CN-122017919-A - Pulse charged particle beam dose monitoring system and monitoring method thereof

CN122017919ACN 122017919 ACN122017919 ACN 122017919ACN-122017919-A

Abstract

The invention relates to a pulse charged particle beam dose monitoring system and a monitoring method thereof, wherein the pulse charged particle beam dose monitoring system comprises an ACCT sensor, a signal conditioning module, a high-speed data acquisition module and a data processing and interacting module, the ACCT sensor is arranged on a beam vacuum pipeline, the output end of the ACCT sensor is connected to the signal conditioning module, the output end of the signal conditioning module is connected to the high-speed data acquisition module, the output end of the high-speed data acquisition module is connected with the data processing and interacting module, the system calibration is carried out to obtain a conversion coefficient k in a preset signal-dose conversion relation, the system is adopted to carry out real-time monitoring and analysis of a dose-time spectrum, and the dose-time spectrum of a charged particle beam is obtained. By adopting the system and the method disclosed by the embodiment of the invention, the real-time and nondestructive monitoring of the beam pulse time structure and the corresponding dose-time distribution can be realized, thereby providing support and guarantee for accurate dose control and safe treatment.

Inventors

CHEN JIAHANG
GAO FEI
NI NING
WANG FEIFEI
DING YUYANG

Assignees

中国原子能科学研究院

Dates

Publication Date: 20260512
Application Date: 20251231

Claims (10)

1. The pulse charged particle beam dose monitoring system is characterized by comprising an ACCT sensor, a signal conditioning module, a high-speed data acquisition module and a data processing and interacting module, wherein the ACCT sensor is arranged on a beam vacuum pipeline, the output end of the ACCT sensor is connected to the input end of the signal conditioning module, the output end of the signal conditioning module is connected to an input channel of the high-speed data acquisition module, and the output end of the high-speed data acquisition module is connected with the data processing and interacting module; the ACCT sensor is used for sensing beam pulses in a non-interception mode and outputting broadband weak current signals corresponding to the time change rate of the beam intensity; The signal conditioning module is used for conditioning a broadband weak current signal output by the ACCT sensor into a voltage signal with high signal-to-noise ratio; The high-speed data acquisition module is used for acquiring and digitizing the conditioned voltage signal at a preset sampling frequency to obtain a high-resolution discrete sequence of the beam intensity changing along with time; The data processing and interacting module is used for converting the beam intensity data into air kerma or absorbed dose according to a preset signal-dose conversion relation, and further reconstructing and displaying waveforms of dose distribution along with time in real time, so that a beam dose-time spectrum is obtained.
2. The pulsed charged-particle beam dose monitoring system of claim 1 wherein said signal conditioning module comprises a transimpedance amplification circuit and a low pass filter circuit; the transimpedance amplifying circuit is used for converting a broadband weak current signal output by the broadband ACCT sensor into a voltage signal; the low-pass filter circuit is used for inhibiting high-frequency noise of the voltage signal, and effectively improving the signal-to-noise ratio of the voltage signal on the basis of keeping the original time characteristic.
3. A pulsed charged-particle beam dose monitoring system according to claim 2, wherein the feedback resistor R f is sized according to the beam intensity and the number of turns in the wideband ACCT sensor coil.
4. The pulsed charged-particle beam dose monitoring system of claim 1 wherein said high-speed data acquisition module comprises a high-speed ADC and an FPGA device.
5. A pulsed charged-particle beam dose monitoring system according to claim 1, wherein the high-speed data acquisition module comprises a digital oscilloscope.
6. A pulsed charged-particle beam dose monitoring system according to claim 1, wherein the data processing and interaction module is further configured to automatically extract dose-related key parameters including pulse peak dose rate, pulse width, rise time, fall time, and total single pulse dose.
7. A pulsed charged particle beam dose monitoring system according to claim 6, wherein said predetermined signal-to-dose conversion relationship in said data processing and interaction module is Where D is the dosage, k is the conversion factor, V out (t) is the output voltage of the transimpedance amplifier, R f is a feedback resistor, I ind (t) is an induced current, I ind (t) = I b (t) /N, I b (t) is beam intensity, and N is the number of turns of the ACCT sensor coil.
8. A pulsed charged particle beam dose monitoring method employing a pulsed charged particle beam dose monitoring system according to any one of claims 1-7, said method comprising the steps of: S1, performing system calibration to obtain a conversion coefficient k in a preset signal-dose conversion relation in a data processing and interaction module; S2, based on the obtained conversion coefficient k, adopting a system to monitor and analyze the dose-time spectrum in real time.
9. A pulsed charged particle beam dose monitoring method according to claim 8 wherein step S1 comprises the sub-steps of: S11, leading out a single or a series of beam pulses with known beam intensity I b (t), measuring the cumulative absorbed dose of the beam pulses with known beam intensity I b (t), and taking the measured cumulative absorbed dose of the beam pulses as a reference dose D ref ; S12, calculating total beam current load Q total =∫I b (t) dt, and S13, calculating a conversion coefficient k k=D ref /Q total based on the total beam current load Q total and the reference dose D ref .
10. A pulsed charged particle beam dose monitoring method according to claim 8 wherein step S2 comprises the sub-steps of: S21, collecting beam pulses of charged particles, and obtaining a voltage time sequence V out [ n ] of the beam intensity changing along with time from a high-speed data collecting module; s22, carrying out beam reconstruction according to a preset formula based on the obtained voltage time sequence V out [ n ] to obtain a discrete beam intensity sequence I b [ n ]; S23, based on a conversion coefficient k, performing dose conversion to convert a beam intensity sequence I b [ n ] into a dose rate sequence DoseRate [ n ] =k×I b [ n ]; S24, generating DoseRate n curves which change along with time, and obtaining the dose-time spectrum of the charged particle beam.

Description

Pulse charged particle beam dose monitoring system and monitoring method thereof Technical Field The invention belongs to the field of ionizing radiation metering, and particularly relates to a pulse charged particle beam dose monitoring system and a pulse charged particle beam dose monitoring method. Background Pulsed electron beams, because of their advantages of easy acceleration, adjustable dose rate, etc., present significant value in certain application scenarios, especially in generating pulsed photon beams and in several specialized applications. The pulsed electron beam generates bremsstrahlung radiation through targeting, and can efficiently generate pulsed photon beams (such as X-rays and gamma-rays). In medical imaging, the pulse photon beam has microsecond time resolution, can be used for capturing high-definition images of organ dynamic processes such as heart pulsation and the like, and can be used for penetrating thick-wall metal components in the field of industrial detection to realize high-speed and real-time defect detection, such as online flaw detection of pipeline welding seams. In scientific research, the pulse photon beam can also be used for simulating a high-energy photon environment in the physical process of a celestial body and researching the interaction mechanism of photons and substances. Because of the instantaneous high dose rate and specific temporal structure, pulsed proton and heavy ion beams have become key technologies in FLASH radiotherapy and related scientific research. In FLASH radiotherapy, pulsed proton/heavy ion beams can significantly reduce damage to normal tissues while maintaining a high tumor killing effect by virtue of an instantaneous high dose rate, i.e. a so-called FLASH effect is realized. By combining the special Bragg peak energy release characteristic of the heavy ion beam and the time structure which can be synchronous with physiological activities such as respiration, the technology can realize accurate radiotherapy with double dimensions of space and time, and is particularly suitable for clinical treatment of refractory tumors. In the scientific research aspect, the pulse particle beams can be used for simulating space radiation, nuclear accident scenes and extreme material irradiation environments, and provide a key experimental means for radiation biology, material science and basic physical research. Pulsed charged particle beam technology presents a significant challenge in terms of time structure measurement. The application of the method requires the accurate representation of the beam time dimension, the measurement precision is required to reach the sub-millisecond level or even the nanosecond level, and the stability of radiation performance parameters during the pulse period is ensured. In the prior art, steady-state beam current is mainly monitored, and the dynamic characteristic of pulse beams cannot be effectively responded, so that the dynamic characteristic of the pulse beams becomes a technical bottleneck for restricting the development of the pulse beams. At present, the monitoring technology suitable for pulse beam is mainly divided into two types of interception type and non-interception type. The interception type monitoring is represented by an ionization chamber, and the device can accurately measure the total dose of a single pulse, but because the charge collection time is far longer than the pulse duration and the response speed is slow, the instantaneous change of the dose inside the pulse can not be captured, so that a key 'dose-time spectrum' is difficult to obtain, and the dynamic dose control capability under a high-dose rate scene is limited. The off-line measuring equipment such as the thermoluminescent dosage sheet can only provide accumulated dosage information, and cannot realize real-time data output, so that the requirements of 'real-time monitoring' and 'pulse time structure analysis' in pulse beam application such as real-time dosage feedback in FLASH radiotherapy and on-line defect judgment in industrial flaw detection cannot be met. Disclosure of Invention The invention aims to provide a pulse charged particle beam dose monitoring system and a pulse charged particle beam dose monitoring method, which can monitor the time structure of a pulse charged particle beam in real time on the premise of not interfering beam current and analyze and obtain fine dose-time distribution (namely dose-time spectrum) during the pulse period, thereby providing support and guarantee for accurate dose control and safe treatment. Specifically, by constructing a quantitative correlation model between non-interception equipment signals and a dose-time spectrum, accurate inversion from beam intensity time distribution to dose time distribution is realized, and strict requirements of high-dose rate and high-stability application scenes such as heavy ion FLASH radiotherapy and high-energy photon scientific research experiments on