A Spark Chamber

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A Spark Chamber

Postby Viewmaster » Fri May 17, 2019 10:46 pm

Gary said......Seriously, I hear there is plenty of space in this forum for projects such as those to be shown off and I am sure every one here is as interested as I to see them.
……………..
OK folks , here we go......…

Back in the 1960's, and before, Spark Chambers were used to detect particles from outer space.
Many Science Museums had them working as they created visual interest, seeing the particle tracks
showing up as a series of sparks.

So, I have started to build a small circular one, whilst still working on the Trainorama and
a QCWSSTC (Qaisi Continuous Wave Solid State Tesla Coil.)

Whether at 86, I shall ever finish any of them is debatable!

My design of Spark Chamber is 200mm dia x 200mm long acrylic cylinder with acrylic end plates.
Power supply slung under base acrylic, from 15kV NST I stripped from my old SGTC.

Photo shows an initial assembly to see if everything fits.

10 ali plates spaced 20mm apart on nylon spacers and bolts with HV on alternate plates.
(plates not shown on photo )
Argon filled with telltale neoprene disc to show pressure increase as sparking will heat up gas. HV to be cut manually to start with. Maybe auto later.

Model railway valves for Argon inlet/air outlet.

Non pulsed HV to start with, as the first spark chambers had this so
this is old fashion stuff. (Pulsing the HV to micro secs is expensive and complicated )

Gas valves are on top with white hose to connect to Argon cylinder and regulator.
Orange lines are 15kV DC supply to ali plates.

Other photo shows rectification and smoothing of 15kV HV with bleeder resistors wound on acrylic tube
to ensure I don't get a belt from the capacitors when off.

spark chamber.JPG


power supply.JPG
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Re: A Spark Chamber

Postby Harry Dalek » Mon May 20, 2019 8:44 am

Interesting device Albert way beyond any thing I have ever thought about ,In fact never even heard about any thing like this existed .
Last edited by Harry Dalek on Sun May 26, 2019 9:15 am, edited 1 time in total.
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Re: A Spark Chamber

Postby Andrew Davie » Thu May 23, 2019 12:45 am

I've moved this thread to a more suitable category. You will find it in "Off Topic" from now on.
/moderator
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Re: A Spark Chamber

Postby Viewmaster » Thu May 23, 2019 1:06 am

Andrew Davie wrote:I've moved this thread to a more suitable category. You will find it in "Off Topic" from now on.
/moderator


Thanks.
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Re: A Spark Chamber

Postby Steve Anderson » Thu May 23, 2019 2:25 pm

Viewmaster wrote:Non pulsed HV to start with, as the first spark chambers had this so
this is old fashion stuff. (Pulsing the HV to micro secs is expensive and complicated.]


Agreed, generating short HV pulses isn't that simple a process. In a radar system the HV pulses for the magnetron are generated by using the properties of saturating inductors/transformers.

A capacitor is first charged to a few hundred volts, then via a fast switch (tube or semiconductor) applied to the primary of a toroidal transformer with the appropriate turns ration required. At first the output used to drive the magnetron produces a nice square wave output - then the transformer saturates (deliberately) and the output pulse ends as quickly as it started.

Selecting the correct sized core, turns ratio and magnetic properties of the core gives you control over the output pulse duration. This field is a bit of a 'black art', I used to be able to design these things, but that was some 40 years ago and over time I've lost it (many other things too).

The output pulses where able to drive magnetrons to a peak power of 100kW, but the pulse was nano or microseconds in length with a lot of time between them for the return signals to arrive, so the average power wasn't that much more than the average microwave oven - which also uses a magnetron.

Steve A.

As a footnote, keep all magnetic media away from microwave ovens if you're pulling one apart (hard drives and the like). The magnetron has an intense magnetic field, most of it is directed toward the resonant chamber, but even the magnetic leakage is enough to wipe a hard drive.
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