The National Institute of Standards and Technology has recently begun a program to develop a primary pressure standard that is based on ultra-cold atoms, covering a pressure range of 1 × 10-6 Pa to 1 × 10-10 Pa and possibly lower. These pressures correspond to the entire ultra-high vacuum (UHV) range and extend into the extreme-high vacuum (XHV). This cold-atom vacuum standard (CAVS) is both a primary standard and absolute sensor of vacuum. The CAVS is based on the loss of cold, sensor atoms (such as the alkali-metal lithium) from a magnetic trap due to collisions with the background gas (primarily H2) in the vacuum. The pressure is determined from a thermally-averaged collision cross section, which is a fundamental atomic property, and the measured loss rate. The CAVS is primary because it will use collision cross sections determined from ab initio calculations for the Li + H2 system. Primary traceability is transferred to other systems of interest using sensitivity coefficients.

中文翻译：

---

制定新的 UHV/XHV 压力标准（冷原子真空标准）

美国国家标准与技术研究院最近开始了一项计划，以开发基于超冷原子的主要压力标准，涵盖 1 × 10-6 Pa 至 1 × 10-10 Pa 甚至更低的压力范围。这些压力对应于整个超高真空 (UHV) 范围并延伸到极高真空 (XHV)。这种冷原子真空标准 (CAVS) 是真空的主要标准和绝对传感器。CAVS 基于与真空中的背景气体（主要是 H2）碰撞而从磁阱中损失冷的传感器原子（例如碱金属锂）。压力由热平均碰撞截面（基本原子特性）和测得的损失率确定。CAVS 是主要的，因为它将使用由 Li + H2 系统的从头计算确定的碰撞横截面。使用灵敏度系数将主要可追溯性转移到其他感兴趣的系统。