Electrical Engineering - HV capacitors which emit x-rays?!!!

Author

HV capacitors which emit x-rays?!!!

billb@eskimo.com

2006-11-27, 3:25 am

I stumbled across an odd idea.

If a home-built stacked-plate capacitor is operated with high-volt
pulses, the thin air film trapped between the foils and the dielectric
sheets should glow violet. (I verified this idea using a quickie test
device made from a thin glass bowl, foil on the bottom, and salt-water
on the top. Sure enough, there's a purple glow shining from the foil
surface under the glass.)

Ah, but we know that plasma leads to pumping: both from ion pump
effects where gas molecules embed into metal surfaces, and also from N2
turning into metal nitrides, and O2 turning into metal oxides. (Plasma
does chemistry.) And there's not much air involved, so the pressure
should plummet fairly fast.

So I use silicone to seal up the edges of the foil on the
glass/saltwater cap, then run it for awhile. Sure enough, the purple
glow changes color after a few minutes. Becomes greyish. Maybe even
greenish. Might be a pressure change, or it might be contamination
from the silicone caulk. I place it on the large ion chamber of a GM
counter, but don't detect any rise above background count. I could
keep running it for lots more minutes, but I'd burn down the contacts
of my little "vacuum tester TC."

So... any Tesla coil capacitor which is sealed but which isn't
vacuum-impregnated with oil is going to have plasma-filled air films,
and the internal pressure is going to drop over time. And in theory,
over time these air layers might pump down to non-glowing vacuum and
then start emitting soft x-rays!

What to do? The whole problem might be a crackpot idea. It's all
speculation (except for my glass/saltwater test.) Suggestion: paint
the outside of your home-built well-sealed Tesla coil stacked-plate
capacitors with ZnS glow-in-dark paint. Run them in a darkened room
separate from the bright streamers and spark gap. Or instead make an
xray alarm: a solar cell as sensor, painted with fluorescent paint and
embedded in black epoxy or silicone.

First one to detect a dim green glow wins a prize: slightly irradiated
gonads!

If the effect ever proves real, then does it mean we can replace the
vacuum tube in the dentist office with a bunch of aluminum foil layers
with spontaneously-appearing vacuum inside? (And would a
cylindrically wrapped capacitor act as a line-source of x-rays?)

((((((((((((((((((((((( ( ( (o) ) ) )))))))))))))))))))))))
William J. Beaty Research Engineer
beaty@chem.washington.edu UW Chem Dept, Bagley Hall RM74
billb@eskimo.com Box 351700, Seattle, WA 98195-1700
ph425-222-5066 http//staff.washington.edu/wbeaty/

Sorcerer

2006-11-27, 9:25 am

<billb@eskimo.com> wrote in message
news:1164607451.706157.259710@14g2000cws.googlegroups.com...
|I stumbled across an odd idea.
|
| If a home-built stacked-plate capacitor is operated with high-volt
| pulses, the thin air film trapped between the foils and the dielectric
| sheets should glow violet. (I verified this idea using a quickie test
| device made from a thin glass bowl, foil on the bottom, and salt-water
| on the top. Sure enough, there's a purple glow shining from the foil
| surface under the glass.)
|
| Ah, but we know that plasma leads to pumping: both from ion pump
| effects where gas molecules embed into metal surfaces, and also from N2
| turning into metal nitrides, and O2 turning into metal oxides. (Plasma
| does chemistry.) And there's not much air involved, so the pressure
| should plummet fairly fast.
|
| So I use silicone to seal up the edges of the foil on the
| glass/saltwater cap, then run it for awhile. Sure enough, the purple
| glow changes color after a few minutes. Becomes greyish. Maybe even
| greenish. Might be a pressure change, or it might be contamination
| from the silicone caulk. I place it on the large ion chamber of a GM
| counter, but don't detect any rise above background count. I could
| keep running it for lots more minutes, but I'd burn down the contacts
| of my little "vacuum tester TC."
|
|
| So... any Tesla coil capacitor which is sealed but which isn't
| vacuum-impregnated with oil is going to have plasma-filled air films,
| and the internal pressure is going to drop over time. And in theory,
| over time these air layers might pump down to non-glowing vacuum and
| then start emitting soft x-rays!
|
| What to do? The whole problem might be a crackpot idea. It's all
| speculation (except for my glass/saltwater test.) Suggestion: paint
| the outside of your home-built well-sealed Tesla coil stacked-plate
| capacitors with ZnS glow-in-dark paint. Run them in a darkened room
| separate from the bright streamers and spark gap. Or instead make an
| xray alarm: a solar cell as sensor, painted with fluorescent paint and
| embedded in black epoxy or silicone.
|
| First one to detect a dim green glow wins a prize: slightly irradiated
| gonads!
|
|

|
|
| If the effect ever proves real, then does it mean we can replace the
| vacuum tube in the dentist office with a bunch of aluminum foil layers
| with spontaneously-appearing vacuum inside? (And would a
| cylindrically wrapped capacitor act as a line-source of x-rays?)
|
| ((((((((((((((((((((((( ( ( (o) ) ) )))))))))))))))))))))))
| William J. Beaty Research Engineer
| beaty@chem.washington.edu UW Chem Dept, Bagley Hall RM74
| billb@eskimo.com Box 351700, Seattle, WA 98195-1700
| ph425-222-5066 http//staff.washington.edu/wbeaty/

Carry on testing. I'd suggest using a TV LOPT if you have equipment
problems.
http://www.worldinnovations.co.uk/m...ategory_from=14

Michael Moroney

2006-11-27, 1:25 pm

I don't know about that, but I do remember a "science experiments" book
from my high school library that suggested using a color television high
voltage rectifier tube as an X-ray source.

That source (plus the fact no book would _dare_ suggest any such thing
nowadays) dates the book.

Salmon Egg

2006-11-27, 1:25 pm

On 11/26/06 10:04 PM, in article
1164607451.706157.259710@14g2000cws.googlegroups.com, "billb@eskimo.com"
<billb@eskimo.com> wrote:

> I stumbled across an odd idea.
>
> If a home-built stacked-plate capacitor is operated with high-volt
> pulses, the thin air film trapped between the foils and the dielectric
> sheets should glow violet. (I verified this idea using a quickie test
> device made from a thin glass bowl, foil on the bottom, and salt-water
> on the top. Sure enough, there's a purple glow shining from the foil
> surface under the glass.)
>
> Ah, but we know that plasma leads to pumping: both from ion pump
> effects where gas molecules embed into metal surfaces, and also from N2
> turning into metal nitrides, and O2 turning into metal oxides. (Plasma
> does chemistry.) And there's not much air involved, so the pressure
> should plummet fairly fast.
>
> So I use silicone to seal up the edges of the foil on the
> glass/saltwater cap, then run it for awhile. Sure enough, the purple
> glow changes color after a few minutes. Becomes greyish. Maybe even
> greenish. Might be a pressure change, or it might be contamination
> from the silicone caulk. I place it on the large ion chamber of a GM
> counter, but don't detect any rise above background count. I could
> keep running it for lots more minutes, but I'd burn down the contacts
> of my little "vacuum tester TC."
>
>
> So... any Tesla coil capacitor which is sealed but which isn't
> vacuum-impregnated with oil is going to have plasma-filled air films,
> and the internal pressure is going to drop over time. And in theory,
> over time these air layers might pump down to non-glowing vacuum and
> then start emitting soft x-rays!
>
> What to do? The whole problem might be a crackpot idea. It's all
> speculation (except for my glass/saltwater test.) Suggestion: paint
> the outside of your home-built well-sealed Tesla coil stacked-plate
> capacitors with ZnS glow-in-dark paint. Run them in a darkened room
> separate from the bright streamers and spark gap. Or instead make an
> xray alarm: a solar cell as sensor, painted with fluorescent paint and
> embedded in black epoxy or silicone.
>
> First one to detect a dim green glow wins a prize: slightly irradiated
> gonads!
>
>

>
>
> If the effect ever proves real, then does it mean we can replace the
> vacuum tube in the dentist office with a bunch of aluminum foil layers
> with spontaneously-appearing vacuum inside? (And would a
> cylindrically wrapped capacitor act as a line-source of x-rays?)
>
> ((((((((((((((((((((((( ( ( (o) ) ) )))))))))))))))))))))))
> William J. Beaty Research Engineer
> beaty@chem.washington.edu UW Chem Dept, Bagley Hall RM74
> billb@eskimo.com Box 351700, Seattle, WA 98195-1700
> ph425-222-5066 http//staff.washington.edu/wbeaty/
>

I will try to discourage you. The light you see is probably corona. You need
to have high energy electrons (tens of keV's) to get any x-rays with
penetrating capability. Electrons traveling in a gas, ionized or not, will
just not reach sufficient energy because of collisions with air molecules.
If you end up gettering the air to get a vacuum you will not get electrons
except from photoemission or field emission. If you apply a voltage high
enough to achieve that, you are likely to destroy your metal coatings well
before you get x-rays.

A similar technique has been used for image intensification. In that case,
you might get electron energy in the tens of eV's. Look up image
intensifiers.

Bill
-- Fermez le Bush

Double-A

2006-11-27, 1:25 pm

JoeBloe

2006-11-27, 1:25 pm

On 26 Nov 2006 22:04:11 -0800, billb@eskimo.com Gave us:

> slightly irradiated
>gonads!

Whenever an electron beam (even a leak discharge) or plasma strikes
a metal surface x-rays are emitted.

It's a rule.

JoeBloe

2006-11-27, 1:25 pm

On Mon, 27 Nov 2006 17:52:05 +0000 (UTC),
moroney@world.std.spaamtrap.com (Michael Moroney) Gave us:

>I don't know about that, but I do remember a "science experiments" book
>from my high school library that suggested using a color television high
>voltage rectifier tube as an X-ray source.
>
>That source (plus the fact no book would _dare_ suggest any such thing
>nowadays) dates the book.

Bone up on the forum you invade.

Quote who you are replying to.

http://tools.ietf.org/html/rfc1855
http://en.wikipedia.org/wiki/Top-posting

Don Klipstein

2006-11-27, 5:25 pm

In article <20cmm29bqpuen1bpv67e53ulbm2fgvlr1t@4ax.com>, JoeBloe wrote:
>On 26 Nov 2006 22:04:11 -0800, billb@eskimo.com Gave us:
>
>
> Whenever an electron beam (even a leak discharge) or plasma strikes
>a metal surface x-rays are emitted.
>
> It's a rule.

Do consider the kinetic energy of free electrons. In corona in air,
that's going to be only a couple to a few eV. I don't see silicone being
airtight enough to improve upon that much from metal reacting with air
unless you have a vacuum pump hooked up and running.
Even if you do remove all oxygen and nitrogen, there will be argon - at
a pressure greater than that inside most fluorescent lamps.

- Don Klipstein (don@misty.com)

Dirk Bruere at NeoPax

2006-11-27, 5:25 pm

billb@eskimo.com wrote:
> I stumbled across an odd idea.
>
> If a home-built stacked-plate capacitor is operated with high-volt
> pulses, the thin air film trapped between the foils and the dielectric
> sheets should glow violet. (I verified this idea using a quickie test
> device made from a thin glass bowl, foil on the bottom, and salt-water
> on the top. Sure enough, there's a purple glow shining from the foil
> surface under the glass.)
>
> Ah, but we know that plasma leads to pumping: both from ion pump
> effects where gas molecules embed into metal surfaces, and also from N2
> turning into metal nitrides, and O2 turning into metal oxides. (Plasma
> does chemistry.) And there's not much air involved, so the pressure
> should plummet fairly fast.
>
> So I use silicone to seal up the edges of the foil on the
> glass/saltwater cap, then run it for awhile. Sure enough, the purple
> glow changes color after a few minutes. Becomes greyish. Maybe even
> greenish. Might be a pressure change, or it might be contamination
> from the silicone caulk. I place it on the large ion chamber of a GM
> counter, but don't detect any rise above background count. I could
> keep running it for lots more minutes, but I'd burn down the contacts
> of my little "vacuum tester TC."
>
>
> So... any Tesla coil capacitor which is sealed but which isn't
> vacuum-impregnated with oil is going to have plasma-filled air films,
> and the internal pressure is going to drop over time. And in theory,
> over time these air layers might pump down to non-glowing vacuum and
> then start emitting soft x-rays!
>
> What to do? The whole problem might be a crackpot idea. It's all
> speculation (except for my glass/saltwater test.) Suggestion: paint
> the outside of your home-built well-sealed Tesla coil stacked-plate
> capacitors with ZnS glow-in-dark paint. Run them in a darkened room
> separate from the bright streamers and spark gap. Or instead make an
> xray alarm: a solar cell as sensor, painted with fluorescent paint and
> embedded in black epoxy or silicone.
>
> First one to detect a dim green glow wins a prize: slightly irradiated
> gonads!
>
>

Bob Weiss

2006-11-27, 5:25 pm

Chris Jones

2006-11-27, 5:25 pm

Bob Eld

2006-11-27, 8:25 pm

"Salmon Egg" <salmonegg@sbcglobal.net> wrote in message
news:C1906A92.4CC01%salmonegg@sbcglobal.net...
> On 11/26/06 10:04 PM, in article
> 1164607451.706157.259710@14g2000cws.googlegroups.com, "billb@eskimo.com"
> <billb@eskimo.com> wrote:
>
>
> I will try to discourage you. The light you see is probably corona. You
need
> to have high energy electrons (tens of keV's) to get any x-rays with
> penetrating capability. Electrons traveling in a gas, ionized or not, will
> just not reach sufficient energy because of collisions with air molecules.
> If you end up gettering the air to get a vacuum you will not get electrons
> except from photoemission or field emission. If you apply a voltage high
> enough to achieve that, you are likely to destroy your metal coatings well
> before you get x-rays.
>
> A similar technique has been used for image intensification. In that case,
> you might get electron energy in the tens of eV's. Look up image
> intensifiers.
>
> Bill
> -- Fermez le Bush

I agree, X-rays will not be generated because the electons in the corona
have lost most of their energy in molecular collisions with the gases
present. Secondly, even if X-rays were formed, they wold be very low energy
because the voltage is low by X-ray standards. At best, the photons could
only be a few kV or so and would barely penetrate a piece of paper.

JoeBloe

2006-11-28, 9:25 am

On Mon, 27 Nov 2006 20:05:02 +0000 (UTC), don@manx.misty.com (Don
Klipstein) Gave us:

>In article <20cmm29bqpuen1bpv67e53ulbm2fgvlr1t@4ax.com>, JoeBloe wrote:
>
> Do consider the kinetic energy of free electrons. In corona in air,
>that's going to be only a couple to a few eV. I don't see silicone being
>airtight enough to improve upon that much from metal reacting with air
>unless you have a vacuum pump hooked up and running.
> Even if you do remove all oxygen and nitrogen, there will be argon - at
>a pressure greater than that inside most fluorescent lamps.
>
> - Don Klipstein (don@misty.com)

The key then would be to laminate the plate segments to their
insulative layer with a vacuum process during construction. Should
probably bake out any water as well. THEN seal the edges of the plate
layers, and one could even pull a vacuum on that assembly prior to
cure.

smuggie

2006-11-28, 9:25 am

"Bob Eld" <nsmontassoc@yahoo.com> wrote in message
news:MZKah.18955$Sw1.378@newssvr13.news.prodigy.com...
>
> I agree, X-rays will not be generated because the electons in the corona
> have lost most of their energy in molecular collisions with the gases
> present. Secondly, even if X-rays were formed, they wold be very low
> energy
> because the voltage is low by X-ray standards. At best, the photons could
> only be a few kV or so and would barely penetrate a piece of paper.
>
>

Wrong,

harmful X-rays were well known side effect of the first color TVs in the
1950's, and also of some high voltage tubes.

Why do you think there is 30 pounds of LEAD in today's 27 inch TV tube ??

mrdarrett@gmail.com

2006-11-28, 1:25 pm

smuggie wrote:
> "Bob Eld" <nsmontassoc@yahoo.com> wrote in message
> news:MZKah.18955$Sw1.378@newssvr13.news.prodigy.com...
>
> Wrong,
>
> harmful X-rays were well known side effect of the first color TVs in the
> 1950's, and also of some high voltage tubes.
>
> Why do you think there is 30 pounds of LEAD in today's 27 inch TV tube ??

Isn't there a vacuum inside TV picture tubes?

Bill Beaty

2006-11-28, 1:25 pm

Michael Moroney wrote:
> I don't know about that, but I do remember a "science experiments" book
> from my high school library that suggested using a color television high
> voltage rectifier tube as an X-ray source.
>
> That source (plus the fact no book would _dare_ suggest any such thing
> nowadays) dates the book.

And anyway it doesn't work! Well, if you find an old enough tube I
guess
it does. In the 1970s they switched over to lead glass in the
rectifiers
and in the CRT faceplate.

If we ignore the cancer danger, x-rays aren't that bad. For example,
a typical dental x-ray head cannot give you an x-ray burn. It takes
a year or two to get enough of a dose to give the mildest burn, and
your skin will heal faster than it's damaged. It's like weak
sunlight:
too dim to get a sunburn.

((((((((((((((((((((((( ( ( (o) ) ) )))))))))))))))))))))))
William J. Beaty Research Engineer
beaty@chem.washington.edu UW Chem Dept, Bagley Hall RM74
billb@eskimo.com Box 351700, Seattle, WA 98195-1700
ph425-222-5066 http://staff.washington.edu/wbeaty/

Bill Beaty

2006-11-28, 1:25 pm

Don Klipstein wrote:
> Even if you do remove all oxygen and nitrogen, there will be argon - at
> a pressure greater than that inside most fluorescent lamps.

Definitely. But go look up "ion pump." Apparently they're common
in small high-vac systems. No moving parts.

If you have metal with high enough negative voltage, slowly it will
scavange up all the remaining gas as accelerated ions become
embedded.

On the other hand, if the mean free path for electrons is shorter than
the empty space inside the cap, then all you need is electrons and
a strong enough e-field.

((((((((((((((((((((((( ( ( (o) ) ) )))))))))))))))))))))))
William J. Beaty Research Engineer
beaty@chem.washington.edu UW Chem Dept, Bagley Hall RM74
billb@eskimo.com Box 351700, Seattle, WA 98195-1700
ph425-222-5066 http://staff.washington.edu/wbeaty/

Bill Beaty

2006-11-28, 1:25 pm

Salmon Egg wrote:

> I will try to discourage you. The light you see is probably corona.

Agreed.

> You need
> to have high energy electrons (tens of keV's) to get any x-rays with
> penetrating capability. Electrons traveling in a gas, ionized or not, will
> just not reach sufficient energy because of collisions with air molecules.

Wrong. What do you mean by "gas?" We have to consider the issue
of pressure and mean free path for electrons.

For example, the old-style Roentgen x-ray tubes would stop working
if pumped down to really hard vacuum. They did not operate by
field-emission alone, instead they required electrode collisions with
the
trace of gas ions remaining. Before GE/Coolidge introduced
hot-filament
x-ray tubes around the 1930s, non-filament medical x-ray tubes would
include
a small gas-generator (such as a piece of coal) in a glass side-arm.
If
the internal pressure decreased too much because of ion-pumping effect,

the coal-chunk could be warmed in order to restore the (low) pressure.

> If you end up gettering the air to get a vacuum you will not get electrons
> except from photoemission or field emission. If you apply a voltage high
> enough to achieve that, you are likely to destroy your metal coatings well
> before you get x-rays.

Yet the old-style Roentgen tubes worked just fine.

If we slowly reduced the electrode spacing in those old tubes, what
effects
would arise that could prevent proper operation?

On the other hand, the dielectric sheets exposed to plasma would spew
out
ions and raise the gas pressure. Even quartz would generate oxygen.
So
use intrinsic silicon wafers as the dielectric?

((((((((((((((((((((((( ( ( (o) ) ) )))))))))))))))))))))))
William J. Beaty Research Engineer
beaty@chem.washington.edu UW Chem Dept, Bagley Hall RM74
billb@eskimo.com Box 351700, Seattle, WA 98195-1700
ph425-222-5066 http://staff.washington.edu/wbeaty/

Salmon Egg

2006-11-28, 5:25 pm

On 11/28/06 9:54 AM, in article
1164736487.861220.243580@14g2000cws.googlegroups.com, "Bill Beaty"
<billb@eskimo.com> wrote:

>
> Salmon Egg wrote:
>
>
> Agreed.
>
>
> Wrong. What do you mean by "gas?" We have to consider the issue
> of pressure and mean free path for electrons.
>
> For example, the old-style Roentgen x-ray tubes would stop working
> if pumped down to really hard vacuum. They did not operate by
> field-emission alone, instead they required electrode collisions with
> the
> trace of gas ions remaining. Before GE/Coolidge introduced
> hot-filament
> x-ray tubes around the 1930s, non-filament medical x-ray tubes would
> include
> a small gas-generator (such as a piece of coal) in a glass side-arm.
> If
> the internal pressure decreased too much because of ion-pumping effect,
>
> the coal-chunk could be warmed in order to restore the (low) pressure.

Sorry about that. I agree. The mean free path has to be long enough for the
electron to gain energy between collisions. I was not thinking about that
for the small gaps at relatively high pressure found in capacitors.

Residual gas can help in the formation of electron beams. The ions can
neutralize space charge repulsion effects and help keep beams focused.

Bill
-- Fermez le Bush

mmeron@cars3.uchicago.edu

2006-11-28, 5:25 pm

In article <1164733656.306115.152810@j44g2000cwa.googlegroups.com>, mrdarrett@gmail.com writes:
>
>smuggie wrote:
>
>
>Isn't there a vacuum inside TV picture tubes?
>
Sure. And the electron energy is around 25-30 keV. that's
significant.

Mati Meron | "When you argue with a fool,
meron@cars.uchicago.edu | chances are he is doing just the same"

Rich Grise

2006-11-28, 8:25 pm

On Tue, 28 Nov 2006 09:07:36 -0800, mrdarrett wrote:
> smuggie wrote:
>
> Isn't there a vacuum inside TV picture tubes?

Yeah, but there's a bunch of lead dissolved in the glass envelope. I'd be
a little surprised if it was really 30 pounds, however.

Cheers!
Rich

Bill Beaty

2006-11-28, 8:25 pm

Salmon Egg wrote:
> Sorry about that. I agree. The mean free path has to be long enough for the
> electron to gain energy between collisions. I was not thinking about that
> for the small gaps at relatively high pressure found in capacitors.

If plasma effects cause the capacitor to pump itself down, and if the
(glass?) dielectric doesn't release too much gas under plasma
bombardment, then the pressure within the capacitor might drop quite
low.

Here's a 2005 paper where a small crude x-ray generator is made from a
2cm diameter PP plastic syringe pumped down to only 3e-2 Torr, with 2
to 3 KVDC applied. The photos show that it glows brightly. Apparently
with close electrode spacing you can get significant x-ray output, even
while the pressure is still high enough to give a bright visible
discharge. But they did use a 150um Be window to let the soft x-rays
get out. (Maybe even a neon sign produces x-rays, but they can't
penetrate the glass?)

The paper shows a spectrum with a big peak around 2KeV or so, and a
tail going up above 4KeV. I wonder if 2KeV x-rays would get through
the metal foils and dielectric layers of a stacked-plate capacitor?
If they do, then a large stack of layers would obviously contribute to
x-ray intensity. But unless hydrogen ions would rapidly get
ion-pumped deep into the metal foil layers, this whole plasma pump-down
trick might not work with plastic or waxpaper dielectrics.

Simple X-ray Emitter, Murakami et. al.
http://www.jstage.jst.go.jp/article...21_881/_article

((((((((((((((((((((((( ( ( (o) ) ) )))))))))))))))))))))))
William J. Beaty Research Engineer
beaty chem.washington.edu UW Chem Dept, Bagley Hall RM74
billb eskimo.com Box 351700, Seattle, WA 98195-1700
ph425-222-5066 http://staff.washington.edu/wbeaty/

JoeBloe

2006-11-28, 8:25 pm

On Tue, 28 Nov 2006 09:02:07 -0600, "smuggie" <spamless@nospam.com>
Gave us:

>Why do you think there is 30 pounds of LEAD in today's 27 inch TV tube ??

Not true. Who ever fed you that crap?

ALL CRT type TVs emit *some* x-rays. It is from the electron beam
striking the aperture grille (not lead either, btw). There are not
now, nor have there ever been emissions from the sides of the tube, so
no, there are NOT ANY 30 Lb lead linings in ANY CRTs.

Bill Beaty

2006-11-28, 8:25 pm

Salmon Egg wrote:

> Residual gas can help in the formation of electron beams. The ions can
> neutralize space charge repulsion effects and help keep beams focused.

WOW, take a look at this one:

Anomalous X-Ray Emission from Insulators 1968 Michitaka Terasawa
http://jpsj.ipap.jp/link?JPSJ/25/1199

Also:
Strong X-Ray Emission from Electrified Insulators 2004 Inada
http://www.jstage.jst.go.jp/article...21_877/_article

Insulators of quartz or aluminum oxide bombarded by 20KeV protons are
producing intense x-rays? Hey, maybe an "x-ray capacitor" wouldn't
need much of a vacuum, just some hydrogen ions and some DC. Terasawa
thinks the protons just provide an intense surface charge, then some
repetitive discharges down within the insulator provides electrons to
accelerate.

Here's another weird thing:

1cM x-ray generator runs off 9V battery
http://www.amptek.com/coolx.html

Electrons spewed out by a chilled pyroelectric crystal are hitting
copper foil and making 8KeV x-rays?!! Low pressure gas? Dang.
Gotta make me wunna does tings.

((((((((((((((((((((((( ( ( (o) ) ) )))))))))))))))))))))))
William J. Beaty Research Engineer
beaty chem.washington.edu UW Chem Dept, Bagley Hall RM74
billb eskimo.com Box 351700, Seattle, WA 98195-1700
ph425-222-5066 http://staff.washington.edu/wbeaty/

JoeBloe

2006-11-28, 8:25 pm

On 28 Nov 2006 17:30:41 -0800, "Bill Beaty" <billb@eskimo.com> Gave
us:

>Here's another weird thing:
>
> 1cM x-ray generator runs off 9V battery
> http://www.amptek.com/coolx.html
>
>Electrons spewed out by a chilled pyroelectric crystal are hitting
>copper foil and making 8KeV x-rays?!! Low pressure gas? Dang.
>Gotta make me wunna does tings.
>

That is cool!

I used to make a 9V in HVPS for an x-ray machine that was driven at
4kV. Our supply had less than 3mV of ripple at 4kV! That is like
0.000006% ripple!

Anyway, the customer said that the super clean HVDC drive is what
makes for a super clean x-ray flux, and that makes for super crisp,
high contrast ratio x-ray images.

I made the best X-ray supplies in the world. We even had LANL,
LLNL, JPL and others buying our super clean, ultra pure HVDC supplies.

I think I want one of the cases they show on that x-ray transducer.
It looks like it would hold my polonium sample just perfectly! ;-]

Salmon Egg

2006-11-29, 3:25 am

On 11/28/06 5:30 PM, in article
1164763841.181470.141140@n67g2000cwd.googlegroups.com, "Bill Beaty"
<billb@eskimo.com> wrote:

> Insulators of quartz or aluminum oxide bombarded by 20KeV protons are
> producing intense x-rays? Hey, maybe an "x-ray capacitor" wouldn't
> need much of a vacuum, just some hydrogen ions and some DC. Terasawa
> thinks the protons just provide an intense surface charge, then some
> repetitive discharges down within the insulator provides electrons to
> accelerate.

For the same energy, protons are much slower than electrons. Thus protons
will have lower acceleration than electrons even though protons lay down
higher energy density along their tracks compared to electrons. The lower
acceleration leads to much less bremsstrahlung than using electrons. This is
used to advantage at Loma Linda university to provide more intense and
localized radiotherapy without generation and scattering x-rays produced by
bremsstrahlung.

Electrons stopped by insulators and other materials will produce
bremsstrahlung. The usual interactions of electrons and matter will take
place (photoelectric effect and Compton scattering). The atomic number of
the medium will be important on the details of of these losses.

Bill
-- Fermez le Bush

whit3rd@gmail.com

2006-11-29, 3:25 am

JoeBloe wrote:
> On Tue, 28 Nov 2006 09:02:07 -0600, "smuggie" <spamless@nospam.com>
> Gave us:
>
>
>
> Not true. Who ever fed you that crap?
>
> ALL CRT type TVs emit *some* x-rays. It is from the electron beam
> striking the aperture grille (not lead either, btw).

Err... the faceplate of the typical color TV is LEADED GLASS, i.e. lead
oxide dissolved
in the silicate glass. It contains about 4 lb of lead, and it might
have total weight of
the glass equal 30 lb.

And the most important X-rays aren't from the aperture grille (which is
typically chrome/nickel/iron)
because those have mainly K line emission which is in the 4 keV range;
not low enough for
high number of photons, and not high enough to get through much
shielding. The most important
are from the phosphors (rare earth types) which have L edges at 8 keV
or so, which is a tad
more penetrating, as well as involving more candidate electrons per
atom.

Simple plasma (St Elmo's fire) doesn't get to high enough temperature
for significant
X-ray output, though some laser plasma techniques can achieve this.

John Gilmer

2006-11-29, 5:25 pm

> And anyway it doesn't work! Well, if you find an old enough tube I
> guess
> it does. In the 1970s they switched over to lead glass in the
> rectifiers
> and in the CRT faceplate.

There shouldn't be much radiation from the rectifiers. The current only
flows in the forward direction and the voltage drop shouldn't be big enough
for x-ray production.

The old sets used a shunt regulator for the high voltage. This definitely
could be a problem.

>
> If we ignore the cancer danger, x-rays aren't that bad. For example,
> a typical dental x-ray head cannot give you an x-ray burn. It takes
> a year or two to get enough of a dose to give the mildest burn, and
> your skin will heal faster than it's damaged. It's like weak
> sunlight:
> too dim to get a sunburn.
>
> ((((((((((((((((((((((( ( ( (o) ) ) )))))))))))))))))))))))
> William J. Beaty Research Engineer
> beaty@chem.washington.edu UW Chem Dept, Bagley Hall RM74
> billb@eskimo.com Box 351700, Seattle, WA 98195-1700
> ph425-222-5066 http://staff.washington.edu/wbeaty/
>

JoeBloe

2006-11-30, 3:25 am

On 29 Nov 2006 00:03:47 -0800, whit3rd@gmail.com Gave us:

>
>JoeBloe wrote:
>
>Err... the faceplate of the typical color TV is LEADED GLASS, i.e. lead
>oxide dissolved
>in the silicate glass. It contains about 4 lb of lead, and it might
>have total weight of
>the glass equal 30 lb.

No.... He said 30Lb of lead. That would be in addition to the
glass weight.
>
>And the most important X-rays aren't from the aperture grille (which is
>typically chrome/nickel/iron)
>because those have mainly K line emission which is in the 4 keV range;
>not low enough for
>high number of photons, and not high enough to get through much
>shielding. The most important
>are from the phosphors (rare earth types) which have L edges at 8 keV
>or so, which is a tad
>more penetrating, as well as involving more candidate electrons per
>atom.
>
>Simple plasma (St Elmo's fire) doesn't get to high enough temperature
>for significant
>X-ray output, though some laser plasma techniques can achieve this.

Electrons striking metal is all that is needed. There are target
materials that are better than others.

If a 25kV stream striking a palladium target gives off a flux, then
a single static spark into the same target will give of an emission as
well, it just may not be one we can easily detect or quantify. The
same event occurs in both cases, it's just that in the case of the
stream there are far more events.

LinkBot