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DARHT VLT Meeting Joe Kwan Mar 13, 2007. No more drooping beam pulses after we fixed a poor connection. < 1.9 eV means cathode reaching 10 A/cm 2 with < 1050 º C. Cathode loading curves. Miram Curves. So far the highest current density was space charge limited.
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DARHT VLT Meeting Joe Kwan Mar 13, 2007
No more drooping beam pulsesafter we fixed a poor connection
So far the highest current density was space charge limited We are in the process of adding a negative gate voltage, to allow a dc bias on the Faraday cup housing, in order to increase the gun perveance.
We will need more optics to make the FAR pyrometer work properly
Performance of 311X with poor vacuum Presented by Glen Westenskow March 13, 2007
For operation with J > 2 A/cm2 at 1x10-7 Torr need T >1043 Cb Space Charge limited Hot case at 1x10-7 Torr
For operation with J ~ 3 A/cm2 at 5x10-8 Torr need T ~ 1005 Cb 4 A/cm2 5x10-8 Torr case
Cathode surface degrades overnight at 10-8 Torr After “activation” previous day
After a modification to our pulser we hope to determine the vacuum level needed for operation at the 10 A/cm2 level.