Fermi National Accelerator Laboratory (FNAL)

Fermilab scientist Jayakar ‘Charles’ Thangaraj has been awarded $200,000 from the Accelerator Stewardship Program of the U.S. Department of Energy to develop the design of a new, compact high-power accelerator. Collaborators are conceptualizing the potential use of this electron accelerator, based on superconducting radio-frequency (SRF) technology, in treating municipal biosolids and wastewater in collaboration with the Metropolitan Water Reclamation District (MWRD) of Greater Chicago.

The grant builds on the previous work conducted by a team at the Illinois Accelerator Research Center (IARC) at Fermilab, specifically the work to design a one-megawatt electron accelerator – toward the top end of typical industrial electron accelerator power.

The results of simulations from that initial effort were encouraging enough that the IARC team proposed an accelerator system with a truly revolutionary 10-megawatt power output.

“Our simulations gave us positive results and encouraged us to pursue a higher-powered machine,” said Thangaraj, who is the science and technology manager at IARC. “I am thrilled to hear this proposal was awarded, we are ready to investigate.”

Municipal biosolids produced at MWRD’s water reclamation plants are generated through processes to remove larger, suspended solids from the water and organic pollutants, as well as to physically or chemically kill pathogens. In the Chicago area, treated water is then allowed to flow into local waterways without risk of harming the ecosystem. The byproducts from the water reclamation process are further treated to recover nutrients and energy and converted into a final product as biosolids that are beneficially used as fertilizer or soil amendment.

With an electron accelerator, the flowing water is exposed to a beam of highly energetic electrons, which create radicals in the solution that can disrupt chemical bonds. This will help kill pathogens in the water and the biosolids and increase the efficiency of recovering energy and nutrients from the biosolids.

This electron beam treatment technique has a few advantages. Firstly, because the treatment technique is physical and involves only a burst of electrons, the need for possibly harmful additional chemicals can be eliminated. Commonly used chemicals for inactivating pathogens in water, such as chlorine and ozone, can leave further residuals in the water, can be expensive to produce, or require filtration to avoid toxicity to workers at treatment centers.

Further, the technique can destroy organic contamination and pharmaceuticals that might otherwise survive conventional treatment.

While chemical and biological treatment processes require carefully controlled conditions and target specific contaminants, electron beam treatment is broadly effective and requires only an electricity supply to run.

The treatment process is also rapid, able to handle chemical and biological hazards simultaneously, and especially with the increased portability of this new conceptual design from IARC, easily adaptable to existing plant designs and layouts.

Accelerators for social impact

Fermilab’s mission is to build and operate world-class particle physics facilities for discovery science. In building such high-precision physics machines, the technologies that are developed can also have an impact on U.S. industry and wider society. IARC’s complementary mission is to take cutting-edge inventions from the lab and adopt those into real-life products and solutions. The IARC compact accelerator is a case in point.

“IARC’s compact SRF accelerator is a pioneer in the industrial accelerator space,” Thangaraj said.

Several Fermilab-developed technologies are combined to build this novel accelerator, and the platform technology has a range of potential applications, including extending the longevity of pavements and medical sterilization.

New innovations

SRF accelerators, including those currently used at Fermilab, rely on being cooled down to around 2 Kelvin, colder than the 2.7 Kelvin (minus 270.5 degrees Celsius) of outer space. The components need to operate at cold temperatures to be able to superconduct: the ‘S’ in SRF. The typical way to do this is by immersing the cavities in liquid helium and pumping on the helium to lower its pressure. However, producing and maintaining subatmospheric liquid helium requires complex cryogenic plants – a factor that severely limits the portability and therefore the potential applications of SRF accelerators in industrial environments.

“We are able to do away with liquid helium through a combination of recent advancements in superconducting surface science and cryogenics technology. This allows us to operate at a higher superconducting temperature in our cavities and cool them in a novel way,” said Thangaraj, who was also awarded $1.47 million to develop this crucial Fermilab-patented technology from the Laboratory Directed Research Development program.

“Breaking the need for a supply of liquid helium makes the accelerator very attractive for installation within MWRD’s existing infrastructure,” he said.

Though such real-life solutions are exciting and promising, the reality remains a few years away. Nevertheless, IARC has already started talking to several stakeholders in the industry.

“When we turn the tap or twist open a bottle, we often don’t realize that behind such modern conveniences are some of the most amazing technologies that deliver clean and safe water,” Thangaraj said. “Water is such a precious resource on our planet. We must use our best technologies to protect it. Electron beam technology could be a practical and effective way for water treatment in the future. Now is the time to develop it.”

What does running large particle accelerators have in common with hospital imaging scanners? The operating system for both requires high performance and stability.

Fermilab first developed Scientific Linux as an open-source operating system in 2004 to fulfill exactly these demands, and it continues to release new versions.

GE Healthcare, a company that builds medical imaging equipment, found that it had the same needs when it came to operating systems. It now employs Scientific Linux as a foundation for its own, customized HELiOS, which stands for Healthcare Enterprise Linux Operating System.

According to GE, more than 30,000 medical imaging machines worldwide use this SL-based operating system to search for broken bones, tumors and other injuries on organs, and their numbers will easily double in the next two years. On GE machines, HELiOS manages the whole process, from taking an image of a patient to reconstructing the image and even displaying it for doctors.

At Fermilab, Scientific Linux runs on all computers for particle accelerator operation and on most data taking systems for experiments. Many scientists use it every day to write simulations or perform data analysis.

“Originally we created Scientific Linux for the high-energy physics community, but it was never exclusively for them. Everybody can download and use it,” said Connie Sieh, Fermilab computer specialist and co-developer of Scientific Linux. “We were really surprised when GE contacted us. We had never expected that our SL would spread that far or that it would be used in medicine.”

GE initiated the contact with Fermilab about the software, discussing customization issues. From there, the two institutions began a regular, informal exchange of knowledge and ideas to improve both operating systems.

Fermilab uses Scientific Linux to control and monitor all accelerators on site from the main accelerator operations room. Photo credit: Reidar Hahn

“Now we talk and meet on a regular basis, which is great, and Fermilab assistance is very welcome,” said James Foris, senior system engineer at GE Healthcare. “This exchange really reflects the open-source mentality we all share in software development.”

Fermilab develops Scientific Linux in the same way most Linux distributions are developed: The source code is freely available and can be changed or customized. Fermilab’s computing experts continually customize the Red Hat Linux distribution to provide a stable, scalable and extensible operating system to support the needs of the scientific community. GE then leverages Fermilab’s Scientific Linux to create HELiOS, a Linux distribution for healthcare applications.

“We use this style of software development for our products to ensure that our customers get a stable system tailored to their needs,” Foris said. “And avoiding the extra costs for software licenses always helps.”

One other attractive feature of Scientific Linux is its long lifespan: A single SL version, such as SL version 7, is supported by updates for 10 years. (A quick lesson in new versions versus new updates: Installing a new version, say version 7, is like buying a new car, while updating a version, say from version 7 to 7.1, is like getting an oil change or new tires. An update includes some new features, but never a major change in the whole design of the software. Major changes are released as new versions, such as SL version 8.)

For GE, this long lifespan means that they can support the software of their magnetic resonance imagers and other systems for 10 years, providing publicly reviewed and available bug fixes and security updates, without making major changes, which can be inconvenient for their customers.

Fermilab’s computing experts increase the security of the operating system to fulfill the standards of usage at a Dpartment of Energy national laboratory. They implement features for easy access to file sharing and data storage, which are crucial for high-performance computing. GE uses those computing features for their own image reconstruction.

Scientific Linux was created for running accelerators and calculating particle collisions, and now its use has extended to our everyday lives, assisting people worldwide with their health and well-being.

The Scientific Linux team wishes to thank Red Hat for its contributions to maintaining an open, free, collaborative, and transparent open source community for software development.

Scientists are a step closer to building an intense electron beam source without a laser. Using Fermilab’s High-Brightness Electron Source Lab (HBESL), a team led by RadiaBeam Technologies is testing a carbon nanotube cathode—about the size of a nickel—that completely eliminates the need for a room-sized laser system. Tests with the nanotube cathode have produced beam currents a thousand to a million times greater than the one generated with a large, pricey laser system. Fermilab was sought out to test the experimental cathode because of its capability and expertise for handling intense electron beams, one of relatively few labs that can support this project. A U.S. Department of Energy Small Business Innovation Research grant funds the collaboration between California-based RadiaBeam, Fermilab, and Northern Illinois University.

The new cathode appears at first glance like a smooth black button, but at the nanoscale it it is made of millions of nanotubes that function like tiny lightning rods. When a strong electric field is applied, it pulls streams of electrons off the surface of the cathode, creating the electron beam. The exceptional strength of carbon nanotubes prevents the cathode from being destroyed. Traditionally, accelerator scientists use lasers to strike cathodes in order to eject electrons through photoemission. The electric and magnetic fields of the particle accelerator then organize the electrons into a beam. The tested nanotube cathode requires no laser: it only needs the electric field already generated by an accelerator to siphon the electrons off, a process dubbed field emission.

This new technology has extensive applications in medical equipment and national security, since an electron beam is a critical component in generating X-rays. While carbon nanotube cathodes have been studied extensively in academia, Fermilab is the first facility to test the technology within a full-scale setting. This remarkable result means that electron beam equipment used in industry may become not only less expensive and more compact, but also more efficient. A laser like the one in HBESL runs close to half a million dollars, about one hundred times more expensive than RadiaBeam's cathode.

The team continues to study ways to optimize the design of the cathode to prevent any smaller, adverse effects that may take place within the beam assembly. Future research also may focus on redesigning an accelerator that natively incorporates the carbon nanotube cathode to avoid any compatibility issues. The work represents the kind of research that will be further enabled at the Illinois Accelerator Research Center — a facility that brings together Fermilab expertise with that of industry and academia, for the benefit of the U.S. economy.

Fermilab has developed a large area, highly segmented camera system with pixels capable of handling signals of up to five orders of magnitude dynamic range and in-situ storage of images acquired at high speed (Multi-megahertz frequency). 

The system consists of three major components: 1) a wafer-scale sensor with approximately a million pixels, 2) a Silicon Interposer (also called a Silicon Printed Circuit Board or SiPCB), which serves as an interconnection device and pitch adapter between the sensor wafer pixels and a number of smaller readout ASICs, and 3) the custom front-end readout ASIC with a few tens of thousands of pixels, which implements a novel design concept to achieve high dynamic range while maintaining both small pixel area and low power dissipation.

The system is seamless up to 20cm x20cm with pixel sizes on the order of 100-150um (side) without any dead space. Each pixel can integrate a wide dynamic range charge (1 fC to 100 pC) that is equivalent to the range of 1-105 photons impinging on a single pixel at a multi megahertz frequency (6.5MHz). In addition to high energy physics applications, the system has significant potential for materials research and medical imaging applications.