GB2200984A - Fire optic ionizing radiation detector - Google Patents
Fire optic ionizing radiation detector Download PDFInfo
- Publication number
- GB2200984A GB2200984A GB08630057A GB8630057A GB2200984A GB 2200984 A GB2200984 A GB 2200984A GB 08630057 A GB08630057 A GB 08630057A GB 8630057 A GB8630057 A GB 8630057A GB 2200984 A GB2200984 A GB 2200984A
- Authority
- GB
- United Kingdom
- Prior art keywords
- optical fibre
- microns
- fibre
- light
- core diameter
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 230000005865 ionizing radiation Effects 0.000 title abstract 2
- 239000013307 optical fiber Substances 0.000 claims abstract description 47
- 239000000835 fiber Substances 0.000 claims abstract description 36
- 230000005855 radiation Effects 0.000 claims abstract description 25
- 238000001514 detection method Methods 0.000 claims abstract 4
- 238000005253 cladding Methods 0.000 claims description 11
- 230000003287 optical effect Effects 0.000 claims description 8
- 238000005424 photoluminescence Methods 0.000 claims description 8
- 239000002019 doping agent Substances 0.000 claims description 5
- 239000004065 semiconductor Substances 0.000 claims description 5
- 230000004888 barrier function Effects 0.000 claims 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims 6
- 235000012239 silicon dioxide Nutrition 0.000 claims 4
- 238000002347 injection Methods 0.000 claims 2
- 239000007924 injection Substances 0.000 claims 2
- 238000004891 communication Methods 0.000 abstract description 2
- 238000004020 luminiscence type Methods 0.000 abstract 1
- 238000000034 method Methods 0.000 description 5
- 238000005259 measurement Methods 0.000 description 3
- 238000012544 monitoring process Methods 0.000 description 3
- 239000011162 core material Substances 0.000 description 2
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000002070 germicidal effect Effects 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 230000004431 optic radiations Effects 0.000 description 1
- 238000001959 radiotherapy Methods 0.000 description 1
- 238000009877 rendering Methods 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 230000003595 spectral effect Effects 0.000 description 1
- 238000004659 sterilization and disinfection Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
- G01T1/00—Measuring X-radiation, gamma radiation, corpuscular radiation, or cosmic radiation
- G01T1/16—Measuring radiation intensity
- G01T1/20—Measuring radiation intensity with scintillation detectors
- G01T1/201—Measuring radiation intensity with scintillation detectors using scintillating fibres
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
- G01T1/00—Measuring X-radiation, gamma radiation, corpuscular radiation, or cosmic radiation
- G01T1/02—Dosimeters
- G01T1/06—Glass dosimeters using colour change; including plastic dosimeters
Landscapes
- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Physics & Mathematics (AREA)
- High Energy & Nuclear Physics (AREA)
- Molecular Biology (AREA)
- Spectroscopy & Molecular Physics (AREA)
- Measurement Of Radiation (AREA)
Abstract
The ionizing radiation detector comprises an optical fibre, and a detection system 14 to sense radiation induced luminescence emitted from both ends of the fibre. The optical fibre can be spooled, to provide a discrete detector or the optical fibre can be installed around an area to provide an integrated detector. To calibrate the fibre to allow for radiation induced increase of attenuation, a second, identical, optical fibre is subjected to the same environment and its attenuation is measured between source 16 and detector 15. A third detector 18 may monitor the output of source 16. The fire may be similar to a conventional optreal communication fibre having a core surrounded by a sheath of lower refractive index. <IMAGE>
Description
FIBRE OPTIC IONISING RADIATION DETECTOR
Technical Field
This invention relates to a fibre optic radiation detector.
Background
There are many instances where the level of ionising radiation has to be determined. These include industrial and personnel monitoring, hospital X ray and radiotherapy units, and germicidal sterilisation. In some cases the detecting geometry is complex and conventional detectors can only give an approximate measure of the dose rate received by the specimen in question. In applicationsswhere an integrated dose rate measurement is required several or many conventional detectors would be required to cover the area of interest. Their electrical signals are vunerable to corruption by ambient RF,
EMI or magnetic fields present. To determine the radiation dose accumulated by a specimen several or many conventional dosimeters are necessary to integrate the acquired dose received.There is a growing requirement for a single ionising radiation detector to give both a measurement of dose rate and accumulated dose.
When an optical fibre is exposed to ionising radiation, pulses of light are created in the fibre by photoluminescent processes (see M J Marrone, Appl Phys Lett. 38(3) p115) and by other mechanisms. The ionising radiation reacts with trace impurities, dopants within the fibre or with 'as drawn' silicon lattice defects.
Summary of invention
An ionising radiation detector in accordance with the present invention comprises of optical fibres and receivers sensitive to the spectral range of the light produced in the fibre. The optical fibre is the sensor and it is this that produces pulses of light upon irradiation.
Detailed description
The ionising radiation detector presented here uses an optical fibre, see Fig 1, as the detecting medium. It is expected that the optical fibre used will be similar to those currently used for data communication purposes and have a core region 10 and a cladding 11 of lower refractive index. The ionising radiation will react with the core material and produce light pulses due to photoluminescent and other processes. It is expected that the optical fibre will be sheathed in commercially available cable types. These cable types could increase the sensitivity of the proposed detector due to the incident radiation ejecting Compton electrons into the optical fibre or by other secondary processes.
The detector will consist of two identical fibre cable types 12 and 13 in Fig 2 each containing the same number of identical optical fibres (shown wound on a drum 19). The photoluminescence produced in 12 will travel to both ends of the optical fibre confined by the law of optics where its level will be measured by a photomultiplier tube, avalanche photodiode or a pin photodiode denoted 14 in Fig 2. The second fibre 13 is used to provide continuous self calibration because as fibre 12 acquires a dose history ie. the accumulated dose increases, the optical attenuation of the fibre(s) also increases thus rendering the correlation of dose rate to received light level meaningless.
Fibre 13 will receive the same radiation dose as that of fibre 12 and hence its optical attenuation will increase at the same rate. Under irradiation conditions photoluminescence will also be produced in fibre 13 tut only half will be sensed by the receiver denoted 15 in Fig 2. By injecting light (from a semiconductor light emitting diode or a semi-coductor laser diode) of the same wavelength as the photoluminescence into the other end of fibre 13 (at point 16) until the light level sensed by receiver 15 equals that sensed by receiver 14, then it is a simple matter to calculate the attenuation of the fibre. The level of light injected into the fibre at.point 16 can be derived either by monitoring the current through the light source or by using a fibre coupler 17 and a third receiver denoted 18 in Fig 2.If the first method is to be used then the fibre coupler 17 could be ommitted. Having derived the power level of light injected into the fibre at point 16 (say numerically, p) and by using the light level sensed by receiver 14 (say numerically, n) then the attenation of the fibre 12 to photoluminescence or light produced by any other processes at any point along the fibres' length would be ;
log e (2p/n)
1 - (n/2p)
Therefore the total amount of light generated in fibre 12 will be n multiplied by the attenuation factor given above. Since the total light generated is related to the dose rate the latter is therefore derived.
The proposed detector can simultaneously to the above, give a measure of the total acquired radiation dose or the acquired radiation dose from some arbitary time (specified as t). There is a relationship between total acquired radiation dose and the optical attenuation of the fibre. During the determination of radiation dose rate the optical attenuation is calculated as detailed above. This quantity is then used to determine the acquired radiation dose. Or by subtracting the previous acquired radiation dose measurement (at time t) from the current one, the radiation dose acquired since time t can be calculated.
Fig 2 shows the two fibre cables wound on a drum 19. This drum would then represent the ionising irradiation detector and be placed in the area whose radiation field was to be measured. Thelength of fibre cable 12 and 13 could be many metres long thus allowing remote monitoring. Since the photons travelling down the fibre possess no charge they can not be interfered with by
RF, EMI or magnetic fields hence there will be no 'pick up' on any part of the fibre. As a detecting element the fibre cable need not be wound on a spool but could be wrapped, draped, hung or configured into the required geometry.
Claims (47)
- We claim, 1. Apparatus for determining the level of incident ionising radiation comprises of: Two lengths of optical fibres which may be individually sheathed or sheathed together.A detection system to sense the photoluminescence emitting from both ends of fibre 12.A system to inject light into fibre 13 at point 16.A system to determine the power level of the light injected at point 16.A detection system to sense the light emitting from fibre 13.
- 2. Apparatus as claimed in claim 1 in which the optical fibre has a core diameter of 50 microns.
- 3. Apparatus as claimed in claim 1 in which the optical fibre has a core diameter of 62.5 microns.
- 4. Apparatus as claimed in claim 1 in which the optical fibre has a core diameter of 85 microns.
- 5. Apparatus as claimed in claim 1 in which the optical fibre has a core diameter of 100 microns.
- 6. Apparatus as claimed in claim 1 in which the optical fibre has a core diameter of 200 microns.
- 7. Apparatus as claimed in claim 1 in which the optical fibre has a core diameter in the range 200 microns to 1000 microns.
- 8. Optical fibre as claimed in claims 2, 3, 4, 5, 6 and 7 that has a core region whose refractive index has been modified using dopants.
- 9. Optical fibre as claimed in claims 2, 3, 4, 5, 6 and 7 that has a core region composed of pure silica.
- 10. Apparatus as claimed in claim 1 in which the optical fibre has a cladding diameter of 125 microns.
- 11. Apparatus as claimed in claim 1 in which the optical fibre has a cladding diameter of 140 microns.
- 12. Apparatus as claimed in claim 1 in which the optical fibre has a cladding diameter in the range 140 microns to 1500 microns.
- 13. Optical fibre as claimed in claims 11 and 12 that has a cladding region whose refractive index has been modified using dopants.
- 14. Optical fibre as claimed in claims 11 and 12 that has a cladding region composed of pure silica.
- 15. Apparatus as claimed in claim 1 in which the optical fibre is only secondarily coated.
- 16. Apparatus as claimed in claim 1 in which the optical fibre has no ruggedised covering.
- 17. Apparatus as claimed in claim 1 in which the optical fibre cable has a water barrier configuration.
- 18. Fibre optic cable as claimed in claim 17 which has a metallic water barrier.
- 19. Fibre optic cable as claimed in claim 17 which has a non metallic water barrier.
- 20. Apparatus for determining the total acquired radiation dose would comprise of: Two lengths of optical fibre which may be individually sheathed or sheathed together.A system to inject light into fibre 13 at point 16.A system to determine the power level of the light injected at point 16.A detection system to sense the light emitting from fibre 13.
- 21. Apparatus as claimed in claim 20 in which the optical fibre has a core diameter of 50 microns.
- 22. Apparatus as claimed in claim 20 in which the optical fibre has a core diameter of 62.5 microns.
- 23. Apparatus as claimed in claim 20 in which the optical fibre has a core diameter of 85 microns.
- 24. Apparatus as claimed in claim 20 in which the optical fibre has a core diameter of 100 microns.
- 25. Apparatus as claimed in claim 20 in which the optical fibre has a core diameter of 200 microns.
- 26. Apparatus as claimed in claim 20 in which the optical fibre has a core diameter in the range 200 microns to 1000 microns.
- 27. Optical fibre as claimed in claims 21, 22, 23, 24, 25 and 26 that has a core region whose refractive index has been modified using dopants.
- 28. Optical fibre as claimed in claims 21, 22, 23, 24, 25 and 26 that has a core region composed of pure silica.
- 29. Apparatus as claimed in claim 20 in which the optical fibre has a cladding diameter of 125 microns.
- 30. Apparatus as claimed in claim 20 in which the optical fibre has a cladding diameter of 140 microns.
- 31. Apparatus as claimed in claim 20 in which the optical fibre has a cladding diameter in the range 140 microns to 1500 microns.
- 32. Optical fibre as claimed in claims 30 and 31 that has a cladding region whose refractive index has been modified using dopants.
- 33. Optical fibre as claimed in claims 30 and 31 that has a cladding region composed of pure silica.
- 34. Apparatus as claimed in claim 20 in which the optical fibre is only secondarily coated.
- 35. Apparatus as claimed in claim 20 in which the optical fibre has no ruggedised covering.
- 36. Apparatus as claimed in claim 20 in which the optical fibre cable has a water barrier configuration.
- 37. Optical fibre cable as claimed in claim 36 which has a metallic water barrier.
- 38. Optical fibre cable as claimed in claim 36 which has a non metallic water barrier.
- 39. Apparatus as claimed in claims 1 and 20 in which the light and photoluminescence detectors are semi conductor pin diodes.
- 40. Apparatus as claimed in claim 1 knd Q in whiah tk light and photoluminescence detectors are semi conductor avalanche photo diodes
- 41. Apparatus as claimed in claims 1 and 20 in which the light and photoluminescence detectors are photomultiplier tubes.
- 42. Apparatus as claimed in claims 1 and 20 in which the light injection device is a semi conductor LED.
- 43. Apparatus as claimed in claims 1 and 20 in which the light injection device is a semi conductor laser diode.
- 44. Apparatus as claimed in claims 1 and 20 in which the optical fibres are up to five-kilometres in length.
- 45. Apparatus as claimed in claim 1 in which the level of incident radiation is calculated and displayed by appropriate electronic means.
- 46. Apparatus as claimed in claim 20 in which the level of acquired radiation dose is calculated and displayed by appropriate electronic means.
- 47. Apparatus as claimed in claims 1 and 20 in which the optical fibre cable has a metallic armoured structure.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8630057A GB2200984B (en) | 1986-12-16 | 1986-12-16 | Fibre optic ionising radiation detector |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8630057A GB2200984B (en) | 1986-12-16 | 1986-12-16 | Fibre optic ionising radiation detector |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB8630057D0 GB8630057D0 (en) | 1987-01-28 |
| GB2200984A true GB2200984A (en) | 1988-08-17 |
| GB2200984B GB2200984B (en) | 1990-11-07 |
Family
ID=10609102
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8630057A Expired - Lifetime GB2200984B (en) | 1986-12-16 | 1986-12-16 | Fibre optic ionising radiation detector |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2200984B (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3929294A1 (en) * | 1989-09-04 | 1991-03-14 | Forschungszentrum Juelich Gmbh | METHOD AND MEASURING DEVICE FOR MEASURING THE DOSAGE OR DOSAGE PERFORMANCE OF CORE RADIATION |
| WO1997005506A1 (en) * | 1995-08-01 | 1997-02-13 | Forschungszentrum Jülich GmbH | Process and device for measuring the radiation depth of radiation |
| WO1997021112A3 (en) * | 1995-12-02 | 1997-08-21 | Forschungszentrum Juelich Gmbh | Sensor for measuring a tissue equivalent radiation dose |
| FR2775085A1 (en) * | 1998-02-19 | 1999-08-20 | Nauchny Ts Volokonnoi Optikipr | Ionizing radiation dose measuring procedure and optical fiber detector |
| EP0851242A3 (en) * | 1996-12-27 | 2002-01-30 | Mitsubishi Denki Kabushiki Kaisha | Radiation detector using scintillation fibers |
| WO2011146236A3 (en) * | 2010-05-19 | 2012-04-26 | Raytheon Company | Detection of kr-85 gamma rays for positive verification of mass in pressurized bottles |
| WO2014161732A1 (en) * | 2013-04-04 | 2014-10-09 | Cern - European Organization For Nuclear Research | Apparatus and method for determining a dose of ionizing radiation |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4413184A (en) * | 1981-05-11 | 1983-11-01 | The United States Of America As Represented By The Secretary Of The Navy | Optical fiber radiation detector and real-time dosimeter |
-
1986
- 1986-12-16 GB GB8630057A patent/GB2200984B/en not_active Expired - Lifetime
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4413184A (en) * | 1981-05-11 | 1983-11-01 | The United States Of America As Represented By The Secretary Of The Navy | Optical fiber radiation detector and real-time dosimeter |
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3929294A1 (en) * | 1989-09-04 | 1991-03-14 | Forschungszentrum Juelich Gmbh | METHOD AND MEASURING DEVICE FOR MEASURING THE DOSAGE OR DOSAGE PERFORMANCE OF CORE RADIATION |
| WO1997005506A1 (en) * | 1995-08-01 | 1997-02-13 | Forschungszentrum Jülich GmbH | Process and device for measuring the radiation depth of radiation |
| US6087664A (en) * | 1995-08-01 | 2000-07-11 | Forschungszentrum Julich Gmbh | Process and device for measuring the radiation depth of radiation |
| WO1997021112A3 (en) * | 1995-12-02 | 1997-08-21 | Forschungszentrum Juelich Gmbh | Sensor for measuring a tissue equivalent radiation dose |
| US6041150A (en) * | 1995-12-02 | 2000-03-21 | Forschungszentrum Julich Gmbh | Multipass cavity sensor for measuring a tissue-equivalent radiation dose |
| EP0851242A3 (en) * | 1996-12-27 | 2002-01-30 | Mitsubishi Denki Kabushiki Kaisha | Radiation detector using scintillation fibers |
| FR2775085A1 (en) * | 1998-02-19 | 1999-08-20 | Nauchny Ts Volokonnoi Optikipr | Ionizing radiation dose measuring procedure and optical fiber detector |
| BE1014384A3 (en) * | 1998-02-19 | 2003-10-07 | Nauchny Ts Volokonnoi Optiki P | Method for determining the dose of ionizing radiation and sensor fiber optic (realization of its versions) |
| WO2011146236A3 (en) * | 2010-05-19 | 2012-04-26 | Raytheon Company | Detection of kr-85 gamma rays for positive verification of mass in pressurized bottles |
| WO2014161732A1 (en) * | 2013-04-04 | 2014-10-09 | Cern - European Organization For Nuclear Research | Apparatus and method for determining a dose of ionizing radiation |
Also Published As
| Publication number | Publication date |
|---|---|
| GB8630057D0 (en) | 1987-01-28 |
| GB2200984B (en) | 1990-11-07 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 19931216 |