CN103091701B - 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 Multipurpose flight time device for quality measurement of cold neutron beam.
Background technology
Cold neutron energy spectrum is one of basic parameter of neutron scattering experiment and reactor cold neutron source, is also one of important symbol weighing cold neutron Beam Transport Systems performance and cold neutron scattering experiment level.Generally abroad cold neutron power spectrum is measured, and the carrying out of not timing to detect before and after cold neutron spectrometer is installed, in the result write basic parameter in research centre and annual report.And the domestic current research work based on cold neutron spectral measurement aspect not yet had report, the surveying work of this aspect still belonged to blank in China.At the beginning of the 9's 0 of last century, China Atomic Energy Science Research Institute carries out HWRR reactor thermal neutron spectrum the earliest and surveys quantifier elimination, and have developed a set of easy time of flight arrangement.But the design of this device can not meet cold neutron scattering spectrometer to comprising beam level distribution, the measurement demand of line angular divergence distribution etc.China is greatly developing the Neutron scattering technology based on reactor and spallation neutron target at present, large quantities of high-quality, high-caliber cold neutron scattering spectrometer need be built, and cold neutron quality of beam is related to background, the key index such as efficiency and spatial discrimination of cold neutron scattering experiment, external relevant technical details is underground, and independent innovational design completes the development of technique to whole Neutron scattering technology and is significant.
Summary of the invention
The object of the invention is to the actual demand from cold neutron scattering spectrometer, a kind of light and practical flight time device for quality measurement of cold neutron beam is provided.
Technical scheme of the present invention is as follows: a kind of Multipurpose flight time device for quality measurement of cold neutron beam, comprise the first slit arrangement that 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, Multipurpose flight time device for quality measurement of cold neutron beam as above, wherein, in the below of the first slit arrangement, be just provided with monitor to neutron beam direction, monitor is connected with computing machine by multichannel time analyzer.
Further, Multipurpose flight time device for quality measurement of cold neutron beam as above, wherein, the first described slit arrangement, mechanical chopper, neutron tof tube, the second slit arrangement, detector and shield assembly are installed on same bracing frame, and bracing frame bottom is connected by rotational drive motor with first substrate.
Further, Multipurpose flight time device for quality measurement of cold neutron beam as above, wherein, described first substrate is arranged on the horizontal slide rail of second substrate, and is connected with the pan drive motor on second substrate.
Further, Multipurpose flight time device for quality measurement of cold neutron beam as above, wherein, the width-adjustable scope of the first described slit arrangement and the slit of the second slit arrangement is 1 ~ 20mm, and height adjustable scope is 2 ~ 20mm.
Further, Multipurpose flight time device for quality measurement of cold neutron beam as above, wherein, the rotor of described mechanical chopper is driven at the rotation with in surface perpendicular to neutron streaming direction by chopper drive motor.
Further, Multipurpose flight time device for quality measurement of cold neutron beam as above, wherein, described neutron tof tube is the aluminum pipe that inwall is brushed with gadolinium oxide material.
Further, Multipurpose flight time device for quality measurement of cold neutron beam as above, wherein, described detector is
3he proportional counter tube,
3he proportional counter tube is arranged in the shield assembly that Boron-containing-PE material makes, and shield assembly is provided with opening towards the second slit arrangement.
Further, Multipurpose flight time device for quality measurement of cold neutron beam as above, wherein, described monitor adopts fission chamber monitor, is connected with multichannel time analyzer through wave-shaping circuit.
Further, Multipurpose flight time device for quality measurement of cold neutron beam as above, wherein, described mechanical chopper is provided with optoelectronic switch, the epitrochanterian perforate of mechanical chopper produces trigger pip measuring period through optoelectronic switch, and optoelectronic switch is connected with multichannel time analyzer.
Beneficial effect of the present invention is as follows: Multipurpose flight time device for quality measurement of cold neutron beam provided by the present invention adopts relatively simple pulsed-beam time-of-flight methods and unique Machine Design, motor is coordinated to drive one-piece construction, control translation and the rotation of finishing equipment, realize the measurement of cold neutron power spectrum and line parameters simultaneously.Compared with public technology in the world, advantage of the present invention is delicate structure, give full play to computer software advantage, significantly reduce hardware cost, coordinated complicated motion by software and hardware, whole system is simpler and easy stable, achieves the corner location of pinpoint accuracy and opens braking fast, consider cold neutron Beam Transport Systems specific design situation simultaneously, fully can meet the demand that each cold neutron spectrometer is measured for energy spectrum and Q factor.
Accompanying drawing explanation
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 is 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, Multipurpose flight time device for quality measurement of cold neutron beam provided by the present invention, comprise the first slit arrangement 1 that 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 except opening (width is slightly larger than diameter detector) towards the second slit arrangement, shield assembly 5 wraps up detector completely, detector is connected with computing machine by multichannel time analyzer.In the below of the first slit arrangement 1, be just provided with monitor 6 to neutron beam direction, monitor 6 is connected with computing machine by multichannel time analyzer.The first described slit arrangement 1, mechanical chopper 2, neutron tof tube 3, 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.Described first substrate 9 is arranged on the horizontal slide rail 13 of second substrate 11, and is connected with the pan drive motor 12 on second substrate 11.
From the neutron of cold neutron Beam Transport Systems, first by the slit by the first slit arrangement 1, the size of slit is according to the two-dimensional of mechanical chopper, and the width-adjustable scope of design is 1mm ~ 20mm, and height adjustable scope is 2mm ~ 20mm.Monitor 6 is provided with below first slit arrangement 1, during for determining experiment measuring, the stability of cold neutron line.
The width of the slit of the first slit arrangement 1 and highly manually adjusting, its structure as shown in Figure 3, first slit arrangement of Multipurpose flight time device for quality measurement of cold neutron beam is identical with the structure of the second slit arrangement, and be known technology, include vertical adjustment knob 14, regulate the gap width between two pieces of vertical screen plate of material 16; Horizontal adjustment knob 15, regulates the gap width between two pieces of debris shield plate of material 17.During experiment, the line situation measured as required, regulates the two-dimentional yardstick of slit, experiment background during reduction spectral measurement and error.
By the continuous cold neutron streaming of the first slit arrangement, after mechanical chopper 2, become pulse cold neutron line, the rotor of mechanical chopper 2 is driven at the rotation with in surface perpendicular to 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 1mm × 2mm (or 2mm × 4mm), and both sides are provided with stainless steel platen 21 and center cadmium plate 22.Mechanical chopper is also provided with optoelectronic switch, and the epitrochanterian line through hole of mechanical chopper, through optoelectronic switch, makes photoelectric sensor trigger, and 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.Mechanical chopper rotor design is sandwich structure, the test of action balance of going forward side by side and correction, makes the mass deviation of rotor in all directions be less than 15g, can continuous working 12 hours under 7000rmp speed.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, CARR cooling in heap source aperture road fluence rate is about 8.815 × 10
10n/cm
2s, then 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 that measurable maximum fluence rate (i.e. neutron intensity) is 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, for ensure can measuring system cold neutron quality of beam parameter everywhere, 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 different wavelength range demand, therefore, rotor speed is set as 3000rpm (corresponding measurable neutron wavelength scope is 0 ~ 3.956nm) ~ 7000rpm (0 ~ 1.695nm) is adjustable.
The pulse cold neutron line penetrated by mechanical chopper enters neutron tof tube 3, and 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 required energy resolution.Concrete support spacing due to current neutron guide tube is not generally 1.4m to 2.6m not etc., and spectral measurement will cover whole conduit system, when therefore designing, design by minimum spacing 1.4m.Consider the situation of whole equipment, design flight-tube lengths is 1m.Meanwhile, by calculating, thinking and the length of 1m meeting the demand of energy resolution completely (for typical 0.2nm neutron, energy resolution Δ E/E, when 1mm hole is wide, is about about 6.1%, Δ E/E=0.028*SQRT (E) × Δ t/L.Δ t wherein should comprise pulsed beams time explanation, Measuring Time dispersion, time series analysis road is wide, electrical signal postpones, Neutron Angular disperses the time error and other time error that cause.Due to the time error that causes below comparatively first three items error can ignore, only considered the Δ t of first three items here).
Before cold neutron line arrives at detector, also will by the second slit arrangement 4.Its design range of adjustment is: horizontal width 1mm ~ 20mm, vertical height 2mm ~ 20mm.Because the neutron number arrived herein greatly reduces, therefore slit uses the manufacture of Boron-containing-PE material.Its Main Function is the cold neutron line that detector is incided in restriction, according to this design, only have incident angle lower than 5.2 ' neutron could arrive detector.
Because the main interference of spectral measurement is from gamma-rays, therefore probe designs uses
3he proportional counter tube.Whole detector, except except the position of slit, will be wrapped in detector shielding that Boron-containing-PE material makes.Detector and shielding thereof can realize with the perpendicular bisector of the rotor of mechanical chopper 2 as axle, with the distance of rotor perpendicular bisector and detector for radius, swing, with the horizontal divergence angle distribution situation of detected neutron line within approximate centerline ± 3 of equipment °.Design can the angular range of horizontal hunting be ± 3 degree.Angle-resolved is 6.87min.
Monitor 6 design adopts fission chamber monitor, be installed on the front portion of whole equipment, the below of the first slit arrangement 1, just the neutron guide tube of cold neutron Beam Transport Systems is exported, in order to measure the neutron counting inciding monitor, fission chamber monitor amplifies through prime and after examination, connects multichannel time analyzer, provide reference to the measurement of multichannel time analyzer fixed number.
Fission chamber monitor is existing known device, and design adopts 3004 type U235 fission chamber monitors of LND INC company of the U.S..Its principle utilizes neutron and U235 to have an effect, there is fission reaction (closeness of U235 atom is quite low, the U235 only containing 5mg in 3004 type monitors, reaches far away the critical value that chain reaction occurs), produce fission fragment, and the gas in monitor is ionized.Amplified by the electric signal produced ionized gas and process, electrical signal will be converted to and export.
The electric signal that fission ionization monitor exports amplifies (electronics amplification) through prime again and screens (filtering interfering), is input in multichannel time analyzer and carries out record.The 3004 type monitors that design adopts, on average every 10000 neutrons, by output electric signal.
Because the first slit arrangement 1, mechanical chopper 2, neutron tof tube 3, second slit arrangement 4, detector and shield assembly 5 are installed on same bracing frame 8, bracing frame 8 bottom is connected by rotational drive motor 10 with first substrate 9.During design, at the perpendicular bisector of mechanical chopper 2 rotor and the position of intersecting point of bracing frame 8, install a horizontal bearing, the tail end (i.e. the bottom of detector shielding) of bracing frame 8 installs two pulleys.Like this, the front portion of bracing frame 8 is connected by the first substrate 9 of bearing and mechanical chopper 2, chopper drive motor 7 and bottom, rear portion is connected with first substrate 9 by pulley, to achieve by motor or manually, the part of movable supporting frame more than 8, thus the angular divergence distribution measuring that can realize catheter section neutron streaming.In the present embodiment, the slewing area of bracing frame is set as ± 3 °.And, in order to can also the neutron horizontal distribution in measuring guide cross section, first substrate 9 is arranged on the horizontal slide rail 13 of second substrate 11, and is connected with the 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.
As shown in Figure 2, the start signal primarily of the acquisition of signal of detector, monitor and acquisition, mechanical chopper rotor obtains the composition of electronic system of the present invention, the data process&analysis of multichannel time analyzer and computer data display, data store and data analysis component is formed.
Detector, monitor detect premenstrual the putting of neutron signal and collect and pre-amplification, then the waveform of nearly Gauss is exported through putting filtering shaping soon, export negative NIM signal through constant fraction discriminator (CFD) accurate timing again and enter into multichannel time analyzer, constant fraction discriminator (CFD) design adopts the 584 type constant fraction discriminators of ORTEC.By monitor measure neutron counting calibration premised on, multichannel time analyzer with the photoelectric switching signal of mechanical chopper rotor for cycle start signal measures the detector signal that in each cycle, each time road receives.A corresponding one-period of start signal, during rotor turns, perforate is often through optoelectronic switch, and optoelectronic switch is instantaneous sends start signal, triggers the measurement in a new cycle.Multichannel time analyzer adds up the measurement result in each cycle and obtains the less time spectrum of a statistical error.
In specific design, can work as monitor measure neutron counting reach setting value after trigger multichannel time analyzer stop, triggering multichannel time analyzer after the set time also can be used to reach setting value and 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 selects CDMCA type multichannel time analyzer.This multichannel time analyzer adopts the time as the abscissa unit (i.e. road) of counting, there is the analysis ability in the highest 8192 roads, the single road the narrowest wide 5ns that reaches is (in reality, 0.64us will be used) wide as road, single-channel count rate reaches as high as 100Kevents/s, analysis time scope: 80ns ~ 10s, uses PCI board to be directly connected with computing machine, and operation interface close friend is intuitively.Data acquisition and process software are Windows 32 softwares, can run in 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 " stopping a lot of " more; " Timing measurement " or " fixed number measurement "; Measurement parameter: Measuring Time/1 tunnel tale; Wide, the total number of channels in road analysis time.The data obtained can be stored into hard disk by binary mode; File can store by " Measuring Time " or " file size " segmentation; The time spectrum obtained can be preserved " file division time " selectively in a binary fashion automatically.
Utilize the experiment flow of equipment provided by the present invention as follows:
First, equipment is arranged on the end of neutron streaming transmission system to be measured, is just treating location and putting.
The signal that multichannel time analyzer on computers will receive from three kinds of signal sources is installed: detector, monitor and optoelectronic switch.During measurement, there are two kinds of working methods:
1. Timing measurement, can arrange Measuring Time (being accurate to 1ms);
2. fixed number measurement: the pulse number calibration detected with monitor, the object that fixed number is measured is in order to the fluctuation of eliminative reaction heap heap power adds up conforming impact between each measurement.
Timing measurement is exactly in certain time interval, (provided by multichannel time analyzer internal clock pulse and calibrate foundation) multichannel time analyzer to be in measuring state, or a setting value, receive start signal number from 0 be accumulated to setting value during this period of time in multichannel time analyzer be in measuring state.Fixed number is measured the pulse number detected by monitor exactly and is used for calibration, sets a fixed number value, the pulse number detected at monitor from 0 be accumulated to 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 click " measurement " button on user interface with mouse, namely multichannel time analyzer is in measuring state.During the rotor turns of mechanical chopper, when perforate is through optoelectronic switch, optoelectronic switch is instantaneous sends start signal, trigger the measurement in a new cycle, the time of this start signal is decided to be the time zero in this cycle, the number of channels of time spectrum and time road wide be all measure before preset (cycle=number of channels × 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 arriving detector is like this also different.The neutron signal that detector receives is premenstrual puts collection and pre-amplification, then put through main the waveform that filtering shaping exports nearly Gauss, export negative NIM signal through discriminator accurate timing again and enter into multichannel time analyzer, mistiming between the moment of this negative NIM signal with moment zero point in cycle (namely taking off the signal moment) is converted into corresponding time number of channels by multichannel time analyzer, then the counting of this correspondence time number of channels adds one.
Cycle set is less than the time interval (if the cycle is greater than the time interval of two start signals, the data error made within the scope of stop timing fluctuation can not be used too greatly by the fluctuation of the stop timing caused due to rotor turns frequency occupancy) of two start signals.A corresponding one-period of start signal, multichannel time analyzer adds up the measurement result in each cycle and obtains the less time spectrum of a statistical error.Measurement result is real-time transmitted to computing machine by multichannel time analyzer, and the time spectrum measured like this can be shown on computers in real time.
The detector maximum count rate accurately can measuring the detector signal moment (namely packing phenomenon not occurring 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 design of this flight time device nuclear electronics.The number of channels 8192 of expection setting, the wide 0.64 μ S in time road, the wide time error 1/8192=0.0122% caused in road.
Introduce the concrete measuring method of several application present device below:
1. cross section neutron horizontal distribution measuring method
For the neutron horizontal distribution in measuring guide cross section, flight time device can carry out integral translation, by the rotor-support-foundation system of the first and second slits, mechanical chopper, neutron tof tube, detector and shielding design and installation thereof on the first substrate, this first substrate is arranged on second substrate by horizontal slide rail again.Be ± 10cm by the mobile range of design level slide rail, the neutron horizontal distribution relative measurement to multiple neutron streaming cross section can be realized.For CNGD (Cold Neutron Guides system D), the neutron distribution degree of asymmetry of this beam cross section is:
Wherein, N (x) is the neutron number of testing the x position recorded.The resolution that cross section neutron horizontal distribution is measured, by the wide decision in the hole of rotor, in the present invention, is minimumly distinguished as 1mm.
2. neutron streaming horizontal angle in cross section disperses measuring method
For the angular divergence of measuring guide cross section neutron streaming distributes, flight time device can carry out entirety deflection, by the rotor-support-foundation system of the first and second slits, mechanical chopper, neutron tof tube, detector and shielding design and installation thereof on same bracing frame, relative to first substrate, can to carry out with rotor vertical line be standard shaft to bracing frame horizontally rotates, slewing area is set as ± and 3 °.According to the design of the second slit, the angular resolution of flight time device is minimum is 6.9 '.
Ideally, set identical Measuring Time, measure same position place, the neutron number of the different angles in ± 3 °, then be normalized calculating, the horizontal angle that can obtain this position line disperses distribution situation, with ε
1.5for 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 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, the transfer efficiency of cold neutron Beam Transport Systems out-pile part can also be measured.Concrete measuring principle is:
Measure the cold neutron energy spectrum of lift slide door position and position to be measured
with
in conjunction with gold foil activation method, measure and obtain the absolute fluence rate I of cold neutron line
0, the absolute fluence rate I of neutron streaming
1.Respectively energy spectrum is normalized, calculates the absolute power spectrum Ψ of cold neutron line of two positions, place
0and Ψ (E)
1(E):
Infinitesimal analysis calculating is carried out to the absolute power spectrum of line, can obtain within the scope of the different-energy of position to be measured, the transfer efficiency of the relative lift slide door position of neutron streaming, namely
In above formula, E
1and E
2be respectively lower limit and the upper limit of energy range to be measured,
for 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) (ratio of required neutron and high-energy neutron) of position to be measured is then the ratio of the Neutron Transmission efficiency in institute's energy requirement section and high-energy neutron transfer efficiency, and for PNR spectrometer position, signal to noise ratio (S/N ratio) is:
Obviously, those skilled in the art can carry out various change and modification to the present invention and not depart from the spirit and scope of the present invention.Like this, if belong within the scope of the claims in the present invention and equivalent technology thereof to these amendments of the present invention and modification, then the present invention is also intended to comprise these change and modification.
Claims (7)
1. a Multipurpose flight time device for quality measurement of cold neutron beam, it is characterized in that: comprise the first slit arrangement (1) that 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, in the below of the first slit arrangement (1), just monitor (6) is provided with to neutron beam 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) bottom is 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 the pan drive motor (12) on second substrate (11).
2. Multipurpose flight time device for quality measurement of cold neutron beam as claimed in claim 1, it is characterized in that: the width-adjustable scope of described the first slit arrangement (1) and the slit of the second slit arrangement (4) is 1 ~ 20mm, and height adjustable scope is 2 ~ 20mm.
3. Multipurpose flight time device for quality measurement of cold neutron beam as claimed in claim 1, is characterized in that: the rotor of described mechanical chopper (2) is driven at the rotation with in surface perpendicular to neutron streaming direction by chopper drive motor (7).
4. Multipurpose flight time device for quality measurement of cold neutron beam as claimed in claim 1, is characterized in that: described neutron tof tube (3) is brushed with the aluminum pipe of gadolinium oxide material for inwall.
5. Multipurpose flight time device for quality measurement of cold neutron beam as claimed in claim 1, is characterized in that: described detector is
3he proportional counter tube,
3he proportional counter tube is arranged in the shield assembly (5) that Boron-containing-PE material makes, and shield assembly (5) is provided with opening towards the second slit arrangement (4).
6. Multipurpose flight time device for quality measurement of cold neutron beam as claimed in claim 1, is characterized in that: described monitor (6) adopts fission chamber monitor, is connected with multichannel time analyzer by wave-shaping circuit.
7. Multipurpose flight time device for quality measurement of cold neutron beam as claimed in claim 3, 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 through optoelectronic switch, and optoelectronic switch is connected with multichannel time analyzer.
Priority Applications (1)
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| CN104376890B (en) * | 2014-10-30 | 2017-05-24 | 东莞中子科学中心 | Rotating disc type neutron chopper |
| CN109086555B (en) * | 2015-08-28 | 2022-04-19 | 易良碧 | Simulation method for simulating energy spectrum curve by adopting Monte Carlo method |
| CN105445780B (en) * | 2015-11-10 | 2018-11-30 | 中国原子能科学研究院 | A kind of measuring device and method of neutron monochromator higher hamonic wave |
| CN105388169B (en) * | 2015-11-10 | 2018-11-30 | 中国原子能科学研究院 | Neutron beam filter strainability measuring device and method |
| CN105319575A (en) * | 2015-12-04 | 2016-02-10 | 中国原子能科学研究院 | Neutron performance testing device of neutron collimator |
| CN108538421B (en) * | 2018-04-17 | 2019-05-17 | 东莞理工学院 | A kind of diaphragm of rotating disc type |
| CN117214944B (en) * | 2023-11-09 | 2024-02-09 | 山东大学 | Slow neutron detection structure and method for measuring slow neutron energy spectrum |
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