HydraHarp400

To control the HydraHarp400 a controller and a device server is needed.

Some remarks:

• The acquisition mode is a property to the controller.

• The HydraHarp Windows application provided by PicoQuant is available in a docker container.

• The application convertT2T3ToAscii converts T2 and T3 output to an Ascii file.

• A CFD-based timing is done by detecting a zero crossing of a sum signal. Setting the zero cross level slightly above 0, reduces the noise level. This depends on the signal.

• The HydraHarp400 works in the forward start-stop mode. This is possible because there is a programmable divider in front of the sync input. This way the input rate can be reduced to match the dead time. The sync divider must not be used with slow synv sources < 1 MHz and also not for coincidence correlation experiments.

• The FiFo, used in T2 and T3 mode, has a size of 2 M event records, i.e. 8 MB:

• The TDC speed is 12.5 Mcps.

• Event record:
  • T2: 25b (timetag), 6b channel, 1b special (or sync, if channel==0)

  • T3: 15b (dtime) to encode the delay from the last sync in units of the the chosen resolution, 10b (nsync) for the sync counter: 10b nsync for the sync counter, 15b dtime to encode the delay from the last sync in units of the the chosen resolution, 6b channel, 1b special