CN1032790C - Polariged beam magnetic deflection laser isotope liquid concentration device - Google Patents
Polariged beam magnetic deflection laser isotope liquid concentration device Download PDFInfo
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- CN1032790C CN1032790C CN 92110508 CN92110508A CN1032790C CN 1032790 C CN1032790 C CN 1032790C CN 92110508 CN92110508 CN 92110508 CN 92110508 A CN92110508 A CN 92110508A CN 1032790 C CN1032790 C CN 1032790C
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Abstract
The present invention relates to a polarized-beam magnetic-deflection laser isotope liquid concentrating device which is a device for concentrating isotopes through laser pumping and a rotary state selecting magnet. The present invention is composed of an atom beam polarizing deflector composed of a beam source chamber, an atom and laser acting chamber, a state selecting magnet, a detector and a collector, and a corresponding laser source. Atom beams generate action with laser beams with vertical incidence in a weak-orientation magnetic field so that atoms with different isotopes form atom beams polarized along different directions through selective optical pumping. After atom beams pass through the state selecting magnet, isotopes not required are deflected, and required isotopes are collected after being focused. The abundance of the isotopes is enhanced 1.4 to 3.2 times higher than the natural abundance. The present invention has the advantage of simple device, and is a concentration method with application value and a device capable of being adopted in industries.
Description
Polariged beam magnetic deflection laser isotope liquid concentration device is that a kind of laser pumping technology and spin state selection magnet used focuses on principle with deflection, equipment to realize that isotope concentrates belongs to and utilizes laser instrument with state selection magnet atomic beam to be polarized and the experimental provision that separates.It can be scientific research, national defence, medical treatment, the energy, environmental protection and industrial and agricultural production cheap enriched isotope is provided.
Along with the development of laser application technique, the design and the method for various laser isotope separations are arisen at the historic moment.They are: (1) selection chemical reaction method.The existing long history of this method, as far back as nineteen sixty-eight, Tiffany has carried out the trial first (W.B.GIFfanyJ.Chem.Phys.48,3019 (1968)) of photochemistry isotopic separation with laser.Because in chemical reaction process, the isotope selectivity is difficult to keep, thereby can not be used for industrial production.(2), selective laser ionization.Early seventies, (V.S.Letokhov, Soviet patentN65743,30March, 1970 such as the Letokhkv of the Soviet Union; R.V.Ambartzumian, V.P.KalininandV.S.Letokhov, Pisma Zh.eksp.iteor.fiz.13,305 (1971)) Janes of the U.S. and Levy etc., (G.S.Janes, I.Itzkan, C.T.Pike, R.H.LevyandLiLevin, IEEEJ.QE12,111 (1976)) independently propose to utilize isotope shift simultaneously, by two steps or three step selective excitations, a kind of isotope is ionized, has realized separating of rubidium and uranium by electric deflection then.Afterwards, the Lawrence Livermore National Laboratory of the U.S. carries out the laboratory pilot scale and the research of uranium enrichment with the method, and late nineteen eighties has built up pilot plant.This method has very high specification requirement to used laser instrument, as high pulse energy (1 Jiao Er), narrow pulse width (20～200ns), high repetition frequency (100kHz) and narrow bandwidth (1～3GHZ), laser frequency should be adjustable and have very high stability (± 30MHZ), also need to solve a series of key technology simultaneously.(3), the selectivity molecular photodissociation from and isomerization.In the seventies, the Soviet Union (R.V.Ambartzumian, Yu.A.Gorokhov, V.S.LotokhovandG.N.Makurov, JETP Lett, 21,171 (1975)) and the U.S. (J.J.Lyman, R.J.Jensen, J.Rlnk, C.P.Robinson andS.D.Rockwood, Appl, phys, Lett, two small components of 27,87 (1975) adopt strong infrared laser that molecule is carried out the selectivity multiphoton dissociation respectively, have finished the isotopic separation of sulphur.Afterwards, carried out purpose again and be a large amount of explorations that uranium separates, because the restriction of light source also has very big distance with the production phase.Polyatomic molecule except that dissociating, has also been carried out causing isomerization and the trial of separated isotopes by optical excitation.(4) selective light deflection is changeed.The variation of the specific isotope atom direction of motion that it directly causes by laser has proposed conception (A.Ashkin, Phys.Rev, Lett, 24,156 (1970) to realize isotopic separation as far back as early seventies; 25,1231 (1970) and test (A.Bernbardt, D.Duerre, J.SimpsonandL.Wood, IEEEE J.QE10,789 (1974), but still stay in laboratory stage.1984, the inventor proposes to utilize the laser selective pumping to produce the electron-spin polarization atomic beam, make it deflection in non-uniform magnetic-field, thereby realize isotopic separation (" magnetic deflection by the polarized atom bundle realizes LASER ISOTOPE " Zhu Xiwen, 1605 pages of " Acta Physica Sinica " 33 11 phases of volume).
In order further to verify novelty of the present invention, once Chinese invention patent and utility model patent classified abstract were consulted, approximate with it the or identical patented technology of invention.
Because the huge potential industrial value of laser isotope separation is paid much attention to and be subjected to people, it is reported that more existing schemes are constantly improving and developing to practical direction, but still be in the laboratory research, and do not enter the practical stage.
Obviously, seeking a kind ofly to utilize the laser selective pumping to produce the electron-spin polarization atomic beam, and make it deflection in non-uniform magnetic-field, realize the device that isotope concentrates, is exactly purpose of the present invention.
A kind of technical scheme design that can achieve the above object is as follows: will contain multiple isotopic element and be placed in the electron gun chamber, after heating, the multiple isotopic element in the chamber becomes high-temperature vapour.The atomic beam that releases by specific osculum enters the active region.The direction of atomic beam and beam direction are perpendicular in this active region, selected one or more under certain technical conditions (comprising wavelength selected, polarization, power, live width, incidence angle and beam cross section etc.), the laser source system of running, and the beam direction that produces is parallel with the magnetic direction of active region.Atomic beam is obtained different polarization by the laser beam pumping of vertical incidence in the active region, promptly need the isotope atom positive polarization that concentrates, and other isotope atom negative polarization preferably makes their perfact polarizations.In order to guarantee that the formed polarized state of atom is constant in the laser pumping district, require from pumping area to the high-intensity magnetic field district, the direction and the numerical value change of magnetosonic are slow, and atomic beam satisfies thermal insulation in this zone and gets over condition like this.Under the effect of state selection magnetic field, the isotope atom of positive polarization focuses on the back and arrives gatherer, the collection of quilt.The isotope atom of negative polarization then is deflected, and can not enter in the gatherer, thereby finish isotopic concentrating.
As seen this Design of device guiding theory is how to improve the polarizability and the needed isotopic enrichment of atom.In order to make the atom high degree of polarization, the one, improve pumping rate and increase interaction time of atom and laser, the 2nd, reduce the depolarisation effect that causes because of mixed attitude in collision and the magnetic field.In view of this, in order to obtain the atomic beam of high degree of polarization, except that reducing depolarisation effect, should make also that to have friction speed in the atomic beam all polarized with the atom that is in different hyperfine energy levels.Manage to make it to get over mode again and enter state selection magnetic field, the isotope by this magnetic field is effectively separated by thermal insulation.Therefore the specific requirement to this contrive equipment is:
(1) speed covers completely, and this can make atomic beam collimation, laser beam perpendicular and utilize power broadening to realize with the atomic beam strictness.
(2) hyperfine energy level covers, and can adopt multi-station laser usually.And, then can use wideband laser to having only less hyperfine atom that can the utmost point, or acousto-optic modulator, or become the different angles of cut with atomic beam with the different light beams of same narrow band laser, can distinguish the jump frequency of the different hyperfine energy levels of correspondence like this.But because the dobla frequency displacement, the non-normal incidence light beam can not reach good speed and cover.
(3) enough laser intensity.The raising of laser intensity will increase pumping speed and speed coverage.
(4) the sufficiently long interaction time.But this makes laser and atom repeatedly be used for realizing by extensible beam or by reciprocal folded light beam.According to required concentrated isotope, choose the laser instrument and the light path that adapt with design parameter, make the cross section of optical maser wavelength, polarization, incidence angle, power, bandwidth and light beam satisfy above-mentioned requirements, need the concentrated complete positive polarization of isotope atom like this, the complete negative polarization of other isotope atoms, and the polarized state that keeps being obtained enters state selection magnetic field.
(5) state selection magnet and magnetic field should have certain length and enough magnetic field gradients.
The invention will be further described below in conjunction with embodiment.
Fig. 1 is that a kind of being used for concentrates
6The structural representation of the Polariged beam magnetic deflection laser isotope liquid concentration device of Li.Wherein: 1-argon ion laser is used for the pumping dye laser.Can select 171 argon ion lasers for use, its operation wavelength 514.5nm, power 4W.2,3-single mode ring dye laser is used for the pumping atomic beam, to obtain different polarization.Can select the 380D ring dye laser for use, its operation wavelength 670.8nm, power 100mw, bandwidth 1MHz.4,5-partially reflecting mirror is decomposed into folded light beam and transmitted light beam with incident beam.6-completely reflecting mirror all reflexes to wavemeter with incident beam.7-F-P scanning interferometer is used to monitor the laser works wavelength, and its free spectrum journey is 2GHz.8-wavemeter is used to measure the laser works wavelength, resolution ratio 10
-3Nm.9-linear polarizer makes the laser rays polarization, linear polarization degree＞98%.10-quarter wave plate makes laser circular polarization, circular polarization＞95%.11-diaphragm is used for changing light and atomic beam action time.12-atomic pile is made with stainless steel, and its structure as shown in Figure 2.Place the natural lithium metal in the stove, respectively body of heater and fire door are heated with two groups of heater strips, the firehole diameter is 0.8mm, generally make the fire door temperature higher slightly than furnace body temperature, in order to avoid fire door stops up, furnace temperature is measured by nickel aluminium Nickel-Silicom thermocouple, and furnace body temperature is adjustable, its temperature range: 400 ℃～700 ℃.13-atomic beam collimation aperture is used to collimate atomic beam, and electron gun chamber and interaction chamber are separated aperture 3mm.14-field coil, this field coil center is the laser pumping district.Providing magnetic field intensity in this district is 1 * 10
-4～1 * 10
-3The adjustable alignment magnetic field of T is to form the quantization direction of atom.15-sextupole state selection magnet.Magnetic field intensity is heterogeneous, and magnetic field gradient is 5T/cm, and magnetic pole place maximum magnetic field strength is 0.6T, and the magnetic gap diameter is 2.2mm, long 87mm.Because the result of six pole magnet state selection the isotope atom of negative polarization is deflected, and the isotope atom of positive polarization is focused, collect through being collected device behind the detector.16-hotline detector (or quadrupole mass spectrometer or fluorescence detector).Tungsten filament electric current 1.2A is used to measure the isotopic abundance in concentrated back.17-gatherer is made by glass or quartz, is used to collect concentrated back isotope product.The axis of gatherer should be coaxial with atomic beam.18, two groups of mechanical pumps of 19--oil diffusion pump system, respectively to the atomic beam chamber, active region and detecting chamber vacuumize, and make their vacuum reach 7 * 10 respectively
-3Pa and 3 * 10
-4Pa.The 20-laser window, its residing plane and laser beam intersect with Brewster's angle, and this angle of cut and operation wavelength, component materials are relevant, the angle of cut of 57 ° of selections in the present embodiment.
Fig. 2 is the atomic pile structure that can constitute one type of electron gun chamber.21-fire door heater strip wherein.22-body of heater heater strip.23-fire door, i.e. atomic beam outlet.24-body of heater.25-tantalum diaphragm seal.26-sealing flange.27-furnace charge can be selected the native metal lithium for use.
Fig. 3 is the sectional view of sextupole state selection magnet.Wherein: 28-magnetic pole, make by ingot iron.29-magnet steel can be selected the AINiCo8 permanent-magnet alloy for use.Diameter of bore 2.2mm.Long 87mm.
As seen, each parts are provided with in certain sequence in the atomic beam polarization deflector.And, obtain concentrated effect preferably in order to make this device, the distance in the device between each parts and have related parameter to choose by following criterion:
(1) between atom fire door 23 and the atomic beam collimation aperture 13 distance be 360mm, make it with the aperture diameter ratio be 120: 1.
(2) atomic beam collimation aperture 13 and laser pumping zone centerline (being the optical axis of laser beam) distance range: 30～50mm.
(3) laser pumping zone centerline and sextupole state selection magnet porch distance is 200～300mm, is getted under the condition satisfying thermal insulation by pumping after-polarization atomic beam guaranteeing, carries out the transition to high-intensity magnetic field lentamente from low-intensity magnetic field, to keep the polarized state after the pumping.
(4) sextupole state selection magnet outlet is about 200 millimeters apart with detector, to reduce and to avoid the interference of high-intensity magnetic field to detector.
Present embodiment is for concentrating
6The Li isotope designs, if concentrate the isotope of other element, only need and select for use atomic pile, laser instrument and light path otherwise designed, and other parts then needn't be changed.
The experiment proved that said apparatus compared with prior art has following advantage:
1. can obtain higher concentrated effect.As
6The abundance of Li brings up to 24% by 7.5%,
85The abundance of Rb brings up to 98% by 72%,
87The Rb abundance brings up to 83% by 28%.
2. only need understand a spot of information such as the ground state of isotope atom and indivedual excited state energy level structures.
3. required laser intensity is low far beyond other scheme, as the pumping laser power density that is used to produce polarization only needs tens mw/cm
2
4. magnetic deflection isolation technics scheme is simple, easily implements.
The present invention provides effective method and low cost equipment for the isotope concentration technique.It is reported during nineteen sixty to 1985 year that the whole world is about 80,000,000,000 dollars of resulting accumulation economic benefit aspect the commercial Application of isotope and radiotechnology only.Certainly, the developing in market and the raising of benefit depend on a large amount of, cheap isotopic obtaining.
Claims (8)
1, a kind of Polariged beam magnetic deflection laser isotope liquid concentration device comprises atomic beam polarization, deflector and LASER Light Source, it is characterized in that:
Parts in I, atomic beam polarization, the deflector are arranged in the following order: atomic pile (12), atomic beam collimation aperture (13), field coil (14) state selection magnet (15), detector (16) and gatherer (17),
II, laser source system be by laser instrument (1), (2) and (3), partially reflecting mirror (4), and linear polarizer (9), quarter wave plate (10) and diaphragm (11) constitute, and the central shaft of the atomic beam in the optical axis of LASER Light Source and the atomic beam polarization deflector is perpendicular.
2, Polariged beam magnetic deflection laser isotope liquid concentration device according to claim 1, an end that it is characterized in that having a firehole and be placed in the atomic beam polarization deflector with the atomic pile (12) of calandria.
3, Polariged beam magnetic deflection laser isotope liquid concentration device according to claim 1 and 2 is characterized in that on the axis outside the firehole of atomic pile (12), is provided with an atomic beam collimation aperture (13).
4, Polariged beam magnetic deflection laser isotope liquid concentration device according to claim 1, it is characterized in that on the opposing party's of atomic beam collimation aperture (13) axis, being provided with a field coil (14), one laser window (20) is respectively arranged in the coil both sides, and residing plane of two laser windows and laser beam intersect with Brewster's angle.
5, Polariged beam magnetic deflection laser isotope liquid concentration device according to claim 1 and 2, it is characterized in that on the perpendicular direction of the optical axis of the opposing party of field coil (14) and LASER Light Source, being provided with multipole state selection magnet heterogeneous (15), its magnetic field gradient is 5T/cm, and magnetic pole place maximum magnetic field strength is 0.6T.
6, Polariged beam magnetic deflection laser isotope liquid concentration device according to claim 1 and 2 is characterized in that being provided with detector (16) the opposing party of state selection magnet (15), and the center of its center and atomic beam coincides.
7, polarized beam magnetic according to claim 1 and 2 is compiled changes the LASER ISOTOPE device, it is characterized in that being provided with gatherer (17) the opposing party of detector (16), and its axis and atomic beam axis coincide.
8, according to claim 1 or 4 described Polariged beam magnetic deflection laser isotope liquid concentration devices, it is characterized in that outside laser window (20), on the perpendicular direction of the central shaft of atomic beam, dispose laser source system, it is by one or more laser instrument (1), (2), (3), partially reflecting mirror (4), (5), linear polarizer (9), quarter wave plate (10), diaphragm (11), completely reflecting mirror (6), scanning interferometer (7), wavemeter (8) constitutes, and it is crossing with Brewster's angle with the residing plane of laser window that this laser source system is injected the laser beam of atomic beam polarization deflector.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 92110508 CN1032790C (en) | 1992-09-08 | 1992-09-08 | Polariged beam magnetic deflection laser isotope liquid concentration device |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 92110508 CN1032790C (en) | 1992-09-08 | 1992-09-08 | Polariged beam magnetic deflection laser isotope liquid concentration device |
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| CN1073123A CN1073123A (en) | 1993-06-16 |
| CN1032790C true CN1032790C (en) | 1996-09-18 |
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| CN 92110508 Expired - Fee Related CN1032790C (en) | 1992-09-08 | 1992-09-08 | Polariged beam magnetic deflection laser isotope liquid concentration device |
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| CN101006541B (en) * | 2003-06-02 | 2010-07-07 | 福克斯·彻斯癌症中心 | High energy polyenergetic ion selection systems, ion beam therapy systems, and ion beam treatment centers |
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