本文件描述了表征具有电子碰撞电离离子源的四极杆质谱仪（QMS）的程序，所述四极杆质谱仪设计用于测量原子质荷比m/z<300。 本文件不适用于具有其他离子源（如化学电离、光电离或场电离源）的QMS，也不适用于主要用于指定有机材料的较高m/z的测量。 从已发表的关于四极杆质谱仪计量特性的研究中众所周知，它们的分压指示显著地取决于仪器的设置、总压力和气体混合物的组成。因此，不可能为所有可能的用途校准四极质谱仪。本文件中描述的表征程序涵盖了真空系统的连续泄漏监测、用示踪气体测量泄漏率、残余气体分析和除气率测量的应用。用户可以选择最适合他或她的需要的表征程序。这些表征程序也可用于其它应用。 还众所周知，四极质谱仪的几个参数的稳定性，特别是灵敏度，相当差。因此，当参数已经被校准时，当需要精度时，它需要频繁地重新校准。出于实际原因，这只能通过原位校准来实现。为此，本文件不仅描述了如何由校准实验室或国家计量研究所校准四极质谱仪，并直接追溯到国际系统(SI)，而且还描述了如何频繁检查校准的参数d并保持在原位。 根据其物理原理，四极杆质谱仪需要仪器内的高真空。通过减小尺寸或通过与差分泵浦相结合的特殊离子源，操作范围可以扩展到更高的压力，高达大气压。然而，该文献不包括具有差分泵送技术的四极杆质谱仪。因此，它不涵盖四极质谱仪入口法兰上超过1Pa的压力。 本文件未描述制造商或制造商订购的服务应如何对四极杆质谱仪进行初始调整。这种初始调整的目的主要是提供正确的m/z标度、恒定的质量分辨率或恒定的透射率，并且对于仪器来说是非常具体的。相反，本文档假设存在可由用户现场执行的制造商重新调整程序。该程序旨在确保四极杆质谱仪处于明确的表征条件下。 本文件的目的是让用户从他的四极杆质谱仪获得尽可能好的计量质量。从研究中已知，在大多数情况下，这可以在所谓的“扫描模式”中实现。取决于用于评估由四极质谱仪获取的数据的软件，条形图也可以具有足够的质量。然而，趋势模式通常涉及额外的不确定性，即峰值位置在质量标度上的移动导致离子电流的移动。因此，对于本文档的大多数测量过程，扫描模式是优选的。 本文件的意图不是为每个四极杆质谱仪确定所描述的所有参数。然而，如果给出或测量（例如用于检查测试），则本文中提及的参数的值应根据本文中描述的程序来确定。 本文件假设申请人熟悉四极杆质谱仪的操作以及高真空和超高真空技术。

This document describes procedures to characterize quadrupole mass spectrometers (QMSs) with an ion source of electron impact ionization and which are designed for the measurement of atomic mass-to-charge ratios m/z < 300. This document is not applicable to QMSs with other ion sources, such as chemical ionization, photo-ionization or field ionization sources and for the measurements of higher m/z, which are mainly used to specify organic materials. It is well known from published investigations on the metrological characteristics of quadrupole mass spectrometers that their indications of partial pressures depend significantly on the settings of the instrument, the total pressure, and the composition of the gas mixture. For this reason, it is not possible to calibrate a quadrupole mass spectrometer for all possible kinds of use. The characterization procedures described in this document cover the applications of continuous leak monitoring of a vacuum system, leak rate measurement with tracer gas, residual gas analysis and outgassing rate measurements. The user can select that characterization procedure that best suits his or her needs. These characterization procedures can also be useful for other applications. It is also well known that the stability of several parameters of quadrupole mass spectrometers, in particular sensitivity, are rather poor. Therefore, when a parameter has been calibrated, it needs frequent recalibration when accuracy is required. For practical reasons this can only be accomplished by in situ calibrations. To this end, this document not only describes how a quadrupole mass spectrometer can be calibrated by a calibration laboratory or a National Metrological Institute with direct traceability to the System International (SI), but also how calibrated parameters can be frequently checked and maintained in situ. By their physical principle, quadrupole mass spectrometers need high vacuum within the instrument. By reducing dimensions or by special ion sources combined with differential pumping the operational range can be extended to higher pressures, up to atmospheric pressure. This document, however, does not include quadrupole mass spectrometers with differential pumping technology. Therefore, it does not cover pressures exceeding 1 Pa on the inlet flange of the quadrupole mass spectrometer. This document does not describe how the initial adjustment of a quadrupole mass spectrometer by the manufacturer or by a service given order by the manufacturer should be made. The purpose of such an initial adjustment is mainly to provide a correct m/z scale, constant mass resolution or constant transmission, and is very specific to the instrument. Instead, it is assumed for this document that a manufacturer's readjustment procedure exists which can be carried on-site by a user. This procedure is intended to ensure that the quadrupole mass spectrometer is in a well-defined condition for the characterization. It is the intention of this document that the user gets the best possible metrological quality from his quadrupole mass spectrometer. From investigations it is known that in most cases this can be achieved in the so called "scan mode". The bar graph may also be of an adequate quality depending on the software used for evaluation of the data taken by the quadrupole mass spectrometer. The trend mode, however, often involves the additional uncertainty that a shift of the peak value position on the mass scale causes a shift in ion current. For this reason, the scan mode is preferable for most of the measurement procedures of this document. It is not the intent of this document that all the parameters described be determined for each quadrupole mass spectrometer. However, it is intended that the value of a parameter addressed in this document be determined according to the procedure described in this document if it is given or measured (e.g. for an inspection test). It is assumed for this document that the applicant is familiar with both the operation of quadrupole mass spectrometers and high and ultra-high vacuum technology.