The regulating device of neutron reflection spectrometer monochromator and adjust the method for monochromator with it
Technical field
The present invention relates to a kind of regulating device of the neutron reflection spectrometer monochromator with horizontal sample how much and with its method of adjusting monochromator, belong to the neutron reflection technical field.
Background technology
The neutron reflection technology is a branch of the neutron scattering technology that grows up in the beginning of the eighties, mid-term, has become a kind of strong means of surveying 0.1nm-100nm scope inside surface and interfacial structure.Neutron reflection Technology Need wavelength is λ, and bandwidth is the monochromatic neutron beam of Δ λ.The neutron that reactor provides all has continuous power spectrum usually, and this neutron source is called white light neutron source.The crystal that obtains monochromatic neutron beam with the Bragg reflection from white light neutron source is called crystal monochromator.The white light neutron source of drawing when reactor is with θ
MWhen the crystal face of angle and crystal (hkl) intersects, according to the Bragg law, the wavelength X of reflecting bundle and interplanar distance d
Hkl, scattering angle 2 θ
MBetween the pass be: λ=2d
HklSin θ
MSelect different interplanar distance d
HklOr incident angle θ
MCan obtain the monochromatic neutron beam of different wave length.In the neutron reflection experiment, the most frequently used crystal monochromator is the highly oriented pyrolytic graphite monochromator of crystal face (002) orientation.Therefore, to satisfy the neutron beam that required wavelength X is tested in neutron reflection in order from white light neutron source, obtaining, to need to regulate the angle theta between white light neutron source and the monochromator
M
The neutron reflection technology is by measuring the sample reflectivity with Scattering of Vector Q (the Scattering of Vector Q=4 π sin θ/λ of vertical sample direction, wherein λ is the wavelength of neutron beam, θ is that the incident angle of neutron beam is the angle of neutron beam and sample surfaces) variation relation, reflection scattering length density is along the distribution of vertical sample direction, by analyzing the information such as roughness that reflectance curve obtains thickness of sample, scattering length density, surface and interface.Ji He difference per sample, neutron reflection spectrometer can be divided into the neutron reflection spectrometer with how much of horizontal samples usually and have two kinds of the neutron reflection spectrometers of vertical sample geometry.Neutron reflection spectrometer with how much in vertical sample is applicable to the measurement of solid sample, the variation that can keep the motionless realization incident angle of monochromator by the rotation solid sample, thereby the regulating device of its monochromator is fairly simple.Neutron reflection spectrometer with horizontal sample geometry is not only applicable to the measurement of solid sample, is applicable to the measurement of fluid sample yet.Because the surface of liquid can only keep surface level under the gravity effect, therefore can not realize the variation of incident angle by rotation or inclination sample.Therefore, for the neutron reflection spectrometer with horizontal sample geometry, be to obtain Scattering of Vector variation delta Q, the incident angle of neutron beam need change Δ θ, needs the inclination crystal monochromator to depart from its plane of reflection Δ θ/2 jiaos of neutron beams that neutron reflection experiment usefulness is provided.
In addition, the scattering length density of liquid is lower, cause the neutron reflection critical angle less, and reflectivity is lower, needs high-intensity neutron beam.For improving the used neutron beam intensity of neutron reflection experiment, improve testing efficiency, under the certain situation of white light neutron source flux, need the intercepting white light neutron source of maximum magnitude, therefore need accurately to adjust the geometric center of crystal monochromator and the relative position of white light neutron source.
At present domestic not about the report of the monochromator regulating device of neutron reflection spectrometer with how much of horizontal samples.State-of-the-art in the world is how much neutron reflection spectrometers of horizontal sample in USA National Institute of Standard and Technology (National Institute of Standards and Technology) neutron research centre, but does not retrieve the monochromator regulating device of this spectrometer use and the open report of method.
Summary of the invention
The purpose of this invention is to provide a kind of regulating device of the neutron reflection spectrometer monochromator with horizontal sample how much and adjust the method for monochromator with it.
Regulating device with neutron reflection spectrometer monochromator of horizontal sample geometry provided by the invention comprises back-up block, pedestal, accurate angle displacement platform, accurate universal stage, precision level displacement platform and the precise height displacement platform that supports monochromator; Described accurate angle displacement platform by holder a and with can forming along the accurate angle displacement arc table top that the arc track of described holder a is swung that described holder a flexibly connects; Described accurate universal stage is made up of with the rotatable accurate rotary table top that is arranged on the described holder b holder b; Described precision level displacement platform is made up of with the precision level displacement table top that moves horizontally that is arranged on the described holder c holder c; Described precise height displacement platform is made up of with the liftable precise height displacement table top that is arranged on the described holder d holder d; Described back-up block is located on the described pedestal; Described pedestal is located on the described accurate angle displacement arc table top, and described holder a is located on the described accurate rotary table top, and described holder b is located on the described precision level displacement table top, and described holder c is located on the described precise height displacement table top.
In the above-mentioned regulating device, the plane of incidence of described monochromator and surface level are at an angle of 90; The geometric center of described monochromator equals the pivot center of described accurate angle displacement platform to the height of described accurate angle displacement arc table top to the height of the bottom surface of described pedestal; The axis of rotation of described accurate rotary table top is by the geometric center of described monochromator; The axis of described precision level displacement platform and the axis of rotation of described accurate rotary table top intersect vertically; The median vertical line of described precise height displacement platform overlaps with the axis of rotation of described accurate rotary table top, and the axis of the median vertical line of described precise height displacement platform and described precision level displacement platform intersects vertically.
In the above-mentioned regulating device, the accurate angle displacement arc table top of described accurate angle displacement platform links to each other with the stepper motor that can drive this precision angle displacement arc table top rotation by rotating mechanism; Described rotating mechanism can be existing any mechanism that can realize rotating function.
In the above-mentioned regulating device, the accurate rotary table top of described accurate universal stage links to each other with the stepper motor that can drive this precision rotary table top rotation by rotating mechanism; Described rotating mechanism can be existing any mechanism that can realize spinfunction.
In the above-mentioned regulating device, the precision level displacement table top of described precision level displacement platform links to each other with the stepper motor that can drive this precision level displacement table-surface level displacement by travel mechanism; Described travel mechanism can be existing any mechanism that can realize locomotive function.
In the above-mentioned regulating device, the precise height displacement table top of described precise height displacement platform links to each other with the stepper motor that can drive this precise height displacement table top lifting by elevating mechanism; Described elevating mechanism can be existing any mechanism that can realize elevating function.
In the above-mentioned regulating device, the angle precision of described accurate angle displacement platform can be ± and 0.0015 °.
In the above-mentioned regulating device, the angle precision of described accurate universal stage can be ± and 0.005 °.
In the above-mentioned regulating device, the bearing accuracy of described precision level displacement platform can be ± 3 μ m.
In the above-mentioned regulating device, the bearing accuracy of described precise height displacement platform can be ± 3 μ m.
In the above-mentioned regulating device, described monochromator can be the highly oriented pyrolytic graphite monochromator, as the highly oriented pyrolytic graphite monochromator of crystal face (002) orientation.
In the above-mentioned regulating device, can test the needs of neutron beam intensity and white light neutron source line area that reactor is drawn according to neutron reflection, can be made as a plurality of described monochromator or many groups.
The present invention also provides the method for utilizing above-mentioned regulating device to adjust monochromator, comprises the steps:
(1) regulates described precise height displacement table top and precision level displacement table top, the geometric center of described monochromator is overlapped with the center of white light neutron source;
(2) the accurate rotary table top with described accurate universal stage rotates around described axis of rotation, and keeps the geometric center invariant position of described monochromator;
(3) the accurate angle displacement arc table top with described accurate angle displacement platform rotates around described pivot center, and keeps the geometric center invariant position of described monochromator, then obtains the monochromatic neutron beam of different angles.
Regulating device provided by the invention has the structure of simple and reliable space geometry relation, can clearly carry out the selection of wavelength and the change of monochromatic neutron beam angle, and the bearing accuracy height is easy to obtain high-intensity neutron beam; Method of adjustment provided by the invention is simple.
Description of drawings
Fig. 1 is the structural representation of regulating device of the present invention.
Fig. 2 is the structural representation of the use state of regulating device of the present invention.
Each mark is as follows among the figure: 1 highly oriented pyrolytic graphite monochromator, 2 back-up blocks, 3 pedestals, 4 accurate angle displacement arc table tops, 5 holder a, 6 accurate rotary table tops, 7 holder b, 8 precision level displacement table tops, 9 holder c, 10 precise height displacement table tops, 11 holder d.
Embodiment
The present invention will be further described below in conjunction with embodiment, but the present invention is not limited to following examples.
As shown in Figure 1, the regulating device of present embodiment comprises back-up block 2, pedestal 3, accurate angle displacement platform (angle precision is for ± 0.0015 °), accurate universal stage (angle precision is for ± 0.005 °), precision level displacement platform (bearing accuracy is ± 3 μ m) and the precise height displacement platform (bearing accuracy is ± 3 μ m) of the highly oriented pyrolytic graphite monochromator 1 of vertical support crystal face (002) orientation; Accurate angle displacement platform by holder a5 and with can forming along the accurate angle displacement arc table top 4 that the arc track of holder a5 is swung of flexibly connecting along this holder a5, accurate angle displacement arc table top 4 is connected with the stepper motor (not shown) of crossing that can drive its rotation by rotating mechanism, is used for regulating rotational angle; Accurate universal stage is made up of with the rotatable accurate rotary table top 6 that is arranged on this holder b7 holder b7, accurate rotary table top 6 is connected with the stepper motor (not shown) that can drive its rotation by rotating mechanism, is used for regulating the anglec of rotation; Precision level displacement platform is made up of with the precision level displacement table top 8 that moves horizontally that is arranged on this holder c9 holder c9, precision level displacement table top 8 by displacement mechanism with can drive its stepper motor (not shown) that moves horizontally and be connected, be used for regulating horizontal shift; Precise height displacement platform is made up of with the liftable precise height displacement table top 10 that is arranged on this holder d11 holder d11, precise height displacement table top 10 is connected with the stepper motor (not shown) that can drive its lifting by elevating mechanism, is used for regulating height; Back-up block 2 is located on 3 pedestals; Pedestal 3 is rigidly secured on the accurate angle displacement arc table top 4, the geometric center O ' of monochromator 1 equals the pivot center of accurate angle displacement platform to the height of accurate angle displacement arc table top 4 to the height of the bottom surface of pedestal 3, guarantees that the pivot center CC ' of accurate angle displacement platform is by the horizontal central line AA ' of highly oriented pyrolytic graphite monochromator 1; Holder a5 is rigidly secured on the accurate rotary table top 6, and the axis of rotation DD ' of accurate rotary table top 6 is by the geometric center O ' of monochromator 1; Holder b7 is fixed on the precision level displacement table top 8, and the axis EE ' of precision level displacement platform and the axis of rotation DD ' of accurate rotary table top 6 intersect vertically; Holder c9 is fixed on the precise height displacement table top 10, the z direction median vertical line FF ' of precise height displacement platform overlaps with the axis of rotation DD ' of accurate rotary table top 4, and the z direction median vertical line FF ' of precise height displacement platform and the axis EE ' of precision level displacement platform intersect vertically; Holder d11 is installed on the how much neutron reflection spectrometer (not shown)s, makes the axis EE ' of precision level displacement platform along the x direction of principal axis.
In the above-mentioned regulating device, monochromator can also be germanium single crystal neutron monochromator or beryllium single crystal neutron monochromator; The angle precision of accurate angle displacement platform 4 and accurate universal stage 5 can be regulated as required; The bearing accuracy of precision level displacement platform 6 and precise height displacement platform 7 can be regulated as required; Rotating mechanism, rotating mechanism, displacement mechanism and elevating mechanism can be respectively and existingly can realize rotating, rotate, move horizontally any mechanism with elevating function.
When using above-mentioned regulating device, as shown in Figure 2, at first move precise height displacement platform 7 and precision level displacement platform 6, the geometric center O ' that regulates monochromator 1 overlaps with the center O of white light neutron source;
Give the stepper motor energising of precise height displacement platform 7, the accurate closely-pitched lead screw that drives precise height displacement platform 7 rotate and with accurate closely-pitched lead screw nut engaged and down wedge move, thereby drive with following wedge with the last wedge of inclined-plane precision-fit and highly the mobile working table top move up and down.The scrambler that is installed in the stepper motor afterbody of precise height displacement platform 7 is directly measured rotational angle, obtain the actual displacement amount of precise height displacement platform 7 by the geometric relationship of calculating accurate closely-pitched leading screw pitch dimension and inclined-plane, bearing accuracy is ± 3 μ m;
Give the stepper motor energising of precision level displacement platform 6 simultaneously, the ball-screw that drives precision level displacement platform 6 rotates and moves horizontally with ball-screw nut engaged and horizontal shift work top.The grating chi that is installed in the side of precision level displacement platform 6 is directly measured horizontal displacement, and bearing accuracy is ± 3 μ m;
Next moves accurate universal stage 5;
Obtain white light neutron source and the angle theta M=45 of highly oriented pyrolytic graphite monochromator 1 in surface level ° according to the Bragg law, i.e. the monochromatic neutron beam wavelength that after monochromator 1 reflection, takes off
With the angle of white light neutron source be 2 θ
M=90 °;
Give the stepper motor energising of accurate universal stage 5, drive the over-type worm gear of accurate universal stage 5, cause that the rotary work table top of accurate universal stage 5 and the accurate angle displacement platform 4 that is installed on it, pedestal 3, back-up block 2, monochromator 1 are around the axis of rotation DD ' rotation of rotary work table top.The scrambler that is installed in the stepper motor afterbody of accurate universal stage 5 is directly measured corner, through worm and wormwheel 1: 180 reduction gear ratio, obtains the actual rotational angle of rotary work table top, and angle precision can reach ± and 0.005 °;
Move accurate angle displacement platform 4 at last, the angle that offers the monochromatic neutron beam of neutron reflection experiment usefulness changes in θ=-10 °~10 ° of scopes, and concrete adjustment process is as follows:
The tilting table face of accurate
angle displacement platform 4 keeps level, and the axis of rotation DD ' of the rotary work table top of accurate
universal stage 5 is by the vertical center line BB ' of monochromator, and as shown in Figure 1, reflection is known according to minute surface, the wavelength after monochromator 1 reflection
The flight of the parallel x axle of monochromatic neutron beam, i.e. θ=0 °; Monochromator 1 is around the pivot center CC ' rotation Δ θ of accurate
angle displacement platform 4=-5 °, and the monochromatic neutron beam angle after monochromator 1 reflection changes 2 Δ θ=-10 °; When monochromator 1 around the pivot center CC ' rotation Δ θ of accurate
angle displacement platform 4=5 °, the monochromatic neutron beam angle after monochromator 1 reflection changes 2 Δ θ=10 °.Monochromator 1 is around the pivot center CC ' rotation Δ θ angle of accurate
angle displacement platform 4, and the monochromatic neutron beam angle after the monochromator reflection changes 2 Δ θ, for wavelength at any angle
Monochromatic neutron beam all be positioned at the xOz plane;
Give the stepper motor energising of accurate angle displacement platform 4, drive the over-type worm gear in the accurate angle displacement platform 4, make the tilting table face of accurate angle displacement platform 4 along the pivot center CC ' rotation of worm gear, thereby drive pedestal 3, back-up block 2, monochromator 1 around the rotation axis CC ' rotation of accurate angle displacement platform 4.The scrambler that is installed in the worm shaft end in the accurate angle displacement platform 4 is read the corner of worm screw, obtains the anglec of rotation of tilting table face according to 1: 304 reduction gear ratio of worm and wormwheel, angle precision ± 0.0015 °.