# Fast Monte Carlo simulation of a dispersive sample on the SEQUOIA spectrometer at the SNS

## Abstract

Simulation of an inelastic scattering experiment, with a sample and a large pixilated detector, usually requires days of time because of finite processor speeds. We report simulations on an SNS (Spallation Neutron Source) instrument, SEQUOIA, that reduce the time to less than 2 hours by using parallelization and the resources of the TeraGrid. SEQUOIA is a fine resolution (∆E/Ei ~ 1%) chopper spectrometer under construction at the SNS. It utilizes incident energies from Ei = 20 meV to 2 eV and will have ~ 144,000 detector pixels covering 1.6 Sr of solid angle. The full spectrometer, including a 1-D dispersive sample, has been simulated using the Monte Carlo package McStas. This paper summarizes the method of parallelization for and results from these simulations. In addition, limitations of and proposed improvements to current analysis software will be discussed.

- Authors:

- ORNL

- Publication Date:

- Research Org.:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS); Center for Computational Sciences

- Sponsoring Org.:
- USDOE Office of Science (SC)

- OSTI Identifier:
- 931441

- DOE Contract Number:
- DE-AC05-00OR22725

- Resource Type:
- Conference

- Resource Relation:
- Conference: Workshop on Inelastic Neutron Spectrometers 2005, Cairns, Australia, 20061205, 20061206

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 43 PARTICLE ACCELERATORS; 97; NEUTRON SOURCES; NEUTRON SPECTROMETERS; RESOLUTION; COMPUTERIZED SIMULATION; SPALLATION; MONTE CARLO METHOD; INELASTIC SCATTERING; PARALLEL PROCESSING; Monte Carlo Simulations; Teragrid; Neutron; spectrometer

### Citation Formats

```
Granroth, Garrett E, Chen, Meili, Kohl, James Arthur, Hagen, Mark E, and Cobb, John W.
```*Fast Monte Carlo simulation of a dispersive sample on the SEQUOIA spectrometer at the SNS*. United States: N. p., 2007.
Web.

```
Granroth, Garrett E, Chen, Meili, Kohl, James Arthur, Hagen, Mark E, & Cobb, John W.
```*Fast Monte Carlo simulation of a dispersive sample on the SEQUOIA spectrometer at the SNS*. United States.

```
Granroth, Garrett E, Chen, Meili, Kohl, James Arthur, Hagen, Mark E, and Cobb, John W. Mon .
"Fast Monte Carlo simulation of a dispersive sample on the SEQUOIA spectrometer at the SNS". United States.
doi:.
```

```
@article{osti_931441,
```

title = {Fast Monte Carlo simulation of a dispersive sample on the SEQUOIA spectrometer at the SNS},

author = {Granroth, Garrett E and Chen, Meili and Kohl, James Arthur and Hagen, Mark E and Cobb, John W},

abstractNote = {Simulation of an inelastic scattering experiment, with a sample and a large pixilated detector, usually requires days of time because of finite processor speeds. We report simulations on an SNS (Spallation Neutron Source) instrument, SEQUOIA, that reduce the time to less than 2 hours by using parallelization and the resources of the TeraGrid. SEQUOIA is a fine resolution (∆E/Ei ~ 1%) chopper spectrometer under construction at the SNS. It utilizes incident energies from Ei = 20 meV to 2 eV and will have ~ 144,000 detector pixels covering 1.6 Sr of solid angle. The full spectrometer, including a 1-D dispersive sample, has been simulated using the Monte Carlo package McStas. This paper summarizes the method of parallelization for and results from these simulations. In addition, limitations of and proposed improvements to current analysis software will be discussed.},

doi = {},

journal = {},

number = ,

volume = ,

place = {United States},

year = {Mon Jan 01 00:00:00 EST 2007},

month = {Mon Jan 01 00:00:00 EST 2007}

}