Download John`s AMS Instrument Developoment

High Emission Current Operation
• IPP vs. emission current plot, with AB and
IE, tungsten signal also increases. W,
IPP, AB, and IE all increase with emission
current. Lifetime is very short with higher
current. Looking into 2% thoriated
tungsten filaments, but no apparent
reduction in tungsten signal with the
thoriated (alloy vs. surface coating?).
Final: haven’t gotten there yet.
Summary of Ionizer Enhancements
• Closed ionizer, IPP = 400 (signal increase)
• Small volume ionizer, IPP =800 (S/N
increase)
• Magnets, IPP =2000 (but impact on size
resolution)
• High emission current ionizer, IPP =8000+
(dynamic range limited)
– Need to evaluation S/N increase
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