Result Tickler: Lead Nucleus May Bury
Positive Side Under Neutral Facade

PRex_3c58_NeutronStar.jpg

The Lead (Pb) Radius Experiment (PREx) collaboration announced its preliminary result at the American Physical Society's April Meeting in Anaheim. The result is important for the understanding of the structure of heavy nuclei and for the theoretical equations that describe the life cycles of neutron stars. Pictured is 3C58, the remnant of a supernova. This image, from the Chandra telescope, shows the central pulsar – a rapidly rotating neutron star formed in the supernova event. Image by NASA/CXC/SAO/P.Slane et al.

A novel experiment performed last year at Jefferson Lab suggests that the nucleus of a lead atom buries its positive "personality" beneath a neutral exterior. The preliminary result is consistent with the idea that neutrons form a kind of "neutron skin" around the protons in the nucleus in heavy nuclei, such as lead.

The Lead (Pb) Radius Experiment (PREx) collaboration announced the preliminary result at a seminar at Jefferson Lab and at the American Physical Society's April Meeting in Anaheim. The result is important for the understanding of the structure of heavy nuclei and for the theoretical equations that describe the life cycles of neutron stars...... more


JLab to Collaborate on Accelerator Development With India

DAEIndia.jpgAn agreement, announced on July 25, between the U.S. Department of Energy and the Indian Department of Atomic Energy to advance scientific discovery......more

 

MIT Professor Wins First JSA Outstanding Nuclear Physicist Award

MIT-JSA.jpg MIT Professor William Bertozzi, recognized as a world leader and innovator in the field of experimental electromagnetic nuclear physics.....more

 

2010 Thesis Prize Winner Recognized at Users Meeting

thesiswinner.jpg If Xin Qian had his way, all graduate students in experimental nuclear physics would get hands-on experience working with equipment......more


Below the Fold:

 

Result Tickler: Lead Nucleus May Bury
Positive Side Under Neutral Facade

HallA.jpg

Experiment (PREx) was carried out in Hall A during 2010.

A novel experiment performed last year at Jefferson Lab suggests that the nucleus of a lead atom buries its positive "personality" beneath a neutral exterior. The preliminary result is consistent with the idea that neutrons form a kind of "neutron skin" around the protons in the nucleus in heavy nuclei, such as lead.

The Lead (Pb) Radius Experiment (PREx) collaboration announced the preliminary result at a seminar at Jefferson Lab and at the American Physical Society's April Meeting in Anaheim. The result is important for the understanding of the structure of heavy nuclei and for the theoretical equations that describe the life cycles of neutron stars.

“What this first measurement implies is that neutrons occupy a larger volume than the protons in heavy nuclei,” said Krishna Kumar, a professor at the University of Massachusetts, Amherst, and a spokesperson for the experiment.

Prior to this experiment, the best estimates of the neutron radius came from nuclear theory, where models were constrained primarily by data other than measurements of neutron radii. In a heavy nucleus, such as lead (208Pb), the fractional difference between the neutron radius and the proton radius was previously expected to be several percent.

PREx measured the neutron radius in a clean and model-independent way, providing the first quantitative evidence of the presence of the neutron skin. The PREx result suggests that neutrons form a neutron skin around the protons inside heavy nuclei, but only at the 95 percent confidence level.

"The PREx measurement provides a first independent check of basic nuclear theory," said Kent Paschke, an assistant professor at the University of Virginia and a spokesperson for the experiment.

Bob McKeown, Jefferson Lab deputy director of science and technology, agreed. "Although higher precision is desirable to further constrain nuclear theory, the PREx result is a substantial experimental statement – one that we could not state before."

In the experiment, a beam of polarized (spinning) electrons was sent into a sandwich-style, carbon-lead-carbon target. The carbon sandwich allowed experimenters to draw heat from the target, keeping it from melting from the heavy bombardment of the high-intensity electron beam. Lead has a low melting point.

Electrons in the beam could interact with nuclei in the target through one of two fundamental forces: the electromagnetic force or the weak force. Throughout the experimental run, the polarized electron beam was flipped from one polarization (electrons spinning in one direction) to its opposite. This polarization flip allowed experimenters to exploit differences in how electrons interact with target particles via the electromagnetic versus the weak force.

The electromagnetic force is mirror-symmetric, whereas the weak force is not. Therefore, electrons that interacted with the target through the electromagnetic force did so regardless of the polarization. However, electrons that interacted with the target through the weak force preferentially interacted when the beam polarization was in one direction versus the other. Further, and even more importantly, the weak force preferentially interacts with neutrons.

By probing the difference in the number of electrons that interacted with the lead target in one polarization state versus the other, experimenters were able to tease out a measurement of the neutron radius in lead.

"The techniques that we used capitalized on two unique capabilities only available at Jefferson Lab: high-intensity, clean electron beam and the ability to flip the electron beam's polarization," said Robert Michaels, a spokesperson on the experiment and interim leader of Jefferson Lab's Hall A. "No one has done a parity-violation experiment on a heavy nucleus before using a clean probe, such as electron scattering. Jefferson Lab's unique capabilities made this experiment possible."

The ultimate goal of PREx was a measurement of the neutron radius to 1 percent accuracy. According to Kumar, this first run proved quite challenging.

"The experiment encountered several technical issues. Therefore, this result didn't achieve the full statistics due to the time required to solve these technical issues," Kumar said. "We now know how to make a more precise measurement than we have made so far."

During the first run, the experimenters ran into trouble stemming from damaged equipment due to the high-intensity electron beam and the thick target used, including a malfunctioning vacuum system, a cracked O-ring and other problems.

"For instance, due to the complexity of the downstream beamline, we originally used a soft O-ring near the target. The O-ring was eventually damaged by the radiation. So, to solve that technical issue, we plan to change out the O-ring for a metal seal," Kumar explained.

Michaels said the collaboration will present a new run plan to the Program Advisory Committee, a panel of scientists who prioritize proposed experiments for Jefferson Lab's CEBAF accelerator and experimental halls.

"We have now demonstrated the capability to perform this experiment. We now have all of the technical issues under control and can perform this experiment at a much higher precision. We plan to tweak the design of the experiment and apply for another run," Michaels said.

Kumar agreed. "Through our experience over the course of the first experiment run, we can demonstrate to the Program Advisory Committee that we have all of these problems under control and that we can run with the efficiency that was originally projected."

More than 100 researchers from more than 30 institutions worked on the experiment, which was installed, commissioned and conducted March-June 2010.

This work was supported in part by the Department of Energy's Office of Science, the National Science Foundation and the Istituto Nazionale di Fisica Nucleare.

By Kandice Carter
Science writer

For more information visit these links:
General description of the PREx Experiment
Star experiment article

 

JLab to Collaborate on Accelerator Development With India

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An agreement, announced on July 25, between the U.S. Department of Energy and the Indian Department of Atomic Energy to advance scientific discovery in accelerator and particle detector research could soon provide new collaborations and expanded opportunities for Jefferson Lab, according to a DOE news release.

The agreement seeks to leverage U.S. and Indian scientific, technical, and engineering expertise in the pursuit of new discoveries and the development of new technologies that enhance scientific understanding and ultimately could lead to advances in clean energy.

The agreement will expand research collaborations in superconducting radiofrequency (SRF) accelerator technology, heavy ion physics, and particle detector development at Jefferson Lab, as well as at DOE’s Fermi National Accelerator Laboratory and Brookhaven National Laboratory. 

"This agreement is the latest step in the deepening cooperation between the U.S. and India on a range of clean energy and scientific fronts. Working together, we will be able to further our collective understanding of accelerators and high-energy particles, pursue new technologies and scientific discoveries, and advance our shared clean energy goals," said Deputy Secretary of Energy Daniel Poneman, who signed the agreement in New Delhi.

The DOE news release is available online at: http://energy.gov/news/10441.htm

 

MIT Professor Wins First
JSA Outstanding Nuclear Physicist Award

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MIT Professor William Bertozzi is the first recipient of the Outstanding Nuclear Physicist Award presented by Jefferson Science Associates. Jefferson Lab Director and JSA President Hugh Montgomery presented the award to Bertozzi during the annual Users Workshop and Meeting held in June

MIT Professor William Bertozzi, recognized as a world leader and innovator in the field of experimental electromagnetic nuclear physics, is the first recipient of the Outstanding Nuclear Physicist Award presented by Jefferson Science Associates.

Bertozzi received the award, which includes a $10,000 prize, during a special session at Jefferson Lab's annual Users Group Workshop and Meeting held in June.

"Bill's contributions to the nuclear physics program at Jefferson Lab are many … (ranging from) his leadership in the development of the use of electron scattering as a tool for the study of nuclear and nucleon structure and in the development of experimental techniques and novel instrumentation to carry out these measurements … (to) his mentoring of many of the most active members of the Jefferson Lab community as Ph.D. students and postdocs," wrote Lawrence Cardman, former Jefferson Lab associate director for experimental nuclear physics, in a letter supporting the nomination of Bertozzi for the award.

SURA President & CEO Jerry Draayer and CSC/ATG President Alan Weakley, the owner representatives on the JSA Board of Directors, applauded the selection panel's choice, noting Bertozzi's pioneering work in the field and career-long support for the physics being advanced at Jefferson Lab.

"In making an inaugural award, it is especially important to choose someone distinctive. Bill Bertozzi has had a long history of leadership in his work at Jefferson Lab. Yet what makes him so unique is evidenced in a letter he wrote in response to notification that he had been selected where he spoke of his ‘many brilliant graduate students, postdocs and colleagues at MIT and other universities along with the expert staff at Jefferson Lab.’” said JSA President and Jefferson Lab Director Hugh Montgomery. "I believe the selection panel was successful in its mission."

The selection panel included Thomas Appelquist, Yale University; John Hardy, Texas A&M; Robert McKeown, deputy director for Science and Technology, Jefferson Lab; Stephen Wallace, University of Maryland; and, Elizabeth Lawson, SURA chief governance officer and principal JSA/JLab liaison.

Bertozzi, a physics professor at MIT since 1968, is the principal investigator leading the Nuclear Interactions Group at the MIT Laboratory for Nuclear Science. In that capacity, he is engaged in investigating the structure of nucleons and nuclei using high-energy electrons and photons as probes.

During his career, he has been the recipient of many awards and fellowships, including the Mentoring Award from the American Physical Society (2008), the Shell Graduate Fellowship at MIT (1954-56), and fellowships with both the American Association for the Advancement of Science and the American Physical Society, and the Summer Internship Program at Brookhaven National Laboratory (1953).

After accepting the award on June 6, Bertozzi acknowledged and thanked Jefferson Science Associates and SURA, as well as the many colleagues, students, post docs and JLab staff he has worked with over the years. He presented a history of the lab's inception and development that he called "a marvelous adventure; and concluded saying, "JLab is now the world’s foremost facility for probing cold, strongly interacting systems at short distances." He and his students plan to use it for a longtime to come.

The Outstanding Nuclear Physicist Award is one of many projects supported by the JSA Initiatives Fund, a program funded by JSA owners (SURA and CSC) to support efforts that further the scientific outreach and promote the science, education and technology missions of Jefferson Lab and the lab's user community. The annual commitment is administered by the JSA Programs Committee. For more information, see http://www.jsallc.org/IF/IFIndex.html.

Editor's note: The briefing slides from Bertozzi's talk are available on the 2011 Users Group Workshop and Meeting agenda webpage at: http://www.jlab.org/conferences/ugm/program.html

In his youth, Bertozzi carried out an experiment in which he explored the relationship between the velocity of electrons and their kinetic energy by measurements over a range of accelerating voltages between 0.5 MeV and 15 MeV. The kinetic energy is measured using calorimetry and the velocity is measured by time-of-flight. This link (http://education.jlab.org/scienceseries/ultimate_speed.html) accesses an educational film, made in 1962, documenting the experiment and shows that the electrons have a limiting speed equal to that of light, in agreement with Einstein's theory of relativity. Click on the second link in the grey box to start the video.

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2010 Thesis Prize Winner Recognized at Users Meeting

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Xin Qian (center), California Institute of Technology, was awarded the 2010 JSA Thesis Prize during the Jefferson Lab annual Users Workshop and Meeting held in June. He accepted the award from Robert McKeown (left), JLab's deputy director for science, and Zein-Eddine Meziani, chairman of the Users Group Board of Directors, which issued the prize.

If Xin Qian had his way, all graduate students in experimental nuclear physics would get hands-on experience working with equipment. Qian, who has been awarded the 2010 Jefferson Science Associates Thesis Prize, credits his success to the hands-on experience he gained while working on his Ph.D. at Jefferson Lab.

"Nowadays, the experiments are becoming bigger and bigger, and a lot of students do not have the chance to work on hardware, but focus on analysis and simulation. In simulation, if anything goes wrong, you can just go back and redo it," Qian explained. "But when you work with hardware, if you make a wrong move, it will cost you a lot. So, I think those kinds of experiences are very precious."

In addition to working on the hardware before his Ph.D. experiment, Qian also had the opportunity to support the experiment by monitoring data taking during the experimental run.

"I worked very hard every day during the data taking. It was actually quite a fun and exciting experience to catch all the random problems that pop up during the run and to solve them on site," he said.

Qian was presented with the thesis prize at the 2011 Annual Users Workshop and Meeting, held at Jefferson Lab June 6-8. Qian earned his Ph.D. from Duke University in May 2010.

"After a lengthy but rigorous process of selection among an outstanding set of applications, Dr. Qian's thesis emerged as the favorite. Although, in the end, one winner had to be chosen, both committees reviewing the applications were impressed by the quality of the submitted theses," said Zein-Eddine Meziani, chairman of the Users Group Board of Directors, who issued the prize.

Qian's research was focused on filling in gaps in the scientific knowledge of the fine details of the building blocks of the nucleus, the so-called nucleons that are more commonly known as protons and neutrons. He and his colleagues were interested in the nucleon's constituents, called partons. To learn more about partons, the researchers measured the transverse momentum distributions of the nucleon.

"We are trying to understand the nucleon. The transverse momentum distributions are basically talking about the three-dimensional momentum space – how these partons move," Qian explained.

While other experimental efforts have measured the momentum inside the proton at high precision, Qian said this experiment is the first to offer a precision measurement of the quantity inside the neutron.

"These are the best neutron results in the world, a precision measurement in the valence region. We did a challenging experiment, and we did the best we can," he said. The results of this work have been accepted by Physical Review Letters.

Qian is currently a second-year Robert A. Millikan Postdoctoral Scholar at the California Institute of Technology, where he works on the Daya Bay Reactor Neutrino Experiment, based in China, and on R&D for Fermilab's proposed Long-Baseline Neutrino Experiment.

The Thesis Prize was established in 1999 by the Southeastern Universities Research Association, the predecessor management and operating contractor for Jefferson Lab. It is awarded for the best graduate student thesis related to Jefferson Lab research and includes an award of $2,000 and a commemorative plaque. Four areas are considered in rating a submitted thesis: the quality of the written dissertation, the student's contribution to the research, the work's impact on the field of physics and service (how the work benefits Jefferson Lab or other experiments).

The Thesis Prize is one of many projects supported by the JSA Initiatives Fund, a program funded by JSA owners (SURA and CSC) to support efforts that further the scientific outreach and promote the science, education and technology missions of Jefferson Lab and the lab's user community. The program is administered by the JSA Programs Committee. For more information, see http://www.jsallc.org/IF/IFIndex.html .

By Kandice Carter
Science writer

 

Young Researchers Win Poster Contest Prizes

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From left, clockwise: First place and a $1,000 prize went to Katherine Myers, George Washington University, with her poster titled: Aluminum Target Window Backgrounds in the Qweak Experiment.

Donald Jones (above), University of Virginia, won second place and $500 with his poster: Development
of a Compton Polarimeter for Hall C.

And in a tie, third place and the $250 prize was shared by James Maxwell, University of Virginia, and Navaphon Muangma,
MIT. Maxwell’s poster was titled: Spin Asymmetries of the Nucleon Experiment (E07-003) and Muangma’s poster was: E07-006 Nucleon-Nucleon Short-Range Correlations at the Repulsive Core Limit.

Jefferson Lab's annual users group meeting took place June 6-8, and included a variety of physics talks and experiment results and presentations from members of the Users Group Board of Directors, lab management and funding agencies. The group also took the time to recognize young scientists for their achievements, inaugurated a new senior scientist award and recognized JLab's Physics Division Associate Director Larry Cardman, for his years leading JLab's Physics Division, for his leadership and scientific accomplishments.

Among the many events and sessions, the graduate student poster, begun in 2005, continues to grow in interest and participation. This year, 16 young researchers participated in the poster competition. They discussed their work first with the judges during an evaluation period on June 6, and then stayed to share their posters and their work during the users meeting reception held that evening.

After the point cards had been tallied, first place and a $1,000 prize went to Katherine Myers, George Washington University, with her poster titled: Aluminum Target Window Backgrounds in the Qweak Experiment. Donald Jones, University of Virginia, won second place and $500 with his poster: Development of a Compton Polarimeter for Hall C. And in a tie, third place and the $250 prize was shared by James Maxwell, University of Virginia, and Navaphon Muangma, MIT. Maxwell's poster was titled: Spin Asymmetries of the Nucleon Experiment (E07-003) and Muangma's poster was: E07-006 Nucleon-Nucleon Short-Range Correlations at the Repulsive Core Limit.

Judges for the poster competition included Jian-Ping Chen, Jefferson Lab; Wouter Deconinck, The College of William and Mary; Eugene Pasyuk, Jefferson Lab; and Christian Weiss, Jefferson Lab.

At the end of the contest, in a joint statement, the judges said, "We were impressed by the quality of the posters. Mostly everyone did an excellent job of fielding questions and had a very good command of the material. It was exceedingly difficult to choose the top three. We were aware that the students were at varying levels in their graduate career and see a lot of promise. They should be encouraged to participate in future competitions."

The poster competition is funded through the JSA Initiatives Fund, a program provided annually by the owners of JSA to support programs, initiatives, and activities that further the scientific outreach, and promote the science, education and technology missions of Jefferson Lab and benefit the lab's user community.


Student Lays Groundwork for Scientific Career With Internship

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Intern Charles Forman prepares to make a cellulose acetate replica of the interior surface of a high-performing niobium accelerator cavity.  He is doing this so he can characterize the surface topography of the cavity, by using various types of microscopy

When Charles Forman returned to Jefferson Lab in May to begin his third summer as an intern, he did so as one of the U.S. Department of Energy's top interns.

Forman, who will begin his junior year at Virginia Tech this fall, took a second place earlier this year in an undergraduate research poster competition held at the AAAS (American Association for the Advancement of Science) annual meeting in Washington, D.C. He also was later recognized in the AAAS journal, Science.

Forman spent his first summer at Jefferson Lab in 2009 when he was a Warwick High School senior participating in the lab's high school summer honors internship program. This summer and last, he has interned at the lab as a Department of Energy Science Undergraduate Laboratory Intern, or SULI.

A materials science and engineering major, he is working on niobium cavities under Research Adviser Michael Kelley of Jefferson Lab and the College of William & Mary. Forman's work involves carrying out exacting tests and measurements on various surfaces inside a niobium cavity, which are critical components to Jefferson Lab's particle accelerator and other accelerators around the world.

The problem driving his work is that some accelerator cavities perform poorly due to internal-surface micro-roughness; and it is unclear which topographical features have the most impact on performance. Forman's cutting-edge research is the first to slice open a high-performing cavity in order to discover and document tolerable surface features. This information is critical for identifying harmful defects. For his research, Forman made replicas of the cavity's interior surface and characterized the surface topography using optical and scanning electron microscopes.

Last year, Forman presented his SULI research (Superconducting Radiofrequency Accelerator Cavity: Examination of the Interior Surface) at the Virginia Tech ACerS (American Ceramic Society) Speaking Contest and won first place. The following month, he went to the national semifinals at the 2011 MS&T (Materials Science & Technology) Conference in Houston, Texas.
Out of nearly 500 SULI students from across the country, Forman's research was one of 14 papers selected for publication in the DOE Journal of Undergraduate Research Volume X. As a result, he was invited to participate in the annual nationwide, undergraduate research poster competition held at the AAAS annual meeting in February, where he took second place.

In April, Forman presented his work at the annual Virginia Tech Undergraduate Research and Prospective Graduate Student Conference.

"I didn't know what to expect when I first came here for the high school internship," he recalls. "Chris Blazey, my high school physics teacher, strongly recommended that I apply for one of JLab's internships. My older brother, James, also had work experience at Jefferson Lab and suggested that I apply for an internship. At the time, I was interested in electrical engineering, and that first summer I worked with John Musson to improve the design of piezotuner power supplies. It is very satisfying knowing that my summer project contributed to the upcoming 12 GeV Upgrade as 80 of these power supplies will eventually be installed in the accelerator."

That experience opened Forman's eyes to other research opportunities and programs at the lab. Once in college he applied for and received a SULI internship.

"Dr. Kelley emailed me before the program started last year and laid out the basics of a research project. He asked if this was work I'd be interested in doing," Forman recounts. "I decided to accept his research proposal and I am constantly reminded that this was a worthwhile decision. The project and work experience greatly helped me throughout the school year.

"For instance," he notes, "in research, there are two separate and equally-difficult tasks: solving the problems associated with the scientific method and effectively communicating the project in a concise research paper. Working at JLab, I quickly learned that many problems in research have an infinite number of solutions. With Dr. Kelley's help, I am learning how to work through open-ended problems in my project as well as in my developing research paper."

Another benefit of his experience has been learning how to use the equipment needed for his research and carrying out the various tests that are part of his project. "It was rewarding to already have real-world knowledge and experience with microscopy before entering my materials laboratory class at Virginia Tech," he adds. "I’ve gained experience using sophisticated equipment at JLab, such as scanning electron microscopes, that students generally don't have direct access to at school.

"This year I'm continuing my research from last summer – hoping to gain more depth by measuring surface features using atomic force microscopy," he says.

"Every day I am impressed by the helpfulness and intelligence of the people in the JLab community," Forman concludes. "I'm grateful for this experience and I hope to find a profession in a comparable working environment."

He is the son of Peter and Marilyn Forman, Newport News.


Lab Community Invited to Summer Intern Poster Session

Thirty high school and college students, who participated in summer science internship programs at Jefferson Lab, will share their experiences and projects during a poster session on Friday, July 29, from 11:45 a.m. to 1:30 p.m. in the CEBAF Center lobby. The JLab community is invited to the poster session.

The six participants of the High School Summer Honors Program, and 24 participants representing the Science Undergraduate Laboratory Internship and Old Dominion University Research Experiences for Undergraduates programs, will present posters they developed based on their work or research projects.

Many of the interns are from the Hampton Roads area. Some of the students are here for their second or third summer. These students plan to pursue careers in science or technology. Their respective projects at Jefferson Lab directly involved them in the culture, activities and science of a U.S. Department of Energy national laboratory, including accelerator engineering, experimental research, free-electron laser projects and computer programming.

"Come out and talk with the students and view their posters," urges Jan Tyler, Science Education manager and summer interns coordinator. "These bright, energetic young people have been involved in a variety of projects. They've done some outstanding work. Giving them the opportunity to talk about that work with the lab community is good for them and gives us the opportunity to acknowledge their work and thank them for their contributions to the lab."


Walls Came Tumbling Down…a Recycling Success Story

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The blocks, dubbed "stonehenge" by some, were originally part of the shielding used in Building 58 – when it was NASA's Space Radiation Effects Laboratory – long before it became JLab's Test Lab. The assembly of blocks measured about 70 feet long by 52 feet wide and ranged between 15 and 27 feet high.

In the end, more than 1,802 tons of broken up blocks were hauled away for recycling – to be used as construction fill material for projects like road beds.

For years the imposing stack of concrete blocks sat, tightly and neatly arranged, behind the line of trees just east of the Test Lab. So long had the monoliths sat there that saplings and grass grew from seams between some of the massive blocks. Most people passed by the building-sized assemblage daily – never giving it a second glance or knowing that the blocks were remnants from a NASA research facility that preceded Jefferson Lab.

Over the last decade, Jefferson Lab's Facilities Management & Logistics staff and Radiation Control staff studied and evaluated several ideas and proposals to appropriately dispose of the concrete "stonehenge" – one of the nicknames it acquired over the years. And this summer they succeeded. In the end, more than 1,802 tons of broken up blocks were hauled away for recycling – to be used as construction fill material.

The 135 concrete blocks, with a total weight of about 2,000 tons, were originally part of the shielding used in Building 58 – when it was NASA's Space Radiation Effects Laboratory (SREL) – long before it became JLab's Test Lab. The blocks, ranging in weight from 1 ton to nearly 45 tons, were removed from the building and placed outdoors when the NASA facility was decommissioned around 1980. Jefferson Lab – then CEBAF – took over the site in the mid-1980s.

FM&L Structural Engineer Suresh Chandra knows the blocks well – their sizes, weights and contours. Chandra designed the arrangement that they had sat in since 1989; and he oversaw a subcontractor in the assembly of that configuration, which measured about 70 feet long by 52 feet wide and ranged between 15 and 27 feet high.

Many of the steel-reinforced blocks were slightly radioactive (activated) after years of exposure to synchrotron radiation from NASA's SREL. Efforts to dispose of them had been stymied by high cost. At one time, Jefferson Lab received estimates of several million dollars for shipping the blocks to and burying them at a radioactive waste disposal site. So, the decision was made to hold them here until less costly disposal options could be identified.

Several factors came together to finally allow for the blocks' disposal. Primarily, the blocks had sat long enough for the radioactivity to decay. In the 30 years since the blocks had been removed from the building, the main radionuclide of concern – sodium-22 (Na-22), with a half-life of 2.6 years – had been through more than 11 half-lives, rendering it effectively gone, according to RadCon’s Keith Welch.

Some other longer-lived nuclides were present in some of the blocks because of the high-density metallic-ore content of those blocks (primarily cobalt-60 (Co-60), with a half-life of 5.27 years). Those nuclides were responsible for the detectable activity in the handful of blocks that JLab is continuing to keep.

Over the last few years, the Department of Energy provided Jefferson Lab, and the other DOE research facilities, with clarification on administrative restrictions that are part of the "metals moratorium" and "recycling suspension." Also during this time, JLab's RadCon group enhanced its technical capabilities and documentation regarding the lab's clearance process for these types of materials.

"The combination of radioactive decay over the decades, together with DOE's clarification of release restrictions and our demonstration of having robust clearance methods provided a path forward to release most of the blocks as clean," Welch noted.

RadCon conducted in situ screening surveys of the blocks. These surveys indicated a high likelihood that most of the blocks could be cleared for release with no restrictions. Meanwhile, Chandra was researching how to cost effectively dispose of or recycle the concrete blocks. Two companies submitted bids to break up the blocks and haul the material off for recycling.

"We appreciate all the work RadCon did in surveying the blocks and helping us to categorize them," said Rusty Sprouse, FM&L director. "There was some concern, but the entire process went very smoothly. It was a coordinated effort on the part of several groups, including RadCon, Industrial Hygiene, Accelerator Division and Facilities Management."

To keep costs down, FM&L had the blocks pushed off the structure (instead of lifted up). Once on the ground, they were broken into smaller pieces where they sat. The subcontractor for the job was Waste Alliance, LLC, which subcontracted the job to S.B. Cox, out of Richmond. S.B. Cox used a track hoe to push the blocks down and two track hoes with rams (hydraulic hammers) to break up the steel-reinforced concrete blocks. Then the track hoe with the bucket loaded the pieces into a dump truck and the material was hauled to a recycling facility in Yorktown. It will be used as construction fill for projects like filling in road beds.

After sections of the blocks came tumbling down, the track hoe operator carefully rotated each block so RadCon technicians could perform a meticulous radiological survey on all six faces of every block. By the completion of the project only six blocks had been identified as still slightly activated (reading above background). Three of these were already known to be active, and a fourth was suspected – from historical surveys and the pre-screening by RadCon. Those remaining blocks have been moved to JLab's Central Material Storage Area, and will be the subject of an effort to dispose of them under a DOE "authorized limit" process.

A project that had been estimated to cost millions a decade ago was completed in mid-June for about $100,000, Chandra noted.

The area where the blocks stood has been cleared and will be graveled. In the near term it will be used for parking by construction workers on the Technology and Engineering Development Facility project. After TEDF project completion in 2013, the parking lot will be returned to JLab and used by TEDF occupants.


Congratulations to Recent Award Recipients

The inaugural Ken Wilson Lattice Award for an important contribution to lattice field theory in the last three years has been awarded to a paper by Dru Renner, now a member of JLab's Theory Center; Xu Feng, now at KEK, Japan; Karl Jansen, DESY, Germany; and Marcus Petschlies, Institut für Physik, Humboldt-Universität, Germany. The award was presented on July 12 at the 29th International Symposium on Lattice Field Theory. The paper titled "Two-flavor QCD correction to lepton magnetic moments at leading-order in the electromagnetic coupling" is at: http://arxiv.org/abs/1103.4818

Kelly Dixon, Cryogenics group, was awarded this year's George T. Mulholland Award for Excellence in Cryogenic Engineering from the Cryogenic Society of America. The CSA awards were presented at a banquet in Spokane, Wash., on June 16. The award is given for notable engineering development in a particular area leading to a major contribution in the cryogenic field, i.e, markedly increasing cryocooler efficiency, developing a novel cryogenic system for fusion applications, improving biomedicine by using cryogenics, etc.

Adam Sarty, a member of Jefferson Lab's Users group and a physics professor at Saint Mary's University, Nova Scotia, has received a $3 million National Teaching Fellowship – the highest teaching honor in Canada. Sarty was presented the fellowship at the annual Society for Teaching and Learning in Higher Education conference at the University of Saskatchewan in June.

Check out future editions of On Target for stories about these and other members of the JLab community – making their mark on science and technology.


Lab Earns Environmental Stewardship Award

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Jefferson Lab was recently recognized for its environmental stewardship. The lab was among the businesses, industries and agencies earning a 2010 Hampton Roads Sanitation District Pretreatment Excellence Gold Award.

Gold awards are presented to businesses that maintained perfect industrial wastewater permit compliance for a full compliance year (calendar year 2010).

The Hampton Roads Sanitation District held its annual awards luncheon on May 5 in Portsmouth. During the event, HRSD recognized the award recipients for their exemplary permit compliance and for their outstanding pollution prevention measures.

The lab also received a Pollution Prevention Partnership citation for its recycling efforts – for incorporating used shielding blocks into Hall D.

An open letter from HRSD reads, in part: "Congratulations … for exemplary permit compliance and outstanding pollution prevention measures. These businesses pretreat their industrial wastewater before discharging it to HRSD's system. Their efforts help protect our waterways and other natural resources."

This recognition is a reflection of the Jefferson Lab community's execution of our Environmental Management System, according to Bill Rainey, JLab's Environmental Program manager. "One of the major EMS objectives is to efficiently manage the lab's environmental compliance program. These awards indicate we are meeting that objective," he said.

Rainey attended the May 5 awards event to accept the award for the lab.

Contact Rainey, ext. 7898, or email wrainey@jlab.org, with information regarding any pollution prevention improvements underway in 2011 that could qualify for an HRSD or other award or recognition.

HRSD serves a population of 1.6 million in 17 cities and counties in southeastern Virginia. Its 13 treatment plants can handle up to 249 million gallons of wastewater every day.


Lab's YouTube Channel Surpasses 1M Views

The laboratory's Science Education group hosts a JLab YouTube channel that features more than 130 educational or informational videos. At the end of May, the channel reached the first of two milestones, according to Steve Gagnon, Science Education technician and webmaster.

On May 29, the lab's YouTube channel recorded its 1 millionth video view. That's a combined total of views for the Frostbite Theater collection, the 80 or so Science Series videos, the JLab introductory video and a few other lab videos. Then, on June 2, the Frostbite Theater collection hit the million views mark.

The Frostbite Theater vignettes – a collaborative effort between Science Education and Public Affairs – features liquid nitrogen demonstrations and other science activities.

"A number of the experiments have come directly from our Physics Fest presentation," said Gagnon. "But, the nice thing about these videos is that we've been able to expand our reach and do things that we'd never be able to do with a live audience. We're also able to interact with the viewers on YouTube through their comments section. It's another way we can reach out to students."

Among the international research laboratories, CERN's YouTube channel views outpace everyone else – with 3 million views and counting. But among the U.S. DOE research facilities, JLab's YouTube view numbers are outpacing its sister labs.

JLab's YouTube page is at: http://www.youtube.com/JeffersonLab/


Engineering Announces Special Cryo Seminars

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Two special cryogenics seminars will take place at Jefferson Lab in August. The seminars, scheduled for Aug. 4 and 16, are part of the Engineering Division's Professional Development Program.

These special-topic seminars, being presented by Peter Knudsen, will address recent developments in cryogenics with significant implications in supporting technologies for the national science agenda. The Aug. 4 seminar is titled: Cold End Process Options for Nominal 2 Kelvin Efficiency Improvements; and the Aug. 16 talk is titled: JLab's 12 GeV Compressor System and Development Work. Each event will take place from 1:30 – 3 p.m. in the CEBAF Center auditorium.

JLab engineers, technicians and interested employees are invited to attend these presentations. Engineers from local industry and graduate engineering students enrolled in local universities may also attend.

Early this year, the Engineering Division established a professional development program in order to build on the technical knowledge and skill set of the lab's engineering and technical staff. The program was kicked off on Jan. 25 with a series of seminars devoted to cryogenics and presented by members of the lab's award-winning cryogenics staff: Rao Ganni, Jonathan Creel, Peter Knudsen, Mathew Wright and Dana Arenius.

No advance registration is needed for these events. And no Continuing Education Units will be granted for these two talks.

For additional information regarding these talks, please see the Cryogenics Seminars poster. General inquiries about these seminars or the Engineering Division's Professional Development Program may be directed to Gayle Coleman, via email sundeen@jlab.org or by calling 269-7712.


Pushing the Limits with High-Voltage Electron Guns (ILC NewsLine story)

The July 21 issue of ILC NewsLine reports on Jefferson Lab's Injector group exploring new designs for spin-polarised photoelectron guns. Check out the story by Fermilab's Christine Herman at: http://newsline.linearcollider.org/2011/07/21/pushing-the-limits-with-high-voltage-electron-guns/


DOE Sponsors Food Drive Through Aug. 5

The Department of Energy is participating in the "Feds Feed Families" food drive this year. The DOE encourages its federal employees to volunteer by collecting much-needed food for those in need. The overall federal goal is 2 million pounds of food nationwide, with DOE’s goal 132,000 pounds. At JLab, the Thomas Jefferson Site Office has invited lab employees to participate in the food drive benefiting the Virginia Peninsula Food Bank.

If interested, items needed include: canned meats (fish, ham, chicken, beef stew, etc.), canned fruits and vegetables, complete meals (boxed meals, pasta and sauce, mac and cheese, etc.), boxed cereals, rice, granola bars, peanut butter, and hygiene products (shampoo, tooth paste, deodorant, soap, diapers). Please don't bring items in glass containers.

Anyone wishing to participate may place any of the above items or other non-perishables in the marked barrels located in the CEBAF Center lobby anytime from July 25 through Aug. 5.

For more information on Feds Feed Families, visit the website at:

www.fedsfeedfamilies.gov or contact Steve Neilson at ext. 7215.


JLab Scrapbook

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Sharing Science & a Cool Treat Beats the Heat!

 

Jefferson Lab Director Hugh Montgomery sat down for lunch on July 7 with the Science Undergraduate Laboratory Internship and the Research Experiences for Undergraduate interns. They discussed wide ranging topics – from the federal government budget's impact on scientific research and current research projects to personal insights. Bringing the lunch to a "cool" end, Montgomery and REU intern Brian Josey donned safety gear (goggles and gloves) and whipped up a frosty batch of Liquid Nitrogen Ice Cream. Montgomery cranked out the vanilla while Josey stirred the chocolate. At appropriate intervals, Lisa Surles-Law, Science Education, added liquid nitrogen to the cream mixture. Montgomery and the interns enjoyed the frosty outcome.

Information about the Department of Energy's SULI program is available at: http://science.energy.gov/wdts/suli/

Information about the National Science Foundation's REU program is available at: http://www.nsf.gov/crssprgm/reu/

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JAG Dog Training Club Graduates Fourth Class of Therapy Dogs

The Jefferson Lab Activities Group Dog Training Club graduated its fourth class of therapy dogs on June 28. The 2011 graduating class includes, from left to right, Joyce Miller, PG and Sammy (greyhounds), Angel Bruhwel, Hope (American foxhound), Scott Bruhwel, Indy (hound mix), Kim Young, Nikko (Samoyed), Dan Young, Tally (Samoyed), Eddie (French bulldog), Jamie (boxer), Ingrid Kross, Brian Kross, Loki (boxer), Cleo (boxer), Shadow (Yorkshire terrier), and Jennifer Monaghan. Photo by Alan Gavalya, Physics Division. Information about the club is available on the JAG webpage at: http://www.jlab.org/intralab/committees/jag/JAG%20Activites/Activities.html

The On Target newsletter is published monthly by the Thomas Jefferson National Accelerator Facility (Jefferson Lab), a nuclear physics research laboratory in Newport News, Virginia, operated by Jefferson Science Associates, LLC, for the U.S. Department of Energy's Office of Science. Possible news items and ideas for future stories may be emailed to jlabinfo@jlab.org, or sent to the Jefferson Lab Public Affairs Office, Suite 15, 12000 Jefferson Avenue, Newport News, VA 23606