Peak Scan Panel

Introduction

The Peak Scan panel allows the user to find the position of a device which maximizes intensity.

Basic description of functionality

The Peak Scan panel allows a user to scan a device through a range of values. The panel will plot the intensity at each point. It will also fit a Gaussian curve to the data and display the value and position of the curve peak.

Picture of the Peak Scan Panel

Components of the Peak Scan Panel

  1. Peak Scan

    Peak Scan Subpanel
    • Device

      The user is required to choose a device for which peak scan is performed.

    • Range

      The user specifies the interval of device values, centered at the current device position.

    • Step Size

      The user enters step size. The number of points for the scan is calculated as device range divided by the step size.

    • Duration

      This field specifies the value till which counting is performed at every point of the peak scan.

    • Count Against

      The user selects between Time and Monitor as the device for which Duration counts are measured.

    • Data to Display

      The user selects Detector or Monitor as data to be displayed when peak scan is executed.

    • Accept Fit Result

      If this option is selected, after the peak in the given device range is found, the device will be automatically moved to the position at which this peak was reached.

    • Find Peak

      Clicking this button will start a scanning process. Counts vs Position plot will be updated in real time as the scan is progressing.

  2. Fit Parameters

    Fit subpanel of the Peak Scan Panel
    • Background, Position, Height, Width

      After scan is finished, the Gaussian curve will be fitted to the count data in order to determine device position (Position) at which maximum count is reached. Background, Height and Width are calculated characteristics of the fitted Gaussian curve.

  3. Move to Fit

    Move subpanel of the Peak Scan Panel
    • Move to Fit

      Clicking Move to Fit button will instruct the server to move the device to the center of the fit.

    • Redefine

      Clicking Redefine button will drive a device to the target value given in the associated text field.

  4. New Lattice Values

    This subpanels refers to the special case when A4 has been chosen as a device in peak scan, and when Ei and Ef are assumed to be equal. In this case, A4 peak position can be used to calculate d-spacing of the sample.

    Lattice subpanel of the Peak Scan Panel
    • Uncorrected Fit Result

      Uncorrected fit field displays the value of the d-spacing determined by the peak scan. The user types in a number for the conversion field. This number is multiplied by uncorrected fit value and is displayed in New Value field.

    • Redefine Lattice Parameters

      User checks a combination of a, b, c boxes. Upon clicking the redefine lattice parameters button, the command to redefine checked parameters of the sample lattice to the New Value is sent to the server. Server redefines the lattice parameters and sends a client a confirmation notice