Summary of the invention
In view of this, a kind of device and method of spectral measurement provided by the invention, the device and method of the spectral measurementHave the advantages that volume and spectrum drift are small.
For achieving the above object, a technical solution of the present invention is: a kind of device of spectral measurement, packetTop electronics element cell and lower part probe chamber are included, the lower part probe chamber enclosed inside has main detector, main detectionMultiple anticoincidence detectors are arranged in device periphery, and multiple anticoincidence detector outer layer designs have shielded layer；
The shielded layer outer layer design has protective layer, and generator, the generator output end is arranged inside the protective layerIt being connect with electronics element cell, the generator bearing is fixedly connected with two wheels that protective layer front panel bottom surface is arranged,Rotor is fixedly mounted in the bearing middle-end, and magnet is arranged in the rotor radial periphery；
The main detector and anticoincidence detector include scintillation crystal, and shape is posted as cone in the scintillation crystal top surfaceThe optocoupler of body is fit, and photodiode is posted in the side of optocoupler zoarium, the photodiode respectively with spectrum stabilization circuit and inclinedPower circuit connection is set, the spectrum stabilization circuit includes current monitoring part and temperature sensing part, and the current monitoring part is defeatedEnter end to connect with photodiode, the multi-channel analysis circuit connection of current monitoring part output end and electronics element cell,The temperature sensing part monitors scintillation crystal temperature, the multi-channel analysis electricity of temperature sensing part output end and electronics element cellRoad connection, the multi-channel analysis circuit of electronics element cell are connect with bias power supply circuit pressure feedback port.
Preferably, the main detector is cube, and 4 shapes are that the anticoincidence detector of cuboid is mutually spliced to formIntersecting parallels structure.
Preferably, the shielded layer is made of with wolfram steel or lead with wolfram steel double-layer structure fine copper, the protective layer leading flankPull rod is arranged in plate top surface.
Preferably, the scintillation crystal of the main detector uses LaBr3 ︰ Ce crystal or CsI:Tl crystal, the anticoincidenceThe CsI:Tl crystal that the scintillation crystal of detector uses with a thickness of 4cm.
Preferably, the optocoupler zoarium in the main detector and the input terminal of nine photodiodes are connected in parallel, describedOptocoupler zoarium in anticoincidence detector is connect with the input terminal of a photodiode.
Preferably, the photodiode output end is also connect with pre-amplification circuit input terminal, the photodiodeNumber it is identical as the number of pre-amplification circuit, bias power supply circuit.
Preferably, the top electronics element cell top surface is equipped with handle, further include inside the electronics element cell withThe power-switching circuit of rechargeable battery output end connection, and exported by the pre-amplification circuit of line between plate and probe chamberHold the summing circuit of connection, the summing circuit output end connect with anticoincidence circuit, the anticoincidence circuit output end with it is moreTrace analysis circuit connection.
For achieving the above object, another technical solution of the present invention is: providing a kind of spectral measurementThe spectrum stabilization method of device, comprising the following steps:
(1) pass through the reverse leakage current of current monitoring part monitor photodiode；
(2) reverse leakage current monitored is output to multi-channel analysis circuit by current monitoring part；
(3) reverse leakage current finely tunes the output voltage of each bias power supply circuit to multi-channel analysis circuit based on the received, oftenThe input voltage changing value control reverse leakage current average value of a photodiode is consistent；
(4) temperature of temperature sensing part monitoring scintillation crystal, and it is sent to multi-channel analysis circuit；
(5) the multi-channel analysis circuit uses formula according to the temperature information received: y=0.0567x-1.394, meterThe trim values of each bias power supply circuit output voltage are calculated, wherein y is the trim values of bias power supply circuit output voltage, and x isTemperature.
The invention has the following advantages: in the inventive solutions, because substituting light using photodiodeElectric multiplier tube effectively reduces the volume and weight of spectral measurement device as optical read-out device.Meanwhile passing through temperature sensing partDetection scintillation crystal temperature is sent to multi-channel analysis circuit, and temperature information calculates biased electrical to multi-channel analysis circuit based on the receivedThe output voltage of source circuit presses trim values, makes photodiode under different temperatures environment, the pressurization being consistent overcomes wholeThe spectrum of a probe is floated.And the reverse leakage current of every photodiode of current monitoring part monitors, Real-time Feedback trim voltage makeUnder the conditions of different temperatures, different counting rates, average drain currents are consistent every photodiode.Pass through temperature sensing partIt is cooperated with each other with current monitoring part, so that the present invention has the advantages that spectrum drift is small.
Because generator is arranged inside protective layer, the generator bearing and two with the setting of protective layer front panel bottom surfaceA wheel is fixedly connected, and rotor is fixedly mounted in the bearing middle-end.When apparatus of the present invention are mobile, two wheels, which will do it, to be turnedIt is dynamic, and then rotated with dynamic bearing, the rotor on the bearing also can be rotated together and then, and the rotor rotates in magnetSo that magnetic flux is changed and generate induced electromotive force in coil, the induced electromotive force is transmitted to electronics unit by electric wireThe rechargeable battery of room not only solves field charging problems, also saves cost.
Specific embodiment
Following will be combined with the drawings in the embodiments of the present invention, and technical solution in the embodiment of the present invention carries out clear, completeSite preparation description, it is clear that the described embodiment is only a part of the embodiment of the present invention, instead of all the embodiments.Based on thisEmbodiment in invention, every other reality obtained by those of ordinary skill in the art without making creative effortsExample is applied, shall fall within the protection scope of the present invention.
As shown in Figs. 1-2, a kind of device of spectral measurement be upper and lower two parts, including top electronics element cell 3 withAnd lower part probe chamber.3 top surface of top electronics element cell is equipped with handle 4, is packaged with master in the lower part probe chamberDetector 1 and multiple anticoincidence detectors 2, the main detector 1 are the part inside the probe chamber of lower part, under main detector 1End design has window 6, and 1 peripheral part of main detector is then multiple anticoincidence detectors 2, and multiple 2 outer layers of anticoincidence detector are thenFor shielded layer 5,5 outer layer of shielded layer is then protective layer 7, and the 7 front panel top surface of protective layer is provided with pull rod 9, front sideThere are two wheels 8 for the setting of panel bottom surface.
The rechargeable battery of the electronics element cell 3 including rated output 7.2V voltage, the rechargeable battery output end withPower-switching circuit connection, the power-switching circuit include using the booster circuit of Switching Power Supply scheme, reduction voltage circuit and anti-Translation circuit is pressed, the power-switching circuit provides required voltage for each section circuit of the present apparatus.The reduction voltage circuit usesLT3480 chip obtains+3.3V and+5V logic power, and+5V logic power filters acquisition+5V analog power by further,It, which exports electric current, can achieve 2A, and working efficiency can reach 80% or more.The back-pressure translation circuit uses MAX764 chip, andThe circuit output is -5V, it is possible to provide the up to power of 1.5W.The booster circuit use MAX761 chip, output voltage be+12V provides the output electric current of 150mA, and transfer efficiency is up to 90% or so, which also provides battery capacity deficiency detection electricityRoad, cooperated with LED driving circuit provide battery capacity instruction function.Power-switching circuit high conversion efficiency used in the present invention,So that battery life is greater than 9 hours.Electronics element cell 3 further includes summing circuit, anticoincidence circuit and multi-channel analysisCircuit, multiple pre-amplification circuit output ends of line and probe chamber connect respectively between the summing circuit input terminal passes through plateIt connects, the input terminal connection of the summing circuit output end and anticoincidence circuit, the output end and multiple tracks point of the anticoincidence circuitCircuit connection is analysed, the multi-channel analysis circuit is connect with spectrum stabilization circuit and palm display unit respectively.
It is more convenient that the effect of the handle 4 can be such that staff carries, and handle 4 and electronics element cell 3 can be oneStructure, can also be fixed by screw and similar approach is mounted on electronics element cell 3.The shielded layer 5, to take into account machineryPerformance and shield effectiveness, the shielded layer 5 are combined with two layers of wolfram steel with wolfram steel double-layer structure or lead by high purity copper and are formed, and effect isOuter rays are reduced to enter anticoincidence detector 2 and vacation is caused to meet event.The effect of window 6 comes from main detector for detectionThe gamma ray of 1 lower section and natural ray.The protective layer 7 is made of lead material, and environment sheet is effectively reduced in the protective layer 7The radioactive influence in bottom shortens time of measuring under the premise of guaranteeing precision, realizes quickly analysis, and set inside protective layer 7It is equipped with generator, additionally it is possible to charge, solve of the invention when field detects for a long time for the rechargeable battery of electronics element cell 3The charging problems of device.The pull rod 9 has Telescopic, when apparatus of the present invention are mobile, by pull rod 9 from 7 leading flank of protective layerIt is stretched in plate, facilitates dragging.When apparatus of the present invention do not need to be moved, pull rod 9 is zoomed into 7 front panel of protective layerIn.
As shown in Figure 3-4, the bearing 14 for the generator being arranged inside the protective layer 7 is fixedly connected with two wheels 8, instituteIt states 14 middle-end of bearing and is fixedly installed with rotor 13,13 radial outside of rotor is provided with magnet 15.Apparatus of the present invention are in movementWhen, the wheel 8 will do it rotation, and then be rotated with dynamic bearing 14, and the rotor 13 on the bearing 14 can also follow oneRotation is played, the rotor 13 rotates in magnet 15 to be made magnetic flux change and generate induced electromotive force in coil, the senseIt answers electromotive force to be transmitted to the rechargeable battery of electronics element cell 3 by electric wire, charging effect is carried out to the rechargeable battery.This hairThe generator of bright device does not need additional manpower or material resources, can charge to apparatus of the present invention during travelingEffect, not only solves field charging problems, also saves cost.
As shown in figure 5, the main detector 1 includes scintillation crystal 10, optocoupler zoarium 11, light with anticoincidence detector 2Read-out system 12, the optical read-out system 12 include photodiode, spectrum stabilization circuit, pre-amplification circuit and bias supply electricityRoad, and photodiode, spectrum stabilization circuit, pre-amplification circuit and bias power supply circuit are produced on one piece of pcb board.The sudden strain of a musclePost the optocoupler zoarium 11 that the shape that floor space matches with scintillation crystal top area is cone in bright 10 top surface of crystal；Optocoupler is fitPhotodiode is posted in 11 side, and the lateral area of optocoupler zoarium 11 matches with multiple photodiodes；The photoelectricity twoPole pipe output end is connect with spectrum stabilization circuit, pre-amplification circuit respectively, photodiode bias voltage input end and bias supplyCircuit output end connection.
The gamma ray detected and natural ray are converted to photoelectron by the scintillation crystal 10.The main detector1 scintillation crystal 10 uses LaBr3 ︰ Ce crystal or CsI:Tl crystal, and main detector 1 is using LaBr3 ︰ Ce in the present embodimentCrystal can make survey meter energy resolution less than 4% (1760KeV of uranium).The scintillation crystal 10 of the anticoincidence detector 2 is adoptedWith the CsI:Tl crystal with a thickness of 4cm.The optocoupler zoarium 11 couples photoelectron on photodiode, and optocoupler zoarium 11 makesIt is up to 94% acrylic material with high transparency material, such as light transmittance, improves photoelectronic collection efficiency.
After the photodiode receives incident photoelectron, generation " electron-hole " is right, and then output current signal,The current signal of output is directly proportional to incident photon.The main detector 1 uses multiple photodiodes, effective in order to improvePhotoelectron receiving area is to improve energy resolution, and the present embodiment main detector 1 uses 9 photodiodes, surveysIt is 3.76% (1460keV of K-40) to energy resolution, the resolution ratio to Cs-137 is 5.5%.It is connect with photodiodeThe number of pre-amplification circuit and the number of photodiode are identical.The photodiode that the anticoincidence detector 2 usesNumber is at least one, and the photodiode number that the present embodiment anticoincidence detector 2 uses is 1, therefore corresponding preceding storingThe number of big circuit is also 1.
In conjunction with shown in Fig. 6-7, the spectrum stabilization circuit is made of current monitoring part and temperature sensing part, the electric currentMonitoring part input terminal is connect with photodiode, the multiple tracks point of current monitoring part output end and electronics element cell 3Circuit connection is analysed, the temperature sensing part monitors 10 temperature of scintillation crystal, temperature sensing part output end and electronics unitThe multi-channel analysis circuit connection of room 3, the multi-channel analysis circuit and bias power supply circuit pressure feedback port of electronics element cell 3 connectIt connects.
The method of the spectrum stabilization circuit are as follows: current monitoring part and temperature detection part complement each other and work at the same time, withHave the function that spectrum stabilization.Wherein, the reverse leakage current of each photodiode of current monitoring part monitors, the current monitoring portionDivide and be mainly made of current-voltage amplifier, the INA260 amplifier of TI can be used.Current monitoring part monitors the t1 momentReverse leakage current be output to multi-channel analysis circuit, the reverse leakage current of t1 reception is passed through AD conversion by multi-channel analysis circuitIt for digital signal and is saved in memory, when multi-channel analysis circuit receives next t2 moment current monitoring part transmissionWhen reverse leakage current, multi-channel analysis circuit can compare the reverse leakage current of t2 reception and the reverse leakage current at t1 momentCompared with, can be by each bias power supply circuit when the reverse leakage current of the reverse leakage current of t2 reception ratio t1 reception is bigOutput voltage turn down；It, can will be each when the reverse leakage current of the reverse leakage current of t2 reception ratio t1 reception is smallThe output voltage of bias power supply circuit tunes up.Photodiode input offset voltage is finely tuned by Real-time Feedback reverse leakage current,Make each photodiode under the conditions of different temperatures, different counting rates, average drain currents are consistent.Guarantee each photoelectricity twoPole pipe is not influenced by temperature, so that the present invention composes drift very little.
Temperature detection part is mainly made of temperature sensor, detects 10 temperature of scintillation crystal, institute by temperature sensorIt states the temperature transition that temperature sensor will test and is sent to multi-channel analysis circuit at voltage value, multi-channel analysis circuit is according to temperatureDegree, voltage response finely tune the voltage value of each photodiode voltage, make photodiode under different temperatures environment,The pressurization being consistent, the temperature of photodiode, voltage response are in linear relation, by formula y=0.0567x-1.394It indicates, y represents the trim voltage value of voltage in formula, and unit V, x are temperature, unit DEG C.Table 1 is temperature detection part to notSynthermal actual characteristic test value and design characteristics calculated value.
Table 1
| T(℃) | Δ HV measured value (V) | Δ HV design value (V) |
| 3.8 | -1.176 | -1.179 |
| 4.5 | -1.130 | -1.139 |
| 5.0 | -1.104 | -1.111 |
| 6.0 | -1.048 | -1.054 |
| 9.9 | -0.832 | -0.833 |
| 15.0 | -0.570 | -0.544 |
| 24.8 | 0.022 | 0.011 |
| 26.5 | 0.128 | 0.108 |
| 28.0 | 0.200 | 0.193 |
| 32.0 | 0.425 | 0.419 |
By data in table as it can be seen that the output of circuit meets desired design value, linear fit, fitting side are carried out according to measured valueJourney are as follows: y1=0.0569x1-1.3928.Measured value fit equation slope and design value equation slope difference are 0.35%, and are cutAway from difference only influence the absolute value of spectral line peak position, spectrum drift is had no effect on, so can effectively solve temperature to photodiode bandThe influence come, to solve the problems, such as that spectrum drift is larger.Using spectrum stabilization method of the invention make the spectrum stabilization performance of photodiode withThe same magnitude is in using the conventional energy disperse spectroscopy of photomultiplier tube, about ± 0.5/DEG C.
The bias power supply circuit provides required bias voltage for photodiode, and photodiode needs independent supplyElectricity, therefore the quantity of photodiode is as the quantity of bias power supply circuit.Bias power supply circuit of the present invention uses integrated boostThe mode of type Switching Power Supply combination charge pump, the present embodiment power supply chip use LT3482 scheme, and Linear public affairs can also be used certainlyOther IC products of department, such as LT3571.By power supply chip described in actual test may be implemented output area covering 60~80V, Ripple Noise is less than 5mV, if Ripple Noise is unsatisfactory for requirement and can be further decreased by adding what RC filter circuitNoise, so that bias power supply circuit output voltage stability is high, Ripple Noise is low, high conversion efficiency.The bias power supply circuitThe area of pcb board is suitable with a mao coin area, and the bias power supply circuit is succinctly small and exquisite, is greatly reduced this hairBright volume and weight.
The pre-amplification circuit is the fast current amplification circuit of an encapsulation on the photodiode, by photodiodeThe current signal of output amplifies processing.As shown in figure 8, the summing circuit of the electronics element cell 3 will be by before multiplePut big circuit output pulse signal carry out summation process, the output end of multiple pre-amplification circuits respectively with summing circuitMultiple input channels connect, and summing circuit only draws tetra- input channels of I1-I4 in the present embodiment, and four pre-amplification circuits are defeatedFour pulse signals out pass through tetra- input channels of I1-I4 respectively and enter in operational amplifier U1A, pass through operational amplifierU1A is exported after carrying out summation process by channel O1, and the input channel of summing circuit is determined according to actual photodiode numberNumber, as the main detector 1 of the present embodiment uses 9 photodiodes, the then input for the summing circuit connecting with main detector 1Number of active lanes is 9, and the anticoincidence detector 2 of the present embodiment uses 1 photodiode, therefore does not need to sumProcessing.
The anticoincidence circuit and multi-channel analysis circuit production of the electronics element cell 3 not only subtract on one piece of circuit boardCircuitry plate quantity is lacked and has reduced line between plate, while having avoided between plate that the mutual of device does on line and circuit boardIt disturbs, improves circuit level and circuit reliability.The anticoincidence circuit with CPLD (Complex programmable logical device) be core, it is additionalAdjustable delay unit and signal width adjustment unit.The Complex programmable logical device is logic circuit, for realizing anti-ComptonMeasurement, as shown in figure 9, i.e. only main detector 1 detects signal, and any one of multiple anticoincidence detectors 2 do not detectTo signal, it is to exclude Compton effect that just output one, which receives signal in signal notice multi-channel analysis circuit moment main detector 1,It should be with the signal of photon escape.The effect of the adjustable delay unit is to eliminate each detector time difference problem, and the signal is wideAdjustment unit effect is spent to adjust each detector output signal pulsewidth, to meet the requirement of anti-health measurement.The multi-channel analysis electricityRoad uses arm processor, while also including quasi- Gauss integration circuit, and the quasi- Gauss integration circuit uses 3 grades of Second Order Integral electricityWhat road was realized, anticoincidence circuit output signal is formed using quasi- Gauss integration shaping circuit after satisfaction meets the requirements, withSolve the high-frequency noise being superimposed in the asymmetrical characteristic and signal of the signal.The quasi- Gauss integration circuit output of arm processorDigital signal is handled, and measurement spectral line is accumulated as, and the spectral line of acquisition is divided into the spectral line after original spectral line and anticoincidence by ARM,The information that record is met to event simultaneously, in time of measuring, ARM is periodically to palm display unit transmission measurement spectral line.Anti- symbolIt closes circuit and multi-channel analysis circuit can effective suppression circuit noise, cosmic-ray background, effectively inhibition atmosphere and ambient enviroment gammaBackground, effectively inhibition Compton scattering ray, 20 to 60 times lower than the background of conventional spectrometer.
Preferably, a kind of basic structure of the device of spectral measurement is that main detector 1 is nested anti-into " well " typeMeet detector 2, a kind of shape of the device and method of spectral measurement of the present embodiment is cuboid, and main detector 1 is cubeBody or cuboid, 4 shapes are that the anticoincidence detector 2 of cuboid is mutually spliced into intersecting parallels structure.
Preferably, a kind of shape of the device of spectral measurement can also be that cylindrical body, main detector 1 can be cylinderShape, multiple anticoincidence detectors 2 are spliced into the annular structure matched with main detector 1, and so-called match refers to main detectionDevice 1 can just be put into the annular structure that multiple anticoincidence detectors 2 form.
In conjunction with shown in Fig. 1-10, using spectral measurement of the present invention device detection method for example: the present invention was usingCheng Zhong, incident photon first passes around window 6 and receives and generate photon by the scintillation crystal in main detector 1, while passing through main spyThe optocoupler zoarium surveyed in device 1 is coupled in 9 photodiodes and passes through 9 channel pre-amplification circuit output pulse signals, asksSummation process is carried out to output pulse signal with circuit.The higher photon of energy will also enter multiple anticoincidence and visit in incident photonIt surveys and is coupled in photodiode in device 2 by optocoupler zoarium and passes through pre-amplification circuit output pulse signal；Then, anti-symbolThe pulse for the pulse signal and the output of multiple anticoincidence detectors 2 that the summing circuit of main detector 1 exports will be believed by closing circuitNumber coincidence measurement is carried out, because of the higher incident photon of the energy output pulse letter in main detector 1 and anticoincidence detector 2 simultaneouslyNumber, therefore be unsatisfactory for meeting the requirements, it will the higher incident photon of energy is masked, because the lower incident photon of energy can only lead to1 output pulse signal of main detector is crossed, satisfaction meets the requirements；Subsequently, satisfactory output pulse signal is passed through quasi- highThis integral shaping circuit is formed, and is recently entered multi-channel analysis circuit and is analyzed and processed, in time of measuring, multiple tracks pointCircuit timing is analysed to palm display unit transmission measurement spectral line, meanwhile, the current monitoring part of spectrum stabilization circuit and temperature detectionPart, respectively to the leakage current of multi-channel analysis circuit transmission photodiode and the temperature of scintillation crystal 10.Multi-channel analysis electricityRoad is according to the output voltage of leakage current and temperature real-time control bias power supply circuit.
The present invention is based on more photodiodes, Multi probe meet it is effective with the noise of anticoincidence and background ray suppressing methodInhibit the noise of optical read-out device, effectively inhibits cosmic-ray background, effectively inhibits atmosphere and ambient enviroment gamma background, effectively suppressionCompton scattering ray processed, so that the sensitivity and high resolution of instrument；Along with the higher detection efficient type of selectionLaBr3 ︰ Ce crystal further increases the sensitivity of instrument with resolution ratio；Selection is able to achieve using multi-detector united modeProperty the gamma rays that is projected upwards from underground near normal of detection, can more concentrate effectively reflection sensing point underground diameter about 5cm,Depth up to uranium element in the circular cone column Rocks, Soils of nearly 1m average content, it is sensitiveer to abnormal judgement with it is accurate so thatDirective property of the invention is good；Meet detection using more photodiodes, it will be so that detector has small size, high-resolution excellentPoint；Along with the element circuit of small size makes light-weight equipment of the present invention, have structure simple, at low cost and easy to carryThe advantages of；The spectrum stabilization performance of photodiode is made using spectrum stabilization method of the invention and using the conventional power spectrum of photomultiplier tubeInstrument is in the same magnitude, about ± 0.5/DEG C.
The foregoing is merely illustrative of the preferred embodiments of the present invention, is not intended to limit the invention, all in essence of the inventionWithin mind and principle, any modification, equivalent replacement, improvement and so on be should all be included in the protection scope of the present invention.