CN107844487A - For composing the automatic data acquisition method of analysis photoelectron/low energy electron microscopy - Google Patents

Abstract

The invention relates to an automatic data acquisition method for spectrum analysis photoelectron/low-energy electron microscope, comprising the following steps: setting scanning parameters, CCD camera parameters, establishing folders and files under the selected data storage path; automatically controlling the electron microscope and The CCD collects images and records the related equipment and experimental parameters at the same time. According to the unified storage and naming rules, the present invention stores the experimental data and related parameters in an orderly manner, the file structure is reasonable, easy to identify and manage, and it is convenient for data analysis, review and equipment adjustment.

Description

Automated Data Acquisition Method for Spectral Analysis Photoelectron/Low Energy Electron Microscopy

technical field

The invention relates to an automatic control data acquisition method for spectrum analysis photoelectron/low energy electron microscope (SPELEEM, Elmitec company), which belongs to computer automatic control technology.

Background technique

Spectrum Analysis Photoelectron/Low Energy Electron Microscope (SPELEEM) is a powerful surface and nanoscience research equipment, which collects photoelectrons excited from the surface or electrons reflected from the surface by the electron gun for imaging, equipped with an energy analyzer It also has the capability of energy spectrum analysis. With its functions in real-time imaging, diffraction, photoelectron spectroscopy, element resolution, and micro-area analysis, SPELEEM can obtain comprehensive information on morphology, structure, chemical composition, and electronic structure. Our SPELEEM is the most widely used product of German Elmitec company in this field. The realization method of SPELEEM common functions (such as LEED-IV, LEEM-IV, XPS, etc.) is generally to collect a picture series through continuous scanning parameters, and then use image processing software to extract the intensity curve or energy band structure from the picture series. SPELEEM control software comes with simple data acquisition programs for users to use, but these programs have the following shortcomings: the naming method of data storage cannot reflect the relevant information of the experiment, and the file structure is not clear enough, making the batch collected data difficult to identify and inconvenient to manage ; During continuous scanning, only the image column itself is stored, but the parameters of the microscope and CCD camera, as well as the parameter changes during the scanning process are not stored, and can only rely on handwriting to record several main parameters, which is inefficient and inevitable. This is not conducive to subsequent data review and analysis, and it is not convenient to compare parameters for equipment adjustment.

Contents of the invention

For above-mentioned technical deficiency, the object of the present invention provides a kind of automatic data acquisition method that is used for spectral analysis photoelectron/low energy electron microscope, the present invention utilizes the built-in VBScript interface of SPELEEM control software to write data acquisition automatic control program, realizes SPELEEM better Commonly used functions significantly improve data collection efficiency and facilitate data management and subsequent analysis.

The technical solution adopted by the present invention to solve the technical problems is: an automatic data acquisition method for spectrum analysis photoelectron/low-energy electron microscope, comprising the following steps:

Set scanning parameters, CCD camera parameters, and create folders and files under the selected data storage path;

The electron microscope collects images through the CCD, and writes the collected images and corresponding parameters into the file at the same time.

The scan parameters include the start and end values of STV and the step size, and the CCD camera parameters include exposure time and accumulation times.

Described electron microscope collection image comprises the following steps: obtain the objective lens value Obj=coef0+coef1*STV ^coef2 that matches with it according to the STV value of electron microscope; coef0 is the Obj value before scanning begins, and coef1 and coef2 are equipment parameters; STV value and the objective lens value Obj are output to the electron microscope, and the electron microscope uses this STV value and the objective lens value Obj to collect an image.

The scan parameters include the start and end values of the objective lens Obj and the step size, and the CCD camera parameters include exposure time and accumulation times.

The image collection by the electron microscope includes the following steps: outputting the objective lens value Obj to the electron microscope, and the electron microscope collects an image according to the objective lens value Obj.

The scanning parameters include the time interval for collecting images; the parameters of the CCD camera include exposure time and accumulation times.

The electron microscope collects images through the CCD specifically collects images according to time intervals.

The described establishment of folders and files includes the following steps:

Each scan creates a new folder in the selected data storage path, and the naming format of the folder is: Year_Month_Day_N_Funct; where Year, Month, and Day represent the year, month, and day of the experiment day read from the computer system; N represents It is the Nth folder created under the storage path of the day, indicating the experimental link of this scan; Funct indicates the function to be realized by this scan;

The picture column obtained by each functional scan is stored in the folder established for this scan. The naming format of the pictures in the picture column is: Year_Month_Day_N_serial number; where Year, Month, and Day represent the day of the experiment read from the computer system The year, month, and day; N indicates the Nth folder created under the storage path of the day, indicating the experimental session where the scan is located; the serial number indicates the number of the picture in the picture column.

Described file comprises three txt files, and its naming is to change the Funct suffix of folder name into camera, microscope, trace respectively; Wherein camera file deposits CCD camera parameter; Microscope file saves 102 parameters of the microscope before scanning starts; trace file Parameter changes during the scan are recorded.

The trace file includes one or more of image serial number, acquisition time, STV value, objective lens value, and temperature, which can be directly read for spectrogram analysis.

The present invention has the following beneficial effects and advantages:

1. The programming is simple and easy, no additional software installation is required.

2. The data is automatically named and stored according to the scanning function, which is time-saving and efficient, and can reflect the relevant information of the experiment. The file structure is reasonable and easy to identify and manage.

3. It is stored together with important parameters and parameter changes, which is beneficial for review analysis and equipment adjustment.

4. Better realize the common functions of SPELEEM.

Description of drawings

Fig. 1 is a flow chart of the method of the present invention.

Detailed ways

The present invention will be further described in detail below in conjunction with the examples.

The invention automatically controls the SPELEEM equipment to collect experimental data by writing a VBscript script program, which is time-saving and efficient, and can facilitate data management, analysis and equipment adjustment, and can better realize the common functions of the equipment. The writing and debugging of the VBscript script program is carried out in the script editor provided by the SPELEEM control software, making full use of the methods and attributes provided by the device control software, and the FileSystemObject (FSO) object of the Windows system, without installing other software, which is simple and easy.

The whole system includes a set of Elmitec-SPELEEM equipment, a computer running Windows7 operating system and SPELEEM control software LEEM2000, U-view2002. Among them, LEEM2000 is the microscope control software, which is used to adjust the electron gun, lens and energy analyzer on the imaging optical path; U-View2002 is the image acquisition control software, which is used to adjust the image acquisition parameters of the CCD camera. The writing and debugging of the VBscript script program is carried out in the script editor provided by the SPELEEM control software. The automatic control of the microscope and CCD camera, as well as the reading and writing of related parameters, are realized by calling the methods and properties provided by the control software; VBscript can directly call the FileSystemObject (FSO) object of the Windows operating system to manage the naming and storage of data files.

The data to achieve a certain function needs to be collected through an automatically controlled scanning process, which we call a functional scan. The experiment is to complete the function scan again and again. Perform a functional scan, including the following steps:

According to the function to be realized, set the parameters to control the scanning process, generally the start and end values of the scanning range and step length; set the CCD imaging parameters according to the imaging state, generally the accumulation times and exposure time;

Automatically create a folder for this scan according to the storage and naming rules under the specified data storage path, and save the microscope parameters and CCD camera parameters in this folder as a txt file, and generate a txt file ready to be written into the scan track.

Scan, automatically collect and store image columns according to naming rules, and at the same time write parameter changes to a txt file that stores scan tracks.

The specified data storage path is the data storage path selected by the experimenter when the program is running.

The storage and naming rules include:

All functional scans done during the experiment of the day are saved to the designated storage path dedicated to the day.

Each function scan creates a new folder named as: Year_Month_Day_N_Funct. Among them, Year, Month, and Day represent the year, month, and day of the experiment day read from the computer system; N represents the Nth folder created under the storage path of the day, which can indicate which part of the experiment process this scan is in. link; the last Funct is the abbreviation suffix, indicating the function to be realized in this scan. For example, 2016_08_24_003_XPS means that the scan to realize the XPS function was done on August 24, 2016, which is the third scan done during the experiment on that day.

The picture column obtained by each function scan is stored in the folder automatically created for it. The name of the picture in the picture column is to change the Funct suffix of the folder name into a serial number, such as 2016_08_24_003_M, and M is stored in order from 000 Increase. In addition to the list of scanned pictures, the folder also contains three txt files named after changing the Funct suffix of the folder name to camera, microscope, and trace respectively. The camera file stores the main parameters of the CCD camera; the microscope file stores 102 parameters of the microscope before scanning; the trace file records the parameter changes during the scanning process.

According to the commonly used function of SPELEEM, the function scanning that the present invention relates to has (with the abbreviation suffix mark corresponding to Funct): XPS, LMIV, LDIV, FOCUS, MOV, PS.

The most typical one is the XPS scanning with the goal of obtaining the XPS energy spectrum, as shown in Figure 1, and the scanning process is described as follows:

Under the premise of satisfying the imaging resolution, choose a larger binning value to reduce the pixels of the picture, which can not only improve the signal strength, but also reduce the size of the picture and save storage space. Adjust the optical path of the microscope to make the image clear, and the equipment is in a state where XPS function scanning can start.

Run the program, follow the prompts to input the start and end values of the scanning parameters and the step length (assumed to be 335, 354.8, 0.2, unit V), and the CCD image acquisition parameters. The scanning parameter of XPS is the Start Voltage (STV, unit V) added to the sample, which characterizes the kinetic energy (unit eV) of the photoelectrons excited by X-rays. The start and end values determine the energy range of the scanned XPS spectrum, and the step size determines the fineness of the energy spectrum. The CCD image acquisition parameters that need to be set are exposure time and accumulation times. The choice of exposure time needs to comprehensively consider the MCP (micro channel plate) voltage and the intensity distribution of the XPS spectrum, so as to obtain sufficient signal intensity and prevent damage to the MCP and fluorescent screen due to excessive signal in individual areas. Larger accumulation times can obtain better image quality, but the time required will be longer.

Select the data storage path, all the data of the current day will be stored under this path. If this scan is not the first scan of the day, the storage path specified in the first scan will be used by default.

Automatically create a folder 2016_08_24_003_XPS for this XPS scan under the selected storage path (assuming this XPS scan is the third scan done on August 24, 2016). Read the 102 parameters on the optical path of the microscope one by one, write them into the 2016_08_24_003_microscope.txt file and save them; read the main parameters of the CCD camera, write them into the 2016_08_24_003_camera.txt file and save them; generate the 2016_08_24_003_trace.txt file, ready for scanning Write parameter changes during the process.

Start the scanning process. The picture acquisition steps are as follows: judge whether the STV value is within the set scanning range, and if so, calculate the matching objective lens value Obj (Objective, unit mA). Obj represents the focal length of the electromagnetic objective lens, which can be obtained by the following formula:

Obj＝coef0+coef1×STV ^coef2

Among them, coef0 is the Obj value before the scan starts, coef1 and coef2 are parameters related to the equipment, which can be obtained by sampling multiple sets of STV values and Obj values in a large range on samples that are easy to focus and perform fitting.

Transfer the (STV, Obj) value to the corresponding power supply, wait for a certain period of time to stabilize the power supply, start the CCD camera, collect images according to the set exposure time and accumulation times, store the obtained images as pictures in the specified format, and then save the pictures The sequence number, STV and Obj values are written to the trace file. Next, increase the STV value according to the set step length, repeat the above image collection process until the STV reaches the end value of the scan, and end the scan process. The final trace file is as follows:

The first column is the serial number of the scanned pictures, and the second and third columns are the (STV, Obj) values when each picture is collected. The parameters in the trace file can be directly read for drawing charts, and can also be compared with the imaging effect for device adjustment. For the format of the stored pictures, the 16-bit uncompressed TIFF format is suitable, which can preserve the intensity information of the image without loss.

After the final scan is completed, restore (STV, Obj) to the value before the start of the scan, exit the program, and complete the function scan.

Refer to the description of the XPS scanning process above, and the description of other function scanning is as follows:

LMIV stands for LEEM-IV, which records the change of LEEM image with STV, which represents the energy of the electron beam incident on the surface of the sample.

LDIV stands for LEED-IV and records the variation of the LEED pattern with STV, which represents the energy of the electron beam incident on the surface of the sample.

The scanning process of LMIV and LDIV is the same as that of XPS.

FOCUS is focus scanning, and its purpose is to find the best imaging focal length. By scanning the objective lens value Obj and storing the picture, finally find out the value of Obj corresponding to the clearest image. The difference between FOCUS and XPS scanning processes lies in the scanning parameters. The scanning parameter of FOCUS is Obj, and there is no need to change other parameters when changing Obj. In order to facilitate the viewing of parameters and adjustment of imaging, the content of the trace file scanned by FOCUS is the same as that scanned by XPS, although the STV has not been changed during FOCUS scanning.

MOV stands for movie, which is used to record the changes of images over time during the experiment. There is only one scanning parameter that MOV needs to set, that is, the time interval t between the two pictures before and after the acquisition. After the scanning process starts, a picture is collected every time t, and this process will continue until the program is terminated artificially. The basic content of the MOV trace file contains two columns of values. The first column is the serial number of the scanned pictures, and the second column is the collection time of each picture. The collection time of the first picture is set to 0. If there are other experimental parameters that are changing over time, such as the temperature of the sample, write them into the trace file.

PS stands for picture series, the purpose of which is to keep the experimental conditions and imaging parameters unchanged and record a series of pictures, and perform drift correction and cumulative averaging on the picture series, which can reduce the impact of imaging drift, improve the signal-to-noise ratio, and obtain better imaging resolution . The scanning parameter that PS needs to set is the number of pictures in the picture column, and the program will end when the set number of pictures is collected. Although the scanning process does not involve changes in microscope parameters, we still created a trace file with the same content as XPS scanning, so as to view parameters and adjust imaging.

Claims (10)

1. the automatic data acquisition method for composing analysis photoelectron/low energy electron microscopy, it is characterised in that including following step Suddenly：

Sweep parameter, CCD camera parameter are set, file and file are established under selected data storage path；

Electron microscope gathers image by CCD, while by the image of collection and corresponding parameter read-in to file.

2. the automatic data acquisition method according to claim 1 for being used to compose analysis photoelectron/low energy electron microscopy, its It is characterised by that the sweep parameter includes STV beginning, last value and step-length, CCD camera parameter includes time for exposure and cumulative time Number.

3. the automatic data acquisition method according to claim 1 for being used to compose analysis photoelectron/low energy electron microscopy, its It is characterised by that the electron microscope gathers image by CCD and comprised the following steps：

Matched object lens value Obj=coef0+coef1 × STV is worth to according to the STV of electron microscope^coef2；Coef0 is The Obj values before starting are scanned, coef1 and coef2 are device parameter；

STV values and object lens value Obj are exported to electron microscope, electron microscope and use this STV value and object lens value Obj collection figures Picture.

4. the automatic data acquisition method according to claim 1 for being used to compose analysis photoelectron/low energy electron microscopy, its Be characterised by beginning, last value and the step-length of the sweep parameter including object lens value Obj, CCD camera parameter include the time for exposure with Accumulative frequency.

5. the automatic data acquisition method according to claim 1 for being used to compose analysis photoelectron/low energy electron microscopy, its It is characterised by that the electron microscope gathers image by CCD and comprised the following steps：

Object lens value Obj is exported to electron microscope, electron microscope image is gathered according to object lens value Obj.

6. the automatic data acquisition method according to claim 1 for being used to compose analysis photoelectron/low energy electron microscopy, its It is characterised by that the sweep parameter includes the time interval of collection image；CCD camera parameter includes time for exposure and cumulative time Number.

7. the automatic data acquisition method according to claim 1 for being used to compose analysis photoelectron/low energy electron microscopy, its It is specially to gather image according to time interval to be characterised by that the electron microscope gathers image by CCD.

8. the automatic data acquisition method according to claim 1 for being used to compose analysis photoelectron/low energy electron microscopy, its It is characterised by described and establishes file and file comprises the following steps：

Scan all in selected data storage path that a newly-built file, the name form of file are each time：Year_ Month_Day_N_Funct；Wherein Year, Month, Day represent the year, month, day of the experimental day read from computer system； N represents it is the n-th file established under the store path on the day of, represents the experiment link where present scan；Funct tables Show and this time scan the function to be realized；

The picture row obtained by functionality scan are all stored in the file established for this scanning each time, picture in picture row Name form be：Year_Month_Day_N_ sequence numbers；Wherein Year, Month, Day represent the reality read from computer system Test the year, month, day on the same day；N represents it is the n-th file established under the store path on the day of, represents present scan place Experiment link；Sequence number represents it is at which figure in picture row.

9. the automatic data acquisition method according to claim 1 for being used to compose analysis photoelectron/low energy electron microscopy, its Be characterised by that the file includes three txt files, its name be by the Funct suffix of folder name be changed to respectively camera, microscope、trace；Wherein camera files storage CCD camera parameter；Before the preservation scanning of microscope files starts Microscopical 102 parameters；Parameters variation in trace file records scanning process.

10. the automatic data acquisition method according to claim 9 for being used to compose analysis photoelectron/low energy electron microscopy, It is characterized in that the trace files include the one or more in picture numbers, acquisition time, STV values, object lens value, temperature, It can directly read for spectrum analysis.