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Re: How to figure out the specs of old Rigaku scintillation tube probe?

Posted: Tue Jan 15, 2019 7:47 pm
by Harald_Consul
Unfortunately - as I told before - I've already purchased the x-ray scintillitor tube. Mainly because of two reasons:
  • I have got a small budget, thus I am dependent on maximum-universal measuring insruments.
  • All those 50kV warning postings jared on my nerves.

By the way, where have all those 50kV warning postings gone? (Cleared by moderation without leaving back a trace? I am not offending against the way of moderation. It's just been surprising to see postings disappear without any trace. I am just used to, the cleaning moderation would leave back an empty posting. The mod is free to delete this text within these brackets, if desired.)

Re: How to figure out the specs of old Rigaku scintillation tube probe?

Posted: Wed Jan 16, 2019 3:49 am
by Michael Bretti

I would strongly suggest you research more into the fundamentals of beam systems, beam optics, and beam instrumentation to save yourself a lot of frustration and money pursuing methods that will not yield results you are looking for. While you can reverse the polarity of a gun and use it as an electron beam source (with some modifications), electron and ion beams behave differently under the same conditions, there is no way you could optimize your ion beam output by looking at an electron beam from the same device. They are just not equivalent. X-ray yields can also be very different based on even just target material, so looking at just x-ray output alone will not be necessarily useful for optimizing a beam. A beam can of course be optimized for x-ray output, but that does not mean it is optimized in all aspects.

You also wouldn't need to look at the x-rays at all either - as mentioned in other responses, a simple Faraday cup is incredibly valuable and powerful, and will yield current readings, for both ion and electron beams. At this level, your beam accelerating voltage and current is also very low overall, so you wouldn't be producing anything much of use from beam-target interactions besides neutrons if running a deuterium beam into a self-loading target with high enough voltage/current. If you are measuring the voltage input into your gun, and you know the beam current on a Faraday cup, that will give you a lot of information to start with.

Also as mentioned, you can use methods such as wire scanners for beam profiling measurements. Ion beam profiling can also be measured using direct scintillation screens with a properly positioned camera as well. If you want to get into more in-depth and complex optimization, stuff like pepperpots with scintillation screens can be used for measuring emittance of the beam. A retarding field energy analyzer or an energy analyzer magnet can be used for measuring the energy distribution of the beam. Time-of-Flight methods can also be used for beam energy as well. There are of course a huge range of diagnostics that can be pursued depending on what you are trying to measure. However, besides a simple Faraday cup, or a direct scintillation screen, other methods become much more complex and involved to implement, especially on a budget.

Re: How to figure out the specs of old Rigaku scintillation tube probe?

Posted: Wed Jan 16, 2019 1:17 pm
by Harald_Consul
That's been very helpful Michael. Thanks.

Re: How to figure out the specs of old Rigaku scintillation tube probe?

Posted: Sat Feb 02, 2019 2:53 pm
by Harald_Consul
Ok guys. Here comes the next episode of how figure out (hack) the signal of the Rigaku scintillation tube probe.

First of all, this is NOT a standard "universitary" scintillation probe, where the original photo multiplier signal goes directly on the signal cable. This is a scintillation probe with an integrated pre-amplifier inside!! (Which is the type of scintillation probe type you want, to process a raw signal in some kind of hacking approach.)


On left side you see the voltage divider. On the right side you the little preamplifer board.

Let's have a closer look at the out pins of the preamplifer board, now.


To keep it simple and stupid, I am simply labeling the external pins of the preamplifier board from left to right as
  • A: light blue
  • B: orange
  • C: white
  • C: dark blue + thin black
  • E: another black connected to the ground of the high voltage cable
The original signal from photo multiplier tube is another (sixth) pin F not visible in the photo.

Third, let's have a closer look on the 5 pole cable, now.


The cable contains
  • light blue
  • orange
  • thick black, which contains white + dark blue inside
  • thin black (which is unvisible in the opposite perspective)
The big red cable is the high voltage cable, which is connected to the BNC plug.

Last for completeness only, a look at the 5-pin connector again (which already has been posted before)


On the left you see the high voltage BNC plug. On the right you see the - much more interesting - the 5-pin connector, which is the end of the 5 pole cable in the previous photo.

Happy guessing on which cable has which electrical assignment now.

Some thoughts from me:

Re: How to figure out the specs of old Rigaku scintillation tube probe?

Posted: Sun Feb 03, 2019 12:24 pm
by Harald_Consul
Some further thoughts from me:
  • The external 5 pole connection of the preamplifer board fits to the preamplified positive going signal scheme in ... _70421.pdf page 3 and 4 (page count as labeled)
  • Concluding from this the five poles would be
    • -24 V OR +24 V FET bias voltage (I cannot figure out from the manual: sometime they speak from -24 V and sometime they speak from +24 V)
    • +12 V operating voltage
    • -12 V operating voltage
    • Ground
    • Signal Out
  • Maybe the preamplifier does work like one of the three FET biasing circuits metioned in the Circuits today FET biasing article? How can I check this?