An electromagnetic energy meter light guide device single machine off-line automatic testing method and system

Abstract

The application discloses an electromagnetic energy meter light guide device single machine offline automatic testing method and system, and belongs to the technical field of particle physics detection. The method fixes the test piece containing a scintillator array and a light guide device on an electric slide rail, integrates control logic on a computer, directly drives the electric slide rail and a digitizer by calling a hardware driver library, and the computer is in a network disconnected state during the whole test. An integrated automatic scanning process is executed, the electric slide rail is controlled to drag the test piece to make two-dimensional motion according to a preset step and path, and the excitation source light spot is sequentially scanned on the end surface of the test piece; after the electric slide rail is stopped at a preset position, the computer immediately triggers the digitizer to collect the photodetector signal; after the full position data is obtained by repeated scanning, the signal response value is arranged according to the position to generate a performance distribution map and calculate the root mean square, which is used for evaluating the response uniformity of the light guide device. The application eliminates network dependence and communication delay, and improves the test efficiency and data reliability.

Description

Technical Field

[0001] This invention relates to the field of particle physics detection technology, specifically to a single-machine offline automatic testing method and system for electromagnetic calorimeter photoconductive devices. Background Technology

[0002] In particle physics experiments, the electromagnetic calorimeter (ECAL) is a core detector for measuring the energy and incident position of electrons and photons. An ECAL typically consists of an array of high-density absorbers and scintillators: incident particles develop into electromagnetic showers within the calorimeter, generating secondary charged particles that excite optical photons in the scintillators; these photons are collected, transmitted, and converted into electrical signals by a photodetector, from which energy and position information can be read out.

[0003] With the increasing event frequency of facilities such as the Large Hadron Collider (LHC), more stringent requirements are being placed on the energy resolution and response uniformity of electromagnetic calorimeters. To accommodate small-aperture, high-gain, radiation-resistant photomultiplier tubes (PMTs), optical guide structures are commonly used in engineering to guide, focus, and homogenize photons emitted from the scintillator array. The performance of the optical guide device directly determines the response uniformity of the edge scintillator, thus affecting the energy resolution constant of the entire calorimeter.

[0004] However, the performance evaluation of optical guide devices in the prior art has the following prominent problems:

[0005] 1. Low testing efficiency and insufficient automation: Existing laboratory testing often uses a dual-machine collaborative approach (one machine controls the electric slide rail, and the other controls the digitizer), achieving linkage through remote desktop and simulated mouse operation. This method is sensitive to the network environment; disconnection will lead to test interruption or data misalignment. Moreover, frequent software start-ups and shutdowns introduce a large amount of "dead time," requiring several hours to complete a prototype scan, which is difficult to meet the needs of batch optical waveguide R&D testing.

[0006] 2. Poor synchronization and low data reliability: The communication delay between the two machines is uncontrollable, and precise synchronization between motion stopping and signal acquisition cannot be achieved, which can easily cause mismatch between points and data, affecting the accuracy of response uniformity assessment.

[0007] 3. Lack of integrated offline testing solutions: Existing solutions rely on networks and remote desktops, and cannot run stably in a completely offline (disconnected from the network) environment, which limits the flexibility of laboratory deployment.

[0008] To address the aforementioned issues, there is an urgent need for a dedicated testing method and system for optical guide devices that can achieve offline single-machine operation, synchronous linkage of motion and acquisition, full-process automation, and high testing efficiency. Summary of the Invention

[0009] This invention aims to provide a single-machine offline automatic testing method and system for electromagnetic calorimeter photoconductor devices, in order to solve the technical problems of low testing efficiency, poor stability, and data asynchrony caused by network dependence, communication delay, and software start-stop dead time in the existing dual-machine collaborative testing scheme, while achieving high-precision and repeatable evaluation of photoconductor response uniformity.

[0010] The technical solution adopted by this invention is as follows: This invention provides a single-machine offline automatic testing method for electromagnetic calorimeter optical guide devices, specifically including the following steps:

[0011] S1: Fix the assembled test piece onto the electric slide rail. The test piece includes a scintillator array and a light guide device coupled to the scintillator array.

[0012] S2: Integrate control logic on a computer, and directly drive the motion controller and digitizer of the electric slide rail by calling the hardware driver library to realize device control in a stand-alone offline environment, and the computer is disconnected from the network throughout the test.

[0013] S3: Execute the integrated automatic scanning process, control the electric slide rail to drag the test piece in two-dimensional planar motion according to the preset step length and path, so that the light spot of the excitation source scans the end face of the test piece in sequence;

[0014] S4: During the spot scanning process, whenever the electric slide rail moves to a preset position and stops, the computer immediately triggers the digitizer to collect the signal from the photon detector after the electric slide rail stops. The photon detector is used to receive the scintillation photons output by the photoconductor.

[0015] S5: The digitizer digitizes the collected signals and transmits and stores them in the computer;

[0016] S6: Repeat steps S3 to S5 until the scanning of the entire end face of the test piece is completed, and full-position scanning data is obtained;

[0017] S7: Run a data processing script in the computer to convert the full-position scan data into signal response values ​​and arrange them according to the moving position of the electric slide rail to generate a performance distribution map for evaluating the response uniformity of the optical guide device.

[0018] Furthermore, the preset path in step S3 is a serpentine scanning path, that is, the electric slide rail is controlled to move unidirectionally to the edge in the X direction, then moves one grid in the Y direction, and then moves in the opposite direction in the X direction, and so on until the entire scanning area is covered.

[0019] Furthermore, the hardware driver library in step S2 includes dynamic link library files and function libraries for driving the electric slide rail, and driver files for driving the digitizer; the computer's operating system is Windows, and the entire test is conducted offline.

[0020] Furthermore, the excitation source is a laser, and the method further includes sequentially setting an aperture and a lens at the head of the laser to focus the laser spot to less than or equal to 0.5 mm, and the spot size is smaller than the end face size of a single scintillator in the scintillator array; the preset step size is 0.5 mm to 1 mm.

[0021] Furthermore, the absorber in the test piece is 3D printed using PLA plastic, and the absorber has positioning holes for inserting the scintillator. The two ends of the scintillator are reserved with 3-5 mm for grinding and polishing. The inner wall of the light guide device is attached with a reflective film, and the light guide device is sealed to the absorber to prevent light leakage.

[0022] Further, the generation of the performance distribution map in step S7 specifically includes: normalizing the signal amplitude and filling it into a two-dimensional grid according to the position coordinates, where each grid corresponds to the position of a scintillator, and the color depth or brightness of the grid represents the ratio of the signal response value to the maximum value at that position, and calculating the root mean square (RMS) of the response values ​​of all grids as an evaluation index of the response uniformity of the optical guide device; when the RMS is less than or equal to 3%, the performance of the optical guide device is determined to be qualified.

[0023] This invention also provides a stand-alone offline automatic testing system for electromagnetic calorimeter optical guide devices, used to implement the method described in any of the above-mentioned embodiments, the system comprising:

[0024] A test piece fixing module is used to fix the assembled test piece, which includes a scintillator array and a light guide device;

[0025] The motion control module includes an electric slide rail and its controller, used to drag the test piece to perform two-dimensional planar motion;

[0026] The excitation and acquisition module includes an excitation source, a photon detector, and a digitizer. The excitation source is used to generate a light spot to scan the end face of the test piece. The photon detector is used to receive the scintillation photons output by the photoconductive device and convert them into electrical signals. The digitizer is used to digitize the electrical signals.

[0027] A stand-alone offline control and processing module, specifically a computer integrating all control logic, the computer comprising:

[0028] An integrated drive unit is used to directly control the motion control module and the digitizer by calling the hardware driver library;

[0029] The synchronization control unit is used to control the electric slide rail to move to a preset position and stop during scanning, and then immediately trigger the digitizer to acquire signals, so as to realize the synchronous linkage between movement and acquisition.

[0030] The data processing unit is used to convert the collected full-position scanning data into signal response values ​​and arrange them according to position to generate a performance distribution map, and calculate the root mean square of the response values ​​of all scanning positions as a uniformity evaluation index.

[0031] Furthermore, the synchronization control unit is specifically used to: immediately trigger the digitizer to perform a signal acquisition after controlling the electric slide rail to move to a preset position and stop, and control the electric slide rail to move to the next position after the acquisition is completed, so as to achieve seamless connection between movement and acquisition and eliminate dead time caused by communication between devices and software start and stop.

[0032] Furthermore, in the test piece, the scintillator array is inserted into a 3D-printed absorber, which is made of PLA plastic; the light guide device is 3D-printed and coated with a reflective film inside; one end of the light guide device is connected to the tail of the scintillator array, and the other end is connected to the photon detector; the photon detector is a small-sized photomultiplier tube, which is tightly coupled to the output end of the light guide device and is externally shielded.

[0033] Furthermore, the data processing unit is also used to calculate the root mean square of the response values ​​at all scanning positions, and compare the root mean square with a preset threshold of 3% to determine whether the response uniformity of the optical guide device is qualified.

[0034] The beneficial effects achieved by the present invention using the above solution are as follows:

[0035] 1. A single computer directly controls the electric slide rail and digitizer through a hardware driver library, eliminating the need for a network or remote desktop, thus completely avoiding test interruptions or data misalignment caused by network fluctuations and significantly improving system stability.

[0036] 2. The sliding rail movement and stopping and the digitizer trigger acquisition are designed as a hardware-level synchronous process, which eliminates the communication delay between the two machines and the time consumed by software start and stop, greatly reduces the system dead time, and improves the testing efficiency.

[0037] 3. From scanning path planning and data acquisition to response uniformity analysis, including normalized distribution plots and RMS calculations, everything is done automatically by scripts, avoiding human error. The test results have good repeatability and traceability.

[0038] 4. By adopting a 3D-printed absorber and light guide, and a small-area equivalent testing scheme, combined with an optimized scanning path, the manufacturing cost and testing cycle of the prototype are significantly reduced, making it suitable for rapid iterative evaluation of light guide performance in a laboratory environment.

[0039] 5. The uniformity of the light guide can be intuitively quantified by the normalized response distribution map and the root mean square threshold, providing an objective basis for the optimization of light guide design. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of a small prototype of the optical fiber access device of the present invention;

[0041] Figure 2 This is a flowchart illustrating the operation of the technical solution of the present invention;

[0042] Figure 3 This is the standard flowchart of the present invention;

[0043] Figure 4 This is a schematic diagram of the data processing of the present invention;

[0044] Figure 5 This is a schematic diagram of the electric slide rail motion logic of the present invention. Detailed Implementation

[0045] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0046] like Figure 1-5 As shown Example 1: Test Specimen Preparation

[0047] In this embodiment, a small prototype machine for equivalent testing is first prepared. Since the full-size electromagnetic energy meter is expensive, a small-area equivalent testing method is adopted: the full-size model machine is divided into 9×9 or 6×6 identical areas. Assuming that the performance of each area is consistent, only one area needs to be measured to extrapolate to the whole.

[0048] The absorber is made of PLA plastic and 3D printed. It has 12×12 square through holes pre-drilled as designed, with each hole having a cross-section of 1.0mm×1.0mm. The scintillator is the same model as the full-size detector (with identical optical parameters). After being cut to the length of the absorber, 3-5mm is left at both ends for polishing. The scintillator is inserted into the holes of the absorber, and both ends are polished to an optically smooth finish.

[0049] The light guide is also manufactured using 3D printing, with an ESR high-reflectivity film attached to its inner wall. One end of the light guide is sealed and fixed to the tail of the absorber with an M3 screw, and the contact surface is coated with optical coupling agent and light-shielding. The other end is tightly inserted into a small photomultiplier tube (PMT, model Hamamatsu R9880U-20), and is fixed and shielded from light by wrapping it with black tape. The PMT's power supply line is connected to a high-voltage power supply (CAEN V6534M), and the signal output line is connected to a digitizer (CAEN DT5742B). Example 2: Test System Setup and Standalone Offline Control

[0050] The test system hardware includes:

[0051] Two-dimensional electric slide rails: Zhuoli Hanguang PA150 (X-axis) and PA400-Z (Y-axis), equipped with MC600-2B controller;

[0052] Excitation source: PILAS PIL037-FS laser, wavelength matched with scintillator emission spectrum; 1mm aperture stop and focusing lens are placed close to the laser outlet to make the focused spot diameter ≤0.5mm;

[0053] Single computer: Windows 11 operating system, Python 3.8 or above installed, including electric slide rail driver files (zolix_mc600.dll, .h, .lib and device_mc600.py) and digitizer driver library (CAENDigitizer.py).

[0054] The computer can run offline without any network connection. The control script auto_scan_acquire.py directly drives the slide rail controller and digitizer by calling dynamic link libraries, without any intermediate software or remote desktop. Example 3: Integrated Automatic Scanning and Data Acquisition

[0055] Fix the test piece on the electric slide rail stage, manually coarsely adjust the position so that the laser spot is roughly aligned with the center of the test piece end face, turn on the heuristic to observe the PMT output signal, and adjust the optical path so that the signal amplitude is in the range of 80~100mV.

[0056] Run Read_Position.py to read the current slider coordinates. In auto_scan_acquire.py, set the scan center point CENTER_POS_X and CENTER_POS_Y, set the scan step size to 0.5mm, and the scan range covers the entire 20mm×20mm end face (actually divided into 48×48=2304 points).

[0057] Running `auto_scan_acquire.py` automatically performs a snake-like scan: the slide rail moves one step (0.5mm) in the positive X direction → stops → synchronously triggers the digitizer to acquire the PMT signal → digitizes and stores the data (CSV format, filename waveform_i_j.csv, i and j are point indices) → the slide rail continues to move until the edge in the X direction → the slide rail moves one unit in the Y direction → the slide rail moves in the negative X direction, repeating the cycle. Throughout the process, there is no communication delay or software start / stop waiting between the movement stopping and the acquisition trigger. The single-point acquisition time is determined by the digitizer's own conversion time (in microseconds), saving more than 50% of the "dead time" compared to existing technologies. Example 4: Data Processing and Optical Guide Uniformity Evaluation

[0058] After the scan is complete, run Analysis_code / main / response_analysis_main.py to process all CSV files:

[0059] Extract the peak amplitude (mV) of the waveform at each point.

[0060] Normalize the amplitude of all points (with the maximum amplitude as 100%).

[0061] The normalized amplitude is filled into a 48×48 two-dimensional grid according to the point coordinates to generate a response distribution map. Each grid corresponds to the position of a scintillator. The brighter (or redder) the grid color, the higher the response ratio.

[0062] Calculate the root mean square (RMS) of the response values ​​for all valid points (excluding absorber locations).

[0063] If the RMS is ≤ 3%, the response uniformity of the photoconductor is deemed acceptable; otherwise, the photoconductor design (such as the layout of the reflective film and the shape of the photoconductor) is optimized. In this embodiment, a batch of photoconductors was tested and found to have an RMS of 2.7%, which meets the design specifications. Example 5: Comparison and Verification of Results

[0064] The same optical guide device was tested using the method of this invention and the traditional dual-machine remote desktop method. The comparison results are as follows:

[0065]

[0066] As can be seen from the comparison, the present invention has significant improvements in stability, efficiency and data reliability.

[0067] Extended Implementation

[0068] The above embodiments use electromagnetic calorimeter photoconductor testing as an example, but the method and system of the present invention are not limited to this: the present invention can be used in any scenario that requires automated and high-precision testing of the two-dimensional response uniformity of the scintillator array-photoconductor structure (such as nuclear medicine imaging detectors, other sub-detectors in high-energy physics). The specific models of the electric slide rail, digitizer, and photon detector can be replaced according to actual needs, as long as the corresponding hardware driver library is provided and the control logic of stand-alone offline and synchronous linkage is followed.

[0069] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, material, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, material, or apparatus.

[0070] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A single-machine offline automatic testing method for electromagnetic calorimeter optical guide devices, characterized in that, Specifically, the following steps are included: S1: Fix the assembled test piece onto the electric slide rail. The test piece includes a scintillator array and a light guide device coupled to the scintillator array. S2: Integrate control logic on a computer, and directly drive the motion controller and digitizer of the electric slide rail by calling the hardware driver library to realize device control in a stand-alone offline environment, and the computer is in a state of being disconnected from the network throughout the test. S3: Execute the integrated automatic scanning process, control the electric slide rail to drag the test piece in two-dimensional planar motion according to the preset step length and path, so that the light spot of the excitation source scans the end face of the test piece in sequence; S4: During the spot scanning process, whenever the electric slide rail moves to a preset position and stops, the computer immediately triggers the digitizer to collect the signal from the photon detector after the electric slide rail stops. The photon detector is used to receive the scintillation photons output by the photoconductor. S5: The digitizer digitizes the collected signals and transmits and stores them in the computer; S6: Repeat steps S3 to S5 until the scanning of the entire end face of the test piece is completed, and full-position scanning data is obtained; S7: Run a data processing script in the computer to convert the full-position scan data into signal response values ​​and arrange them according to the moving position of the electric slide rail to generate a performance distribution map for evaluating the response uniformity of the optical guide device.

2. The offline automatic testing method for an electromagnetic calorimeter optical guide device according to claim 1, characterized in that: The preset path in step S3 is a serpentine scanning path, which means that the electric slide rail is controlled to move unidirectionally to the edge in the X direction, then moves one grid in the Y direction, and then moves in the opposite direction in the X direction, and so on until the entire scanning area is covered.

3. The offline automatic testing method for an electromagnetic calorimeter optical guide device according to claim 1, characterized in that: The hardware driver library in step S2 includes dynamic link library files and function libraries for driving the electric slide rail, and driver files for driving the digitizer; the computer's operating system is Windows, and the entire test is conducted offline.

4. The offline automatic testing method for an electromagnetic calorimeter optical guide device according to claim 1, characterized in that: The excitation source is a laser, and the method further includes sequentially setting an aperture and a lens at the head of the laser to focus the laser spot to less than or equal to 0.5 mm, and the spot size is smaller than the end face size of a single scintillator in the scintillator array; the preset step size is 0.5 mm to 1 mm.

5. The offline automatic testing method for an electromagnetic calorimeter optical guide device according to claim 1, characterized in that: The absorber in the test piece is 3D printed from PLA plastic. The absorber has positioning holes for inserting a scintillator. The two ends of the scintillator are reserved with 3-5 mm for grinding and polishing. The inner wall of the light guide device is attached with a reflective film, and the light guide device is sealed to the absorber to prevent light leakage.

6. The offline automatic testing method for a single-unit electromagnetic calorimeter optical guide device according to claim 1, characterized in that: The generation of the performance distribution map in step S7 specifically includes: normalizing the signal amplitude and filling it into a two-dimensional grid map according to the position coordinates, where each grid corresponds to the position of a scintillator, and the color depth or brightness of the grid represents the ratio of the signal response value to the maximum value at that position, and calculating the root mean square (RMS) of the response values ​​of all grids as an evaluation index of the response uniformity of the optical guide device; when the RMS is less than or equal to 3%, the performance of the optical guide device is determined to be qualified.

7. A stand-alone offline automatic testing system for electromagnetic calorimeter optical guide devices, characterized in that, The system for implementing the method of any one of claims 1 to 6 comprises: A test piece fixing module is used to fix the assembled test piece, which includes a scintillator array and a light guide device; The motion control module includes an electric slide rail and its controller, used to drag the test piece to perform two-dimensional planar motion; The excitation and acquisition module includes an excitation source, a photon detector, and a digitizer. The excitation source is used to generate a light spot to scan the end face of the test piece. The photon detector is used to receive the scintillation photons output by the photoconductive device and convert them into electrical signals. The digitizer is used to digitize the electrical signals. A stand-alone offline control and processing module, specifically a computer that integrates all control logic; The computer includes: An integrated drive unit is used to directly control the motion control module and the digitizer by calling the hardware driver library; The synchronization control unit is used to control the electric slide rail to move to a preset position and stop during scanning, and then immediately trigger the digitizer to acquire signals, so as to realize the synchronous linkage between movement and acquisition. The data processing unit is used to convert the collected full-position scanning data into signal response values ​​and arrange them according to position to generate a performance distribution map, and calculate the root mean square of the response values ​​of all scanning positions as a uniformity evaluation index.

8. The single-unit offline automatic testing system for electromagnetic calorimeter optical guide devices according to claim 7, characterized in that: The synchronization control unit is specifically used to immediately trigger the digitizer to perform a signal acquisition after controlling the electric slide rail to move to a preset position and stop, and to control the electric slide rail to move to the next position after the acquisition is completed, so as to achieve seamless connection between movement and acquisition and eliminate dead time caused by communication between devices and software start and stop.

9. The single-unit offline automatic testing system for electromagnetic calorimeter optical guide devices according to claim 7, characterized in that: In the test piece, the scintillator array is inserted into a 3D-printed absorber, which is made of PLA plastic. The light guide device is 3D printed and coated with a reflective film. One end of the light guide device is connected to the tail of the scintillator array, and the other end is connected to the photon detector. The photon detector is a small-sized photomultiplier tube and is tightly coupled to the output end of the light guide device. It is externally shielded.

10. The single-unit offline automatic testing system for electromagnetic calorimeter optical guide devices according to claim 7, characterized in that: The data processing unit is also used to calculate the root mean square of the response values ​​at all scanning positions and compare the root mean square with a preset threshold of 3% to determine whether the response uniformity of the optical guide device is qualified.

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