Jarvis Caffrey, a Ph.D. candidate in nuclear engineering, spent the summer interning at NASA’s Marshall Space Flight Center in Huntsville, Alabama.

Under the direction of NASA Astrophysicist Peter Bertone and Prof. David Hamby, Caffrey is investigating one of the major challenges facing long-term space flight outside of Earth’s magnetic field.

“Astronauts are exposed to higher radiation doses outside the magnetic field of earth; on longer missions they could exceed what is considered the lifetime dose limit,” Caffrey said.

Because there are heavier particles in space that can interact with DNA, they can create more concentrated regions of damage and cause what’s called a double strand break or DSB. Research on DSBs by M. Cristina Negritto, Ph.D. and Peter Aplan, M.D. indicate that although

the body has mechanisms to repair a DSB in a cell, if repaired incorrectly there can be deletions, translocations, and fusions in the DNA. These features are often found in cancerous cells.

“The majority of radiation dose during exploratory space missions takes place in this heavy particle environment,” Caffrey said, putting astronauts’ cells at increased risk for cancer formation.

Caffrey’s work explores a modification to a radiation detection device already used in space travel.

“The microdosimeter is considered the gold standard for this type of detection,” Caffrey said. “It simulates a single cell nucleus but is built large enough to record these interactions more frequently. But microdosimeters do have limits. They register any particle interacting with it regardless of whether

it was a glancing pass or a direct hit. This skews the data and makes it difficult to accurately calculate risk. Microdosimeters also cannot distinguish between particles.”

Caffrey is working on a way to determine the detection location and modify the microdosimeter’s measurement to correct for this new information. He’s building a hybrid detector with a gas center and a scintillating wall to sense the position of each particle interaction. By knowing the particle type and location of interaction with the model cell, the

NEUTRONTHE

Traditional Approach:

Assume mean chord length for all events in isotropic flux:

FALL 2013

Nuclear Engineering & Radiation Health Physics

PARTICLE TRACKING IMPROVEMENTS FOR COSMIC RAY MICRODOSIMETERS JARVIS CAFFREY, PHD CANDIDATE

Fall 2013.indd 1 12/3/2013 3:31:45 PM

Nuclear Engineering & Radiation Health Physics

hybrid detector would be able to adjust the dose and risk assessments to a more accurate value.

Caffrey thinks current dosimeters are likely overestimating dose, thanks to excess energy contributions from particles passing through the detector wall. The hope is that this more accurate measurement will lead to a more advanced understanding of radiation dose and the space environment.

As an engineering major, it’s hard for many students to find enough time between class and loads of homework to be active in the college community.

Health physics undergraduate student Kristen Tremaine has managed to achieve a difficult balance between the sport she loves and her chosen career path.

“Being an engineering major while participating in extracurricular activities has made me a much more organized and driven person. Polo can take 20+ hours of commitment a week (between feeding the horses, practicing, traveling, doing stalls, participating in fund raising, etc.), so it really takes organization to stay on top of all your schoolwork,” Tremaine said.

According to the National Survey of Student Engagement, which Oregon State participates in, engineering

CAFFREY CONTINUED

FY 2013 DATA$6 M RESEARCH EXPENDITURES$550,333.84 per tenure & tenure-track faculty member avg.

2 NEW FACULTY MEMBERS25 new faculty hires college-wide

11 TT&T FACULTY MEMBERSAcross nuclear engineering, health physics and medical physics

325 ENROLLED STUDENTS 109 graduate, 216 undergraduate

29-1 STUDENTS TO FACULTY

UPCOMING EVENTS

4TH ANNUAL WINTER CONFERENCESaturday Jan 18 20149:00 am -3:30 pmRichardson Hall rooms 107 & 115Abstracts due by December 20thPlease email them to neumant@onid.orst.edu with a subject line (winter conference abstract)All students are welcome and encouraged to present anything related to the nuclear world.Abstract 1-3 pages submitted in pdf format.

BEACH PARTY/ANNUAL RECOGNITION DINNERTuesday January 21 TBDJoin NERHP faculty, staff, and students for a beach party in the dead of winter (indoors of course). We’ll recognize ANS Winter Conference awardees and student volunteers. Dinner and fun provided.

YOUNG ALUMNUS EARNS EXCELLENCE AWARDFROM AMERICAN NUCLEAR SOCIETY YOUNG MEMBERS GROUP

This article was reprinted with permission from the American Nuclear Society Young Members Group.

students spend 20 hours per week preparing for classes, the highest of all academic categories. It’s a demanding yet growing major, approximately one in four Oregon State students are engineering majors.

“I believe that engineering is a field that you really commit to as a student,” she said. “I love that the classes and labs I have taken at Oregon State have really immersed me into the College of Engineering because I know that this has given me the dedication to my education. Working as a College of Engineering Ambassador has also allowed me to feel connected to my major.”

Tremaine will graduate this spring with an honors bachelor of science in radiation health physics and public health with a health management and policy option.

network with other alumni and industry pros Department of Nuclear Engineering and Radiation Health Physics on LinkedIn Follow the link on the homepage of ne.oregonstate.edu to join the group

The Young Member Excellence Award recognizes “a young member who has demonstrated overall excellence in a variety of areas.” It is granted to an actively involved ANS YMG member who “advances the goals of the ANS YMG, displays outstanding non-technical skills as well as technical or managerial ability, is recognized by others in their field, demonstrates high quality and safety standards, and positively represents nuclear science and technology to the general population.”

This year, YMG is delighted to announce that Dr. Piyush Sabharwall is the recipient of the 2013 Young Member Excellence Award.

Dr. Sabharwall is a staff research scientist working in the Thermal Hydraulics and Reactor Safety Division under Nuclear System Design and Analysis Division Idaho National Laboratory (INL).

His recent work has focused on developing and optimizing a heat exchanger for the next generation of gas- and fluoride-cooled reactors, and on developing a method for validating computational fluid dynamic safety codes using the Matched Index of Refraction (MIR) facility at INL. The uncertainty quantification method developed in this study will lead to high quality MIR data with accurate and reliable uncertainty quantification, a valuable asset in validating advanced computational methods.

Dr. Sabharwall earned his undergraduate degree in mechanical engineering from Wilkes University in Pennsylvania, and his master’s degree in nuclear engineering with a minor in mechanical engineering from Oregon State University (OSU). Finally, he received a fission fusion INL research scholarship with which he pursued his Ph.D. in nuclear engineering at the University of Idaho.

As an active member of the Idaho Section of the American Nuclear Society and the Idaho Section of the American Society of Mechanical Engineers, Dr. Sabharwall helps educate the public and promote nuclear energy by participating in educational and community fairs.

FINDING THE BALANCE OF LIFE KRISTEN TREMAINE JUGGLES SCHOOL AND POLO CLUB Her post-graduation plans include

applying to medical school to pursue a career as a family practitioner or pediatric oncologist.

Although Tremaine’s future plans look to be just as demanding as her time in college, she wants to continue playing polo.

“I plan to play polo for the rest of my life (at least until I am no longer physically capable). I have fallen in love with the sport and with the community that I have connected to through the sport. I have already had the chance to play all over the West coast through the extended polo community, and I can’t wait to play internationally and throughout the United States,” she said.

The Oregon State Polo Club is the oldest recreational sports club at the university. Originally founded in 1923 as a military club, the organization experienced varying levels of activity until it was reestablished in 1966.

The horses are a combination of private donations and university owned stock. Although the team does travel for competition, the horses do not. The away team is provided horses by the home team, in order to cut down on travel cost.

Oregon State’s team has approximately 30 members that make up men’s varsity, women’s varsity, and coed junior varsity squads.

Kristen Tremaine, health physics major and member of the Oregon State Polo Club, works with one of the team’s horses. Tremaine strives to balance two very demanding aspects of her student life to succeed both in and out of the classroom. - Courtesy of Polo Club

Dr. Sabharwall was involved in the secondary heat exchanger (SHX) design for the molten salt cooled Advanced High Temperature Reactor. The SHX provides the interface between the intermediate coolant and the power conversion system or process application.

The identification of a viable SHX concept is based on the options for the power conversion scheme or the process heat application design needs. While the IHX serves as the primary coolant boundary, the SHX also serves as the coolant boundary and must be constructed to maintain system integrity under normal, offnormal, and accident conditions. The difference in pressure required in the power-conversion system and process heat applications imposes stringent requirements on the heat exchanger design.

He was also involved in design and development of two-phase thermosyphon in order to transport thermal energy from the reactor to chemical industrial plant, almost isothermally (i.e. with negligible temperature loss).

Currently he is leading the development of chemical heat pump for temperature amplification for nuclear hybrid energy systems and current fleet of light water reactors (LWRs). Dr. Sabharwall also serves as a co-principal investigator for engineered zircaloy cladding modification for improved accident tolerant fuel for LWRs. The modification of the surface should prove to be sustainable at higher temperatures and under high neutron fluence.

Fall 2013.indd 2-3 12/3/2013 3:31:52 PM

The Neutron is written and produced by Casey Mills, Public Information Representative II, Oregon State University Department of Nuclear Engineering and Radiation Health Physics. Casey.Mills@OregonState.edu, 541-737-2644.

Department of Nuclear Engineering & Radiation Health PhysicsOregon State University3451 SW Jefferson WayCorvallis, OR 97331541-737-2343

OregOn State radiatiOn HealtH PHySicS OnlineEarn your MHP or MS in Radiation Health Physics online from one of the top programs in the nation. Visit our website to learn more.

ecampus.oregonstate.edu/rhp13 | 800-667-1465

Fall 2013.indd 4 12/3/2013 3:31:58 PM