electrospinning +15kV and -4kV = 19kV

John Larkin wrote in news: snipped-for-privacy@4ax.com:

node.

then

for

It doe not come from 'the military'. It was J. J. Thomson, the man who 'discovered' the electron.

It stems from decades of vacuum tube science, and being old enough to have been taught through that hardware before solid state. Solid state ushered in more 'facts'.

Some lightning does move from earth to sky, but is is *very* rare. Most leaves a charged sky (cloud), and 'sinks' into a 'fully grounded' Earth.

More negative... less negative... Some charge remains... The event is over until the next charge level gathers and gets released.

What is this... leyden jar stuff?

Reply to
DecadentLinuxUserNumeroUno
Loading thread data ...

whit3rd wrote in news: snipped-for-privacy@googlegroups.com:

That *must* be why they actually do it. Since it is so non-useful.

Reply to
DecadentLinuxUserNumeroUno

What does that mean?

Do you sputter the xray tube anode? How long does it last, being splattered onto the glass?

Makes no sense. The image is made of random xray photons. It doesn't matter how "pure" they are.

Uh, right.

Reply to
jlarkin

snipped-for-privacy@highlandsniptechnology.com wrote in news: snipped-for-privacy@4ax.com:

doesn't

Maybe the difference is that of a single exposure and that of live imagery.

It would not affect single exposures as they are a function of exposure time and dosage level.

It would affect frame by frame live imagery because the exposure is so short lived that the frame data gathered is affected. Maybe that is where it is.

You tell us, crazy Mr. Spectrumboy. (thank you, Adam).

Then there are 'quantum noise' affects with x ray realm as well. Are you familiar with those?

Now you will come back stating how it is not related. I never said it was.

Reply to
DecadentLinuxUserNumeroUno

Then I guess I imagined those people.

Then why did I pay them?

Reply to
John Larkin

John Larkin wrote in news: snipped-for-privacy@4ax.com:

to

You met 'techs' and that is where *they* learned it, but that does not mean that is where the paradigm came from. ' You say stupid shit, then follow up with retarded shit. I guess that makes you dumber than dogshit.

Reply to
DecadentLinuxUserNumeroUno

Short term variations in the intensity of the beam translate into variations in intensity from one pixel to the next. The "image" is created by array of pixels, where the information is contained in the variations in intensity from one pixel to the next.

Short term variations in the intensity of the beam as it moves from pixel to pixel show up as noise on the image.

Quite a while. The atoms that get "sputtered" off the target condense back onto it.

Their "purity" isn't the issue. The number of x-ray photons associated with each pixel is. The item being scanned influences the number of x-ray photons associated with each pixel.

That's your signal. The intensity of the beam at each point in the scan also influences the number of photons associated with each pixel in a way that has nothing to do with the nature of the object being imaged. That's noise.

He shouldn't have needed to. It's pretty obvious.

--
Bill Sloman, Sydney
Reply to
Bill Sloman

That's unkind ot dogshit.

--
Bill Sloman, Sydney
Reply to
Bill Sloman

Bill Sloman wrote in news: snipped-for-privacy@googlegroups.com:

At 45 degree angle of incidence, no atoms glean off. Xray flux, however, does.

The idiot is using the term sputter in the wrong context.

Not unusual for this dork. Sadly, he probably did it on purpose.

Even more sad... It is probably the right term. He just chose the wrong definition. Par for his course through this.

He is so stupid that he thought I was referring to vaporizing a metal onto a surface in a vacuum chamber. We ain't coating DVD platters here. Though something seems to have been deposited in his brain cavity. Mucking up his vision.

I referred to 'other than absolutely clean DC'. Noisey HVDC 'sputters' like an old badly running car trying to do its job.

Reply to
DecadentLinuxUserNumeroUno

The book is mathematical, just not exclusively so. It augments the math with diagrams to help give an intuitive understanding. Pretty hard to explain quadrature signals and negative frequency without the math, but the pictures help understand the math.

Clifford Heath

Reply to
Clifford Heath

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.

You take you fantasies seriously?

--
Bill Sloman, Sydney
Reply to
Bill Sloman

I had an interview in a auditorium before ten veteran trainers, ten sy stems engineers, three managers, and a emeritus VP of Engineering, to get t hat X=Ray job. The interview was competitive, and I was the last of five to go. Anyone working in the division could come, watch my presentation, a nd ask questions. Quite a few did.

I did a ten minute lesson on a topic of my choice, and then was grilled on my knowledge of teaching techniques, physics, detectors, noise, servo syst ems, for forty five more minutes.

Then there was the second interview, setting at a CT with the covers pulled and manuals out. I was the only one of the perspective employees who could explain how a resolver worked when presented with one. And I assure you most CTs have a massive resolver imbedded in the rotor.

I was offered the job over several experienced senior engineers because I knew the physics, and because I lugged in a one hundred pound switching la ser power supply and test equipment, on a cart, and used them in my demo le sson.

I resent the implication that I do not know my X-ray physics. I was part of a seven person teaching team that trained thirty FSEs on the system, fr om the ground up, on a sixty day course. Not only did we do CT, but we sat in on ultrasound, other clinical X-ray systems, and comparative courses on other manufacturer's hardware, including inspection systems. I had sixteen machines of different vintage to maintain in one teaching hall alone. At any time I could be sent out in the field in an emergency, on an actual med ical system.

Funny thing about clinical X-ray, competitors do maintain each others sys tems in parts of the world where the competitor has a presence and the prin cipal manufacturer did not. So you could say I faced outside review of my teaching. Plus I sat all the exams on the system three times.

Not to mention diagnosis was readying around 4000 lines of commented comm ands going to and from the rotor on CANBUS per rotation. So I have a damn g ood idea of what the PSU and detector was doing. The detector returned data at 5.6 gigabytes per second over an array of free space laser diodes into a RAID array. The detector team came in and gave us lectures, so we could make new lesson s for the students. The local R and D team used the training machines for t heir tests of new hardware, and ANY part I needed was shipped in over night or supplied from the warehouse next door within 24 hours. This let us put faults in any part of the system or let the students blow a board.

So you geniuses can read up on Dual Spectrum X-Ray, Helical Scan, forth and sixth gen CT, Bremsstrahlung and Characteristic Radiation, K line, MaS, detector adsorption profiles, Edge Filters, Filter Wheels, and independent setting of tube current irrespective of tube voltage, because I lived it f or twelve hour days, six days a week. Because the Junior trainer was the on e who had to come in on Saturdays and oversee the students who were behind, and test every machine in the hall.

In classical tube terms, the tube was actually a Pentode, Two cathodes, a f ocus cup, a deflection electrode, and an anode.

Because five years later, I can still remember how to uncrate, position, an d align the damn machine in my sleep, and diagram the phantom and its adsor ption curves. I know about the anode, because I can still quote the HU numb ers. Not a one of you has mentioned tube conditioning, and why the anode is heated before scans to stabilize its spectrum across the spot and to clean up the vacuum before a PT run.

I had to profile all the aluminum in the path to align it, I have a damn fi ne idea of what x-ray lenses can and can not do.

I used to love SED, but I get real tired of people shouting off on systems they do not have a clue on.

Steve

Reply to
sroberts6328

snipped-for-privacy@gmail.com wrote in news:55761669-fad9-4543-b7ce- snipped-for-privacy@googlegroups.com:

OK, this is bullshit.

I never made any such statement or inferrence.

The only thing I rufuted is your blanket statement that Aluminum is not used to "focus" and "shape the x-ray flux stream.

It is, in SOME designs.

Obviously not your CT scanners.

But even a simple web search shows that they indeed are used in other systems for that very purpose.

So maybe you 'learned' it way back in a day of older hardware, and or, your exposure to the entire gamut of devices and technology in use was limited to CT.

But no, dude. I know you are smart. I do not see you doing the same things as Larkin and some others with the moniker thing.

You iterate facts. I never disputed that.

Reply to
DecadentLinuxUserNumeroUno

formatting link

formatting link

Reply to
jlarkin

snipped-for-privacy@highlandsniptechnology.com wrote in news: snipped-for-privacy@4ax.com:

NO, you RETARDED FUCK. It is NOT THAT definition. NOT wiki, dipshit! USE A DICTIONARY, YOU PATHETIC WORM.

GOD DAMN BOY YOU ARE STUPID!!!

Reply to
DecadentLinuxUserNumeroUno

Getting an aluminum surface smooth enough to refract X-rays, and getting more 'focus' intensification than absorption-of-beam attenuation, are an unlikely pair of achievements.

I'm not sure what 'they actually do', but it isn't focusing.

Reply to
whit3rd

whit3rd wrote in news: snipped-for-privacy@googlegroups.com:

It does not require optical surface quality.

And the refraction is very weak, so they do not have the shape you would seemingly expect.

Since Al is transparent to x rays, there is very little attenuation. Your grasp of it is (apparently) an unlikely singular achievement. Other materials are used as well, such as Beryllium.

Quoted:

"The weak refraction of hard x rays in matter requires the radius of curvature R of the individual lenses to be small. The spherical approximation holds only for lenses with an aperture 2R0 that is much smaller than the radius of curvature R. Since for most x-ray lens designs the aperture 2R0 is comparable to or larger than the radius of curvature R, the spherical approximation no longer holds. Therefore, for high quality imaging applications, parabolic (aspherical) lenses need to be made."

When one uses optics to sharpen and manipulate visible spectrum light, refractive media must be used. It shapes the incoming "light". The manipulation is referred to as "focussing". The lens shapes and formulae are familiar to many modern day scientists, among which you seem to number. However...

With x rays and extremely small refractive indexes the suitable mediums required means that your normal perception of what "focussing" is has to be opened up a bit (apparently).

I found no problem accepting this information years ago when I received it, and even had no problem conceiving what "less refractive" means. I do not know why you are having a difficult time with it.

Reply to
DecadentLinuxUserNumeroUno

On Monday, 23 September 2019 10:26:26 UTC+1, snipped-for-privacy@decadence.org

There is a simple reason why it may be important to keep a stable accelerating voltage. In order to get a sharp image the spot size where the electron beam hits the target needs to be as small as possible. It is very likely that the focus of the electron beam will be affected by anode voltage, so if there is substantial ripple the average spot size will increase, reducing the sharpness of the final image.

John

Reply to
jrwalliker

snipped-for-privacy@gmail.com wrote in news: snipped-for-privacy@googlegroups.com:

I stated in a post that the target gets struck by the e-beam "noisily" in such a case and the electrons dance around as opposed to being a clean, straight stream.

But you got it. The same thing that makes a CRT anode supply produce better quality screen framesm makes the x ray flux in a nice, clean, linear manner.

That pretty much resolves it.

Ripple causes 'dancing' of the e-beam spot locale.

Maybe they should put adjustment e-field plates in the tube between the anode and cathode to pin point the spot. But that too would likely still not be as happy with a noisey HVDC supply than a clean one.

Reply to
DecadentLinuxUserNumeroUno

No, google it. There are aluminum (and other) focussing lenses for x-rays.

Reply to
jlarkin

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.