Dead time correction calculator for muon detector data. More...

#include <PNeXus.h>

Inheritance diagram for nxH4::PNeXusDeadTime:

Collaboration diagram for nxH4::PNeXusDeadTime:

Public Member Functions
	PNeXusDeadTime (const PNeXus *nxs, bool debug=false)
	Constructor - initializes dead time calculator from NeXus data.

bool	IsValid ()
	Check if the dead time calculator was initialized successfully.

double	Up () const
	Get the error definition for the minimizer (FCNBase requirement)

double	operator() (const std::vector< double > &par) const
	Function call operator - calculates chi-square for given parameters.

void	Minimize (const int i)
	Minimize dead time for a specific detector spectrum.

const std::vector< uint32_t > &	GetDimensions () const
	Get the dimensions of the count dataset.

Private Attributes
bool	fDebug {false}
	Debug flag - if true, print additional diagnostic information.

bool	fValid
	Validity flag - true if required data was loaded successfully.

int	fGoodFrames {-1}
	Number of good time frames for analysis.

float	fTimeResolution {0.0}
	Time resolution in picoseconds.

std::vector< uint32_t >	fDims = {0, 0, 0}
	Dimensions of count data [periods, spectra, bins].

int	fT0Bin {-1}
	T0 bin number (time zero reference)

int	fFgbBin {-1}
	First good bin for analysis.

int	fLgbBin {-1}
	Last good bin for analysis.

std::vector< float >	fDeadTime
	Dead time values per detector (microseconds)

std::vector< int >	fCounts
	Count data for minimization.

double	fUp {0.5}
	UP parameter for Minuit2 (0.5 for chi-square)

unsigned int	fIdx {0}
	Current spectrum index being minimized.

Detailed Description

Dead time correction calculator for muon detector data.

The PNeXusDeadTime class calculates dead time corrections for muon detector count data using ROOT Minuit2 minimization. It inherits from ROOT::Minuit2::FCNBase to implement a chi-square minimization function.

Dead time is the period after detecting an event during which the detector cannot register another event. This class estimates the dead time parameter for each detector spectrum by minimizing the deviation from expected count rates.

Typical Usage:

nxH4::PNeXus nexus("file.nxs");
nxH4::PNeXusDeadTime ndt(&nexus, false);  // false = no debug output
 
if (ndt.IsValid()) {
    auto dims = ndt.GetDimensions();
    // Minimize for each spectrum
    for (unsigned int i = 0; i < dims[1]; i++) {
        ndt.minimize(i);
    }
}

Note: Requires a valid PNeXus object with count data; Uses ROOT Minuit2 for minimization

See also: ROOT::Minuit2::FCNBase; nxH4::PNeXus

Definition at line 253 of file PNeXus.h.

Constructor & Destructor Documentation

◆ PNeXusDeadTime()

nxH4::PNeXusDeadTime::PNeXusDeadTime	(	const PNeXus *	nxs,
		bool	debug = false )

Constructor - initializes dead time calculator from NeXus data.

Reads count data, time resolution, and bin information from the NeXus file to set up the dead time calculation.
Parameters

nxs Pointer to PNeXus object containing the detector data

debug If true, print additional debug information during calculations
Note
After construction, check IsValid() to ensure data was loaded successfully

Examples: /workspace/LMU/musrfit/src/external/nexus/PNeXus.cpp, and /workspace/LMU/musrfit/src/external/nexus/PNeXus.h.

Definition at line 163 of file PNeXus.cpp.

References fCounts, fDebug, fDims, fFgbBin, fGoodFrames, fLgbBin, fT0Bin, fTimeResolution, and fValid.

Member Function Documentation

◆ GetDimensions()

const std::vector< uint32_t > & nxH4::PNeXusDeadTime::GetDimensions ( ) const

inline

Get the dimensions of the count dataset.

Returns the dimensions [periods, spectra, bins] of the count data being used for dead time calculation.
Returns
Vector of dimension sizes (typically 3D: [periods, spectra, bins])

Examples: /workspace/LMU/musrfit/src/external/nexus/PNeXus.h.

Definition at line 306 of file PNeXus.h.

References fDims.

◆ IsValid()

bool nxH4::PNeXusDeadTime::IsValid ( )

inline

Check if the dead time calculator was initialized successfully.

Returns
true if required datasets were found and loaded, false otherwise

Examples: /workspace/LMU/musrfit/src/external/nexus/PNeXus.h.

Definition at line 270 of file PNeXus.h.

References fValid.

◆ Minimize()

void nxH4::PNeXusDeadTime::Minimize ( const int i )

Minimize dead time for a specific detector spectrum.

Performs Minuit2 minimization to find the optimal dead time parameter for the specified spectrum index. Results are printed to stdout.
Parameters

i Spectrum index to minimize (0-based index into second dimension)
Note
Prints minimization results including dead time estimate and errors

The index i must be less than dims[1] (number of spectra)

Examples: /workspace/LMU/musrfit/src/external/nexus/PNeXus.cpp, and /workspace/LMU/musrfit/src/external/nexus/PNeXus.h.

Definition at line 300 of file PNeXus.cpp.

References fDims, and fIdx.

◆ operator()()

double nxH4::PNeXusDeadTime::operator() ( const std::vector< double > & par ) const

Function call operator - calculates chi-square for given parameters.

This is the objective function that ROOT::Minuit2 minimizes. It calculates the chi-square deviation between observed counts and expected counts corrected for dead time.
Parameters

par Vector of parameters (dead time values in microseconds)

Returns
Chi-square value for the given parameters

Examples: /workspace/LMU/musrfit/src/external/nexus/PNeXus.cpp, and /workspace/LMU/musrfit/src/external/nexus/PNeXus.h.

Definition at line 268 of file PNeXus.cpp.

References fCounts, fDims, fFgbBin, fGoodFrames, fIdx, fLgbBin, and fTimeResolution.

◆ Up()

double nxH4::PNeXusDeadTime::Up ( ) const

inline

Get the error definition for the minimizer (FCNBase requirement)

Returns the UP parameter which defines how the minimizer estimates errors. For chi-square minimization, UP = 0.5 corresponds to 1-sigma errors.
Returns
Error definition parameter (0.5 for chi-square)

Examples: /workspace/LMU/musrfit/src/external/nexus/PNeXus.h.

Definition at line 278 of file PNeXus.h.

References fUp.

Member Data Documentation

◆ fCounts

std::vector<int> nxH4::PNeXusDeadTime::fCounts

private

Count data for minimization.

Definition at line 318 of file PNeXus.h.

Referenced by operator()(), and PNeXusDeadTime().

◆ fDeadTime

std::vector<float> nxH4::PNeXusDeadTime::fDeadTime

private

Dead time values per detector (microseconds)

Definition at line 317 of file PNeXus.h.

◆ fDebug

bool nxH4::PNeXusDeadTime::fDebug {false}

private

Debug flag - if true, print additional diagnostic information.

Definition at line 309 of file PNeXus.h.

Referenced by PNeXusDeadTime().

◆ fDims

std::vector<uint32_t> nxH4::PNeXusDeadTime::fDims = {0, 0, 0}

private

Dimensions of count data [periods, spectra, bins].

Definition at line 313 of file PNeXus.h.

Referenced by GetDimensions(), Minimize(), operator()(), and PNeXusDeadTime().

◆ fFgbBin

int nxH4::PNeXusDeadTime::fFgbBin {-1}

private

First good bin for analysis.

Definition at line 315 of file PNeXus.h.

Referenced by operator()(), and PNeXusDeadTime().

◆ fGoodFrames

int nxH4::PNeXusDeadTime::fGoodFrames {-1}

private

Number of good time frames for analysis.

Definition at line 311 of file PNeXus.h.

Referenced by operator()(), and PNeXusDeadTime().

◆ fIdx

unsigned int nxH4::PNeXusDeadTime::fIdx {0}

private

Current spectrum index being minimized.

Definition at line 320 of file PNeXus.h.

Referenced by Minimize(), and operator()().

◆ fLgbBin

int nxH4::PNeXusDeadTime::fLgbBin {-1}

private

Last good bin for analysis.

Definition at line 316 of file PNeXus.h.

Referenced by operator()(), and PNeXusDeadTime().

◆ fT0Bin

int nxH4::PNeXusDeadTime::fT0Bin {-1}

private

T0 bin number (time zero reference)

Definition at line 314 of file PNeXus.h.

Referenced by PNeXusDeadTime().

◆ fTimeResolution

float nxH4::PNeXusDeadTime::fTimeResolution {0.0}

private

Time resolution in picoseconds.

Definition at line 312 of file PNeXus.h.

Referenced by operator()(), and PNeXusDeadTime().

◆ fUp

double nxH4::PNeXusDeadTime::fUp {0.5}

private

UP parameter for Minuit2 (0.5 for chi-square)

Definition at line 319 of file PNeXus.h.

Referenced by Up().

◆ fValid

bool nxH4::PNeXusDeadTime::fValid

private

Validity flag - true if required data was loaded successfully.

Examples: /workspace/LMU/musrfit/src/external/nexus/PNeXus.h.

Definition at line 310 of file PNeXus.h.

Referenced by IsValid(), and PNeXusDeadTime().

The documentation for this class was generated from the following files:

/workspace/LMU/musrfit/src/external/nexus/PNeXus.h
/workspace/LMU/musrfit/src/external/nexus/PNeXus.cpp

nxs	Pointer to PNeXus object containing the detector data
debug	If true, print additional debug information during calculations

Public Member Functions

Private Attributes

Detailed Description

Constructor & Destructor Documentation

◆ PNeXusDeadTime()

Member Function Documentation

◆ GetDimensions()

◆ IsValid()

◆ Minimize()

◆ operator()()

◆ Up()

Member Data Documentation

◆ fCounts

◆ fDeadTime

◆ fDebug

◆ fDims

◆ fFgbBin

◆ fGoodFrames

◆ fIdx

◆ fLgbBin

◆ fT0Bin

◆ fTimeResolution

◆ fUp

◆ fValid