Method and device for multielement analysis on the basis of neutron activation, and use

Abstract

A method for a multielement analysis via neutron activation. The method includes generating fast neutrons with an energy in the range of 10 keV to 20 MeV and moderating the neutrons, irradiating the sample with the neutrons, and measuring the gamma radiation emitted by the irradiated sample using a detector to determine at least one element of the sample. The sample continuously irradiated in a non-pulsed fashion. The measurement is implemented during the irradiation. The determination of the at least one element includes an evaluation of the measured gamma radiation. The sample is subdivided into individual partitions and the measurement is implemented using a collimator. The evaluation includes a spatially resolved and energy-resolved determination of the neutron flux within the respective partition of the sample and calculation of energy-dependent photopeak efficiencies and neutron flux and neutron spectrum within a single partition of the sample by an approximation method.

Claims

1. A method for a multielement analysis on the basis of neutron activation, the method comprising: generating fast neutrons with an energy in the range of 10 keV to 20 MeV and moderating the neutrons; irradiating the sample with the neutrons; and measuring the gamma radiation emitted by the irradiated sample by means of at least one detector in order to determine at least one element of the sample, wherein, the sample is irradiated continuously in non-pulsed fashion, the measurement is implemented during the irradiation, at least prompt or both prompt and delayed gamma radiation from the continuous neutron irradiation is measured and evaluated for the purposes of determining the at least one element, the sample is subdivided into individual partitions and the measurement is implemented using a collimator, surrounding the respective detector, in respect of the respective partitions, the determination of the at least one element comprises an evaluation of the measured gamma radiation, and the evaluation comprises a spatially resolved and energy-resolved determination of the neutron flux within the respective partition of the sample and calculation of energy-dependent photopeak efficiencies and neutron flux and neutron spectrum within a single partition of the sample by an approximation method.

2. The method as recited in claim 1, wherein the irradiation and measurement is implemented over a period of time of at least one second.

3. The method as recited in claim 1, wherein, only delayed gamma radiation from continuous neutron irradiation is measured and evaluated, at least intermittently, in order to determine the at least one element, or the measurement or determination is implemented on an individual basis in respect of the individual partitions of the sample, said partitions being predefined or predeterminable manually or automatically by way of collimation.

4. The method as recited in claim 1, wherein, for the purposes of determining the at least one element, the gamma radiation emitted by the sample is measured in energy-resolved fashion by determining photopeak count rates, and the determination comprises an energy-resolved evaluation of the measured gamma radiation in accordance with gamma spectra of the respective partitions.

5. The method as recited in claim 1, wherein the measurement/evaluation comprises an energy-resolved measurement/evaluation of the intensity of the gamma radiation emitted by the sample.

6. The method as recited in claim 1, wherein, the evaluation comprises correlating, on the basis of its energy, at least one photopeak in the count rate-energy diagram with an element of the sample, or the evaluation further comprises quantifying the mass fraction of the at least one element of the sample by virtue of the component of the at least one element contained in the sample being evaluated after subtracting a background signal from the net area of a/the photopeak, which is caused by the element in a count rate-energy diagram.

7. The method as recited in claim 1, wherein the neutron flux within the respective partition of the sample is calculated on the basis of a diffusion approximation of the linear Boltzmann equation, in particular on the basis of the following relationship:
Φ(x,E.sub.n)=∫.sub.s2 Ψ(x,E.sub.n,Ω)dΩ.

8. The method as recited in claim 1, wherein the calculation of energy-dependent photopeak efficiencies and neutron flux and neutron spectrum within an individual partition of the sample by calculating neutron flux and neutron spectrum by way of an approximation method is implemented in each case on the basis of the following relationship:
Φ(x,E.sub.n)=∫.sub.s2 Ψ(x,E.sub.n,Ω)dΩ.

9. The method as recited in claim 1, wherein, during the evaluation, a multiplicity of gamma energies, respectively of at least one element in the respective partition of the sample, are analyzed when quantifying the mass fraction of the respective element in the respective petition, said analysis being based on the following relationship: ${\left(P_R\right)}_{E_{\gamma }}^i=\frac{N_A}{M}.Math.\underset{k=1}{\overset{K}{.Math.}}{m}_k.Math.{\mathrm{.Math.}}_{E_{\gamma }}^{i\leftarrow k}.Math.{\sigma }_{E_{\gamma }}^{\mathrm{ik}}.Math.{\Phi }_k^i.$

10. The method as recited in claim 1, wherein, the method is carried out on the basis of the input variables of neutron source strength, sample geometry and sample mass, in particular exclusively on the basis of said three input variables, and the method is carried out iteratively, in each case with respect to individual elements and/or with respect to the respective partition of the sample and/or with respect to the complete composition of the sample.

11. The method as recited in claim 1, wherein the method is carried out in automated fashion by evaluating the measured gamma radiation on the basis of purely numerically ascertained parameters apart from the three parameters of neutron source strength during the irradiation, sample geometry and sample mass.

12. The method as claimed in claim 1, wherein the spatially resolved and energy-resolved determination of the neutron flux, in particular of the total neutron flux of a respective partition, is implemented within the sample chamber and outside of the sample, in particular by means of a plurality of neutron detectors disposed within the sample chamber.

13. A computer program product configured to carry out a multielement analysis on the basis of neutron activation as per the method as recited in claim 1 when the method is executed on a computer and configured to determine at least one element of a sample, irradiated in non-pulsed continuous fashion with neutrons, by evaluating at least prompt or else prompt and delayed gamma radiation, emitted by the sample, in respect of the composition of the sample on the basis of energy-dependent photopeak efficiencies and neutron flux and neutron spectrum within a respective partition of the sample, and further configured to evaluate gamma radiation measured in partition-collimated fashion by virtue of a plurality of gamma energies, respectively of the at least one element, being analyzed in the respective partition of the sample when quantifying the mass fraction of the respective element of the respective partition on the basis of the net photopeak count rate registered during the multielement analysis, in particular on the basis of the following relationship: ${\left(P_R\right)}_{E_{\gamma }}^i=\frac{N_A}{M}.Math.\underset{k=1}{\overset{K}{.Math.}}{m}_k.Math.{\mathrm{.Math.}}_{E_{\gamma }}^{i\leftarrow k}.Math.{\sigma }_{E_{\gamma }}^{\mathrm{ik}}.Math.{\Phi }_k^i.$

14. An apparatus configured to carry out a multielement analysis on the basis of neutron activation as per the method as recited in claim 1, the apparatus comprising: a neutron generator configured to generate fast neutrons; a sample chamber and a sample holder disposed therein; and a detector unit comprising at least one detector configured to measure gamma radiation emitted by an irradiated sample, for the purposes of determining at least one element of the sample, wherein, the apparatus comprises a control device that is configured to carry out a method as claimed in claim 1, the apparatus is configured to irradiate a/the sample in non-pulsed continuous fashion, the apparatus comprises at least one collimator that restricts the field of view of the detector to a respective partition of the sample, and the apparatus is configured to evaluate the measurements of the partitions by quantifying the mass fraction of the at least one element of the sample.

15. The apparatus as recited in claim 14, wherein the neutron generator comprises a neutron source configured to fuse deuterons, in particular using deuterium gas as a fuel.

16. The apparatus as recited in claim 14, wherein the apparatus comprises at least one component that attenuates a background signal of the apparatus, said component being selected from the following group: at least one collimator made of lead or bismuth, said collimator restricting the field of view of the detector to the respective partition of the sample, and/or a moderation chamber made of graphite, and/or a shielding made of borated polyethylene, and/or a sample chamber and/or a sample carrier, each at least partly made of graphite or completely fluorinated plastics or beryllium.

17. The apparatus as recited in claim 14, further comprising: a computer program product or a data memory therewith, wherein, the computer program product is configured to determine the at least one element of the sample by evaluating the measured gamma radiation on the basis of energy-dependent photopeak efficiencies and a neutron flux and neutron spectrum within the respective partition of the sample.

18. The apparatus as recited in claim 14, wherein the detector unit comprises at least two detectors, in particular in symmetric arrangement relative to the neutron generator or relative to at least one neutron source of the apparatus.

19. The apparatus as recited in claim 14, wherein the neutron generator is configured to fuse deuterons for the purposes of generating fast neutrons.

20. An apparatus configured to carry out the multielement analysis on the basis of a neutron activation as per the method as recited in claim 1.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) The invention will still be described in more detail in the following figures of the drawing, with reference being made to the other figures of the drawing for reference signs that are not explicitly described in a respective figure of the drawing. In detail:

(2) FIG. 1 shows a perspective view of a schematic illustration of an apparatus for nondestructive multielement analysis according to an exemplary embodiment;

(3) FIGS. 2A, 2B, 2C each show a sectional view of a sample chamber with one or two detectors as well as a detector in a detailed view, in each case of an apparatus for nondestructive multielement analysis according to an exemplary embodiment;

(4) FIG. 3 shows, in a flowchart, a schematic illustration of individual steps of a method according to an embodiment;

(5) FIG. 4 shows a cylindrical sample with a partitioning in the form of disk segments as an example for partitioning in a method according to an embodiment;

(6) FIG. 5 shows a sectional view of a sample chamber with, disposed outside of a shielding, a rotation and lifting device of an apparatus according to one exemplary embodiment; and

(7) FIG. 6 shows a schematic illustration of a sample chamber with, disposed therein, neutron detectors of a neutron detector unit of an apparatus for nondestructive multielement analysis according to one exemplary embodiment.

DETAILED DESCRIPTION OF THE FIGURES

(8) FIG. 1 shows an assembly of an apparatus 10 for nondestructive multielement analysis, to be precise in the style of a measuring installation for carrying out the method, described herein, for multielement analysis on the basis of neutron activation.

(9) By operating one or more neutron generators 11, a sample 1 is continuously irradiated by neutrons and the gamma radiation induced/emitted thereby is measured concurrently with the irradiation. The apparatus/measuring installation 10, including the sample 1, consists, in particular, of the following assemblies: The neutron generator 11 comprises at least one electrically operated neutron source, in particular a neutron source that fuses at least deuterium and deuterium (or deuterons) and, optionally, facilitates a further type of fusion, in particular tritium and deuterium. Fast neutrons with an energy of 2.45 MeV are emitted during the deuteron fusion reaction. Here, deuterium gas is preferably used as a target (non-radioactive). Optionally, at least one further energy value, in particular 14.1 MeV, can be provided by means of the neutron generator. The neutron generator 11 is situated within a moderation chamber 12 and surrounded by a shielding 19. The moderation chamber 12 consists of a material, preferably graphite, that moderates fast neutrons as effectively as possible and that emits as little gamma radiation as possible during the moderation process. Gamma radiation not emitted by the sample but nevertheless registered by the detector is defined as an active background signal. The apparatus 10 described herein advantageously supplies a very weak, minimized background signal, and so gamma radiation can be measured very flexibly.

(10) During the irradiation, the sample 1 is situated on a sample carrier 14 in the interior of a sample chamber 15. By way of example, the sample carrier can be a rotary plate, a box, a can or a flask. Preferably, graphite and completely fluorinated plastics can be used as material for the sample carrier 14.

(11) The sample carrier 14 and the sample chamber 15 are designed such that the sample is irradiated as homogeneously as possible by the neutrons (i.e., with a small local neutron flux gradient) and that neutrons that deviate from the sample are effectively reflected back into the sample. An active background signal that, where possible, is only weak should be caused during the interactions between the neutrons and the sample carrier 14 and between the neutrons and the sample chamber 15. In particular, this can be ensured by virtue of graphite, beryllium and completely fluorinated or carbon fiber reinforced plastics preferably being used as a material for the sample carrier 14 and the sample chamber 15.

(12) The gamma spectrum measured concurrently with the irradiation is recorded by a detector unit 16 or by one or more detectors 16A, 16B. Both one detector and a plurality of detectors can be understood to mean a detector unit 16. The measurement time of a sample can be reduced by way of a plurality of detectors or the sensitivity and accuracy of the multielement analysis method can be increased in the case of an unaltered measurement time. The detector unit 16 registers the energy of the gamma radiation emitted by the sample and counts the energy depositions in the detector. A collimator 17 is situated around each detector 16. The respective collimator can be used to restrict the “field of view” of the employed detectors in such a way that predominantly gamma radiation emitted by the sample is detected. The spatial region with an elevated detection probability for gamma radiation has, in particular, the form of a cone or a pyramid proceeding from the detector. The collimator 17 is manufactured from a material, preferably lead, that shields gamma radiation as effectively as possible. Thanks to the restricted field of view of the detector, the collimator allows a minimization or attenuation of the active background signal.

(13) The sample can be measured in segmented/partitioned fashion. To this end, it is not the entire sample body but only individual segments, so-called partitions, that are situated in the collimated field of view of the detector during a single gamma-spectrometric measurement. For the purposes of positioning the individual partitions in the field of view of the detector, a rotation and lifting apparatus 18 is provided to rotate and/or translate the sample and the sample carrier. The rotation and lifting apparatus and the sample carrier are connected to one another, in particular in force-fit and/or interlocking fashion. Since the components of the rotation and lifting apparatus could increase the active background signal, these assemblies are preferably positioned outside of the sample chamber and moderation chamber 15, 12 and outside of the shielding 19 (FIG. 5). In particular, a shaft, chain or a toothed belt can be used to transfer force between the rotation and lifting apparatus and the sample carrier 14.

(14) The shielding 19 is disposed around the moderation chamber and sample chamber 12, 15 and around the detector unit 16 and around the collimator 17. The shielding 19 surrounds the measuring installation and reduces the neutron and gamma ambient dose rate outside of the measuring installation. Preferably, borated polyethylene is used as a material for the part of the shielding that primarily shields neutron radiation. Concrete and elements with higher atomic number and higher density, for example steel or lead, can be used as materials for the part of the shielding that primarily reduces or attenuates the gamma radiation. It was found that the SNR can be significantly improved by borated polyethylene in the region of the moderation chamber and sample chamber 12, 15 and there around, and around the detector unit 16 and around the collimator 17.

(15) FIG. 1 further indicates that at least one of at least three variables/parameters v1, v2, v3, in particular the neutron source strength, the sample geometry and/or the sample mass, can be entered or recalled at the input mask 23. According to one variant, these three parameters can also be ascertained by the apparatus 10 in fully automated fashion.

(16) In the arrangement shown in FIG. 1, moderation can be carried out in a separate moderation chamber 12 outside of the sample chamber 15. Optionally, moderation can also be carried out within the sample chamber 15. In general, moderation can be carried out in the moderation chamber 12, the sample chamber 15 and/or in the sample 1 itself.

(17) FIG. 1 further shows a transmission measuring unit 24, by means of which an additional characterization of the sample can optionally be carried out, in particular on the basis of gamma radiation.

(18) FIG. 1 further indicates components for automating the measurement or evaluation, in particular a control device 20, which is coupled to a data memory 21, to a nuclear physics database 22, to an input unit/input mask 23, to a transmission measuring unit 24, to a camera unit 25, to a weighing unit 27, and/or to a computer program product 30, wherein the latter may also be stored in the control device 20.

(19) FIGS. 2A, 2B, 2C show an apparatus for nondestructive multielement analysis, by means of which there is a collimated measurement of partitions of a sample. In the variant shown in FIG. 2A, the two detectors 16A, 16B are disposed symmetrically relative to a neutron source or to a neutron source point 11.1 of the neutron generator 11.

(20) In detail, FIGS. 2A, 2B, 2C also show the preferably employable materials, in particular materials for ensuring a weak background signal, in particular borated polyethylene M1 (in particular 5 or 10%) for the shielding 19 of neutron radiation (also concrete in sections for the shielding 19 of gamma radiation), lead or bismuth M2 for the collimator 17 or for the purposes of shielding gamma radiation, graphite M3 for the moderation chamber 12 or the sample carrier 14 or the sample chamber 15, lithium-6-polyethylene or lithium-6-silicone M6 for shielding the detector, germanium M10 for the crystal 16.1. A region between individual components of the detector 16, in particular between the detector end cap 16.2 and the crystal 16.1, is filled with air M4, in particular in the interior of the collimator. Depending on the type of neutron generator or detector, adequate materials M7, M8 can be chosen for individual further components, in particular from the list comprising copper, aluminum, plastic (in particular carbon-fiber reinforced).

(21) FIG. 2A shows, in exemplary fashion, two partitions P1, P2 of n partitions Pn in the form of cylinder segments (cake slices) in the case of a cylindrical sample 1. Here, the sample 1 may also be provided by a drum, with a certain fill level of a fill or a fluid. The drum may have a relatively large volume, e.g., 200 liters.

(22) FIG. 2A moreover allows identification of the alignment of the individual components as per the longitudinal axis x, the transverse axis y and the vertical axis z. The sample is cylindrical, at least in portions, or, e.g., embodied as a drum and it extends along the vertical axis z, in particular in rotationally symmetric fashion about the z-axis. Positioning at different z-levels is possible by means of the aforementioned lifting device 18.

(23) FIG. 2B shows a variant with only one detector 16, which is collimated on a cylinder segment. This arrangement can also be provided in cost-optimized fashion, in particular.

(24) In the arrangement respectively shown in FIGS. 2A and 2B, a moderation may also be carried out exclusively within the sample chamber 15.

(25) FIG. 2C further shows a detector end cap 16.2 and a crystal holder 16.3, it being possible to position and align the crystal 16.1 by means of said elements.

(26) FIG. 3 shows a method in six steps S1 to S6, said steps each comprising sub-steps. Control points R1 to R5 may be provided between the individual steps, be it for user query, be it for an automatic, computer-controlled query.

(27) Generating neutrons and irradiating a sample with neutrons is implemented in a first step S1, wherein the first step may include at least one of the following sub-steps: setting (controlling or regulating) the neutron source strength (S1.1), moderation (S1.2), calculating the neutron spectrum by simulation (S1.3), calculating the neutron flux by simulation (S1.4). There can be, in particular, an optionally repeated query in respect of the neutron source strength at a first control point R1, be this an automated data query, be this within the scope of a user input/user guidance.

(28) A sample is specified and measured in a second step S2, wherein the second step may include at least one of the following sub-steps: detecting the sample mass and, optionally, also the sample geometry (S2.1), collimation (S2.2), detecting or setting the sample partitioning (S2.3), displacing/positioning the sample, in particular by translation and/or rotation (S2.4). Step S2.1 can be implemented in conjunction with a transmission measurement, in particular by virtue of radioactive gamma radiation being emitted toward the sample, for example for detecting a fill level in a drum (sample), or for determining a matrix density. The transmission measurement can also be considered to be an extended measurement for characterizing the sample and may supply further data, in particular also in respect of a partitioning that is as useful as possible. There can be, in particular, an optionally repeated query in respect of the sample mass, sample geometry and partitioning in a second control point R2, be it an automated data query in communication with a camera unit and/or a weighing unit, be it within the scope of a user input/user guidance. In particular, positioning or alignment of the sample can also be implemented at the second control point R2.

(29) Emitted gamma radiation is detected or measured in a third step S3, wherein the third step may include at least one of the following sub-steps: detecting/measuring gamma radiation and evaluating the gamma spectrum (S3.1), element/peak identification (S3.2), interference analysis (S3.3), evaluation of peaks, in particular evaluation in respect of area and background (S3.4). In particular, a transfer and verification of intermediate results can be implemented at a third control point FR3. Here, the control point R3 may comprise a plausibility check, in particular within the scope of a statement about the homogeneous element and mass distribution in the sample or in the respective partition, wherein there may optionally be an iteration back to step S2 (for example in the case of a deviation that is greater than a maximum threshold), in particular in order to measure on the basis of a new collimated approach.

(30) Measured gamma radiation is evaluated in a fourth step S4, in particular in order to calculate the energy-dependent photopeak efficiency, wherein the fourth step may include at least one of the following sub-steps: evaluating interactions within the sample (S4.1) for calculating the energy-dependent photopeak efficiencies, evaluating interactions in a respective detector (S4.2), determining the solid angle between sample and detector (S4.3), determining photopeak efficiencies, in particular (initial) photopeak efficiencies (S4.4). In particular, a transfer and verification of intermediate results can be implemented at a fourth control point R4.

(31) The mass of at least one element is determined in a fifth step S5, wherein the fifth step may include at least one of the following sub-steps: determining at least one elemental mass or determining elemental mass ratios (S5.1), determining at least one cross section (S5.2), in particular from either step S1 or step S4, respectively. In particular, a transfer and verification of intermediate results can be implemented at a fifth control point R5. Here, the control point R5 can comprise a plausibility check, in particular a juxtaposition or comparison of quantified elemental masses and the overall mass of the sample.

(32) The neutronics are calculated in a sixth step S6, wherein the sixth step may include at least one of the following sub-steps: evaluating interactions, in particular neutron interactions within the sample (S6.1), in particular by way of a diffusion approximation, evaluating a neutron spectrum (S6.2), evaluating a neutron flux (S6.3), in particular by diffusion approximation.

(33) Control points R1 to R5 may each comprise an optional feedback (control loop) to the preceding step, in particular within the scope of a verification of a user input or an intermediate result. Steps S4 to S6 can be carried out iteratively, independently of the individual control points, in particular continuously during the evaluation of gamma radiation from continuously irradiated samples. The iteration is terminated if the elemental mass to be determined no longer changes or at least no longer changes substantially, for example below a predeterminable threshold for a difference.

(34) FIG. 4 shows the field of view of a respective detector 16A, 16B using the example of a cylindrical sample 1 that has been partitioned into disks and circular segments P1, P2, Pn. Here, the field of view of the respective detector 16A, 16B need not necessarily correspond to, or lie flush with, a respective partition. To what extent an adjacent partition lies in the field of view of the respective detector can be taken into account during the evaluation, said adjacent partition being intended to be evaluated concurrently or removed by calculation. There are 12 partitions present at each level. Then, the entire sample can be analyzed by six rotations and the corresponding number of translational level displacement steps (here, there are five levels, i.e., four displacement steps in the z-direction). By way of example, each partition is irradiated and measured over a period of time of a few seconds to minutes.

(35) FIG. 5 shows an apparatus 10, in which the sample carrier 14 can be displaced upward in terms of its level by a significant distance (arrow with dotted line). The sample chamber 15 is delimited by material M3, it being possible to displace said material M3 together with the sample 1 into an air-filled cavity above the sample 1. The rotation and lifting device 18 is connected to the sample carrier 14 by means of a coupling comprising a shaft 18.1; apart from this, however, said rotation and lifting device is disposed outside of the neutron shielding and sealed off from the sample chamber. This can ensure that the neutrons do not reach the rotation and lifting device. A pathway for the neutrons to the rotation and lifting device is prevented. The material guiding the shaft 18.1 is preferably graphite. As indicated in FIG. 5, a passage for the shaft 18.1 can be provided in a graphite block. Preferably, the rotation and lifting device 18 is only connected to the sample carrier 14 by means of the shaft 18.1. The neutron shielding is only penetrated by the shaft in that case. The rotation and lifting device is disposed in sealed-off fashion behind the effective neutron shielding.

(36) FIG. 6 shows an apparatus 10 for nondestructive multielement analysis, in which four neutron detectors 28A, 28B, 28C, 28D of a neutron detector unit 28 are disposed in the sample chamber 15. The neutron detectors disposed in exemplary fashion here are disposed with a uniform distribution about the circumference of the sample chamber 15. Optionally, more than four neutron detectors may also be provided. The neutron detectors are preferably disposed on the installation level of the gamma detectors. The neutron detector unit 28 can bring about a spatially resolved and energy-resolved determination of the neutron flux, in particular the absolute or total neutron flux of a respective partition, externally from the sample.

LIST OF REFERENCE SIGNS

(37) 1 Sample

(38) 10 Apparatus for multielement analysis on the basis of neutron activation

(39) 11 Neutron generator

(40) 11.1 Neutron source or neutron source point

(41) 12 Moderation chamber

(42) 14 Sample carrier

(43) 15 Sample chamber

(44) 16 Detector unit

(45) 16A, 16B Individual detector

(46) 16.1 Crystal of an individual detector

(47) 16.2 Detector end cap

(48) 16.3 Crystal holder

(49) 17 Collimator

(50) 18 Rotation and lifting device

(51) 18.1 Coupling, in particular shaft

(52) 19 Shielding

(53) 20 Control device

(54) 21 Data memory

(55) 22 Nuclear physics database

(56) 23 Input unit/mask

(57) 24 Transmission measuring unit

(58) 25 Camera unit

(59) 27 Weighing unit

(60) 28 Neutron detector unit

(61) 28A, 28B, 28C, 28D Individual neutron detector

(62) 30 Computer program product

(63) A16 Visual axis of the detector

(64) M1 Material 1, in particular borated polyethylene and/or cement

(65) M2 Material 2, in particular lead and/or bismuth

(66) M3 Material 3, in particular graphite

(67) M4 Material or medium 4, in particular air

(68) M6 Material 6, in particular lithium polyethylene and/or lithium silicone

(69) M7 Material 7, in particular aluminum and/or carbon fiber reinforced plastic

(70) M8 Material 8, in particular copper or plastic

(71) M10 Material 10, in particular germanium

(72) P1, P2, Pn Partitions of the sample

(73) R1 First control point

(74) R2 Second control point

(75) R3 Third control point

(76) R4 Fourth control point

(77) R5 Fifth control point

(78) S1 First step, in particular generating neutrons and irradiating by neutrons

(79) S1.1 Setting (controlling or regulating) the neutron source strength

(80) S1.2 Moderation

(81) S1.3 Calculating the neutron spectrum by simulation

(82) S1.4 calculating the neutron flux by simulation

(83) S2 Second step, in particular sample specification and measurement

(84) S2.1 Detecting sample mass and/or sample geometry and/or a transmission measurement

(85) S2.2 Collimation

(86) S2.3 Detecting or setting the sample partitioning

(87) S2.4 Displacing/positioning the sample, in particular by translation and/or rotation

(88) S3 Third step, in particular detecting/measuring emitted gamma radiation and evaluating measured gamma radiation

(89) S3.1 Detecting/measuring gamma radiation or evaluating the gamma spectrum

(90) S3.2 Element/peak identification

(91) S3.3 Interference analysis

(92) S3.4 Evaluation of peaks, in particular in respect of peak area and background

(93) S4 Fourth step, in particular evaluating measured gamma radiation

(94) S4.1 Evaluating interactions within the sample

(95) S4.2 Evaluating interactions in the detector

(96) S4.3 Determining the solid angle between sample and detector

(97) S4.4 Determining photopeak efficiencies, in particular initial photopeak efficiencies

(98) S5 Fifth step, in particular determining at least one element, in particular the mass

(99) S5.1 Determining at least one elemental mass or elemental mass ratios

(100) S5.2 Determining at least one cross section

(101) S6 Sixth step, in particular calculating the neutronics

(102) S6.1 Evaluating interactions within the sample

(103) S6.2 Evaluating a neutron spectrum

(104) S6.3 Evaluating a neutron flux

(105) v1 First variable/parameter, in particular able to be input manually, in particular neutron source strength

(106) v2 Second variable/parameter, in particular able to be input manually, in particular sample geometry

(107) v3 Third variable/parameter, in particular able to be input manually, in particular sample mass

(108) x Longitudinal axis

(109) y Transverse axis

(110) z Vertical axis