公开(公告)号：US3821546A

公开(公告)日：1974-06-28

申请号：US31019372

申请日：1972-11-28

Applicant: NASA

Inventor： MC CLENAHAN J

IPC: H01J43/04 ,  H01J39/12

CPC classification number: H01J43/04

Abstract: A photomultiplier tube comprising a plurality of electrodes including a light sensitive cathode, an anode, and a plurality of dynodes positioned in space-apart manner along the electron beam path between the cathode and anode and having a power supply and a voltage divider for supplying bias voltages across each successive pair of electrodes along the beam path, at least one switching device being provided across a pair of said electrodes, preferably across the cathode and first dynode or across the first and second dynodes, which, when activated, will rapidly reduce the bias voltage across the associated pair of electrodes to near zero, thereby substantially reducing the sensitivity of the multiplier to protect it from the effects of excessive light intensity input. In a preferred embodiment of the invention, an SCR is coupled across the cathode and first dynode and is operated by a blanking or trigger pulse applied to its control gate to rapidly reduce the bias voltage across this first stage. Additional switching rectifiers may be employed across other stages of the multiplier to insure the desired reduction in sensitivity.

公开(公告)号：US3797919A

公开(公告)日：1974-03-19

申请号：US3797919D

申请日：1972-06-30

Applicant: NASA

Inventor： MC CLENAHAN J

IPC: G03B9/08 ,  G03B9/58 ,  H01J49/04 ,  G02F1/30

CPC classification number: G03B9/08 ,  G03B9/58

Abstract: A shutter element is formed by a loop of an electrically conductive ribbon disposed adjacent to the end of a passageway to be shuttered. The shuttered end of the passageway is cut at an acute angle. The two leg portions of the ribbon loop are closely spaced to each other and disposed in a plane parallel to the axis of the passageway. A pulse of high current is switched through the loop to cause the current flowing in opposite directions through adjacent leg portions of the ribbon to produce a magnetically induced pressure on one of the legs of the ribbon forcing the leg over the end of the passageway in gas tight sealing engagement therewith, thereby blocking same.

Abstract translation: 快门元件由邻近待关闭通道的端部设置的导电带的环形成。 通道的快门端部以锐角切割。 色带环的两个腿部彼此紧密间隔并且设置在与通道的轴线平行的平面中。 大电流脉冲通过环路切换，使电流沿相反的方向流过色带的相邻腿部，从而在色带的一条腿上产生磁力感应压力，迫使腿部气体在气体通道的末端 与其紧密地密封接合，从而阻挡它们。