Index: trunk/MagicSoft/Mars/mhflux/MAlphaFitter.cc =================================================================== --- trunk/MagicSoft/Mars/mhflux/MAlphaFitter.cc (revision 7066) +++ trunk/MagicSoft/Mars/mhflux/MAlphaFitter.cc (revision 7091) @@ -357,7 +357,7 @@ case kEntries: *fLog << "entries."; break; case kIntegral: *fLog << "integral."; break; - case kOffRegion: *fLog << "off region."; break; - case kBackground: *fLog << "background."; break; - case kLeastSquare: *fLog << "least square."; break; + case kOffRegion: *fLog << "off region (intgeral between " << fScaleMin << " and " << fScaleMax << ")"; break; + case kBackground: *fLog << "background (integral between " << fBgMin << " and " << fBgMax << ")"; break; + case kLeastSquare: *fLog << "least square (N/A)"; break; case kUserScale: *fLog << "user def (" << fScaleUser << ")"; break; } Index: trunk/MagicSoft/Mars/mhflux/MHEffectiveOnTime.cc =================================================================== --- trunk/MagicSoft/Mars/mhflux/MHEffectiveOnTime.cc (revision 7066) +++ trunk/MagicSoft/Mars/mhflux/MHEffectiveOnTime.cc (revision 7091) @@ -75,4 +75,183 @@ // MTimeEffectiveOnTime [MTime] // +// +// ========================================================================== +// Dear Colleagues, +// +// for the case that we are taking calibration events interleaved with +// cosmics events the calculation of the effective observation time has to +// be modified. I have summarized the proposed procedures in the note at the +// end of this message. The formulas have been checked by a simulation. +// +// Comments are welcome. +// +// Regards, Wolfgang +// -------------------------------------------------------------------------- +// Wolfgang Wittek +// 2 Dec. 2004 +// +// Calculation of the effective observation time when cosmics and calibration +// events are taken simultaneously. +// -------------------------------- +// +// I. Introduction +// --------------- +// It is planned to take light calibration events (at a certain fixed frequency +// lambda_calib) interlaced with cosmics events. The advantages of this +// procedure are : +// +// - the pedestals, which would be determined from the cosmics, could be +// used for both the calibration and the cosmics events +// +// - because calibration and cosmics events are taken quasi simultaneously, +// rapid variations (in the order of a few minutes) of base lines and of the +// photon/ADC conversion factors could be recognized and taken into account +// +// The effective observation time T_eff is defined as that time range, within +// which the recorded number of events N_cosmics would be obtained under ideal +// conditions (only cosmics, no dead time, no calibration events, ...). +// +// In the absence of calibration events the effective observation time can +// be determined from the distribution of time differences 'dt' between +// successive cosmics events (see first figure in the attached ps file). +// The exponential slope 'lambda' of this distribution is the ideal cosmics +// event rate. If 'N_cosmics' is the total number of recorded cosmics events, +// T_eff is obtained by +// +// T_eff = N_cosmics / lambda +// +// In the case of a finite dead time 'dead', the distribution (for dt > dead) is +// still exponential with the same slope 'lambda'. 'lambda' should be determined +// in a region of 'dt' which is not affected by the dead time, i.e. at not too +// low 'dt'. +// +// +// +// II. Problems in the presence of calibration events +// -------------------------------------------------- +// If calibration events are taken interlaced with cosmics, and if the dead time +// is negligible, the distribution of time differences 'dt' between cosmics can +// be used for calculating the effective observation time, as if the calibration +// events were not present. +// +// In the case of a non-negligible dead time 'dead', however, the distribution of +// time differences between cosmics is distorted, because a cosmics event may be +// lost due to the dead time after a calibration event. Even if the time +// intervals are ignored which contain a calibration event, +// +// +// ---|---------o--------|---------> t +// +// cosmics calib cosmics +// +// <----------------> <==== time interval to be ignored +// +// +// the distribution of 'dt' is still distorted, because there would be no +// 'dt' with dt > tau_calib = 1/lambda_calib. The distribution would also be +// distorted in the region dt < tau_calib, due to calibration events occuring +// shortly after cosmics events. As a result, the slope of the distribution of +// 'dt' would not reflect the ideal cosmics event rate (see second figure; the +// values assumed in the simulation are lambda = 200 Hz, lambda_calib = 50 +// Hz, dead = 0.001 sec, total time = 500 sec, number of generated cosmics +// events = 100 000). +// +// +// Note also that some calibration events will not be recorded due to the dead +// time after a cosmics event. +// +// +// III. Proposed procedures +// ------------------------ +// +// A) The ideal event rate 'lambda' may be calculated from the distribution of +// the time difference 'dt_first' between a calibration event and the first +// recorded cosmics event after the calibration event. In the region +// +// dead < dt_first < tau_calib +// +// the probability distribution of dt_first is given by +// +// p(dt_first) = c * exp(-lambda*dt_first) +// +// where c is a normalization constant. 'lambda' can be obtained by a simple +// exponential fit to the experimental distribution of dt_first (see third +// figure). The fit range should start well above the average value of the dead +// time 'dead'. +// +// +// B) One may consider those time intervals between recorded cosmics events, which +// are completely contained in the region +// +// t_calib < t < t_calib + tau_calib +// +// where t_calib is the time of a recorded calibration event. +// +// +// <--------------- tau_calib -----------> +// +// +// 0 1 2 3 4 5 6 7 8 9 10 +// --|-o---|-|---|--|-|----|--|---|---|-|----o-|---|-|---------> t +// ^ ^ +// | | +// t_calib t_calib + tau_calib +// +// +// In this example, of the time intervals 0 to 10 only the intervals 1 to 9 +// should be retained and plotted. The distribution of the length 'dt' of these +// intervals in the region +// +// dead < dt < tau_calib +// +// is given by +// +// p(dt) = c * (tau_calib-dt-dead) * exp(-lambda*dt) +// +// A fit of this expression to the experimental distribution of 'dt' yields +// 'lambda' (see fourth figure). For 'dead' an average value of the dead time +// should be chosen, and the fit range should end well before dt = tau_calib-dead. +// +// +// Method A has the advantage that the p(dt_first) does not depend on 'dead'. +// 'dead' has to be considered when defining the fit range, both in method A and +// in method B. In method B the event statistics is larger leading to a smaller +// fitted error of 'lambda' than method A (see the figures). +// +// +// The effective observation time is again obtained by +// +// T_eff = N_cosmics / lambda +// +// where N_cosmics is the total number of recorded cosmics events. Note that +// N_cosmics is equal to +// +// N_cosmics = N_tot - N_calib +// +// where N_tot is the total number of recorded events (including the calibration +// events) and N_calib is the number of recorded calibration events. +// +// Note that if time intervals are discarded for the determination of lambda, +// the corresponding cosmics events need not and should not be discarded. +// +// +// IV. Procedure if the calibration events are taken in bunches +// ------------------------------------------------------------ +// In November 2004 the rate of calibration events is not constant. The events +// are taken in 200 Hz bunches every second, such that the rate is 200 Hz for +// 0.25 sec, followed by a gap of 0.75 sec. Then follows the next 200 Hz bunch. +// +// In this case it is proposed to consider for the calculation of 'lambda' only +// the cosmics events within the gaps of 0.75 sec. For these cosmics events one +// of the methods described in III. can be applied. +// +// +// V. Alternative pocedure +// ----------------------- +// The effective observation time can also be determined from the total +// observation time and the total dead time. The latter is written out by the DAQ. +// In this case it has to be made sure that the dead time is available in Mars +// when the effective observation time is calculated. +// ////////////////////////////////////////////////////////////////////////////// #include "MHEffectiveOnTime.h" @@ -646,6 +825,4 @@ void MHEffectiveOnTime::Paint(Option_t *opt) { - *fLog << all << "Paint: '" << opt << "'" << endl; - TH1D *h=0; TPaveStats *st=0; Index: trunk/MagicSoft/Mars/mhflux/MHThetaSq.cc =================================================================== --- trunk/MagicSoft/Mars/mhflux/MHThetaSq.cc (revision 7066) +++ trunk/MagicSoft/Mars/mhflux/MHThetaSq.cc (revision 7091) @@ -69,10 +69,10 @@ fHist.SetName("Theta"); fHist.SetTitle("Theta"); - fHist.SetZTitle("\\theta^{2} [deg^{2}]"); + fHist.SetZTitle("\\vartheta^{2} [deg^{2}]"); fHist.SetDirectory(NULL); // Main histogram fHistTime.SetName("Theta"); - fHistTime.SetXTitle("\\theta^{2} [deg^{2}]"); + fHistTime.SetXTitle("\\vartheta^{2} [deg^{2}]"); fHistTime.SetDirectory(NULL);