Digital Neutron Dosimeter Based on 3D NOT-AND (NAND) Flash Memory

Abstract

A digital neutron and photon track dosimeter based on a three-dimensional NOT-AND (3D NAND) flash memory may be provided. A plurality of logical addresses respectively associated with a plurality of cells of a 3D NAND flash memory inverted from a first charge state to a second charge state may be determined. Next, the plurality of logical addresses may be converted by radiation into a plurality of physical addresses associated with the plurality of cells of the 3D NAND flash memory inverted from the first charge state to the second charge state. Next, a radiation dose proportional to the number of tracks of the plurality of cells associated with the plurality of physical addresses may be determined.

Description

Technical Field

[0001] This application is filed on June 21, 2023 as a PCT international patent application claiming the benefit and priority of US Provisional Application No. 63 / 354,161 filed on June 21, 2022, which is incorporated herein by reference.

[0002] The present disclosure generally relates to a digital neutron dosimeter based on a three-dimensional NOT-AND (NAND) flash memory.

Summary of the Invention

Problems to be Solved by the Invention

[0003] A radiation dosimeter is a device that measures the absorbed dose of external ionizing radiation. When used as a personal dosimeter, it is worn by the person being monitored to obtain a legal record of the radiation dose. Recent electronic personal dosimeters (EPDs) can continuously read the accumulated dose and the current dose rate, and can issue a warning to the wearer with an alarm sound when the specified dose rate or accumulated dose exceeds a preset threshold. Other dosimeters, such as those of the thermoluminescence (TL) type or optically stimulated luminescence (OSL) type, may require post-use processing to reveal the accumulated dose received and may not indicate the current dose during wear.

Means for Solving the Problems

[0004] An electronic personal dosimeter is an electronic device having a number of functions such as continuous monitoring that can issue an alarm warning at a preset level and read out the accumulated dose live. These are particularly useful in high-dose areas where the wearer's stay time is restricted by dose constraints. This dosimeter can usually be reset after obtaining a measurement for recording, and thus can be reused many times. The main drawbacks of this dosimeter are that it is always battery-dependent and there is a possibility of losing dose information when the battery runs out.

Brief Description of the Drawings

[0005] The accompanying drawings, which are incorporated in and constitute a part of this disclosure, illustrate various embodiments of the disclosure.

[0006]

Figure 1

[0007]

Figure 2

[0008]

Figure 3

[0009]

Figure 4

[0010]

Figure 5

[0011]

Figure 6

[0012]

Figure 7

[0013]

Figure 8

[0014]

Figure 9

[0015]

Figure 10

Mode for Carrying Out the Invention

[0016] Overview A digital neutron dosimeter based on a three-dimensional NOT-AND (NAND) flash memory may be provided. A digital neutron and photon track dosimeter based on a three-dimensional NOT-AND (3D NAND) flash memory may be provided. A plurality of logical addresses respectively associated with a plurality of cells of a 3D NAND flash memory inverted from a first charge state to a second charge state may be determined. Next, the plurality of logical addresses may be converted by radiation into a plurality of physical addresses associated with a plurality of cells of the 3D NAND flash memory inverted from the first charge state to the second charge state. Next, a radiation dose proportional to the number of tracks of a plurality of cells associated with the plurality of physical addresses may be determined.

[0017] Both the above-described overview and the following exemplary embodiments are merely exemplary and explanatory, and should not be considered as limiting the scope of the present disclosure as described and claimed. Further, in addition to what has been described, features and / or modifications may be provided. For example, embodiments of the present disclosure are directed to various combinations and sub-combinations of the various features described in the exemplary embodiments.

[0018] Exemplary Embodiments The following detailed description refers to the accompanying drawings. Whenever possible, the same reference numbers are used in the drawings and the following description to refer to the same or similar elements. Embodiments of the present disclosure can be described, but modifications, adaptations, and other realizations are possible. For example, substitutions, additions, or changes to the elements shown in the drawings can be made, and the methods described herein can be changed by making substitutions, changing the order, or adding steps to the disclosed methods. Accordingly, the following detailed description does not limit the present disclosure. Instead, the appropriate scope of the present disclosure is defined by the appended claims.

[0019] Embodiments of the present disclosure may provide methods and systems for use in a high-fidelity wireless digital neutron dosimeter based on a three-dimensional (3D) NAND flash memory (i.e., a 3D electron track detector (3DETD)). This may be based on the concept of a nuclear track detector when radiation forms so-called "tracks" in the three-dimensional volume of the detection medium. These "tracks" due to the radiation are identified and counted against the background of readout noise, and the number of tracks is proportional to the dose accumulated in the dosimeter.

[0020] One advantage of embodiments of the present disclosure is that it can provide for the accumulation of dose information in the capacity of the dosimeter sensor without requiring power (i.e., it can be a passive integrating sensor), while at the same time useful data readout and streaming may use power (e.g., a battery). In contrast, conventional active neutron dosimeters require power to operate.

[0021] Conventional passive nuclear track dosimeters such as plastic nuclear track detectors (PNTDs) and fluorescent nuclear track detectors (FNTDs) may have sensitivity and performance for neutron detection, but may not be processed in the field and may require processing in a laboratory with an expensive reader. Embodiments of the present disclosure may combine the fidelity of a passive integrating track detector with the ability to measure / read out the dose at required or necessary time intervals and wirelessly transmit the data to a base station and the cloud for final processing.

[0022] In contrast to conventional “active” dosimeters that detect each event of radiation interaction and always require an applied voltage, “passive” sensors may not need to stop accumulating dose information even when battery power is lost. Embodiments of the present disclosure may include utilizing existing robust 3D NAND technology in a 3D radiation track capacitance detector combined with the selection of threshold voltages optimal for reading 3D NAND chips. Further, embodiments of the present disclosure may provide the ability to identify and distinguish individual radiation-induced tracks in the background of readout noise, for example, using clustering algorithms and machine learning / deep learning tools.

[0023] Embodiments of the present disclosure may be based on a binary concept of setting to 1 when there is a track and to 0 when there is no track. As a result, the dosimeter may not be affected by manufacturing variations and fluctuations in sensor sensitivity due to external environmental factors such as temperature, humidity, battery voltage, and electromagnetic interference (EMI). This is in contrast to conventional analog sensor technologies such as metal-oxide-semiconductor field-effect transistors (MOSFETs), PIN diodes, or direct ion storage (DIS) sensors that are sensitive to many of the environmental factors described above.

[0024] Conventional track detectors may be limited to low-dose measurements because at high doses, tracks within the sensor capacitance may begin to overlap and it may become difficult to distinguish individual tracks. In embodiments of the present disclosure, high-dose radiation may be measured when the number of interactions with the sensor is very large such that individual tracks overlap within the sensor capacitance and other image processing techniques such as power spectrum integration (PSI) processing used in FNTD technology are used.

[0025] Neutron radiation has few interactions with the sensor, and the sensor has a large interaction area and capacitance to achieve the required detection lower limit (LLD). As a result, the track detector can have a better signal-to-noise ratio (SNR) than analog sensors and at the same time can have good counting statistics. Furthermore, by using commercially available components (e.g., 3D NAND chips), the cost-effectiveness of the neutron dosimeter according to embodiments of the present disclosure can be further increased.

[0026] FIG. 1 shows a two-dimensional (2D) memory structure. As shown in FIG. 1, in a 2D memory structure, there may be no way to distinguish cells affected by radiation from cells that have experienced "inversion" as a result of read noise. FIG. 2 is a diagram showing linear radiation-induced tracks in 3D NAND memory. The tracks in the 3D NAND memory may be identified from random read noise (i.e., uncorrelated individual cell inversions).

[0027] As will be described in more detail below in connection with FIG. 9, the 3D NAND flash memory 930 may comprise a triple-level cell (TLC) flash memory. The TLC flash memory may comprise a type of NAND flash memory that stores 3 bits of data per cell. The TLC memory may be programmed to eight different charge states. Prior to use, the floating gate of the memory cell may be charged to a high charge state (e.g., the first charge state). Radiation may discharge the floating gate of the memory, and at a selected threshold voltage Vth, more cells may appear in a low charge state (e.g., the second charge state). Embodiments of the present disclosure may have a selection of an optimal threshold voltage Vth (e.g., the second charge state) for an optimal number of cells to be processed and analyzed.

[0028] FIG. 3 shows a cloud of inverted cells of a selected sub-volume (e.g., 240×120×64 cells) of a 3D NAND flash memory 930 that includes both alpha particle radiation-induced inversion and read noise. FIG. 4 shows ion-induced tracks of a small sub-volume of a 3D NAND flash memory 930 (e.g., 240×120×64 cells) after being processed using clustering and shape processing algorithms, as will be described in more detail below. FIG. 5 shows a visualization of the tracks after connecting non-linear tracks belonging to the same irradiation event. It has been demonstrated that 3D NAND can also be used for the detection of gamma photons that form so-called delta electron tracks. These tracks often form a curved or spherical shape rather than a straight line of inverted cells like recoil proton tracks or alpha tracks. A deep learning approach using a trained neural network classification algorithm is utilized to distinguish neutron-induced tracks from photon-induced tracks. FIG. 6 shows a small sub-volume of the 3D NAND flash memory 930 that has not been irradiated with either neutrons or gamma photons. Only the inversion of a single cell related to the read noise after processing using clustering and shape processing algorithms is shown. FIG. 7 shows the angular tracks generated by alpha particles.

[0029] Embodiments of the present disclosure may provide a portable wireless passive integrated neutron and photon sensor and a dosimeter that can accumulate dose without requiring battery power during radiation exposure and can perform readout using battery power as needed or at predetermined time intervals. Embodiments of the present disclosure may use the 3D capacity of a NAND memory chip to identify radiation-induced tracks from random read noise by detecting radiation-induced tracks and using a density-based clustering algorithm that includes the collinearity of clusters forming the tracks and their shape parameters.

[0030] The 3D NAND flash memory for track capacity detection may be coated with a neutron converter. First, the 3D NAND flash memory cells are programmed to the most stable charge state. To obtain the optimal density of read noise and radiation-induced inversion in the 3D sub-capacity for future data processing, the most effective (i.e., optimized) threshold voltage Vth may be selected. The logical cell address (e.g., bit line, word line, block number, etc.) may be converted to the physical 3D cell coordinates. A mathematical algorithm for 3D image processing for track identification and counting may be applied. For example, wireless transmission of a limited amount of 3D cell addresses and data processing in the web cloud may be performed.

[0031] The 3D track-based method for measuring neutron dose may have many advantages compared to 2D sensors. Neutrons do not generate ionization themselves and may require a converter to generate ionizing particles. The neutron detection technology according to the embodiments of the present disclosure may be based on, for example, the identification of straight tracks generated by recoil protons resulting from the interaction of neutrons with a converter material (e.g., polyethylene containing a high concentration of hydrogen atoms (protons)). Since the mass of neutrons is approximately the same as that of protons, fast neutrons may have the largest interaction cross-section with materials containing hydrogen (protons), and neutrons may transfer up to 100% of their kinetic energy to protons and eject protons from the converter.

[0032] Recoil protons may cause ionization in the sensor material and be detected. In the case of thermal neutrons and epithermal neutrons, one way to convert neutrons into ionizing particles is 6 Li- or 10 to use B-containing materials. The reason is that both isotopes have a large capture cross-section for low-energy neutrons and may generate alpha particles and / or tritium ions as a result of nuclear reactions. In other words, regarding the converter, polyethylene, 6 Li-containing glass, 10B may use glass or plastic for detecting fast neutrons and thermal neutrons respectively, and may use hydrogen-free polytetrafluoroethylene (PTFE) plastic for identifying gamma photon events.

[0033] In a 2D detector, as shown in FIG. 1, it is difficult to distinguish in-cell events caused by charged particles from random readout noise. In contrast, the heavy charged particles or delta electrons generated by gamma photons passing through a 3D detector may generate linear or curved tracks and can be distinguished from individual cell events caused by readout noise, as shown in FIG. 2. Mathematical 3D image processing using a density-based clustering algorithm, shape parameter identification, and combination of small clusters located on the same straight line can separate radiation-induced tracks from readout noise.

[0034] FIG. 8 is a flowchart showing the general steps involved in method 800 according to an embodiment of the present disclosure for providing a digital neutron or photon dosimeter based on 3D NAND flash memory. Method 800 may be implemented using computer device 900, 3D NAND flash memory 930, and flash control device 935, as will be described in more detail below with respect to FIG. 9. The manner of implementing the steps of method 800 will be described in more detail below.

[0035] Method 800 begins at start block 805 and may proceed to step 810 where flash control device 935 may read a flash memory designated location of a flash die to determine a plurality of logical addresses each associated with a respective one of a plurality of cells of 3D NAND flash memory 930 that have been reversed from a first charge state to a second charge state. For example, 3D NAND flash memory 930 may be coated with a converter. When neutrons collide with the converter, protons may be ejected from the converter. The ejected protons pass through 3D NAND flash memory 930 and reverse the cell's track from a first charge state in which the cell was first programmed to a second charge state. The first charge state may be higher than the second charge state.

[0036] A radiation-induced event in a memory cell may be indicated by a loss of charge stored in the floating gate of a MOSFET transistor and may be identified by selecting an appropriate threshold voltage applied to the control gate during a read process of the memory. As described above, 3D NAND flash memory 930 may comprise, but is not limited to, TLC memory that may be programmed to eight different charge states. Radiation may have the potential to discharge the floating gate at a selected threshold voltage Vth and thus, impend cells may appear in a low charge state (i.e., the second charge state). An appropriate read Vth may be selected to obtain an optimal cell cloud density of a 3D sub-capacity suitable for density-based clustering.

[0037] Method 800 may proceed from step 810, where a flash control device 935 determines a plurality of logical addresses respectively associated with a plurality of cells of a 3D NAND flash memory 930 inverted from a first charge state to a second charge state, to step 820, where a computer device 900 or a control device 935 converts the plurality of logical addresses into a plurality of physical addresses associated with the plurality of cells of the 3D NAND flash memory 930 inverted from the first charge state to the second charge state. For example, in order to appropriately reconstruct and identify radiation-induced 3D tracks, a conversion from a logical address to a physical address may be required. The reason is that the data of the 3D flash memory may be scrambled in order to remove electromagnetic crosstalk between cells and improve storage security.

[0038] In step 820, when a computing device 900 or a control device 935 converts a plurality of logical addresses into a plurality of physical addresses associated with a plurality of cells of a 3D NAND flash memory 930 inverted from a first charge state to a second charge state, method 800 may proceed to step 830 where the computing device 900 or the control device 935 may determine a plurality of tracks of the plurality of cells associated with the plurality of physical addresses. For example, an optimal memory capacity for 3D image processing may be determined from an estimation of an optimal number of radiation-induced inversion cells and readout noise for high-speed density-based clustering processing. This is, for example, for a particular 3D NAND device, 240×240 cells in the lateral direction each having a size of about 150 nm×150 nm and 92 layers having a spacing of about 40 nm in the longitudinal direction. As a result, the secondary capacity of this example is about 36×36×4 microns in size. The optimal density of the inversion cells in the secondary capacity was selected to be between 500 inversions and 2000 inversions (see FIG. 3).

[0039] The 3D clustering algorithm for the process according to embodiments of the present disclosure may be used to distinguish radiation-induced cell inversion from the background of cell inversion related to the holding effect. Embodiments of the present disclosure provide high efficiency for clusters of i) "standard" shapes (e.g., lines, semi-circles, etc.), ii) do not require prior knowledge of the expected number of clusters, and iii) can be stable against noise. Thus, embodiments of the present disclosure may use, for example, 3D density-based spatial clustering (3D-DBSCAN) for applications with noise as the clustering process. The 3D-DBSCAN process is based on the assumption that if a point belongs to a cluster, the point is located near other points of the cluster, and is shown by FIG. 4. Other clustering processes (e.g., hierarchical clustering) may be used.

[0040] Small clusters located along the same straight line may be "connected". The connection of clusters may depend on the fact that most of the radiation-induced clusters appear as linear tracks. Thus, vectors may be associated with the tracks. A series of vector algebraic operations may be performed on the vectors associated with each track to establish the angle between two vectors and the distance between the centroids of each vector. Two sub-tracks are considered parallel and form one track if the vector angles and distances are within the specified allowable ranges (see FIG. 5).

[0041] Clusters may be selected using shape parameters. The elongated linear shape of radiation-induced tracks may form the basis of a "shape parameter" that may effectively select only linear tracks. The shape parameter may be the gradient of cluster points along orthogonal axes or along the principal eigenvectors of the cluster. For example, only tracks with a shape parameter greater than a specified value may be retained. In contrast to a memory chip irradiated with heavy charged particles or neutrons, a memory chip irradiated with gamma photons may produce distinguishable curvilinear or spherical tracks and may be identified using image processing and shape filtering methods based on clustering density and a trained convolutional neural network (CNN) classification algorithm. In step 840, when the computer device 900 or the control device 935 determines a plurality of tracks of a plurality of cells associated with a plurality of physical addresses, method 800 may end in step 850.

[0042] The dose range of conventional track detectors may be limited to relatively low neutron doses because at high doses the tracks may begin to overlap and image processing of individual tracks may be difficult. To expand the dose range, embodiments of the present disclosure may use 3D fast Fourier transform (FFT) processing. Another approach for high-dose measurements may be determined as a total ionizing dose (TID) process that includes the cumulative number of radiation inversion cells for each sub-capacitance or the entire memory die.

[0043] The neutron energy range may be determined by the number and type of neutron converters that enable detection of neutrons typically from a thermal energy of 0.025 eV to a high energy of 100 MeV. For flash-based devices, there may be an upper limit to the neutron energy range because the linear energy transfer (LET) of recoil protons for high neutron energies is small and the energy accumulation in memory cells is low.

[0044] FIG. 9 shows a computer device 900. As shown in FIG. 9, the computer device 900 may have a processing device 910 and a storage device 915. The storage device 915 may have a software module 920 and a database 925. When executed by the processing device 910, the software module 920 may perform processing to provide, for example, a method for processing a digital neutron dosimeter based on a 3D NAND flash memory as described above with respect to FIG. 8.

[0045] The digital neutron dosimeter according to an embodiment of the present disclosure may have a 3D NAND flash memory 930 (for example, a flash memory chip packaged with a neutron converter) and a control device 935 (for example, a flash readout controller and wireless). An additional low-power microcontroller may be utilized to undertake other dosimeter functions such as sleep mode, wake-up on demand or at predetermined time intervals, and communication with other parts of the dosimeter dedicated to photon detection and motion detection.

[0046] Limited data processing may be performed by the dosimeter itself. For example, about 10 -4 ~10 -5 of the total number of readout cells may be read by the control device 935 and considered for streaming and processing by the computing device 900. These readout cells may comprise a sum of cells representing readout noise and cells representing radiation-induced cell inversions that have been discharged. The conversion from a logical address to a physical address may be performed by the dosimeter or transmitted (for example, streamed) to the computer device 900 for performing the conversion. The above-described processing for determining tracks and the number of tracks may be performed by the computer device 900.

[0047] The elements described above with reference to FIG. 9 (e.g., computer device 900, 3D NAND flash memory 930, and control device 935) may be implemented in hardware and / or software (including firmware, resident software, microcode, etc.) or any other circuit or system. The elements described above with reference to FIG. 9 may be implemented in an electric circuit including discrete electronic elements, a packaged or integrated electronic chip having logic gates, a circuit or electronic element using a microprocessor, or a single chip including a microprocessor. Further, the elements described above with reference to FIG. 9 may be implemented using other techniques capable of performing logical operations such as AND, OR, and NOT, including but not limited to mechanical techniques, optical techniques, fluid techniques, and quantum techniques.

[0048] As described above, radiation-induced tracks are identified, discriminated, and counted with read noise as the background. The number of tracks is proportional to the dose accumulated in the dosimeter. FIG. 10 shows, for example, experimental results of the dose dependence of the number of tracks for fast AmBe neutrons and thermal neutrons.

[0049] Embodiments of the present disclosure may include a method for accurately determining an unknown neutron dose by combining the use of a 3D NAND flash memory die coated with a neutron converter, a read process using a predetermined threshold voltage, a conversion from a logical address to a physical address, and a mathematical algorithm for 3D sub-capacity image processing for track identification and counting.

[0050] Embodiments of the present disclosure may include polyethylene and / or 6 Li-containing glass, 10 B-containing glass or plastic, and / or a thin sheet / plate of polytetrafluoroethylene, the latter being intended for photon-induced signal subtraction.

[0051] Embodiments of the present disclosure may include, in addition to a 3D NAND memory chip, a memory controller and a wireless transmitter for streaming data to a base station or a mobile device.

[0052] Embodiments of the present disclosure may include using one or more threshold voltages selected to obtain an optimal density of inversion cells of a selected sub-capacity of a memory die for high-speed and reliable density-based clustering processing such that a read process discriminates radiation-induced tracks and distinguishes these tracks from randomly distributed inversion cells identified as noise.

[0053] Embodiments of the present disclosure may include factory-based initial dosimeter setting and calibration including erasing, programming, and pre-irradiation reading of each flash chip and loading firmware to a controller chip.

[0054] Embodiments of the present disclosure may include 3D image and dose processing mathematical algorithms comprising clustering based on the density of each inversion cell of a selected sub-capacity of a die to identify cells belonging to the same track, cluster shape evaluation to identify elongated-shaped clusters and identify and connect clusters that are adjacent or located on the same straight line assuming these sub-clusters belong to the same track, and calculating the track density per unit area of a 3D NAND die that is proportional to the neutron dose and inversely proportional to a calibration coefficient set during factory calibration while counting the total number of tracks.

[0055] Embodiments of the present disclosure may include performing 3D image processing using mathematical procedures based on fast Fourier transform and power spectrum integration calculations to expand the dynamic range of dose measurement and avoid saturation of the dosimeter for high-density tracks and inversion cells.

[0056] Embodiments of the present disclosure may include non-destructive reading of an irradiated dosimeter executed multiple times using predetermined parameters.

[0057] Embodiments of the present disclosure may include irradiating a radiation dosimeter with a known radiation dose to calibrate the device and determine values of control parameters and calibration coefficients.

[0058] Embodiments of the present disclosure may include 3D NAND flash memory based on floating gate cell technology.

[0059] Embodiments of the present disclosure may include 3D NAND flash memory based on charge trapping cell technology.

[0060] Embodiments of the present disclosure may include a wireless device / devices that combines one or more 3D NAND flash chips / dies coated with one or more radiation converters, a 3D NAND controller programmed for fast and optimal reading of NAND memory, and a wireless transmitter for streaming data, to highly faithfully determine an unknown radiation dose.

[0061] The computer device 900 may be implemented using a low-power Bluetooth® access point, a tablet device, a mobile device, a smartphone, a remote control device, a personal computer, a network computer, a mainframe, a router, a switch, a server cluster, a smart TV-like device, a network storage device, a network relay device, or other similar microcomputer-based devices. The computer device 900 may include any computer operating environment such as a handheld device, a multiprocessor system, a microprocessor-based, a minicomputer, a mainframe computer, etc. The computer device 900 may be implemented in a distributed computing environment where tasks are executed by a remote processing device. The above-described systems and devices are examples, and the computer device 900 may include other systems or devices.

[0062] Embodiments of the present disclosure may be implemented, for example, as a computer process (method), a computer system, or a manufactured product such as a computer program product or a computer-readable medium. The computer program product may be a computer storage medium encoding a computer program of instructions that is readable by a computer system and that executes a computer process. The computer program product may also be a propagated signal of a carrier encoding a computer program of instructions that is readable by a computer system and that executes a computer process. Accordingly, the present disclosure may be embodied in hardware and / or software (including firmware, resident software, microcode, etc.). In other words, embodiments of the present disclosure may take the form of a computer program product on a computer-usable or computer-readable storage medium having computer-usable or computer-readable program code embodied in the medium for use by or in connection with an instruction execution system. The computer-usable or computer-readable medium may be any medium that can perform storage, preservation, communication, propagation, or transportation of a program for use by or in connection with an instruction execution system, an instruction execution device, or an instruction execution apparatus.

[0063] A computer-usable medium or computer-readable medium may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, device, or propagation medium. More specific examples (a non-exhaustive list) of computer-readable media include a computer-readable medium may include an electrical connection having one or more wires, a portable computer diskette, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, and a portable compact disk read-only memory (CD or DVD-ROM). Note that a computer-usable medium or computer-readable medium may even be paper or other suitable medium on which a program is printed. The reason is that after the program is electronically captured via, for example, optical scanning of paper or other medium, appropriate compilation, interpretation, or other processing is performed as necessary and stored in a computer memory.

[0064] Although specific embodiments of the present disclosure have been described, other embodiments may exist. Further, although embodiments of the present disclosure have been described as related to data stored in memory and other storage media, the data may be stored in or read from other types of computer-readable media such as secondary storage devices such as hard disks, CD / DVD-ROMs, carrier waves from the Internet, or other forms of RAM or ROM. Further, the steps of the disclosed method may be changed in any way including rearrangement of steps and / or insertion or deletion of steps without departing from the present disclosure.

[0065] Furthermore, embodiments of the present disclosure may be implemented in an electric circuit including discrete electronic elements, a packaged or integrated electronic chip having logic gates, a circuit or electronic element using a microprocessor, or a single chip having a microprocessor. Embodiments of the present disclosure may be implemented using other technologies including, but not limited to, mechanical technology, optical technology, fluid technology, and quantum technology that can perform logical operations such as, for example, AND, OR, and NOT. Furthermore, embodiments of the present disclosure may be implemented within a general-purpose computer or in any other circuit or system.

[0066] Embodiments of the present disclosure may be implemented via a system-on-chip (SOC) in which each or many of the elements shown in FIG. 9 are integrated on a single integrated circuit. Such an SOC device may have one or more processing devices, graphic devices, communication devices, system virtualization devices, and various application functions, all of which may be integrated (or “burned in”) on a chip substrate as a single integrated circuit. When operating via an SOC, the functions described herein with respect to embodiments of the present disclosure may be executed via application-specific logic integrated with other components of a computer device 900 on a single integrated circuit (chip).

[0067] Embodiments of the present disclosure have been described above with reference to, for example, block diagrams and / or operation diagrams of methods, systems, and computer program products according to embodiments of the present disclosure. The functions / operations described in the blocks may occur out of the order shown in any flowchart. For example, two blocks shown consecutively may actually be executed substantially simultaneously, or the blocks may sometimes be executed in the reverse order depending on the related functions / operations.

[0068] This specification includes examples, but the scope of the present disclosure is indicated by the following claims. Furthermore, although this specification has been described in language specific to structural features and / or methodological acts, the claims are not limited to the features or acts described above. Rather, the specific features and acts described above are disclosed as examples of embodiments of the present disclosure.

Claims

1. Determining a plurality of logical addresses respectively associated with a plurality of cells of a three-dimensional NAND (3D NAND) flash memory inverted from a first charge state to a second charge state; Converting the plurality of logical addresses into a plurality of physical addresses respectively associated with the plurality of cells of the 3D NAND flash memory inverted from the first charge state to the second charge state; Determining a plurality of tracks of the plurality of cells associated with the plurality of physical addresses and caused by neutron rays, beta rays or photon rays; A method comprising the above steps.

2. The method according to claim 1, further comprising providing values associated with the determined plurality of tracks.

3. The method according to claim 1, wherein determining the plurality of tracks of the plurality of physical addresses comprises using density-based clustering.

4. The method according to claim 1, wherein the 3D NAND flash memory comprises a converter outside the die of the 3D NAND flash memory.

5. The converter is made of polyethylene, ６ Li-containing glass, １０ The method according to claim 4, comprising one of B-containing glass, plastic, and polytetrafluoroethylene.

6. The method according to claim 1, further comprising determining an optimal number of inverted cells in the second charge state.

7. The method according to claim 1, wherein the plurality of cells comprise floating gate transistor cells.

8. The method according to claim 1, wherein the plurality of cells comprise charge trapping cells.

9. The method according to claim 1, further comprising setting the cells of the 3D NAND flash memory to the first charge state before determining the plurality of logical addresses respectively associated with the plurality of cells of the inverted 3D NAND flash memory.

10. A memory device; A processing unit coupled to the memory device, Determining a plurality of logical addresses respectively associated with a plurality of cells of a 3D NAND flash memory inverted from a first charge state to a second charge state, A processing unit operative to convert the plurality of logical addresses into a plurality of physical addresses respectively associated with the plurality of cells of the 3D NAND flash memory inverted from the first charge state to the second charge state; A system comprising the above components.

11. The system according to claim 10, wherein the processing unit is further operative to transmit the plurality of physical addresses.

12. The system according to claim 10, wherein the 3D NAND flash memory comprises a converter outside the die of the 3D NAND flash memory.

13. The converter is made of polyethylene, ６ Li-containing glass, １０ The system according to claim 12, comprising one of B-containing glass, plastic, and polytetrafluoroethylene.

14. The system according to claim 10, wherein the plurality of cells comprise floating gate transistor cells.

15. The system according to claim 10, wherein the plurality of cells comprise charge trapping cells.

16. A computer-readable medium storing a set of instructions that, when executed, perform a method, the method comprising: determining a plurality of logical addresses respectively associated with a plurality of cells of a 3D NAND flash memory inverted from a first charge state to a second charge state; converting the plurality of logical addresses to a plurality of physical addresses associated with the plurality of cells of the 3D NAND flash memory inverted from the first charge state to the second charge state; A computer-readable medium comprising the above.

17. The computer-readable medium according to claim 16, wherein the dosimeter sensor of the 3D NAND flash memory comprises a converter outside the die of the 3D NAND flash memory.

18. The converter is polyethylene, ６ Li-containing glass, １０ The computer-readable medium according to claim 17, comprising one of B-containing glass, plastic, and polytetrafluoroethylene.

19. The computer-readable medium according to claim 16, wherein the plurality of cells comprise floating gate transistor cells.

20. The computer-readable medium according to claim 16, wherein the plurality of cells comprise charge trapping cells.

Images