LiF data pack supporting "Observation of diffraction contrast in scanning helium microscopy"

All the experimental data from the paper is included in this data pack including both the images and the z scans. Images from the paper are presented in three different formats with filenames scan00*****: 1) .png file which is an unprocessed image of the raw data. <br> 2) .gwy file which is an unprocessed version of the data that can be opened in Gwyddion<br> 3) .mat file which contains all the measured data that can be opened in MATLAB The .mat file contains the most information and requires some explanation to easily understand.<br> The data is saved in a structure named meas, the key fields are as follows: meas.target - A matrix of the target position for each pixel, with a column for each of the x,y coordinates<br> meas.inputs - Input parameters used in the scanning program to collect the data<br> meas.initial_pos - Position of each the three stages at the start of the scan. The 3rd coordinate is the z scan and does not change throughout the scan<br> meas.data - A vector of the measured current at each pixel in Amps<br> meas.image - A matrix that represents the acquired image The remaining fields are explained at the bottom of the readme. The z scans are saved Z*****.mat and can be opened in MATALB.<br> The key variables in the data files are: z_position - Raw z coordinate of the positioner in nm<br> current_z - Measured current at each point in Amps<br> m - Horizontal scan gradient (approximately 1)<br> m2 - Vertical scan gradient (approximately 0)<br> step_pos - x coordiate at z_position=0<br> step_pos_v - y coordinate at z_position=0 The x,y position at each point in the scan can then be obtained from<br> x=step_pos + m*(z_position)<br> y=step_pos_v + m2*(z_position) <br> The true z distance between the pinhole and the sample in nm can be calculated from z=z_position-4295000 The included data in the pack contains: Images presented in the paper:<br> scan001357<br> scan001361<br> scan001398<br> scan001415 Z000006.mat - z scan of flat region<br> Z000008.mat - z scan of heavily distorted region<br> Z0000012.mat - z scan of lightly distorted region<br> Z000013.mat - z scan of HOPG z_scan_movie.avi - Video illustrating how the images vary with z<br> scan001401-scan001413 - Data to produce the video In addition, the analysis scripts have been included for reference. <br> The scripts can be used to regnerate the figures in the paper. <br> The remaining fields in the meas structure are:<br> meas.date_time - Start date and time of the scan<br> meas.type - Scan pattern of the image. Always raster_jump<br> meas.p1 - Unused pressure<br> meas.p2 - Unused pressure<br> meas.p3 - Unused pressure<br> meas.p_srce - Source pressure at the start of the scan<br> meas.p_diff - Differential stage pressure at the start of the scan<br> meas.p_smpl - Sample pressure at the start of the scan<br> meas.p_det - Detector pressure at the start of the scan<br> meas.N_dwell - Number of current measurements taken at each pixel<br> meas.comments - comments (unused)<br> meas.det_params - Detector parameters used in the scan<br> meas.labtemp - A vector of the labtemp at each pixel (unused)<br> meas.return_state - Error status <br>