Nuclear researchers in the Netherlands are securing their future by
investing in jewellery. The Dutch government-financed research institute
IRI in Delft is generating extra income by using its 2 megawatt nuclear
reactor to produce gemstones of a rare colour. The institute currently makes
250 000 guilders per year (about £76 000) from its sideline and the
institute thinks that this figure could be quadrupled – enough to pay the
salaries of at least six research assistants.
Since 1986 IRI has had to generate 10 per cent of its income from commercial
sources. One of these is the Dutch gemstone trader Van der Zalm, who was
in search of an irradiation facility that could colour topaz.
Topaz, which has the formula (Al2SiO4(F,OH)2) (the fluorine and hydroxyl
groups are interchangeable) occurs in a wide range of colours, from colourless
and yellow through orange and brown to violet and blue. Blue topaz is the
most popular and the most rare. People have known since the end of the 1950s
that colourless and yellow topaz can be turned into various shades of blue
by irradiation. To produce so-called Sky Blue, white topaz is irradiated
with electron beams. IRT of San Diego, is the world leader in electron beam
irradiation of topaz for this purpose.
But to obtain a darker shade of blue, so-called London Blue topaz, the
stone must be irradiated with neutrons – which requires a nuclear reactor.
Researchers still do not know exactly what happens to the gems during neutron
irradiation. They suspect that the fast neutrons make silicon-30 into silicon-31
and that this isotope degrades in turn within two hours into phosphorus-31.
This impurity in the crystal structure creates the blue colour. But there
must be an additional mechanism, because London Blue can also be produced
with intensive gamma radiation from cobalt-60. However, with the cobalt-60
method the gems have to be stored for up to four years to make sure the
radiation has dissipated, compared with between 2 and 12 months for neutron
irradiation.
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A few other nuclear research reactors produce London Blue topaz as a
sideline, but the Dutch IRI is optimistic that demand for irradiated gems
will increase, especially in Europe.
The IRI is also looking into the possibilities of irradiating diamonds,
to produce green, brown, yellow, pink or black ones. This would be more
profitable: the institute charges about 1.30 guilders per carat for topaz,
and for diamonds this figure could be as much as 40 guilders per carat.
![Astronomers have long known that understanding how star clusters come to be is key to unlocking other secrets of galactic evolution. Stars form in clusters, created when clouds of gas collapse under gravity. As more and more stars are born in a collapsing cloud, strong stellar winds, harsh ultraviolet radiation and the supernova explosions of massive stars eventually disperse the cloud, and their light can bear down on other star-forming regions in the galaxy. This process is called stellar feedback, and it means that most of the gas in a galaxy never gets used for star formation. Researching how star clusters develop can answer questions about star formation at a galactic scale. Now, the state of the art has been further developed with both Hubble and Webb working together to provide a broad-spectrum view of thousands of young star clusters. An international team of astronomers has pored over images of four nearby galaxies from the FEAST observing programme (#1783), trying to solve this mystery. Their results show that it is the most massive star clusters that clear away their gaseous shroud the fastest, and begin lighting their galaxy the earliest. The team identified nearly 9000 star clusters in the four galaxies in different evolutionary stages: young clusters just starting to emerge from their natal clouds of gas, clusters that had partially dispersed the gas (both from Webb images), and fully unobstructed clusters visible in optical light (found in Hubble images). With Webb???s ability to peer inside the gas clouds, they were able to then estimate the mass and age of each cluster from its light spectrum. This image shows a section of one of the spiral arms of Messier 51 (M51), one of the four galaxies studied in this work, as seen by Webb???s Near-Infrared Camera (NIRCam). The thick clumps of star-forming gas are shown here in red and orange, representing infrared light emitted by ionised gas, dust grains, and complex molecules such as polycyclic aromatic hydrocarbons (PAHs). Within these gas complexes, each tens or hundreds of light years across, Webb reveals the dense, extremely bright clusters of massive stars that have just recently formed. The countless stars strewn across the arm of the galaxy, many of which would be invisible to our eyes behind layers of dust, are also laid bare in infrared light. [Image description: A large, long portion of one of the spiral arms in galaxy M51. Red-orange, clumpy filaments of gas and dust that stretch in a chain from left to right comprise the arm. Shining cyan bubbles light up parts of the gas clouds from within, and gaps expose bright star clusters in these bubbles as glowing white dots. The whole image is dotted with small stars. A faint blue glow around the arm colours the otherwise dark background.]](https://images.newscientist.com/wp-content/uploads/2026/05/13114322/SEI_296271016.jpg)
