ATTOTECH GR020 매뉴얼 - 페이지 11

{카테고리_이름} ATTOTECH GR020에 대한 매뉴얼을 온라인으로 검색하거나 PDF를 다운로드하세요. ATTOTECH GR020 16 페이지. Piezo driven pulsed valve

At 5 Bars backing pressure, the negative operating voltage must not exceed -350 V. In the

following never turn up the voltage above that limit. It corresponds to an indication of 350

on the Peak voltage indicator (#2).



Connect the low voltage signal to the high voltage amplifier by switching (#5) on.



Progressively increase the negative voltage driving the valve until you see the pressure in

your experimental chamber rising. It should be noted that the opening is not linear: the

valve stays closed up to a certain threshold (called hereafter the opening voltage) after

which the amount of gas sent in the target increases rapidly with the voltage. Be careful

when approaching the typical opening voltages given in the table in the "specifications"

section.

Once the right amount of gas is set, you should let it run for approximately 15 minutes to reach

a thermal steady state. During this time, it might be necessary to slightly readjust the voltage (#4).

Scan the delay controlling when the valve starts to open to find temporal overlap of the released

gas and your laser.

Turning off



Turn down the driving voltage (#4).



Turn off switch #5.



Turn off the electrical power (switch #1).



Close the cooling and close the backing gas bottle.

Settings

The gas flow when the valve is open is dependent on the backing pressure. Stable operation of

the pulsed valve requires the backing pressure inside the valve body to be well regulated.

Several settings of the high voltage, the duration of the gate (T

result in comparable gas dynamics. For instance at a given backing pressure increasing the

opening gate and reducing the high voltage result in the same mechanical opening time

The mechanical design is made to preserve the alignment when switching targets. Target change

is straightforward; unscrew the two M3 screws (no. 7) and carefully remove the target. Check that

the O-ring no. 9 is still in position and mount the new target. The guiding pins (no. 8) and the

screws define the position of the target, only very slight readjustments of the valve position might

be needed to maximize your signal after target replacement.

To keep your valve in a good working condition, we recommend you reading the last section of

the "piezo actuators tutorial" available from

http://www.physikinstrumente.com/en/pdf_extra/PI_designing_with%20piezo_actuators_tutorial_2

005c.pdf

In the tutorial you will find information how to calculate the best combination of opening gate and

high voltage.

-T

) and the backing pressure