pb - When you talk about secondary electrons as if no one else here has given it any thought, I find it hard to believe that you're not some level of troll.
Why don't you introduce yourself the same as everyone else has. Then maybe I can take you seriously.
Faraday Cup
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George Schmermund
- Posts: 262
- Joined: Tue Aug 15, 2006 8:51 pm
- Real name: George Schmermund
- Location: Carlsbad, CA
Re: Faraday Cup
Anything obvious in high vacuum is probably wrong.
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Rich Feldman
- Posts: 1471
- Joined: Mon Dec 21, 2009 6:59 pm
- Real name: Rich Feldman
- Location: Santa Clara County, CA, USA
Re: Faraday Cup
Hey Preston, did you know you have two different user names here?
"prestonbarrows" joined Sat Jun 23, 2012 10:27 pm.
"preston barrows" joined Sat Mar 02, 2013 9:24 pm.
From both I see a number of helpful, knowledgeable posts about vacuum and high voltage technology.
But nothing in the "please introduce yourself" board.
-Rich
"prestonbarrows" joined Sat Jun 23, 2012 10:27 pm.
"preston barrows" joined Sat Mar 02, 2013 9:24 pm.
From both I see a number of helpful, knowledgeable posts about vacuum and high voltage technology.
But nothing in the "please introduce yourself" board.
-Rich
All models are wrong; some models are useful. -- George Box
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prestonbarrows
- Posts: 211
- Joined: Sun Jun 24, 2012 1:27 am
- Real name:
Re: Faraday Cup
viewtopic.php?f=8&t=9598
Cheers guys, didn't realize I hadn't already done that.
George, I have never intended any offence here. Feel free to check my numbers, there is always a good chance they are wrong.
I would be happy to discuss any other constructive theories about the apparent difference between the measurement and theory. So far, you have not offered anything besides unprovoked malice.
Cheers guys, didn't realize I hadn't already done that.
George, I have never intended any offence here. Feel free to check my numbers, there is always a good chance they are wrong.
I would be happy to discuss any other constructive theories about the apparent difference between the measurement and theory. So far, you have not offered anything besides unprovoked malice.
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John Futter
- Posts: 1850
- Joined: Wed Apr 21, 2004 10:29 pm
- Real name: John Futter
- Contact:
Re: Faraday Cup
Preston
whoa up
Us old farts have been around the block a lap or two.
I know you mean no harm and neither does George
But telling us how to suck eggs sticks in the craw a bit----the outcome of this is how we feel on the day
and may include Dismay Dislike Derision Indifference.
I have plotted faraday cup current against electron suppression voltage many times and for the voltages that people use here ie 10 -70kV you will need to
bias this electrode up to around 400 volts negative to suppress all the secondaries
As I have listed here on the site you can do this without a seperate bias supply by using a tansil diode PKE400A or similar. I measured the reverse characteristics of a hundred of these to make sure that they posed no burden before breakover. Its somewhere here on the site.
One final note
This is Georges post on how he is doing it!!!!!
this includes me and you Preston on not diluting it
whoa up
Us old farts have been around the block a lap or two.
I know you mean no harm and neither does George
But telling us how to suck eggs sticks in the craw a bit----the outcome of this is how we feel on the day
and may include Dismay Dislike Derision Indifference.
I have plotted faraday cup current against electron suppression voltage many times and for the voltages that people use here ie 10 -70kV you will need to
bias this electrode up to around 400 volts negative to suppress all the secondaries
As I have listed here on the site you can do this without a seperate bias supply by using a tansil diode PKE400A or similar. I measured the reverse characteristics of a hundred of these to make sure that they posed no burden before breakover. Its somewhere here on the site.
One final note
This is Georges post on how he is doing it!!!!!
this includes me and you Preston on not diluting it