Manticoran News Bureau: Fat Man and Little Boy

The crew of HMS Avalon poses in front of one of the most secure facilities in the United States.

Fat Man and Little Boy

by Lieutenant Commander William Knight, HMS Avalon

2015.04.22 CE / 346.12.15 AL (MNB) – On 11 April 2015 at 07:30, Pinnace Two departed from the HMS Avalon to begin picking up officers, crew and civilian guests for a five hour tour of the Los Alamos Neutron Science Center. The away team, consisting of Commander Dan Brandow, Lieutenant Commander William Knight, Ensign Michael Roybal, CPO Jacob Sandoval, SP3/C Amrit Khalsa, and SP3/C Rob Clevenger of the HMS Avalon, as well as civilian guests Joseph Bradley, Shawn Crowder, Marion Dubois, Josiah Mulligan, and Emily Peak met at a breakfast café local to Los Alamos, New Mexico, and once assembled departed for the Los Alamos Accelerator, arriving at 09:00.

Upon arrival Commander Brandow transferred command of the landing party to his Executive Officer, Lieutenant Commander Knight, who works at the facility as an environmental Health Physicist and arranged the tour. The team was then taken through security onto the facility property, and issued visitors badges. Once on site, LANSCE facility scientist Matthew Murray gave an overview of the LANSCE facility, which included a safety overview as well as photos and brief movies of some of the past and current projects being performed by the facility.

(L-R) Commander Brandow, Ensign Roybal, and Lt. Commander Knight pose next to replicas of the original contact nuclear devices – code named “Fat Man” and “Little Boy.

The team then took a tour of some of the highlights of LANSCE including the injector building where the protons are generated and the drift tube and coupled-cavity linear accelerators which accelerate the protons to eighty percent of the speed of light.These near light speed protons, being charged particles, are then delivered to various parts of the facility using high current electromagnets magnets to bend the beam and deliver it to various experimental areas such as the Lujan Neutron Scattering Center, the Isotope Production Facility, the Proton Radiography Facility, and the Ultra Cold Neutron Facility.

The core LANSCE facility is one of the nation's most powerful proton linear accelerators or LINAC. The 800-mega-electron-volt (800 MeV) LINAC provides beam current, simultaneously, to experimental facilities with unique capabilities. The LINAC provides the beam current required by all the experimental areas that support NNSA-DP and other DOE missions. The first stage of the accelerator contains injector systems for each kind of particle (H + and H-). Each injector system has a 750-keV Cockroft-Walton generator and an ion source. The two ion sources produce H + and H- particles inside high-voltage domes. After they leave the injector, the two ion beams are merged, bunched and matched into a 201.25-MHz drift-tube linear accelerator (linac) for further acceleration to 100 MeV. The third and longest stage of the accelerator (800m) is the side-coupled-cavity linac, where particles are accelerated to their final energy of 800 MeV. The particle beams from the linac are separated and directed down three main beam lines leading to several experimental areas including pRad, UCN, and the Lujan Center and WNR operations area. Operators can control the H + and H- beams separately, allowing most experiments to run simultaneously.

The 201.25-MHz drift-tube linear accelerator; the coolest-sounding device ever built.

They also visited the Lujan Neutral Scattering Center, which has instruments that operate in time of flight mode receiving neutrons from a tungsten spallation target. Four moderators provide epi-thermal, thermal and cold neutrons to specialized beamlines, operating for a total of 3,000 hours per year. At the core of the Lujan Center is a 20Hz spallation neutron target and the LANSCE proton accelerator, which operates at an energy of 800 MeV with typical beam currents of 100 – 125 µA. The Lujan Center's highly optimized tungsten spallation target provides a high peak flux with a broad wavelength bandwidth per frame. Two liquid hydrogen moderators provide high intensity cold neutron beams ideally suited for reflectometry, inelastic scattering and small angle scattering. In addition to the highly versatile and modern suite of beamlines, the Lujan Center offers access to a large variety of specialized sample environments, including low temperatures down to 40mK, magnetic fields up to 11T, high temperature furnaces up to 2400C and uniaxial stress (F_max=250kN) and fluid as well as anvil cell pressure capabilities (30GPa-2000K).

Then they moved on to the Isotope Production Facility. Los Alamos has produced radioactive isotopes for medicine and research since the mid-1970s, but it wasn’t until the early 90’s that they upgraded and improved the irradiation capabilities of the radioisotope program, resulting in the separate facility. The IPF facility utilizes a 100 MeV proton beam extracted from the main LANSCE accelerator and directed to a modern target irradiation facility. They also have a Proton Radiography Facility; a field of science actually invented at Los Alamos National Laboratory. It provides a unique understanding of the fundamental behavior of materials. The proton radiography project has used 800 MeV protons, provided by the LANSCE accelerator facility at LANL, to diagnose more than 300 dynamic experiments in support of national and international weapons science and stockpile stewardship programs. Through this effort significant experience has been gained in using charged particles as direct radiographic probes to diagnose transient systems.

This set of radiographs taken after various metals were shocked from below reveals radically different behavior;

for example, the aluminum sample splits into layers while the tin sample melts.

The last facility they saw was the LANSCE Ultracold Neutron (UCN) source. It’s a unique facility that produces high energy spallation neutrons and uses solid deuterium to cool the neutrons by one million billion-fold. The resulting UCNs have some unique properties that allow them to be studied precisely: they move at speeds of only a few meters per second, and are completely confined by magnetic fields and material bottles for many hundreds of seconds at a time. These properties lead to very precise low energy particle physics experiments that search for small differences between measurement and prediction, and these precision measurements are a powerful tool for investigating new physical processes which can complement and rival experiments at high energy colliders such as CERN. There are several new and on-going experiments at the UCN source that measure decay correlations and other properties of the neutron. This program of measurements probes the particle physics underlying neutron decay, and has important implications for high energy physics and cosmology.

The Accelerator portion of the tour concluded at approximately 14:00, and Lieutenant Commander Knight requested and was granted relief of command by Commander Brandow. The landing party then returned to Los Alamos and had lunch, followed by a visit to the Bradbury Science Museum, which is operated by the Los Alamos National Laboratory and displays approximately 40 interactive exhibits which trace the history of the WWII Manhattan Project, highlight the Laboratory's current and historic research projects related to defense and technology, and focus on Laboratory research related to national and international economic, environmental, political, and social concerns. The tour concluded at approximately 15:30. Civilian personnel returned to their daily activities and ship personnel departed for their assigned duty locations. Everyone left the facility wowed by the immensity of scientific research.

What this place looks like from the sky.

Article Copyright © 2015, Bureau of Communications, The Royal Manticoran Navy: The Official Honor Harrington Fan Association, Inc.
CAPT (JG) Marcus Johnston, Director of Publications, BuComm. All text and pictures have been used with permission of LANL and are approved for unrestricted release.

(That’s so cool! How often do I get to say that?!)