Gold Plated Tungsten Price

Multileaf Collimators to Match Every Shape

Details: Category: Tungsten Information; Published on Tuesday, 02 September 2014 17:46; Written by yewq; Hits: 489

In order to target radiation precisely to the diseased tissue, it is necessary to use multileaf collimators.

First of all, X-ray images are produced to determine the precise position and outline of the tumor. Following this 3-dimensional measurement, an electric motor moves each individual leaf in the collimator to the correct position – with up to 120 leaves being used to shape the outline of the tumor with millimeter accuracy. Then, the tumor is exposed to high energy radiation. During this process, the tumor is radiated by turning the gantry with the multileaf collimator 360° around the patient. To protect the surrounding healthy tissue, a highly precise multileaf collimator is necessary. To protect the environment from unwanted radiation, different shielding parts are widely used.

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High Energy Radiation Shielding

Details: Category: Tungsten Information; Published on Tuesday, 02 September 2014 17:29; Written by yewq; Hits: 494

Applications of tungsten alloy include collimators for the medical industry, shielding blocks, oil well logging tools and instrumentation and nuclear equipment.

Tungsten alloy is an excellent material for use in radiation shielding (high energy photonic). and they are most popularly used for this application. These alloys are excellent materials for shielding and collimation due to their combination of radiographic density, machinability, strength, and low toxicity. Tungsten Heavy Alloy offers a superior protection level to lead in an equivalent thickness and, unlike lead, resists deformation and can be accurately fastened.

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Tungsten: the Perfect Metal for Bullets and Missiles Part Three

Details: Category: Tungsten Information; Published on Tuesday, 02 September 2014 16:25; Written by jwy; Hits: 512

It is used in the spikes in the drive tracks of snowmobiles, the vibrators that wobble our mobile phones when they ring, weights for fishing tackle, the balls of ballpoint pens, and professional darts.

It is also why fraudsters have sometimes managed to make themselves an easy profit by passing off gold plated bars of tungsten as the real thing. And its density and hardness is why the military has called tungsten into service in another kind of evolutionary arms race.

"Tungsten makes very good bullets," the military analyst Robert Kelley tells me. "It is the kind of thing that if you fire it at someone else's armour, it will go right through it and kill it."

And just like the creatures of the Cambrian period, once someone starts using teeth (or tungsten bullets) you need to do something about it.

"If you introduce tungsten into your bullets you've got to introduce tungsten into your armour," says Mr Kelley.

He describes the fascinating balance military engineers have to negotiate between the strength of tungsten and the costs in fuel and manoeuvrability all that extra weight brings.

"They'll put the tungsten on the side of the tank but not on the top. So then people will develop warheads that will fly towards the tank and then at the last minute go up and then drop on it, so then you have to start arming the top of the tank.

"So it is a constant game of give and take."

And tungsten's extraordinary properties have led to the development of a class of missiles that work without explosives.

"Kinetic bombardment" weapons involve firing what are, in effect, spears of tungsten at incredible speed towards your target. They can penetrate thick steel armour and cause terrific, but very localised, devastation.

Tungsten's only rival for this kind of application is the radioactive element uranium. Depleted uranium is (almost) as dense as tungsten and has an added advantage - from a military perspective - that it burns at the extreme temperatures generated as you punch your way through steel tank armour.

That will often blow up any explosives in the tank.

"Put it this way, if you are the guy inside the tank, you will not remember what happened," says Kelley bluntly.

So why does the military still use tungsten if uranium has this macabre, but useful additional property?

Because, as the people of Kuwait discovered after first Gulf War, depleted uranium leaves a potentially deadly dust behind after it burns. It sounds bizarre but, in the world of warfare, tungsten is the eco-friendly alternative.

All these evolving military and industrial uses explain why tungsten is classified as a critical strategic element by many nations.

Yet more than 80% of world supply is controlled by China, and in recent years China has imposed restrictions on the export of tungsten - along with many other raw commodities. It wants to encourage the development of the hi-tech industries that use tungsten within China itself.

That's also helped to push prices up, making previously uneconomic non-Chinese deposits worthwhile to mine.

Hemerdon, on the edge of Dartmoor, is the first new metal mine to be opened in Britain for 40 years, and will exploit the world's third largest tungsten deposit.

It is being re-opened by a company called Wolf Minerals, named after "wolfram", an alternative name for tungsten and why the element is represented by a W in the periodic table. (In fact, "volfram" is the name used in Sweden, where "tungsten" refers to Scheelite, calcium tungstate.)

This new mine is another manifestation of the competitive pressures that shape the modern world and - as we have discovered - drove evolution in the primordial world too.

Though ironically the rocks they'll be mining at Hemerdon are much younger than the Cambrian - a mere 400 million years old.

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Advantages and Applications of Tungsten Heavy Alloy’s Shielding

Details: Category: Tungsten Information; Published on Tuesday, 02 September 2014 17:21; Written by yewq; Hits: 511

Advantages of Tungsten Heavy Alloy’s Shielding：

1.Use not subject to NRC, EPA, or special OSHA regulations;2.High radiation absorption (superior to lead);3.Low toxicity-safer than lead or depleted uranium: simplified life cycle;4.Easily machined into complex geometries;5.Hardness, strength, and ductility make for good durability;6.Good corrosion resistance

Additional Industrial/Commercial/Medical Applications:

Radiography,Nuclear power plant shielding,nuclear medicine,clinical point shielding,X-ray collimators and area shielding,Isotope production, transport, and containment,oncology Isotopic and accelerator based platforms,homeland defense-personal protection equipment for emergency responders and large container inspection devices

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Tungsten: the Perfect Metal for Bullets and Missiles Part Two

Details: Category: Tungsten Information; Published on Tuesday, 02 September 2014 16:19; Written by jwy; Hits: 496

At SGS Carbide, a tool manufacturer just outside London, they use a lot of the stuff. They make a range of drill bits and cutting tools used in the aerospace, automobile and many other industries out of tungsten carbide - a super-hard compound of tungsten and carbon - cemented together with cobalt.

So how do you shape one of the most extreme materials on the planet?

You have to use the only thing tougher - diamonds. Even using diamond cutting tools the work involves an unholy battle, though you wouldn't know it inside SGS Carbide's factory. There's no smoke or sparks. All you hear is a quiet hum from the lathes and other machines.

Each one is contained in its own sound-proof box and has a sophisticated cooling system using refrigerated oil. But even with these state-of-the art machines it can take 10 minutes or more to cut a single drill bit. And they are expensive - a single drill bit can cost more than £500 ($750).

Yet, as more and more advanced alloys are used in industry, the demand for the super-strong, super-durable and super-accurate tools companies like SGS Carbide produce has grown. As most of the tungsten mined on the planet is used to make these tools, the price of the raw metal has been rising.

At the same time what may be tungsten's best-known industrial use now looks to be in terminal decline.

In a small room off one of the corridors of the chemistry department of University College London, Prof Andrea Sella holds up an old-fashioned incandescent light bulb. Through the clear glass I can see the fragile filament shiver as he gently shakes the bulb.

"The greater the current the hotter that little coil of tungsten gets and the brighter it glows," explains Sella.

Once, all our homes were illuminated by bulbs like these, but it took almost 100 years of trial and error to settle on tungsten. The great scientists and inventors who developed the first light bulbs tried out filaments of platinum, iridium, carbonised sewing thread and even bamboo - the latter both innovations of Thomas Edison's.

Then in 1908 another great American inventor, William D Coolidge, finally figured out how to make wires out of ultra-tough tungsten. These proved ideal filament material - strong, durable and heatable to extreme brightness without melting.

Tungsten filaments served us well for a century but the truth is they were always much better at producing heat than light - in some bulbs as much as 97% of the energy was lost as heat. That's why across the world incandescent bulbs are now being replaced by far more efficient compact fluorescents, light emitting diodes and other technologies.

But tungsten is still the basis of the two crucial technologies that help us see the world in very different ways.

Tungsten filaments generate the X-rays that give us a view inside our bodies and bones, and also the welds that hold ships, planes and bridges together. It is also used to form the emitter tips of the electron guns that allow electron microscopes to peer down and examine objects as tiny as single molecules.

But it was tungsten's density that earned it its name - it comes from the Swedish tung sten, heavy stone.

It is almost three times as dense as iron, almost twice that of lead and virtually the same as gold.

And, like the proliferation of new species during the Cambrian explosion, all sorts of weird applications have evolved to exploit tungsten's unique qualities.