A Sample Activation Program for Neutron-Scattering Experiments

Lu, Wei; Ferguson, P.D.; Gallmeier, Franz X.; Iverson, Erik B.; Popova, Irina; Wang, Y.

doi:10.13182/nt09-a9335

Cited by 2 publications

(5 citation statements)

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“…The geometrically optimized, para-hydrogen tube moderator will deliver an order-ofmagnitude higher peak brightness than the corresponding moderator at the SNS FTS when that source operates at 2 MW and 60 Hz (Graves, 2017;Adams et al, 2020). The high brightness of the relatively small, 3 cm-diameter viewing area of the tube moderator is better suited for using focusing optics than the larger 10 � 12 cm viewing area of the FTS moderators (Lu et al, 2011).…”

Section: Basic Instrument Components and Layoutmentioning

confidence: 99%

A science-driven approach to optimize the design for a biological small-angle neutron scattering instrument

Wildgruber,

Qian,

Chen

et al. 2024

J Appl Cryst

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Biological small-angle neutron scattering (SANS) instruments facilitate critical analysis of the structure and dynamics of complex biological systems. However, with the growth of experimental demands and the advances in optical systems design, a new neutron optical concept is necessary to overcome the limitations of current instruments. This work presents an approach to include experimental objectives (i.e. the science to be supported by a specific neutron scattering instrument) in the optimization of the neutron optical concept. The approach for a proposed SANS instrument at the Second Target Station of the Spallation Neutron Source at Oak Ridge National Laboratory, USA, is presented here. The instrument is simulated with the McStas software package. The optimization process is driven by an evolutionary algorithm using McStas output data, which are processed to calculate an objective function designed to quantify the expected performance of the simulated neutron optical configuration for the intended purpose. Each McStas simulation covers the complete instrument, from source to detector, including realistic sample scattering functions. This approach effectively navigates a high-dimensional parameter space that is otherwise intractable; it allows the design of next-generation SANS instruments to address specific scientific cases and has the potential to increase instrument performance compared with traditional design approaches.

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Section: Basic Instrument Components and Layoutmentioning

confidence: 99%

A science-driven approach to optimize the design for a biological small-angle neutron scattering instrument

Wildgruber,

Qian,

Chen

et al. 2024

J Appl Cryst

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show abstract

“…The SAC is used to calculate the activation of user samples after irradiation on any SNS beamline, and has been incorporated into the user proposal and sample handling process [2]. The SAC tool is a webpage that takes user inputs such as the choice of beamline, the mass, composition and area of the sample, irradiation time, decay time, etc.…”

Section: Sac Descriptionmentioning

confidence: 99%

“…SAPEU uses the user input file (supplied by SAC) along with the CINDER 90 cross section library, a file containing the SNS beamline neutron flux spectra, and other reference files containing information on radiotoxicity, 2 X 2 sodium iodide detector efficiency, atomic mass, and natural isotopic abundances to calculate the activation of a given sample, and to provide handling guidance for the sample. The algorithm SAPEU uses to calculate the sample activation stems from the transmutation theory that is outlined in Lu's paper [2]. In order to effectively employ this algorithm, SAPEU makes several assumptions in order to decrease the calculation time of the sample activation.…”

Section: Sac Descriptionmentioning

confidence: 99%

“…In order to effectively employ this algorithm, SAPEU makes several assumptions in order to decrease the calculation time of the sample activation. SAPEU assumes that there is a constant flux over time and over the sample volume, constant sample atom number, and no neutron reactions for the daughter of the direct activation productions [2]. SAC assumes irradiation for a single energy (wavelength) band at a single accelerator power level, for a large number of cycles between that power and zero power.…”

Section: Sac Descriptionmentioning

confidence: 99%

“…The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL) uses the Sample Activation Calculator (SAC) to calculate the activation of a sample after the sample has been exposed to the neutron beam in one of the SNS beamlines [1,2]. The SAC webpage takes user inputs (choice of beamline, the mass, composition and area of the sample, irradiation time, decay time, etc.)…”

Section: Introductionmentioning

confidence: 99%

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