# Asymmetries

## Asymmetries Calculations

Here is the list of functions used to calculate asymmetries that are provided by the "Neutron Scattering" XOP:

#### Asymmetry(Rpp, Rbp, Rpm, Rbm)

The Asymmetry function returns the asymmetry from the count rates Rpp, Rbp, Rpm and Rbm. Rpp and Rbp are the peak and background count rates for the [+] polarisation state. Rpm and Rbm are the peak and background count rates for the [-] polarisation state. The asymmetry is defined by:

#### AsymmetrySDev(Rpp, Rbp, Rpm, Rbm, RppSDev, RbpSDev, RpmSDev, RbmSDev)

The AsymmetrySDev function returns the asymmetry standard deviation from the count rates Rpp, Rbp, Rpm, Rbm and the corresponding standard deviations. Rpp and Rbp are the peak and background count rates for the [+] polarisation state. Rpm and Rbm are the peak and background count rates for the [-] polarisation state. The asymmetry standard deviation is defined by:

#### AsymmetryOpt(Npp, Nbp, Npm, Nbm, Tpp, Tbp, Tpm, Tbm, Mp, Mb)

The AsymmetryOpt function returns the asymmetry from the counts Npp, Nbp, Npm, Nbm, the counting times Tpp, Tbp, Tpm, Tbm and the monitor values Mp and Mb in the case of cyclic measurements. The first indices [p] or [b] stand for peak or background measurements. The second indices stand for the [+] and [-] polarisation states. The asymmetry is defined by:

#### AsymmetryOptSDev(Npp, Nbp, Npm, Nbm, Tpp, Tbp, Tpm, Tbm, Mp, Mb)

The AsymmetryOptSDev function returns the asymmetry standard deviation from the counts Npp, Nbp, Npm, Nbm, the counting times Tpp, Tbp, Tpm, Tbm and the monitor values Mp and Mb in the case of cyclic measurements. The first indices [p] or [b] stand for peak or background measurements. The second indices stand for the [+] and [-] polarisation states. The asymmetry standard deviation is defined by:

#### AsymmetryOptDDT(Npp, Nbp, Npm, Nbm, Tpp, Tbp, Tpm, Tbm, Mp, Mb, a, b)

The AsymmetryOptDDT function returns the asymmetry from the counts Npp, Nbp, Npm, Nbm, the counting times Tpp, Tbp, Tpm, Tbm and the monitor values Mp and Mb in the case of cyclic measurements. This function corrects the counts for detector dead-time using a and b, the first and second order correction coefficients expressed in seconds. The first indices [p] or [b] stand for peak or background measurements. The second indices stand for the [+] and [-] polarisation states. The asymmetry is defined by:

#### AsymmetryOptDDTSDev(Npp, Nbp, Npm, Nbm, Tpp, Tbp, Tpm, Tbm, Mp, Mb, a, b , aSDev, bSDev)

The AsymmetryOptDDTSDev function returns the asymmetry standard deviation from the counts Npp, Nbp, Npm, Nbm, the counting times Tpp, Tbp, Tpm, Tbm and the monitor values Mp and Mb in the case of cyclic measurements. This function corrects the counts for detector dead-time using a and b, the first and second order correction coefficients expressed in seconds, and aSDev, bSDev the corresponding standard deviations. The first indices [p] or [b] stand for peak or background measurements. The second indices stand for the [+] and [-] polarisation states. The asymmetry standard deviation is defined by: