Medical physicists use a suitable detector connected to an electrometer to measure radiotherapy beams. Each detector and electrometer has a lifetime (due to physical deterioration of detector components and electrical characteristic deterioration in electronic electrometer components), long-term stability [according to IEC 60731:2011, ≤0.5% (reference-class dosimeter)], and calibration frequency [according to Muir et al. (J Appl Clin Med Phys. 2017; 18:182-190), generally 2 years]; thus, physicists should check the electrometer and detector separately. However, to the best of our knowledge, only one study (Blad et al., Phys Med Biol. 1998; 43:2385–2391) has reported checking the electrometer independently from the detector. The present study conducts performance checks on electrometers separately from the detector in clinical settings, using an electrometer equipped with a direct current (DC) generator (EMF 521R) capable of injecting DC (effective range: ±20 pA to ±20 nA) into itself or another electrometer.

中文翻译：

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在诊所使用直流发电机检查静电计性能检查：产生电荷的评估和静电计检查的实施

医学物理学家使用连接到静电计的合适检测器来测量放射治疗束。每个探测器和静电计都有使用寿命（由于探测器组件的物理退化和电子静电计组件的电气特性退化）、长期稳定性 [根据 IEC 60731:2011，≤0.5%（参考级剂量计）] 和校准频率 [根据 Muir 等人的说法。(J Appl Clin Med Phys. 2017; 18:182-190)，一般为 2 年]；因此，物理学家应分别检查静电计和探测器。然而，据我们所知，只有一项研究（Blad 等人，Phys Med Biol. 1998年；43:2385–239​​1) 报道了独立于检测器检查静电计。本研究使用配备直流 (DC) 发生器 (EMF 521R) 的静电计在临床环境中与检测器分开对静电计进行性能检查，该静电计能够将直流电（有效范围：±20 pA 至 ±20 nA）注入自身或其他静电计。