Molflow+ is a Monte Carlo (MC) simulation software for ultra-high vacuum, mainly used to simulate pressure in particle accelerators. In this article, we present and discuss the design choices arising in a new implementation of its ray-tracing–based simulation unit for Nvidia RTX Graphics Processing Units (GPUs). The GPU simulation kernel was designed with Nvidia’s OptiX 7 API to make use of modern hardware-accelerated ray-tracing units, found in recent RTX series GPUs based on the Turing and Ampere architectures. Even with the challenges posed by switching to 32 bit computations, our kernel runs much faster than on comparable CPUs at the expense of a marginal drop in calculation precision.

Molflow+ 是一款用于超高真空的蒙特卡罗 (MC) 模拟软件，主要用于模拟粒子加速器中的压力。在本文中，我们介绍并讨论了 Nvidia RTX 图形处理单元 (GPU) 的基于光线追踪的模拟单元的新实现中出现的设计选择。GPU 模拟内核是使用 Nvidia 的 OptiX 7 API 设计的，以利用现代硬件加速光线跟踪单元，这些单元在最近的基于图灵和安培架构的 RTX 系列 GPU 中找到。即使切换到 32 位计算带来了挑战，我们的内核运行速度也比同类 CPU 快得多，代价是计算精度略有下降。