PicoQuant GmbH HydraHarp 400 Software V. 3.0.0.1
6.4. Control Panel
The control panel consists of several pages (tabbed sheets) containing edit boxes and other controls for related
parameters. These pages are described in the following subsections. Note that the settings of the control panel
as well as the position of the control panel on the screen will be stored in the registry and retrieved at the next
program start. When you load a HydraHarp data file the settings of the control panel will change according to
the settings in that file. This can be used as a means of reverting to a standard setting for the given experiment.
6.4.1. Sync–Input
The settings in this group configure the behaviour of the Sync input. See section 5.1 “Setting Up the Input
Channels“ to get started.
Zero Cross edit box and spin control
Here the zero cross level of the Constant Fraction Discriminator (CFD) for the Sync input can be set. Units are
millivolts (mV), the permitted range is 0 to 40. Type the value as an integer in the edit box and press <Enter>
or click on Apply. Alternatively, use the spin control (next to it) to increment / decrement the current value. In
this case changes take effect immediately without pressing <Enter>.
Discriminator Level edit box and spin control
Here the discriminator level of the Constant Fraction Discriminator (CFD) for the Sync input can be set. Units
are millivolts (mV), the permitted range is 0 to 1,000. This corresponds to real input voltage levels of
0 to −1,000 mV. Type the value as an integer in the edit box and press <Enter> or click on Apply.
Alternatively, use the spin control (next to it) to increment / decrement the current value. In this case changes
take effect immediately without pressing <Enter>.
Offset edit box and spin control
Shifts the relative timing of Sync and photon events and is designed to compensate optical and electrical
delays (e.g. in cables and optical paths), e.g. in order to shift your fluorescence decay within the sync frame so
that it is not truncated. This feature completely eliminates the need for adjustable delay boxes.
Units are picoseconds (ps), the permitted range is from −99,999 ps to +99,999 ps. Type the value as an integer
in the edit box and press <Enter> or click on Apply. The offset value can be entered in steps of picoseconds.
Alternatively, use the spin control next to the edit box to increment ⁄ decrement the current value. In this case
changes take effect immediately without pressing <Enter>.
Sync Divider edit box and spin control
Here the programmable divider of the Sync input can be set. This allows to reduce the sync input rate so that
the period is at least as long as the dead time. This is required for fast sync sources (>12.5 MHz) Internal logic
determines the sync period and re–calculates the sync signals that were divided out. It must be noted that this
only works with stable sync sources that provide a constant pulse–to–pulse period, but all fast laser sources
known today meet this requirement within an error band of a few picoseconds. With random and low rate
signals (< 1 MHz), the divider must be set to 'None'.
6.4.2. Inputs 1…4
The settings in this group configure the behaviour of the input channels 1..4. See section 5.1 “Setting Up the
Input Channels“ to get started. The HydraHarp device is modular and can have up to 8 input channels. In order
to avoid excessive space requirements as well as unpleasant clutter in the controls for all those channnels,
they are organized in groups of 4. This page holds the controls for the input channels 1..4. If only two channels
are installed, only the control elements for channels 1..2 will be accessible. If more than 4 channels are
installed, the control elements of channels 5..8 will be located in a separate page of similar layout (see below).
The specific controls for each channel on this page are described below.
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