Sandia LabNews

Sandia researchers win three R&D 100 Awards

Three Sandia research teams — one from New Mexico and two from California — have won R&D 100 Awards in the annual competition for innovative technology sponsored by R&D Magazine, a trade magazine based in the Chicago area.

Teams of technical experts chosen by the magazine select 100 winners of the annual contest. The winners must not only be original but also show promise of real-world application.

Prizes in the form of plaques will be presented at a banquet hosted in October by the magazine at Chicago’s Museum of Science and Industry.

The Sandia winners invented an Ion Electron Emission Microscope, polymer hydrogen getters, and a new process for growing compound semiconductors of cadmium-zinc-telluride for room temperature radiation detection.

"Sandia’s R&D 100 winners this year represent those fundamental advances in technology that are so essential for making progress in other fields," says Labs President and Director C. Paul Robinson of the awards. "All three awards represent new inventions, and all three make significant strides in extending the state of the art, but at the same time each is extremely cost-effective over past methods.

"Developing such ‘systems solutions’ is what we have been emphasizing as Sandia’s reason for being, and it is very rewarding to see the R&D 100 Awards honor the work. I am also pleased that two of the three awards included team members from industry and universities. Technology partnerships are also a major thrust, and these awards indicate just what is possible through such teaming efforts."

Summaries of the winning technologies follow:

Ion Electron Emission Microscope

The Ion Electron Emission Microscope (IEEM), invented by New Mexico-based researchers Barney Doyle and George Vizkelethy (both 1111), Robert Weller of Vanderbilt University, and Berthold Senftinger of Staib Instruments Inc. in Germany, is the first device that allows scientists and engineers to microscopically study the effects of single ions on semiconductors, integrated circuits, and biological specimens without having to focus the MeV ion beam. The IEEM nomination was submitted jointly by Sandia and Staib, the company currently manufacturing the microscope.

Barney says that unlike earlier microscopy systems, one version of the IEEM — the alpha-source IEEM — doesn’t even use an accelerator.

"It replaces a building full of expensive accelerator and nuclear microfocusing equipment with a device the size of a scanning electron microscope," Barney says. "It will also be a fraction of the cost of a conventional nuclear microprobe."

The low cost and size comes at no reduction in capability and even enables for the first time some experiments using accelerators, which were previously considered unsuitable for nuclear microscopy.

Barney speculates that this development "could well lead to a renaissance in nuclear microscopy, particularly for studying electron transport in semiconductors and microelectronics and for radiobiology research."

Instead of focusing high-energy ions like the Hybrid Nuclear Microscopy System (Lab News, Sept. 22, 2000), which has been the standard form of locating problem areas in radiation-hardened integrated circuits for the past decade, the IEEM technique determines the position where an individual ion enters the surface of the sample by projection secondary electron emission. These position signals are then correlated with the ion-induced signal generated in the sample or device under test.

The IEEM comes in two forms, one using a particle accelerator, and one using a radioactive alpha particle source.

"The main advantage of the accelerator-IEEM over commercial focused beam nuclear microprobes is the low-cost and small size, even after it is integrated into a beam," he says. "The IEEM system will also allow us to perform Radiation Effects Microscopy using the highly ionizing beams from the Radio Frequency Quadrupole linac booster recently added to the tandem accelerator in the Ion Beam Materials Research Lab in Bldg. 884.

"For the alpha-IEEM, future prospects are equally exciting because no accelerator is required — just an alpha-particle source deposited on the objective aperture. The cost for the complete system is $100,000, compared to the multimillion dollar system for focused microbeams, which require accelerators," Barney says.

Polymer Hydrogen Getters

Tim Shepodd (8722), co-inventor of the polymer hydrogen getters (Lab News, May 5, 2000), calls the product the "greatest advance in getters in 50 years."

The getters permanently and irreversibly remove unwanted hydrogen and, as a result, can prevent explosions caused by hydrogen mixing with the atmosphere in sealed consumer products and avert hydrogen buildup that can result in a decrease of insulation properties or loss of efficiency in evacuated heat exchangers.

Tim and LeRoy Whinnery (8722) of Sandia/California are receiving the R&D 100 award for inventing the polymer hydrogen getters.

"Our getters allow the safe use of sealed, battery-operated devices such as flashlights, dive-lights, toys, and cameras without the risk of inadvertent detonation," Tim says.

It is long known that alkali and carbon/zinc batteries give off hydrogen. In unsealed devices, the hydrogen poses little danger because it is rapidly diffused. Batteries in sealed devices, however, easily yield sufficient hydrogen to create an atmosphere if over-drained, charged, or inverted.

The polymer hydrogen getters function in two ways. They either scavenge hydrogen with carbon-carbon multiple bonds, or, when oxygen is present, safely make water through recombination. The Sandia getters are customized for each customer, made from readily available ingredients, nonhazardous, and designed to remove hydrogen in a variety of atmospheres, including vacuum, inert, air, or steam.

"Polymer hydrogen getters are a spectacular example of an enabling technology," Tim says. "They are deployed as a small, passive part of numerous technologies and are usually less than one percent of the mass and cost. Yet without getters, the entire technology may not be able to be safely or economically deployed. A flashlight that explodes, a camera that could malfunction or explode — these consumer products are made safe by our technology."

Sandia’s polymer hydrogen getters are currently marketed under a licensing agreement with Vacuum Energy Inc. of Cleveland, Ohio.

Solid-State Radiation Detectors

Detection and imaging of nuclear materials, such as radiotracers in nuclear medicine, just got easier. The reason is a new technique of growing large single crystals of cadmium zinc telluride (CZT) suitable for producing radiation detectors. The technique was developed by a team of researchers from Sandia/California; Yinnel-Tech Inc. in South Bend, Ind.; Techion — Israel Institute of Technology; and Fisk University.

"Progress in the area of solid-state X-ray and gamma-ray detectors has been linked to producing better crystals. Our discovery of a technique to grow large single crystals of CZT with the desired electrical properties has begun to transform the technology area, creating new thrusts and directions for solid-state radiation sensors and imaging arrays," says Ralph James, who served as the Sandia principal investigator for the project. He left the Labs this spring to join Brookhaven National Laboratory as Associate Laboratory Director.

The solid-state radiation detectors based on semiconductor materials made from cadmium zinc telluride are unique because they can operate at room temperature, detect X- and gamma-ray radiation with high efficiency, and uniquely identify the isotopes responsible for the emitted radiation.

The team’s development of an improved technique to grow detector-grade CZT crystals and a new method to reduce the dark current flowing along the crystal surfaces have allowed for major improvements in the signal-to-noise ratio, long-term stability, and yield of single-crystal material.

Ralph says the detectors have diverse applications, ranging from environmental cleanup, imaging of gamma-ray bursts, radiography, and safeguarding the world’s inventory of nuclear materials to improved detection of tumors and heart disease.

Before the team developed the new technique, a detector capable of distinguishing natural background emanating from common building materials and the radiation characteristics of many isotopes relied on bulky equipment that had to be cooled to super-low temperatures and attended frequently by a technician. Preparing the equipment for use required precooling for a few hours.

Radiation detectors produced from these new materials need no cooling, are easy to use, require little or no maintenance, and provide the capability to identify radioactive sources in the field, Ralph says.

CZT detectors had been produced using other growth techniques, but the low yield of large-volume single crystals limited the detectors’ efficiency and availability and led to costs that were prohibitively high for several applications. The cost reduction for large, single crystals of CZT has enabled a more widespread use, particularly for imaging applications.

Team members from Sandia included Eilene Cross (8517), Jay Erickson (former student intern), Richard Olsen (8724), Gomez Wright (former student intern), and Walter Yao (now at Advanced Micro Devices, Inc.).