Flaxer Eli
AFEKA-Tel-Aviv Academic College of Engineering, Tel-Aviv, Israel.
Rev Sci Instrum. 2011 Feb;82(2):025111. doi: 10.1063/1.3555340.
In electron ionization source, electrons are produced through thermionic emission by heating a wire filament, accelerating the electrons by high voltage, and ionizing the analyzed molecules. In such a system, one important parameter is the filament emission current that determines the ionization rate; therefore, one needs to regulate this current. On the one hand, fast responses control is needed to keep the emission current constant, but on the other hand, we need to protect the filament from damage that occurs by large filaments current transients and overheating. To control our filament current and emission current, we developed a digital circuit based on a digital signal processing controller that has several modes of operation. We used a smart algorithm that has a fast response to a small signal and a slow response to a large signal. In addition, we have several protective measures that prevent the current from reaching unsafe values.
在电子电离源中，通过加热金属丝灯丝产生热电子发射，用高电压加速电子，并使被分析分子电离。在这样一个系统中，一个重要参数是决定电离速率的灯丝发射电流；因此，需要调节该电流。一方面，需要快速响应控制以保持发射电流恒定，但另一方面，我们需要保护灯丝免受因大的灯丝电流瞬变和过热而导致的损坏。为了控制我们的灯丝电流和发射电流，我们基于具有多种操作模式的数字信号处理控制器开发了一种数字电路。我们使用了一种智能算法，该算法对小信号响应快，对大信号响应慢。此外，我们还有几种保护措施，可防止电流达到不安全值。
