Beamline Description

The end-station has a data acquisition system developed by the FERMI controls group, in collaboration with the LDM staff. This system is integrated into the control system of the facility and is based on the TANGO control framework [1]. It features the facility to configure and control the acquisition hardware, which includes a CAEN digitizer, model VX1751, 1 GS s⁻¹(S: Sample, 10 bits) on eight channels, with up to 100 μs of acquisition per shot, and the camera for the VMI spectrometer.
Several trigger signals are necessary, for example to open the gas source valve or the shutter of the camera, to provide time zero for the TOF mass spectrometer, and for ancillary as well as future instrumentation. These signals are generated by the timing system that synchronizes the operation of the entire FEL and, in particular, arms the firing of a given FEL shot [2]. Trigger and pretrigger signals can be made available at dedicated distribution ports at each beamline: LDM has 12 such ports. An arbitrary amount of delay can be ADDED via user-accessible software panels to each channel separately.
Presently the acquired data include the VMI image, the digitized traces from the TOF mass spectrometer, all end-station parameters like pressure and voltages, as well as a few machine parameters like the photon spectrum and the shot intensity (both from the PADReS diagnostics). The user can select what data is to be stored for the specific experiment. The acquisition system is flexible and other instruments can be added as long as a real-time TANGO driver is available.
The acquired data can be analysed almost in real-time (with a delay of a few seconds, depending on acquisition settings) by a fully configurable pre-processing engine that can apply user-defined algorithms and return the results via the TANGO system, so that they can be displayed while the acquisition is still running. The acquired data is stored using the HDF format [3] in a central storage server and can be directly accessed through the local network for further analysis a few minutes after the acquisition is done.

[1] www.tango-controls.org
[2] Ferianis M. et al., Proc. 33rd Int. Free Electron Laser Conf.
[3] www.hdfgroup.org