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SpecTcl is the NSCL's event data analysis tool used for online and offline data analysis during experiments involving the S800 spectrograph. The documentation is accessible at: http://docs.nscl.msu.edu/daq/spectcl/
The SpecTcl Control has been adapted for special functions required for the analysis of S800 data. Fig xxx shows the GUI control of the S800 analysis.
The inverse map which enables the trajectory reconstruction of the particles within the spectrograph beam line can be loaded. Snapshots of CRDC and TPPAC events sampled in the pads and strips can be viewed. If this option is “armed”, the sample is read out for the first event that falls into the specified gate. This is a diagnostics tool to analyze the response of the CRDCs and TPPACs.
The TreeParameter class provides a mean to implement parameters in SpecTcl in a tree-like structure and without the need to specify parameter identification numbers. The parameters are referred to by their names only, which at the same time indicate their location in the tree. This reference mechanism is valid for both the coding part of SpecTcl (C++ code) and the interpreter part (Tcl/Tk shell). It eliminates the confusion induced by the use of numerals to refer to the parameters, and allows the user to organize the parameters in a logical fashion.
Important Variables (to be set on the “Variables” page of the GUI) for the CRDCs (n=1,2 for crdc1 and crdc2): • s800.fp.crdcn o .x_offset: offset in the x calibration, chosen to center the “beam hole” (see mask calibration) at 0 mm. o .x_slope: the slope of the x calibration. This value is always 2.54 mm/pad since the geometry of the pads inside the CRDCs is fixed o .y_offset: y offset in mm to be determined from the mask calibration o .y_slope: y slope in mm/ns to be determined from the mask calibration
• s800.fp.crdcn.calc o .method: 1 sets “center of gravity” as method to determine the x position from the charge distribution in the pads, 2 enables the usage of the fit method o .gravity_width: sets the number of pads used to determine the center of gravity o .fit_width: number of pads taken for the Gaussian fit o .badpads: total number of pads declared as “bad” (see point below) o .badpad.mm: declares pad no. mm as “bad pad” and removes it from the calculation that determines the x position
• s800.fp.track o .order: sets the order to which the reconstruction (inverse map) will be performed (typically 5th order) o .map.maxorder: determined by the inverse map. The maximum order is typically 5 and set automatically as soon as the inverse map is sourced in SpecTcl o anglea and angleb: offset in angle (dispersive and non-dispersive) of the incoming beam hitting the target. The reconstruction assumes a beam without initial angles. The variables anglea and angleb have to be adjusted to center the angle distribution in the spectrum “bta vs. ata” so that the incoming angles are accounted for in the reconstruction
• s800.tof o objCorrection, obje1Correction, obje2Correction: corrections applied to the TOF measured between the object scintillator and the trigger scintillator. Details of the corrections will change from experiment to experiment and are accessible via the CS800.cpp file of the S800 SpecTcl source code o xfpCorrection, xfpe1Correction, xfpe2Correction: corrections applied to the TOF measured between the extended focal plane scintillator (A1900) and the trigger scintillator. Details of the corrections will change from experiment to experiment and are accessible via the CS800.cpp file of the S800 SpecTcl source code