There exists on optimal value of magnetic focusing field and beamvoltage, which can minimize the ion noise amplitude.
束电流与束电压确定，存在最佳的磁场使离子噪声幅度最小。
2
After the connections are made, verify the system is working properly by turning the bias voltage on and taking a current measurement with no ion beam current.
完成电路连接之后，接通偏置电压，在没有离子束电流的情况下进行电流测量，以验证系统能够正常工作。
3
Cantilever beam holding object is controlled through changing direction of voltage applied. When the voltage is zero, release the object.