JCosmixerDepp

JCosmixerDepp is the configuration interface for the scintillator coincidences. It can be started from the JRichTBTrigger GUI.

Software Installation

General installation instructions can be found in the RichEcKit topic.

Hardware

The JCosmixerDepp functions are supported by a hardware plugin that connects to the trigger board via the Tengja adapter. The plugin provides 4 independent channels with programmable threshold and selectable gain. The inputs are 50 Ohm terminated to ground and compatible with the outputs of typical photomultipliers.

There is one switch and one header for each channel on the plug-in. The gain can be selected to be 1 or 5 by the switch. The position is indicated by the markings G1 and G5 on the PCB. For typical photomultipliers, the G1 setting should be used. The jumper should always be placed in the position away from the corresponding LEMO connector.

Usage

JCosmixerDepp can form up to six coincidences using any combination of the four inputs. Any of these coincidences can be used as a trigger source in JRichTBTrigger. Each coincidence has a dedicated counter for monitoring.

The GUI should be started from the JRichTBTrigger GUI. This will open the main panel that allows the setting of the channel thresholds and the pulse width of the internally generated digital pulses. This panel also has a menu that allows the counter panel and coincidence set-up panel to be displayed.

Input streams

The threshold applied to each setting is expressed as the absolute value of the threshold in mV. Type the desired value in the editable text field and hit Enter. The conversion of the threshold values to the internal DAC values uses a linear relationship. The coefficients can be modified if necessary but not currently through the GUI.

The pulse width setting is intended to ensure an overlap of the individual inputs that form a coincidence without having to fine tune cable delays. For most systems, small integers like 1, 2 or 3 should be fine. Type the desired value into the editable text field and hit Enter.

Coincidences

To configure the coincidences, open the Main->Coincidence setup... panel. Select which input channels you want to contribute to each coincidence. Each coincidence is the logical AND of the selected inputs.

With care, it is possible to preserve the timing of a scintillator in the coincidence output so that the leading edge of the coincidence signal is synchronous with the scintillator. To achieve this, one scintillator should be designated as the timing reference and cable delays should be used to ensure that this scintillator is the last to be asserted. The trailing edge of the coincidence is always synchronous to the internal clock.

Counters

To view the coincidence counts, open the Main->Counters... panel.

-- StephenWotton - 2017-02-24

Edit | Attach | Watch | Print version | History: r2 < r1 | Backlinks | Raw View | WYSIWYG | More topic actions
Topic revision: r2 - 2017-05-09 - StephenWotton
 
    • Cern Search Icon Cern Search
    • TWiki Search Icon TWiki Search
    • Google Search Icon Google Search

    LHCb All webs login

This site is powered by the TWiki collaboration platform Powered by PerlCopyright & 2008-2019 by the contributing authors. All material on this collaboration platform is the property of the contributing authors.
Ideas, requests, problems regarding TWiki? Send feedback