The UA9 experiment is investigating how crystals could help to steer particle beams in high-energy colliders
The UA9 collaboration is investigating how tiny bent crystals could improve how beams are collimated in modern hadron colliders such as the LHC.
The planes in crystalline solids can constrain the directions that charged particles take as they pass through. Physicists can use this "channelling" property of crystals to steer particle beams. In a bent crystal, for example, channelled particles follow the bend and can change their direction.
In high-energy hadron colliders, particles surrounding the beam core can be lost, damaging sensitive areas of theaccelerator. Multi-stage collimation systems are usually used to absorb this beam halo. These systems are composed of massive collimators and absorbers very close to the beam. Using a tiny bent crystal as a primary collimator could deflect halo particles coherently at large angles and direct them into a secondary collimator-absorber. In this way, the massive collimator-absorber could be placed at an increased distance from the beam, reducing the complexity of the system.
The UA9 collaboration has been testing this idea since 2009, using beams from theSuper Proton Synchrotron to do experiments on the collimation efficiency of silicon crystals.
Developing a crystal collimation system for a high-energy collider such as theLarge Hadron Collider (LHC) poses several challenges:
In steady conditions, a bent crystal could deposit up to 0.5 MW power in a small spot on the collimator-absorber that would need to sustain the power for several seconds without damage.The higher the particle energy, the lower the angular acceptance for channelling. UA9 is working in partnership with industrial companies to develop alignment mechanisms with high angular accuracy.And the growth rate of the beam halo is so slow that the first impacts on the crystal occur in a region not exceeding a few atomic layers. This imposes the requirement to have a flat surface parallel to the crystal planes with unprecedented tolerance.
The global requirements for crystal-assisted collimation call for technological breakthroughs in a multidisciplinary range; issues are related to beam manipulation, particle detectors, computing and data analysis. UA9 intends to provide solutions for them.
DiAmante makes synthetic diamonds for the semiconductor market. The company founder’s goal: ‘a diamond-based technology revolution.’ The tiny company’s competitors include diamond giant DeBeers.
The company and its products: DiAmante is a small, privately owned company that makes synthetic diamonds. The Miami-based firm, started by physicist John Janik (pictured above) in 2010, uses a special procedure developed by Janik to build highly specialized diamond crystals through chemical vapor deposition, a chemical process used in industry and research labs. “Think of a microwave oven on steroids,” said Janik, DiAmante’s president.
Janik places a tiny, flat diamond (the “seed” diamond) in a microwave chamber that will be filled with methane gas. When activated, the device deposits new diamond material on the seed atom by atom and layer by layer. “This is atomic-scale 3D printing,” he said. “We just happen to be printing blocks of diamond. The exact process is not patented, but it is a trade secret.”
After the growth process is complete (48 hours to two weeks, depending on the specifications of the diamond), the diamond is sliced into wafers for polishing and smoothing, for sale to labs and companies using semiconductors.
“We began producing gems and diamonds for optics and tooling, but now we are exclusively focused on diamonds for the semiconductor market,” Janik said.
The scientist sees great possibilities for diamonds in semiconductors, which are used in chips for electronic devices, and a new market in quantum computing. DiAmante makes diamonds classified as Type IIa, which in natural and synthetic states have almost no impurities and are excellent heat conductors. As electronic devices become more sophisticated, silicon-based semiconductors face problems in thermal conduction. Diamonds used with silicon could resolve these heat issues.
Getting started: “I left a cushy research job at the Carnegie Institution for Science in 2009 and moved to Miami,” Janik said. “I grew up in Maryland, but I love Miami.” Janik became interested in diamonds when he studied crystal growth as part of his doctoral program at Florida State University. “Reading papers on diamond growth made me realize there was an opportunity to help remake the world. We need new materials and diamond is one of them.” Janik was not attracted to teaching and decided to start his own business to focus on synthetic diamonds. Putting together seed money from family, friends and outside investors, he acquired the costly equipment needed to make diamonds (one device alone cost $400,000), began working with a small team and sold his first batch of diamonds for optical applications in 2011.
The difference: Using the manufacturing process developed by Janik, “we can produce material to meet specifications clients are looking for, including concentration of nitrogen, quality of surface finish and orientation of the crystal,” he said. A recent study by the University of Southern California showed that diamonds produced by DiAmante and a giant competitor (the DeBeers diamond group) were equally suitable for semiconductor use. A sample from Sumitomo, another competitor evaluated in the study, was not rated as suitable.
Sales: Revenue fell sharply after DiAmante switched from making gems in 2014 to producing diamond semiconductors. Currently, the company is working to increase its sales in diamond semiconductors and move to profitability. DiAmante’s tiny diamond wafers, designed according to the specifications of clients, can cost from $500 to $3,000 each, depending on their size, material quality, surface finish and other characteristics.
Competitors: DiAmante’s biggest competitor in semiconductors is Element Six, part of the De Beers group. In diamonds for tools, it’s Sumitomo.
Challenges: “We’ve received feedback from the scientific community, as well as clients, who say that our home run is in the foreseeable future,” Janik said. “We are officially in the game, and now it’s time to build our partner relationships to find the right fit for a team to play with us. We are looking for a capital infusion to demonstrate scalability of our manufacturing process and business model, and to take us to the next level.”
Glitch: “I didn’t have a clear vision when I started,” Janik said. “I started working on making gems and diamonds for tools and optics — the low-hanging fruit. Now I’m focusing exclusively on diamonds for semiconductors.”
Customers: Research labs, like the Quantum Photonics Laboratory at the Massachusetts Institute of Technology and the chemistry and physics departments at the University of Southern California, plus the defense industry. “We have purchased very low-content nitrogen diamond [from DiAmante] that we are intending to use for quantum information applications (QIP),” said Tim Schröder, a physicist at the MIT Quantum Photonics lab. Quantum physics refers to working with atomic and sub-atomic particles, and QIP refers to quantum computing. “DiAmante is a new player on the market, and we are always interested in trying out new products, new players, and in particular a diamond maker that does not only want to make gemstones for the jewelry industry.” Janik developed diamonds made according to MIT’s very demanding requirements. “Making a diamond for quantum information processing is not straightforward, but John’s diamonds have shown very promising properties,” he said.
Outside analysis: Diamond has the highest thermal conductivity of any material and can be used in semiconductor devices as silicon reaches its limits due to heat issues. But the cost of diamonds for this application is high. “If he [Janik] can cut production costs, there will be market opportunities in wireless systems and other sectors,” said Patrick Hindle, editor of Microwave Journal, an important source of information about radio frequency and microwave technology since 1958. The markets for semiconductors — wireless devices, appliances, electronics — are huge. “Like other small companies, DiAmante has the ability to focus primarily on sophisticated, high-tech products which require fewer skilled workers to produce the next generation of semiconductor-grade diamond wafers,” said Ion Benea, a physicist and vice president of operations for Hyprez Products at Engis Corp., a company specializing in industrial diamonds and superabrasive products. “Smaller companies are a lot more flexible and can play an important role in the development of new diamond products and technologies.”
Outlook: “There are physical limitations on packing more transistors onto silicon wafers due to heat issues,” Janik said. DiAmante’s diamond semiconductors could be the answer: “I want to help bring about a diamond-based technology revolution.” http://miamiherald.typepad.com/the-starting-gate/2016/06/diamante-creates-diamonds-for-high-tech-uses.htmlhttps://home.cern/about/experiments/ua9