Low-Energy Muon (LEM) Experiment  0.5.0
Introduction and Components
previous.gif main - Installation next.gif

The experiment runs under Scientific Linux SL5.1. The actual system is lem00, PSI-SL5.1, kernel 2.6.18-164.9.1.el5. For communication with VME a SIS1100/3100 VME-PCI interface is installed to readout two SIS3820 VME multi-scaler modules and a CAEN V1190 64-channel multi-hit TDC.

The frontend for VME readout is vme_fe.c which reads periodically every 3 sec the 64 channels of the two scaler modules; if a run is active the TDC V1190B, running in CONTINUOUS_STORAGE mode, is polled, and readout of the TDC's memory is executed if the ALMOST_FULL_BIT of the TDC is set. The frontend then tests all the TDC time data and searches for valid events, i.e. the trigger condition is now set up completely in software.

Currently there are several slow control frontends running:

  • bl_scfe.c for readout of the muE4 beamline, using the bl_psi.c device driver and the tcpip.c bus driver. The device driver was fixed to allow for correct reading and setting of beam line elements. The two device drivers bb_psi_kv61.c and bb_psi_kv62.c are for remote control of the two beam shutters KV61 and KV62. The driver separator61.c is for control of the electrostatic separatro SEP61.
  • to be continued...

Scaler rates and sums are calculated by the Midas analyzer analyzer.c. If a run is stopped it just calculated the detector rate that are displayed in the analyzer terminal window. Alternatively, they can be viewed on the Midas status web page if the Midas web server mhttpd is running. The analyzer writes a run log runlog.txt at end-of-run that can be viewed on the Midas status web page.

The analyzer consists of the modules analyzer.c, scaler_rate_sum.c, mcp1_ana_module.c, tof_ana_module.c, decay_ana_module.c, pileup_ana_module.c and sc_ana_module.c. The *_ana_*.c modules create root histograms that are filled online if a run is active. At end-of-run the root histograms are saved in /data/nemu/his/YYYY, where YYYY is the current year.

The Midas mlogger writes slow control parameters to the Midas history file (extension .hst), and - if a run is active - scaler and TDC data event-by-event to the data file in ROOT format (extension .root).

previous.gif main - Installation next.gif