LANL: Physics Flash April 2011 - Los Alamos National Laboratory

I N S I D E 

2 Qu a n t u m c r y p t o g r a p h y 

a d va n c e s f o r c o m m u n i c a- 

t i o n s a n d t r a n s m i s s i o n 

s e c u r i t y 

3 me a s u r e m e n t o f t h e 

p u l s e d m a g n e t i c f i e l d 

t h r e s h o l d f o r t h e r m a l 

p l a s m a f o r m at i o n 

4 ex t r e m e fl u i d s te a m 

j o i n s lanl’s n e w ce n t e r 

o f mixing un d e r ex t r e m e 

co n d i t i o n s 

5 gr o w t h o f d e f e c t s o n 

i n e r t i a l c o n f i n e m e n t f u- 

s i o n c a p s u l e s 

6 fi r s t Z b o s o n s e v e r p r o- 

d u c e d a n d r e c o n s t r u c t e d 

in h e av y i o n c o l l i s i o n s 

7 fi r s t n e u t r o n i m a g e 

c o l l e c t e d at t h e nat i o n a l 

ig n i t i o n facility 

8 he a d s up! 

John George and 

Chad Olinger 

(far right); P-21’s 

deputy group 

leaders. 

Dueling Deps 

by Robb Kramer 

ADEPS Communications 

April 2011 

Main street, P-21, high noon. John “MRI” George squints into the bright sun. Down the way, past the 

Barnes Science Emporium, Chad “diagnostics” Olinger flexes his scroll-wheel finger and stares back. 

It’s come to this. Five, six . . . ten steps and the two deputies square off. 

“Someone’s gotta go,” George grumbles. 

“Lunch?” Olinger remarks. 

“Good thinking. We’ve got proposals to review.” 

The two amble off to the Otowi Steak House in this fictitious high-plains conurbation of Applied 

Modern Physics (P-21). 

Dueling deputies? Maybe not. 

Applied Modern Physics has a lot of territory and plenty of room for two deputy group leaders. In fact, 

it’s a necessity. In fact, there’s so much work to go around that these two not-so dueling deps work 

as partners. 

Chad Olinger has worked at Los Alamos for 26 years, starting as a postdoctoral 

researcher with Isotope Geochemistry, INC-7. As a 

deputy group leader, he supports management and 

leadership issues across the group. His technical 

contributions involve close work with the weapons 

analysis team in prompt diagnostic of historical 

underground nuclear tests and as a project leader 

for nuclear and non-nuclear data for the Advanced 

Simulation and Computing (ASC) program. “In this 

role,” Olinger said, “I coordinate with X Division 

program management to support radiochemistry and 

radiography as well as prompt diagnostics.” 

John George has served as a P-21 deputy 

group leader for a little more than a 

year and manages between a third 

and a half of an approximately 

50-person group. His 

responsibilities include program 

development, budgets, personnel 

and performance management, 

approvals, mentoring, responding 

to innumerable requests for data, 

and demonstration of compliance 

continued on page 2 

Los Alamos National Laboratory • Est. 1943 Physics Flash—Newsletter of the Physics Division

Deps . . . with policy. George’s technical contribution includes 

leading two Laboratory Directed Research and Development 

(LDRD) projects, “Synthetic Cognition through Petascale Models of 

Primate Visual Cortex” and “Probing Brain Dynamics by Ultra-Low 

Field MRI,” as well as an LDRD-Exploratory Research project on 

the development of high density brain interface employing an array 

of novel sensors that detect individual nerve cells (in collaboration 

with Shadi Dayeh, Tom Picraux, Andrew Dattelbaum and others in 

MPA-CINT), serving on a DOE project to build an artificial retina, 

and leading a DARPA “Neovision” project to develop computer 

systems that mimic visual processing in the brain. “Altogether,” he 

said, “it fills up my days and much of my nights.” 

OK, but what about the duel? 

Two deputy group leaders? 

George explained P-21’s management architecture. “There are 

some good, practical reasons for this arrangement, stemming 

from the variable but substantial administrative and managerial 

workload.” The diversity of both staff and projects—from 

ultrasensitive measurement technology and applications 

(the SQUID team), to brain imaging and modeling, quantum 

communication, and weapons radiography and test analysis— 

creates a “variable and substantial administrative and managerial 

workload.” Olinger echoed this assessment: “Our functions are 

different in that our technical focuses are on different aspects of the 

group, but beyond that we split leadership duties broadly.” Because 

their technical backgrounds are so different, there has not been 

significant technical collaboration between the two deputies, but 

they do support each other in activities such as reviewing proposals 

to ensure that they can be understood by general reviewers. 

Duality 

“Clearly,” George said, “we are dual-ing, but I don’t consider it a 

blood sport! We have a good working relationship.” Olinger agreed. 

“We have worked well together from day one. There really is no 

reason for us to ‘duel’ in that our technical work is so different. Even 

if working for the same funding sources, both of our styles are more 

collaborative than competitive. On the leadership and management 

side we both share duties to a reasonable, level load.” 

Goals 

As ‘dualing’ deputies, George and Olinger have specific goals for 

P-21. Olinger focuses on team collaborations: “My largest goal in 

prompt diagnostics is to ensure that P-21 and P-23 work toward 

an integrated team concept. Although we are in different groups, 

both teams can benefit from the other’s technical responsibilities.” 

Olinger also has a goal that most team members from each group 

will be able to support analyses in the other group. Such cross 

training will enhance the ability to take full scientific advantage of 

the complementary diagnostics and will make both teams more 

robust against attrition issues. 

George looks to the marketplace and Physics Division’s role in 

being competitive: “Our group has a hand in a number of state-ofthe-art 

imaging, analysis and modeling techniques that can have 

a significant impact on other projects across the Division and the 

Lab.” He described P-21’s entrepreneurial staff and a substantial 

portfolio of work for nontraditional sponsors. “I think we can help P 

Division become more agile and more competitive in the broader 

research marketplace,” he mused. P-21 is poised on the edge 

of a scientific revolution that will redefine the understanding of 

intelligence. “We are,” George explained, “uniquely positioned to 

push back the frontiers through development of new neuroimaging 

technologies, experimental and computational modeling 

studies, and development of systems that exploit our emerging 

understanding of neural computation.” 

The sun hangs bright over the high-plains. P-21 thrives under 

the watchful eyes of its dual deps, a critical and successful 

collaboration. 

Quantum cryptography 

advances for 

communications and 

transmission security 

In today’s technological world, the information passed through 

optical fiber networks every second is as valuable as currency. 

Often the security is not adequate for the growing network 

capabilities and the threats against them. 

Jane Nordholt, Richard Hughes, Charles Peterson, and Raymond 

T. Newell (P-21) have developed two unique cyber security 

technologies based on quantum key distribution that can provide 

both communications and transmission security. While fully capable 

of operating independently, these technologies can also operate as 


2 Physics Flash—Newsletter of the Physics Division

Quantum . . . one complete system for encryption and 

authentication. Quantum enabled security (QES) provides the 

transmission security, and quantum smart card (QKarD) provides 

the communications security. 

The new technologies represent a paradigm shift in practical 

cryptography. Unlike current cryptography techniques, which rely 

on the difficulty of mathematical problems to generate security, 

quantum encryption techniques rely on the laws of quantum 

mechanics. By placing cryptography on the solid foundations of 

physical laws, QKD provides encryption that is provably secure, not 

probably-secure. 

Quantum enabled security is a new cyber security capability using 

quantum (single photon) communications integrated with optical 

communications to provide a strong, innate security foundation 

at the photonic layer for optical fiber networks. QES provides 

unbreakable security to any digital data traversing a fiber optic 

network. Data is encrypted at the source using quantum-generated 

cryptographic keys. The laws of physics ensure that successful 

decryption can only take place at the authorized receiver. This 

technique is readily extensible over large networks, and it is 

backwards-compatible with existing transparent optical networks. 

Schematic of quantum enabled security in use. 

The Quantum Smart Card is a hand-held device and supporting 

network tools to provide individuals with quantum-generated 

cryptographic keys on the go. With a personalized set of quantum 

keys held in secure memory, a QKarD holder could encrypt 

telephone calls, text messages, or e-commerce transactions. Any 

digital transfer can be protected from eavesdropping. 

LANL has filed two separate patents for intellectual property related 

to the secure quantum communications, and a call for technology 

commercialization partners has been announced. (www.lanl.gov/ 

partnerships/license/techs/cybertechs.shtml). LDRD Reserve, 

Physics Division Royalty, Tech Transfer Technology Maturation, 

and other government agencies funded different aspects of the 

research. The work supports the Laboratory’s Global Security 

mission area and the Information Science and Technology and the 

Science of Signatures capability pillars. 

Technical contact: Beth Nordholt 

Technology Transfer contact: Marcus Lucero 

Measurement of the pulsed 

magnetic field threshold for 

thermal plasma formation 

Thomas Awe recently joined Plasma Physics (P-24) as a 

postdoctoral researcher. He and Principal Investigator Scott Hsu 

(P-24) are developing the Plasma Liner Experiment for the DOE 

Office of Fusion Energy Sciences. Awe gave an invited talk at the 

American Physical Society-Division of Plasma Physics Meeting 

describing his thesis work. The research is summarized in the 

following paragraphs. 

An important basic science question is what state of matter is 

created from a metal surface pulsed to ultra-high magnetic field 

(liquid, vapor, plasma, or a mixture of these). There are conflicting 

basic descriptions of if, when, and how plasma should form. A 

common view is that when the metal surface is intensely ohmically 

heated, a resistive metal vapor forms, which expands freely through 

the magnetic field. The vapor carries little current, remains cool, and 

therefore forms no plasma. In contrast, other scientists argue that 

even for sub-megagauss magnetic fields, high conductivity plasma 

will form and then be ohmically heated to very high temperature. 

Whether or not plasma should form from a conductor pulsed with 

intense current is vital to a wide variety of applications. Therefore, 

developing a predictive capability is a fundamental challenge for 

plasma physics. 

Awe and collaborators examined the interaction of intensely 

ohmically heated metal and pulsed, ultra-high magnetic field by 

driving intense current on the surface of thick conducting rods. The 

current is generated by the Zebra z-pinch at the Nevada Terawatt 

Facility, which delivers 1 MA in 100 ns. Initial rod diameters (D 0 ) 

range from 0.50 to 2.00 mm. These diameters are large enough 

to allow non-uniform current flow, with ohmic heating confined 

to a surface skin layer, yet small enough for peak fields to reach 

several megagauss on the expanding rod surface. The scientists 

learned that for varying magnetic field rise rates, thermal plasma 

would form from a 6061-alloy aluminum surface when the magnetic 

field reaches a threshold level (B threshold ) of 2.2 MG. The research 

produced conclusive evidence of surface plasma formation. Visible 

light radiometry demonstrates that peak brightness temperatures 

(T BB ) exceed 10 electron volts, extreme ultraviolet spectroscopy 



Plasma . . . identifies spectra from multiply ionized Al, and gated 

imaging and laser backlighting indicate that plasma instabilities 

form. In contrast, larger rods (with peak surface fields below the 

2.2 MG threshold) form resistive metal vapor; sub-eV temperatures 

persist, extreme ultraviolet emission is not detected, and no 

plasma instability growth is observed. The experiment offers the 

first detailed study of the threshold for thermal plasma formation 

from a thick Al surface by pulsed multi-megagauss magnetic fields. 

Measurements of phase, temperature, velocity, and ionization 

state as functions of surface magnetic field strength are informing 

radiation magnetohydrodynamic modeling and will facilitate the 

design and engineering of practical high current devices. 

(Top): Brightness temperature, T BB (t) [eV], Al-filtered EUV diode 

signal [V], and change in rod radius ΔR(t) = R(t)-R 0 [mm], for 

D 0 = 1.00 mm rods, and T BB (t) [eV] for D0 = 2.00 mm rods. The 

Zebra current is also plotted. Data are multi-shot averages. (Bottom 

left): Photograph of an “hourglass” load, with D0 = 1.00 mm 

central rod section. The entire assembly (rod, anode, and cathode) 

is machined from a single 3” diameter aluminum cylinder 

to avoid nonthermal plasma production from e.g., arcing electrical 

contacts. (Right): Gated (2 ns shutter) visible light image of 

plasma emission from a D0 = 1.00 mm rod with B surface ~2.4 MG. 

The scientists conducted experiments at the University of Nevada, 

Reno-Nevada Terawatt Facility (UNR-NTF) by a team that included 

Awe and professors B.S. Bauer, S. Fuelling, and R.E. Siemon 

(UNR). Collaborators from the Air Force Research Laboratory, LANL 

[Walt Atchison and Ann Kaul (Materials and Physical Data, X-CP5), 

Rickey Faehl (High Power Electrodynamics, ISR-6), Bob Reinovsky 

(Theoretical Design, XTD-DO), Chris Rousculp (Plasma Theory and 

Applications, XCP-6), and Peter Turchi (Physics, P-DO)], NumerEx, 

and All-Russian Research Institute of Experimental Physics 

(VNIIEF) contributed to this work. The majority of the targets were 

fabricated in Reno, Nevada and the Polymers and Coatings group 

(MST-7) machined some precision loads. The DOE Office of Fusion 

Energy Sciences funded the research. 

Technical contact: Thomas Awe 

Extreme Fluids Team joins 

LANL’s new Center of Mixing 

Under Extreme Conditions 

The Extreme Fluids Team in Neutron Science and Technology 

(P-23), led by Kathy Prestridge, is expanding its efforts to 

understand turbulent mixing. The team applies high-resolution 

diagnostics to study fluid dynamics problems in extreme 

environments, such as shock-driven mixing, variable-density 

decaying turbulence, high-speed microfluidics, and wind energy. 

Now the team has become part of LANL’s new Center of Mixing 

Under Extreme Conditions, directed by Malcolm Andrews, Group 

Leader of Methods and Algorithms Codes (XCP-4). The mission of 

the Center is to: (1) Lead the Laboratory in its diverse activities in 

the areas concerning mix and turbulence under extreme conditions 

as related to stockpile stewardship, weapons, inertial confinement 

fusion, astrophysics, combustion and any other LANL/national 

application in a manner that promotes practical and scientifically 

defensible results; and (2) Lead the Laboratory in the conclusion of 

the appropriate Predictive Capability Framework and National Boost 

Initiative plans through 2020. 

The team’s current work on the horizontal shock tube project 

involves making the highest resolution measurements possible to 

better understand the smallest scales of mixing in turbulent flows. 

The picture in the logo is of vortical structures in simulated 

carbon-carbon burning in supernovae. It will change periodically. 



Extreme . . . Turbulence is as a state of mixing in which there is a 

wide range of length scales containing kinetic energy. The energy 

is transferred from the largest down to the smallest scales of the 

flow. At the smallest scales, molecular mixing occurs. Currently, 

computers cannot simulate such a broad range of scales in shockdriven 

flows. Therefore, scientists are developing models to estimate 

the characteristics of the smallest scales. These models require 

validation against high-resolution experiments. For the first time in 

the world, the Extreme Fluids Team has measured the velocity and 

density fields of a shock driven mixing flow. These results are used to 

understand errors in modeling turbulence. 

(A) 

(B) 

(A) An image of the density field of a heavy gas curtain of sulfur 

hexafluoride (SF6) surrounded by air that is shocked by a Mach 

1.2 shock, then reshocked at 280 microseconds by the reflected 

shock (at image 7). After reshock, the flow becomes turbulent. 

(B) An image of the vorticity field of the shocked curtain, with 

overlaid velocity measurements. The simultaneous measurement 

of the velocity and density fields allows the calculation of densityvelocity 

correlations, which are key parameters for understanding 

turbulence and developing accurate turbulence models. 

The team has begun two new experimental projects: the vertical 

shock tube project, which will study shock-driven mixing of a 

perturbed density interface; and the Variable-density Decaying 

Turbulence project, which will study the turbulent mixing of two fluids 

that decays over time. Both of these new projects will be housed in 

the Turbulence Laboratory, located within the Los Alamos Neutron 

Science Center (LANSCE), TA-53 Staging Area A. NNSA’s Science 

Campaign 4 supports the work. 

The Extreme Fluids team members presented their work at the 

annual American Physical Society Division of Fluids Dynamics 

meeting in Long Beach, Calif. Greg Orlicz, a University of New 

Mexico PhD student, is studying incident Mach number effects on 

turbulent mixing. BJ. Balakumar has made the first measurements 

of Reynolds stress in a turbulent, shock-driven flow. Sridhar 

Balasubramanian presented research on the impact of initial 

conditions on the turbulent mixing transition, part of the LDRD project 

“Turbulence by Design.” Gavin Friedman, a post-baccalaureate 

student, presented his work on the development of a new flow 

system for the initial conditions in the new vertical shock tube facility, 

and Kathy Prestridge chaired the session on Richtmyer-Meshkov 

instabilities. 

The team’s work supports the Lab’s Nuclear Deterrence, Energy 

Security, and Global Security mission areas and the Integrating 

Information, Science, and Technology for Prediction and Materials 

for the Future capabilities. For more information about the Extreme 

Fluids Team, see www.lanl.gov/projects/shocktube. 

Technical contact: Kathy Prestridge 

Growth of defects on inertial 

confinement fusion capsules 

On December 2, Laboratory researchers successfully executed 

experiments to measure the growth of isolated defects driven by the 

ablative Richtmyer-Meshkov instability. Defects (bumps or divots) 

on inertial confinement fusion (ICF) capsules are thought to cause 

jetting of heavy material into the hot spot during an implosion, an 

undesirable consequence of late stage Rayleigh-Taylor growth. 

The Richtmyer-Meshkov instability growth associated with radiation 

ablation sets the initial conditions for subsequent Rayleigh-Taylor 

growth. Therefore, the ablative Richtmyer-Meshkov instability 

must be understood and controlled to optimize late time behavior. 

The ablation process stabilizes the early stage growth and is even 

predicted to decrease the amplitude of the initial perturbation. 

Ignition attempts will utilize tailored driving pulse shapes designed 

to minimize the perturbation amplitude at the onset of Rayleigh- 

Taylor growth. Experiments conducted at the Omega Laser Facility 

(Laboratory for Laser Energetics, University of Rochester, New York) 

are determining the time at which bump amplitudes approach zero. 

Scientists used nine laser beams from Omega to create a moderate 

temperature (60 eV) radiation environment inside a gold hohlraum 

(see figure), ablating and driving the ablative Richtmyer-Meshkov 

instability growth of a two-dimensional array of Gaussian shaped 

bumps. On-axis area backlighting x-ray radiography measured the 

bump areal density at different times following the driving laser pulse 

by recording the transmission of the 2.8 keV Cl He-alpha line (saran) 

through the bumped target with an x-ray framing camera in the H3 

position of the figure. 



Experimental set-up for bump radiography at Omega. X-ray emission 

from a Cl plasma (saran) created by lasers around the H18 

axis was recorded with an x-ray framing camera at 22x magnification. 

Growth . . . Preliminary analysis shows that evolution of 12 micron 

tall and 32 micron wide full width at half maximum (FWHM) bumps 

fit predictions made by radiation hydrodynamic simulations remarkably 

well (see plot). A peak areal density of 30 micron-gm/cc occurs 

at 3 ns. Because the simulations agree to within the error bars of the 

experiments at the times measured, the researchers are confident 

that the simulations are accurate in predicting the inversion time (approximately 

8 ns). Their future experiments will explore this late time 

behavior. 

Experimental and simulated bump evolution for 

Gaussian-shaped bumps. 

The scientists employed standard interferometric techniques (VISAR) 

to examine shock speeds in the plastic targets. The measured 

shock speed of approximately 10 km/s agrees with the predictions. 

The principal investigator for this campaign is Eric Loomis (Plasma 

Physics, P-24). Scott Evans and Tom Sedillo (P-24), Kimberly 

Defriend-Obrey (MST-7), and Steve Batha (Physics Division, P-DO) 

participated. Derek Schmidt, Deanna Capelli, and Jim Williams (MST- 

7) manufactured and metrologized targets, and General Atomics 

fabricated bump and stepped targets. Otto Landen and Dave Braun 

(Lawrence Livermore National Laboratory) were the project leader 

and designer, respectively. NNSA Campaign 10 (Steve Batha, LANL 

Program Manager) funds the work, which supports the Lab’s Nuclear 

Deterrence and Energy Security mission areas. 

Technical contact: Aaron Koskelo 

6 

First Z bosons ever produced 

and reconstructed in heavy 

ion collisions 

The Z boson is an electrically neutral subatomic particle that 

mediates the weak nuclear force. It has a mass 182,000 times that of 

the electron. Unlike the other weak force mediator (the W boson), the 

Z boson does not change particles it interacts with into other types 

of particles. During the lead-lead collisions at the unprecedented 

energy of 2.76 GeV (a factor 14 higher than at the Relativistic Heavy 

Ion Collider) at the Large Hadron Collider at CERN in November, Los 

Alamos researchers participated in data collection at the Compact 

Muon Solenoid (CMS) experiment and began data analysis. Their 

goal is to understand the quark gluon plasma on a quantitative level. 

The first Z boson candidate reconstructed in heavy ion collisions. 

The figure shows the calorimetric and charged particle tracking 

response to a lead-lead collision in the CMS detector plus the two 

muon tracks from the Z0 decay. 

On November 9, the CMS heavy ion dilepton group, convened 

by Subatomic Physics (P-25) postdoctoral researcher Catherine 

Silvestre, found the first Z boson ever produced and reconstructed 

in heavy ion collisions. The Los Alamos team was responsible for 

including the Z0 measurements in the CMS heavy ion technical 

design report enabled by LDRD funding that began in 2006. 

Preparation for the current dilepton analysis was made possible by a 

second LDRD begun in 2009. Part of the funding supports theoretical 

predictions of Z0 and hadronic jet productions. A CERN seminar 

on the first results from heavy ion collisions was held on December 

2. The CMS talk featured a preliminary dimuon mass spectrum 

with 27 identified Z bosons. The manuscript in preparation, “First 

Unambiguous Measurement of Jet Fragmentation and Energy Loss 

in the Quark Gluon Plasma,” includes principal investigator Gerd 

Kunde, Melynda Brooks, Pat McGaughey and Catherine Silvestre 

(Subatomic Physics, P-25); Andreas Klein (P-23); Ivan Vitev and 

Bryon Neufeld (Nuclear and Particle Physics, Astrophysics and 

Cosmology, T-2). 

Physics Flash—Newsletter of the Physics Division

First neutron image 

collected at the 

National Ignition Facility 

On February 17, the LANL and Livermore National Laboratory 

neutron imaging team obtained its first neutron pinhole image at NIF. 

The target was a deuterium/tritium-filled directly-driven glass microballoon 

with a measured yield of 2 x 10 14 neutrons. In a “direct-drive” 

experiment, all the laser beams impinge on the target. The pinhole 

assembly was aligned with remarkable precision, pointing within 40 

micrometers of the target location and parallel to the line of site within 

200 microradians. The measurement completed the operational 

qualification of this diagnostic. 

The NIF neutron imaging system is designed to produce images 

from implosions of deuterium- and tritium-filled capsules. The 

Inertial Confinement Fusion project’s ultimate goal is ignition of 

thermonuclear fuel in a laboratory setting. The neutron imaging 

system will play an essential role in understanding the performance 

of these implosions by providing key diagnostic information on the 

shape and compression of the implosion. The imaging system will 

take two pictures using two separate camera systems, one of direct 

neutrons from fusion reactions and one of scattered neutrons from 

the material surrounding the burning nuclear fuel. 

The neutron imaging system forms magnified “pinhole” images of the 

neutrons generated in capsule implosions. Because neutrons are 

only generated in the regions of the fuel with sufficient temperature 

and pressure for fusion, these images provide a measure of the 

size and shape of the burning deuterium-tritium fuel. Some fusion 

neutrons are scattered within the material surrounding the burning 

core, losing energy in the scattering process. Due to the long flight 

path between the target and the neutron imaging detector, 

the primary 14-MeV fusion neutrons arrive at the detector 

approximately 50 ns before the down-scattered 10-12 MeV neutrons. 

Two fast-gated camera systems measure the distribution of the 

primary and the down-scattered neutron images. The data from the 

down-scattered neutrons provide a measure of the distribution of the 

“cold” fuel surrounding the burning core. 

The principles behind this imaging technique are similar to the 

principles for the standard pinhole cameras that are common in 

photography. The major difference lies in the penetrating ability of 

10-14 MeV neutrons. The “pinholes” used to form neutron images are 

small tapered apertures machined in approximately 20 cm of gold or 

tungsten. The thick gold or tungsten is required to remove neutrons, 

and the tapered aperture is designed to provide a “sharp” edge for 

the neutron aperture. The triangular pinholes were machined in the 

surfaces of the gold layers. For a magnification factor of 85, the 

pinhole is located close to the source, within the NIF target chamber 

at 32.5 cm from the source, and the image was collected in the 

neutron imaging annex, which is 28 meters from the center of the 

target chamber. 

Neutron image collection system as installed in the neutron imaging 

annex at NIF. The neutrons interact with the scintillating fiber 

array, generating light that is directed towards to image collection 

systems. Light exiting the front of the scintillator is collected with 

an optical lens and transported to a micro-channel plate, for fast 

gating, and on to a CCD (charge-coupled device) camera. The 

light exiting the back of the scintillating fiber array is collected with 

a fiber taper and transported to a micro-channel plate for fast gating 

and through a fiber bundle to a second CCD camera. 

The figure shows the first image data of a directly driven glass 

micro-balloon. Each pinhole in the array points at a slightly different 

location at the target chamber center. Scientists used the neutron 

intensity through each pinhole to estimate the pointing of the pinhole 

array. Preliminary analysis revealed that the pinhole within the black 

box was pointed closest to the source, and the center of the black 

box was centered on the pinhole field of view. Researchers extracted 

this region of the image for further analysis to reconstruct the source 

distribution. 

(Left): first neutron image from the micro-balloon target. (Right): 

microscope view of the pinhole array. The triangular “pinholes” 

form the pinhole images, while the penumbral apertures also provide 

information on the source distribution. 



Neutron . . .The results of this reconstruction show an oblate 

source, as expected in polar driven capsules. Because NIF is 

configured for hohlraum driven (indirect drive) implosions, the 

lasers are directed along the polar axes of the target. In this drive 

configuration the compressed core is expected to be prolate, 

because of the increased drive at the poles of the capsule. This 

result agrees with expectations of the capsule implosion and with 

the x-ray images of the same experiment. The x-ray images show 

different source distribution than the neutron images because the 

physics processes generating the x-rays differ from the processes 

generating the neutrons. 

Physics, Materials Science and Technology, and Weapons Systems 

Engineering divisions performed the work in collaboration with a 

team from Lawrence Livermore National Laboratory. The LANL 

work was funded by the NNSA Inertial Confinement Fusion program 

(Steve Batha, program manager for Campaign 10) for the National 

Ignition Campaign. The research supports the Laboratory’s Nuclear 

Deterrence and Energy Security mission areas and the Science of 

Signatures capability. 

Technical contact: Frank Merrill 

Celebrating service 

Congratulations to the following Physics Division 

employee celebrating a service anniversaries this month: 

Nicholas King, P-23 40 years 

is published by the Experimental Physical Sciences Directorate. 

To submit news items or for more information contact Karen Kippen, 

EPS Communications Team, 606-1822, or kkippen@lanl.gov. 

LALP-11-014 

Los Alamos National Laboratory, an affirmative 

action/equal opportunity employer, is operated 

by Los Alamos National Security, LLC, 

for the National Nuclear Security Administration 

of the U.S. Department of Energy under contract 

DE-AC52-06NA25396. 

A U.S. Department of Energy Laboratory. 

HeadsUP! 

Your chance to slip safely! 

The Voluntary Protection Program (VPP) Office has researched the 

use of a slip simulator used by United Parcel Service (UPS) and 

designed by Virginia Tech that has significantly reduced slip injuries 

at UPS. As a result the Lab has purchased three simulators and is 

taking a similar approach to address slip injuries. 

The objective of a slip simulator is to provide a kinetic learning 

module (“learn by doing”) that has participants experience a slippery 

surface without the risk of falling due to a built-in fall arrest system. 

According to VPP Project Leader Bethany Rich, “This experience 

raises awareness of the importance of walking speed, selection of 

shoe soles, and placement of your center of gravity.” 

Joint efforts behind unique 

safety initiative 

A LANL slip simulator 

reproduces conditions 

that lead to slip and 

fall accidents, in this 

case carrying a box 

across a slick surface. 

Trainees on the system 

are also tasked 

with walking—and not 

slipping—while texting 

on a Blackberry. A 

combination of modified 

footwear, a safety 

harness, and a highly 

polished floor surface 

create the perfectly 

controlled accident 

waiting to happen. 

“While many improvements have been made by Worker Safety and 

Security Teams (WSSTs) and managers to improve our facilities 

and walking surfaces across the Lab, we will never have a perfect 

environment,” said Rich, “and as Human Performance Improvement 

(HPI) reminds us, being humans, we will always make mistakes. 

This [initiative] offers workers one more tool to help take better care 

of ourselves and each other.” 

“We’re pleased that the number of slips, trips and falls is starting 

to decline, but we would like to see the number of injuries 

reduced even further,” said Chris Cantwell, associate director for 

Environment, Safety, Health and Quality. “The combination of VPP 

efforts, WSST participation, HPI initiatives, and Behavior Based 

Safety activities have resulted in this unique and forward-thinking 

safety initiative that I believe will take us to a new level of safety 

performance.” 

When the slip simulators are ready for general use, the VPP Office 

will notify workers how to sign up for free workshops.

LANL: Physics Flash April 2011 - Los Alamos National Laboratory

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