阅读说明：本技术 一种低探测下限的辐射剂量测量方法 (radiation dose measuring method with low detection lower limit ) 是由 贺三军 赵修良 陈斌 赵健为 刘丽艳 周超 于 2019-08-06 设计创作，主要内容包括：本发明公开了一种低探测下限的辐射剂量测量方法,包括步骤：一,将现场食盐制作成多个剂量元件；二,利用脉冲光致发光技术对辐射过不同剂量的各剂量元件进行检测,得到不同剂量元件对应的食盐OSL信号；三,对各食盐OSL信号和对应的剂量进行线性拟合,得到不同测量参数下的线性拟合度；四,选取最佳线性拟合度对应的脉冲光致发光技术参数,并得到该脉冲光致发光技术参数下食盐OSL信号与剂量之间的对应关系；五,在步骤四中得到的脉冲光致发光技术参数下,测量现场食盐OSL信号,反推计算食盐吸收剂量。本发明降低了光致发光技术测量食盐吸收辐射剂量的探测下限,能够有效测量紧急核泄漏事件中现场食盐的辐射剂量,为测量核事故中公众剂量提供技术基础。(the invention discloses a radiation dose measuring method with low detection lower limit, which comprises the following steps: firstly, preparing on-site table salt into a plurality of dosage elements; secondly, detecting the dosage elements irradiated with different dosages by using a pulse photoluminescence technology to obtain salt OSL signals corresponding to the dosage elements; thirdly, carrying out linear fitting on each salt OSL signal and the corresponding dose to obtain the linear fitting degree under different measurement parameters; selecting a pulse photoluminescence technical parameter corresponding to the optimal linear fitting degree, and obtaining a corresponding relation between the salt OSL signal and the dosage under the pulse photoluminescence technical parameter; and fifthly, measuring the on-site salt OSL signal under the pulse photoluminescence technical parameters obtained in the step four, and calculating the salt absorption dose by reverse calculation. The invention reduces the detection lower limit of the photoluminescence technology for measuring the radiation dose absorbed by the salt, can effectively measure the radiation dose of the salt on site in the emergency nuclear leakage event, and provides a technical basis for measuring the public dose in the nuclear accident.)

1. A radiation dosimetry method with a low lower detection limit, comprising the steps of:

Firstly, manufacturing on-site table salt into a plurality of dosage elements;

Detecting the dosage elements irradiated with different dosages by using a pulse photoluminescence technology to obtain salt OSL signals corresponding to the dosage elements; in the detection process, pulse intervals and pulse numbers are kept unchanged, and the pulse width is changed for multiple times;

performing linear fitting on the salt OSL signals of the dosage elements and the corresponding dosages to obtain linear fitting degrees under different measurement parameters;

Selecting a pulse photoluminescence technical parameter corresponding to the optimal linear fitting degree from the linear fitting degrees corresponding to different measurement parameters, and obtaining the corresponding relation between the salt OSL signal and the dosage under the pulse photoluminescence technical parameter;

And step five, measuring the on-site salt OSL signal under the pulse photoluminescence technical parameters obtained in the step four, and calculating the salt absorption dose by reverse extrapolation according to the corresponding relation between the salt OSL signal and the dose under the pulse photoluminescence technical parameters obtained in the step four.

2. A low detection limit radiation dosimetry method according to claim 1 wherein said step one comprises:

Collecting on-site salt and forming a plurality of salt samples;

A plurality of table salt samples are respectively irradiated with different doses to form a plurality of dose elements.

3. A low detection limit radiation dosimetry method according to claim 2, further comprising: the salt samples were photo-annealed prior to irradiation of the test samples.

4. A radiation dosimetry method with low detection limit according to claim 2, wherein the doses of radiation to the plurality of table salt samples are respectively: 1mGy, 10mGy, 100mGy, 200mGy, 400mGy, 800mGy, 1000mGy, 2000mGy, 4000mGy, 8000mGy, 10000 mGy.

5. The radiation dose measuring method with low detection limit as claimed in claim 1, wherein in the second step, the pulse interval is kept constant at 50ms, the pulse number is kept constant at 50ms, and the pulse width is adjusted to 1ms, 5ms, 10ms, 20ms, 30ms, 40ms or 50ms during the detection.

6. A radiation dosimetry measurement method with low detection limit according to claim 1, wherein in step four, linear fitting is performed using Origin software.

Technical Field

The invention belongs to the technical field of nuclear radiation dose measurement, and particularly relates to a radiation dose measuring method with a low detection lower limit.

Background

Under the emergency nuclear leakage accident, people cannot directly obtain the ionizing radiation dose suffered by the people through the reading of the personal dosimeter because the people cannot carry the personal dosimeter of the ionizing radiation, and a retrospective dose method is needed to be adopted to measure the radiation dose of the people by using materials replacing the personal dosimeter. Common salt is distributed all over the world and can be easily collected in each household, workplaces, restaurants and other occasions, and the main component NaCl of the common salt has a crystal structure and the characteristics of a photoluminescence material and can be used as a nuclear accident dosage material.

In the retrospective dose method, the photoluminescence technology (Optical simulation luminescence) is widely applied to the accident dose measurement due to the advantages of no need of heating in the whole Optical measurement process, high sensitivity, high reading speed, repeated reading, wide dynamic linear range and the like.

Photoluminescence technology is classified into a constant intensity optical excitation mode (abbreviated as CW-OSL), a linear modulation optical excitation mode (abbreviated as LM-OSL), and a pulsed light source excitation mode (abbreviated as POSL) according to the excitation modes.

Disclosure of Invention

The invention aims to provide a radiation dose measuring method with low detection lower limit, aiming at the defects of the prior art, the pulse photoluminescence technology is adopted to measure the absorption dose of the salt, the detection lower limit of the photoluminescence technology for measuring the absorption radiation dose of the salt is reduced, the radiation dose of the salt on site in the emergency nuclear leakage event can be effectively measured, and a technical basis is provided for measuring the public dose in the nuclear accident.

In order to solve the technical problems, the technical scheme adopted by the invention is as follows:

A radiation dose measuring method with low detection lower limit is characterized by comprising the following steps:

Firstly, manufacturing on-site table salt into a plurality of dosage elements;

Detecting the dosage elements irradiated with different dosages by using a pulse photoluminescence technology to obtain salt OSL signals corresponding to the dosage elements; in the detection process, pulse intervals and pulse numbers are kept unchanged, and the pulse width is changed for multiple times;

performing linear fitting on the salt OSL signals of the dosage elements and the corresponding dosages to obtain linear fitting degrees under different measurement parameters;

selecting a pulse photoluminescence technical parameter corresponding to the optimal linear fitting degree from the linear fitting degrees corresponding to different measurement parameters, and obtaining the corresponding relation between the salt OSL signal and the dosage under the pulse photoluminescence technical parameter;

and step five, measuring the on-site salt OSL signal under the pulse photoluminescence technical parameters obtained in the step four, and calculating the salt absorption dose by reverse extrapolation according to the corresponding relation between the salt OSL signal and the dose under the pulse photoluminescence technical parameters obtained in the step four.

As a preferred mode, the first step includes:

Collecting on-site salt and forming a plurality of salt samples;

A plurality of table salt samples are respectively irradiated with different doses to form a plurality of dose elements.

further, still include: the salt samples were photo-annealed prior to irradiation of the test samples.

In a preferred embodiment, in the second step, the pulse interval is kept constant at 50ms, the pulse number is kept constant at 50ms, and the pulse width is adjusted to 1ms, 5ms, 10ms, 20ms, 30ms, 40ms, or 50ms during the detection.

As a preferable mode, the doses of the radiation to the plurality of salt samples are respectively as follows: 1mGy, 10mGy, 100mGy, 200mGy, 400mGy, 800mGy, 1000mGy, 2000mGy, 4000mGy, 8000mGy, 10000 mGy.

In a preferred embodiment, in the fourth step, the linear fitting is performed by using Origin software.

the CW-OSL and LM-OSL methods need to fully excite the dose information in the salt crystal, the lower limit of the dose response can only reach 1mGy, the POSL method can only excite partial dose information in the salt crystal compared with the CW-OSL and LM-OSL methods, OSL counting of the background of the salt can be reduced by controlling the excitation frequency, and the lower limit of the dose response can reach 1 uGy.

Compared with the prior art, the method adopts the pulse photoluminescence technology to measure the salt absorption dose, reduces the detection lower limit of the photoluminescence technology to measure the salt absorption radiation dose, can effectively measure the radiation dose of the salt on site in the emergency nuclear leakage event, and provides a technical basis for measuring the public dose in the nuclear accident.

Drawings

FIG. 1 is a flow chart of an embodiment of the present invention.

FIG. 2 is a timing diagram of the measurement according to the present invention.

Detailed Description

In this example, the common salt OSL signal was measured using an Inlight200 model photoluminescence dosimetry system from blue Dalbergia USA.

As shown in fig. 1, an embodiment of the present invention includes the following steps:

A. making in situ salt into dosage elements:

Collecting on-site salt and forming a plurality of salt samples;

Performing light annealing treatment on the salt sample to ensure that the background dosage of the salt is consistent;

different doses were irradiated on multiple saline samples: 1mGy, 10mGy, 100mGy, 200mGy, 400mGy, 800mGy, 1000mGy, 2000mGy, 4000mGy, 8000mGy, 10000mGy, thereby forming a plurality of dosage elements.

B. The four-element salt container is manufactured by using a 3D printing technology, and can enter a measuring channel of an InLight200A type dosage measuring system to achieve the purpose of measuring a salt photoluminescence signal.

C. The irradiated salt dosage element was placed in a four-component salt container with transparent adhesive tape on both sides to secure the salt dosage element.

D. The four-element salt container was placed in a dose measuring system model InLight200A and the dose elements were tested using pulsed photoluminescence. In the detection process, the pulse excitation time t of the measurement system needs to be set₁photon count time t₂the number of excitation pulses n is detected every time. Firstly, setting the pulse width, pulse interval and pulse number as 1ms, 50ms and 50 respectively, carrying out one-time detection on the salt, and only exciting dose information of the internal part of the salt crystal to obtain the relation between the photoluminescence signal and the dose of the salt; then, t is held₂The pulse width was varied to 5ms, 10ms, 20ms, 30ms, 40ms, 50ms for 50ms and n was constant for 50ms, and the number of salt photoluminescence signals was recorded to obtain the salt OSL signals for the different dosage elements. Fig. 2 shows a measurement timing chart of the present embodiment.

E. The salt OSL signal of each dosage element and the corresponding dosage are linearly fitted by Origin software to obtain the linear fitting degree under different measurement parameters.

F. selecting the pulse photoluminescence technical parameter corresponding to the optimal linear fitting degree from the corresponding linear fitting degrees under different measurement parameters, and obtaining the corresponding relation between the salt OSL signal and the dosage under the pulse photoluminescence technical parameter.

G. and F, measuring the salt OSL signal irradiated with a certain dose on site under the pulse photoluminescence technical parameters obtained in the step F, and calculating the salt absorption dose by reverse extrapolation according to the corresponding relation between the salt OSL signal and the dose under the pulse photoluminescence technical parameters obtained in the step F.

according to the formula:

The minimum detectable lower limit of the method of the invention can be calculated and can reach 1 uGy.

wherein, I_OSLMeasured OSL signal strength for the system; delta is the standard deviation of the background count within the integration time delta t; 3 δ is the evaluation of MDD at a confidence level of 99.7%.

While the present invention has been described with reference to the embodiments shown in the drawings, the present invention is not limited to the embodiments, which are illustrative and not restrictive, and it will be apparent to those skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope of the invention as defined in the appended claims.