TOF Device Best Practices

Related links: SR620 best practices

Below are the BEST practices that are general and applicable to any time of flight device (time interval count or event timer) used for SLR/LLR applications:

1. Signal integrity:
1. Use only high-quality cables and connectors.
2. Take great care with shielding and grounding (earthing) in order to make sure that all noise sources are minimized.
2. External frequency ("Clock source"):
1. Supply each timer with a separate, high quality 5 or 10 MHz sine wave;
2. Make sure that the timer is set up to take an external "clock source"
3. Power supply:
1. Never switch off. If the timer has been switched off for any reason, allow adequate warm up before any operational use. Please refer to the manufacturer's operations manual for more information.
2. Use a stable mains voltage supply (for this and many other instruments it is useful to monitor the mains voltage regularly and warn when it falls).
3. Use a transient suppressor to prevent voltage "spikes" reaching the timer.
4. Environmental Control:
1. Maintain a stable working environment around the timer.
2. Keeping the temperature constant is particularly important.
3. Monitoring the temperatures of air at the timer air inlet and air outlet will give quick feedback of potential problems;
4. Maintain a good airflow around and through the instrument.
5. Be aware that nearby air-conditioning units, cycling on and off, can substantially alter the temperature of the air in the vicinity of the timer, even in a supposedly temperature stabilized room.
5. Non-linearity/timer calibration:
1. For picosecond event timers perform optical calibration as recommended by the manufacturer.
2. For time interval counters, either cluster the time interval units to help "average" non-linearities or calibrate each device versus a picosecond event timer and model any errors in data processing.
6. Jitter:
1. Monitor the jitter of the timer at least monthly.

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Last modified date: Friday, November 05, 2004
Author: Carey Noll
Maintained by: Carey Noll