Is an X-Ray emitting laser pointer possible?

[Blarg King]

It actually didn't occur to me that the current might be too low. If I pulled a module from an actual stun gun then I would agree, the current would likely be too low because it would likely meet some standards to reduce the risk of a stun gun killing someone. But these ebay modules are around 4-7$ each, and though some are advertised as "stun gun module", I'm somewhat doubtful they would have much in the way of current limiting. But that still doesn't mean they would have enough current I suppose.

Perhaps adding some high voltage capacitors to allow a charge to build up and then dump more current? Liven up your next disco with an xray strobelight...

 

[Alaskan]

Those cheap stun guns produce HV though arcing current through a coil, do they not? A high voltage AC pulse?

 

[paul1598419]

Regardless, they haven't the current to keep the HV from being pulled down by the lack of available current. I would think you'd want a DC HV supply to to use with an X-Ray tube and it needs to have enough current to keep the voltage from sagging.

 

[Seoul_lasers]

Those cheap stun guns produce HV though arcing current through a coil, do they not? A high voltage AC pulse?

Not all of the stunguns/tazers work in this manner. Some larger units use a voltage multiplier (cascade circuit), having taken a few apart. They are all most certainly HVDC (pulsed).

A cascade circuit will most certainly work for driving an X-ray tube. Surprisingly it takes little current to make even a detectable amount of x-rays provided you have enough potential. You can also operate an X-ray tube in cold cathode mode. Perhaps, not as efficient as running a dedicated source of electrons (boiling them off a hot cathode) but it still works.


Below is an example of a crookes tube being run off a wimshurst machine. The current on such a device is maybe 50-100uA range at best and possibly heading towards a 1mA with the leyden jars. The potential is around ~140kV.

 

[paul1598419]

No doubt you can measure X-Rays, but in order to get significant amounts from a hot cathode tube, wouldn't you need more current than is possible with these static or stun guns running off of small alkaline batteries?

 

[cyberdoc]

Hmmmm. Interesting video. I just can’ t understand why public schools may have a problem with this unshielded demonstration in their classrooms? :crackup:


-cd

 

[Alaskan]

COOL-X X-Ray Generator ? Amptek ? X-Ray Detectors and Electronics

 

[Seoul_lasers]

No doubt you can measure X-Rays, but in order to get significant amounts from a hot cathode tube, wouldn't you need more current than is possible with these static or stun guns running off of small alkaline batteries?

yes, generally speaking. You can still develop film with the x-rays made by Carl Willis in the Crookes tube demo.... but of course that pales in comparison to what could be made with a large hospital sized tube where X-ray photon potential energy is around 80KeV (normally) -100KeV Peak

The tubes that have a hot cathode on them are meant to be driven at higher current because the idea is to have a stable
X-ray output for imaging purposes, like in a dental x-ray. Especially CAT and CT scans and deep body cavity imaging... that also includes a rotating anode on some larger tubes due to the intense heating.

Lower current ( even with a source of thermionic emission / electrons) while being able to produce x-rays, causes an unstable emission in tubes. (not as much potential energy to get the X-ray emission from the target surface)



An aside, but related...
Cold Cathode X-ray tubes exist, (flash X-ray) but are generally limited for ballistics and detonics due to their high output energies . They require pulsed voltage and current via VERY LARGE capacitor discharge. Pulses generally last 10-20ns in length.
The current is in the 1-10kA range. The largest of these tubes run 750kV - 1.2MV at 10kA ... each burst giving a dose of 65mR -120mR (650uSv -1.2mSv) at 1M and their output can penetrate 6-10cm of steel plate. Ouch...


:can:

 

[DashApple]

Only thing X ray related I keep when I do find them is the X ray transformers used to produce the HV AC : D.

 

[WizardG]

I remember well when I was working on older TV sets, back when I was a teenager, the time an old zenith with a bad HV regulator circuit gave my face a lovely X-ray tan. I was bright red, except for the shadow from the frame of my glasses.

 

[paul1598419]

I remember well when I was working on older TV sets, back when I was a teenager, the time an old zenith with a bad HV regulator circuit gave my face a lovely X-ray tan. I was bright red, except for the shadow from the frame of my glasses.

Never saw this problem during the time I was doing television work. Saw many sets from the 60s up to the early 70s. IIRC, 6EN4 was a typical HV regulator tube. You are actually the first person to claim having this happen to my knowledge. I can't imagine how this actually happened as the CRTs were shielded to a degree.

 

[Blarg King]

Never saw this problem during the time I was doing television work. Saw many sets from the 60s up to the early 70s. IIRC, 6EN4 was a typical HV regulator tube. You are actually the first person to claim having this happen to my knowledge. I can't imagine how this actually happened as the CRTs were shielded to a degree.

There were incidents where faulty HV supplies in TVs would run at too high a voltage and cause TV sets to produce decent amounts of Xrays. Modern TV HV supplies have multiple failsafes to prevent overvoltage as a result of this.