System and method for measuring moisture in soil using neutron sensors

Abstract

Systems and methods for measuring soil moisture are provided. The system may include a neutron sensor configured to be disposed at a sampling location and including one or more neutron detectors configured to detect fast neutrons and thermal neutrons at the sampling location, and a computing device including at least one data processor and a memory storing instructions, the instructions are configured to cause the processor to perform operations including receiving a first electrical signal characterizing a fast neutron count at a sampling location and a second electrical signal characterizing a thermal neutron count at the sampling location from the neutron sensor, determining a ratio of fast neutrons to thermal neutrons present at the sampling location, a soil moisture measurement is determined based on the ratio, and the soil moisture measurement is provided.

Description

[0001] Related applications

[0002] This application is based on 35 USC 119(e) claims priority to U.S. Provisional Application No. 63 / 457,913, filed April 7, 2023, the entire contents of which are expressly incorporated herein by reference. Technical Field

[0003] The topics disclosed in this article relate to systems and methods for detecting moisture in soil. Background Technology

[0004] Sensors, such as cosmic ray neutron sensors (CRNS), can be used to measure soil moisture. Current CRNS designs are limited in their ability to accurately measure soil moisture over large plots in real time without additional inference to correct or process the sensor data. As a result, soil moisture measurements may be inaccurate, and additional time and processing may be required to correct for these inaccuracies. Summary of the Invention

[0005] In one aspect, a system for measuring moisture in soil is provided. In some aspects, the system may include a neutron sensor arranged at a sampling location and including one or more neutron detectors arranged to detect fast neutrons and thermal neutrons at the sampling location. The system may also include a computing device communicatively coupled to the neutron sensor and including at least one data processor and a memory storing computer-readable instructions that, when executed by the at least one data processor, cause the processor to perform operations. In some aspects, the operations performed by the processor may include receiving from the neutron sensor a first electrical signal characterizing a fast neutron count at the sampling location and a second electrical signal characterizing a thermal neutron count at the sampling location, determining a ratio of fast neutrons to thermal neutrons present at the sampling location, determining a soil moisture measurement based on the ratio, and providing the soil moisture measurement.

[0006] In some respects, one or more neutron detectors may be selected from any of the following: helium-3 detector, helium-4 detector, lithium-6 foil detector, lithium-glass detector, boron-10 detector, and boron trifluoride detector.

[0007] In some aspects, the one or more neutron detectors further include one or more first neutron detectors arranged to detect fast neutrons and one or more second neutron detectors arranged to detect thermal neutrons. In some aspects, the one or more first neutron detectors and the one or more second neutron detectors may be helium-3 detectors. In some aspects, the one or more first neutron detectors may be encapsulated or coated in a moderator material and a shielding material, and the one or more second neutron detectors may be encapsulated or coated in at least a moderator material.

[0008] In some aspects, one or more first neutron detectors may be arranged at a first location within the sampling location, and one or more second neutron detectors may include multiple second neutron detectors arranged at multiple second locations within the sampling location. In this case, the operations performed by the processor may further include: receiving a first electrical signal from one or more first neutron detectors; receiving multiple second electrical signals characterizing multiple counts of thermal neutrons at multiple second locations within the sampling location from multiple second neutron detectors; determining multiple ratios of fast neutrons to thermal neutrons present at multiple second locations within the sampling location; determining one or more soil moisture measurements at the sampling location based on the multiple ratios; and providing one or more soil moisture measurements at the sampling location.

[0009] In some aspects, the system may also include at least one voltage source coupled to a neutron sensor at a first end and arranged to provide a predetermined voltage to the neutron sensor; and at least one ground coupled to the neutron sensor and arranged to discharge the accumulated charge in one or more neutron detectors to the ground source.

[0010] In some aspects, the system may also include at least one amplifier communicatively coupled to the neutron sensor and arranged to amplify the first and second electrical signals and transmit them to a computing device.

[0011] In some aspects, the operation performed by at least one processor may further include receiving one or more calibration constants from a memory, said calibration constants being arranged to calibrate fast neutron counts and thermal neutron counts based on multiple environmental conditions present at the sampling location, and determining soil moisture measurements based on the ratio and the one or more calibration constants. In some aspects, the multiple environmental conditions include one or more of atmospheric humidity, atmospheric pressure, biomass measurements, precipitation, altitude, latitude, topographic classification, soil bulk density, and lattice water measurements.

[0012] In some aspects, the system may also include one or more wireless transceivers communicatively coupled to one or more neutron sensors and arranged to wirelessly transmit a first electrical signal and a second electrical signal to a computing device.

[0013] In some respects, the computing device can be a mobile computing device selected from smartphones, tablets, and handheld computing devices.

[0014] On another front, a method for measuring moisture in soil is provided. In some aspects, the method may include: providing a neutron sensor at a sampling location, the neutron sensor including one or more neutron detectors arranged to detect fast neutrons and thermal neutrons at the sampling location; receiving from the neutron sensor a first electrical signal characterizing the fast neutron count and a second electrical signal characterizing the thermal neutron count at the sampling location by at least one data processor of a computing device; determining by the at least one data processor the ratio of fast neutrons to thermal neutrons present at the sampling location; determining a soil moisture measurement value by the at least one data processor based on the ratio; and providing the soil moisture measurement value to a user interface display of the computing device.

[0015] In some aspects, one or more neutron detectors may be selected from any one of helium-3 detectors, helium-4 detectors, lithium-6 foil detectors, lithium-glass detectors, boron-10 detectors, and boron trifluoride detectors. In some aspects, one or more neutron detectors may include one or more first neutron detectors arranged to detect fast neutrons and one or more second neutron detectors arranged to detect thermal neutrons.

[0016] In some aspects, one or more first neutron detectors may be arranged at a first location within the sampling location, and one or more second neutron detectors may include multiple second neutron detectors arranged at multiple second locations within the sampling location. In this case, the method may further include: receiving a first electrical signal from one or more first neutron detectors by at least one data processor; receiving multiple second electrical signals characterizing multiple counts of thermal neutrons at multiple second locations within the sampling location by at least one data processor; determining multiple ratios of fast neutrons to thermal neutrons by at least one data processor based on the first electrical signal and the multiple second electrical signals; determining one or more soil moisture measurements at the sampling location based on the multiple ratios; and providing one or more soil moisture measurements at the sampling location to a user interface display.

[0017] In some aspects, the method may further include receiving one or more calibration constants from the memory of a computing device by at least one data processor, the one or more calibration constants being arranged to calibrate fast neutron counts and thermal neutron counts based on multiple environmental conditions present at the sampling location, and determining soil moisture measurements by at least one data processor based on the ratio and the one or more calibration constants. In some aspects, the multiple environmental conditions include one or more of atmospheric humidity, atmospheric pressure, biomass measurements, precipitation, altitude, latitude, topographic classification, soil bulk density, and lattice water measurements.

[0018] In some aspects, the method may also include wirelessly transmitting a first electrical signal and a second electrical signal from the neutron sensor to a computing device via a wireless communication transceiver communicatively coupled to the neutron sensor.

[0019] In some aspects, the method may further include providing a predetermined voltage to the neutron sensor via a voltage source coupled to the neutron sensor; discharging the accumulated charge in one or more neutron detectors to the ground source via at least one ground coupled to the neutron sensor; and transmitting a first electrical signal and a second electrical signal to the computing device via at least one amplifier coupled to the neutron sensor in a communicative manner. Attached Figure Description

[0020] These and other features will be more readily understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0021] Figure 1 This is a schematic diagram illustrating a system for measuring moisture in soil according to the subject matter provided herein;

[0022] Figure 2 This is a schematic diagram illustrating another system for measuring soil moisture according to the subject matter provided herein; and

[0023] Figure 3 This is a flowchart illustrating an exemplary method for measuring soil moisture using the system described herein.

[0024] It should be noted that the accompanying drawings are not necessarily drawn to scale. The drawings are intended only to depict typical aspects of the subject matter disclosed herein and should not be considered as limiting the scope of this disclosure. Detailed Implementation

[0025] Traditionally, neutron sensors are used to measure thermal neutrons at a sampling location. Thermal neutrons are produced when fast neutrons (high-kinetic-energy neutrons typically generated during cosmic radiation and nuclear fission, when cosmic rays interact with the Earth's atmosphere) collide with atoms or atomic nuclei in a medium (e.g., soil), causing them to lose kinetic energy through elastic scattering interactions. Therefore, the kinetic energy of a thermal neutron is comparable to the thermal energy of the surrounding atoms or molecules within the medium (ranging from approximately millielectron volts (mEV) to several kiloelectron volts (keV), depending on the temperature of the surrounding medium). When a thermal neutron is absorbed by a hydrogen nucleus (proton), it produces recoil protons and gamma rays. Gamma rays can be detected using a scintillation detector, while recoil protons can be detected using a gas-filled proportional counter. Therefore, the local soil moisture content can be estimated by measuring the rates of protons and gamma rays produced by the presence of thermal neutrons. However, simply measuring thermal neutrons in the soil is insufficient for accurately measuring soil moisture over larger plots because these measurements are sensitive to the soil moisture content at the local level of the moisture sensor and cannot measure variations in factors such as solar radiation and how it affects the moisture content of larger plots near the sensor. Traditionally, this problem has been addressed by correcting local measurements using correction factors derived from sample data from databases (e.g., the International Neutron Monitor Database), where users can make inferences about environmental conditions at the sampling location (e.g., measurements of solar activity, atmospheric pressure, water vapor in the air, humidity, etc.). However, this traditional inference method can lead to errors in soil moisture measurements because it ignores the actual and dynamic environmental conditions at the sampling location.

[0026] The systems and methods described herein address the aforementioned drawbacks by providing one or more custom-designed neutron sensors configured to measure both thermal neutron flux and fast neutron flux at a sampling location. As mentioned above, fast neutrons are high-kinetic-energy neutrons typically produced during cosmic radiation and nuclear fission when cosmic rays interact with the Earth's atmosphere. Therefore, by measuring the fast neutron flux at the sampling location, the systems and methods described herein can measure factors such as variations in solar activity that affect soil moisture and are neglected by conventional methods. When fast neutrons interact with atomic nuclei (e.g., hydrogen) in the soil, they can produce numerous secondary neutrons, the number of which depends on the hydrogen content of the soil. By directly measuring fast and thermal neutrons, the systems and methods described herein can accurately measure soil moisture content by comparing and determining the ratio between the fast and thermal neutron fluxes at the sampling location, without having to infer local fast neutron fluxes based on sample data from a database as described above.

[0027] Advantageously, compared to existing neutron sensor systems, the systems and methods described herein can generate more accurate soil moisture measurements by using both fast and thermal neutrons to measure soil moisture content. Compared to existing neutron sensor systems, the systems and methods described herein can generate more accurate soil moisture measurements over a larger area (e.g., approximately 300 meters around the sensing area) with reduced processing time, additional data sources, and computing power. The systems described herein can be deployed in remote areas with limited water resources to provide efficient and accurate soil moisture measurements for agricultural, environmental, or conservation purposes. By providing accurate soil moisture readings, the systems and methods described herein allow users (e.g., farmers) to optimize resources used for agriculture. For example, in arid areas where drought frequently occurs, leading to higher water prices and making crop yields more difficult, the systems and methods described herein allow users to accurately understand soil moisture levels over a wide range of their land to better inform their decisions on when to irrigate crops to avoid crop losses due to over- or under-irrigation.

[0028] This document discusses the use of embodiments of the sensor and operating method in agricultural environments. However, embodiments of this disclosure can be used to sense moisture in any application or environment without limitation.

[0029] Figure 1 This is a diagram illustrating an embodiment of a system 100 comprising one or more neutron sensors 105 according to the subject matter provided herein, the neutron sensors being configured to determine the moisture content in soil 155 at a sampling location. Figure 1 As shown, the neutron sensor 105 may include one or more neutron detectors 110, 115, which are configured to detect fast neutrons and thermal neutrons in a sampling location / region. In some aspects, such as Figure 1As shown, the neutron sensor 105 can be positioned above the soil 155 during sampling, for example, by placing it directly on the soil or mounting it to a tripod, stake, pole, etc., placed on or inserted into the soil. Additionally, in some aspects, one or more neutron detectors 110, 115 of the neutron sensor 105 can be positioned at different locations on the sampling site / area, as discussed in more detail below. When fast neutrons penetrate the soil 155 and interact with soil particles, water molecules, and other atomic nuclei within the soil 155, the flux of fast neutrons detected by one or more neutron detectors 110, 115 is affected by the scattering and deceleration processes that occur during the interaction between the neutrons and the soil. For example, an increase in collisions with hydrogen atoms in soil water molecules leads to a decrease in the detected fast neutron flux, while a decrease in soil moisture leads to an increase in the detected flux; therefore, higher soil moisture content enhances the deceleration and scattering of fast neutrons. By monitoring the change in fast neutron flux over time, changes in soil moisture content can be determined. On the other hand, thermal neutrons are generated by the deceleration of fast neutrons and reach thermal equilibrium with the surrounding environment. The thermal neutron flux can also be detected by one or more neutron detectors 110, 115, and can provide additional information about soil moisture content. For example, higher soil moisture enhances the thermalization of neutrons, leading to a decrease in detected flux, while a decrease in soil moisture leads to an increase in detected flux.

[0030] For example, in some aspects, neutron sensor 105 may include a single neutron detector 110 or 115 configured to measure both fast neutrons and thermal neutrons; however, in other aspects, neutron sensor 105 may include a first neutron detector 110 configured to detect fast neutrons and a second neutron detector 115 configured to detect thermal neutrons, as described in more detail below. In some aspects, one or more neutron detectors 110, 115 may be selected from any of a helium-filled proportional counter (3He proportional counter), a helium-4 detector (4He recoil detector), a lithium-6 foil neutron detector, a lithium-glass detector, a boron-10 proportional counter, and a boron trifluoride (BF3) sensor. In some aspects, one or more neutron detectors 110, 115 may include a moderator material that reduces neutron energy by scattering neutrons and a shielding material that enhances absorption and prevents further scattering. Thus, the use of moderators and shielding materials can enhance the detector's sensitivity to both thermal and fast neutrons. For example, in some aspects, a first neutron detector 110 configured to detect fast neutrons may be encapsulated or coated in a first material 110a or a combination of a first material comprising a moderator material (e.g., high-density polyethylene) and a shielding material (e.g., cadmium). In some aspects, a second neutron detector 115 configured to detect thermal neutrons may be encapsulated or coated in a second material 115a or a combination of second materials. For example, the second material 115a may comprise a moderator material (e.g., high-density polyethylene). It should be noted that in some aspects, the first neutron detector 110 and / or the second neutron detector 115 may be bare (not respectively coated or encapsulated in materials 110a, 110b).

[0031] like Figure 1 As further shown, in some aspects, each neutron detector may be coupled to a high-voltage source 120, a ground 125, and one or more preamplifiers 130. Electrical signals generated by the first neutron detector 110 and the second neutron detector 115, respectively, may be provided to amplifier 135 and to computing device 140 via preamplifier 130. In some embodiments, computing device 140 may include one or more processors 145 and a memory 150 storing data and computer-readable instructions, which, when executed by at least one data processor, cause the processor to perform operations described in more detail below. Computing device 140 may be configured to determine soil moisture measurements based on electrical signals output by neutron sensor 105. In some aspects, system 100 may further include an additional data recording system (not shown) communicatively coupled to computing device 140 and configured to store data received from one or more neutron sensors 105.

[0032] Figure 2This is a schematic diagram illustrating an embodiment of a system 200 including another neutron sensor 205 according to the subject matter provided herein, the neutron sensor being configured to determine the moisture content in soil 255 at a sampling location. Figure 2 The system 200 shown includes and Figure 1 The system 100 has similar components and performs similar functions, unless otherwise stated. Figure 2 As shown, the neutron sensor 205 may include a first neutron detector 210, which includes a plurality of first neutron detectors 210a, 210b, configured to detect fast neutrons 260a, 260b at a sampling location or over a larger sampling area including the sampling location. In some aspects, by having a plurality of first neutron detectors 210a, 210b, one or more of the plurality of first neutron detectors 210a, 210b may be positioned to detect fast neutrons 260a directly incident from the atmosphere, and one or more of the plurality of first neutron detectors 210a, 210b may be positioned to detect fast neutrons 260b deflected from material (e.g., the ground) without losing a large amount of energy. System 200 may also include one or more second neutron detectors 215 configured to detect thermal neutrons 260c produced by collisions with higher-energy neutrons (e.g., fast neutrons) or atomic nuclei in the atmosphere and / or soil, causing them to lose kinetic energy. Although Figure 2 System 200 is shown with only a single second neutron detector 215; however, it should be noted that system 200 may include multiple second neutron detectors 215 configured to detect thermal neutrons 260c throughout the sampling location / area to improve system sensitivity and / or increase the range and accuracy of the resulting soil moisture measurements. For example, similar to those referenced above... Figure 1 In some aspects, sensor 205 may include a single first neutron detector 210a, 210b or multiple first neutron detectors 210a, 210b disposed at a location within a larger sampling area and configured to detect fast neutrons 260a, 260b within the sampling area, and multiple second neutron detectors 215 disposed in a distributed manner at multiple sampling locations within the larger sampling area and configured to detect thermal neutrons 260c at the multiple sampling locations. In this case, system 200 may use a first electrical signal representing the count of fast neutrons 260a, 260b from the first neutron detectors 210a, 210b characterizing the sampling area, and a second electrical signal representing the count of thermal neutrons at the sampling locations from the multiple distributed second neutron detectors 215 to determine multiple ratios of fast neutron counts to multiple thermal neutron counts, and determine one or more soil moisture measurements based on the multiple ratios.

[0033] In some respects, a plurality of first neutron detectors 210a, 210 and one or more second neutron detectors 215 may be selected from the above references. Figure 1 Any of the detector types described. In some aspects, each neutron detector 210a, 210b of the first neutron detector 210 may be coupled to a high-voltage source 220a, 220b and a ground 225a, respectively. In some embodiments, the high-voltage sources 220a, 220b may be the same voltage source. In some embodiments, the second neutron detector 215 may also be coupled to a high-voltage source 220c. The second neutron detector 215 may also be coupled to a ground 225b. In some embodiments, grounds 225a and 225b may be the same ground. In some aspects, the electrical signals provided by the pair 210a, 210b of the first neutron detector 210 and the second neutron detector 220 may be provided to an amplifier 235 and to a computing device 240. In some embodiments, the computing device 240 may include at least one processor 245 and a memory 250, similar to those described above. The computing device 240 may be configured to determine soil moisture measurements based on the electrical signals output by the neutron sensor 205, as described in more detail below.

[0034] In some embodiments, neutron sensors 105 or 205 may be configured in a network of sensors. In this network, multiple neutron sensors 105 and / or 205 can be distributed across the measurement or sampling area and communicatively coupled to an amplifier and a computing device. In some embodiments, neutron sensors 105 and / or 205 may include wireless communication transceivers configured to communicate wirelessly with the computing device. In some embodiments, system 100 and / or 200 may include a mobile computing platform. For example, the computing device may be a mobile computing device, such as a smartphone, tablet, or handheld computing device, configured to receive electrical signals from neutron sensors 105 and / or 205. By providing multiple neutron sensors 105 and / or 205 across the measurement or sampling area, the system can acquire multiple fast neutron and thermal neutron measurements at multiple locations. Using multiple fast neutron and thermal neutron measurements, the system can determine multiple ratios of fast neutrons to thermal neutrons present at multiple locations, and based on these ratios, determine soil moisture measurements at each of the multiple locations, as well as the soil moisture measurement for the entire sampling area. In some aspects, the soil moisture measurement for the entire sampling area can be determined by averaging the soil moisture measurements at each location. For example, in some aspects, the soil moisture measurement for the entire sampling area can be determined by performing a weighted average or a density-based weighted average.

[0035] Figure 3 It shows the use Figure 1A flowchart of an embodiment of a method 300 for systematically measuring soil moisture according to the subject matter provided herein. Method 300 may include step 310 of providing a neutron sensor at a sampling location, the neutron sensor comprising one or more neutron detectors configured to detect fast neutrons and thermal neutrons at the sampling location. In some aspects, the neutron sensor may be similar to that described above. Figure 1 and Figure 2 The neutron sensor described is 105 or 205. Therefore, in some aspects, the neutron sensor may include a single neutron detector configured to measure both fast neutrons and thermal neutrons. In some aspects, the neutron sensor may include one or more first neutron detectors configured to detect fast neutrons and one or more second neutron detectors configured to detect thermal neutrons. In some aspects, the neutron sensor may be positioned above the soil at the sampling location, for example, by placing it directly on the soil or mounting it to a tripod, stake, pole, etc., placed on or inserted into the soil. The neutron sensor may be configured to acquire neutron flux measurements from one or more neutron detectors and generate a first electrical signal characterizing the fast neutron count from the atmosphere at the sampling location and a second electrical signal characterizing the thermal neutron count in the soil at the sampling location.

[0036] Method 300 may further include step 320, in which at least one data processor of a computing device receives from the neutron sensor a first electrical signal characterizing a fast neutron count at the sampling location and a second electrical signal characterizing a thermal neutron count at the sampling location. In some aspects, the first and second electrical signals may be wirelessly transmitted from the neutron sensor to the computing device via a wireless communication transceiver communicatively coupled to the neutron sensor. In some aspects, the neutron sensor may further include at least one amplifier communicatively coupled to the neutron sensor and configured to amplify the first and second electrical signals when they are transmitted to the computing device.

[0037] In some aspects, step 320 may further include receiving one or more calibration constants by at least one processor, which are configured to calibrate the fast neutron count and thermal neutron count based on multiple environmental conditions present at the sampling location. As described above, there is an analytical relationship between thermal neutron flux, fast neutron flux, and the amount of moisture in the soil surrounding the sensor. In some aspects, the ratio of thermal neutrons to fast neutrons may be linearly correlated with moisture or correlated via a higher-order function. Therefore, in some aspects, the method may further include an initial step of calibrating one or more parameters or aspects of the neutron sensor or system 100. Calibrating one or more parameters or aspects of system 100 may include collecting data from the sensors described herein (e.g., neutron sensors 105, 205) and / or via other data collection means under a representative set of environmental conditions at the sampling location, and determining the relationship between thermal neutron flux, fast neutron flux, and the amount of moisture in the soil surrounding the sensor, as well as determining any proportionality constants or higher-order terms that may be required for calibration. For example, in some aspects, the initial calibration steps to determine any proportionality constants, environmental corrections, and / or higher-order terms that may be required for calibration may include, but are not limited to, collecting data from other sensors regarding one or more of the changes in atmospheric pressure / humidity. Additionally, the initial calibration steps to determine any proportionality constants, environmental corrections, and / or higher-order terms that may be required for calibration may include, but are not limited to, collecting data regarding the presence of biomass in / above the soil, precipitation, changes in altitude / latitude / topography, changes in soil bulk density, and the presence of lattice water in the soil.

[0038] Variations in atmospheric pressure affect the frequency of collisions between fast neutrons and particles in the atmosphere, which can influence the density of fast neutrons near the soil surface, potentially affecting soil moisture measurements determined using neutron sensors as described herein. Additionally, low-neutron concentrations are measured when fast neutrons collide with low-atomic-weight atoms (e.g., hydrogen). Since water contains the majority of hydrogen in soil, variations in atmospheric humidity can affect soil moisture measurements determined using neutron sensors as described herein. Furthermore, variations in solar activity can influence temperature and precipitation patterns, which in turn affect soil moisture. Therefore, by collecting data on variations in atmospheric pressure / humidity at sampling locations, the systems and methods described herein can accurately determine the analytical relationships between these variations and fast neutron flux and thermal neutron flux, leading to a more accurate determination of soil moisture content.

[0039] Furthermore, the presence of biomass can influence soil moisture through its effect on evapotranspiration. For example, more biomass in the soil may lead to increased transpiration, which draws water from the soil. Biomass can also act as a cover, reducing evaporation from the soil surface and retaining moisture. In some respects, biomass in a soil region can be determined by physically separating and quantifying the different components of biomass within a soil sample, performing soil respiration measurements, fumigating soil samples with chloroform to lyse microbial cells and analyze the released carbon and nitrogen, although other methods can also be used to determine biomass. Precipitation directly affects moisture; higher precipitation levels generally lead to increased soil moisture, while lower precipitation levels result in drier soils. Altitude, latitude, and topography, such as temperature, precipitation patterns, and slope, further influence soil moisture. For example, higher altitudes and latitudes typically experience cooler temperatures and may receive more precipitation, resulting in higher soil moisture levels. Topography can influence runoff and drainage patterns, thus affecting soil moisture distribution. Soil bulk density (the mass of soil per unit volume) can influence soil moisture retention. Higher soil bulk density generally reduces the pore space available for water storage, leading to lower soil moisture levels and lower bulk density, thus allowing for greater water retention capacity. These variations in soil porosity can also affect soil moisture measurements determined using neutron sensors as described herein. Lattice water (water molecules bound within the lattice structure of certain minerals in the soil) is another source of hydrogen in the soil, and it is important to consider lattice water when measuring soil moisture using neutron sensors as described herein. Increased lattice water content can enhance soil moisture retention, while reduced content can lead to drier soil conditions. Therefore, by collecting data on biomass, precipitation, elevation, latitude, topography, soil bulk density, and lattice water content at the sampling location, the system and methods described herein can accurately determine the analytical relationships between these environmental factors and fast and thermal neutron fluxes to more accurately determine soil moisture content. However, it should be noted that by locally measuring the cosmic neutron flux within the soil as described above, the need for environmental correction or the overall magnitude of the correction can be reduced.

[0040] Method 300 may further include step 330, in which at least one processor determines the ratio of fast neutrons to thermal neutrons present at the sampling location based on a first electrical signal and a second electrical signal. For example, based on the first electrical signal and the second electrical signal output by the first and second neutron detectors of neutron sensor 105, computing device 140 may determine the ratio of fast neutron count to thermal neutron count, which indicates the ratio of fast neutrons to thermal neutrons present at the sampling location.

[0041] Method 300 may further include step 340, in which at least one processor determines a soil moisture measurement based on the ratio of fast neutrons to thermal neutrons present at the sampling location. In some embodiments, one or more of the aforementioned calibration constants may be used to convert the ratio to moisture content. Additional environmental corrections for variations in atmospheric pressure / humidity, the presence of biomass in / above the soil, precipitation, variations in altitude / latitude / topography, variations in soil bulk density, and the presence of lattice water in the soil may be determined based on data collected from other sensors and / or discovered experimentally or through simulation, and may also be applied as described above.

[0042] Method 300 may also include a step 350 of providing soil moisture measurements. For example, in some embodiments, computing device 140 may also include a display configured to display the soil moisture measurements. Additionally, the soil moisture measurements may be provided for storage in a memory and / or data recording system as described herein.

[0043] The improved systems and methods described in this paper address the technical challenge of accurately determining soil moisture measurements in real time without additional post-processing or computational resources. Furthermore, the methods described in this paper take into account the contributions of fast neutron rays and thermal neutron rays to soil moisture determination, which are previously unknown or unimplemented in neutron sensor systems. Additionally, the systems, sensors, and methods described in this paper enable rapid deployment of systems (e.g., systems 100, 200) for distributed monitoring applications in environments where water retention and soil management are critical, such as the determination and / or monitoring of crop irrigation schedules.

[0044] The subject matter described herein can be implemented in analog electronic circuits, digital electronic circuits and / or computer software, firmware, or hardware (including structural devices and their structural equivalents disclosed herein) or combinations thereof. The subject matter described herein can be implemented as one or more computer program products, such as one or more computer programs tangibly contained in an information carrier (e.g., contained in a machine-readable storage device) or contained in a propagating signal, for execution by or control of a data processing device (e.g., a programmable processor, a computer, or multiple computers). A computer program (also referred to as a program, software, software application, or code) can be written in any form of programming language (including compiled or interpreted languages) and can be deployed in any form, including as a standalone program or as a module, component, subroutine, or other unit suitable for a computing environment. A computer program does not necessarily correspond to a file. A program can be stored as a portion of a file containing other programs or data, in a single file dedicated to the program under consideration, or in multiple co-located files (e.g., a file storing portions of one or more modules, subroutines, or code). Computer programs can be deployed to run on one computer or on multiple computers located at one site or distributed across multiple sites and interconnected by a communication network.

[0045] The processes and logical flows described in this specification, including the method steps of the subject matter herein, can be executed by one or more programmable processors that execute one or more computer programs to perform the functions of the subject matter herein by manipulating input data and generating output. These processes and logical flows can also be executed by special-purpose logic circuitry (e.g., FPGAs (Field-Programmable Gate Arrays) or ASICs (Application-Specific Integrated Circuits)), and the apparatus of the subject matter herein can be implemented as special-purpose logic circuitry (e.g., FPGAs or ASICs).

[0046] By way of example, processors suitable for executing computer programs include both general-purpose microprocessors and special-purpose microprocessors, as well as any one or more processors in any kind of digital computer. Generally, a processor receives instructions and data from read-only memory or random access memory, or both. The basic components of a computer are a processor for executing instructions and one or more memory devices for storing instructions and data. Generally, a computer will also include one or more mass storage devices (e.g., magnetic disks, magneto-optical disks, or optical disks) for storing data, or operatively coupled to receive data from or transfer data to one or more mass storage devices. In some embodiments, the computer and / or microprocessor may be configured in cloud computing environments, containerized computing environments, distributed computing environments, etc. Information carriers suitable for containing computer program instructions and data include all forms of non-volatile memory, including, for example, semiconductor memory devices (e.g., EPROM, EEPROM, and flash memory devices); magnetic disks (e.g., internal hard disks or removable disks); magneto-optical disks; and optical disks (e.g., CDs and DVDs). The processor and memory may be supplemented by or incorporated into special-purpose logic circuitry.

[0047] To provide interaction with the user, the subject matter described herein can be implemented on a computer having a display device for displaying information to the user, such as a CRT (cathode ray tube) or LCD (liquid crystal display) monitor, and a keyboard and pointing device (e.g., a mouse or trackball) that the user can use to provide input to the computer. Other types of devices can also be used to provide interaction with the user. For example, the feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback), and the system can receive input from the user in any form, including sound, speech, or tactile input.

[0048] The techniques described herein can be implemented using one or more modules. As used herein, the term "module" refers to computing software, firmware, hardware, and / or various combinations thereof. However, at a minimum, a module should not be construed as software not implemented on hardware, firmware, or recorded on a non-transitory processor-readable and recordable storage medium (i.e., a module itself is not software). In practice, a "module" will be interpreted as always including at least some physical non-transitory hardware, such as a processor or part of a computer. Two different modules may share the same physical hardware (e.g., two different modules may use the same processor and network interface). The modules described herein can be combined, integrated, separated, and / or replicated to support a variety of applications. Additionally, instead of functions performed at a particular module, or functions described herein as performing at a particular module, functions may be performed at one or more other modules and / or by one or more other devices. Furthermore, modules can be implemented locally or remotely across multiple devices and / or other components relative to each other. Additionally, modules can be moved from one device and added to another device, and / or may be included in two devices.

[0049] The subject matter described herein can be implemented in a computing system that includes backend components (e.g., a data server), middleware components (e.g., an application server), or frontend components (e.g., a client computer with a graphical user interface or web browser through which a user can interact with embodiments of the subject matter described herein), or any combination of such backend, middleware, and frontend components. The components of the system can be interconnected via any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include local area networks (“LANs”) and wide area networks (“WANs”), such as the Internet.

[0050] Certain exemplary embodiments are described to provide a comprehensive understanding of the principles of the structure, function, manufacture, and use of the systems, devices, and methods disclosed herein. One or more examples of these embodiments are illustrated in the accompanying drawings. It will be understood by those skilled in the art that the systems, devices, and methods specifically described herein and illustrated in the accompanying drawings are non-limiting exemplary embodiments, and that the scope of the invention is defined only by the claims. Features shown or described in conjunction with one exemplary embodiment may be combined with features of other embodiments. Such modifications and variations are intended to be included within the scope of the invention. Furthermore, in this disclosure, similarly named components of embodiments generally have similar features, and therefore, within a specific embodiment, not every feature of every similarly named component is necessarily fully described.

[0051] As used herein throughout the specification and claims, approximate language may be used to modify any quantitative expression that allows for variations without causing a change in its essential function. Therefore, values ​​modified by one or more terms such as “about,” “approximately,” and “substantially” should not be limited to the specified precise value. In at least some cases, approximate language may correspond to the precision of the instrument used to measure the value. Scope limitations may be combined and / or interchanged herein and throughout the specification and claims, and unless otherwise indicated by context or language, such scopes are identified and include all subscopes contained therein.

[0052] Based on the above embodiments, those skilled in the art will understand other features and advantages of the present invention. Therefore, except as indicated in the appended claims, this application is not limited to the content specifically shown and described. All publications and references cited herein are expressly incorporated in their entirety by reference.

Claims

1. A system comprising: A neutron sensor, configured to be positioned at a sampling location and including one or more neutron detectors, the one or more neutron detectors being configured to detect fast neutrons and thermal neutrons at the sampling location; and A computing device, communicatively coupled to the neutron sensor and including at least one data processor and a memory storing computer-readable instructions, which, when executed by the at least one data processor, cause the processor to perform operations, including: The neutron sensor receives a first electrical signal characterizing the fast neutron count at the sampling location and a second electrical signal characterizing the thermal neutron count at the sampling location; Determine the ratio of fast neutrons to thermal neutrons present at the sampling location; Soil moisture measurements are determined based on the ratio; and Provide the soil moisture measurement values.

2. The system of claim 1, wherein the one or more neutron detectors are selected from any one of a helium-3 detector, a helium-4 detector, a lithium-6 foil detector, a lithium-glass detector, a boron-10 detector, and a boron trifluoride detector.

3. The system of claim 2, wherein the one or more neutron detectors further comprises: One or more first neutron detectors, the first neutron detectors being configured to detect fast neutrons; and One or more second neutron detectors, the second neutron detectors being configured to detect thermal neutrons.

4. The system of claim 3, wherein the one or more first neutron detectors and the one or more second neutron detectors are helium-3 detectors.

5. The system of claim 3, wherein the one or more first neutron detectors are encapsulated or coated in a moderator material and a shielding material, and the one or more second neutron detectors are encapsulated or coated in at least the moderator material.

6. The system of claim 3, wherein the one or more first neutron detectors are arranged at a first location within the sampling location, and the one or more second neutron detectors comprise a plurality of second neutron detectors arranged at a plurality of second locations within the sampling location, and the operation performed by the at least one processor further comprises: Receive the first electrical signal from the one or more first neutron detectors; Receive multiple second electrical signals, representing multiple counts of thermal neutrons at the multiple second locations within the sampling location, from the multiple second neutron detectors; Determine multiple ratios of fast neutrons to thermal neutrons present at the plurality of second locations within the sampling location; One or more soil moisture measurements at the sampling location are determined based on the multiple ratios; and Provide the one or more soil moisture measurements at the sampling locations.

7. The system according to claim 1, further comprising: At least one voltage source, the at least one voltage source being coupled to the neutron sensor at a first end and configured to provide a predetermined voltage to the neutron sensor; and At least one grounding point is coupled to the neutron sensor and configured to discharge the accumulated charge in the one or more neutron detectors to the grounding source.

8. The system according to claim 1, further comprising: At least one amplifier, communicatively coupled to the neutron sensor, and configured to amplify the first electrical signal and the second electrical signal and transmit the first electrical signal and the second electrical signal to the computing device.

9. The system of claim 1, wherein the operation performed by the at least one processor further comprises: One or more calibration constants are received from the memory, the one or more calibration constants being configured to calibrate the fast neutron count and the thermal neutron count based on multiple environmental conditions present at the sampling location; as well as The soil moisture measurement value is determined based on the ratio and one or more calibration constants.

10. The system according to claim 9, wherein, The multiple environmental conditions include one or more of atmospheric humidity, atmospheric pressure, biomass measurement, precipitation, altitude, latitude, topographic classification, soil bulk density, and lattice water measurement.

11. The system according to claim 1, further comprising: One or more wireless communication transceivers, the one or more wireless communication transceivers being communicatively coupled to one or more neutron sensors, and configured to wirelessly transmit the first electrical signal and the second electrical signal to the computing device.

12. The system of claim 1, wherein the computing device is a mobile computing device selected from smartphones, tablets, and handheld computing devices.

13. A method, the method comprising: A neutron sensor is provided at the sampling location, the neutron sensor comprising one or more neutron detectors configured to detect fast neutrons and thermal neutrons at the sampling location; At least one data processor of a computing device receives from the neutron sensor a first electrical signal characterizing the fast neutron count at the sampling location and a second electrical signal characterizing the thermal neutron count at the sampling location; The ratio of fast neutrons to thermal neutrons present at the sampling location is determined by the at least one data processor. The soil moisture measurement value is determined by the at least one data processor based on the ratio; as well as The soil moisture measurement value is provided to the user interface display of the computing device.

14. The method of claim 13, wherein the one or more neutron detectors are selected from any one of a helium-3 detector, a helium-4 detector, a lithium-6 foil detector, a lithium-glass detector, a boron-10 detector, and a boron trifluoride detector.

15. The method of claim 14, wherein the one or more neutron detectors comprise one or more first neutron detectors configured to detect fast neutrons and one or more second neutron detectors configured to detect thermal neutrons.

16. The method of claim 15, wherein the one or more first neutron detectors are arranged at a first location within the sampling location, and the one or more second neutron detectors comprise a plurality of second neutron detectors arranged at a plurality of second locations within the sampling location, the method further comprising: The first electrical signal is received from the one or more first neutron detectors by the at least one data processor; The at least one data processor receives from the plurality of second neutron detectors a plurality of counts of thermal neutrons at the plurality of second locations within the sampling location a plurality of second electrical signals characterizing the thermal neutrons at the plurality of second locations; The at least one data processor determines multiple ratios of fast neutrons to thermal neutrons based on the first electrical signal and the plurality of second electrical signals; One or more soil moisture measurements at the sampling location are determined based on the multiple ratios; as well as The soil moisture measurements at the sampling locations are provided to the user interface display.

17. The method of claim 13, further comprising: The at least one data processor receives one or more calibration constants from the memory of the computing device, the one or more calibration constants being configured to calibrate the fast neutron count and the thermal neutron count based on multiple environmental conditions present at the sampling location; as well as The soil moisture measurement is determined by the at least one data processor based on the ratio and the one or more calibration constants.

18. The method according to claim 17, wherein, The multiple environmental conditions include one or more of atmospheric humidity, atmospheric pressure, biomass measurement, precipitation, altitude, latitude, topographic classification, soil bulk density, and lattice water measurement.

19. The method of claim 13, further comprising: The first electrical signal and the second electrical signal are wirelessly transmitted from the neutron sensor to the computing device via a wireless communication transceiver communicatively coupled to the neutron sensor.

20. The method of claim 13, further comprising: A predetermined voltage is supplied to the neutron sensor via a voltage source coupled to the neutron sensor; The accumulated charge in the one or more neutron detectors is discharged to a ground source via at least one ground coupled to the neutron sensor; as well as The first electrical signal and the second electrical signal are transmitted to the computing device via at least one amplifier communicatively coupled to the neutron sensor.

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