Results from SR timer comparisons at Herstmonceux Workshop


SR timer comparison results

As part of the Eurolas workshop at Herstmonceux, stations were asked to bring their SR620 timers along to compare with the Hx timer. The Hx timer has been compared with both HP5370B timers and the PPET (portable pico- second event timer) and has shown no range dependent errors.

For the tests carried out at Herstmonceux we tried to ensure the following standard conditions

- All SRs had an external 10 Mhz frequency

- The temperature was stable for each timer. This required "warming" it up for an hour. During the hour tests were carried out and these gave significantly different readings from the subsequent tests.

- The threshold settings used are the same and are set by software and not the the front panel

- The configuration for the test is exactly the same as for normal observing. ie the start pulse comes from the laser start diode and the stop pulse comes from our C-SPAD detector

Shown below are the results of comparison tests made between the Herstmonceux SR timer and SR timers from Borowiec,Potsdam,San Fernando and Zimmerwald.

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