Set the distances between the slit aperture of the collimator and the axis of rotation as well as between the axis of rotation and the window of the X-ray energy detector both to 5 to 6 cm.Connect the SIGNAL OUT output in the connection panel of the X-ray apparatus to the MCA box by means of the BNC cable.Connect Sensor-CASSY to the computer and connect the MCA box.Feed enough connection cable through to make complete movement of the sensor arm possible.
Connect the signal output of the X-ray energy detector to the BNC socket SIGNAL IN of the X-ray apparatus by means of the BNC cable included.Secure the sensor holder with the mounted X-ray energy detector in the goniometer sensor arm.Guide the connection cable for the table-top power supply through the empty channel of the X-ray apparatus and connect it to the mini-DIN socket of the X-ray energy detector.If necessary exchange the Mo X-ray tube for the Cu x-ray tube (see operating instructions for the X-ray apparatus).The ratio E n/n is constant for every set of lattice planes. The ratio of the radiation energy in the order of diffraction n with the radiation energy in the first order E n/E 1 corresponds to the order of diffraction. It is apparent that with a fixed angle β the lowest energy E 1 occurs in the first order of diffraction. Here E n is the energy of the X-ray radiation reflected in the order of diffraction n. For this case, Bragg's condition can be rewritten with E = hν = hc/λ as follows:Į n/n = hc / 2d sinβ ≈ 620 pm When recording the spectrum by means of an energy resolving detector, not the wavelengths, but the energies are recorded. The angle β applies relative to the lattice planes. With d the distance between the lattice planes and order of diffraction n being an integer number. Incident angle β 1 = diffracted angle β 2 = α If two conditions apply, the waves scattered at the individual atoms will interfere constructively. During this process, the wavelength λ remains unchanged compared to the "incident" wave front. When parallel X-rays strike such a crystal, and assuming that they have wave nature, each lattice-plane component located in a lattice-plane acts as a scattering centre and emits a spherical wave.Īccording to Huygens, the spherical waves superimpose to a "reflected" wave front. Bragg in 1913, the regular arrangement of atoms in a crystal can be interpreted in such a way that they are arranged on parallel lattice planes. Do not block the target arm and the sensor arm of the goniometer and do not use force to move them.Īccording to a model first described by W.H.The goniometer is positioned solely by means of electric stepper motors. When switching the X-ray apparatus on, check whether the ventilator in the tube chamber starts rotating.Protect the X-ray apparatus against access by unauthorized persons.Īvoid overheating of the anode in the X-ray tube.Before putting the X-ray apparatus into operation, inspect it for damage and check whether the voltage is switched off when the sliding doors are opened (See instruction sheet of the X-ray apparatus).The built-in protective and shielding fixtures reduce the dose rate outside the X-ray apparatus to less than 1 µSv/h, which is of the order of magnitude of the natural background radiation. The X-ray apparatus fulfils all regulations on the design of an X-ray apparatus and fully protected device for instructional use and is type approved for school use in Germany (BfS 05/07 V/Sch RöV or NW 807 / 97 Rö). Open topic with navigation Energy dispersive Bragg reflection into different orders of diffractionĬan also be carried out with Mobile-CASSY 2 and Pocket-CASSY Energy dispersive Bragg reflection into different orders of diffraction
0 kommentar(er)
