and "guess" a lot to make the ion source
work.  It does waste too much time.   The coating solution I used,
except Cathode Coating T-33C-118 (Ba-Sr-Ca) CO3 56-31-13%., we aslo used
the product from HV company (it only marked: A848001, B-6976 with a HV
trade mark).    According to the manual when we bake the filament with
the coating, the voltage between the anode and intermediate anode (or
electrode) is over 34 volts.  Then there is enough thermal electrons to
induce a stable discharge.  Now the voltage we measured only less than 1
or 2 volts, and the the current we used is over 26 amperes.   This
coating solution we just purchased last year, so there are some problems
which we don't find it out yet.   If you know where is the problem,
please  informe me I'll appreciate that very much.  Otherwise you can
provide me which university or comapny use the same types of coating and
ion source, I may  seek their help.
 
Here I delievered to you the description about the coating procedure
from the manual of the ion source .
 
" wash" the filament back and forth in the coating to insure it flows
through the gauze mesh.  Approximately 20 seconds is sufficient.
(quote from the accompanied files).
 
 But now we need to work about two hours to coat the solution on the
mesh." and it doesn't work at all.
 
 
Best regards
 
 
CS Lee 
 
email address: cslee at phy.ncu.edu.tw
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