Standard quartz sample preparation method for calibration of luminescence dating instruments

Abstract

The application discloses a preparation method of a standard quartz sample for calibration of a luminescence dating instrument, and relates to the technical field of luminescence dating, and comprises the following steps: preparing a quartz glass front wall, a quartz glass back wall and a ring-shaped pad; placing the ring-shaped pad between the quartz glass front wall and the quartz glass back wall, placing a quartz sample in a center hole of the ring-shaped pad, and obtaining a completed loading device; wrapping the loading device with aluminum foil, placing the loading device on a special support, and placing the loading device at a measurement point of a reference radiation field; measuring an air kerma rate at the measurement point; calculating a conversion coefficient from the air kerma to a quartz absorbed dose; calculating the quartz absorbed dose; using a single factor variance analysis method of a luminescence dating instrument to evaluate the uniformity of the quartz sample; and taking out the quartz sample at different times after irradiation and respectively reading the quartz absorbed dose to evaluate the stability of the quartz absorbed dose. The application can make the loading of the standard quartz sample more convenient, and the obtained dose is more accurate.

Description

Technical Field

[0001] This invention relates to the field of luminescence dating technology, and in particular to a method for preparing a standard quartz sample for calibrating a luminescence dating instrument. Background Technology

[0002] After being buried, minerals accumulate luminescence (SLU) signals due to the ionizing radiation generated by the decay of radioactive substances such as uranium, thorium, and potassium in the environment. These SLU signals can be excited by heating or irradiating the mineral particles with a light beam in the laboratory. Since the SLU signal of a mineral is positively correlated with the radiation energy (dose) it receives, a functional relationship between the SLU signal and the radiation dose can be established. The equivalent dose can then be calculated using the measured SLU signal, and divided by the environmental dose rate to obtain the age of the mineral. This process is called luminescence dating.

[0003] The method for establishing a functional relationship between luminescence signal and radiation dose is to irradiate the sample multiple times with a determined dose using the built-in beta radiation source in the luminescence dating instrument, and then measure the corresponding luminescence signal. Multiple irradiations are performed by controlling the sample under the beta radiation source within the instrument for a specific irradiation time (generally in seconds). Since the radioactivity and dose rate of the radiation source gradually decrease over time, dose calibration is required using a quartz sample (i.e., standard quartz) that has been independently irradiated with a known equivalent dose (absorbed dose) to obtain the accurate dose rate of the instrument's built-in radiation source.

[0004] For traditional multi-particle (single-slab) optically stimulated luminescence (OSL) dating, the calibration of the laboratory radiation source dose rate is based on multi-particle standard quartz. In recent years, with the advancement of dating technology, single-particle OSL dating methods using quartz and potassium feldspar have been gradually improved. This method can determine the degree of aging before sample deposition and the mixing of mineral particles from different depositional processes. In principle, each mineral particle can be assigned a depositional age, making this method far more efficient than single-slab OSL dating. Therefore, this method is increasingly widely used, especially suitable for aging samples from complex depositional environments (such as archaeological site deposits, cave sediments, glacial sediments, ancient lake shores, and river terraces). The calibration of the dose rate of the built-in β-radiation source in the single-particle method OSL dating instrument also requires single-particle testing of standard quartz, placing more stringent requirements on the consistency of dose among standard quartz particles.

[0005] Currently, the standard quartz samples used for calibrating luminescent dating instruments mainly come from the Risø laboratory in Denmark. No domestic research institutions have yet developed standard quartz samples. However, their latest research shows that the dosage of standard quartz produced before October 2019 was underestimated by about 8% (Autzen et al., 2022). This result has caused serious problems for all luminescent dating laboratories. Summary of the Invention

[0006] The purpose of this invention is to provide a method for preparing standard quartz samples for calibration of an stimulated luminescence dating instrument, so as to solve the problems existing in the above-mentioned related technologies, facilitate sample loading, and make the dosage of standard quartz more accurate.

[0007] To achieve the above objectives, the present invention provides the following solution:

[0008] This invention discloses a method for preparing a standard quartz sample for calibration of an stimulated luminescence dating instrument, comprising the following steps:

[0009] Step 1: Preparation of the loading device: Prepare a quartz glass front wall and a quartz glass back wall. Both the front and back walls are flat and used to sandwich the granular quartz sample in the middle. The front wall is closer to the radiation source than the back wall. Prepare an annular pad, which is placed between the front and back walls. The quartz sample is placed in the central hole of the annular pad.

[0010] Step 2, Quartz loading: Place the annular pad on the front side of the back wall of the quartz glass, place the quartz sample in the central hole of the annular pad, and place the front wall of the quartz glass on the front side of the annular pad.

[0011] Step 3, Quartz Irradiation: The loading device is wrapped in aluminum foil, placed on a special support, and positioned at the measurement point of the reference radiation field for irradiation.

[0012] Step 4: Parameter Evaluation: Measure the air kerma rate at the measurement point;

[0013] Step 5: Calculate the conversion coefficient from air kerma to quartz absorbed dose;

[0014] Step 6: Calculate the absorbed dose of the quartz sample based on the air kerma rate, conversion coefficient, and irradiation time;

[0015] Step 7: After grouping the prepared quartz samples, use an illuminometer to measure them; use one-way ANOVA to calculate the ratio of between-group variance to within-group variance to evaluate the homogeneity of the quartz samples.

[0016] Step 8: Place the irradiated quartz sample in a shielded box, remove it at different times after irradiation, and perform measurements. Use linear regression to fit the sample, calculate the slope and standard deviation of the linear fitting equation, and evaluate the stability of the quartz absorbed dose by the difference between the slope and 0.

[0017] Preferably, in step one, if the radiation source is Cs-137 with an energy of 662 keV, the thickness of the front wall of the quartz glass is at least 0.55 mm; if the radiation source is Co-60 with an energy of 1.25 MeV, the thickness of the front wall of the quartz glass is at least 2 mm, and the thickness of the back wall of the quartz glass is at least 0.5 mm.

[0018] Preferably, the thickness of the annular pad is no more than 1 mm, so that the loading thickness of the quartz sample does not exceed 1 mm.

[0019] Preferably, the central hole of the annular pad is a square hole or a round hole.

[0020] Preferably, the lower end of the loading device is fixed to a special bracket or the upper end is suspended on a special bracket.

[0021] Optionally, the special bracket includes a pair of parallel first vertical plates and a pair of parallel second vertical plates; the upper end of the first vertical plate is provided with a first upper slot, and the lower end of the first vertical plate is provided with two first lower slots; the upper end of the second vertical plate is provided with two second upper slots; the first vertical plate and the second vertical plate are perpendicular to each other; the two first lower slots of the first vertical plate are respectively inserted into the second upper slots of the two second vertical plates, and the lower end of the loading device is inserted into the first upper slot to fix the lower end of the loading device to the special bracket.

[0022] Optionally, the special support includes a pair of parallel first vertical plates, a pair of parallel second vertical plates, and a third vertical plate; the upper end of the first vertical plate is provided with a first upper slot, and the lower end of the first vertical plate is provided with two first lower slots; the upper end of the second vertical plate is provided with two second upper slots; the first vertical plate and the second vertical plate are perpendicular to each other; the two first lower slots of the first vertical plate are respectively inserted into the second upper slots of the two second vertical plates; the two ends of the third vertical plate are respectively inserted into the first upper slots of the two first vertical plates, and the upper end of the loading device is connected to the third vertical plate by a suspension line to suspend the upper end of the loading device on the special support.

[0023] Preferably, in step five, a corresponding model is established using Monte Carlo software, and a standard quartz integration region or detector is placed in the corresponding area to simulate the conversion coefficient of air kerma under monoenergetic photons to absorbed dose. Then, the energy spectrum of the irradiated radiation quality is integrated through the fluence spectrum and the conversion coefficient of monoenergetic photons to obtain the average energy spectrum value of the conversion coefficient.

[0024] Preferably, in step five, a corresponding model is established using Monte Carlo software, the actual energy spectrum data at the radiation field measurement point is input, the air kerma and the absorbed dose of quartz are calculated respectively, and the conversion coefficient from air kerma to absorbed dose under radiation quality is directly obtained.

[0025] Preferably, in step seven, the quartz sample is divided into different samples; a portion is taken from each sample and placed on aluminum disks in 10 luminescent dating instruments for measurement; a one-way ANOVA method is used to determine whether there is a systematic bias between the measurements by comparing the between-group variance and the within-group variance. If the ratio of the between-group variance to the within-group variance is less than the critical value of the statistical test, the quartz sample is considered to be homogeneous.

[0026] Compared with related technologies, the present invention achieves the following technical effects:

[0027] This invention uses two flat pieces of quartz glass to sandwich a quartz sample in the middle, so that the quartz sample is distributed in a flat shape, reducing mutual occlusion of the quartz samples, thereby improving the consistency of the absorbed dose of the quartz sample.

[0028] This invention specifies requirements for the thickness of the quartz glass. If the radiation source is Cs-137 with an energy of 662 keV, the thickness of the front wall of the quartz glass must be at least 0.55 mm. If the radiation source is Co-60 with an energy of 1.25 MeV, the thickness of the front wall of the quartz glass must be at least 2 mm, and the thickness of the back wall of the quartz glass must be at least 0.5 mm. This is to ensure that the quartz sample is irradiated in a state of charged particle equilibrium and to ensure that the scattered particles in the back area of ​​the quartz sample can be compensated when irradiated, which is more conducive to the stable assessment of the absorbed dose of the quartz sample.

[0029] This invention designs two layers of quartz glass plates with an annular pad in the middle. Quartz particles are laid flat in the central hole of the annular pad, so that the front and back walls of the quartz glass are attached to the annular pad from both sides, which facilitates the uniform spreading and removal of granular quartz samples.

[0030] This invention uses quartz glass, which has a smaller mass-energy absorption coefficient difference from that of the quartz sample, as the loading device material. This ensures that the flux spectrum of the radiation changes less when it passes through the irradiation device and when it passes through the quartz sample, resulting in more accurate and reliable evaluation values.

[0031] The present invention uses aluminum foil to wrap the loading device to shield it from light. The aluminum foil has a better light shielding effect and its composition is known, so its influence on the absorbed dose of quartz sample can be accurately assessed, thus making the quartz absorbed dose value accurate.

[0032] In a preferred embodiment of the present invention, the quartz sample and loading device can be placed naked in the radiation field for irradiation by fixing the lower end or hoisting the upper end, so as to ensure that the quartz sample is not affected by backscattering and make the measurement results more accurate and reliable.

[0033] In a preferred embodiment of the present invention, multiple calculation methods can be selected when calculating the conversion coefficient, which provides high flexibility. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of the present invention or related technologies, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 This is a schematic diagram of a method for preparing standard quartz samples for calibrating an stimulated luminescence dating instrument according to an embodiment of the present invention;

[0036] Figure 2 A schematic diagram illustrating an assembly method of a special support frame and loading device;

[0037] Figure 3 A graph showing the relationship between unit dose and depth under Cs-137 irradiation conditions;

[0038] Figure 4 This is a graph showing the relationship between unit dose and depth under Co-60 irradiation conditions.

[0039] In the diagram: 1-loading equipment; 2-special support; 3-lifting line; 21-first vertical plate; 22-second vertical plate; 23-third vertical plate. Detailed Implementation

[0040] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] The purpose of this invention is to provide a method for preparing standard quartz samples for calibration of an stimulated luminescence dating instrument, so as to solve the problems existing in the above-mentioned related technologies and make the dosage of standard quartz more accurate.

[0042] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0043] Reference Figures 1-4 This embodiment provides a method for preparing a standard quartz sample for calibration of an stimulated luminescence dating instrument, including the following steps:

[0044] Step 1, Preparation of Loading Device 1: Prepare a quartz glass front wall and a quartz glass back wall. Both the front and back walls are flat and used to sandwich the granular quartz sample in the middle. The front wall is closer to the radiation source than the back wall. Prepare an annular pad. The annular pad is flat and used to be placed between the front and back walls of the quartz glass. The quartz sample is placed in the central hole of the annular pad.

[0045] Step 2, Quartz loading: Place the annular pad on the front side of the back wall of the quartz glass, place the quartz sample in the central hole of the annular pad, and place the front wall of the quartz glass on the front side of the annular pad.

[0046] Step 3, Quartz Irradiation: The loading device 1 is wrapped in aluminum foil, placed on a special support 2, and positioned at the measurement point of the reference radiation field for irradiation.

[0047] Step 4: Parameter Evaluation: Measure the air kerma rate at the measurement point;

[0048] Step 5: Calculate the conversion coefficient from air kerma to quartz absorbed dose;

[0049] Step 6: Calculate the absorbed dose of the quartz sample based on the air kerma rate, conversion coefficient, and irradiation time;

[0050] Step 7: After grouping the prepared quartz samples, use an illuminometer to measure them; use one-way ANOVA to calculate the ratio of between-group variance to within-group variance to evaluate the homogeneity of the quartz samples.

[0051] Step 8: Place the irradiated quartz sample in a shielded box (e.g., a lead container), and take it out at different times after irradiation for measurement. Use linear regression to fit the sample and calculate the slope and standard deviation of the linear fitting equation. Assess the stability of the quartz absorbed dose by the difference between the slope and 0.

[0052] The working principle of the standard quartz sample preparation method used for calibrating an stimulated luminescence dating instrument in this embodiment is as follows:

[0053] In the prior art, the loading device 1 is usually a hollow cylinder, which leads to inconsistent absorbed doses of quartz samples at different radial positions. In this embodiment, two flat pieces of quartz glass are used to sandwich the quartz sample in the middle, so that the quartz sample is distributed in a flat shape, reducing mutual shading of the quartz samples and thus improving the consistency of the absorbed dose of the quartz samples.

[0054] Quartz particles have a relatively small diameter (approximately 250 nm). Using the aforementioned flat plate distribution method, loading and unloading quartz samples through a narrow slit would be quite difficult. Therefore, this embodiment designs two layers of quartz glass plates with an annular pad in the middle. The quartz particles are laid flat in the central hole of the annular pad, and the front and back walls of the quartz glass are attached to the annular pad from both sides, facilitating the uniform spreading and removal of the granular quartz sample.

[0055] In the prior art, the material of the loading device 1 is usually soda glass, polyethylene, etc. However, in this embodiment, quartz glass with a smaller mass energy absorption coefficient difference from that of the quartz sample is used as the material of the loading device 1, which can better ensure that the flux spectrum of the radiation changes less when the radiation passes through the irradiation device and when it passes through the quartz sample, and the evaluation value is more accurate and reliable.

[0056] In existing technologies, black tape is typically used to wrap the loading device 1 to shield it from light. However, the composition of the black tape is unknown, and its effect on the absorbed dose of the quartz sample cannot be guaranteed. In this embodiment, aluminum foil is used to wrap the loading device 1 to shield it from light. Aluminum foil has a better light-shielding effect, and its composition is known, allowing for accurate assessment of its effect on the absorbed dose of the quartz sample, thus ensuring accurate quartz absorbed dose values.

[0057] With the above improvements, the preparation method of this embodiment can make the dosage of standard quartz more accurate, but there may still be some standard quartz samples whose dosage does not meet the requirements. These samples are rejected according to the corresponding standards after steps seven and eight.

[0058] As a possible example, in step one, if the radiation source is Cs-137, the thickness of the front wall of the quartz glass is at least 0.55 mm; if the radiation source is Co-60, the thickness of the front wall of the quartz glass is at least 2 mm, and the thickness of the back wall of the quartz glass is at least 0.5 mm.

[0059] It should be noted that the function of the front wall of the quartz glass is to ensure that the quartz sample is irradiated in a state of charged particle equilibrium. The function of the back wall of the quartz glass is to ensure that scattered particles from the back region can be compensated when the quartz sample is irradiated. Calculations show that if the radiation source is Cs-137 (energy 662 keV), the thickness of the front wall of the quartz glass should be at least 0.55 mm. Experimental results are shown in […]. Figure 3 If the radiation source is Co-60 (energy 1.25 MeV), then the thickness of the front wall of the quartz glass should be at least 2 mm, and the thickness of the back wall should be at least 0.5 mm. Experimental results are shown below. Figure 4 .

[0060] Figure 3The diagram shows the relationship between the depth of the quartz particles (depth refers to the distance from the rear surface of the front wall of the quartz glass) and the unit fluence dose under Cs-137 irradiation conditions. It can be seen that at a depth of 0.55 mm, the absorbed dose per unit fluence equals the kerma per unit fluence, indicating that charged particle equilibrium has been reached.

[0061] Figure 4 The figure shows the relationship between the depth of quartz particles and the unit fluence dose under Co-60 irradiation conditions. It can be seen that at a depth of 2 mm, the absorbed dose per unit fluence is equal to the kerma per unit fluence, indicating that charged particle equilibrium has been reached.

[0062] As a possible example, the thickness of the annular pad is no greater than 1 mm, so that the loading thickness of the quartz sample does not exceed 1 mm. For example, the thickness of the annular pad is preferably 1 mm.

[0063] As one possible example, the center hole of the annular pad can be either square or round.

[0064] For example, the outer contour dimensions of the quartz glass front wall, the quartz glass back wall, and the annular pad are the same, and the distance between the inner contour and the outer contour of the annular pad is 1 cm.

[0065] As one possible example, the lower end of the loading device 1 is fixed to the special bracket 2 or the upper end is suspended from the special bracket 2.

[0066] In existing technologies, the loading device 1 is typically fixed to plexiglass, and the backscattering of the plexiglass must be considered when calculating the quartz absorbed dose. This embodiment, by fixing the lower end or suspending the upper end, allows the quartz sample and loading device 1 to be placed naked in the radiation field for irradiation, ensuring that the quartz sample is not affected by backscattering, thus making the measurement results more accurate and reliable.

[0067] Reference Figure 2 When using the top-mounting method, the dedicated support 2 includes a pair of parallel first vertical plates 21, a pair of parallel second vertical plates 22, and a third vertical plate 23. The upper end of the first vertical plate 21 has a first upper slot, and the lower end of the first vertical plate 21 has two first lower slots. The upper end of the second vertical plate 22 has two second upper slots. The first vertical plates 21 and 22 are perpendicular to each other. The two first lower slots of the first vertical plate 21 are respectively inserted into the two second upper slots of the two second vertical plates 22. Both ends of the third vertical plate 23 are respectively inserted into the two first upper slots of the first vertical plates 21. The upper end of the loading device 1 is connected to the third vertical plate 23 via a suspension line 3 to suspend the upper end of the loading device 1 onto the dedicated support 2.

[0068] When the lower end is fixed, the dedicated bracket 2 includes a pair of parallel first vertical plates 21 and a pair of parallel second vertical plates 22. The upper end of the first vertical plate 21 has a first upper slot, and the lower end of the first vertical plate 21 has two first lower slots. The upper end of the second vertical plate 22 has two second upper slots. The first vertical plates 21 and the second vertical plates 22 are perpendicular to each other. The two first lower slots of the first vertical plate 21 are respectively inserted into the two second upper slots of the two second vertical plates 22, and the lower end of the loading device 1 is inserted into the first upper slot to fix the lower end of the loading device 1 to the dedicated bracket 2.

[0069] The dedicated bracket 2 with the above-mentioned insert structure is easy to disassemble when not in use, thereby reducing storage space.

[0070] For example, the sum of the depths of the first lower slot and the second upper slot is equal to the height of the second vertical plate 22, so that the lower end of the first vertical plate 21 is flush with the lower end of the second vertical plate 22, thereby improving the stability of the special bracket 2.

[0071] For example, the number of second upper slots at the upper end of the second vertical plate 22 is greater than two, so as to adjust the position of the first vertical plate 21.

[0072] In step five, there are multiple ways to calculate the conversion coefficients, and those skilled in the art can choose flexibly.

[0073] For example, when calculating the conversion coefficient, a corresponding model can be built using Monte Carlo software. A standard quartz integration region or detector can be placed in the corresponding area to simulate the conversion coefficient from air kerma to absorbed dose under monoenergetic photons. Then, the energy spectrum of the irradiated radiation quality is integrated with the fluence spectrum and the conversion coefficient of monoenergetic photons to obtain the average energy spectrum value of the conversion coefficient.

[0074] For example, when calculating the conversion coefficient, a corresponding model can be established using Monte Carlo software. The actual energy spectrum data at the radiation field measurement point can be input, and the air kerma and the absorbed dose of quartz can be calculated respectively to directly obtain the conversion coefficient from air kerma to absorbed dose under radiation quality.

[0075] As a possible example, in step seven, the quartz sample is divided into different samples. A portion of each sample is taken and placed on aluminum disks in 10 luminescence dating instruments for measurement. A one-way ANOVA method is used to determine whether there is systematic bias between the measurements by comparing the between-group variance and the within-group variance. If the ratio of the between-group variance to the within-group variance (F-value) is less than the critical value of the statistical test, the quartz sample is considered homogeneous. This critical value can be flexibly set by the preparation personnel according to the preparation standards.

[0076] Understandably, when performing the one-way ANOVA method in step seven, the above parameters can be adjusted to meet actual needs.

[0077] As a possible example, in step eight, after irradiating the quartz sample, a portion is randomly selected and immediately analyzed using an stimulated luminescence (SLU) analyzer. The remaining sample is placed in a shielded box for one month, and then a second portion of the quartz sample is taken out. The time interval between two consecutive quartz sample extractions is no less than one month.

[0078] For example, in step eight, the quartz sample can be taken out in 13 separate steps, at the time when the quartz sample is first placed in the shielded box, at one month, at two months, at three months, at four months, and at twelve months.

[0079] As a possible example, the absorbed dose of the quartz sample is not limited to the 5 Gy mentioned in the scheme, but can actually be wider and selected according to needs and actual conditions; the type of radiation can be X-rays, gamma rays, or beta rays, or other ray particles such as electrons; it is not limited to 662 keV (Cs-137) and 1.25 MeV (Co-60), but can be selected according to needs and actual conditions.

[0080] As a possible example, in step four, in a standard ionization chamber traced back to the γ-ray air kerma reference (such as National Basic Certificate

[2019] No. 145), the air kerma rate at the location intended to be used to irradiate quartz in the reference radiation field is accurately measured.

[0081] As a possible example, the calculation formula for step six is ​​as follows:

[0082]

[0083] in The reference radiation field measured in the standard ionization chamber is intended to be used to irradiate the air kerma at the location where the quartz is irradiated; The calibration factor for ionization chamber traceability to the reference; The ionization current in the ionization chamber; Correction for ambient air temperature and pressure; h K,D The conversion coefficient from air kerma to standard quartz absorbed dose; t This refers to the irradiation time.

[0084] The calculation formula for step eight is as follows:

[0085]

[0086]

[0087]

[0088] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A method for preparing a standard quartz sample for calibration of an stimulated luminescence dating instrument, characterized in that, Includes the following steps: Step 1: Preparation of the loading device: Prepare a quartz glass front wall and a quartz glass back wall. Both the front and back walls are flat and used to sandwich the granular quartz sample in the middle. The front wall is closer to the radiation source than the back wall. Prepare an annular pad, which is placed between the front and back walls. The quartz sample is placed in the central hole of the annular pad. Step 2, Quartz loading: Place the annular pad on the front side of the back wall of the quartz glass, place the quartz sample in the central hole of the annular pad, and place the front wall of the quartz glass on the front side of the annular pad. Step 3, Quartz Irradiation: The loading device is wrapped in aluminum foil, placed on a special support, and positioned at the measurement point of the reference radiation field for irradiation. Step 4: Parameter Evaluation: Measure the air kerma rate at the measurement point; Step 5: Calculate the conversion coefficient from air kerma to quartz absorbed dose; Step 6: Calculate the absorbed dose of the quartz sample based on the air kerma rate, conversion coefficient, and irradiation time; Step 7: After grouping the prepared quartz samples, use an illuminometer to measure them; use one-way ANOVA to calculate the ratio of between-group variance to within-group variance to evaluate the homogeneity of the quartz samples. Step 8: Place the irradiated quartz sample in a shielded box, remove it at different times after irradiation, and perform measurements. Use linear regression to fit the sample, calculate the slope and standard deviation of the linear fitting equation, and evaluate the stability of the quartz absorbed dose by the difference between the slope and 0.

2. The method for preparing standard quartz samples for calibrating an stimulated luminescence dating instrument according to claim 1, characterized in that: In step one, if the radiation source is Cs-137 with an energy of 662 keV, the thickness of the front wall of the quartz glass is at least 0.55 mm; if the radiation source is Co-60 with an energy of 1.25 MeV, the thickness of the front wall of the quartz glass is at least 2 mm, and the thickness of the back wall of the quartz glass is at least 0.5 mm.

3. The method for preparing standard quartz samples for calibrating an stimulated luminescence dating instrument according to claim 1, characterized in that: The thickness of the annular pad should not exceed 1 mm so that the loading thickness of the quartz sample does not exceed 1 mm.

4. The method for preparing a standard quartz sample for calibrating an stimulated luminescence dating instrument according to claim 1, characterized in that: The center hole of the annular pad is either round or square.

5. The method for preparing a standard quartz sample for calibrating an stimulated luminescence dating instrument according to claim 1, characterized in that: The lower end of the loading device is fixed to a special bracket or the upper end is hoisted onto a special bracket.

6. The method for preparing a standard quartz sample for calibrating an stimulated luminescence dating instrument according to claim 5, characterized in that: The special bracket includes a pair of parallel first vertical plates and a pair of parallel second vertical plates; the upper end of the first vertical plate is provided with a first upper slot, and the lower end of the first vertical plate is provided with two first lower slots; the upper end of the second vertical plate is provided with two second upper slots; the first vertical plate and the second vertical plate are perpendicular to each other; the two first lower slots of the first vertical plate are respectively inserted into the two second upper slots of the two second vertical plates, and the lower end of the loading device is inserted into the first upper slot to fix the lower end of the loading device to the special bracket.

7. The method for preparing a standard quartz sample for calibrating an stimulated luminescence dating instrument according to claim 5, characterized in that: The special support includes a pair of parallel first vertical plates, a pair of parallel second vertical plates, and a third vertical plate; the upper end of the first vertical plate is provided with a first upper slot, and the lower end of the first vertical plate is provided with two first lower slots; the upper end of the second vertical plate is provided with two second upper slots; the first vertical plate and the second vertical plate are perpendicular to each other; the two first lower slots of the first vertical plate are respectively inserted into the second upper slots of the two second vertical plates; the two ends of the third vertical plate are respectively inserted into the first upper slots of the two first vertical plates; the upper end of the loading device is connected to the third vertical plate through a suspension line to suspend the upper end of the loading device on the special support.

8. The method for preparing a standard quartz sample for calibrating an stimulated luminescence dating instrument according to claim 1, characterized in that: In step five, a corresponding model is established using Monte Carlo software. A standard quartz integration region or detector is placed in the corresponding area to simulate the conversion coefficient of air kerma under monoenergetic photons to absorbed dose. Then, the energy spectrum of the irradiated radiation is integrated with the fluence spectrum and the conversion coefficient of monoenergetic photons to obtain the average energy spectrum value of the conversion coefficient.

9. The method for preparing a standard quartz sample for calibrating an stimulated luminescence dating instrument according to claim 1, characterized in that: In step five, the corresponding model is established using Monte Carlo software. The actual energy spectrum data at the radiation field measurement point is input, and the air kerma and the absorbed dose of quartz are calculated respectively. The conversion coefficient from air kerma to absorbed dose under radiation quality is obtained directly.

10. The method for preparing a standard quartz sample for calibrating an stimulated luminescence dating instrument according to claim 1, characterized in that: In step seven, the irradiated quartz samples are divided into different samples; a portion is taken from each sample and placed on aluminum disks in 10 luminescent dating instruments for measurement; a one-way ANOVA method is used to determine whether there is systematic bias between the measurements by comparing the between-group variance and the within-group variance. If the ratio of the between-group variance to the within-group variance is less than the critical value of the statistical test, the quartz sample is considered to be homogeneous.

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