Vector Scan Panel

Introduction

The Vector Scan allows a user to scan h, k, l and energy transfer devices.

Basic description of functionality

The Vector Scan panel contains h, k, l, and energy transfer devices to be driven as a part of the scan. For each device the user can set the initial position, step size, center and final destination parameters.

Picture of the Vector Scan panel

Components of the Vector Scan Panel

  1. Instrument

    Instrument subpanel of the Vector Scan panel
    • Fixed Energy

      This field allows the user to fix either incident (Ei) or final (Ef) energy. The user is required to type the fixed energy value in meV. The energy value has to be positive. By default final energy Ef is fixed.

    • Mode

      The user may choose between Initial/Final, Initial/Step or Center/Step modes of devices. The default mode is Initial/Final.

      • Given values for the Initial and Final positions, value of the Center position is set at the half distance between Initial and Final. Step is calculated as the difference between Final and Initial positions divided by the number of scan points.

      • Given values for the Initial position and Step, the value for the Final position is set to the Initial position plus Step multiplied by the number of points. The Center is set to the Initial position plus half of Step multiplied by the number of points.

      • Given values for the Center position and Step, the Initial position is set to the Center minus half of the Step multiplied by the number of points. Final position is set to the Center plus half of the Step multiplied by the number of points.

    • h, k, l, and Energy transfer (Et)

      Device ranges for devices h, k, l, and Et have to be specified with two values chosen by the scan mode. Based on these entered values and a value for the number of points, the other two values for the associated device are calculated and displayed automatically.

  2. Scan Parameters

    Scan parameters subpanel of the Vector Scan panel
    • Number of points

      This field specifies the number of points in the vector scan. The entered value has to be a positive integer.

    • Base Count

      This field defines the base count parameter of the vector scan. At each point of the scan, the system will count for Base Count multiplied by Prefactor. The entered value has to be a positive integer. The default values is 1.

    • Prefactor

      This field defines the prefactor parameter of the vector scan. At each point of the scan, the system will count for Base Count multiplied by Prefactor. The entered value has to be a positive integer. The default value of Prefactor is 1.

    • Data of Interest

      The user selects Detector or Monitor as data of interest to be recorded when run scan is performed.

    • Count Against

      The user can choose between Monitor or Time as the device for which Base Count multiplied by Prefactor counts are measured.

  3. Environment

    Environment subpanel of the Vector Scan panel
    • Controller type

      All environment control devices installed on the server will be listed in the drop down menu. The user may choose a controller to be set during scan. Depending on the selected type of the environment controller, different set of input fields will be added to the environment subpanel. (Optional)

    • Temperature Controller

      This device has the following parameters that the user is required to enter.

      • Set Point

        Specifies the temperature value which will be set before the scan begins.

      • Tolerance

        Specifies the acceptable tolerance interval around the Set Point for temperature controller.

      • Tolerance Band Time

        Specifies how long (in minutes) the temperature must be continuously within tolerance of the Set Point, before the temperature is considered to have reached the Set Point.

      • Max Wait Time

        Specifies the maximum time (in minutes) that the system will attempt to reach the Set Point. If it does not reach the Set Point within this timeout, the system will issue a warning message to the user and proceed with a scan. For example, if Max Wait Time set to 0, the system will give up attempting to reach the Set Point immediately and proceed with the scan.

      • Initial Hold Time

        Specifies the delay (in minutes) between reaching the Set Point and beginning of the scan. If Max Wait Time has elapsed, the system will still hold for the specified number of minutes before proceeding with the scan. This time should to be sufficient for the whole sample to reach equilibrium.

    • Magnet Controller

      • Set Point

        Specifies the magnet value which will be set before the scan begins.

      • Tolerance

        Specifies the acceptable tolerance interval around the Set Point for magnet controller.

      • Initial Hold Time

        Specifies the delay (in minutes) between reaching the Set Point and beginning of the scan. This time should to be sufficient for the whole sample to reach equilibrium.

  4. Scan Description

    Scan description subpanel of the Vector Scan panel
    • Scan name

      This field gives the name the scan.

    • Data file prefix

      In this field the user may enter data file prefix. This string will be added to the each data file name. (Optional)

    • Comments

      The user may add comments to the vector scan. (Optional)

  5. Controls

    • Clear

      Clicking this button sets all text fields to their default values. Drop down combo boxes are not changed.

    • Dry Run

      By clicking this button, the user sends a command to dry run the scan. The server calculates positions of devices for each point of the scan and sends the user a summary of device positions. After dry run is complete, the server deletes the scan description from memory.

    • Save

      By clicking Save, the user sends a command to the server to save the scan definition. The server saves the scan in the data storage.

    • Save and Run

      On this command, the server saves the entered scan and executes it. For each point in the scan, the server moves all scanning devices to the specified position and performs a count. After executing the scan, the server sends the user a summary of device positions and counts. Refer to Scan description for further details.