electrospinning +15kV and -4kV = 19kV

On Thu, 19 Sep 2019 15:41:10 +0000 (UTC),
DecadentLinuxUserNumeroUno@decadence.org wrote:

And as far as your unrectified AC claim, I would only ask... "You do
know what a vacuum tube is, right? X-ray tubes are specifically
labelled "ANODE" and "CATHODE". Guess what they get energized by...
it is NOT AC."

An xray tube powered by a simple 60 Hz HV transformer gets AC and
self-rectifies.

https://www.orau.org/ptp/collection/xraytubescoolidge/valve2small.jpg

(Of course they got the "current flow" backwards)

 

[Winfield Hill]

DecadentLinuxUserNumeroUno@decadence.org wrote...

Do you even know what PARD is?

What is PARD? (I couldn't find it with Google.)


--
Thanks,
- Win

 

[Winfield Hill]

Winfield Hill wrote...

In fact, I haven't measured the ripple on my HV modules.
While I do have a stock of high-V caps, setting up the 20kV
measurement is painful to contemplate, so I'll probably just
take a pass. I am setting up a feedback-loop response test
today, using Ohmite SM108 500M 1% HV resistors. They're
2.1-inches long and rated at 20kV. I promise to be careful.

My 20kV supply module, an H20, made by ELDEC, seems to
have a very tightly regulated voltage, judging from my
measurements yesterday. So I suppose it might also
have low ripple. The last time we did this, we started
with +15kV and -4kV, or 19kV total, which worked well, so
we didn't make any changes. But I've heard that higher
voltages may be better to maximize the random lay-down of
a mat of nano-fibers, so we might turn it up towards our
25kV limit. Haha, maybe we should add ripple?


--
Thanks,
- Win

 

Correction:

"These low energy X-rays do NOT
make it through the PT to the detector"

I should know better then to type when I have a professor talking to me.

Steve

 

On 19 Sep 2019 08:58:50 -0700, Winfield Hill <winfieldhill@yahoo.com>
wrote:

DecadentLinuxUserNumeroUno@decadence.org wrote...

Do you even know what PARD is?

What is PARD? (I couldn't find it with Google.)

Periodic And Random Disturbances, another term for "noise."

Also means "good buddy."

 

On Thu, 19 Sep 2019 15:10:36 +0000 (UTC),
DecadentLinuxUserNumeroUno@decadence.org wrote:

jlarkin@highlandsniptechnology.com wrote in
news:9847oeldtng5n72gd26ahde4l5scsr5as3@4ax.com:

It's still line-of-sight xray photons. No focussing optics, no
chromatic effects, just pure geometry. Acceleration voltage has
almost no effect on image quality.


Oh but there most certainly is focussing optics.

X-rays are focused by Aluminum lenses.

I did not say that acceleration voltage had an effect. I said that
ripple does.

Here's one reference to an aluminum focussing lens. It doesn't sound
like it would be very sensitive to tube voltage.

Xray tube spectrum isn't very sensitive to voltage anyhow.

 

jlarkin@highlandsniptechnology.com wrote in
news:9v87oep97bnb53o9omkh19vkjhreda3c50@4ax.com:

Here's one reference to an aluminum focussing lens. It doesn't
sound
like it would be very sensitive to tube voltage.

Xray tube spectrum isn't very sensitive to voltage anyhow.

I never said that the lens would "be sensitive to tube voltage".

The e-beam creates the x-ray flux prior to the beam manipulation.
The image noise is also there prior to steerage.

Damn, Johnny... you look even funnier when you are grasping at
straws.

 

sroberts6328@gmail.com wrote in news:2ab209fe-b287-4a5c-af8e-
62112af2bb52@googlegroups.com:

> With all due respect, Xrays are not focused by aluminum lenses.

With all due respect, x-rays are indeed focussed by using Aluminum
lenses and grazing incidence 'mirrors'. Just not all machine designs
incorporate it in that way.

Aluminum is *almost* transparent to x-rays. There is your key.

Your CT experience uses coils, IIRC.

Sounds like you are 'brand specific' or 'type specific' and that is
how *that* machine works. You cannot possibly think that all x-ray
generation uses the nmethod you describe.

I have seen them as small as 4kV, and Los Alamos had us build a
50kV supply for them. A single ended design. The 180kV ECG
contracted supply we made was for the machines the airports were
using *at that time* and is was a dual 90kV monster supply using a
huge tube with a Palladium target anode.

 

jlarkin@highlandsniptechnology.com wrote in
news:i797oeto0vu98k3l6anagjor0dh2moqb3h@4ax.com:

On Thu, 19 Sep 2019 15:41:10 +0000 (UTC),
DecadentLinuxUserNumeroUno@decadence.org wrote:


And as far as your unrectified AC claim, I would only ask... "You
do know what a vacuum tube is, right? X-ray tubes are
specifically labelled "ANODE" and "CATHODE". Guess what they get
energized by... it is NOT AC."

An xray tube powered by a simple 60 Hz HV transformer gets AC and
self-rectifies.

https://www.orau.org/ptp/collection/xraytubescoolidge/valve2small.j
pg

(Of course they got the "current flow" backwards)

Nope. Anode is positive. Electron beam moves from negative to
positive. That angled plate in the tube in that diagram is the
anode... is the metal target of the e-beam. Is the positive node.

This ain't hole flow.

 

Winfield Hill <winfieldhill@yahoo.com> wrote in
news:qm08jq07du@drn.newsguy.com:

DecadentLinuxUserNumeroUno@decadence.org wrote...

Do you even know what PARD is?

What is PARD? (I couldn't find it with Google.)

Periodic and random deviation

It is an old linear supply term.

<https://www.tek.com/document/application-note/understanding-linear-
power-supply-specifications>

 

Winfield Hill <winfieldhill@yahoo.com> wrote in
news:qm08b2072d@drn.newsguy.com:

Winfield Hill wrote...

In fact, I haven't measured the ripple on my HV modules.
While I do have a stock of high-V caps, setting up the 20kV
measurement is painful to contemplate, so I'll probably just
take a pass. I am setting up a feedback-loop response test
today, using Ohmite SM108 500M 1% HV resistors. They're
2.1-inches long and rated at 20kV. I promise to be careful.

My 20kV supply module, an H20, made by ELDEC, seems to
have a very tightly regulated voltage, judging from my
measurements yesterday. So I suppose it might also
have low ripple. The last time we did this, we started
with +15kV and -4kV, or 19kV total, which worked well, so
we didn't make any changes. But I've heard that higher
voltages may be better to maximize the random lay-down of
a mat of nano-fibers, so we might turn it up towards our
25kV limit. Haha, maybe we should add ripple?

electro-phoresis is not affected by ripple either. It simply works
by the attractive force of the voltage, so any ripple has zero
effect. This too counts on net attraction and any noise is an order
of magnitude down in the mud of that attractive force.

You increasing voltage makes the needle have a higher 'pressure'
against it. EMF attraction is what "pressure" means in this case.

X-rays, OTOH, are the result of a direct collision between an
accelerated electron beam, and the surface of the anode. A nice,
hard collision. E-phoresis and your needle tech are far more
'mushy' and therefore not susceptible to noise in the attraction
supply. Electrons hitting a metal and exhibiting x rays directly off
that impingement means each electron is likely involved in that flux
generation so noise can be 'seen' much more easily in the end
product.

Hey, I know... maybe you should get some of that fake hair spray
with the little fibers in it. Spray that on with a charge in place.
You atre essentially talking about tightly controlled 'powder
coating' here. Except yours is single strand instead of powder.

 

[John Larkin]

On Thu, 19 Sep 2019 09:16:11 -0700 (PDT), sroberts6328@gmail.com
wrote:

>With all due respect, Xrays are not focused by aluminum lenses. They are filtered by shaped aluminum disks or sheets, to prevent the PT from being exposed to the huge amount of low energy X-rays that comes off a typical tube anode, usually made of Tungsten with a touch of Iridium for toughening. These low energy X-rays do make it through the PT to the detector. Thus they just result in extra cumulative dose to the patient if not filtered out.

There do seem to be aluminum x-ray focussing refractive lenses, and
gold things too.

https://en.wikipedia.org/wiki/X-ray_optics#Focusing_optics

But the spectrum out of an xray tube doesn't change much with voltage.
I can't see how a bit of ripple could matter.

I did a bunch of work in EUV lithography. The ca 13 nm light doesn't
refract much, so the lenses are grazing-incidence things, look sort of
like a cross between a beer barrel and a diesel engine.

Aluminum, Nylon, and Beryllium are typical filters used in CT or real Time Imaging X-ray systems.

The Filters are also shaped to avoid hot spots at the detector array from scattering in the frame or from the tube's inherent beam profile. With 64 or 256 detectors in an CT machine array, normalizing the beam is important.

I'll give you an example based on one I worked on.

Modern medical CT machines use dual, split, supplies aka programmable PSUs that can source 80 to 120 Kvp at 10 to 900 mA adjustable. This supply is actually modulated as it spins round the patient with the detectors on the opposite side of the Rotor. 440 VAC slip rings around the patient supply the power. Modulating the supply is used to reduce dose, and it can change tube current very fast during a rotation based on a "prescan" of the PT or real time on the fly calculations.

The supply also provides an auxiliary voltage to drive a deflection plate next to the cathode to slightly move the X-ray beam to enhance resolution by shifting the beam around one detector width along the patient axis. That pulses like crazy

A high tube current such as 800 mA would be used in an emergency "once in a lifetime" scan to quickly find a bleed or injury in the ER. Normal doses are much lower, say 350 mA.

I spent a year as a CT Electronics Trainer...

I got CT scanned three times in the Zuckerberg ER [1]. They kept not
liking the results and sending me back. I don't remember much of that.

[1] he bought the hospital for his wife.

 

sroberts6328@gmail.com wrote in
news:334e5e35-968e-4260-a281-b83f396a8dd4@googlegroups.com:

Correction:

"These low energy X-rays do NOT
make it through the PT to the detector"

I should know better then to type when I have a professor talking
to me.

Steve

'than to type'.

It makes a completely different sentence.

You make it sound like you actually feel as though you should wait
until you know better, then type while your professor is talking.

Have you done this waiting then typing thing before?

 

[Winfield Hill]

DecadentLinuxUserNumeroUno@decadence.org wrote...

jlarkin@highlandsniptechnology.com wrote:

(Of course they got the "current flow" backwards)

Nope. Anode is positive. Electron beam moves from negative to
positive. That angled plate in the tube in that diagram is the
anode... is the metal target of the e-beam. Is the positive node.

This ain't hole flow.

They could have labeled the drawing electron flow,
rather than current flow.


--
Thanks,
- Win

 

[John Larkin]

On 19 Sep 2019 13:19:33 -0700, Winfield Hill <winfieldhill@yahoo.com>
wrote:

DecadentLinuxUserNumeroUno@decadence.org wrote...

jlarkin@highlandsniptechnology.com wrote:

(Of course they got the "current flow" backwards)

Nope. Anode is positive. Electron beam moves from negative to
positive. That angled plate in the tube in that diagram is the
anode... is the metal target of the e-beam. Is the positive node.

This ain't hole flow.

They could have labeled the drawing electron flow,
rather than current flow.

I've met techs who learned "electron flow" in the military, and then
later switched to conventional current notation. It wrecked them for
life.

 

[whit3rd]

On Thursday, September 19, 2019 at 8:10:44 AM UTC-7, DecadentLinux...@decadence.org wrote:

jlarkin@highlandsniptechnology.com wrote in
news:9847oeldtng5n72gd26ahde4l5scsr5as3@4ax.com:

It's still line-of-sight xray photons. No focussing optics, no
chromatic effects, just pure geometry. Acceleration voltage has
almost no effect on image quality.


Oh but there most certainly is focussing optics.

X-rays are focused by Aluminum lenses.

Not in any useful way, they aren't.

 

[Clifford Heath]

On 19/9/19 7:17 pm, Martin Brown wrote:

On 18/09/2019 15:32, jlarkin@highlandsniptechnology.com wrote:
AoE, at a mere 1170 pages, doesn't devote much time to Signals and
Systems; there are bits here and there. Any scientist should get a
separate outline of that.

The corresponding Swiss army knife of computing for scientists,
numerical analysis and basic signal processing is "Numerical Recipes" by
Press, Flannery, Teukolsky and Vettering which isn't a bad practical
introduction (although some of their code doesn't quite work and some
algorithms are obfuscated by FORTRAN array starts at 1 indexing). The
bibliography is fine though specialist newer texts are better.

Anything more than that and you are into university signal processing
texts like Digital Signal Processing by Prokalis & Manolakis (sp?) etc.

I've started on Lyon's book "Understanding Digital Signal Processing"
and like it. The explanations are more intuitive, less abstract math
(though still a primarily mathematical subject of course).

Anyone else like this book?

Clifford Heath.

 

[John Larkin]

On Fri, 20 Sep 2019 08:26:00 +1000, Clifford Heath
<no.spam@please.net> wrote:

On 19/9/19 7:17 pm, Martin Brown wrote:
On 18/09/2019 15:32, jlarkin@highlandsniptechnology.com wrote:
AoE, at a mere 1170 pages, doesn't devote much time to Signals and
Systems; there are bits here and there. Any scientist should get a
separate outline of that.

The corresponding Swiss army knife of computing for scientists,
numerical analysis and basic signal processing is "Numerical Recipes" by
Press, Flannery, Teukolsky and Vettering which isn't a bad practical
introduction (although some of their code doesn't quite work and some
algorithms are obfuscated by FORTRAN array starts at 1 indexing). The
bibliography is fine though specialist newer texts are better.

Anything more than that and you are into university signal processing
texts like Digital Signal Processing by Prokalis & Manolakis (sp?) etc.

I've started on Lyon's book "Understanding Digital Signal Processing"
and like it. The explanations are more intuitive, less abstract math
(though still a primarily mathematical subject of course).

Anyone else like this book?

Clifford Heath.

Haven't seen it. I like Signals And Systems For Dummies.

 

[Martin Brown]

On 19/09/2019 23:26, Clifford Heath wrote:

On 19/9/19 7:17 pm, Martin Brown wrote:
On 18/09/2019 15:32, jlarkin@highlandsniptechnology.com wrote:
AoE, at a mere 1170 pages, doesn't devote much time to Signals and
Systems; there are bits here and there. Any scientist should get a
separate outline of that.

The corresponding Swiss army knife of computing for scientists,
numerical analysis and basic signal processing is "Numerical Recipes"
by Press, Flannery, Teukolsky and Vettering which isn't a bad
practical introduction (although some of their code doesn't quite work
and some algorithms are obfuscated by FORTRAN array starts at 1
indexing). The bibliography is fine though specialist newer texts are
better.

Anything more than that and you are into university signal processing
texts like Digital Signal Processing by Prokalis & Manolakis (sp?) etc.

I've started on Lyon's book "Understanding Digital Signal Processing"
and like it. The explanations are more intuitive, less abstract math
(though still a primarily mathematical subject of course).

Dunno. I tend towards very mathematical treatments since I was mostly
working on the borderline between applied maths and theoretical physics.

At some point you need an algorithm that can be converted into a
computer program to execute it. Pictures and illustrations may help you
to get a qualitative feel for what is going on but at some point you do
have to knuckle down and do the mathematics.

That said libraries like NAGLIB are pretty much gold standard numerical
analysis and data processing tools if you have a license to use them:

https://www.nag.co.uk/content/nag-library

It is a lot more reliable than Numerical Recipes on the difficult edge
cases when there are hidden traps lurking in the simple algorithms. An
algorithm that works for 99% of cases is easy but nailing that last
awkward 1% or 0.1% can be incredibly difficult. In Excel 2007 first
release they ruined a perfectly good chart polynomial fit routine to
make it agree with another flawed implementation in their reference tool

Users screamed at them pretty soon after it came out!

--
Regards,
Martin Brown

 

John Larkin <jlarkin@highland_atwork_technology.com> wrote in
news:sef7oeptsgloti2d21fcmb36k8sv5q0krf@4ax.com:

But the spectrum out of an xray tube doesn't change much with
voltage. I can't see how a bit of ripple could matter.

It is not about "the spectrum". It is about the purity of the
stream.

The e beam striking the emissive target. Call it 'sputtering' if
you need to get a grasp on what happens. Clean, pure e-beam...
clean pure x-ray flux... cleaner imagery.

Noisey e-beam... noisey imagery.

Known fact. Sorry. I cannot really explain the mechanism. I can
theorize what the causal element is, but it is not about your
imagined spectrum/voltage thing. To me, it is likely more about how
the e-beam 'flux' emits from the cathode, on its way to the anode.
The ripple causes the electrons to dance off axis a bit.

Whatever the actual physics are, the fact remains that a clean DC
source makes cleaner images than a noisey one does. I do know that.
You seem to not know that, and I guess that intimidates you as you
have obsessively tried to bolster your feeling that it changes
nothing.

With an application for simple HV attraction, like as in e-
phoresis, noise would not change.

This application is NOT simply about attractive force. An actual,
hard electron beam is generated, and obviously noise in the
accelerated stream apparently makes a difference.

I am sure that a DC battery fired unit would be even cleaner.

So I would say that apparently the x ray imagery is affected by the
'noise floor'. IOW it is pretty sensitive if PS ripple makes a
notable difference... and it does.