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Re: [Phys-l] [tap-l] X-Rays Detected From Scotch Tape



"There are conflicting accounts of his discovery because Röntgen had his lab notes burned after his death, but this is a likely reconstruction by his biographers."

http://en.wikipedia.org/wiki/X-ray#Wilhelm_R.C3.B6ntgen



Curious, as he "proved" they are transverse by double scattering w/ carbon blocks.

He had available Toepler pumps -- I suppose a well made one would attain a pressure of about two milliTorr*. (again about the min. p. of an oil vane pump)



* saturated vapour p. of Hg at ~ 20 C



bc wonders what is Brian's source.



On 2008, Oct 23, , at 19:30, Brian Whatcott wrote:

As to the hardness of vacuum needed for the production of x-rays from an
electron discharge, perhaps one could look over Roentgen's notes?

Brian W


At 07:08 PM 10/23/2008, Bernard Cleyet wrote:
On about < the mean free path of the electrons in the residual gas.
Given in the article 0.002" (~ 51 E-6 m), so go figger.

Not the best for calculation:


http://mysite.du.edu/~jcalvert/phys/scat.htm

bc skimmed


On 2008, Oct 23, , at 14:18, Marc "Zeke" Kossover wrote:

I wonder how hard the vacuum needs to be? 10^-5? 10^-8?

Zeke

----- Original Message ----
From: Tom Kramer <tmkramer@alum.mit.edu>
To: tap-l@lists.ncsu.edu
Sent: Thursday, October 23, 2008 1:59:19 PM
Subject: [tap-l] X-Rays Detected From Scotch Tape

My wife saw this on aol:

<http://news.aol.com/article/x-rays-detected-from-scotch-tape/ 221637>




Brian Whatcott Altus OK Eureka!

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