LEYBOLD Physics Leaflets P7.1.2.1 By moving the sensor holder(b),set the distance s2 be- In coupled scanning mode,move the target back by 10.2 tween the target arm and the slit diaphragm of the sensor (even if this takes you into the negative range!). seat to approx.6 cm. Save the positions of the target and the sensor as the "zero Mount the target holder(f)with target stage. position of the measuring system"by pressing TARGET, Manually align the target and sensor arm horizontally using COUPLED and B LIMITS simultaneously. the ADJUST knob and save these positions as the"zero position of the measuring system"by pressing TARGET, Recording the diffraction spectrum: COUPLED and B Limits at the same time(see Instruction Sheet for x-ray apparatus). Start the software "X-ray Apparatus",check to make sure that the apparatus is connected correctly,and clear any existing measurement data using the button or the F4 Preparing the PC-based measurement: key Connect the RS-232 output and the serial interface on your Set the measuring time per angular step At =10s and the PC (usually COM1 or COM2)using the 9-pin V.24 cable angular step width△β=0.1°. (supplied with x-ray apparatus). Press the COUPLED key to activate 2 coupling of target If necessary,install the software"X-ray Apparatus"under and sensor and set the lower limit of the target angle to 4 Windows 9x/NT(see Instruction Sheet for x-ray apparatus) and the upper limit to 34. and select the desired language. Start measurement and data transfer to the PC by pressing the SCAN key. When you have finished measuring,save the measure- ment series under an appropriate name by pressing the button里or the F2key. a)Bragg reflection at an NaCl monocrystal: Press the ZERO key to return the target and sensor to the Carrying out the experiment current zero position. Notes: Remove the LiF crystal and carefully mount the NaCI crystal in its place. NaCl and LiF crystals are hygroscopic and extremely fragile. Store the crystals in a dry place;avoid mechanical stresses on Determining the zero position of the measuring system the crystals;handle the crystals by the short faces only. In coupled scanning mode,set the target to about 7.2 If the counting rate is too low,you can reduce the distance sa using the ADJUST knob. between the target and the sensor somewhat.However,the Switch on the tube high voltage with HV on/off. distance should not be too small,as otherwise the angular Leave the target position unchanged and,in sensor scan- resolution of the goniometer is no longer sufficient to separate ning mode,manually find the counting rate maximum for the characteristic K and Ke lines. the first reflection maximum of the Ka line. Leave the sensor unchanged in the maximum counting rate position and manually find the maximum of the count- a)Bragg reflection at an LiF monocrystal: ing rate in target mode. Switch between sensor and target modes and check Loosen knurled screw(g),place the LiF crystal flat on the whether you have found the counting rate maximum. target stage,carefully raise the target stage with crystal all In coupled scanning mode,move the target back by 7.2 the way to the stop and gently tighten the knurled screw (even if this takes you into the negative range!). (prevent skewing of the crystal by applying a slight pres- sure). Save the positions of the target and the sensor as the"zero Set the tube high voltage U=35.0 kV and the emission position of the measuring system"by pressing TARGET, COUPLED and B LIMITS simultaneously. current I 1.00 mA. Recording the diffraction spectrum: Determining the zero position of the measuring system In coupled scanning mode,set the target to about 10.2 Start the software "X-ray Apparatus"or clear any existing using the ADJUST knob. measurement data using the button or theF4 key. Switch on the tube high voltage with HV on/off. Press the COUPLED key to activate 20 coupling of target Leave the target position unchanged and,in sensor scan- and sensor and set the lower limit of the target angle to 4 ning mode,manually find the counting rate maximum for and the upper limit to 24. the first reflection maximum of the Ka line. Start measurement and data transfer to the PC by pressing Leave the sensor unchanged in the maximum counting- the SCAN key. rate position and manually find the maximum of the count- ing rate in target mode. When you have finished measuring,save the measure- Switch between sensor and target modes and check ment series under an appropriate name by pressing the whether you have found the counting rate maximum. button or the F2 key. 3– By moving the sensor holder (b), set the distance s2 be￾tween the target arm and the slit diaphragm of the sensor seat to approx. 6 cm. – Mount the target holder (f) with target stage. – Manually align the target and sensor arm horizontally using the ADJUST knob and save these positions as the “zero position of the measuring system” by pressing TARGET, COUPLED and b Limits at the same time (see Instruction Sheet for x-ray apparatus). Preparing the PC-based measurement: – Connect the RS−232 output and the serial interface on your PC (usually COM1 or COM2) using the 9-pin V.24 cable (supplied with x-ray apparatus). – If necessary, install the software “X-ray Apparatus” under Windows 9x/NT (see Instruction Sheet for x-ray apparatus) and select the desired language. Carrying out the experiment Notes: NaCl and LiF crystals are hygroscopic and extremely fragile. Store the crystals in a dry place; avoid mechanical stresses on the crystals; handle the crystals by the short faces only. If the counting rate is too low, you can reduce the distance s2 between the target and the sensor somewhat. However, the distance should not be too small, as otherwise the angular resolution of the goniometer is no longer sufficient to separate the characteristic Ka and Kb lines. a) Bragg reflection at an LiF monocrystal: – Loosen knurled screw (g), place the LiF crystal flat on the target stage, carefully raise the target stage with crystal all the way to the stop and gently tighten the knurled screw (prevent skewing of the crystal by applying a slight pres￾sure). – Set the tube high voltage U = 35.0 kV and the emission current I = 1.00 mA. Determining the zero position of the measuring system – In coupled scanning mode, set the target to about 10.28 using the ADJUST knob. – Switch on the tube high voltage with HV on/off. – Leave the target position unchanged and, in sensor scan￾ning mode, manually find the counting rate maximum for the first reflection maximum of the Ka line. – Leave the sensor unchanged in the maximum counting￾rate position and manually find the maximum of the count￾ing rate in target mode. – Switch between sensor and target modes and check whether you have found the counting rate maximum. – In coupled scanning mode, move the target back by 10.28 (even if this takes you into the negative range!). – Save the positions of the target and the sensor as the “zero position of the measuring system” by pressing TARGET, COUPLED and b LIMITS simultaneously. Recording the diffraction spectrum: – Start the software “X-ray Apparatus”, check to make sure that the apparatus is connected correctly, and clear any existing measurement data using the button or the F4 key. – Set the measuring time per angular step Dt = 10 s and the angular step width Db = 0.18. – Press the COUPLED key to activate 2q coupling of target and sensor and set the lower limit of the target angle to 48 and the upper limit to 348. – Start measurement and data transfer to the PC by pressing the SCAN key. – When you have finished measuring, save the measure￾ment series under an appropriate name by pressing the button or the F2 key. a) Bragg reflection at an NaCl monocrystal: – Press the ZERO key to return the target and sensor to the current zero position. – Remove the LiF crystal and carefully mount the NaCl crystal in its place. Determining the zero position of the measuring system – In coupled scanning mode, set the target to about 7.28 using the ADJUST knob. – Switch on the tube high voltage with HV on/off. – Leave the target position unchanged and, in sensor scan￾ning mode, manually find the counting rate maximum for the first reflection maximum of the Ka line. – Leave the sensor unchanged in the maximum counting￾rate position and manually find the maximum of the count￾ing rate in target mode. – Switch between sensor and target modes and check whether you have found the counting rate maximum. – In coupled scanning mode, move the target back by 7.28 (even if this takes you into the negative range!). – Save the positions of the target and the sensor as the “zero position of the measuring system” by pressing TARGET, COUPLED and b LIMITS simultaneously. Recording the diffraction spectrum: – Start the software “X-ray Apparatus” or clear any existing measurement data using the button or the F4 key. – Press the COUPLED key to activate 2q coupling of target and sensor and set the lower limit of the target angle to 48 and the upper limit to 248. – Start measurement and data transfer to the PC by pressing the SCAN key. – When you have finished measuring, save the measure￾ment series under an appropriate name by pressing the button or the F2 key. LEYBOLD Physics Leaflets P7.1.2.1 3