skbeam.core.calibration.estimate_d_blind

skbeam.core.calibration.estimate_d_blind(name, wavelength, bin_centers, ring_average, window_size, max_peak_count, thresh)

Estimate the sample-detector distance

Given a radially integrated calibration image return an estimate for the sample-detector distance. This function does not require a rough estimate of what d should be.

For the peaks found the detector-sample distance is estimated via

\[D = \frac{r}{\tan 2\theta}\]

where \(r\) is the distance in mm from the calibrated center to the ring on the detector and \(D\) is the distance from the sample to the detector.

Parameters

namestr

The name of the calibration standard. Used to look up the expected peak location

Valid options: [‘Al2O3’, ‘CeO2’, ‘LaB6’, ‘Ni’, ‘Si’]

wavelengthfloat

The wavelength of scattered x-ray in nm

bin_centersarray

The distance from the calibrated center to the center of the ring’s annulus in mm

ring_averagearray

The average intensity in the given ring of a azimuthally integrated powder pattern. In counts [arb]

window_sizeint

The number of elements on either side of a local maximum to use for locating and refining peaks. Candidates are identified as a relative maximum in a window sized (2*window_size + 1) and the same window is used for fitting the peaks to refine the location.

max_peak_countint

Use at most this many peaks

threshfloat

Fraction of maximum peak height

Returns

dist_samplefloat

The detector-sample distance in mm. This is the mean of the estimate from all of the peaks used.

std_dist_samplefloat

The standard deviation of d computed from the peaks used.