LLNL researchers have developed a TDLAS-based, standalone, real-time gas analyzer in a small form-factor for continuous or single-point monitoring.  The system can analyze multiple gases with ultra-high sensitivity (ppm detection levels) in harsh conditions when utilizing wavelength-modulation spectroscopy (WMS). 

A thyristor will stay conducting until the current through the device is zero (“current zero”) or perhaps slightly negative.  LLNL’s approach is to use the opticondistor (“OTV”) to force this current zero in order to force the device into an “off” state.  By combining a light-activated thyristor with an OTV, a noise-immune, high efficiency, high-power switching device can be constructed. The…

The researchers’ approach leverages the concept that dopants have high diffusivities in Ga2O3; the key lies in the selection of the appropriate dopant.  This LLNL invention describes two device types that employ this design:

Design and construction of a photoconductive switch requires a diamond photoconductor illuminated by light of a certain excitation wavelength. 

Characteristics of the LLNL-developed switch are as follows:

LLNL researchers have invented an ultrafast PCSS to drive a high-power laser diode with arbitrary pulse widths.  These devices operate by supplying a high voltage (>10 kV) to one side of the switch.  A short pulse of light illuminates the semiconductor, instantly turning it from highly resistive to highly conductive.

This novel detector for characterizing IFE implosions is an alternative to the current RTNADs to measure neutron fluxes > 3x10¹¹ neutrons/cm² at high shot rates. The detector consists of a stack of small square metal wafers separated by thin insulating spacers. Every other wafer is held at high voltage while the remaining wafers are grounded. The stack acts as an…

U.S. Patent No. 11,555,965 describes LLNL’s invention of “Illumination Frustums” for photoconductive switches to capture and “frustrate” the light from leaving the frustum.  LLNL researcher’s latest novel invention, “Twister Oven”, achieves this by encouraging laser light absorption in a photo conductor material.  Light enters the oven twisting and reflecting, making near normal incident multi…

Design and construction of a photoconductive switch requires a diamond photoconductor illuminated by light of a certain excitation wavelength.  The diamond material is chosen to be doped with substitutional nitrogen to act as a source of electrons.  The device architecture allows maximum light entering the aperture.  The top and bottom electrodes are made of ultra-wide bandgap (UWBG)…

LLNL researchers faced this challenge by bridging the gap between VEDs and solid-state electronics (SSE).  Their approach was to create a hybrid vacuum microelectronic device (VMD) architecture that combines the properties of vacuum as the electronic medium and the compact form factor and manufacturing scalability of semiconductor microelectronic chips.

Design and construction of a photoconductive switch requires a diamond photoconductor illuminated by light of a certain excitation wavelength.  The diamond material is specifically doped with substitutional nitrogen, which act as a source of electrons.  The device architecture allows maximum light entering the aperture.  The top and bottom electrodes are made of ultra wide band gap (UWBG)…

The approach is to use a custom-designed frustrum and attach it to the optical fiber that connects to the PCSS.  Light from the fiber enters the frustrum, spreads out, and enters the PCSS.  Any unabsorbed light re-enters the frustrum and, because of its geometry, reflects back into the PCSS itself with only a negligible fraction escaping from the fiber.  The shape of the novel frustrum is…

LLNL’s SAS technology embedded within a facility is developed to sense, detect, localize, alert, and communicate an active shooter(s) to first responders.  It relies on three integrated compact sensors that detect sound, infrared light (from the muzzle blast) and vibrations emanating from a gunshot.  Fusing the data from these detectors minimizes false alarms.

The key to time-reversal for an active shooter detection/tracking application is being able to estimate the space-time transfer function (Green’s function) between source-enclosure-receiver.  This approach begins with the acoustic mapping of an indoor muzzle blast. 

LLNL researchers have designed and tested performance characteristics for a multichannel pyrometer that works in the NIR from 1200 to 2000 nm. A single datapoint without averaging can be acquired in 14 microseconds (sampling rate of 70,000/s). In conjunction with a diamond anvil cell, the system still works down to about 830K.

The invention utilizes the statistical nature of radiation transport as well as modern processing techniques to implement a physics-based, sequential statistical processor. By this we mean that instead of accumulating a pulse-height spectrum as is done in many other systems, each photon is processed individually upon arrival and then discarded. As each photon arrives, a decision is…

LLNL's neutron "Pillar Detector" fabrication technology uses semiconductor-based micro-structured elements as an electrical signal generation medium for the detection of neutrons. These materials in the form of semiconductor "pillars" embedded in matrix of high cross-section neutron converter materials (such as Boron) that emit charged particles upon interaction with neutrons. These charged…

Transparent ceramic fabrication allows the production of gadolinium- , lutetium-, and terbium-based garnets which are difficult to grow by melt techniques due to phase instabilities. Phase stabilization of the garnets is accomplished by the addition of the intersubstitutional ions, Gallium and/or Scandium.

Scientists have developed many versatile and scaleable fabrication methods.…

LLNL's high fidelity hydrocode is capable of predicting blast loads and directly coupling those loads to structures to predict a mechanical response. By combining this code and our expertise in modeling blast-structure interaction and damage, along with our access to experimental data and testing facilities, we can contribute to the design of protective equipment that can better mitigate the…

LLNL researchers have grown and characterized scintillator crystals of Strontium Iodide (SrI2). Scintillator energy resolution and light yield proportionality surpass NaI and are similar to LaBr3. The SrI2 scintillators doped with europium (Eu) exhibit very high light yields (> 100,000 photons/MeV), extremely good energy resolution (<3% at 662 keV) and excellent light yield…

The LLNL detector measures radiation over a large dynamic range, spanning both high hazardous levels and weak levels, including natural background radiation. In weak radiation fields, the detector also measures gamma-ray spectra. The cost of the detector is significantly less than the total cost of existing separate detectors that could perform the same measurements.

LLNL's X-ray spectrometers based on STJ have been developed for high-resolution soft X-ray spectroscopy. STJ consist of two superconducting thin film electrodes separated by a thin insulating tunnel barrier. They measure X-ray energies from the increase in tunneling current after X-ray absorption in one of the electrodes excites additional charge carriers above the superconducting energy gap.…

LLNL has developed a radiation detector that cools to operating temperatures in 1-2 hours using two separate cooling stages. The first cooling brings the instrument to operating temperature. The embedded second cooling system achieves portable detection that can be sustained for 8-12 hours.

In addition, an integrated, hermetically-sealed package has been developed complete with…

LLNL has identified solution-grown organic crystals having scintillation efficiency not only close to, but even exceeding that of stilbene.. LLNL's invention relates to a new class of neutron detectors based on scintillation response of organic single crystals. More specifically, the use of organic molecules grown from solution and to molecules including the basic benzene or phenyl structure…

LLNL scientists have developed an approach for full spectrum analysis during gamma ray spectrometry using a spectral library signature created from a large amount of spectral data. The signature can be compared to unknown spectral measurements for the identification of previously unknown nuclear material.

Scientists at Lawrence Livermore National Laboratory have developed a plastic that can detect neutrons, something previously thought impossible.

Livermore scientists demonstrated a plastic scintillator that can discriminate between neutrons and gamma rays with a polyvinyltoluene (PVT) polymer matrix loaded with a scintillating dye, 2,5-diphenyloxazole (PPO). They have found that…