Research Themes 

• Radiation detection and imaging
• Multi-sensor systems and networks and data fusion
• Utilization of computer vision and data analytics, including machine learning and artificial intelligence

 Applications

• Nuclear security (proliferation detection, safeguards, materials and process monitoring, emergency response and consequence management)
• Radiological safety (monitoring, decontamination and decommissioning, environmental and legacy management)
• Fundamental physics (nuclear structure physics and properties of the neutrino)
• Biomedical imaging (ion cancer therapy verification, targeted alpha therapy verification, multi-tracer imaging)
• Radiological resilience

Outreach (& Training)

• Berkeley Radwatch and DoseNet

Ongoing Research

We are engaged in a broad range of research activities related to radiation, radiation detection and imaging. In addition to developing new concepts and technologies in radiation detection and imaging, we combine them with the enormous advances in multi-sensor data fusion, computer vision, and data analytics. Several of our graduate students work with world-leading scientists at National Laboratories such as Lawrence Berkeley National Laboratory, Lawrence Livermore National Laboratory, or Los Alamos National Laboratory or at the Departments of Radiology and Radiation Oncology at UC San Francisco.

What is particularly exciting in our research is that we can map our technological advances to a wide range of applications in diverse fields such as fundamental physics, nuclear security and radiological safety, or biomedical imaging.

More specifically, our current students are engaging in the following research projects:

Demonstration and enhancement of Scene Data Fusion in complex environments
Scene Data Fusion (SDF) is a new concept that allows us to detect, map, and visualize sources of gamma radiation and neutrons in 3D and in near real-time on almost any platform including unoccupied aerial systems or ground robots. Over the last 10 years, we have deployed SDF in the evacuated areas in Fukushima Prefecture in Japan or on site of the Fukushima Dai-ichi Nuclear Power Station (FDNPS), on site of the Chernobyl Nuclear Power Plant (ChNPP) and in Pripyat in Ukraine, in Germany, and across the U.S. At the core of our compact SDF enabled instruments is the Localization And Mapping Platform LAMP that consists of radiation detectors and imagers as well contextual sensors such as laser-based LiDAR, visual cameras, GPS and IMUs, batteries, and powerful single board computers. The radiation detection systems range from simple CsI(Tl) to new CLLBC scintillator or CdZnTe semiconductor detector arrays that can operate as powerful radiation imaging systems without using passive collimators. One of our students is currently working on the 3D radiation mapping from measurements in and around ChNPP, including the amusement park. The goal is to provide a 3D visualization of the remaining contamination and its quantification in these areas. This work is performed in collaborations with scientists of the Applied Nuclear Physics (ANP) program at LBNL.

Utilize new organic scintillators as structural components
We are exploring the new generation of plastic scintillation detectors that allow the detection of and discrimination between slow and fast neutrons and gamma rays in their use as structural components of small Unoccupied Aerial Systems (sUAS). A range of materials provided by LLNL are studied in optimizing optical and mechanical properties which led to the recent demonstration of a first “scintillation drone”. This project also entails the use these plastic scintillators to complement existing CLLBC-based gamma-ray and neutron detection and imaging systems by providing fast neutron detection and means of active moderation. These tri-modal systems are combined with Berkeley Lab’s LAMP system providing Scene-Data Fusion capabilities for all modes we deploy in hand portable configurations, on drones, or on robots.

Immersive Operation and Visualization of a Semi-Autonomous Aerial Platform for Detecting and Mapping Radiation
A team of undergraduate and graduate students from UC Berkeley’s Electrical Engineering and Computer Science Department is working with us to develop new means to visualize and control our small Unoccupied Aerial Systems. A new immersive Virtual Reality (VR) framework has been developed that allows us to integrate and to visualize and to control SDF enabled sUASs and our scintillation drones. It also allows us to control multiple sUAS with different objectives such as the 3D mapping of environments or the search of radioactive materials.

Advanced data reconstruction concepts in the localization and mapping of radioactive sources
Being able to localize and map radiation sources and extended radiological contaminations with simple radiation detectors remains a challenge in radiological safety and nuclear security. One of our students is developing new concepts in the reconstruction of extended radioactive contamination with simple radiation detectors with the goal to overcome limitations of conventional iterative methodologies such as Maximum-Likelihood Expectation Maximization which bias the reconstructed activities towards the path of the instrument.

Study of advanced concepts in the monitoring of nuclear reprocessing facilities
The goal of IAEA safeguards is to provide timely detection of the diversion of a significant quantity of nuclear material. This is a challenging goal for facilities that handle nuclear materials in bulk forms. The goal here is to develop unique methods to design and operate reprocessing facilities and other nuclear material bulk handling facilities, including molten salt reactors (MSRs), to enable the detection of inadvertent or deliberate hold up of fissionable material with high confidence and low false-positive rates. We are combining advanced concepts in radiation detection and imaging, in modeling and simulations, and in fault detection to achieve these goals.

Development of ultra-fast scintillators
Being able to determine the incident time of radiation such as gamma rays is of great importance in wide range of applications in nuclear and particle physics experiments, proliferation detection and emergency response, and biomedical imaging. Our research covers the study of fast scintillation mechanisms (e.g. as found in BaF2) or Cherenkov radiation and their readouts. We are working with scientists from LANL and LBNL to map our advancements to different applications.

Study of light transport properties in Water-Based Liquid Scintillators
Water-Based Liquid Scintillators (WBLS) promise affordable scaling of radiation detectors to unprecedented volumes (>100,000 metric tons) that could be of relevance for the detection of a range of fundamental particles including (anti) neutrinos, whether for fundamental studies or the detection and monitoring of (anti) neutrino-producing nuclear reactors. Studies to better understand attenuation and scattering properties of light created in these materials are necessary to optimize the design and readouts of such very large detection volumes. We work with scientists at LLNL and perform measurements to characterize fundamental light transport properties in WBLS.

Development and demonstration of a large area and field-of-view cylindrical active mask gamma-ray imaging system – CAMIS
The detection, localization, and tracking of illicit nuclear materials at standoff distances of hundreds of meters remains a challenge. We have developed a large area cylindrical gamma-ray imaging system that consists or 128 (10cm)3 NaI(Tl) detectors which serve as detectors and active coded-mask elements simultaneously. This instrument represents the extension of previous developments of spherical and cubical arrangements of smaller CdZnTe and CLLBC detector elements that are deployed in hand-portable formats or on remotely operating unoccupied vehicles. CAMIS will be mounted on a van and will provide detection, localization, and source tracking capabilities at more than 100-meter distances.

Development of new concepts in the imaging of prompt gamma rays for proton therapy verification
External ion-beam cancer therapy is becoming widely used globally due to its promise in high radiobiological effectiveness due to the delivery of a well localized and high specific energy loss associated with the Bragg peak. One of the outstanding challenges limiting the realization of its full potential is the uncertainty associated with the range of the ions in tissue. We have been developing an advanced gamma-ray imaging system that allows the in-situ estimation of the ion range by using a new two-dimensional knife-edge collimator. Our feasibility studies indicate that we can achieve the necessary high sensitivity and high spatial resolution with the potential to determine the range for each spot of the pencil-beam based raster scan during a treatment.

Development of new concepts in the study of targeted alpha therapy
Recent studies show the enormous potential of using alpha particles emitted from radionuclides that are attached to specific cancer targeting agents to treat even advanced and highly metastasized cancer. Of specific interest is Ac-225 which emits four alpha particles in its decay chain. Although extremely promising, questions remain about the kinetics of the alpha-particle emitting radionuclides. Gamma rays which are also emitted in the decays of Ac-225 could be used to better understand the relevant bio-distribution providing important insights into the effectiveness of specific agents. The challenge in using conventional means of biomedical imaging is the high spatial resolution of ~mm and the very high sensitivity needed in order to perform such studies as the Ac-225 concentration that is being used is much lower than in conventional studies. This challenge is compounded by the different gamma-ray energies which could be used as a fingerprint of the different decay daughters and their energies being higher than the ones typically used in state-of-the art gamma-ray imaging instruments. We are performing feasibility studies with our 3D-position sensitive high-purity Ge detector-based dual-modality coded aperture and Compton imaging instrument what provides high sensitivity and high resolution over the range of gamma-ray energies needed for these studies.