Neutron Sciences Directorate

The Oak Ridge National Laboratory is building VENUS, a world‐class neutron imaging instrument that will uniquely utilize the Spallation Neutron Source (SNS) to measure and characterize large‐scale and complex systems for U.S. research programs including Basic Energy Sciences, Biological and Environmental Research, Energy Efficiency and Renewable Energy, and the National Institutes of Health. VENUS will provide academia, industry and government laboratories with the opportunity to advance research in energy materials and processes, materials science, additive manufacturing, mechanical and physical behavior, geosciences and petroleum applications, transportation research, building technologies, plant physiology, biology, archeology, and a range of other areas.

Description

As its name indicates, VENUS is designed to be as versatile as possible to encompass the largest range of applications, while being fully optimized to benefit from the unique capabilities of SNS.

The range of cold to epithermal neutrons at SNS will give users of VENUS access to novel imaging methods, as well as to significantly improved existing methods. The epithermal flux available at SNS will provide additional possibilities for contrast extension and/or enhancement.

The time-of-flight (TOF) neutrons provided at SNS will offer easy and cost-efficient access to energy-selective imaging, hence making use of neutron scattering Bragg features for improved contrast and identification of phases in an absorption image.

The high peak flux of SNS is useful for stroboscopic imaging of repetitive or cyclic motions and is synchronized to a selected neutron energy range for enhanced image contrast. VENUS will also provide simultaneous x-ray imaging capabilities, as a complementary imaging modality.

The energy, E, or wavelength, λ, of the neutrons can be determined by TOF:
Where t is the time of detection, t_e is the time of emission, and L is the distance between the source and the detector, where the image is formed.

The energy dependence is important because many samples have crystalline components where Bragg scattering can give significant energy-dependent, material-specific variations in attenuation. Microstructures, crystal planes and textures (i.e. grain orientation) can be energy-dependent mapped, along with residual stress (by detection of Bragg shifts). At SNS, all energies are collected at once, reducing acquisition time from several days to a few hours, with the luxury of acquiring neutron data at high TOF resolution. This provides the freedom to later combine, divide, and post-process the data two, three, and four (x, y, z, λ)dimensions.

Supported by SNAP

While VENUS is being constructed, scientists and engineers are using the SNAP diffractometer, SNS BL-3, as a testbed to develop and commission many of the optical devices and instrumentation that will be installed at the new imaging beamline. See the related articles listed below for more information.  

• Neutrons help GE observe real-time stress reduction in 3-D printed parts

• Real-Time Evaluation of Residual Strain Improves 3-D Printed Metal Parts

• Neutron Imaging Enables Optimized Annealing for Inconel Components Made by Additive Manufacturing