Develops high-performance optical sensors for various applications, including radiation dosimetry, optical and nuclear imaging, and scientific research.

Research Areas:
	Solid-state Photomultipliers (SSPMs)
	Radiation Dosimeters and Spectrometers
	Vertex Detectors for High-energy Physics
	High-performance CMOS-based Geiger Photodiodes (GPDs)
	Nuclear Imaging

     These high-density arrays of CMOS Geiger-mode, silicon avalanche photodiodes are made with inexpensive CMOS technology. They can provide very high gain, for high sensitivity measurements, with a very fast response time needed for a variety of optical and nuclear detector applications.

Direct Photon-counting Scintillation Detector Readout using an SSPM

CMOS Solid-State Photomultiplier for Detecting Scintillation Light in Harsh Environments

Solid-State Photomultiplier in CMOS Technology for Gamma-Ray Detection and Imaging Applications

     The dosimeter-on-a-chip couples an SSPM to a scintillation crystal to provide the energy spectrum for dosimetry and gamma ray spectroscopy applications. The scintillation-based dosimeter provides excellent sensitivity to gamma rays and neutrons, and the gamma ray spectral information improves the assessment of dose by the dosimeter chip.

Characterization of CMOS Solid-state Photomultiplier for a Digital Radiation Rate Meter

     Vertex tracking has become indispensable for particle characterization in modern high-energy physics experiments. Stacked arrays of sensor elements track multiple particles created in a single event, and tracing these particles back to the intersection, or vertex, can help identify the nature of the particle. We are developing an array of avalanche photodiodes with internal gain to drive rapid event driven readout: the CMOS avalanche photodiode Active Pixel Sensor (APS) array for tracking particles in the next generation of colliders.

CMOS-based avalanche photodiodes for direct particle detection

Next Generation Active Pixel Sensor Device with CMOS Avalanche Photodiodes

     Actively quenched GPD arrays provide the speed and sensitivity needed to prove the flow of blood in underlying tissues using the time-dependence of the photon scattering. The GPD pixel elements detectors tranduce the incident photon flux into a digital count rate, which eliminates the readout noise associated with traditional analog pixel elements.

Characterization of a CMOS Geiger Photodiode Pixel

CMOS Geiger Photodiode GPD Arrays & SSPMs for Room Temperature Operation

     The IRD Group investigates technologies to improve the performance and lower the cost of gamma cameras for both standoff radiation imaging and medical imaging applications, such as PET and SPECT.

Standoff Radiation Imager for Homeland Security
     This nuclear camera combines a large area sensor with coded-aperture technology to produce images and spectral information to identify and locate sources at substantial distances. (More information on the RadCam™ Coded Aperture Gamma Camera).

Coded Aperture Imaging [3,999 KB]

Advanced multi-dimensional imaging of gamma-ray radiation

Portable Video/Gamma Camera for Surveillance, Safeguards, Treaty Verification and Area Monitoring [357 KB]

IG CMOS APD Camera for SPECT
     This work investigates the construction of a high spatial-resolution SPECT detector composed of a CsI (Tl-doped) scintillation array and an aligned, pitch-matched CMOS camera chip. The CMOS-camera chip integrates the pixel-level readout components with the internal-gain CMOS-APD pixels in a monolithic device for small-animal SPECT imaging.

Internal-gain CMOS APD Pixels for SPECT Imaging of Small Animals [15 pp; 17,836 KB]

PET & SPECT Imaging using SSPMs
     We are developing SSPMs, and position-sensitive SSPMs, for PET and SPECT applications. These detectors provide excellent sensitivity and timing performance for these demanding imaging applications.

CMOS ASIC Development
     High-resolution PET imaging requires many detectors and signal processing electronics with properties including high sensitivity for small signals and high speeds for coincident detection. We condense these complex readout electronics onto an ASIC chip.

An Application-Specific Integrated Circuit for Positron Emission Tomography [384 KB]

ASIC Readout Unit - Preliminary Product Description [21pp; 1,782 KB]