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Re: NEON- X-RAY bombarder
Hi Tony, all,
My comments regarding the "Neon John" repost below:
>Original Poster: TeslaTec-at-webtv-dot-net (Tony R Greer)
>
>Hi All,
>
>Modern X-ray tubes operate with a hard vacuum. A hard vacuum is
>necessary so that the electrons will have a high probability of
>crossing the electrode gap without colliding with a gas molecule.
>Such collisions produce only heat and sometimes light. The
>original tubes that Crooks, Roentgen, etc worked with had soft
>vacuums in them and typically did not use a filament.
In fact, with the modern Coolidge tubes, you shouldn't see any greenish
fluorescence of the glass walls unless the tube is weak.
>The PEAK X-ray energy possible (which determines its
>penetrating power) is the peak voltage available for accelerating
>the X-rays. In the case of a 15KV bombarder, this would be 15,000
>volts RMS * 1.414 = 21.21 kv peak (for a sine wave.) A 21 KeV X-ray
>has almost no penetrating power.
Voltage and current are the keys to x-ray penetrating power!
For what it's worth, here's what I personally found at different voltages:
20 KV- barely detectable with Geiger counter using thin mica window tube;
30 KV- moderately detectable with counter; most x-rays absorbed by a sheet
of paper;
40 KV- easily detectable; penetrate several sheets of paper with ease; first
evidence of very faint fluorescence of x-ray screen in dark;
50 KV- easily penetrate paper, sheet metal and very thin lead; x-ray screen
showing moderate glowing in dark;
60 KV- penetrate stack of paper, thicker metal (die cast to 1/4 inch); x-ray
screen showing brighter glowing;
above 70 KV- difficult to stop without at least 1/4 inch thick lead; objects
easily discerned on screen
John Bowers