X-Ray Antenna

[ajnauleau]

Hey Everyone!

I am trying to build a point to point x-ray antenna, but I am fairly new to working with xrays. I managed to get my hand on an xray tube to mess around with a bit, but I am having some difficulties in getting to the next stage of my protoype.

The xray tube propogates xrays in every direction, and I would like to concentrate the xrays into a 10-20 μm point. I know this is possible as there is a device online that does the trick:

https://www.hamamatsu.com/resources/pdf/etd/L14351-02_TXPR1031E.pdf

I was thinking about concentrating the xrays through an electromagnetic coil, similar to how a cathode ray television send electrons onto the screen. Any other thoughts?

Thanks,
ajn

 

[rjenkinsgb]

Look again at the data for that device - on page 3; the X-Ray beam emission is spread over a 31' angle.

The "focus" in tube type X-Ray imagery system relates to the size of the electron beam impact site in the tube; how small and consistent the source is so it casts a finely detailed shadow through the object.
(Plus such as metal filters to block low energy photons & often a directional grid or "bucky" to block secondary emissions & off-axis photons, in medical imaging systems).

You cannot focus an electromagnetic wave in the ways you mention, as photons do not have a charge.
It must be done by the design of the emitter or by using an aperture to only allow emission in a certain direction.

As far as I am aware, there is no way you can focus the output of an x-ray tube, only block areas.

[And I hope you have all the correct protective equipment - even ignoring the voltages involved, the output from a commercial x-ray tube can be extremely dangerous over a wide area - including other buildings nearby, and you cannot see or easily detect it. If you are doing anything outside of a proper radiation-screened facility you could be exposing other people as well as yourself].


ps. If you have a "bare" surplus tube with a rotating disc anode, note that it should not be run without the anode motor coil setup in place an operating - the anode must be spinning before the tube has high voltage applied, so the electron beam does not overheat and pit any one point on the anode.
The drive coils for the anode are part of the overall casing, not the tube itself.

 

[unclejed613]

I managed to get my hand on an xray tube to mess around with a bit,

xrays are extremely dangerous to human tissue.... it's not something you "mess around" with...

 

[sagor1]

Possible Troll? No one in their right mind would simply fire up an x-ray tube and put their hands in front of it....

 

[unclejed613]

No one in their right mind would simply fire up an x-ray tube and put their hands in front of it....

well.... Professor Roentgen did, but he had no idea how dangerous it could be because he had just discovered xrays... i think most of his tubes were also pretty low power which probably helped keep him from doing real damage to himself... but yeah, there's good reason to have all the lead shielding in xray labs

 

[KeepItSimpleStupid]

I was thinking about concentrating the xrays through an electromagnetic coil, similar to how a cathode ray television send electrons onto the screen. Any other thoughts?

That's basically what an SEM does. In a vacuum, electron optics work. The SEM has a thermal source of electrons in the wheinhart cap. https://en.wikipedia.org/wiki/Wehnelt_cylinder Doubt it works for x-rays. The SEM detects the emitted X-rays with a scintilation grid.

In x-ray diffraction, it's more mechanical. e,g, https://en.wikipedia.org/wiki/Diffractometer Probaby more akin to how a monochometer works.

In an e-beam evaporator you basically have a 30 kW electron beam.

The lack of film for X-ray imaging, I think is really cool.

My area of expertise was operation and repair of a few SEM's. I set up EDS (energy dispersive x-ray analysis) and ebic (electron beam induced current). The ebeam system I basically repaired. There was an Auger/SIMS system I repaired too.



My optics background is really crappy.

 

[Dick Cappels]

It would be best if you explained your ultimate goal. There may be a way (not using X-Rays) to achieve this goal.

 

[Les Jones]

Is it possible that the OP does not know that X-rays and and X band microwave are not the same thing and he really means X band microwaves ?

Les.