X-Ray experimentation platform - The Tel-X-Ometer - Fraser's been buying again !

[Fraser]

The Tel-X-Ometer 580

As some forum members are aware, I am a qualified user of X-Ray generating and imaging equipment. As such I am always on the look-out for X-Ray related equipment such as generators and X-Ray radiation measuring equipment.

This thread details a recent purchase of mine. I was aware of its existence but the ones that I have seen for sale have been crazy expensive. The unit is still in production and may be purchased from the OEM, TEL-Atomic, new for $12K or used for $4K 

http://www.telatomic.com/x-ray/

The Tel-X-Ometer is really designed for education and experimentation using X-Ray in a controlled and safe environment. The unit is intrinsically safe to permit its use in educational establishments such as schools and universities.

I bought my unit from an IT recycler with whom I often do business. It was an open ebay auction but I was the only bidder. Some people are put off buying such equipment as they see the Radiation Trefoil and do not have the test equipment to ensure that it is not leaking X-Ray. The unit cost me the grand sum of £50 ($75) and that ended up including postage as well  The unit arrived this morning and happily its fragile looking dome survived the journey. From the stickers that were applied to its case I could see that it was Ex. Kingston University and it looks to be in very good condition. Just a broken plastic bracket that holds the moving stage adjusting mechanism. An easy fix.

So what is the Tel-X-Ometer 580 ?

Tel-Atomic say:

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The Tel-X-Ometer is a spectrometer which can easily be adapted to become:

A Broad Beam of X-rays for analysis of the General Properties of X-rays.
A Single Bragg Diffractometer having a scale accuracy of 5 minutes of arc.
A Powder Camera for Debye/Scherrer experiments to an accuracy of 30 minutes of arc.
A fluorescent Radiation Emitter for a study of the Moseley Theory that every element is characterized by its Atomic Number.
An Experimental region for the mounting of innovative studies

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The unit is basically a custom small spot X-Ray tube mounted within a lead glass dome shield and projecting a shaped beam of X-Ray energy across an experimentation platform. On the platform there is a moving stage that provides a mounting point for test samples, crystals and X-Ray detection sensors. The stage uses commonly available 35mm slide mounts which is great as I managed to buy a load very cheaply this week.

The X-Ray beam is shaped such that it is the diameter of the Trefoil when it hits the front metal ID plate. On the rear of the ID plate, 1mm of lead attenuates the X-Ray energy to a very safe level for educational use without the need for personal dosimeters. The confinement of the beam may be increased using push in adapters that mount on the X-Ray Tube's output port. These adapters have either a smaller hole diameter to reduce beam-width , or a thin slot to create a curtain of X-Ray energy. The plastic used for the dome contains high levels of Chlorine and acts as a safety shield from reflected X-Ray energy. There are several safety interlocks to prevent X-Ray generation without all the safety features in place.

A timer is mounted on the front panel that ensures that the unit cannot be accidentally left running for long periods of time. The timer provides operation for up to 1 hour before it switches the unit off. The X-Ray tube current may be both monitored and adjusted using ports on the front panel. The current monitoring just needs a meter capable of displaying up to 100uA. The 580 unit is set at 80uA tube current but the OEM recommends that this is lowered for some experiments to prevent sensor saturation when using very sensitive X-Ray detection equipment.

Power for the X-Ray tube comes from the built in step up power supply. The unit runs on AC Mains and contains an inverter that drives a step up transformer similar to the principle used in CRT Televisions. The HT output of the step up transformer is fed to a voltage multiplier. The resultant EHT is then supplied to the X-Ray tube. There are two voltages available on the unit, 20kVp and 30kVp. These voltages are in the soft to hard X-Ray region and so useful for all manner of experiments and X-Ray imaging.

The X-Ray tube is a custom made item for Tel-Atomic. It costs $2000 for a spare ! The X-Ray tube is of conventional design and this is what Tel-atomic has to say about it:

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TEL 2581 MINIATURE X-RAY TUBE
This is a hard vacuum, hot cathode X-ray tube designed for the Tel-X-Ometer. It has a copper target anode.
A thin concave bubble window of 0.25mm thickness is hand blown into the borosilicate glass envelope to transmit a high proportion of the characteristic radiation without recourse to other more expensive window techniques.
The cathode is a helical filament made of tungsten wire and the cathode/anode geometry provides a very small focal point.

Continuous rating: 30kV, 80 µA
Heater supply: 4V 1A
Dimensions: 100mm long, 32mm diameter
Mounting: B13G type

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The fact that the tube is designed to produce a very small focal point is advantageous as it provides better X-Ray imaging capabilities.


The available accessories for the 580 are detailed here:

http://www.telatomic.com/x-ray/accessories.html

All appear to be expensive, but that is lab equipment for education for you.

My unit was understandably sold as untested and for £50 I was not at all concerned with the risk that the power supply or X-Ray tube could be dead. When the unit arrived I gave it a quick inspection and immediately found that it was not in working order. The ‘fault’ was nothing more serious than a wiring failure in the mains plug ! The live wire had been pulled out of the fuse carrier. Re-terminating the mains cable solved this little issue and the unit was ready for a power-on test.

I held my breath as I switched the 580’s power switch to the ON position and adjusted the timer to 5 minutes……… I breathed a sigh of relief when I saw the X-Ray tubes filament glowing happily beneath the Anode. The EHT was set to 20kVp in order to give the tube some conditioning. The X-Ray button was pressed and ………. She fired up without incident. X-Rays were produced and all appears to be well. After some conditioning, I increased the EHT to 30kVp and tested the unit again. All was well with no smells of burning or other nasty surprises from the power supply. She’s a good-un 

The user manual for the Tel-X-Ometer is available for free download from several on line sources. Tel-Atomic offers a pretty rough PDF copy that does not contain the schematic diagram of the unit. I found another source that has a better copy and also includes the full schematic diagram ? Sadly the manuals are too large to attach here.

http://www.telatomic.com/x-ray/docs/TEL-X-Ometer_Manual.pdf

Better copy with schematic

http://uwf.edu/awade1/ModernLab/Manuals/Tel-x-ometer/TELETRONX-RAY.pdf

I attach some external pictures of the Tel-X-Ometer and will add internal pictures as soon as I have the time to open her up for internal inspection.

What am I going to do with her ? Well I have the Rolls Royce of X-Ray imaging units in my Faxitron MX-20 so I really have little need for another imaging unit….but the Tel-X-Ometer enables me to safely experiment with a 30kVp X-Ray source for investigating and constructing X-Ray detectors, energy measurement sensors and the effects of different materials on X-Ray energy penetration. The unit is designed to have materials samples placed in 35mm slide frames and these are then inserted into the slots of the test stage. The X-Ray measurement sensor is then placed behind the test piece to measure transmission etc. I will also be testing various CCTV camera based X-Ray imaging techniques that use a Scintillator screen in front of a conventional high sensitivity miniature monochrome CCTV camera. The unit is also designed for X-Ray crystallography and XRF activities.

I think I shall learn much more about X-Ray’s whilst experimenting with this fine piece of test and experimentation equipment. It will certainly be a lot safer than running a conventional Dental X-Ray head in an open site scenario for experiments.

Fraser

[Fraser]

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[Fraser]

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[Vgkid]

That is actually pretty cool, I was reading through their website.

[Fraser]

The Tel-X-Ometer has been around in virtually unchanged format since the mid 70's. It is a classic case of 'if it ain't broke, don't fix it' 

It does look a bit weird and dated but its operating principles are sound and it appears to be a very much respected experimentation platform for those learning about X-Ray energy, Crystallography and XRF.

Time will tell how much I use it, but I could not resist buying it 

Fraser

[TheSteve]

Great score!(Doesn't it make you thankful not everyone is technical)

Thanks for posting the pics and the operational details.

[nfmax]

Oh wow! I used one of these, or one very like it, back in 1973 or 1974, when I was studying for physics A level. Our teacher was a Wawick University PhD and a small group of us went over with him one weekend to make an X-ray diffraction experiment in the undergraduate teaching lab.

It seems my past is catching up with me this week - we had a 40th Anniversary student house re-union over the weekend. Amazing how little people seem to have changed.

[XynxNet]

It is a nice little unit. Unfortunately we are no longer allowed to use our unit in germany, when pupils or students are present, because it fails new safety regulations.

[Fraser]

@ XynxNet,

I can't say that I am surprised really. The unit has changed little over the 40 years that it has been made. They added a key operated on/off switch to newer models so that may have been to meet new regulations. The 'safe' surface radiation level may also have changed over the years.

When I first saw these units, I thought 'no way' could it be safe with a 30kVp X-Ray tube operating behind just a plastic dome. It was when I read the details of the lead glass tube dome, carefully shaped beam, lead beam shield and Chlorine filled plastic dome lid that I saw how they had made it safe. I personally prefer metal shielding around X-Ray chambers but having used a Lixiscope I know that safety may be achieved through careful beam shaping and relatively little containment.

For those unaware,the Lixiscope X-Ray inspection tool uses a Radioactive Iodine Isotope (I 125) that emits radiation from a carefully designed port that shapes the beam so that it is contained within the area of a protective shield at the users end of the instrument. The user views objects placed within the emitted beam via a scintillation screen and image intensifier. I used these but always wore appropriate X-Ray protective clothing due to the open source nature of the instrument and the issue of reflections etc. Users also needed to be registered for Dosimeter badges and monitored regularly. The Lixiscope was originally designed for Paramedic use where imaging of broken bones was needed.

Fraser

[Fraser]

I have tracked down the latest version of the Tel-Atomic user manual.

It may be found here:

http://www.telatomic.com/x-ray/docs/TEL-X-Ometer_Manual_V1.0.1.pdf

Fraser

[Fraser]

I gave the Tel-X-Ometer  a service today.

It was in full working order but I thought it would benefit from a gentle clean and lubrication of the moving parts.

In order to do this work I had to dismantle the unit so you can now see what lives inside 

The full schematic is to be found in the manual, referenced earlier in this thread.

To open the unit I only had to remove a few screws around the top section of the unit. The whole top deck and associated electronics may then be lifted out of the mostly empty base 'tub'.

The key parts that become visible are the PCB, mains transformer, two large heatsinks, HT transformer and associated HT tripler. The EHT drive for the X-Ray tube passes up through the deck and onto the top of the tube.

I discovered that the HT and EHT cables had attracted black dirt and this was removed with IPA. It is important to keep all parts that work at high voltages clean in order to avoid flash overs or high voltage leakage. In general the unit was very clean inside.

There is no fan cooling in the unit which did come as something of a surprise as the convective cooling is not that efficient due to the design of the case.

The HT transformer is similar in design to that of a CRT television LOPT. The output of the HT transformer is 6.7kV or 10kV depending on the position of the EHT selector switch. This is passed to a standard CRT television diode tripler module. The unused focus output wire etc have just been cut off and insulated with resin.

I removed the lead glass dome and the X-Ray tube for cleaning. I managed to get some better pictures of both. The X-Ray tube is a very dinky little unit and appears to be in good condition. There is visible discolouration of the glass caused by its exposure to the X-Rays emitted from the angled copper anode. This is quite normal and does not indicate that the tube is nearing the end of its life. Look carefully at the pictures of the tube when placed on white paper. The glass is shaded slightly brown around the copper anode

The Tel-X-Ometer was reassembled and tested. I completed a full Radiation survey on it using a MiniMonitor 900 with a type D probe. The unit is very well behaved and no leakage of any significance could be found. With the base removed I noted that there was around 100 uSieverts/hour of X-Ray energy coming out of the bottom of the tube, but this is contained in the base 'tub' when the unit is fully assembled.

Pictures follow........

[Fraser]

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[Fraser]

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[Fraser]

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[Fraser]

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[Fraser]

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[SeanB]

Those shadows in the glass are nice and sharp, nicely cut off by the edges of the electrodes.

[Fraser]

It's a very nice little tube. It looks simple but the OEM went to the effort to have it custom made. It certainly isn't a cheap part to buy from them !

I suspect Tel Atomic have quite a mark up on this product and spares though. It's a specialist educational and experimentation tool so I suppose they charge what the market will pay. When you look inside the unit it is very 'old school' and I suspect a new unit would be little different if bought today. The units appear to be pretty much hand built.

As a commentary to readers on X-Ray generation and imaging........

As can be seen, X-Ray generators are not very complicated. The challenge is finding a suitable X-Ray tube, EHT constant current supply and X-Ray radiation containment. All are within the capabilities of the competent DIY builder. The real challenge is how to create an image using the X-Ray beam.

Creating an X-Ray image has always been a challenge for users of X-Ray. The classic media is X-Ray and light sensitive photographic film sat behind a scintillation plate, that also contains filters if needed. Advances in technology created other techniques including the use of special 'memory' plates that are scanned to read the latent image, video and digital cameras viewing a scintillation plate, and lastly, direct digital capture using an active imaging array sitting behind a scintillation plate. My Faxitron MX-20 uses the direct active imaging method. For those unaware, the scintillation plate converts X-Ray radiation into a wavelength of light that may be seen by the imaging detector, be it film or active electronics. X-Ray film can work without a scintillator but requires longer exposures.

The DIY hobbyist can safely experiment with X-Ray imaging using the Tel-X-Ometer. The OEM can supply special X-Ray film packs that also contain the required developer sachet so no dark room is needed. This is similar to the original Polaroid instant film design. Scintillation plates are quite easy to find. They are available from specialist suppliers or may be salvaged from old X-Ray cassettes that are common on eBay cheaply. To image the scintillator output, a Sensitive CCTV camera may be used. A digital camera with long exposure capability may also be used. I have an image intensifier that can amplify the scintillator output to enable faster shutter speeds or lower sensitivity CCTV cameras. Image intensification stages are commonly found in professional electronic imaging systems. There is plenty of scope for experimentation with X-Ray imaging, provided a safe X-Ray generator is employed, such as the Tel-X-Ometer. An alternative would be an X-Ray mail scanner cabinet or the non digital imaging Faxitron MX-20 that sells for around £250 on the secondary market.

Well that's enough from me for now.

Fraser

[pascal_sweden]

With all respect, but I honestly don't understand why a company can produce a toy-like device like this.

How come that they don't put a better protection cover on the top?

Even if the plastic dome is just enough, given that this device costs a fortune, it sounds a stupid approach.

Why not make it more robust. Safety is first priority. And with such a high sales price, they have plenty of money left to make it more robust.

The designers must be so naive! They should forbid people to make X-ray based devices that look like toys.

Must have been made by scientists that have lived on an desolated island for years and who have lost all connection with reality.

Not only the people who built the device can be questioned, but also the people who use it, and who don't even see it as a problem the way it is built.

Why do you want to play with X-ray in the first place? Stay away from things that you don't understand!

[Fraser]

Huh?

The very first line of this Thread tells you all you need to know.

I am a qualified user of X-Ray and have used such for over 2 decades. I know exactly what I am doing and the hazards associated with X-Ray Radiation exposure. I have no desire to cause myself cell damage.

Your post appears a tad OTT IMHO.

Firstly, the Tel-X-Ometer 580 has been in existance since the mid 1970's and is still available to buy. It is licenced for use in the UK by competent persons as a demonstration and experimentation tool.

The clear dome is deliberate as it enables reading of the various angle graduations. The instrument was apparently designed and built to be intrinsically safe and robust as a hard life was expected by the manufacturer. They say such in the manual. The unit has several micro switch interlocks that prevent use without the required radiation screens in place.

I agree that the unit does look odd..... It's from the 1970's remember. A toy though? Whatever gave you that impression ? It has an X-Ray tube that may be driven at 30kvp with 80uA current flow. To attenuate such a low energy X-Ray beam that will be less than 30kev does not need masses of lead or thick metal. It produces soft to hardish X-Ray that is stopped by less than 0.16mm of lead, or a piece of steel less than 1mm thick. As you will have seen from my earlier post, the X-Ray beam is heavily collimated and aimed at a lead attenuator. The tube is surrounded in thick leaded glass, and the thick and robust plastic dome is heavily chlorinated for use as an attenuator. Safety interlocks prevent X-Ray production if the plastic lid is open, the lead glass dome is not in place or the timer is not set.

Now where exactly do you believe this apparatus to be unsafe ?

Remember, life is full of dangers if you want to win a Darwin Award badly enough. At $12K it isn't within the pocket money buying capability of most children.

If you were to suggest that it should not have been sold on the secondary market without the buyer declaring knowledge of safe usage..... I would heartily agree with you. To suggest that the unit is dangerous in any way when used as intended is an over reaction however.

As you will have seen in a previous post in this thread, I carried out a full X-Ray leakage safety survey on the Tel-X-Ometer. It passed with ease. This survey is important when buying used equipment that may have unknown faults or issues. That is just part of being a competent user.

Take a look in a school Chemistry lab some time, there are many very poisonous chemicals used by students that can cause very severe injury if ingested.  It's all about common sense and being qualified to use an X-Ray generator, which I am. Should someone who is not competent to use an X-Ray generator buy one? ..... Common sense says no. This is true in many areas of life, including the driving of a motor vehicle.

Take a look at my Faxitron MX-20 high resolution X-Ray imager threads sometime.

Fraser

[Fraser]

For anyone else wanting to know what I use X-Ray for, here are some X-Ray related threads that I have started or participated in.

https://www.eevblog.com/forum/testgear/x-ray-machines-technology-and-use-in-hobby-electronics/

https://www.eevblog.com/forum/projects/the-x-ray-image-thread-by-aurora-various-electronics-via-x-ray-imaging/msg748531/#msg748531

https://www.eevblog.com/forum/reviews/faxitron-mx-20-x-ray-system-teardown/msg585230/#msg585230

Fraser

[XynxNet]

pascal_sweden, from todays point of view you are right. But this machine is an old design.
 
As far as safety is concerned, this machine is quite safe, for its intended use. But safety regulations change. Especially the safety margin gets extendes. In this case this is actually a good think, because it is an educational device, which unfortunately means it sometimes gets handled by not as competent users as one might wish.

Looking at this machine from an educational point of view the design is quite good. It is very robust, it is easy to use and easy to understand and is has exceptional visibillity.

Of course it doesn't have any of the nice features of todays sensor and digital technologies.

Pricing is due to the traps of the educational market. (Few suppliers, small quantities, conservative institutions, etc.)

A modern full features x-ray-machine, purpose build for the educational market with all extras (including ct-scanning unit) costs about 30000€, by the way. I kid you not. I got the advertisement a few month back and wondered how many schools can pay that kind of money.

For the money of a new tel-x-ometer you can also get today a basic computerized x-ray-machine on the educational market. "basic" means a motorised goniometer for the detection tube, a detection tube, a computer-interface for basic parameters like timer, voltage, current and the detector, phosphor-screen.

All the nice extras like an energy detector, digital imagine units, ct-capability costs extra... a lot extra.

[evgeek]

thanks for the tips. i just purchased an used tel-x-ometer from ebay. it didn't come with any accessories. I am new to x-rays. I want to use this for some simple x-ray experiments. i am looking for g-m tube and some basic accessories for tel-x-ometer. any recommended g-m tubes that would work with the tel-x-ometer?

[Fraser]

Hi EVGeek and welcome to the forum 

Before using the Tel-X-Ometer you should really have it checked for X-Ray leakage to ensure that all is well with it.

That comment aside, these units are actually pretty safe if used correctly and with common sense. If you are new to X-Ray energy and its effects on living tissues it would be worth your time to do some reading about Soft X-Ray's.You will then better understand the safe use of such and the limitations of these X-Ray's with respect to the penetration of materials.

The Tel-X-Ometer has two levels of HV that are applied to the X-Ray tube, 20KVp and 30KVp. Both will produce pretty soft X-Rays but on the 30KVp setting you get closer to Hard X-Ray, so materials penetration is better. Note that KVp is not the same as KeV. 30KVp will not produce 30KeV at the X-Ray Tube output port.

When you test your unit, listen carefully for any sounds of arcing as the HV generator can arc over on its output lead due to close proximity to the metal chassis. If you hear any arcing, sort it out as it degrades performance and can lead to HT multiplier failure.

Accessories for these units are expensive as they are being sold into the educational sector, so mark-up is high. The slotted moving bridge takes normal 35mm transparency photograph frames as used in photographic projectors. You can make most accessories yourself. Slit plates are just lead foil with a thin slit cut in it. X-Ray tube aperture slits and pin holes are lead foil in a plastic 'top hat' that inserts into the X-Ray rube output port. Just cut a suitable slot or drill a pin hole for the desired effect. The fluorescent crystals are sometimes available on ebay but take some finding. They are called scintillation crystals and are used in some radiation monitor heads that incorporate a scintillation crystal and photon-multiplier tube.

With regard to a G.M. tube that will operate well at the Tel-X-Ometer X-Ray energy levels, you need to find an ALPHA radiation sensitive tube that has a MICA window. The Mica window permits easy entry of the low energy X-Ray beam into the counting tube. Metal tubes without a Mica window will tend to attenuate the X-Ray beam as low energy X-Ray is attenuated easily by metal, including Aluminium. Such a tube may still give some indication however, so you could try the cheap Russian tubes that are an aluminium cylinder with the connections at each end. The flat Pancake type G.M tubes will work but are often too large for your application. The tube you need will be around 15mm diameter by 40mm in length with  Mica window at one end and a anode connection at the other.

If using a G.M tube, please ensure that a suitable anode current limiting resistor is in place. Failure to use such will lead to fast destruction of the G.M. tube.

That is enough from me for now but if you Google Tel-X-Ometer you should find the original experiment books and instructions for the unit. Accessories are also detailed on line for you to clone if required. I recommend that you build a X-Ray tube current meter that was sold as an accessory. It lets you set tube currents accurately up to the maximum 80uA. Sometimes you will want to decrease that current, especially when working with a G.M tube. You just need a moving coil 100uA FSD (or greater) meter and a 3.5mm plug for the current monitoring port on the front of the unit. Nice and simple to make but very useful. I managed to buy a nice cased Bench type 150uA FSD moving coil meter that was made for schools and it is perfect for the task. I only had to make a simple lead to connect it to the Tel-X-Ometer.

Fraser

P.S. sorry I did not reply to your message...I have been buried in other work lately.

[evgeek]

Hi Fraser,
thanks a lot. this is great info for me to get going. i really appreciate your help. i have been reading all yours x-ray related posts. really awesome. thanks.