Model Diesel: 32mm bore, 38mm stroke, indirect injection

[Roger B]

That's very cool. Working as a structural biologist I've sent samples to the Australian Synchrontron but never had a chance to visit in person.

And those are some monster electron beams you work with! I've done a lot of electron microscopy, but the instruments I've used were 200 or 300 kV. 3MV electrons would be something else... I guess you are going for deep penetration into the material when crosslinking? Just to nerd out a bit, what do you use for the electron source? Instruments I worked with used tungsten or LaB6 hot cathodes but the fancy cryo-EM microscopes at my uni use cold FEG sources, makes the beam more focused.

A 3 MeV electron will penetrate around 10mm of polyethylene, less in higher density materials.

The electron source is a spiral of tungsten wire about 1 cm in diameter, there is a picture of one in the white paper. As the beam is 10s of kilowatts we don’t want it too tightly focused. If it goes astray things melt quite quickly.

 

[Roger B]

Wow!
That is some technology.
In 1976 I worked for a cable maker, and we obtained the early samples of Cross-linked polyethylene insulated wires. It was my job to test them in the lab to all the tests normally used to confirm PVC, elastomer and polymer cables, so we (in the factory) could appreciate the advantages of this "new" material. All I knew then was a simple comment. "It is PE electrically, but should be almost as tough as an elastomer, unlike PVC insulation."
In one test - the 30 second flammability test - it certainly was not like other materials, as the PE naturally had NO resistance to flames. Just like applying a Bunsen flame to a wax candle, it melted and burned.
But compared to "normal" PE and PVC it was considerably more resistant to abrasion and cutting with a sharp blade. But melting it, as with in-factory welding of thermoplastic insulation, just made it into normal PE... and lost all the advantageous characteristics of cross-linked PE.
I don't remember much about cross-linked PE otherwise...
I never found out how PE was cross-linked either!
K2

This was probably chemically cross linked using the Sioplas process. Pirelli in Southampton was working on the process when I started there in 1977. BICC further developed this to the one step Monosil process. Pirelli and BICC didn’t install electron beam facilities until the early 80s.

 

[Steamchick]

Hi Roger, I was working at BICC Helsby factory back in '76 - in the production test lab., testing products we made. Hence I was given the HDPE cables to evaluate.
I enjoy and appreciate the comment: "As the beam is 10s of kilowatts we don’t want it too tightly focused. If it goes astray things melt quite quickly." - Love it!
Does it give off lots of deadly X-rays when it hits metal? I assume that blasting a PE coated wire with electrons means that some hit molecules of the metal wire and knock-off their electrons, thus emitting energy when they return to their normal orbits? Or is it neutron disturbance that causes X-rays? - I really haven't a clue, just find learning about this very interesting..
I did work with a guy who was instrumental in installing a heavy duty laser for welding steel panels together.... He described the job as making a truly light-tight box around a sword of light, where reflected laser light escaping could create a fire hazard hundreds of metres away, if only a pin-hole of the beam escaped. Not conducive to living next to it! In power terms it would be like a welding torch but 10 times hotter and more powerful - if it touched flesh - or so he explained...
I have no idea what an electron beam of that power could do to someone.
And to think that we, the masses, sat in front of Cathode Ray tubes (the TV) for hours every day for many decades, protected only by a bit of lead glass from the X-rays...
K2

 

[ShopShoe]

Steamchick,

There was a worse situation with TV sets in the late 1960s. A manufacturing problem was found to be involved in the production of high voltage regulator tubes in the power supplies for the CRTs which resulted in those tubes providing another beam out of the set toward the viewer, as well as additional radiation from the CRT as the voltage went way above normal level. I was in high school at the time and working for a service technician and saw the tubes with the crooked elements that were removed and replaced.

--ShopShoe

 

[Richard Hed]

Steamchick,

There was a worse situation with TV sets in the late 1960s. A manufacturing problem was found to be involved in the production of high voltage regulator tubes in the power supplies for the CRTs which resulted in those tubes providing another beam out of the set toward the viewer, as well as additional radiation from the CRT as the voltage went way above normal level. I was in high school at the time and working for a service technician and saw the tubes with the crooked elements that were removed and replaced.

--ShopShoe

Whoa?! Tell us more. I never heard that before. Most electrons, even when moving at a fast rate don't travel very far but even so, it's a bell shaped curve, some travel further. Maybe that's why my children came out with three heads and 2-1/2 arms?! Can I still sue the tv companies? Seriously, that is very interesting. I bet the manufacturers kept THAT quiet. If you know anything more about it, I would certainly be interested to know more.

 

[ShopShoe]

Some searching turned up this summary:

https://www.rfcafe.com/references/r...tv-x-rays-radio-electronics-november-1968.htm

Note the insane/crazy voltages involved (compared to today).

This article from TIME magazine also came to light:

https://time.com/archive/6631036/electronics-x-rays-in-the-living-room/

I remember an article from back in the day which included a picture or diagram of a misaligned tube, but I was unable to locate it.

Anyway, I ended up getting lost in the links that came to light about the debate the surrounded the whole issue. It seems that we were just as paranoid about just as many things as we are now, just not the same things.

--ShopShoe

 

[Richard Hed]

Some searching turned up this summary:

https://www.rfcafe.com/references/r...tv-x-rays-radio-electronics-november-1968.htm

Note the insane/crazy voltages involved (compared to today).

This article from TIME magazine also came to light:

https://time.com/archive/6631036/electronics-x-rays-in-the-living-room/

I remember an article from back in the day which included a picture or diagram of a misaligned tube, but I was unable to locate it.

Anyway, I ended up getting lost in the links that came to light about the debate the surrounded the whole issue. It seems that we were just as paranoid about just as many things as we are now, just not the same things.

--ShopShoe

Whoa! I could be damaged! Thanx for those articles.

 

[Steamchick]

Thanks Shop Shoe.
Interesting, but I think only affecting the USA?
Unlike Web Cams that see and record everything... within view..?Globally!
K2

 

[Roger B]

Hi Roger, I was working at BICC Helsby factory back in '76 - in the production test lab., testing products we made. Hence I was given the HDPE cables to evaluate.
I enjoy and appreciate the comment: "As the beam is 10s of kilowatts we don’t want it too tightly focused. If it goes astray things melt quite quickly." - Love it!
Does it give off lots of deadly X-rays when it hits metal? I assume that blasting a PE coated wire with electrons means that some hit molecules of the metal wire and knock-off their electrons, thus emitting energy when they return to their normal orbits? Or is it neutron disturbance that causes X-rays? - I really haven't a clue, just find learning about this very interesting..
I did work with a guy who was instrumental in installing a heavy duty laser for welding steel panels together.... He described the job as making a truly light-tight box around a sword of light, where reflected laser light escaping could create a fire hazard hundreds of metres away, if only a pin-hole of the beam escaped. Not conducive to living next to it! In power terms it would be like a welding torch but 10 times hotter and more powerful - if it touched flesh - or so he explained...
I have no idea what an electron beam of that power could do to someone.
And to think that we, the masses, sat in front of Cathode Ray tubes (the TV) for hours every day for many decades, protected only by a bit of lead glass from the X-rays...
K2

The electrons cause X Rays to be emitted when they are stopped, Bremsstrahlung. Higher atomic number materials give off more X rays. Our 3 MeV systems are installed in concrete bunkers with 2m thick walls. At full power you would receive a lethal dose of X Rays in seconds if you were not already burnt by the scattered electrons.

 

[BaronJ]

Some searching turned up this summary:

https://www.rfcafe.com/references/r...tv-x-rays-radio-electronics-november-1968.htm

Note the insane/crazy voltages involved (compared to today).

This article from TIME magazine also came to light:

https://time.com/archive/6631036/electronics-x-rays-in-the-living-room/

I remember an article from back in the day which included a picture or diagram of a misaligned tube, but I was unable to locate it.

Anyway, I ended up getting lost in the links that came to light about the debate the surrounded the whole issue. It seems that we were just as paranoid about just as many things as we are now, just not the same things.

--ShopShoe

Hi ShopShoe, Guys,

I believe that the really dangerous TV's emitting X rays were the projection ones. A lot of them used 30Kv on the tubes.

 

[Steamchick]

Having had my Prostate Cancer blasted with X-rays - apparently it just leaves a lump of dead scar material that the body can live with - I would not want to be in the room with your 3MeV Mega blaster!
The only thing that concerned me about the X-radiation therapy was the way the Radiotherapists had to be outside the room, with inter-locked doors, and flashing red lights saying "dangerous radiation" while I was lying on the slab being cooked...
But I am Cancer free in that gland now. Just hope minimal damage to the rest of me as the X-rays and Neutrons went through other flesh as well.
Fantastic technology. Almost science fiction stuff of the future!
Now I wonder what the smart phone is doing to me while it is my trouser pocket...
K2

 

[Nerd1000]

Having had my Prostate Cancer blasted with X-rays - apparently it just leaves a lump of dead scar material that the body can live with - I would not want to be in the room with your 3MeV Mega blaster!
The only thing that concerned me about the X-radiation therapy was the way the Radiotherapists had to be outside the room, with inter-locked doors, and flashing red lights saying "dangerous radiation" while I was lying on the slab being cooked...
But I am Cancer free in that gland now. Just hope minimal damage to the rest of me as the X-rays and Neutrons went through other flesh as well.
Fantastic technology. Almost science fiction stuff of the future!
Now I wonder what the smart phone is doing to me while it is my trouser pocket...
K2

The trick with radiation therapy is they spin the beam source around and blast you from lots of different directions, but always aimed through the tumour. So the tumour gets hit with a lot more radiation than the rest of you. And I wouldn't worry about the phone, that's non-ionising radiation.

Anyway, we're miles off topic for the thread. Might be a good idea to open a new one in the right subforum?

 

[Richard Hed]

There's another thing too, the wavelength of the X-ray is no doubt tightly controlled.

 

[Steamchick]

Thanks.
K2

 

[minh-thanh]

I wonder..x ray, high voltage regulator tubes in the power supplies for the CRTs..pvc..PVC, PE processing..what does that have to do with model engines ???
??????????

 

[Roger B]

My fault I'm afraid. I linked a model engine related picture from my Flickr account which also contains picture of industrial particle accelerators and it sort of grew from there.

 

[minh-thanh]

My fault I'm afraid. I linked a model engine related picture from my Flickr account which also contains picture of industrial particle accelerators and it sort of grew from there.

Maybe not or maybe yes, I don't know
Or simply: "it's not related to the topic, PM or create a chat group"

---------------------------------------
---------------------------------------

 

[Steamchick]

Sorry Minh Thanh. I did ask the questions prompting Roger's explanations, with some background of my own, as to why I was interested. Should have been a PM. "One man's meat is another's poison."
I'll try and stay "on track" in future.
K2.

 

[minh-thanh]

Hi K2 !
"One man's meat is another's poison." I don't think so .
Maybe I was a little angry and my words were a little harsh
I'm sorry
Stay "on track" is the best way !