GainVoltPmtParameters Class Reference

#include <GainVoltPmtParameters.h>

Public Member Functions
	GainVoltPmtParameters (double refVoltage, double gains[5])
	GainVoltPmtParameters (int n, double volts[], double gains[])
	GainVoltPmtParameters (const GainVoltPmtParameters &parameters)
GainVoltPmtParameters &	operator= (const GainVoltPmtParameters &parameters)
void	set (double refVolt, double gains[5])
	Set the voltages and gains. More...
void	set (int n, double volts[], double gains[])
	Set the voltages and gains. More...
void	fit ()
	fit the data
double	getMultConstant () const
	Get multiplicative constant.
double	getExponent () const
	Get exponent of the power law.
double	getGain (double voltage) const
	Get the gain obtained if the given voltage is applied.
double	getVoltage (double gain) const
	Get the voltage need to obtain the given relative gain.
int	getNPoints () const
	Get the number of data points available and used for this PMT.
void	print ()
	Print the information of this PMT.
PmtIdentifier &	getPmtIdentifier ()
	Get the PMT identifier.
bool	isValid () const
	Determine whether the input data are valid. More...

Static Public Member Functions
static void	setDefaults (double multCoefficient, double exponent)

Static Public Attributes
static int	ioMode =2

Protected Attributes
PmtIdentifier	_id
double	_a
	multiplicative coefficient
double	_b
	Exponent.
map< double, double >	_data
	HV/Gain data.
PowerLawFit< double >	_fit
	Transient Fit Object.

Static Protected Attributes
static double	_defaultA = 2.56e-29
static double	_defaultB = 10.71

Friends
ostream &	operator<< (ostream &os, GainVoltPmtParameters &object)
	Write obbject to ostream.
istream &	operator>> (istream &is, GainVoltPmtParameters &object)
	Read object from istream.

Detailed Description

Class used to describe the gain vs bias voltage of a photomultiplier tube. Input parameters consist of experimentally measured relative gain vs bias voltage. Output parameters consist of the gain parameters obtained with a power law parameterization.

Definition at line 13 of file GainVoltPmtParameters.h.

Member Function Documentation

bool GainVoltPmtParameters::isValid

(

)

const

Determine whether the input data are valid.

Determine whether the input data are sufficient and valid to perform a fit to determine the gain coefficients.

Definition at line 69 of file GainVoltPmtParameters.cxx.

References _data.

Referenced by fit().

void GainVoltPmtParameters::set	(	double	refVolt,
		double	gains[5]
	)

Set the voltages and gains.

Set the voltages and gains

Parameters

refVolt	reference voltage
gains	array of five gain values obtained with voltages ref-100,ref-50,ref,ref+50,ref+100

Definition at line 42 of file GainVoltPmtParameters.cxx.

References _data.

void GainVoltPmtParameters::set	(	int	n,
		double	volts[],
		double	gains[]
	)

Set the voltages and gains.

Set the voltages and gains

Parameters

n	number of data points
volts[]	voltage settings
gains[]	relative gains obtained with the given voltage setttings

Definition at line 57 of file GainVoltPmtParameters.cxx.

References _data.

void GainVoltPmtParameters::setDefaults ( double  multCoefficient, double  exponent  )

static

Set the default coefficients used in lieu of the fitted coefficients when there are insufficient or invalid data to perform a fit.

Definition at line 220 of file GainVoltPmtParameters.cxx.

References _defaultA.

Member Data Documentation

double GainVoltPmtParameters::_defaultA = 2.56e-29

staticprotected

Default value for PMTs that have incomplete data and for which a fit cannot be done. The multiplicative coefficient "_defaultA" is obtained a geometric average of the multiplicative coefficients of many towers. The exponent "_defaultB" is obtained as arithmetic average of the exponents of other towers. These values are NOT calculated internally and must be externally by the user of this code using the setDefaults() public method.

The following values were obtained from an average of 2000 STAR EMC PMTs. To change these values, use the "void setDefaults(double, double)" method.

Definition at line 78 of file GainVoltPmtParameters.h.

Referenced by fit(), and setDefaults().

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

• StEmcUtil/voltageCalib/GainVoltPmtParameters.h
• StEmcUtil/voltageCalib/GainVoltPmtParameters.cxx