[Boatanchors] Thanks for Replies: Question: X-Rays from 3B28?
Fuqua, Bill L
wlfuqu00 at uky.edu
Wed Feb 18 20:54:04 EST 2015
Can someone tell me how 866A tubes produce x-rays with 15V cathode to plate voltage difference?
From: Boatanchors [boatanchors-bounces at puck.nether.net] on behalf of William [w_b_morton at hotmail.com]
Sent: Wednesday, February 18, 2015 6:05 PM
To: wb3fau55 at neo.rr.com; LM Picard
Subject: Re: [Boatanchors] Thanks for Replies: Question: X-Rays from 3B28?
Again, thanks to all who responded. I enjoyed reading the comments and getting educated on the amount of energy required to produce x-rays.
My question has been fully answered and I will go ahead and experiment with 3B28 tubes on my next project.
> Date: Wed, 18 Feb 2015 17:35:20 -0500
> From: wb3fau55 at neo.rr.com
> To: lmpicard at rogers.com
> Subject: Re: [Boatanchors] Thanks for Replies: Question: X-Rays from 3B28?
> CC: w_b_morton at hotmail.com; boatanchors at puck.nether.net
> Years ago, there were 866s, which were mercury vapor type, these had a nice blue/purple glow in operation. These had more x-ray emission than the 3B28s, which were replacements. The 3B28s are filled with Xenon gas, which is far less hazardous. As you have demonstrated, the low voltage would be no hazard at all. 73s Russ.
> ---- LM Picard <lmpicard at rogers.com> wrote:
> > The soft x-rays produced by 8kv - 17kv potential differences are referred to as grenz rays because the occupy a place in the electro-magnetic spectrum between ultraviolet rays and more conventional x-rays.
> > They lack penetrating power and may be attenuated to some extent by air and more efficiently by thin layers of metal.
> > The maximum energy of x-ray photons is determined by the potential difference between cathode and anode.
> > Most of the x-rays produced in a vacuum tube result from deceleration of electrons as they hit the target (anode). This type of radiation is called bremsstrahlung. Superimposed on the continuous bremsstrahlung distribution are “characteristic” emission lines that are specific to the composition of the target.
> > The efficiency of a target in giving rise to x-ray emissions is proportional to the square of its atomic number. Therefore heavier metals are much more efficient at generating x-rays than materials lower in the periodic table.
> > I have no information on the material composition of the elements in a 3B28. However, tubes designed for x-ray use typically have targets of tungsten (atomic number, 74) or molybdenum (atomic number 42). Copper has an atomic number of 29 and iron 26.
> > Since x-rays are ionizing radiation, they can be detected by Geiger counters.
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