From The University of Maryland And Colorado State University: “Compact Electron Accelerator Reaches New Speeds with Nothing But Light”

From The University of Maryland


Colorado State University

Dina Genkina

An image from a simulation in which a laser pulse (red) drives a plasma wave, accelerating electrons in its wake. The bright yellow spot is the area with the highest concentration of electrons. In an experiment, scientists used this technique to accelerate electrons to nearly the speed of light over a span of just 20 centimeters. (Credit Bo Miao/Institute of Research Electronics and Applied Physics)

Scientists harnessing precise control of ultrafast lasers have accelerated electrons over a 20-centimeter stretch to speeds usually reserved for particle accelerators the size of 10 football fields.

A team at the University of Maryland (UMD) headed by Professor of Physics and Electrical and Computer Engineering Howard Milchberg, in collaboration with the team of Jorge J. Rocca at Colorado State University, achieved this feat using two laser pulses sent through a jet of hydrogen gas. The first pulse tore apart the hydrogen, punching a hole through it and creating a channel of plasma. That channel guided a second, higher power pulse that scooped up electrons out of the plasma and dragged them along in its wake, accelerating them to nearly the speed of light in the process. With this technique, the team accelerated electrons to almost 40% of the energy achieved at massive facilities like the kilometer-long Linac Coherent Light Source (LCLS), the accelerator at The DOE’s SLAC National Accelerator Laboratory. The paper was published in the journal Physical Review X [below] on September 16, 2022

“This is the first multi-GeV electron accelerator powered entirely by lasers,” says Milchberg, who is also affiliated with the Institute of Research Electronics and Applied Physics at UMD. “And with lasers becoming cheaper and more efficient, we expect that our technique will become the way to go for researchers in this field.”

Motivating the new work are accelerators like LCLS, a kilometer-long runway that accelerates electrons to 13.6 billion electron volts (GeV)—the energy of an electron that’s moving at 99.99999993% the speed of light. LCLS’s predecessor is behind three Nobel-prize-winning discoveries about fundamental particles. Now, a third of the original accelerator has been converted to the LCLS, using its super-fast electrons to generate the most powerful X-ray laser beams in the world.

Scientists use these X-rays to peer inside atoms and molecules in action, creating videos of chemical reactions. These videos are vital tools for drug discovery, optimized energy storage, innovation in electronics, and much more.

Accelerating electrons to energies of tens of GeV is no easy feat. SLAC’s linear accelerator gives electrons the push they need using powerful electric fields propagating in a very long series of segmented metal tubes. If the electric fields were any more powerful, they would set off a lightning storm inside the tubes and seriously damage them. Being unable to push electrons harder, researchers have opted to simply push them for longer, providing more runway for the particles to accelerate. Hence the kilometer-long slice across northern California. To bring this technology to a more manageable scale, the UMD and CSU teams worked to boost electrons to nearly the speed of light using—fittingly enough—light itself.

“The goal ultimately is to shrink GeV-scale electron accelerators to a modest size room,” says Jaron Shrock, a graduate student in physics at UMD and co-first author on the work. “You’re taking kilometer-scale devices, and you have another factor of 1000 stronger accelerating field. So, you’re taking kilometer-scale to meter scale, that’s the goal of this technology.”

Creating those stronger accelerating fields in a lab employs a process called laser wakefield acceleration, in which a pulse of tightly focused and intense laser light is sent through a plasma, creating a disturbance and pulling electrons along in its wake.

“You can imagine the laser pulse like a boat,” says Bo Miao, a postdoctoral fellow in physics at the University of Maryland and co-first author on the work. “As the laser pulse travels in the plasma, because it is so intense, it pushes the electrons out of its path, like water pushed aside by the prow of a boat. Those electrons loop around the boat and gather right behind it, traveling in the pulse’s wake.”

Laser wakefield acceleration was first proposed in 1979 [Physical Review Letters] and demonstrated in 1995. But the distance over which it could accelerate electrons remained stubbornly limited to a couple of centimeters. What enabled the UMD and CSU team to leverage wakefield acceleration more effectively than ever before was a technique the UMD team pioneered [Physical Review Research] to tame the high-energy beam and keep it from spreading its energy too thin. Their technique punches a hole through the plasma, creating a waveguide that keeps the beam’s energy focused.

“A waveguide allows a pulse to propagate over a much longer distance,” Shrock explains. “We need to use plasma because these pulses are so high energy, they’re so bright, they would destroy a traditional fiber optic cable. Plasma cannot be destroyed because in some sense it already is.”

Their technique creates something akin to fiber optic cables—the things that carry fiber optic internet service and other telecommunications signals—out of thin air. Or, more precisely, out of carefully sculpted jets of hydrogen gas.

A conventional fiber optic waveguide consists of two components: a central “core” guiding the light, and a surrounding “cladding” preventing the light from leaking out. To make their plasma waveguide, the team uses an additional laser beam and a jet of hydrogen gas. As this additional “guiding” laser travels through the jet, it rips the electrons off the hydrogen atoms and creates a channel of plasma. The plasma is hot and quickly starts expanding, creating a lower density plasma “core” and a higher density gas on its fringe, like a cylindrical shell. Then, the main laser beam (the one that will gather electrons in its wake) is sent through this channel. The very front edge of this pulse turns the higher density shell to plasma as well, creating the “cladding.”

“It’s kind of like the very first pulse clears an area out,” says Shrock, “and then the high-intensity pulse comes down like a train with somebody standing at the front throwing down the tracks as it’s going.”

Using UMD’s optically generated plasma waveguide technique, combined with the CSU team’s high-powered laser and expertise, the researchers were able to accelerate some of their electrons to a staggering 5 GeV. This is still a factor of 3 less than SLAC’s massive accelerator, and not quite the maximum achieved with laser wakefield acceleration (that honor belongs to a team at The DOE’s Lawrence Berkeley National Labs). However, the laser energy used per GeV of acceleration in the new work is a record, and the team says their technique is more versatile: It can potentially produce electron bursts thousands of times per second (as opposed to roughly once per second), making it a promising technique for many applications, from high energy physics to the generation of X-rays that can take videos of molecules and atoms in action like at LCLS. Now that the team has demonstrated the success of the method, they plan to refine the setup to improve performance and increase the acceleration to higher energies.

“Right now, the electrons are generated along the full length of the waveguide, 20 centimeters long, which makes their energy distribution less than ideal,” says Miao. “We can improve the design so that we can control where they are precisely injected, and then we can better control the quality of the accelerated electron beam.”

While the dream of LCLS on a tabletop is not a reality quite yet, the authors say this work shows a path forward. “There’s a lot of engineering and science to be done between now and then,” Shrock says. “Traditional accelerators produce highly repeatable beams with all the electrons having similar energies and traveling in the same direction. We are still learning how to improve these beam attributes in multi-GeV laser wakefield accelerators. It’s also likely that to achieve energies on the scale of tens of GeV, we will need to stage multiple wakefield accelerators, passing the accelerated electrons from one stage to the next while preserving the beam quality. So there’s a long way between now and having an LCLS type facility relying on laser wakefield acceleration.”

Science papers:
Physical Review Letters 1979
Physical Review Research 2020
Physical Review X

In addition to Milchberg, Rocca, Shrock and Miao, authors on the paper included Linus Feder, formerly a graduate student in physics at UMD and now a postdoctoral researcher at the University of Oxford, Reed Hollinger, John Morrison, Huanyu Song, and Shoujun Wang, all research scientists at CSU, Ryan Netbailo, a graduate student in electrical and computer engineering at CSU, and Alexander Picksley, formerly a graduate student in physics at the University of Oxford and now a postdoctoral researcher at Lawrence Berkeley National Lab.

See the full article here .


Please help promote STEM in your local schools.

Stem Education Coalition

From Colorado State University is a public research university. The university is the state’s land grant university, and the flagship university of the Colorado State University System.

The current enrollment is approximately 37,198 students, including resident and non-resident instruction students and the University is planning on having 42,000 students by 2020. The university has approximately 2,000 faculty in eight colleges and 55 academic departments. Bachelor’s degrees are offered in 65 fields of study, with master’s degrees in 55 fields. Colorado State confers doctoral degrees in 40 fields of study, in addition to a professional degree in veterinary medicine.

U Maryland Campus

The University of Maryland is a public land-grant research university. Founded in 1856, The University of Maryland is the flagship institution of the University System of Maryland. It is also the largest university in both the state and the Washington metropolitan area, with more than 41,000 students representing all fifty states and 123 countries, and a global alumni network of over 388,000. Its twelve schools and colleges together offer over 200 degree-granting programs, including 92 undergraduate majors, 107 master’s programs, and 83 doctoral programs. The University of Maryland is a member of The Association of American Universities and competes in intercollegiate athletics as a member of the Big Ten Conference.

The University of Maryland’s proximity to the nation’s capital has resulted in many research partnerships with the federal government; faculty receive research funding and institutional support from agencies such as The National Institutes of Health (US), The National Aeronautics and Space Administration, The National Institute of Standards and Technology, The Food and Drug Administration, The National Security Agency, and The Department of Homeland Security. It is classified among “R1: Doctoral Universities – Very high research activity” and is labeled a “Public Ivy”, denoting a quality of education comparable to the private Ivy League. The University of Maryland is ranked among the top 100 universities both nationally and globally by several indices, including its perennially top-ranked criminology and criminal justice department.

In 2016, the University of Maryland-College Park and The University of Maryland- Baltimore formalized their strategic partnership after their collaboration successfully created more innovative medical, scientific, and educational programs, as well as greater research grants and joint faculty appointments than either campus has been able to accomplish on its own. According to The National Science Foundation, the university spent a combined $1.1 billion on research and development in 2019, ranking it 14th overall in the nation and 8th among all public institutions. As of 2021, the operating budget of the University of Maryland is approximately $2.2 billion.

On March 6, 1856, the forerunner of today’s University of Maryland was chartered as the Maryland Agricultural College. Two years later, Charles Benedict Calvert (1808–1864), a future U.S. Representative (Congressman) from the sixth congressional district of Maryland, 1861–1863, during the American Civil War and descendant of the first Lord Baltimores, colonial proprietors of the Province of Maryland in 1634, purchased 420 acres (1.7 km^2) of the Riversdale Mansion estate nearby today’s College Park, Maryland. Later that year, Calvert founded the school and was the acting president from 1859 to 1860. On October 5, 1859, the first 34 students entered the Maryland Agricultural College. The school became a land grant college in February 1864.

Following the Civil War, in February 1866, the Maryland legislature assumed half ownership of the school. The college thus became in part a state institution. By October 1867, the school reopened with 11 students. In 1868, the former Confederate admiral Franklin Buchanan was appointed President of the school, and in his tenure of just over a year, he reorganized it, established a system of strict economy in its business transactions, applied some of its revenues for the paying off of its debts, raised its standards, and attracted patrons through his personal influence: enrollment grew to 80 at the time of his resignation, and the school’s debt was soon paid off. In 1873, Samuel Jones, a former Confederate Major General, became president of the college.

Twenty years later, the federally funded Agricultural Experiment Station was established there. During the same period, state laws granted the college regulatory powers in several areas—including controlling farm disease, inspecting feed, establishing a state weather bureau and geological survey, and housing the board of forestry. Morrill Hall (the oldest instructional building still in use on campus) was built the following year.

The state took control of the school in 1916, and the institution was renamed Maryland State College. That year, the first female students enrolled at the school. On April 9, 1920, the college became part of the existing University of Maryland, replacing St. John’s College, Annapolis as the university’s undergraduate campus. In the same year, the graduate school on the College Park campus awarded its first PhD degrees and the university’s enrollment reached 500 students. In 1925 the university was accredited by The Association of American Universities.

By the time the first black students enrolled at the university in 1951, enrollment had grown to nearly 10,000 students—4,000 of whom were women. Prior to 1951, many black students in Maryland were enrolled at The University of Maryland-Eastern Shore.

In 1957, President Wilson H. Elkins made a push to increase academic standards at the university. His efforts resulted in the creation of one of the first Academic Probation Plans. The first year the plan went into effect, 1,550 students (18% of the total student body) faced expulsion.

On October 19, 1957, Queen Elizabeth II of the United Kingdom attended her first and only college football game at the University of Maryland after expressing interest in seeing a typical American sport during her first tour of the United States. The Maryland Terrapins beat the North Carolina Tar Heels 21 to 7 in the historical game now referred to as “The Queen’s Game”.

Phi Beta Kappa established a chapter at UMD in 1964. In 1969, the university was elected to The Association of American Universities. The school continued to grow, and by the fall of 1985 reached an enrollment of 38,679. Like many colleges during the Vietnam War, the university was the site of student protests and had curfews enforced by the National Guard.

In a massive restructuring of the state’s higher education system in 1988, the school was designated as the flagship campus of the newly formed University of Maryland System (later changed to the University System of Maryland in 1997), and was formally named the University of Maryland-College Park. All of the five campuses in the former network were designated as distinct campuses in the new system. However, in 1997 the Maryland General Assembly passed legislation allowing the University of Maryland-College Park to be known simply as The University of Maryland, recognizing the campus’ role as the flagship institution of the University System of Maryland.

The other University System of Maryland institutions with the name “University of Maryland” are not satellite campuses of the University of Maryland-College Park. The University of Maryland-Baltimore, is the only other school permitted to confer certain degrees from the “University of Maryland”.

In 1994, the National Archives at College Park completed construction and opened on a parcel of land adjoining campus donated by the University of Maryland, after lobbying by President William Kirwan and congressional leaders to foster academic collaboration between the institutions.

In 2004, the university began constructing the 150-acre (61 ha) “M Square Research Park,” which includes facilities affiliated with The Department of Defense , Food and Drug Administration, and the new National Center for Weather and Climate Prediction, affiliated with The National Oceanic and Atmospheric Administration. In May 2010, ground was broken on a new $128-million, 158,068-square-foot (14,685.0 m^2) Physical Science Complex, including an advanced quantum science laboratory.

The university’s Great Expectations campaign from 2006 to 2012 exceeded $1 billion in private donations.

The university suffered multiple data breaches in 2014. The first resulted in the loss of over 300,000 student and faculty records. A second data breach occurred several months later. The second breach was investigated by the FBI and Secret Service and found to be done by David Helkowski. Despite the attribution, no charges were filed. As a result of the data breaches, the university offered free credit protection for five years to the students and faculty affected.

In 2012, the University of Maryland-College Park and the University of Maryland- Baltimore united under the MPowering the State initiative to leverage the strengths of both institutions. The University of Maryland Strategic Partnership Act of 2016 officially formalized this partnership.

The University of Maryland’s University District Plan, developed in 2011 under President Wallace Loh and the College Park City Council, seeks to make the City of College Park a top 20 college town by 2020 by improving housing and development, transportation, public safety, local pre-K–12 education, and supporting sustainability projects. As of 2018, the university is involved with over 30 projects and 1.5 million square feet of development as part of its Greater College Park Initiative, worth over $1 billion in public-private investments. The university’s vision is to revitalize the campus to foster a dynamic and innovative academic environment, as well as to collaborate with the surrounding neighborhoods and local government to create a vibrant downtown community for students and faculty

In October 2017, the university received a record-breaking donation of $219.5 million from the A. James & Alice B. Clark Foundation, ranking among the largest philanthropic gifts to a public university in the country.

As of February 12, 2020, it has been announced that Darryll J. Pines will be the 34th President of the University of Maryland-College Park effective July 1, 2020. Darryll J. Pines is the dean of the A. James Clark School of Engineering and the Nariman Farvardin Professor of Aerospace Engineering since January 2009. Darryll J. Pines has been with the University of Maryland College Park for 25 years since he arrived in 1995 and started as an assistant professor.

In 2021, the university announced it had achieved its record goal of $1.5 billion raised in donations since 2018 as part of its Fearless Ideas: The Campaign for Maryland for investments in faculty, students, research, scholarships, and capital projects.

The university hosts “living-learning” programs which allow students with similar academic interests to live in the same residential community, take specialized courses, and perform research in those areas of expertise. An example is the Honors College, which is geared towards undergraduate students meeting high academic requirements and consists of several of the university’s honors programs. The Honors College welcomes students into a community of faculty and undergraduates. The Honors College offers seven living and learning programs: Advanced Cybersecurity Experience for Students, Design Cultures and Creativity, Entrepreneurship and Innovation, Honors Humanities, Gemstone, Integrated Life Sciences, and University Honors.

Advanced Cybersecurity Experience for Students (ACES), started in 2013, is directed by Michel Cukier and run by faculty and graduate students. ACES students are housed in Prince Frederick Hall and take a 14 credit, two year curriculum that educates future leaders in the field of cybersecurity. ACES also offers a complementary two-year minor in cybersecurity.

Design Cultures and Creativity (DCC), started in 2009, is directed by artist Jason Farman and run by faculty and graduate students. The DCC program encourages students to explore the relationship between emerging media, society, and creative practices. DCC students are housed in Prince Frederick residence hall together and take a 16 credit, two year interdisciplinary curriculum which culminates in a capstone.

Entrepreneurship and Innovation Program (EIP) is a living and learning program for Honors College freshmen and sophomores, helping build entrepreneurial mindsets, skill sets, and relationships for the development of solutions to today’s problems. Through learning, courses, seminars, workshops, competitions, and volunteerism, students receive an education in entrepreneurship and innovation. In collaboration with faculty and mentors who have launched new ventures, all student teams develop an innovative idea and write a product plan.

Honors Humanities is the honors program for beginning undergraduates with interests in the humanities and creative arts. The selective two-year living-learning program combines a small liberal arts college environment with the resources of a large research university.

Gemstone is a multidisciplinary four-year research program for select undergraduate honors students of all majors. Under guidance of faculty mentors and Gemstone staff, teams of students design, direct and conduct research, exploring the interdependence of science and technology with society.

Integrated Life Sciences (ILS) is the honors program for students interested in all aspects of biological research and biomedicine. The College of Computer, Mathematical, and Natural Sciences has partnered with the Honors College to create the ILS program, which offers nationally recognized innovations in the multidisciplinary training of life science and pre-medical students. The objective of the ILS experience is to prepare students for success in graduate, medical, dental, or other professional schools.

University Honors (UH) is the largest living-learning program in the Honors College and allows students the greatest independence in shaping their education. University Honors students are placed into a close-knit community of the university’s faculty and other undergraduates, committed to acquiring a broad and balanced education. Students choose from over 130 seminars exploring interdisciplinary topics in three broad areas: Contemporary Issues and Challenges, Arts and Sciences in Today’s World, and Using the World as a Classroom.

The College Park Scholars programs are two-year living-learning programs for first- and second-year students. Students are selected to enroll in one of 12 thematic programs: Arts; Business, Society, and the Economy; Environment, Technology, and Economy; Global Public Health; International Studies; Life Sciences; Media, Self, and Society; Public Leadership; Science and Global Change; Science, Discovery, and the Universe; Science, Technology, and Society. Students live in dormitories in the Cambridge Community on North Campus.

The nation’s first living-learning entrepreneurship program, Hinman CEOs, is geared toward students who are interested in starting their own business. Students from all academic disciplines live together and are provided the resources to explore business ventures.

The QUEST (Quality Enhancement Systems and Teams) Honors Fellows Program engages undergraduate students from business, engineering, and computer, mathematical, and physical sciences. QUEST Students participate in courses focused on cross-functional collaboration, innovation, quality management, and teamwork. The Department of Civil & Environmental Engineering (CEE) has also been long considered an outstanding engineering division of the university since its inception in 1908.

Other living-learning programs include: CIVICUS, a two-year program in the College of Behavioral and Social Sciences based on the five principles of civil society; Global Communities, a program that immerses students in a diverse culture (students from all over the world live in a community), and the Language House, which allows students pursuing language courses to live and practice with other students learning the same language.

The Mock Trial Team engages in intercollegiate mock trial competition. The team, which first began competing in 1990, has won five national championships (2008, 2000, 1998, 1996, 1992), which ranks the most of any university, and was also the national runner-up in 1992 and 1993.


On October 14, 2004, the university added 150 acres (61 ha) in an attempt to create the largest research park inside the Washington, D.C., Capital Beltway, formerly known as “M Square,” and now known as the “Discovery District”.

Many of the faculty members have funding from federal agencies such as the National Science Foundation, the National Institutes of Health, NASA, the Department of Homeland Security, the National Institute of Standards and Technology, and the National Security Agency. These relationships have created numerous research opportunities for the university including:

Taking the lead in the nationwide research initiative into the transmission and prevention of human and avian influenza.
Creating a new research center to study the behavioral and social foundations of terrorism with funding from the U.S. Department of Homeland Security
Launching the joint NASA-University of Maryland Deep Impact spacecraft in early January 2005.

The University of Maryland Libraries provide access to scholarly information resources required to meet the missions of the university.

The University of Maryland is an international center for the study of language, hosting the largest community of language scientists in North America, including more than 200 faculty, researchers, and graduate students, who collectively comprise the Maryland Language Science Center. Since 2008 the university has hosted an NSF-IGERT interdisciplinary graduate training program that has served as a catalyst for broader integrative efforts in language science, with 50 participating students and contributions from 50 faculty. The University of Maryland is also home to two key ‘migrator’ centers that connect basic research to critical national needs in education and national security: the Center for Advanced Study of Language (CASL) and the National Foreign Language Center.

The Center for American Politics and Citizenship provides citizens and policy-makers with research on issues related to the United States’ political institutions, processes, and policies. CAPC is a non-partisan, non-profit research institution within the Department of Government and Politics in the College of Behavioral and Social Sciences.

The Space Systems Laboratory researches human-robotic interaction for astronautics applications, and includes the only neutral buoyancy facility at a university.

The Joint Quantum Institute conducts theoretical and experimental research on quantum and atomic physics. The institute was founded in 2006 as a collaboration between the University of Maryland and the National Institute of Standards and Technology (NIST).

The Center for Technology and Systems Management (CTSM) aims to advance the state of technology and systems analysis for the benefit of people and the environment. The focus is on enhancing safety, efficiency and effectiveness by performing reliability, risk, uncertainty or decision analysis studies.

The Joint Global Change Research Institute was formed in 2001 by the University of Maryland and the DOE’s Pacific Northwest National Laboratory. The institute focuses on multidisciplinary approaches of climate change research.

The Center for Advanced Life Cycle Engineering (CALCE) was formed in 1985 at the University of Maryland. CALCE is dedicated to providing a knowledge and resource base to support the development of electronic components, products and systems.

The National Consortium for the Study of Terrorism and Responses to Terrorism (START) launched in 2005 as one of the Centers of Excellence supported by the Department of Homeland Security in the United States. START is focused on the scientific study of the causes and consequences of terrorism in the United States and around the world.

The university is tied for 58th in the 2021 U.S. News & World Report rankings of “National Universities” across the United States, and it is ranked tied for 19th nationally among public universities. The Academic Ranking of World Universities ranked Maryland as 43rd in the world in 2015. The 2017–2018 Times Higher Education World University Rankings placed Maryland 69th in the world. The 2016/17 QS World University Rankings ranked Maryland 131st in the world.

The university was ranked among Peace Corps’ 25 Top Volunteer-Producing Colleges for the tenth consecutive year in 2020. The University of Maryland is ranked among Teach for America’s Top 20 Colleges and Universities, contributing the greatest number of graduating seniors to its 2017 teaching corps. Kiplinger’s Personal Finance ranked the University 10th for in-state students and 16th for out-of-state students in its 2019 Best College Value ranking. Money Magazine ranked the university 1st in the state of Maryland for public colleges in its 2019 Best College for Your Money ranking.

For the fourth consecutive year in 2015, the university is ranked 1st in the U.S. for the number of Boren Scholarship recipients – with 9 students receiving awards for intensive international language study. The university is ranked as a Top Producing Institution of Fulbright U.S. Students and Scholars for the 2017–2018 academic year by the United States Department of State’s Bureau of Educational and Cultural Affairs.

In 2017, the University of Maryland was ranked among the top 50 universities in the 2018 Best Global Universities Rankings by U.S. News & World Report based on its high academic research performance and global reputation.

In 2021, the university was ranked among the top 10 universities in The Princeton Review’s annual survey of the Top Schools for Innovation & Entrepreneurship; this was the sixth consecutive such ranking.

WMUC-FM (88.1 FM) is the university non-commercial radio station, staffed by UMD students and volunteers. WMUC is a freeform radio station that broadcasts at 10 watts. Its broadcasts can be heard throughout the Washington metropolitan area. Notable WMUC alumni include Connie Chung, Bonnie Bernstein, Peter Rosenberg and Aaron McGruder.