| 摘要 |
PURPOSE:To enable a molecular beam flow, a molecular beam speed distribution, etc., to be measured with one type of chopper by adding information meaning an opening width to a slot shape itself or its surround and then allowing the slot width to be identified. CONSTITUTION:A chopper is formed in upper and lower symmetrical shape in reference to a rotary axis. A reference number which is obtained from a sensor 36 with a photodetector 36'' is smooth and amplified by a reference signal amplifier 17 and then differentiated by the use of a differential circuit 18. Since a differential value is proportional to a leading speed of a pulse, a width of the slot can be selected with a height corresponding to the slot width if a signal with a positive sign is checked at setting levels L1 and L2 of a reference signal discriminator 19 at a desired amplitude. The selected signal is given to a signal processing circuit 21 as a slot width signal. On the other hand, a molecular beam signal is detected by the use of a monitor 27, is amplified by a molecular beam signal amplifier 22, and then fed to a signal processing circuit 12. The obtained result is calculated and analyzed by the use of a calculator 24.
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