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Count 1ns pulse
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Paul Taylor
electronics forum beginner


Joined: 10 Feb 2005
Posts: 45

PostPosted: Fri Jul 21, 2006 8:41 am    Post subject: Re: Count 1ns pulse Reply with quote

<cs_posting@hotmail.com> wrote in message
news:1153424608.754771.307490@s13g2000cwa.googlegroups.com...
Quote:
Paul Taylor wrote:
"David L. Jones" <altzone@gmail.com> wrote in message
How are you generating a 1ns pulse with a generator that is only
capable of generating a 25ns pulse at best?
http://www.amplifierrentals.com/Equipment/HP/8011A.htm

Dave :)

Derhhh sorry Dave you are right i misread the scope it is in fact 1usec
timebase not as i previously thought 1ns must get my eyes tested.

The problem is not misreading the scope, but failure to sanity check
the reading.

You need to develop a sense of "that (probably) can't be right" based
on knowledge of what might reasonably be happening.

I do normally use that type of approach i have been having some off days, i

not sure if any of you guys are from the UK but at the moment we are
experiencing a mini heatwave temperature in my room is up at 36 degrees now
that coupled with the fact that the nights are up in the low 20 hence lack
of sleep for the last week has some what blurred my head not trying to make
excuses or anything. i borrowed the pulse generator from another department
and asked the guy for one to generate a 5ns pulse that was what i was given
i should of check the data sheet i guess my fault i felt an absolute idiot
but there what is down is down, i learnt from my mistake.
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Bill Sloman
electronics forum Guru


Joined: 12 May 2005
Posts: 1080

PostPosted: Fri Jul 21, 2006 9:53 am    Post subject: Re: Count 1ns pulse Reply with quote

Paul Taylor wrote:
Quote:
bill.sloman@ieee.org> wrote in message
news:1153431871.396180.99330@m73g2000cwd.googlegroups.com...

ian field wrote:
bill.sloman@ieee.org> wrote in message
news:1153414810.930979.13180@m79g2000cwm.googlegroups.com...

Phil Allison wrote:

snipped usual rubbish

We have to be kind to Phil. He lives in Sydney, and can't get refugee
status anywhere else.

--
Bill Sloman, Nijmegen


He'll burst a vessel if he keeps on like that!!!!!

We can hope, but he's survived long periods of mouth-frothing rage
before, so one can't be too optimistic.

--
Bill Sloman, Nijmegen


Isn't it a shame that a certain individual trying to ruin the thread, I
reckon Phil must lead such a sad and boring existence that he has to try and
insult every one else to make himself feel better!

Phil seek some help mate as Im sure that under all that bitter and twisted
attitude is a nice helpful guy waiting to get out and into the real world of
existence with normal people.

Phil can be very helpful within his areas of expertise, but he does
have a very short fuse, as you may have noticed, and once he gets
irritated, he stays irritated for several days at a time..

--
Bill sloman, Nijmegen
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Bill Sloman
electronics forum Guru


Joined: 12 May 2005
Posts: 1080

PostPosted: Fri Jul 21, 2006 10:04 am    Post subject: Re: Count 1ns Pulse Reply with quote

Paul Taylor wrote:
Quote:
"Bill Sloman" <bill.sloman@ieee.org> wrote in message
news:44bf9ea5$0$2017$ba620dc5@text.nova.planet.nl...
What sort of photomultiplier tube are you using to drive the AD7 amplifier
discriminator?

Photomultiplier data sheets usually list the typical single photon output
pulse width - it depends on the spread of the electron trajectories
through the dynode chain, and it is pretty reproducible.

Using the wrong voltage distribution down the dynodes can mess up the
pulse width - with fast focussed high gain tubes yo can need a lot of
voltage across the last few dynode to prevent the space chage associated
with the electrons from messing up the electric field and spreading out
the electrons.

--
Bill Sloman, Nijmegen

Hi bill the photomultiplier is supplied by Stockholm university which they
now have back, I don't have no data sheet on it as it is a old type one, I
heard back from the guy at electron tubes and basically he has said the same
as you! dependant on photomultiplier tube speed and biasing of the tube ect,
Im trying to pin him down on the minimum pulse width, he has said between
3ns and 15ns so if I work with 3ns then any type of photomultiplier tube
will work.

Fast focussed photomultipler tubes like the venerable Electron Tubes
9814 offer a typical pulse width fo 3nsec, and they are the fastest
tubes that you are likely to come across in your application.

Incidentally, Stockholm University ought to be able to identify the
tube used, and once you have got the manufacturer and part number,
getting hold of a data sheet isn't difficult - the photomultiplier
business isn't known for rapid change.

--
Bill Sloman. Nijmegen
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Paul Taylor
electronics forum beginner


Joined: 10 Feb 2005
Posts: 45

PostPosted: Fri Jul 21, 2006 10:14 am    Post subject: Re: Count 1ns Pulse Reply with quote

<bill.sloman@ieee.org> wrote in message
news:1153476249.706570.237390@i42g2000cwa.googlegroups.com...
Quote:
Fast focussed photomultipler tubes like the venerable Electron Tubes
9814 offer a typical pulse width fo 3nsec, and they are the fastest
tubes that you are likely to come across in your application.

Incidentally, Stockholm University ought to be able to identify the
tube used, and once you have got the manufacturer and part number,
getting hold of a data sheet isn't difficult - the photomultiplier
business isn't known for rapid change.

--
Bill Sloman. Nijmegen

Just emailed Stockholm to get a manufactures and part number on the

photomultiplier.
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