| 摘要 |
<p>A photodiode detector for measuring beam power, impingement position and size. The detector has pairs of electrodes positioned at peripheral edges of a resistive surface of the detector, and an additional electrode positioned in the center of the resistive layer. The peripheral electrodes measure total power and beam position, and the central electrode additionally enables measurement of beam size. The voltage detected on the central electrode, when normalized for the power of the incident beam, provides a measure of the beam size, since the larger the beam, the less the Ohmic voltage developed on the electrode relative to the peripheral electrodes. The normalization to the power of the incident beam can be performed against the total sum of the currents collected from the peripheral electrodes, this summed current being proportional to the incident power. The voltage developed on the central electrode is proportional to the reciprocal of the beam diameter.</p> |
