08 April 2024 // Attila 10.3 Feature Spotlight KCODE

The third sportlight is: Attila4MC now supports KCODE calculations with the MCNP6 Unstructured mesh! We have added the capability to perform criticality calculations via the Attila4MC GUI providing an intuitive interface to mesh the geometry, check fidelity against the CAD model with mesh analytics, and execute calculations.

28 February 2024 // Attila 10.3 Upcoming New Features

The second spotlight is our new biased quadrature set generator (DOMO), which can be used to improve and accelerate the assessment of streaming gap and "dog leg" type penetrations in radiation shielding that are commonplace in modern neutronics models.

22 February 2024 // Attila 10.3 Upcoming New Features

Ahead of release of Attila 10.3 we are highlighting some of the upcoming features and updates users can expect. The first spotlight is enhanced solution visualisation.

13 February 2024 // Upcoming LANL Training Course: MCNP® unstructured Mesh with Attila4MCTM

Upcoming MCNP6 With Attila4MC Training at LANL on July 22-26, 2024

02 November 2023 // Silver Fir Software at the ANS Winter Meeting 2023

03 April 2023 // New Attila4MC Part-by-Part Mesh Generator

We are pleased to announce an OEM release of the new Attila4MC Part-by-Part Mesh generator, developed to simplify and automate mesh generation for complex CAD assemblies.

An OEM release (OEM 7) is now available for download and testing at www.attilasupport.com. To access, after login select Downloads then Part-by-Part Mesh Generator. This page contains a product overview, installation files, getting started instructions and tutorial examples.

27 February 2023 // Silver Fir Software at SFRP: Computer codes in radiation protection

Silver Fir Software will be exhibiting at the French Society of Radiation Protection (SFRP) Conference in Paris, France on March 9-10, 2023.

For more details about the conference, visit the SFRP-2023 website. Come visit us!

31 August 2022 // Silver Fir Software at ICRS-14/RPSD 2022

Come visit us at ICRS-14/RPSD-2022 in Seattle, WA on September 25-29, 2022. We will be holding a hands-on Attila4MC/Attila workshop on Sunday, September, 25th, where we will be demonstrating new and upcoming features, and will also be exhibiting at the conference. We look forward to seeing you there!

For more details about the conference, visit the ICRS-14/RPSD 2022 website

28 July 2022 // Attila4MC Reactor Pressure Vessel Fluence Case

This example assessed both neutron and secondary gamma fluence from a watt fission source in a reactor pressure vessel. The pressure vessel CAD model was imported directly into the Attila4MC GUI, allowing for unstructured mesh generation for both deterministic variance reduction (VR) and radiation transport.

SFSW-FENDL3.1d cross sections were used for the deterministic VR, allowing for 53 neutron groups and 42 gamma groups.

FW-CADIS calculations were run for the neutron and secondary gamma calculations using our bespoke deterministic VR solver method LDAS to achieve uniform uncertainty throughout the geometry. Neutron calculations were run for 1E+08 particles in MCNP, and secondary gamma calculations were run for 5E+07 particles in MCNP. For comparison both cases were also run in analog MCNP.

Total variance reduction run times were 78 minutes and 37 minutes for neutrons and secondary gammas respectively.

12 May 2022 // PHYSOR 2022

Silver Fir Software are pleased to announce we will be exhibiting at the International Conference on Physics of Reactors (PHYSOR) 2022 on May 15-20, in Pittsburgh. Come and meet the team at Table #9 to talk about how Attila4MC could support your radiation transport workflows, and hear about our exciting developments coming this year!

For more details about the conference, visit the PHYSOR 2022 website

14 Mar 2022 // Jonathan Rogers

We are pleased to announce that Jonathan Rogers has joined the Silver Fir Software team with the title of Business Development and Technical Support Engineer. Jonathan previously worked at Atkins in the UK, and he brings valuable expertise in radiation shielding and nuclear safety analyses using a variety of codes including Attila4MC, Attila®, and MCNP®. He also has scripting and development expertise and will be contributing to ongoing development of the Silver Fir Software product suite. Jonathan will be a valuable addition to Silver Fir Software, and we look forward to working together with him.

11 Feb 2022 // Waste Management Symposia 2022

Silver Fir Software are excited to announce we will be attending Waste Management 2022 in the Kinectrics Booth (#622) on March 6-10, 2022 in Phoenix, AZ . Several papers will be presented on the use of Attila4MC for spent fuel applications. We Attila4MC workshop will be held on Sunday, March 6th from 9:30-12:30. Workshop attendees will learn how to perform MCNP calculations using Attila4MC, with an emphasis on deep penetration shielding. Topics to be covered include importing a CAD assembly, setting up a calculation, performing weight windows variance reduction, and visualizing a calculated dose field. For more details, visit the WM 2022 website

14 Oct 2021 // New Release of Attila/Attila4MC 10.2.0

Silver Fir Software is pleased to announce the release of Attila/Attila4MC Version 10.2.0, which licensed users can download from www.attilasupport.com

Version 10.2.0 contains a number of features to significantly improve user productivity for both Attila and MCNP® calculations, some of which include:

  • Integration of the PNNL material database for radiation transport modeling (PNNL-15870r1) into the Attila/Attila4MC graphical user interface;
  • New adaptive spatial discretization method (LDAS) for improved weight window variance reduction efficiency using the CADIS and FW-CADIS methods;
  • 10-20% faster deterministic calculation efficiency;
  • Improved mesh generation robustness, including CAD interference tolerant modular mesh generation for MCNP®;
  • New FENDL-3.1d (n-γ) cross section library, with an inclusive list of isotopes, supporting both Attila and MCNP®;
  • Expanded command-line mesh generation/translation capabilities;
  • Ability to join results from independent calculations for Tecplot® solution visualization;
  • New videos training content in support of Version 10.2 including: optimizing of CADIS and FW-CADIS, walking over small CAD features in mesh generation, solution merging, and basic tutorials, etc.

For more information, please contact us at support@silverfirsoftware.com

24 Aug 2021 // Attila4MC High Energy Physics Example – Proton Therapy Center.

This example assessed both neutron and secondary gamma dose from a 250 MeV proton source.

The facility CAD model was imported directly into the Attila4MC GUI, allowing for unstructured mesh generation for both deterministic variance reduction (VR) and radiation transport.

HILO2K cross sections were used for the deterministic VR, allowing for neutron energies up to 2 GeV.

For comparison cases were run in analog MCNP, and with our deterministic VR solver LDAS with FW-CADIS to achieve uniform uncertainty throughout the facility.

All models were run for 1E+08 particles, variance reduction run times were 30 minutes and 13 minutes for neutrons and secondary gammas respectively.

If you would like to hear more about how our products can improve your efficiency with MCNP, please contact us on LinkedIn:


24 Aug 2021 // Attila4MC High Energy Physics Example – Proton Therapy Center.

3 Aug 2021 // Silver Fir Software Inc. and Kinectrics Inc. have signed a cooperation agreement that will establish Kinectrics as a preferred training partner and user of the Attila code suite for the North American nuclear industry.

“Kinectrics is excited to work with Silver Fir Software to advance the use of Attila in the North American nuclear industry”, said David Harris, President and CEO of Kinectrics.

Read more about this exciting new initiative here: https://lnkd.in/eMVGFWw

20 July 2021 // Silver Fir Software are delighted to announce we have been awarded a Phase I Small Business Innovation Research (SBIR) Grant from the U.S. Department of Energy Fusion Energy Sciences Program.

The Grant, titled “Design Focused Product to Streamline Fusion Neutronics Calculation Workflow” will expand the capabilities of Attila4MC in support of Fusion Neutronics applications. As part of this project, Silver Fir Software will further simplify the Attila4MC process to generate an MCNP® computational model from CAD assemblies, with an emphasis on eliminating the need for users to remove insignificant part overlaps, which are common in production CAD assemblies.

A secondary emphasis of the project is to expand Attila4MC features related to activation source generation on the tetrahedral mesh. The Massachusetts Institute of Technology Plasma Science and Fusion Center will be participating as a subcontractor on this grant, and will be testing developed features on relevant SPARC tokamak models. Although the initial emphasis is on MCNP integration, the capabilities developed under this project will later be extended to support the OpenMC Monte Carlo code.

29 June 2021 // Introducing LDAS – Our new deterministic variance reduction solver, which generates energy based weight windows for MCNP.

The example below produces a deterministic solution for a 1E+15 reduction in the flux field in under two minutes. Providing a quick solution to your variance reduction needs. If you want to hear more about how LDAS could improve your MCNP productivity, or any of our other products, please get in touch with one of our support team.

11 May 2021 // We at Silver Fir Software are delighted to announce our expansion with the opening of a UK & Europe branch, further strengthening our support and services offerings to our clients.

This branch will be headed up by Andrew Cooper, who joins us from Atkins, and will be based in the UK. Andrew brings with him a wealth of experience in the nuclear consulting sector with 15 years specializing in radiation transport analysis and business development for a variety of clients in the UK and abroad. As Director of the UK & Europe branch, Andrew will be responsible for Business Development and Technical Support, where his knowledge of the nuclear sector and experience with industry standard analysis codes such as MCNP and Attila will be a valuable asset to the Silver Fir Software business.

11 Feb 2021 // Check out the recently updated Publications section of our website!

We’ve collected an extensive list of third-party technical reports and peer-reviewed publications, including radiation transport on unstructured mesh specific publications. We will be constantly updating this page; let us know if we’ve missed anything!

14 Dec 2020 // We are pleased to announce that we released Attila 10.2.0-beta3 on November 25th, 2020.

Attila 10.2.0-beta3 introduces the new Linear Discontinuous Adaptive to Step (LDAS*) spatial discretization, applicable for CADIS and FW-CADIS calculations with Attila4MC. LDAS is a new proprietary adaptive spatial discretization scheme that eliminates the possibility of negative flux solutions, other than those resulting from negative scattering sources, while retaining high accuracy through thick shields. LDAS can produce an accurate and smooth weight windows file for MCNP®, improving solution convergence rates. Also included in 10.2.0-beta3 is the Reprise License Manager, which provides a server based floating license capability. Attila 10.2 is scheduled for release early 2021. *Patent pending

15 Aug 2020 // Welcome to our new website!

04 May 2020 // We are currently testing Attila 10.2.0-beta2, released on May 4th, 2020.

This latest beta includes an updated mesher to improve robustness and parasolid compatibility.

07 Jan 2020 // An “adjoint grid flux correction” capability was added into Attila 10.2.0-beta1

This is done to smooth weight windows for problems with significant ray effects, substantially improving performance for CADIS and FW-CADIS calculations.