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Harald,

It would have helped if you included a picture or a link to the detector you were considering. A quick eBay search turned up a Rigaku scintillator detector such as this <https://www.ebay.com/itm/153324151509>. Is this similar to what you were considering? I’ve included a couple images below because the eBay link will expire. This appears to be a scintillator detector and not an x-ray tube.

The first question you should answer is what is your intended use of a "scintillator" detector? Knowing what you are trying to measure would allow others to offer opinions on the appropriateness of a particular detector. I’d hazard a guess this is a small NaI(Tl) detector with a beryllium window coupled to a photomultiplier tube used to capture low energy photons (based on the images and its intended use). If you’re planning on doing elemental analysis by x-ray fluorescence this might be just the detector to get you started. Not knowing the exact material, size, or any specs of the detector makes it a fishing expedition. The fact Rigaku makes XRD and XRF equipment suggests their detectors will be optimized for low energy photons. Purchasing it and tearing it apart will remove the mystery.

Taking a random part off a system and trying to reverse engineer it can be an easy or a monumental task. Having little experience with the design and operation of the particular part puts it more on the difficult side. If you have a good familiarity with photomultiplier tubes and preamps then reverse engineering this particular part might not be all that difficult.

Bruce

As I posted previously, and found from the article you provided, it stated that some units used a simple scintillation detector. Other units, I have to assume, then used visible light detectors - either single element or maybe multiple elements (likely silicone diode array(s) found in cameras) that were used to detect the visible light created by fluorescence from the x-rays hitting the IP or PET films in the spectrometers. If the company cannot or does not provide information on the unit you have, providing a picture is, as Bruce suggests, a good idea to help people here determine the detector type.

Ok. Here come the pictures (assembled from two independent ebay offers of the same article):


Desired inention/ purpose of the detector:

Harald_Consul wrote: Beryllium window detection tubes like the Rigaku tube are perfect broad band particle dectors (alpha, beta, gamma radiation and protons, I guess). It would be perfect to optimize the design of an ion gun.

[edit]
It would also be helpful, if you described how to figure out the electrical wiring of the plugs of your scintillation tube using low voltage from a multimeter or so, assuming the case you have lost the manual.
[/edit]

I have decided on the successor Rigaku detector tube model 211080W now, which Bruce had figured out.

I first thought, it would be too expensive for me, but the seller gave me 33% discount. 400 USD for such a detector tube is a very good deal.

I will power it with the BERTAN PMT-20C/N-1 OPTION 1; 0 to 2KV HIGH VOLTAGE POWER SUPPLY. This guy also gave me 25% discount.

Just still need to know about the wiring of of the sensor connector, which has one pin more than the M8 4-pin sensor connector.

Harald,

I’ll be following your efforts with much interest. I would imagine you’ll have to do a complete teardown to really understand what you have purchased. There is no way of knowing the signals on the connectors unless you reverse engineer the electronics inside (or get a schematic from Rigaku). If this is truly an NaI(Tl) detector you’ll want to know the size and the condition of the crystal. They are hydroscopic and can crack if mishandled. If you purchased this as “used" on eBay you should be able to return it if the crystal is damaged.

As for the intended use I don’t think these would be useful for optimizing an ion source. I do not believe protons of low energy will penetrate the window material (you'll need the thickness and stopping power tables to confirm). The maximum counting rates for NaI detectors are on the order 1e6 counts/second which would correspond to a tiny ion current. I would also think hitting a detector with an ion beam of much power would quickly destroy the window.

It could be very useful for general counting and maybe even some spectroscopy work depending on the crystal size.

Good luck!

Bruce

Oooh f***, I didn't consider the scintillator crystal is hygroscopic!! In Germany most incoming parcels get desinfected with some glue liquid as a biological warfear counter measure (German Angst, you know). I really hope this won't damage the crystal.

From my (unaware) point of view there basically may be the follwing approaches to measure the power of a ion beam by a scintillator:

1. Using a scintillator for alpha radiation [with Cesium iodide (CsI) or zinc sulfide (ZnS) crystal]
2. Using a dummy target, that will produce gamma radiation, when bombarded with ions, and measuring with a scintillator for gamma radiation
3. As no. 2, but slowing down the gamma radiation with lead or sonmething to x-ray radiation and then measuring with a scintillator for x-ray
4. Reversing the polarity of the ion gun and producing an electron beam instead (for optimizing the design, only), beaming it onto a dummy alu-foil (tin-foil) target producing x-ray bremsstrahlung, then measuring with a scintillator for x-ray

No 4. is what I have got currently on my mind (until you tell me better ).

Harald
We use beam profile monitors at work to know the shape and position of our ion beams
look them up they are a bent peice of wire that rotates within the ion beam tube and present a differing position target to the beam without taking out much beam energy so you can leave them in while running
I tried to attach a PDF but the new rules are inane
lookup tupb005.pdf

I believe an NaI scintillator is the wrong device for optimizing a low energy ion beam. IMO, the very first step would be measuring the beam current with a faraday cup and an electrometer. Alpha’s from #1 will not make it through your window (edit: I assume you mean helium ions from an ion source not alpha particles from a nuclear decay). What x-rays can be produced from a few keV ion beam in any material and with what yield? I claim #3 would produce no usable x-rays based on the answer to #2.

John and Andrew have done extensive work with ion sources so take note of their suggestions.

Bruce

Read both of Bruce Meagher's posts carefully. He is 100% correct.

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.)

Harald,

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.

That's been very helpful Michael. Thanks.

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:

• The debris on the high voltage BNC plug might lead to the polarity of the high voltage.
• Pre-amplified scintillation tubes are often powered with positive high voltage and positive supply voltage for pre-amplification [compare page 3 (page count as labeled) of the linked PDF], as PNP and NPN transistors do not switch with the same speed. This might lead to the polarity of the supply voltage of the preamplifer board (delivered through the 5 pole cable).

Some further thoughts from me:

• The external 5 pole connection of the preamplifer board fits to the preamplified positive going signal scheme in https://www.crystals.saint-gobain.com/s ... _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?