Measurement Synchronization with Cold Head Frequency
The Sync Pulse Modification Kit is an optional add-on for the system which provides users the ability to take measurements when the cryocooler is in the quietest portion of the pulse cycle. This feature helps to reduce vibrations beyond the specified peak-to-peak values for even better stability during a measurement. This feature is targeted for users who do not need to take continuous measurements. Inclusion of this modification must be made during the initial build of the system. Please consult with your sales representative for details.
There is a Hall probe sensor (MP1021 series sensor) which is placed at the top of the cold head. On the top of the displacer there is a small magnet and when in line with the Hall probe sensor this triggers the pulse on. To access the cold head cycle, plug a BNC into SYNC at the back of the control unit as shown in the white box of the figure below.
The vibrations are lowest when the SYNC pulse is high, so users can trigger to the pulse as it transitions to high. The cycle runs between 1-2Hz, depending on what speed the compressor is running at.