CN103091701A - Multipurpose flight time equipment for measuring quality of cold neutron beam - Google Patents
Multipurpose flight time equipment for measuring quality of cold neutron beam Download PDFInfo
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Abstract
The invention belongs to a two-dimensional measurement technology of cold neutron beam quality, and particularly relates to a multipurpose flight time device for cold neutron beam quality measurement. The structure of the neutron flight tube comprises a first slit device for cold supply neutron beam to pass through, a mechanical chopper is arranged on the rear side of the first slit device and connected with the inlet end of a horizontally arranged neutron flight tube, the outlet end of the neutron flight tube is connected with a second slit device, a detector and a shielding device are arranged on the rear side of the second slit device, and the detector is connected with a computer through a multi-channel time analyzer. The invention has the advantages of exquisite structure, low hardware cost, simpler and more stable whole system, high-precision corner positioning and quick start-up and braking, and can fully meet the requirements of each cold neutron spectrometer on beam energy spectrum and quality parameter measurement by considering the specific design condition of the cold neutron beam transmission system.
Description
Technical field
The invention belongs to cold neutron quality of beam two-dimensional measurement technology, be specifically related to a kind of multi-usage cold neutron quality of beam and measure the flight time equipment of using.
Background technology
The cold neutron energy spectrum is one of basic parameter of neutron scattering experiment and reactor cold neutron source, is also one of important symbol of weighing cold neutron Beam Transport Systems performance and cold neutron scattering experiment level.Abroad generally before and after the cold neutron spectrometer is installed, the cold neutron power spectrum is measured, and the detecting of not timing, result writes in the basic parameter and annual report in research centre.And domesticly at present based on the research work of cold neutron spectral measurement aspect, report being arranged not yet, the surveying work of this aspect still belongs to blank in China.At the beginning of the 9's 0 of last century, China Atomic Energy Science Research Institute carries out the research that HWRR reactor thermal neutron spectrum is measured the earliest, and has developed the easy time of flight arrangement of cover.But the design of this device can not be satisfied cold neutron scattering spectrometer and distribute to comprising beam level, the measurement demand of line angular divergence distribution etc.China is greatly developing at present reactor and spallation neutron source is basic neutron scattering technology, need to build large quantities of high-quality, high-caliber cold neutron scattering spectrometer, and the cold neutron quality of beam is related to the key indexs such as background, efficient and spatial discrimination of cold neutron scattering experiment, external correlation technique details is underground, and independent innovational design is completed technique the development of whole neutron scattering technology is significant.
Summary of the invention
The object of the invention is to from the actual demand of cold neutron scattering spectrometer, provide a kind of light and practical cold neutron quality of beam to measure the flight time equipment of using.
Technical scheme of the present invention is as follows: a kind of multi-usage cold neutron quality of beam is measured the flight time equipment of using, comprise the first slit arrangement that the cooling neutron streaming passes through, the rear side of the first slit arrangement is provided with mechanical chopper, mechanical chopper is connected with the entrance point of horizontally disposed neutron tof tube, the endpiece of neutron tof tube is connected with the second slit arrangement, the rear side of the second slit arrangement is provided with detector and shield assembly, and detector is connected with computing machine by multichannel time analyzer.
Further, multi-usage cold neutron quality of beam as above is measured and is used flight time equipment, wherein, below the first slit arrangement, is provided with monitor over against the neutron streaming direction, and monitor is connected with computing machine by multichannel time analyzer.
Further, multi-usage cold neutron quality of beam as above is measured the flight time equipment of using, wherein, described the first slit arrangement, mechanical chopper, neutron tof tube, the second slit arrangement, detector and shield assembly are installed on same bracing frame, and the bracing frame bottom is connected by rotational drive motor with first substrate.
Further, multi-usage cold neutron quality of beam as above is measured and is used flight time equipment, and wherein, described first substrate is arranged on the horizontal slide rail of second substrate, and is connected with pan drive motor on second substrate.
Further, multi-usage cold neutron quality of beam as above is measured and is used flight time equipment, and wherein, the width adjustable extent of the slit of described the first slit arrangement and the second slit arrangement is 1～20mm, and the height adjustable extent is 2～20mm.
Further, multi-usage cold neutron quality of beam as above is measured and is used flight time equipment, and wherein, the rotor of described mechanical chopper drives at the rotation with in surface perpendicular to the neutron streaming direction by the chopper drive motor.
Further, multi-usage cold neutron quality of beam as above is measured and is used flight time equipment, and wherein, described neutron tof tube is the aluminum pipe that inwall is brushed with the gadolinium oxide material.
Further, multi-usage cold neutron quality of beam as above is measured and is used flight time equipment, and wherein, described detector is
3The He proportional counter tube,
3The He proportional counter tube is arranged in the shield assembly that the Boron-containing-PE material makes, and shield assembly is provided with opening towards the second slit arrangement.
Further, multi-usage cold neutron quality of beam as above is measured and is used flight time equipment, and wherein, described monitor adopts the fission chamber monitor, is connected with multichannel time analyzer through wave-shaping circuit.
Further, multi-usage cold neutron quality of beam as above is measured the flight time equipment of using, wherein, described mechanical chopper is provided with optoelectronic switch, the epitrochanterian perforate of mechanical chopper produces trigger pip measuring period when passing through optoelectronic switch, and optoelectronic switch is connected with multichannel time analyzer.
Beneficial effect of the present invention is as follows: multi-usage cold neutron quality of beam provided by the present invention is measured with flight time equipment and is adopted relatively simple pulsed-beam time-of-flight methods and unique Machine Design, coordinate motor to drive one-piece construction, control translation and the rotation of finishing equipment, realize simultaneously the measurement of cold neutron power spectrum and line parameters.Compare with public technology in the world, advantage of the present invention is delicate structure, give full play to the computer software advantage, the decrease hardware cost, coordinate to complete complicated motion by software and hardware, whole system is simpler and easy stable, has realized the corner location of pinpoint accuracy and has opened fast braking, consider simultaneously cold neutron Beam Transport Systems specific design situation, can fully satisfy each cold neutron spectrometer for the demand of energy spectrum and Q factor measurement.
Description of drawings
Fig. 1 is device structure schematic diagram of the present invention;
Fig. 2 is electronic system block diagram of the present invention;
Fig. 3 is the structural representation of the first and second slit arrangements of the present invention;
Fig. 4-1 is mechanical chopper rotor structure schematic diagram of the present invention;
Fig. 4-2 are the side view of Fig. 4-1.
Embodiment
Below in conjunction with drawings and Examples, the present invention is described in detail.
as shown in Figure 1, multi-usage cold neutron quality of beam provided by the present invention is measured the flight time equipment of using, comprise the first slit arrangement 1 that the cooling neutron streaming passes through, the rear side of the first slit arrangement 1 is provided with mechanical chopper 2, mechanical chopper 2 is connected with the entrance point of horizontally disposed neutron tof tube 3, the endpiece of neutron tof tube 3 is connected with the second slit arrangement 4, the rear side of the second slit arrangement 4 is provided with detector and shield assembly 5, except being provided with towards the second slit arrangement opening (width is slightly larger than diameter detector), shield assembly 5 wraps up detector fully, detector is connected with computing machine by multichannel time analyzer.Below the first slit arrangement 1, be provided with monitor 6 over against the neutron streaming direction, monitor 6 is connected with computing machine by multichannel time analyzer.Described the first slit arrangement 1, mechanical chopper 2, neutron tof tube 3, the second slit arrangement 4, detector and shield assembly 5 are installed on same bracing frame 8, and bracing frame 8 bottoms are connected by rotational drive motor 10 with first substrate 9.Described first substrate 9 is arranged on the horizontal slide rail 13 of second substrate 11, and is connected with pan drive motor 12 on second substrate 11.
From the neutron of cold neutron Beam Transport Systems, at first will be by the slit of the first slit arrangement 1, the size of slit is according to the two-dimensional of mechanical chopper, and the width adjustable extent of design is 1mm～20mm, and the height adjustable extent is 2mm～20mm.The first slit arrangement 1 below is provided with monitor 6, when being used for determining experiment measuring, and the stability of cold neutron line.
The width of the slit of the first slit arrangement 1 is manually adjusted with highly passing through, its structure as shown in Figure 3, multi-usage cold neutron quality of beam is measured with the first slit arrangement of flight time equipment identical with the structure of the second slit arrangement, and be known technology, include vertical adjustment knob 14, regulate the gap width between two vertical screen plate of material 16; Horizontal adjustment knob 15 is regulated the gap width between two blocks of horizontal shielding material plates 17.During experiment, the line situation of measuring as required, the two-dimentional yardstick of adjusting slit, experiment background and error when reducing spectral measurement.
By the continuous cold neutron streaming of the first slit arrangement, through after mechanical chopper 2, become pulse cold neutron line, the rotor of mechanical chopper 2 drives at the rotation with in surface perpendicular to the neutron streaming direction by chopper drive motor 7.The rotor of mechanical chopper is a kind of rotating disk of double-pore structure, as shown in Fig. 4-1, Fig. 4-2, comprise stainless steel annulus compressing tablet 18, stainless steel center compressing tablet 19, two line through hole 20 design sizes are that (or 2mm * 4mm), both sides are provided with stainless steel platen 21 and center cadmium plate 22 to 1mm * 2mm.Also be provided with optoelectronic switch on mechanical chopper, when the epitrochanterian line through hole of mechanical chopper passes through optoelectronic switch, photoelectric sensor triggered, produce trigger pip measuring period, the photoelectric sensor of optoelectronic switch is connected with multichannel time analyzer.In the present embodiment, the rotor design of mechanical chopper is of a size of diameter 300mm.The mechanical chopper rotor design is sandwich structure, and carries out dynamically balanced test and correction, makes the mass deviation of rotor on all directions less than 15g, can be under 7000rmp speed continuous working 12 hours.The Cross section Design of pulsed beam current is 1mm * 2mm (or 2mm * 4mm).Ideally, at rotor 5000rpm, namely during cycle 6ms, lift slide door exit, duct, CARR cooling in heap source fluence rate is about 8.815 * 10
10N/cm
2S, the individual pulse neutron number is about 2.4 * 10
4Individual.Lift slide door is the main block valve in reactor low-temperature receiver duct, during design, consider measurable maximum fluence rate (being neutron intensity) in its exit position, therefore, design available maximum impulse neutron number and adopt the Monte Carlo simulation data of carrying out spectral measurement in this position to calculate.
According to the actual installation situation of cold neutron Beam Transport Systems, but for guaranteeing measuring system cold neutron quality of beam parameter everywhere, the design flying distance is 1000mm to the maximum, and Whole Equipment length is about 1400mm.Under this length, the neutron of wavelength 2nm, the flight time is 5.056ms, corresponding mechanical chopper rotor speed 5934rpm.Consider that each spectrometer is different for the different wavelength range demand, therefore, rotor speed is set as 3000rpm, and (corresponding measurable neutron wavelength scope is that (0～1.695nm) is adjustable for 0～3.956nm)～7000rpm.
The pulse cold neutron line that penetrates by mechanical chopper enters neutron tof tube 3, and the neutron tof tube surrounds tubular construction by the aluminium flake of inwall brush gadolinium oxide material, and the diameter of entrance point is slightly less than the diameter of endpiece.During design, the length of neutron tof tube considers according to actual conditions and needed energy resolution.Do not wait because the present concrete support spacing of neutron guide tube is generally 1.4m to 2.6m, spectral measurement will cover whole conduit system, so when designing, 1.4m designs by minimum spacing.Consider the situation of whole equipment, design tof tube length is 1m.Simultaneously, by calculating, think and the length of 1m satisfy the demand of energy resolution fully (for typical 0.2nm neutron, energy resolution Δ E/E when wide in the 1mm hole, is about 6.1% left and right, Δ E/E=0.028*SQRT (E) * Δ t/L.Δ t wherein should comprise that pulsed beams time explanation, Measuring Time disperse, the time series analysis road is wide, electronics signal delay, Neutron Angular are dispersed the time error that causes and other time error.Because the time error that causes later can be ignored than the first three items error, only considered the Δ t of first three items here).
Before the cold neutron line arrives at detector, also will be by the second slit arrangement 4.Its design range of adjustment is: horizontal width 1mm～20mm, vertical height 2mm～20mm.Because the neutron number that arrives herein greatly reduces, so slit uses the manufacturing of Boron-containing-PE material.Its Main Function is that the cold neutron line of detector is incided in restriction, according to this design, only has incident angle could arrive detector lower than 5.2 ' neutron.
From gamma-rays, so probe designs is used due to the main interference of spectral measurement
3The He proportional counter tube.Whole detector is except in the face of the position of slit, will be wrapped in the detector shielding that the Boron-containing-PE material makes.Detector and shielding thereof can realize that perpendicular bisector take the rotor of mechanical chopper 2 is as axle, take the distance of rotor perpendicular bisector and detector as radius, near the center line of equipment ± 3 ° swing with interior, with the horizontal divergence angle distribution situation of detected neutron line.But the angular range of design horizontal hunting is ± 3 degree.Angle-resolved is 6.87min.
The fission chamber monitor is adopted in monitor 6 designs, be installed on the front portion of whole equipment, the below of the first slit arrangement 1, neutron guide tube outlet over against the cold neutron Beam Transport Systems, incide the neutron counting of monitor in order to measurement, the fission chamber monitor connects multichannel time analyzer after prime is amplified and screened, measuring to the multichannel time analyzer fixed number provides reference.
The fission chamber monitor is to be existing known equipment, and 3004 type U235 fission chamber monitors of U.S. LND INC company are adopted in design.Its principle is to utilize neutron and U235 to have an effect, fission reaction (closeness of U235 atom is quite low, only contains the U235 of 5mg in 3004 type monitors, reaches far away the critical value that chain reaction occurs) occurs, produce fission fragment, and make the gas in monitor ionize.Amplify and process by the electric signal that ionized gas is produced, will be converted to the electronics signal and export.
The electric signal that fission ionization monitor is exported amplifies (electronics amplification) and screens (filtering interfering) through prime again, is input to and carries out record in multichannel time analyzer.The 3004 type monitors that design is adopted, average every 10000 neutrons will be exported an electric signal.
Because the first slit arrangement 1, mechanical chopper 2, neutron tof tube 3, the second slit arrangement 4, detector and shield assembly 5 are installed on same bracing frame 8, bracing frame 8 bottoms are connected by rotational drive motor 10 with first substrate 9.During design, at the perpendicular bisector of mechanical chopper 2 rotors and the position of intersecting point of bracing frame 8, a horizontal bearing is installed, the tail end of bracing frame 8 (being the bottom of detector shielding) is installed two pulleys.Like this, the front portion of bracing frame 8 is connected with the first substrate 9 of mechanical chopper 2, chopper drive motor 7 and bottom by bearing, the rear portion is connected with first substrate 9 by pulley, having realized can be by motor or manual, the part of movable supporting frame more than 8, thus can realize the angular divergence distribution measuring of catheter section neutron streaming.In the present embodiment, the slewing area of bracing frame is set as ± and 3 °.And, for can also measuring guide the neutron horizontal distribution in cross section, first substrate 9 is arranged on the horizontal slide rail 13 of second substrate 11, and is connected with pan drive motor 12 on second substrate 11, make each device on first substrate can carry out the translation of horizontal direction.In the present embodiment, the mobile range of the horizontal slide rail of design is ± 10cm.
The composition of electronic system of the present invention as shown in Figure 2, mainly by the acquisition of signal of detector, monitor and obtain, the start signal of mechanical chopper rotor is obtained, the data of multichannel time analyzer process with the analysis and calculation machine data show, data storage and data analysis partly consist of.
Detector, monitor detect neutron signal and collect and pre-amplification through before putting, then through putting soon the nearly Gauss's of filtering shaping output waveform, enter into multichannel time analyzer through the negative NIM signal of constant fraction discriminator (CFD) accurate timing output again, the 584 type constant fraction discriminators of ORTEC are adopted in constant fraction discriminator (CFD) design.The neutron counting calibration of measuring take monitor is as prerequisite, and multichannel time analyzer measures take the photoelectric switching signal of mechanical chopper rotor as the cycle start signal detector signal that in each cycle, each time road receives.The corresponding one-period of start signal, when rotor rotated, perforate was every through optoelectronic switch, and the instantaneous start signal of sending of optoelectronic switch triggers the measurement in a new cycle.Multichannel time analyzer adds up the measurement result in each cycle and obtains a time spectrum that statistical error is less.
In specific design, can work as neutron counting that monitor measures and reach and trigger multichannel time analyzer after setting value and stop, also can using the set time to reach to trigger multichannel time analyzer after setting value to quit work.Computing machine reads the time spectrum on multichannel time analyzer, and is stored, and can also carry out some simple data analyses such as peak-seeking.Multichannel time analyzer is a kind of existing equipment, and the present embodiment is selected CDMCA type multichannel time analyzer.This multichannel time analyzer adopts the time as horizontal ordinate unit's (being) of counting, analysis ability with the highest 8192 roads, the single road the narrowest wide 5ns that reaches is (in reality, to use the 0.64us wide as the road), the single-channel count rate reaches as high as 100Kevents/s, analysis time scope: 80ns～10s, use the PCI integrated circuit board directly to be connected with computing machine, the operation interface close friend is intuitively.Data acquisition and process software are 32 softwares of Windows, can move on Windows Xp/2000 operating system.Following functions is by computer installation and control: measure/stop; Start channel, stop way are selected; The wide setting in hardware road; Metering system: " one stops together ", " several stops after one start " or " a lot of stop " more; " Timing measurement " or " fixed number is measured "; Measurement parameter: Measuring Time/1 tunnel tale; Wide, the total road number in road analysis time.The data of obtaining can store hard disk into by binary mode; File can be cut apart storage by " Measuring Time " or " file size "; The time spectrum that obtains can be preserved with binary mode automatically by " the file division time " selected.
Utilize the experiment flow of equipment provided by the present invention as follows:
At first, equipment is arranged on the end of neutron streaming transmission system to be measured, over against position to be measured.
Installation multichannel time analyzer on computers will receive the signal from three kinds of signal sources: detector, monitor and optoelectronic switch.During measurement, two kinds of working methods are arranged:
1. Timing measurement, can arrange Measuring Time (being accurate to 1ms);
2. fix a number and measure: with the pulse number calibration that monitor detects, the purpose that fixed number is measured is in order to eliminate the fluctuation of reactor power to the conforming impact of statistics between each time measurement.
Timing measurement is exactly (to be provided and calibrate foundation) multichannel time analyzer to be in measuring state in certain time interval by the multichannel time analyzer internal clock pulse, or set a value, receive the start signal number from 0 be accumulated to setting value during this period of time in multichannel time analyzer be in measuring state.The pulse number that fixed number measure to be exactly monitor is detected is used for calibration, sets a fixed number value, pulse number that monitor detects from 0 be accumulated to the fixed number value during this period of time in multichannel time analyzer be in measuring state.
First set working method during multichannel time analyzer work, then with " measurement " button on mouse click user interface, multichannel time analyzer namely is in measuring state.When the rotor of mechanical chopper rotates, when perforate process optoelectronic switch, the instantaneous start signal of sending of optoelectronic switch, trigger the measurement in a new cycle, the time of this start signal is decided to be the time zero in this cycle, and the road number of time spectrum and time road are wide is all preset before measuring (cycle=road number * time road is wide).Send start signal another perforate simultaneously at optoelectronic switch and put into a branch of neutron.Perforate is 1m to the constant distance of detector, and the neutron energy in pulsed beams is different, and its flying speed is also different, and the moment that arrives like this detector is also different.The neutron signal that detector receives is collected and pre-amplification through before putting, then through the main waveform of putting the nearly Gauss of filtering shaping output, enter into multichannel time analyzer through the negative NIM signal of discriminator accurate timing output again, the moment that multichannel time analyzer will be born the NIM signal and zero point in cycle, the mistiming between (signal that namely takes off constantly) was converted into corresponding time road number constantly, and counting that should correspondence time road number adds one.
Cycle is set time interval less than two start signals (if the cycle greater than the time interval of two start signals, stops fluctuation constantly and will make the data error that stops in the scope of fluctuation constantly can not be used too greatly due to what the fluctuation of rotor rotational frequency caused).The corresponding one-period of start signal, multichannel time analyzer adds up the measurement result in each cycle and obtains a time spectrum that statistical error is less.Multichannel time analyzer is real-time transmitted to computing machine with measurement result, and the time spectrum of measuring like this can be shown on computers in real time.
The detector maximum count rate that can accurately measure the detector signal moment (being that packing phenomenon does not occur between detector signal) is determined by the time constant of front putting.Due to signal delay time very little (ns magnitude), do not consider in the equipment nuclear electronics design of this flight time.The road that expection is set is several 8192, the wide 0.64 μ S in time road, the wide time error 1/8192=0.0122% that causes in road.
The below introduces the concrete measuring method of several application present devices:
1. cross section neutron horizontal distribution measuring method
Neutron horizontal distribution for the measuring guide cross section, flight time equipment can carry out integral translation, be about to rotor-support-foundation system, neutron tof tube, detector and the shielding design and installation thereof of the first and second slits, mechanical chopper on first substrate, this first substrate is arranged on second substrate by horizontal slide rail again.Mobile range by the design level slide rail is ± 10cm to realize the neutron horizontal distribution relative measurement to a plurality of neutron streamings cross section.Take CNGD (the Cold Neutron Guides D of system) as example, the neutron distribution degree of asymmetry of this beam cross section is:
Wherein, the neutron number of the x position that records for experiment of N (x).The resolution that cross section neutron horizontal distribution is measured is by the wide decision in the hole of rotor, and in the present invention, minimum is distinguished as 1mm.
2. neutron streaming horizontal angle in cross section is dispersed measuring method
For the angular divergence of measuring guide cross section neutron streaming distributes, flight time equipment can carry out whole deflection, be about to rotor-support-foundation system, neutron tof tube, detector and the shielding design and installation thereof of the first and second slits, mechanical chopper on same bracing frame, bracing frame can carry out horizontally rotating take the rotor vertical line as standard shaft with respect to first substrate, and slewing area is set as ± and 3 °.According to the design of the second slit, the angular resolution minimum of flight time equipment is 6.9 '.
Ideally, set identical Measuring Time, measure the same position place, the neutron number of the different angles in ± 3 °, then carry out normalization and calculate, the horizontal angle that can obtain this position line is dispersed distribution situation, with ε
1.5Be example:
ε
1.5Be the concentration degree situation of line in ± 1.5 ° of horizontal divergence angles, N (θ) is the number of neutron in the unit level angle.
3. the measuring method of lift slide door external neutrons transfer efficiency and signal to noise ratio (S/N ratio)
According to design, can also measure the transfer efficiency of cold neutron Beam Transport Systems out-pile part.Concrete measuring principle is:
Measure the cold neutron energy spectrum of lift slide door position and position to be measured
With
The joining gold foil activation measures the absolute fluence rate I of cold neutron line
0, the absolute fluence rate I of neutron streaming
1Respectively energy spectrum is carried out normalization, calculate the absolute power spectrum Ψ of cold neutron line of two positions, place
0(E) and Ψ
1(E):
The absolute power spectrum of line is carried out infinitesimal analysis calculate, can obtain in the different-energy scope of position to be measured, the transfer efficiency of the relative lift slide door of neutron streaming position, namely
In following formula, E
1And E
2Be respectively lower limit and the upper limit of energy range to be measured,
Be relative lift slide door position, position to be measured, to energy at E
1～E
2The transfer efficiency of neutron in scope.
The signal to noise ratio (S/N ratio) of position to be measured (ratio of required neutron and high-energy neutron) is neutron transfer efficiency in institute's energy requirement section and the ratio of high-energy neutron transfer efficiency, and take PNR spectrometer position as example, signal to noise ratio (S/N ratio) is:
Obviously, those skilled in the art can carry out various changes and modification and not break away from the spirit and scope of the present invention the present invention.Like this, if of the present invention these are revised and within modification belongs to the scope of claim of the present invention and equivalent technology thereof, the present invention also is intended to comprise these changes and modification interior.
Claims (10)
1. a multi-usage cold neutron quality of beam is measured the flight time equipment of using, it is characterized in that: comprise the first slit arrangement (1) that the cooling neutron streaming passes through, the rear side of the first slit arrangement (1) is provided with mechanical chopper (2), mechanical chopper (2) is connected with the entrance point of horizontally disposed neutron tof tube (3), the endpiece of neutron tof tube (3) is connected with the second slit arrangement (4), the rear side of the second slit arrangement (4) is provided with detector and shield assembly (5), detector is connected with computing machine by multichannel time analyzer.
2. multi-usage cold neutron quality of beam as claimed in claim 1 is measured the flight time equipment of using, it is characterized in that: the below in the first slit arrangement (1), be provided with monitor (6) over against the neutron streaming direction, monitor (6) is connected with computing machine by multichannel time analyzer.
3. multi-usage cold neutron quality of beam as claimed in claim 1 or 2 is measured the flight time equipment of using, it is characterized in that: described the first slit arrangement (1), mechanical chopper (2), neutron tof tube (3), the second slit arrangement (4), detector and shield assembly (5) are installed on same bracing frame (8), and bracing frame (8) bottom is connected by rotational drive motor (10) with first substrate (9).
4. multi-usage cold neutron quality of beam as claimed in claim 3 is measured the flight time equipment of using, it is characterized in that: described first substrate (9) is arranged on the horizontal slide rail (13) of second substrate (11), and is connected with pan drive motor (12) on second substrate (11).
5. multi-usage cold neutron quality of beam as claimed in claim 1 is measured the flight time equipment of using, it is characterized in that: the width adjustable extent of the slit of described the first slit arrangement (1) and the second slit arrangement (4) is 1～20mm, and the height adjustable extent is 2～20mm.
6. multi-usage cold neutron quality of beam as claimed in claim 1 is measured and used flight time equipment, it is characterized in that: the rotor of described mechanical chopper (2) drives at the rotation with in surface perpendicular to the neutron streaming direction by chopper drive motor (7).
7. multi-usage cold neutron quality of beam as claimed in claim 1 is measured and is used flight time equipment, and it is characterized in that: described neutron tof tube (3) is brushed with the aluminum pipe of gadolinium oxide material for inwall.
8. multi-usage cold neutron quality of beam as claimed in claim 1 is measured and is used flight time equipment, and it is characterized in that: described detector is
3The He proportional counter tube,
3The He proportional counter tube is arranged in the shield assembly (5) that the Boron-containing-PE material makes, and shield assembly (5) is provided with opening towards the second slit arrangement (4).
9. multi-usage cold neutron quality of beam as claimed in claim 2 is measured and used flight time equipment, it is characterized in that: described monitor (6) adopts the fission chamber monitor, is connected with multichannel time analyzer by wave-shaping circuit.
10. multi-usage cold neutron quality of beam as claimed in claim 6 is measured the flight time equipment of using, it is characterized in that: described mechanical chopper (2) is provided with optoelectronic switch, the epitrochanterian perforate of mechanical chopper produces trigger pip measuring period when passing through optoelectronic switch, and optoelectronic switch is connected with multichannel time analyzer.
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| CN109086555A (en) * | 2015-08-28 | 2018-12-25 | 易良碧 | Using the simulation spectrum curve emulation mode of Monte Carlo method |
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