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Re: [Phys-l] "excessive bounces" and a new thread base on a > five? year old one.



Yes and I've been cautioned by several, including Gate Keeper, to give fair warning and ensure antecedent info. is included.

bc, shamed.

"Speaking" of:

antecedent:

My first post was in response to Ludwig's query about the stats. from G-M pulses, and w/ included data for the two source method of determining dead time. I'm not certain if this (two source) was then or later or even possibly a p.c. (personal communication). To add to the story, I think it was JD who wrote: this lurker** was correct [Poisson] and added detail.

Anyway, the dead time I calculated was > one milisec. Always I've found dead times about one tenth that. Furthermore all the lab. manuals, etc. I've read recommend intense sources to reduce the time to obtain "good" stats. However, Ludwig's sources were very weak. So I spent VERY many hours measuring dead times at various rates and found, w/ similar to LK's rate, also long dead times. So then I measured the dead times w/ ~ the same rates (very low) of various tubes (my collection includes end window pencil ones to about two inch diameter rather long ''cosmic-ray" ones ***). They all were long times w/ the length being a positive function of the diameter. Not unexpected to me, as my thesis (MA) was on the reduction of electron attachment in a counter using multiple counters in the same envelope as the single comparison counter. My last, unfinished, experiment was to "artificially" reduce the cathode diameter by using a third intense source as background w/ the two weak measurement sources.**** For this I used a > two inch pancake G-M tube. I never got around to collecting the data and writing for publication in, say, The TPT.

The question:

Has anyone read about or explored this effect?



**not. I posted the same day that I became a member of the list, contrary to later read advice on list etiquette.
*** These are antiques constructed by the UCB shops before 1955 -- they work!
**** I'd already modified the maths for the background complication, because my bedroom background was a significant fraction of my source rates. I was limited to about six hour counts because of the diurnally varying background.

On 2009, Aug 20, , at 17:39, Brian Whatcott wrote:

[Offered with a smile]

It is as well that one searches the archives in BC's case - he has been
known to continue a thread out of the blue on a topic from several years
earlier! :-)

Brian W

Bernard Cleyet wrote:
¡Yo tambien!
bc has searched the archive (successfully) for antecedents**.
** parents of the deceased?

On 2009, Aug 20, , at 08:40, John Clement wrote:
Incidentally sometimes messages from this list do go astray. I have sometimes received missives which obviously started in the middle of a topic, and could never find the antecedents.
John M. Clement Houston, TX

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