EP0102398A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Method and apparatus for the detection of neutrinos and uses of the neutrino detector
Assignee: Drukier Andrzej Kamil
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Filing: 1982-08-09
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Granted: —
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Expires: 2002-08-09
Abstract
Abstract Neutrinos are detected by allowing them to scatter on nuclei contained in a detector and by detecting the recoil of the nuclei. Because the probability of a neutrino being scattered is very low the probability is very high that a neutrino will only cause recoil of a single nucleus. On the other hand background radiation is likely to cause the recoil of a large number of electrons and/or nuclei so that neutrino scattering can be detected by distinguishing between the recoil of a single nucleus and the simultaneous recoil of a plurality of electrons/nuclei. In one form of the detector the nuclei are present as minute superconducting metal grains which are held in the superconducting state. At low temperatures the grains have a very low specific heat and the scattering of a neutrino will cause a single grain to heat up and change from the superconducting to the normal conducting state. This change will result in a perturbation of an applied magnetic field, as a result of the Meissner effect, and the perturbation of the magnetic field can be detected, for example as an e.m.f. induced in a detector loop. Several different superconducting arrangements are described. A semiconductor arrangement for detecting nuclear recoil is also described. The neutrino detector can be used, amongst other things, for monitoring reactor activity and for prospecting for subterranean deposits of radioactive elements, minerals found in association with these elements, and oil and gas.
Inventors
- 👤 Andrzej Kamil Drukier
- 👤 Leo Stodolsky
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-02 23:37
CPC Classifications
G; G01; G01T; G01T1/00; G01T1/16; G01T1/1606; Y; Y10; Y10S; Y10S376/00; Y10S376/913
Claims Analysis
Total Claims: 39
Claim 1
Independent Claim
25 words
A method of detecting neutrinos comprising the steps of scattering the neutrinos on nuclei contained in a detector and detecting the recoil of said nuclei.
Claim 2
Independent Claim
25 words
A method of detecting neutrinos comprising the steps of scattering the neutrinos on nuclei contained in a detector and detecting the recoil of said nuclei.
Claim 3
Dependent Claim
29 words
A method in accordance with claim 1 and wherein said nuclear recoil is detected by measuring an associated signal representative of perturbation of the quiescent state of the detector.
Claim 4
Dependent Claim
56 words
A method in accordance with claim 2 and comprising the further steps of analysing the measured nuclear recoil to distinguish between the recoil of a single nucleus and other types of interactions involving recoil of a plurality of electrons and/or nuclei and accepting the signal as a neutrino count only when a single nucleus has recoiled.
Claim 5
Dependent Claim
35 words
A method in accordance with claim 3 wherein said detector is considered as a plurality of volumes and wherein said neutrino count is updated only when a single nucleus in the associated volume has recoiled.
Claim 6
Independent Claim
59 words
A method in accordance with any one of the preceding claims 1 to 3 wherein said nuclei are present in the form of the nuclei of a plurality of superconducting metal elements and wherein the step of detecting the nuclear recoil is effected by detecting the heating and subsequent change of state of one of the superconducting metal elements.
Claim 7
Dependent Claim
61 words
A method in accordance with claim 5 wherein said superconducting elements are not in a superheated state and comprising the further steps of detecting the time required for said superconducting metal element to change back to the superconducting state, comparing this time with a characteristic time range and accepting the neutrino count only when said time falls within said time range.
Claim 8
Independent Claim
93 words
A method in accordance with either of claims 5 or 6 wherein said superconducting metal elements each have at least one dimension which is very small and are distributed in a plurality of volumes, and wherein at least one relatively massive superconducting metal body is present in each volume, the method further comprising the steps of detecting changes of state of said relatively massive superconducting metal bodies as a measure of local temperature instability in the associated volume and rejecting other signals originating from the associated volume during the period of temperature instability.
Claim 9
Independent Claim
83 words
A method in accordance with any one of the preceding claims 5 to 7 and wherein the step of detecting the change of state of the superconducting metal elements is effected by subjecting the metal elements to a magnetic field at the appropriate level and electronically detecting the entry of the magnetic field into the_superconducting elements on the change of state from superconducting to non-superconducting,and/or expulsion of the magnetic field from the superconducting elements on the change of state from non-superconducting to superconducting.
Claim 10
Dependent Claim
25 words
A method in accordance with claim 8 and wherein the level of the magnetic field is selected to determine the energy threshold of the detector.
Claim 11
Independent Claim
36 words
A method in accordance with either one of claims 8 and 9 and wherein the energy deposed is measured by measuring the time required for the superconducting metal element to change back to the superconducting state.
Claim 12
Independent Claim
56 words
A method in accordance with any one of claims 8 to 10 and wherein the entry/expulsion of the magnetic field into/from the superconducting elements is detected by detecting the associated e.m.f. induced into an associated pick-up loop or by detecting the change of the state of polarisation of a monitoring light beam directed through the detector.
Claim 13
Independent Claim
53 words
A method in accordance with any one of the preceding claims 5 to 9 wherein the superconducting metal elements are in the form of thin wires or films and wherein the step of detecting the change of state is effected by monitoring the change of resistivity and/or impedance of the wires or films.
Claim 14
Independent Claim
43 words
A method in accordance with any one of claims 1 to 3 wherein said nuclei are the nuclei of a heavy element based semi-conductor detector and wherein recoil of the nuclei is measured by detecting ionisation resulting from perturbation created by the recoil.
Claim 15
Dependent Claim
96 words
Apparatus for detecting neutrinos, the apparatus comprising a plurality of superconducting metal elements, at least one dimension of which is small, means for cooling said superconducting elements to a temperature at which they are superconducting, means for impressing a magnetic field on said superconducting elements, means for detecting the change of state of said superconducting elements, and means for discriminating between the change of state of just one of said elements and the change of state of a plurality of said elements, and for accepting the neutrino count only when a single element has changed state.
Claim 16
Dependent Claim
96 words
Apparatus for detecting neutrinos, the apparatus comprising a plurality of superconducting metal elements, at least one dimension of which is small, means for cooling said superconducting elements to a temperature at which they are superconducting, means for impressing a magnetic field on said superconducting elements, means for detecting the change of state of said superconducting elements, and means for discriminating between the change of state of just one of said elements and the change of state of a plurality of said elements, and for accepting the neutrino count only when a single element has changed state.
Claim 17
Dependent Claim
35 words
Apparatus in accordance with claim 15 wherein the superconducting elements are formed of a material having a high atomic, number and wherein said material is preferably either an element or an alloy of high purity.
Claim 18
Dependent Claim
42 words
Apparatus in accordance with one of the claims 15 to 18 wherein said superconducting metal elements are in the form of individual grains of superconducting metal disposed in a carrier matrix, said grains preferably being of substantially the same size and composition.
Claim 19
Dependent Claim
57 words
Apparatus in accordance with one of the claims 15 or 16 wherein said superconducting metal elements each comprise a thin sheath of superconducting metal on a core of magnetisable material said core being preferably elongate, if desired in the form of wires, but with =said superconducting metal and said elongate care being preferably formed as thin films.
Claim 20
Dependent Claim
37 words
Apparatus in accordance with preceding claim 17 and wherein said means for detecting the change of state of said superconducting elements comprises means for detecting the change of resistivity thereof which occurs during a change of state.
Claim 21
Dependent Claim
98 words
Apparatus in accordance with any one of the preceding claims 14 to 17 wherein said means for cooling said superconducting elements and said means for impressing a magnetic field on said superconducting elements are arranged to maintain said superconducting elements in the non-metastable superconducting state, and wherein means is provided for determining the time interval between a change of state occurring in one of said superconducting elements and the time required for it to return to its original state, and for comparing this time with a known time range characteristic of the range of neutrino energies of interest.
Claim 22
Dependent Claim
40 words
20 . Apparatus in accordance with any one of the preceding claims 14 to 19 wherein the superconducting elements are considered as a plurality of volumes and wherein each said volume constitutes or is associated with a separate evaluation channel.
Claim 23
Dependent Claim
56 words
Apparatus in accordance with claim 2a and further comprising at least one relatively massive superconducting body in each volume, means for detecting-a change of state of said superconducting body as a measure of temperature instability in that volume, and means for inhibiting the recognition of signals from the associated volume during said period of temperature instability.
Claim 24
Dependent Claim
54 words
Apparatus in accordance with claim 21 wherein the superconducting metal elements are in the form of grains and the superconducting bodies are in the form of grains which are at least ten times larger and are preferably made of material having a change of state temperature threshold lower than that of said superconducting elements.
Claim 25
Dependent Claim
114 words
Apparatus in accordance with any one of the preceding claims 14 to 17 and 19 to 22 wherein said means for detecting the change of state of said superconducting elements and/or bodies comprises a plurality of pick-up loops disposed between said superconducting elements, and means for detecting e.m.f.'s induced in the pick-up loops as a result of said magnetic field being perturbed by a change of state of one of said superconducting elements,and wherein means are preferably provided for comparing the size of said e.m.f.'s with a range of values corresponding to the expected energies deposed by the neutrinos, and for accepting said count only when a measured e.m.f. falls within the expected range.
Claim 26
Dependent Claim
55 words
Apparatus in accordance with any one of said claims 14 to 23 wherein said means for discriminating between the change of state of just one of said elements and the change of state of a plurality of said elements, at least within a specified volume of said elements, comprises a coincidence or delayed coincidence circuit.
Claim 27
Dependent Claim
87 words
Apparatus in accordance with preceding claim 16 wherein said matrix is optically transparent and wherein said means for detecting a change of state of said superconducting elements comprises means for directing a beam of polarised light through said matrix, and means for detecting a change of polarisation in said beam of light due to a perturbation of the magnetic field associated with a change of state of said superconducting element, and wherein, optionally, means is provided for forming a holographic image of the matrix and superconducting elements.
Claim 28
Dependent Claim
26 words
Apparatus in accordance with any one of said claims 15 to 32 wherein said superconductor is selected from metals which do not have long-lived radioactive isotopes.
Claim 29
Dependent Claim
41 words
Apparatus in accordance with any one of the preceding claims 15 to 37 wherein signals representative of the change of state of the individual superconducting elements are in, or converted into, electrical form and are passed to a computer for processing.
Claim 30
Dependent Claim
57 words
Apparatus for detecting neutrinos, the apparatus comprising a semiconductor detector, electrical means for detecting signals from said semiconductor device due to incident radiation, and means for discriminating between signals due to the recoil of a single nucleus in the semiconductor device within an energy range corresponding to the expected energies of the incident neutrinos and other signals.
Claim 31
Dependent Claim
57 words
Apparatus for detecting neutrinos, the apparatus comprising a semiconductor detector, electrical means for detecting signals from said semiconductor device due to incident radiation, and means for discriminating between signals due to the recoil of a single nucleus in the semiconductor device within an energy range corresponding to the expected energies of the incident neutrinos and other signals.
Claim 32
Dependent Claim
101 words
Apparatus according to claim 39 wherein the semiconducting detector consists either of a single crystal with a volume larger than 100 cc or of a collection of crystals having a total volume larger than 100 cc, and wherein said semiconductor device is preferably based on silicon, or germanium (either intrinsic or lithium drifted) or on a compound such as Hg I, Pb I or CdTe of which at least one component has a high atomic number A ≥ 100, said semiconductor device being preferably of high purity, the apparatus preferably further comprising passive and/or active shielding against other types of radiation.
Claim 33
Dependent Claim
102 words
The use of a neutrino detector, in particular a neutrino detector operating in accordance with the method of one of the preceding claims 1 to 13 or a neutrino detector in accordance with one of the preceding claims 14 to 29, for monitoring a nuclear installation such as a reactor and in particular for at least one of the following purposes: for searching for major leaks from fuel elements into the moderator/coolant matrix, for monitoring a reactor following an accident and for assessing changes in the elemental/isotopic composition of fissionable material inside the fuel rods by measurement of the neutrino energy spectrum.
Claim 34
Dependent Claim
49 words
The use of a neutrino detector in accordance with claim 30 wherein the detector is placed outside the reactor confinement but preferably within 100 m of the reactor core and wherein, optionally, the mass of the detector is divided into at least three modules placed around the reactor core.
Claim 35
Dependent Claim
47 words
The use of a neutrino detector in accordance with any one of the preceding claims 30 or 31 wherein the total mass of the detecting material is at least one hundred kilograms and wherein the measured flux of neutrinos is used for dynamic analysis of reactor performance.
Claim 36
Dependent Claim
63 words
The use of a neutrino detector in accordance with any one of the preceding claims 30 to 32 wherein the total mass of the detecting material is larger than 1000 kgs and wherein the detector is either divided into several modules or is arranged for movement around the reactor core for tomographic reconstruction of the location of fission products inside the reactor core.
Claim 37
Dependent Claim
52 words
The use of a neutrino detector, in particular a neutrino detector operating in accordance with the method of one of the preceding claims 1 to 13 or a neutrino detector in accordance with one of the preceding claims 14 to 29 for monitoring installations for the storage and/or processing of radioactive materials.
Claim 38
Dependent Claim
48 words
The use of a neutrino detector, in particular a neutrino detector operating in accordance with the method of claims 1 to 13 or a neutrino detector in accordance with claims 14 to 29, for studying the geological structure of the earth through the neutrino signature of radioactive elements.
Claim 39
Dependent Claim
145 words
The use of a neutrino detector in accordance with claim 35 for at least one of the following purposes:for detecting raw material deposits in the earth, for detecting deposits of one or more of the naturally radioactive elements, in particular K 40, U 238, U 235 and thorium, for detecting raw material resources which are found in association with one or more radioactive elements, for detecting deposits of materials with lower than average neutrino activity, in particular oil, gas and coal deposits and for finding additional deposits of raw materials in existing mines from the neutrino signature of these deposits; wherein the neutrino detector is arranged for movement in mine shafts and tunnels, said neutrino detector being preferably either mounted, towed or suspended for geological prospecting beneath the oceans, seas or lakes or appropriately shielded and transported by a movable vehicle for above ground prospecting.
References Cited (Backward Citations)
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