From The Laboratory for Laser Energetics (LLE)
At
6.12.24
Sofia Tokar
LIGHT MY FIREBALL: Artist’s rendering of a black hole emitting a jet of hot gas known as plasma. An international team of scientists, including Rochester researchers, has generated plasma “fireballs” experimentally, opening a new frontier in laboratory astrophysics. (NASA/JPL-Caltech)
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An international team of scientists has developed a novel way to experimentally produce plasma ‘fireballs’ on Earth.
Black holes and neutron stars are among the densest known objects in the universe. Within and around these extreme astrophysical environments exist plasmas, the fourth fundamental state of matter alongside solids, liquids, and gases. Specifically, the plasmas at these extreme conditions are known as relativistic electron-positron pair plasmas because they comprise a collection of electrons and positrons—all flying around at nearly the speed of light.
While such plasmas are ubiquitous in deep space conditions, producing them in a laboratory setting has proved challenging.
Now, for the first time, an international team of scientists, including researchers from the University of Rochester’s Laboratory for Laser Energetics (LLE), has experimentally generated high-density relativistic electron-positron pair-plasma beams by producing two to three orders of magnitude more pairs than previously reported. The team’s findings appear in Nature Communications.
Fig. 1: Experimental setup.
Protons with 440 GeV/c momentum are extracted from the SPS ring with maximum intensity of 3 × 10^11 protons in a single bunch of duration 250 ps (1-σ), and transverse size σr = 1 mm. The transverse beam profile of the secondary beam is imaged using a 70 mm × 50 mm × 0.25 mm chromium-doped (Chromox) luminescence screen positioned 10 cm downstream of the target, and a blocker foil (50 μm aluminum) is used to minimize stray optical light. The Chromox screen is oriented at 45° to the beam path and viewed by a digital camera which has an exposure time of 24 ms to capture the entire scintillation of the screen. The 3.8 m standoff distance of the digital camera leads to image resolution of 50 μm, however the actual resolution is 100 μm due to the translucence of the Chromox. At a distance 2 m downstream of the target, electrons, and positrons are separated from the secondary beam and spectrally resolved using a magnetic spectrometer comprised of an electromagnet and a pair of luminescence screens (200 mm × 50 mm × 1 mm) centered at a distance 240 mm off-axis. 20-cm thick bricks of concrete (not shown in the diagram) are placed at the entrance of the electromagnet, leaving a 40 mm-wide aperture. Concrete is also placed to block the target from the direct view of the cameras to minimize speckle background arising on the camera images from the impact of high-energy hadrons scattered around the experimental area.
Fig. 2: Transverse beam profile imaged using a luminescence screen.
a Direct comparison of FLUKA Monte-Carlo simulations with raw image data obtained when the target is irradiated and the secondary beam is produced (‘Target in’), versus when the target is removed, and only the primary proton beam irradiates the screen (‘No target’). An absolute fluence calibration is obtained using the known density profile of the primary proton beam. b Integrated image intensity (total intensity) from 68 shots is converted to an absolute particle number, showing the case where the target is irradiated (red circles, 46 shots), and when it is removed (black diamonds, 22 shots). The error bars reflect the standard errors of the fitted parameters for each shot. FLUKA Monte-Carlo simulations of the predicted light yield are shown for both cases (black-dashed and red-dashed lines), showing good agreement with the experimental data. The blue dot-dashed line indicates the contribution from e± in the FLUKA simulation, highlighting that this is the dominant contribution to the enhanced signal.
See the science paper for further instructive material with images.
The breakthrough opens the doors to follow-up experiments that could yield fundamental discoveries about how the universe works.
“The laboratory generation of plasma ‘fireballs’ composed of matter, antimatter, and photons is a research goal at the forefront of high-energy-density science,” says lead author Charles Arrowsmith, a physicist from the University of Oxford who is joining LLE in the fall. “But the experimental difficulty of producing electron-positron pairs in sufficiently high numbers has, to this point, limited our understanding to purely theoretical studies.”
Rochester researchers Dustin Froula, the division director for plasma and ultrafast laser science and engineering at LLE, and Daniel Haberberger, a staff scientist at LLE, collaborated with Arrowsmith and other scientists to design a novel experiment harnessing the HiRadMat facility at the Super Proton Synchrotron (SPS) accelerator at the European Organization for Nuclear Research (CERN) in Geneva, Switzerland.
HOW IT WORKS: A proton (far left) from the Super Proton Synchrotron (SPS) accelerator at CERN impinges on carbon nuclei (small gray spheres). This produces a shower of various elementary particles, including a large number of neutral pions (orange spheres). As the unstable neutral pions decay, they emit two high-energy gamma rays (yellow squiggly arrows). These gamma rays then interact with the electric field of Tantalum nuclei (large gray spheres), generating electron and positron pairs and resulting in the novel electron-positron fireball plasma. Because of these cascade effects, a single proton can generate many electrons and positrons, making this process of pair plasma production extremely efficient. (University of Rochester Laboratory for Laser Energetics illustration / Heather Palmer)
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That experiment generated extremely high yields of quasi-neutral electron-positron pair beams using more than 100 billion protons from the SPS accelerator. Each proton carries a kinetic energy that is 440 times larger than its resting energy. Because of such large momentum, when the proton smashes an atom, it has sufficient energy to release its internal constituents—quarks and gluons—which then immediately recombine to produce a shower that ultimately decays into electrons and positrons.
In other words, the beam they generated in the lab had enough particles to start behaving like a true astrophysical plasma.
“This opens up an entirely new frontier in laboratory astrophysics by making it possible to experimentally probe the microphysics of gamma-ray bursts or blazar jets,” Arrowsmith says.
The team has also developed techniques to modify the emittance of pair beams, making it possible to perform controlled studies of plasma interactions in scaled analogues of astrophysical systems.
“Satellite and ground telescopes are not able to see the smallest details of those distant objects and so far we could only rely on numerical simulations. Our laboratory work will enable us to test those predictions obtained from very sophisticated calculations and validate how cosmic fireballs are affected by the tenuous interstellar plasma,” says coauthor Gianluca Gregori, a professor of physics at the University of Oxford.
Moreover, he adds, “The achievement highlights the importance of exchange and collaboration between experimental facilities around the world, especially as they break new ground in accessing increasingly extreme physical regimes.”
In addition to LLE, University of Oxford, and CERN, collaborating institutions on this research include the Science and Technology Facilities Council Rutherford Appleton Laboratory (STFC RAL), the University of Strathclyde, the Atomic Weapons Establishment in the UK, the Lawrence Livermore National Laboratory, the Max Planck Institute for Nuclear Physics, the University of Iceland, and the Instituto Superior Técnico in Portugal.
The team’s findings come amid ongoing efforts to advance plasma science by colliding ultrahigh-intensity lasers, an avenue of research that will be explored using the NSF OPAL Facility.
This project has received funding from the European Union’s Horizon Europe Research and Innovation program under Grant Agreement No 101057511 (EURO-LABS).
See the full article here .
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The Laboratory for Laser Energetics (LLE)
The Laboratory for Laser Energetics (LLE) is a scientific research facility which is part of the University of Rochester’s south campus, located in Brighton, New York. The lab was established in 1970 and its operations since then have been funded jointly; mainly by the United States Department of Energy, the University of Rochester and the New York State government. The Laser Lab was commissioned to serve as a center for investigations of high-energy physics, specifically those involving the interaction of extremely intense laser radiation with matter. Many types of scientific experiments are performed at the facility with a strong emphasis on inertial confinement, direct drive, laser-induced fusion, fundamental plasma physics and astrophysics using OMEGA. In June 1995, OMEGA became the world’s highest-energy ultraviolet laser. The lab shares its building with the Center for Optoelectronics and Imaging and the Center for Optics Manufacturing. The Robert L. Sproull Center for Ultra High Intensity Laser Research was opened in 2005 and houses the OMEGA EP laser, which was completed in May 2008.
The laboratory is unique in conducting big science on a university campus. More than 180 Ph.D.s have been awarded for research done at the LLE. During summer months the lab sponsors a program for high school students which involves local-area high school juniors in the research being done at the laboratory. Most of the projects are done on current research that is led by senior scientists at the lab.
The LLE was founded on the University of Rochester’s campus in 1970, by Dr. Moshe Lubin. Working with outside companies such as Kodak the team built Delta, a four beam laser system in 1972. Construction started on the current LLE site in 1976. The facility opened a six beam laser system in 1978 and followed with a 24 beam system two years later. In 2018, Donna Strickland and Gérard Mourou shared a Nobel prize for work they had undertaken in 1985 while at LLE. They invented a method to amplify laser pulses by “chirping” for which they would share the 2018 Nobel Prize in Physics. This method disperses a short, broadband pulse of laser light into a temporally longer spectrum of wavelengths. The system amplifies the laser at each wavelength and then reconstitutes the beam into one color. Chirp pulsed amplification became instrumental in building the National Ignition Facility at the DOE’s Lawrence Livermore National Laboratory and the Omega EP system. In 1995, the omega laser system was increased to 60 beams, and in 2008 the Omega extended performance system was opened.
The Guardian and Scientific American provided simplified summaries of the work of Strickland and Mourou: it “paved the way for the shortest, most intense laser beams ever created”. “The ultrabrief, ultrasharp beams can be used to make extremely precise cuts so their technique is now used in laser machining and enables doctors to perform millions of corrective” laser eye surgeries.
The University of Rochester is a private research university in Rochester, New York. The university grants undergraduate and graduate degrees, including doctoral and professional degrees.
The University of Rochester enrolls approximately 6,800 undergraduates and 5,000 graduate students. Its 158 buildings house over 200 academic majors. The University of Rochester is the 7th largest employer in the Finger lakes region of New York.
The College of Arts, Sciences, and Engineering is home to departments and divisions of note. The Institute of Optics was founded in 1929 through a grant from Eastman Kodak and Bausch and Lomb as the first educational program in the US devoted exclusively to Optics and awards approximately half of all Optics degrees nationwide and is widely regarded as the premier Optics program in the nation and among the best in the world.
The Departments of Political Science and Economics have made a significant and consistent impact on positivist social science since the 1960s and historically rank in the top 5 in their fields. The Department of Chemistry is noted for its contributions to synthetic Organic Chemistry, including the first lab-based synthesis of morphine. The Rossell Hope Robbins Library serves as The University of Rochester’s resource for Old and Middle English texts and expertise. The university is also home to Rochester’s Laboratory for Laser Energetics, a Department of Energy supported national laboratory.
The University of Rochester’s Eastman School of Music ranks highly among undergraduate music schools in the U.S. The Sibley Music Library at Eastman is the largest academic music library in North America and holds the third largest collection in the United States.
In its history The University of Rochester alumni and faculty have earned Nobel Prizes; Pulitzer Prizes; Grammy Awards; Guggenheim Awards; there are members of National Academy of Sciences; National Academy of Engineering; National Academy of Inventors; and National Academy of Inventors Hall of Fame; and Rhodes Scholarships.
Early history
The University of Rochester traces its origins to The First Baptist Church of Hamilton (New York) which was founded in 1796. The church established the Baptist Education Society of the State of New York later renamed the Hamilton Literary and Theological Institution in 1817. This institution gave birth to both Colgate University and the University of Rochester. Its function was to train clergy in the Baptist tradition. When it aspired to grant higher degrees, it created a collegiate division separate from the theological division.
The collegiate division was granted a charter by the State of New York in 1846 after which its name was changed to Madison University. John Wilder and the Baptist Education Society urged that the new university be moved to Rochester, New York. However, legal action prevented the move. In response, dissenting faculty, students, and trustees defected and departed for Rochester, where they sought a new charter for a new university.
Madison University was eventually renamed as Colgate University.
Founding
Asahel C. Kendrick- professor of Greek- was among the faculty that departed Madison University for The University of Rochester. Kendrick served as acting president while a national search was conducted. He reprised this role until 1853 when Martin Brewer Anderson of the Newton Theological Seminary in Massachusetts was selected to fill the inaugural posting.
The University of Rochester’s new charter was awarded by the Regents of the State of New York on January 31, 1850. The charter stipulated that The University of Rochester have $100,000 in endowment within five years upon which the charter would be reaffirmed. An initial gift of $10,000 was pledged by John Wilder which helped catalyze significant gifts from individuals and institutions.
Classes began that November with approximately 60 students enrolled including 28 transfers from Madison. From 1850 to 1862 the university was housed in the old United States Hotel in downtown Rochester on Buffalo Street near Elizabeth Street- today West Main Street near the I-490 overpass. On a February 1851 visit Ralph Waldo Emerson said of the university:
“They had bought a hotel, once a railroad terminus depot, for $8,500, turned the dining room into a chapel by putting up a pulpit on one side, made the barroom into a Pythologian Society’s Hall, & the chambers into Recitation rooms, Libraries, & professors’ apartments, all for $700 a year. They had brought an omnibus load of professors down from Madison bag and baggage… called in a painter and sent him up the ladder to paint the title “University of Rochester” on the wall, and they had runners on the road to catch students. And they are confident of graduating a class of ten by the time green peas are ripe.”
For the next 10 years The University of Rochester expanded its scope and secured its future through an expanding endowment; student body; and faculty. In parallel a gift of 8 acres of farmland from local businessman and Congressman Azariah Boody secured the first campus of The University of Rochester upon which Anderson Hall was constructed and dedicated in 1862. Over the next sixty years this Prince Street Campus grew by a further 17 acres and was developed to include fraternity houses; dormitories; and academic buildings including Anderson Hall; Sibley Library; Eastman and Carnegie Laboratories the Memorial Art Gallery and Cutler Union.
Twentieth century
Coeducation
The first female students were admitted in 1900- the result of an effort led by Susan B. Anthony and Helen Barrett Montgomery. During the 1890s a number of women took classes and labs at The University of Rochester as “visitors” but were not officially enrolled nor were their records included in the college register. President David Jayne Hill allowed the first woman- Helen E. Wilkinson- to enroll as a normal student although she was not allowed to matriculate or to pursue a degree. Thirty-three women enrolled among the first class in 1900 and Ella S. Wilcoxen was the first to receive a degree in 1901. The first female member of the faculty was Elizabeth Denio who retired as Professor Emeritus in 1917. Male students moved to River Campus upon its completion in 1930 while the female students remained on the Prince Street campus until 1955.
Expansion
Major growth occurred under the leadership of Benjamin Rush Rhees over his 1900-1935 tenure. During this period George Eastman became a major donor giving more than $50 million to the university during his life. Under the patronage of Eastman the Eastman School of Music was created in 1921. In 1925 at the behest of the General Education Board and with significant support for John D. Rockefeller George Eastman and Henry A. Strong’s family medical and dental schools were created. The university award its first Ph.D that same year.
During World War II The University of Rochester was one of 131 colleges and universities nationally that took part in the V-12 Navy College Training Program which offered students a path to a Navy commission. In 1942, The University of Rochester was invited to join the Association of American Universities as an affiliate member and it was made a full member by 1944. Between 1946 and 1947 in infamous uranium experiments researchers at the university injected uranium-234 and uranium-235 into six people to study how much uranium their kidneys could tolerate before becoming damaged.
In 1955 the separate colleges for men and women were merged into The College on the River Campus. In 1958 three new schools were created in engineering, business administration and education. The Graduate School of Management was named after William E. Simon- former Secretary of the Treasury in 1986. He committed significant funds to the school because of his belief in the school’s free market philosophy and grounding in economic analysis.
Financial decline and name change controversy
Following the princely gifts given throughout his life George Eastman left the entirety of his estate to The University of Rochester after his death by suicide. The total of these gifts surpassed $100 million before inflation and as such The University of Rochester enjoyed a privileged position amongst the most well endowed universities. During the expansion years between 1936 and 1976 The University of Rochester’s financial position ranked third, near Harvard University’s endowment and the University of Texas System’s Permanent University Fund . Due to a decline in the value of large investments and a lack of portfolio diversity The University of Rochester ‘s place dropped to the top 25 by the end of the 1980s. At the same time the preeminence of the city of Rochester’s major employers began to decline.
In response The University of Rochester commissioned a study to determine if the name of the institution should be changed to “Eastman University” or “Eastman Rochester University”. The study concluded a name change could be beneficial because the use of a place name in the title led respondents to incorrectly believe it was a public university, and because the name “Rochester” connoted a “cold and distant outpost.” Reports of the latter conclusion led to controversy and criticism in the Rochester community. Ultimately, the name “The University of Rochester” was retained.
Renaissance Plan
In 1995 The University of Rochester president Thomas H. Jackson announced the launch of a “Renaissance Plan” for The University of Rochester that reduced enrollment from 4,500 to 3,600 creating a more selective admissions process. The plan also revised the undergraduate curriculum significantly creating the current system with only one required course and only a few distribution requirements known as clusters. Part of this plan called for the end of graduate doctoral studies in Chemical Engineering; comparative literature; linguistics; and Mathematics, the last of which was met by national outcry. The plan was largely scrapped and Mathematics exists as a graduate course of study to this day.
Twenty-first century
Meliora Challenge
Shortly after taking office university president Joel Seligman commenced the private phase of the “Meliora Challenge”- a $1.2 billion capital campaign- in 2005. The campaign reached its goal in 2015- a year before the campaign was slated to conclude. In 2016, The University of Rochester announced the Meliora Challenge had exceeded its goal and surpassed $1.36 billion. These funds were allocated to support over 100 new endowed faculty positions and nearly 400 new scholarships.
The Mangelsdorf Years
On December 17, 2018 The University of Rochester announced that Sarah C. Mangelsdorf would succeed Richard Feldman as President of the University. Her term started in July 2019 with a formal inauguration following in October during Meliora Weekend. Mangelsdorf is the first woman to serve as President of the University and the first person with a degree in psychology to be appointed to Rochester’s highest office.
In 2019 students from China mobilized by the Chinese Students and Scholars Association (CSSA) defaced murals in the University’s access tunnels which had expressed support for the 2019 Hong Kong Protests, condemned the oppression of the Uighurs, and advocated for Taiwanese independence. The act was widely seen as a continuation of overseas censorship of Chinese issues. In response a large group of students recreated the original murals. There have also been calls for Chinese government run CSSA to be banned from campus.
Research
The University of Rochester is a member of the Association of American Universities and is classified among “R1: Doctoral Universities – Very High Research Activity”.
Rochester ranks very highly nationally in research spending.
Some of the major research centers include the Laboratory for Laser Energetics, a laser-based nuclear fusion facility, and the extensive research facilities at the University of Rochester Medical Center.
Recently The University of Rochester has also engaged in a series of new initiatives to expand its programs in Biomedical Engineering and Optics including the construction of the new $37 million Robert B. Goergen Hall for Biomedical Engineering and Optics on the River Campus.
Other new research initiatives include a cancer stem cell program and a Clinical and Translational Sciences Institute. The University of Rochester also has the ninth highest technology revenue among U.S. higher education institutions. Notable patents include Zoloft and Gardasil. WeBWorK, a web-based system for checking homework and providing immediate feedback for students was developed by The University of Rochester professors Gage and Pizer. The system is now in use at over 800 universities and colleges as well as several secondary and primary schools. The University of Rochester scientists work in diverse areas. For example, physicists developed a technique for etching metal surfaces such as platinum; titanium; and brass with powerful lasers enabling self-cleaning surfaces that repel water droplets and will not rust if tilted at a 4 degree angle; and medical researchers are exploring how brains rid themselves of toxic waste during sleep.
The new supercomputer enables a four-fold increase in high-performance computing to simulate high-energy-density physics and inertial confinement fusion experiments.
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