CN104730560B - A kind of apparatus and method for reappearing radioactive source radiation field reclaimed water absorbed dose of radiation - Google Patents
A kind of apparatus and method for reappearing radioactive source radiation field reclaimed water absorbed dose of radiation Download PDFInfo
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Abstract
The invention discloses a kind of apparatus and method for reappearing radioactive source radiation field reclaimed water absorbed dose of radiation.Described device includes：Ray radiation unit, for providing radioactive source ray radiation field；Running environment constant temperature unit, for providing stable temperature environment to be placed on its internal detector cells；Detector cells, the change in resistance for emittance to be converted into thermistor；Signal monitoring unit, the temperature rise numerical value for obtaining the detector cells that emittance is caused.The present invention can realize the measurement of the ionising radiation temperature rise of high-purity water environment and 0.1mK/min of the constant temperature (4 ± 0.0001) DEG C of certain volume, and can be in high-energy photon and water interaction process, the heat waste that the influence of convection current, heat transfer and the participation of chemical energy to water are brought carries out quantitative assessment.
Description
Technical field
It is more particularly to a kind of for reappearing radioactive source spoke the present invention relates to the basic measurement technology that field is measured in ionising radiation
Penetrate an apparatus and method for reclaimed water absorbed dose of radiation.
Background technology
Water absorbent amount is one of most basic, most important physical quantity during ionising radiation metering is learned, and is international metering benchmark
The crucial comparison project of Agreement on mutual recognition.The physical quantity give the energy of illuminated material using radiation represent biological effect or its
Its effect, is defined as the emittance that unit mass in material is absorbed, and the energy ionizing radiation that unit material water is absorbed is determined
Justice is water absorbent amount, and unit is gray(Gy) (Gy), 1Gy=1J/kg.
Water calorimeter is absorbed dose of radiation realization most straightforward approach, is turned by measuring energy caused by high energy photon irradiation
Change, the temperature rise of the water absorbent that interaction of photon with materials is caused calculates absorbed dose of radiation using specific heat.
The reproduction difficulty of high-energy photon water absorbent amount is embodied in following aspects, is first how to realize certain volume
Constant temperature (4 ± 0.0001) DEG C high-purity water environment and 0.1mK/min ionising radiation temperature rise measurement, next to that high energy light
In son and water interaction process, how the convection current of water, the influence of heat transfer and the participation of chemical energy, the heat waste brought will determine
Amount is evaluated.
The content of the invention
One object of the present invention, is to propose a kind of device for reappearing radioactive source radiation field reclaimed water absorbed dose of radiation,
The device can realize high-purity water environment of the constant temperature (4 ± 0.0001) DEG C of certain volume.
A further object of the present invention, is to propose a kind of dress for reappearing radioactive source radiation field reclaimed water absorbed dose of radiation
Put, the device can realize the measurement of the ionising radiation temperature rise of 0.1mK/min.
Another object of the present invention, is to propose a kind of side for reappearing radioactive source radiation field reclaimed water absorbed dose of radiation
Method, in can realizing high-energy photon and water interaction process, quantitative assessment of each factor for heat waste.
It is that, up to this purpose, the present invention uses following technical scheme：
A kind of device for reappearing radioactive source radiation field reclaimed water absorbed dose of radiation, including：
Ray radiation unit, for providing radioactive source ray radiation field；
Running environment constant temperature unit, for providing stable temperature environment to be placed on its internal detector cells；
Detector cells, the change in resistance for emittance to be converted into thermistor；
Signal monitoring unit, the temperature rise numerical value for obtaining the detector cells that emittance is caused.
Further, the running environment constant temperature unit includes shell, die body, heat exchanger and thermometer, wherein,
The enclosure is provided with first thermal insulation layer；
The die body is set in the housing, and second thermal insulation layer is provided with outside the die body；
The heat exchanger is arranged between the die body and the shell, the medium between the shell and the die body
It is air；
Water is full of in the die body；
The thermometer is used to detect the temperature of air between water and the shell and the die body in die body.
Further, the detector cells are placed in the die body；What is be full of in the die body is deionized water.
Further, also including fan and magnetic stirrer, the fan is arranged between the shell and the die body,
The magnetic stirrer is arranged on the bottom of the die body.
Further, adjustment platform is provided with the die body, for being adjusted for the detector cells being placed on it do position
It is whole.
Further, the detector cells include calorimetric core and temperature sensitive probes, and the calorimetric core inner is provided with high-purity
Water, the temperature sensitive probes are placed on the calorimetric core inner.
Further, the calorimetric core includes center section, the two end portions of the second precision of the first precision, the first precision
Higher than the second precision.
Further, the center section of the first precision is cylinder, and the two end portions of the second precision are cone, further
, the center section of first precision is processed using the technology that grinds of optical lens.
Further, also including the glass tube for accommodating thermistor in the temperature sensitive probes, the glass tube is two
Root, is each passed through the two end portions of the calorimetric core and is placed in the calorimetric core center.
Further, high purity water is not completely filled with calorimetric core, also maintains a small amount of air.
Further, it is obtained as follows：
Step A, the shaping of calorimetric core non-once, and it is divided into the center section of cylinder and the two ends and centre of cone
Two parts of the glass tube of temperature sensitive probes three, first, using inscribing technique cylinder center section circumference on every 90 °
Make marks line, using ceramic texturing technology and by 560 DEG C of annealing, line width 0.4mm, for temperature sensitive probes, calorimetric core and mould
Positioning between body；Then, the Dimensions metrology of calorimetric core is completed, critical size is wall thickness and diameter；Next, three parts are filled
With combination；
After step B, calorimetric core water-filling, before sealing, fill high-purity H2 and maintain more than 1.5 hours, to ensure saturation；Finally
Using sleeve pipe airing form, sealing station is being needed, filling a small amount of N2 gas, to ensure that flame sealed glass tube is safe；Finally,
Calorimetric core will not be completely filled with water, can keep a certain amount of air, unlikely to ensure when water temperature changes between (4-22) DEG C
In the structure of destruction glass container；
In water temperature, calorimetric core in step C, die body between water temperature and die body and shell air temperature, 3 temperature
Drift be stable in 0.1mK/min, then meet the temperature conditionss of radiation test.
Further, the shell is wooden case.
Further, a part for the heat exchanger is arranged in the die body.
Further, the die body and the shell offer hole in the horizontal level of the detector cells,
Injected for beam.
Further, the signal measurement and control unit include signal excitation module, signal monitoring module, signal-balanced module,
Signal measurement module and magnitude tracing module, wherein,
The signal excitation module is used to export the exchange frequency stabilization voltage signal excitation detector and water body form unit is defeated
The voltage signal for going out, and improve its signal to noise ratio；
The signal monitoring module is used to monitor the change of fixed point current potential；
The signal-balanced module carries out output compensation, keeps the fixed point current potential of monitoring to return just after measurement starts
Initial value；
The signal measurement module according to the instruction of the signal monitoring module, to the output quantity of the signal compensation module
Measure；
The magnitude tracing module is used to trace to the source the physical quantity being related in whole measurement process to the corresponding International System of Units
National standard.
The present invention also provides a kind of method for reappearing radioactive source radiation field reclaimed water absorbed dose of radiation, and it uses foregoing any
Reproducing apparatus are planted, wherein,
In the method for the reproduction, influence water absorbent amount realization correction term be set to heat transfer correction term,
Thermal convection current correction term, Disturbance of radiation field correction term, section dose gradient correction term, water density change correction term and heat waste amendment
.
Further, the ray radiation unit is used60Co gamma emitters, the reproduction formula of the water absorbent amount is：
In formula,
ΔTwAt reference depth, at 4 DEG C, the temperature of the calorimetric core that ionising radiation is caused is raised；
cwIt is the specific heat capacity of pure water, at 4 DEG C, value is 4.205 × 103J/(kgK)；
kcIt is heat transfer correction term；
kvIt is thermal convection current correction term；
kpIt is Disturbance of radiation field correction term, i.e. temperature sensitive probes and the next Disturbance of radiation field of calorimetric core ribbon；
kddIt is section dose gradient correction term；
kρWater density change correction term during for realization and calibration；
kHDIt is heat waste correction term.
The present invention can realize high-purity water environment and 0.1mK/min of the constant temperature (4 ± 0.0001) DEG C of certain volume
The measurement of ionising radiation temperature rise, and can be in high-energy photon and water interaction process, the shadow of convection current, heat transfer to water
Ringing the heat waste brought with the participation of chemical energy carries out quantitative assessment.
Brief description of the drawings
A kind of dress for reappearing radioactive source radiation field reclaimed water absorbed dose of radiation that Fig. 1 is provided by first embodiment of the invention
The block diagram put；
Fig. 2 is the structural representation of the running environment constant temperature unit of offer in third embodiment of the invention；
Fig. 3 be sixth embodiment of the invention in, provide60In Co field of radiation, different exposure times, what heat transfer was caused
Calorimetric core temperature variation curve；
Fig. 4 be sixth embodiment of the invention in, provide60In Co field of radiation, the specific amendment knot of different exposure times
Really.
Specific embodiment
Further illustrate technical scheme below in conjunction with the accompanying drawings and by specific embodiment.
First embodiment
A kind of dress for reappearing radioactive source radiation field reclaimed water absorbed dose of radiation that Fig. 1 is provided by first embodiment of the invention
The block diagram put；Referring to Fig. 1, the device includes：
Ray radiation unit 100, for providing radioactive source ray radiation field；
Running environment constant temperature unit 200, for providing stable temperature environment to be placed on its internal detector cells；
Detector cells 300, the change in resistance for emittance to be converted into thermistor；
Signal monitoring unit 400, the temperature rise numerical value for obtaining the detector cells that emittance is caused.
Second embodiment
In the second embodiment of the present invention, described in the device for reappearing radioactive source radiation field reclaimed water absorbed dose of radiation
Ray radiation unit 100, it is exemplary, use60Co gamma emitters, but it should be understood by those skilled in the art that using other
Appropriate radiation source is equally feasible.
Specifically,60Co gamma ray radiators activity is 300TBq (on January 1st, 2009), is Russian import high specific activity60Co
Radiation source, volume is φ 23.8mm × 34.8mm.Radiation source is fixed in the source chamber of Safety Irradiation device, and source chamber is by tungsten alloy structure
Into density is slightly below 18.95g/cm3.Source chamber is a diameter of 100mm, the cylinder of a length of 100mm, coaxial with radioactive source.Go out beam hole
It is also co-axial just to radioactive source.Go out a diameter of 45mm of beam hole, effect of the diaphragm system to source is not influenceed.Irradiation devices are used
Electronic rotation shutter control radiation source beam, shutter is between source chamber and collimater, when rotating shutter and radiation source and collimation
When device exit portal overlaps, beam is opened, when on rotating shutter the axis in duct and beam axis at an angle of 90 when beam close.
Collimater is made up of tungsten alloy, is designed according to ISO4037 standards.The shell of irradiator is made of stainless steel material, internal profit
With lead as shielding material, using single placingJi Shu, it is ensured that seamless.
3rd embodiment
In third embodiment of the invention, for the operation in the device for reappearing radioactive source radiation field reclaimed water absorbed dose of radiation
Environmental Incubator unit 200, for providing stable temperature environment to be placed on its internal detector cells.
The structural representation of the running environment constant temperature unit that Fig. 2 is provided for the embodiment.It is exemplary referring to Fig. 2, it is described
Running environment constant temperature unit includes shell 1, die body 2, heat exchanger 3 and thermometer 4,
The die body 2 is arranged in the shell 1, the heat exchanger 3 be arranged on the die body 2 and the shell 1 it
Between, thermal insulation layer 5 is externally provided with the die body in the shell, more specifically, the enclosure is provided with first thermal insulation layer, institute
State and second thermal insulation layer is provided with outside die body.
The shell uses wooden case.
The detector cells 300 are placed in the die body 2, in the die body 2 be full of water, the wooden case 1 with it is described
Medium between die body 2 is air,
The thermometer 4 is used to detect the temperature of air between water and the wooden case 1 and the die body 2 in die body 2,
The die body 2 and the wooden case 1 offer hole in the horizontal level of the detector cells 300, are used for
Beam is injected.
Exemplary, a part for the heat exchanger 5 is arranged in the die body 2.
Exemplary, also including fan (depending on not going out in figure) and magnetic stirrer 6, the fan is arranged on the shell 1
Between the die body 2, the magnetic stirrer 6 is arranged on the bottom of the die body 2.
Exemplary, adjustment platform (depending on not going out in figure) is provided with the die body 2, for being the detector being placed on it
Unit 300 does position adjustment.
Specifically, the shell in the present embodiment is wooden case of 85cm for the length of side, its inwall be provided with 5cm it is thick every
Hot polymerization styrenic foams；
The die body is that the length of side is the lucite chest of 30CM, deionized water (tertiary effluent) is filled with inside it, outside it
Wall is wrapped up by 5cm thick heat-insulated polystyrene foam, and die body bottom is provided with magnetic stirrer, for balancing water temperature.On die body
Lid sets the reserved wire guide (depending on not going out in figure) of promising platinum resistance thermometer, calorimetric core, at the ray incidence of die body, opens up
The hole for having length and width to be 12cm, 3cm, is placed with the polyphenyl for dismountable 5cm thickness that a size matches with hole in the hole
Vinyl foam；
The die body is placed in the middle of the shell, and fan and heat exchange are provided between the shell and the die body
Device, in order to the part for accelerating the control of temperature, the heat exchanger is arranged in the die body, flows by heat exchanger
Refrigerant control die body in water temperature, realize the control of arbitrary temp between 0 DEG C to 25 DEG C in die body, the running environment constant temperature
Deionized water in unit internal model body is down to 4 DEG C of times for generally needing or so 4 hours from 20 DEG C of room temperature.Water-bath system is controlled
The temperature of liquid can be stablized at ± 0.1 DEG C in heat exchanger.The temperature of air was calibrated by one between die body and wooden case
RTD is monitored, it is ensured that the control of air circulation and temperature.The thermometer is used to detect water and the wooden case and institute in die body
State the temperature of air between die body.
Fourth embodiment
For the detector cells 300 in the device for reappearing radioactive source radiation field reclaimed water absorbed dose of radiation, for by spoke
Penetrate the change in resistance that energy is converted into thermistor.
Exemplary, the detector cells 300 include calorimetric core and temperature sensitive probes, and the calorimetric core inner is provided with height
(high purity water is the high water of chemical purity to pure water, by the conducting medium almost all removal in water, and the glue that will do not dissociated in water
Body material, gas and organic matter are removed to very low degree, and the content of impurity therein is less than 0.1mg/L.Current people are made
The purity of high purity water reached 99.999999%, wherein impurity content is less than 0.01mg/L.High purity water refers mainly to the temperature of water
Spend for 25 DEG C when, electrical conductivity be less than 0.1us/cm, pH value be 6.8-7.0 and removal other impurities and bacterium water), the temperature-sensitive
The thermistor of probe is placed on the calorimetric core inner.
Exemplary, the calorimetric core includes center section, the conical two ends of low precision of high-precision cylinder
Part.Exemplary, the cylindrical center section of the calorimetric core is processed using the technology that grinds of optical lens.
Exemplary, the temperature sensitive probes include glass tube, wire and thermistor, and the glass tube is two, respectively
It is placed in the calorimetric core center through the two ends of the calorimetric core.
Specifically, the glass tube of the temperature sensitive probes in the present embodiment, its material is Pyrex glass, and its original dimension is
Diameter 8mm, wall thickness 1mm, are heated drawing, and the size after drawing is external diameter 0.5-0.6mm, wall thickness 0.06-0.11mm, length
The pipe of 4cm, internal diameter is maintained at 0.3mm, and by metal line justification.Its end points is sealed by flame, and is tested with He leak detectors；
The thermistor is bead thermistor, its a diameter of 0.25mm, and the diameter wire of the thermistor is
0.03mm；
The wire 160cm long, since end, (shielding line is also herein to divest the external insulation layer 11cm of wire for wire
Block), the inner insulating layer 5cm of wire is divested, per share many copper cash initially stay three, and welding is completed and removes remaining two after testing
Root, the line footpath of the copper cash is 0.1mm；
The lead of thermistor is welded with wire, wherein lead puts the tubule of 0.2mm diameters, for preventing two
Wire contacts short circuit, the 8cm long of the tubule constitutes by three sections linked into an integrated entity, and a length is 1cm, 4cm and 3cm, its
One section of 1cm is most thick, and a section of 4cm is most thin, and the end points that wire is peeled off applies epoxy resin and fixed with by two wires.Then by heat
Quick resistance and its wire are fixed on (60 DEG C of operating temperature) in glass tube using NSC 77136, and thermistor is placed on the glass
Be fixed on shielding line in glass tube using polytetrafluoroethylene (PTFE) by the termination of pipe, the other end, after outer wall applies silica gel, set emulsion tube (5 years
Change), length 100cm, it is ensured that the waterproof of temperature sensitive probes, the other end of emulsion tube until outside Water ball, two temperature sensitive probes with
Measuring system is connected.
The glass tube is fixed in polytetrafluoroethylene (PTFE) three-jaw, and by polytetrafluoroethylene (PTFE) three-jaw by the temperature sensitive probes amount of being fixed on
In hot core, the temperature sensitive probes are located at the axle center of the calorimetric core, and its positional precision is 0.5mm.
Thermistor and the welding of wire, using common scolding tin, apply a small amount of welding compound at contact before welding, certain to note
Scolding tin consumption will lack, and it is 700 °F that common cusp electric iron sets temperature, be that miniature sleeve pipe is being moved back to bead thermistor glass
During pearl end points, certain space is stayed, otherwise solder joint easily comes off, aforesaid operations are carried out under the microscope, and coordinate various solid
Clamp has.
Specifically, the calorimetric core in the present embodiment is glass container, 75mm, 68 ± 0.2mm of diameter are about, center section is
Cylinder, two ends are cone.A pair of temperature sensitive probes are placed in calorimetric core center by glass tube from two ends.
The cylindrical center section of calorimetric core is processed using the technology that grinds of optical lens, improves wall thickness control
Precision and the uniformity.Calorimetric core non-once shapes, and is divided into the center section of cylinder and the two ends and centre of cone
Two glass tubes of temperature sensitive probes, before the combination of three parts, are marked on the circumference of center section using inscribing technique every 90 °
Note line, using ceramic texturing technology and by 560 DEG C annealing, line width 0.4mm, for temperature sensitive probes, calorimetric core and die body it
Between positioning.The Dimensions metrology of calorimetric core is also to be completed before three parts are assembled, and critical size is wall thickness and diameter.
After calorimetric core water-filling, before sealing, high-purity H is filled2And maintain more than 1.5 hours, to ensure saturation.It is final to use set
Pipe airing form, is needing sealing station, fills a small amount of N2Gas, to ensure that flame sealed glass tube is safety.Calorimetric core will not be complete
Portion is full of water, can keep a certain amount of air, to ensure, when water temperature changes between (4-22) DEG C, to be unlikely to destruction glass appearance
The structure of device.
In water temperature, calorimetric core in die body between water temperature and die body and shell air temperature, 3 drifts of temperature
0.1mK/min is stable in, then meets the temperature conditionss of radiation test.
5th embodiment
The signal monitoring unit 400, the temperature rise numerical value for obtaining the detector cells that emittance is caused.
The signal measurement and control unit includes signal excitation module, signal monitoring module, signal-balanced module, signal measurement mould
Block and magnitude tracing module, wherein,
The signal excitation module is used to export the exchange frequency stabilization voltage signal excitation detector and water body form unit is defeated
The voltage signal for going out, and improve its signal to noise ratio；
The signal monitoring module is used to monitor the change of fixed point current potential；
The signal-balanced module carries out output compensation, keeps the fixed point current potential of monitoring to return just after measurement starts
Initial value；
The signal measurement module according to the instruction of the signal monitoring module, to the output quantity of the signal compensation module
Measure；
The magnitude tracing module is used to trace to the source the physical quantity being related in whole measurement process to the corresponding International System of Units
National standard.
Sixth embodiment
The present embodiment provides a kind of method for reappearing radioactive source radiation field reclaimed water absorbed dose of radiation, and it uses foregoing any
Reproducing apparatus described in claim, in the method for the reproduction, influence the correction term of the realization of water absorbent amount to set
For heat transfer correction term, thermal convection current correction term, Disturbance of radiation field correction term, section dose gradient correction term, water density change are repaiied
Positve term and heat waste correction term.
Exemplary, the ray radiation unit is used60Co gamma emitters.
Exemplary, the reproduction formula of the water absorbent amount is：
In formula,
ΔTwAt reference depth, at 4 DEG C, the temperature of the calorimetric core that ionising radiation is caused is raised；
cwIt is the specific heat capacity of pure water, at 4 DEG C, value is 4.205 × 103J/(kgK)；
kcIt is heat transfer correction term；
kvIt is thermal convection current correction term；
kpIt is Disturbance of radiation field correction term, i.e. temperature sensitive probes and the next Disturbance of radiation field of calorimetric core ribbon；
kddIt is section dose gradient correction term；
kρWater density change correction term during for realization and calibration；
kHDIt is heat waste correction term.
Specifically, determining heat transfer correction term：
For calorimetric core, the temperature change that heat transfer brings, essentially from two aspects.First, due to glass
Specific heat capacity is the 1/6 of water, so, same radiation condition and under the time, if do not considered glass is passed in water in irradiation process heat
Amount, the temperature rise of glass also will be 6 times of water.Second, the dose gradient distribution in water can bring temperature gradient distribution, this also will
Transition temperature change can be carried out to calorimetric core ribbon.
Water calorimeter model is done into following simplification to calculate the heat-conduction effect from glass：It is uniformly to penetrate that calorimeter is suffered
Beta radiation；Calorimetric core is infinitely long cylinder；Temperature sensitive probes are symmetrical in glass tube end；Two glass tubes are semi-infinite long
Cylinder.Under these conditions, foundation is axisymmetric model, actually by problem reduction for bidimensional problem, can use warp
Allusion quotation heat transfer formula describes above mentioned problem, so as to carry out mathematical computations.It is zero point to radiate the time for starting, with the discrete time
Step, calculates the heat conductive process of each rectangular mesh.Temperature effect first at computation and measurement point, as radiated time becomes
Change, the change of temperature after calculating, you can obtain the amendment of conduction effect.
Fig. 3 is provided for the present embodiment60In Co field of radiation, different exposure times, the calorimetric core temperature that heat transfer is caused becomes
Change curve；Referring to Fig. 3, it can be seen that the rapid reduction of temperature is due to the additional heat from glass tube heat transfer after radiation
In having conducted water by central shaft, increasing for ensuing temperature is because the heat of calorimetric core glass reaches temperature sensitive probes.
Fig. 4 is provided for the present embodiment60In Co field of radiation, the specific correction result of different exposure times.According to experiment condition,
Drift time is 120s after exposure time and irradiation, so this is modified to 0.9986.
For60The X-ray of Co gamma rays or higher energy, larger dosage distributed areas are built-up areas in irradiation water
Or radiation field edge.If calorimeter is operated in outside maximum dose point, and radiation field size size is sufficiently large (10cm*10cm), that
The heat-conduction effect that dose gradient brings can be ignored.When carrying out electron beam absorbed measurement, this just needs carefully meter
Calculate, 15MeV electron beam irradiation 120s, at depth of water 5cm, up to 0.5%.
Specifically, determining thermal convection current correction term：
Thermal convection current is that liquid calorimeter will be in face of a peculiar problem, if the water in calorimeter has dose gradient caused
Thermograde, due in gravitational field local density change can buoyancy can produce change, this can cause the stream of liquid internal
Dynamic, the liquid of flowing can transmit heat.Flow rate is relevant with absorbed dose of radiation and time, so effective Heat transmission of measurement point
Coefficient is change.Under the conditions of this kind of, according to before and after radiation drift extrapolation midpoint method come obtain thermal convection current transmission will not
It is again accurate method.
Much may can all cause the thermal convection current in water calorimeter.As ambient temperature changes, or x ray irradiation x
Period, if temperature controlled undesirable in die body, thermal convection current can be produced in the big local location of any thermograde；Heat
Quick probe due to self-heating effect, if there are sharp temperature distribution gradients, its local location is likely to occur thermal convection current；It is non-aqueous
Material is in the position with water directly contact, the thermograde produced during irradiation, also there may be thermal convection current.
Because the coefficient of cubical expansion that 4 DEG C is water is 0, so the operation temperature of water calorimeter is set into 4 DEG C, can reduce
The influence of thermal convection current.The power of temperature sensitive probes can not consider the convection effect that probe brings when being less than 50 μ W, and this calorimeter
Its power is 5 μ W, so ignoring the source impact.
Finally, the operation temperature of calorimeter is being set to 4 DEG C by us, and thermal convection current correction term now is 1, while the present apparatus
(0-30) DEG C can be operated in, when being operated in 22 DEG C, its kv=0.993.
Specifically, determining Disturbance of radiation field correction term：
The presence of calorimetric core and glass probe has disturbed radiation field, and the amendment can be measured by small size ionisation chamber, by having
Ratio without calorimetric core is obtained.
Measurement is obtained60In Co radiation fields, kp=1.0021 ± 0.0005.Calculate and understand, 0.9mm glass will penetrate Co-60
Line attenuation 0.6%, above-mentioned measured value shows that ray weakens partly to be scattered by glass and strengthens caused by calorimetric core.By entering one
The illiteracy snap gauge of step intends may certify that this point that simulation result of calculation is kp=1.0022 ± 0.0008.
Specifically, determining section dose gradient correction term：
The section dose gradient of x-y plane is also to be modified by small size ionisation chamber measurement.A pair of glass temperature sensitive probes
End points spacing 1cm, centered on the calibration point of ionisation chamber, by ionisation chamber measure the entire profile dose value, you can repaiied
Just.Kdd=0.9971. when energy is 10MV
Specifically, determining water density correction：
Ionisation chamber is calibrated in room temperature, and in North America, its standard conditions is 101.325kPa, and 22.00 DEG C, China is
101.325kPa, 20.00 DEG C.This is modified to 1.0005.
Specifically, determining heat waste correction term：
One most basic hypothesis of calorimeter measurement absorbed dose of radiation is exactly that energy ionizing radiation sinks all in the form of heat
Accumulate in calorimetric core, and in fact, to consider the energy of other forms deposition.The energy of all depositions is expressed as Ea, with heat
Form performance is Eh, heat waste can just be expressed as：
It should be noted that heat waste can just can be born, physics and change of the aqueous systems under radiation-induced are specifically dependent upon
Learn change.By Ar, N2、H2、H2/O2Etc. the comparing of different system, H2Saturation aqueous systems, after being irradiated by more than 100Gy, can
To think that its heat waste is zero.
The sealing calorimetric core of the present apparatus uses H2Saturation aqueous systems, khd=1.
To sum up, after all physical parameters and correction term has been obtained, photon energy 10MV, SSD=100cm, depth of water 10cm,
Each parameter and its uncertainty of water absorbent measurement as shown in figure 4,10MV photon survey water absorbent amounts synthetic standards not
Degree of certainty is 0.35%.
Claims (9)
1. a kind of device for reappearing radioactive source radiation field reclaimed water absorbed dose of radiation, it is characterised in that：Including：
Ray radiation unit, for providing radioactive source ray radiation field；
Running environment constant temperature unit, for providing stable temperature environment to be placed on its internal detector cells；
Detector cells, the change in resistance for emittance to be converted into thermistor；
Signal monitoring unit, the temperature rise numerical value for obtaining the detector cells that emittance is caused；
Also, the running environment constant temperature unit includes shell, die body, heat exchanger, wherein,
The enclosure is provided with first thermal insulation layer；
The die body is set in the housing, and second thermal insulation layer is provided with outside the die body；
The heat exchanger is arranged between the die body and the shell, and the medium between the shell and the die body is sky
Gas；
Water is full of in the die body；
Also, the detector cells include calorimetric core and temperature sensitive probes, the temperature sensitive probes are placed on the calorimetric core inner.
2. device according to claim 1, it is characterised in that：The running environment constant temperature unit also includes thermometer, institute
Thermometer is stated for detecting the temperature of air between water and the shell and the die body in die body.
3. device according to claim 2, it is characterised in that：The detector cells are placed in the die body；It is described
What is be full of in die body is deionized water；
Preferably, also including fan and magnetic stirrer, the fan is arranged between the shell and the die body, the magnetic
Property agitator is arranged on the bottom of the die body.
4. the device according to Claims 2 or 3, it is characterised in that：Adjustment platform is provided with the die body, for being placement
Detector cells thereon do position adjustment.
5. device according to claim 1, it is characterised in that：The calorimetric core inner is provided with high purity water.
6. device according to claim 5, it is characterised in that：The center section of the calorimetric core including the first precision, the
The two end portions of two precision, the first precision is higher than the second precision；
Preferably, the center section of the first precision is cylinder, and the two end portions of the second precision are cone, further, institute
The center section for stating the first precision is processed using the technology that grinds of optical lens；
Preferably, also including the glass tube for accommodating thermistor in the temperature sensitive probes, the glass tube is two, respectively
Two end portions through the calorimetric core are placed in the calorimetric core center；
Preferably, high purity water is not completely filled with calorimetric core, also maintains a small amount of air.
7. device according to claim 6, it is characterised in that：It is obtained as follows：
Step A, the shaping of calorimetric core non-once, and it is divided into the center section of cylinder and the two ends of cone and centre two
The part of glass tube three of temperature sensitive probes, first, is marked on the circumference of the center section of cylinder using inscribing technique every 90 °
Note line, using ceramic texturing technology and by 560 DEG C annealing, line width 0.4mm, for temperature sensitive probes, calorimetric core and die body it
Between positioning；Then, the Dimensions metrology of calorimetric core is completed, critical size is wall thickness and diameter；Next, by three part assembling groups
Close；
After step B, calorimetric core water-filling, before sealing, fill high-purity H2 and maintain more than 1.5 hours, to ensure saturation；It is final to use
Sleeve pipe airing form, is needing sealing station, fills a small amount of N2 gas, to ensure that flame sealed glass tube is safe；Finally, calorimetric
Core will not be completely filled with water, can keep a certain amount of air, to ensure, when water temperature changes between 4 DEG C -22 DEG C, to be unlikely to brokenly
The structure of bad glass container；
In water temperature, calorimetric core in step C, die body between water temperature and die body and shell air temperature, 3 drifts of temperature
Shifting is stable in 0.1mK/min, then meet the temperature conditionss of radiation test.
8. device according to claim 2, it is characterised in that the shell is wooden case；
Preferably, a part for the heat exchanger is arranged in the die body；
Preferably, the die body and the shell offer hole in the horizontal level of the detector cells, for penetrating
Wire harness is injected.
9. a kind of method for reappearing radioactive source radiation field reclaimed water absorbed dose of radiation, it is used described in foregoing any claim
Reproducing apparatus, it is characterised in that：
In the method for the reproduction, influence water absorbent amount realization correction term be set to heat transfer correction term, heat it is right
Stream correction term, Disturbance of radiation field correction term, section dose gradient correction term, water density change correction term and heat waste correction term；
Preferably, the reproduction formula of the water absorbent amount is：
In formula,
ΔTwAt reference depth, at 4 DEG C, the temperature of the calorimetric core that ionising radiation is caused is raised；
cwIt is the specific heat capacity of pure water, at 4 DEG C, value is 4.205 × 103J/(kgK)；
kcIt is heat transfer correction term；
kvIt is thermal convection current correction term；
kpIt is Disturbance of radiation field correction term, i.e. temperature sensitive probes and the next Disturbance of radiation field of calorimetric core ribbon；
kddIt is section dose gradient correction term；
kρWater density change correction term during for realization and calibration；
kHDIt is heat waste correction term.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4312224A (en) * | 1980-02-29 | 1982-01-26 | United States Of America | Absorbed dose water calorimeter |
| CN201603305U (en) * | 2010-02-12 | 2010-10-13 | 上海市第一人民医院 | Water tank die body with adjustable thickness |
| WO2013177677A1 (en) * | 2012-05-29 | 2013-12-05 | THE ROYAL INSTITUTION FOR THE ADVANCEMENT OF LEARINING/McGILL UNIVERSITY | Method and system for calorimetry probe |
| CN204496008U (en) * | 2015-03-11 | 2015-07-22 | 中国计量科学研究院 | A kind of device for reappearing water absorbent amount in radioactive source radiation field |
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4312224A (en) * | 1980-02-29 | 1982-01-26 | United States Of America | Absorbed dose water calorimeter |
| CN201603305U (en) * | 2010-02-12 | 2010-10-13 | 上海市第一人民医院 | Water tank die body with adjustable thickness |
| WO2013177677A1 (en) * | 2012-05-29 | 2013-12-05 | THE ROYAL INSTITUTION FOR THE ADVANCEMENT OF LEARINING/McGILL UNIVERSITY | Method and system for calorimetry probe |
| CN204496008U (en) * | 2015-03-11 | 2015-07-22 | 中国计量科学研究院 | A kind of device for reappearing water absorbent amount in radioactive source radiation field |
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