Scott J. Morris

Design and implementation of a new autonomous sensor fish to support advanced hydropower development

Acceleration in development of additional conventional hydropower requires tools and methods to perform laboratory and in-field validation of turbine performance and fish passage claims. The new-generation Sensor Fish has been developed with more capabilities to accommodate a wider range of users over a broader range of turbine designs and operating environments. It provides in situ measurements of three-dimensional (3D) linear accelerations, 3D rotational velocities, 3D orientation, pressure, and temperature at a sampling frequency of 2048 Hz. It also has an automatic floatation system and built-in radio-frequency transmitter for recovery. The relative errors of the pressure, acceleration, and rotational velocity were within ±2%, ±5%, and ±5%, respectively. The accuracy of orientation was within ±4° and accuracy of temperature was ±2 °C. The new-generation Sensor Fish is becoming a major technology and being deployed for evaluating the conditions for fish passage of turbines or other hydraulic structures in both the United States and several other countries.

Measurement of Fukushima aerosol debris in Sequim and Richland, WA and Ketchikan, AK

Aerosol collections were initiated at several locations by Pacific Northwest National Laboratory (PNNL) shortly after the Great East Japan earthquake of May 2011. Aerosol samples were transferred to laboratory high-resolution gamma spectrometers for analysis. Similar to treaty monitoring stations operating across the Northern hemisphere, iodine and other isotopes which could be volatilized at high temperature were detected. Though these locations are not far apart, they have significant variations with respect to water, mountain-range placement, and local topography. Variation in computed source terms will be shown to bound the variability of this approach to source estimation.

Electronics system for the GammaTracker handheld CdZnTe detector

We are currently developing a handheld radioisotope identifier containing eighteen position-sensitive CdZnTe crystals. In addition to isotope identification, the device performs basic Compton imaging to determine the location of suspected sources. This paper gives an overview of the electronics system we have designed for this instrument. We use specialized application-specific integrated circuits to preprocess the outputs of each CdZnTe crystal. A low-power microprocessor running Windows CE drives the user interface and implements the isotope identification and directionality computations. Finally, we use a field-programmable gate array to perform the computationally intensive imaging tasks in real time.

Requirements for Xenon International

This document defines the requirements for the new Xenon International radioxenon system. The output of this project will be a Pacific Northwest National Laboratory (PNNL) developed prototype and a manufacturer-developed production prototype. The two prototypes are intended to be as close to matching as possible; this will be facilitated by overlapping development cycles and open communication between PNNL and the manufacturer.

Parallel radioisotope collection and analysis in response to the Fukushima release

Two independent radionuclide aerosol air samplers were operated at Pacific Northwest National Laboratory in close proximity during the Fukushima reactor releases. One system was an automated aerosol collection and analysis unit, whereas the other was a manual sampler of simpler design. The samples collected from each sampler showed correlation in radionuclide activity, although some variations were observed. During this unique event, the small variations observed between the co-located air samplers illustrate the effectiveness of a way to acquire useful parallel samples for scientific purposes. The results in radionuclide activity concentration show that, in some circumstances, use of a manual high volume air sampler in parallel to a complex automated sampler can produce results that are of comparable quality to International Monitoring System samples.

Initial field measurements with the Multisensor Airborne Radiation Survey (MARS) high purity germanium (HPGe) detector array

The Multi-sensor Airborne Radiation Survey (MARS) project has developed a new single cryostat detector array design for high purity germanium (HPGe) gamma ray spectrometers that achieves the high detection efficiency required for stand-off detection and actionable characterization of radiological threats. This approach is necessary since a high efficiency HPGe detector can only be built as an array due to limitations in growing large germanium crystals. The system is ruggedized and shock mounted for use in a variety of field applications. This paper reports on results from initial field measurements conducted in a truck and on two different boats.

Algorithm Implementation for a Prototype Time-Encoded Signature Detector

The authors constructed a prototype Time-Encoded Signature (TES) system, complete with automated detection algorithms that can be used to detect point-like gamma-ray sources in search applications where detectors observe large variability in background count rates beyond statistical (Poisson) noise. The person-carried system consists of two cesium iodide scintillators placed on opposite sides of a lead shield. This geometry mitigates systematic background variation and induces a unique signature upon encountering point-like sources. This manuscript focuses on the development of detection algorithms that identify point-source signatures while remaining computationally simple. The latter constraint derives from the instruments mobile (and thus low power) operation. The authors evaluated algorithms using both simulated and field data. The results of this analysis demonstrate the capability to detect sources at a wide range of source-detector distances using computationally simple algorithms.

DVD based electronic pulser

This paper describes the design, construction, and testing of a digital versatile disc (DVD) based electronic pulser system (DVDEPS). Such a device is used to generate pulse streams for simulation of both gamma and neutron detector systems. The DVDEPS reproduces a random pulse stream of a full high purity germanium (HPGe) spectrum as well as a digital pulse stream representing the output of a neutron multiplicity detector. The exchangeable DVD media contains over an hour of data for both detector systems and can contain an arbitrary gamma spectrum and neutron pulse stream. The data is written to the DVD using a desktop computer program from either actual or simulated spectra. The targeted use of the DVDEPS is authentication or validation of monitoring equipment for nonproliferation purposes, but it is also of general use whenever a complex data stream is required. The DVD based pulser combines the storage capacity and simplicity of DVD technology with commonly available electronic components to build a relatively inexpensive yet highly capable testing instrument.

Unattended sensors for nuclear threat detection

This paper discusses the ongoing development of a compact, unattended low-power radiation detection system designed for autonomous operation in regions with limited or no supporting infrastructure. This application motivates our focus on two of the more challenging system development problems: (1) the development of compact, low-power electronics for gamma-ray spectrometers and neutron detectors, and (2) analysis algorithms capable of distinguishing special nuclear material from benign sources in the opaque signatures of mid-resolution spectrometers. We discuss our development efforts on these fronts and present results based on implementation in a proof-of-principle system composed of two 5-cm × 10-cm × 41-cm NaI(Tl) crystals and eight 40-cm 3He tubes.

Pulse processing system for the RADMAP radiation modulation aperture imager

We are currently developing a portable radiation imager for emergency responders. The instrument contains a position-sensitive photomultiplier tube with a thin CsI(Na) scintillator and a tungsten radiation modulation aperture. As part of this project, we have designed a novel pulse processing system to record the amplitude and position of incident events. This system consists of four charge-to-pulse-width converters that transfer time-modulated digital pulses to a field- programmable gate array. The design can process data at count rates exceeding 40,000 events per second and transmit data over an Ethernet link at 1 Gb/sec.