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Subsections


2. General description of the 6ID-D Beamline

This section gives a general description of the 6ID-D Side Station and its features. In Section 2.2 all motors used at the sidestation are described. In Section 2.5 some general safety precausions are listed.

 


2.1 Beam Conditions

The 6ID-D Side Station is a beamline which uses the white beam of an undulator A insertion device. The optics for both, the 6ID-B Main Station and 6ID-D Side Station are installed in the 6ID-A and 6ID-A extension hutches. First the monochromator of the 6ID-B Main Station, a Kohzu double crystal monochromator with silicon (111) crystals uses the low energy portion of the beam in the range of 3-30 keV. The monochromatic beam of the 6ID-B Main Station is 25 mm higher than the white beam. Directly after the Kohzu monochromator the first monochromator chamber of the 6ID-D Side Station is installed. A white beam mask is used to reduce the beam to a size of 2×4 mm2. Next the low energy x-rays are cut off by different combinations of filters:

  • 1mm C & 1mm Al: for energies above 30 keV
  • 1mm C & 1mm Al & 1mm Cu: for energies above 60 keV
The sidestation uses a Bragg double monochromator in horizontal geometry. The monochromatic beam has a distance of 600 mm from the white beam. As monochromator crystal annealed silicon crystals are used. Three different cuts has been chosen to cover an energy range from 30 keV to 130 keV:
  • Si 111 annealed: 28 - 54 keV
  • Si 311 annealed: 53 - 103 keV
  • Si 331 annealed: 69 - 136 keV
Both beamlines, the 6ID-B Main Station and the 6ID-D Side Station, can operate simultaniously, experiments at the 6ID-B Main Station are carried out at the 6ID-B and 6ID-C hutches, experiments at the 6ID-D Side Station in the 6ID-D hutch. Both beamlines have their own monochromatic beamshutters. If both beamlines are operated at the same time the position of the undulator gap is critical. As is shown in figure 2.1 the intensity of the primary beam at the 6ID-D Side Station decays with wider openings of the undulator gap.

 

Figure 2.1: Scan of the undulator gap. The integral intensity of the monochromatic beam at 92 keV is shown. At this high energies the undulator behaves like an wiggler and nearly no structure is seen for closed gap. If the gap is fairly wide open some structure is seen due to higher harmonics.
396

Even though the distances between the first and second monochromator crystal are quite large the 6ID-D Side Station runs very stable as is shown in figure 2.2.

 

Figure 2.2: Stability of the monochromatic beam at the 6ID-D Side Station. The intensity of time compared to the ring current is shown. Top nearly perfect stability is shown but also in the bottom plot the beamline is quite stable. Regularily performed adjustments (every one to two hours) of the first monochromator (motor momu) or a monochromator stabilizer could easily solv the problem.
\includegraphics[scale=0.6,angle=-90]{general/stability.ps} 404

A drawing and pictures of the sidestation can be found on the webserver of the 6ID-D Side Station.

 


2.2 Motors

This section is intended to give an overview about which motors are available at the sidestation. In table 2.2 all motors are listed with a short description of there purpose. For troubleshooting in table 2.3 the actual motorparameters are listed. If one motor is not working as it is supposed to be compare its parameters to the one in this table.

The motor racks with number 0 and 1 are mounted in the 6ID-A extension. All motor drivers for the optics of the 6ID-D Side Station are mounted in those two racks. Both monochromator crystals including the crystal changers are fully motorised so no access to the 6ID-A or 6ID-A extension hutch should be necessary during operation of the beamline.

The motor drivers of the racks 2 to 6 are mounted inside the 6ID-D hutch. Directly behind the beam entrance is a motorized table (motors xm and ym) with a vertical and horizontal translation. On this table slitsystems 1 and 2 (motors sl1t, sl1b, sl1l, sl1r, sl2t, sl2b, sl2l and sl2r), collimators and a filter bank are mounted to define the incoming beam. For a description of the filter bank see section 2.3.1.

On the fully motorised ψ diffractometer sample environments can be mounted either in an eulerian cradle or on a double tilt. In the setup with a eulerian cradle horizontal and vertical θ motors are available (om_v and om_h) and for the φ and $ \chi$ rotation (chi and phi). In the setup with the double tilt the same motors as with the eulerian cradle are available but the movement of $ \phi$ and $ \chi$ is restricted to ±10 degree. In addition a z translation is mounted below the double tilt and a x and y translation above (motors zs, xs and ys). In addition the whole diffractometer can be moved horizontally and vertically (motors xd and yd). Those motors are very slow and driven by SPD-3M stepping motor drivers. These motor drivers create a lot of electronic noise which is disturbing the detector signal so they are normally switched of once aligned.

On the diffractometer three slit systems are mounted (motors sl3t, sl3b, sl3l, sl3r, sl4t, sl4b, sl4l, sl4r, sl5t, sl5b, sl5l and sl5r). Slit sytstem 3 is mounted in front of the analyser, slit system 4 behind the analyser and slit system 5 in front of the detector.

This $ \psi$ diffractometer was exspecially adapted to the needs of a high energy beamline. The distance between sample and analyser can be as large as 900 mm and between analyser and detector between 300 mm and 600 mm, depending on the setup. This was done by using translations instead of a rotation to simulate the detector arm. This way even heavy detectors, analyser and filter equipment can be mounted. The analyser is also fully motorised and offers 2$ \vartheta$, $ \vartheta$, $ \chi$ and $ \phi$ movements (motors tta, oma, chia and phis). The filters are described in section 2.3.1. To simulate the 2$ \vartheta$ movement of the vertical detectorarm a vertical and horizontal translation (motors tt_v and tt_h)is used on which the analyser rotations are mounted. The horizontal rotation is done in the conventional way (motor tt_h). To give users the possibility to operate this diffractometer as easy as a conventional diffractometer virtual motors (tth and th) have been implemented which simulate the $ \vartheta$ and 2$ \vartheta$ movements, see table 2.1. In case of horizontal geometry those virtual motors are identical to the real motors though tth is driving tt_h plus motor sl3_rot and th is driving om_h. In case of vertical geometry th is driving om_v. But the virtual motor tth is driving the motors tt_h, tt_v, tta, oma and sl3_rot. All the movements have to be calculated with respect to the 2$ \vartheta$ value and the used or not used analyser crystal. This is done automatically by the spec macro hp_motor_6idd.mac. In section 4.11.7 the setup of these macros is described.


Table 2.1: List of the available virtual motors. These motors are simulated by spec programs and are not available under epics.
No name units description
1 tth degree Virtual 2$ \vartheta$ motor difractometer
2 th degree virtual $ \vartheta$ motor diffractometer
3 dummy   dummy motor, nothing is moved



Table 2.2: Table of all motors implemented at the 6ID-D Side Station. First column contains motor number, second the spec motor name, third the epics motor name, fourth the units, fifth and sixth the crate and slot where the driver is placed, seventh the direction in which the home position has to be accessed if implemented and there is a description of the function of the motor in the eighth column.
No spec epics units C S home description
1 monu m1_om degree 0 0 $ \vartheta$ first monochromator crystal
2 m1_chi m1_chi degree 0 1 $ \chi$ first monochromator crystal
3 m1_phi m1_phi degree 0 2 $ \phi$ first monochromator crystal
4 m1_xtal m1_xtal mm 0 3 crystal changer first monochromator
5 m1_y m1_y mm 0 4 vertical movement first monochromator chamber
6 m1_x m1_x mm 0 5 horizontal movement first monochromator chamber
7 filter filter mm 0 6 HomR filter changer for the white beam
9 mond m2_om degree 1 0 $ \vartheta$ second monochromator crystal
10 m2_chi m2_chi degree 1 1 $ \chi$ second monochromator crystal
11 m2_phi m2_phi degree 1 2 $ \phi$ second monochromator crystal
12 m2_xtal m2_xtal mm 1 3 crystal changer second monochromator
13 montrav m1_z mm 1 4 HomF translation of second monochromator chamber
17 xd xd mm 2 0 horizontal movement of the diffractometer
18 yd yd mm 2 1 vertical movement of the diffractometer
19 om_v om_v degree 2 2 HomF vertical $ \vartheta$ diffractometer
20 chi chi degree 2 3 $ \chi$ diffractometer
21 phi phi degree 2 4 HomF $ \phi$ diffractometer
22 om_h om_h degree 2 5 HomF horizontal $ \vartheta$ diffractometer
23 xs xs mm 2 6 horizontal translation below double tilt
24 zs zs mm 2 7 translation in beam direction below double tilt
25 ys ys mm 3 0 vertical translation below double tilt
26 tt_h tt_h degree 3 1 HomF horizontal 2$ \vartheta$ diffractometer
27 tt_y tt_y mm 3 2 vertical movement 2$ \vartheta$ diffractometer
28 tt_z tt_z mm 3 3 horizontal movement 2$ \vartheta$ diffractometer
29 oma oma degree 3 4 HomF $ \vartheta$ analyser
30 chia chia degree 3 5 HomF $ \chi$ analyser
31 phia phia degree 3 6 HomF $ \phi$ analyser
32 tta tta degree 3 7 HomF 2$ \vartheta$ analyser
33 sl1t sl1_t mm 4 0 first slit system in the hutch
34 sl1b sl1_b mm 4 1 first slit system in the hutch
35 sl1l sl1_l mm 4 2 first slit system in the hutch
36 sl1r sl1_r mm 4 3 first slit system in the hutch
37 sl2t sl2_t mm 4 4 slit system in front of the sample
38 sl2b sl2_b mm 4 5 slit system in front of the sample
39 sl2l sl2_l mm 4 6 slit system in front of the sample
40 sl2r sl2_r mm 4 7 slit system in front of the sample
41 xm xm mm 5 0 horizontal movement of yellow table
42 ym ym mm 5 1 vertical movement of yellow table
44 sl3_rot sl3_rot degree 5 3 rotates the slitsystem 3
45 sl3t sl3_t mm 5 4 slit system in front of the analyser
46 sl3b sl3_b mm 5 5 slit system in front of the analyser
47 sl3l sl3_l mm 5 6 slit system in front of the analyser
48 sl3r sl3_r mm 5 7 slit system in front of the analyser
49 sl4t sl4_t mm 6 0 slit system behind the analyser
50 sl4b sl4_b mm 6 1 slit system behind the analyser
51 sl4l sl4_l mm 6 2 slit system behind the analyser
52 sl4r sl4_r mm 6 3 slit system behind the analyser
53 sl5t sl5_t mm 6 4 slit system in front of the detector
54 sl5b sl5_b mm 6 5 slit system in front of the detector
55 sl5l sl5_l mm 6 6 slit system in front of the detector
56 sl5r sl5_r mm 6 7 slit system in front of the detector



Table 2.3: Configuration of all important motor parameters (20th of April 2001). This configuration was done by Norbert Bayer. This table was automatically created by the macro hp_motor_parameter.mac.
No DESC EGU C DIR VELO VBAS ACCL BDST BVEL BACC MRES PREC DHLM DLLM SREV S SBAK SBAS UREV
1 m1_om degrees 0 Pos 1 0.1 0.2 0.01 1 0.2 5e-05 5 7.5 0 2000 10 10 1 0.1
2 m1_chi degrees 0 Pos 4 0.4 0.2 0.1 4 0.2 0.0025 5 3 -5.0125 400 4 4 0.4 1
3 m1_phi degrees 0 Pos 4 0.4 0.2 0.1 4 0.2 0.0025 5 2 -2 400 4 4 0.4 1
4 m1_xtal mm 0 Pos 2 1 0.2 0 2 0.2 0.005 5 199.35 0 400 1 1 0.5 2
5 m1_y mm 0 Pos 0.15625 0.0046875 0.4 0 0.15625 0.4 3.90625e-05 5 8.3 2.3 400 10 10 0.3 0.015625
6 m1_x mm 0 Pos 1.2 0.5 0.5 0 1.2 0.5 0.005 5 5.17 -5.105 400 0.6 0.6 0.25 2
7 filter mm 0 Pos 5 0.5 0.4 0 2.5 0.4 0.000625 5 80 -7 400 20 10 2 0.25
8 motor 8 degrees 0 Pos 1 0.1 0.2 0 0.5 0.2 0.00025 5 100 -100 200 20 10 2 0.05
9 m2_om degrees 1 Pos 1 0.1 0.2 0.01 1 0.2 5e-05 5 8.9961 -0.0039 2000 10 10 1 0.1
10 m2_chi degrees 1 Pos 4 0.4 0.2 0.1 4 0.2 0.0025 5 4 -4 400 4 4 0.4 1
11 m2_phi degrees 1 Pos 4 0.4 0.2 0.1 4 0.2 0.0025 5 4 -4 400 4 4 0.4 1
12 m2_xtal mm 1 Pos 2 1 0.2 0 2 0.2 0.005 5 200 4.81188e-06 400 1 1 0.5 2
13 m2_z mm 1 Pos 25 0.1 0.7 0 25 0.7 0.003125 5 36.67 -3947 400 20 20 0.08 1.25
14 motor 14 degrees 1 Pos 1 0.1 0.2 0 1 0.2 0.00025 5 100 -100 200 20 20 2 0.05
15 motor 15 degrees 1 Pos 1 0.1 0.2 0 1 0.2 0.00025 5 100 -100 200 20 20 2 0.05
16 motor 16 mm 1 Neg 10 1 0.3 0 5 0.4 0.00625 5 90 -100 200 8 4 0.8 1.25
17 xd mm 2 Pos 0.04 0.002 0.3 0 0.02 0.3 5e-05 5 65.8117 -49.2469 400 2 1 0.1 0.02
18 yd mm 2 Pos 0.032 0.00064 0.03 0 0.0064 0.03 1.6e-05 5 66.7275 -100 400 5 1 0.1 0.0064
19 om_v degrees 2 Pos 0.5 0.05 0.5 0 0.5 0.5 0.0001 5 60 -60 1000 5 5 0.5 0.1
20 chi degrees 2 Pos 1.4 0.02 0.4 0 1.4 0.4 0.0002 5 360 -360 1000 7 7 0.1 0.2
21 phi degrees 2 Pos 2 0.02 0.4 0 2 0.4 0.0002 5 100 -100 1000 10 10 0.1 0.2
22 om_h degrees 2 Pos 0.5 0.05 0.5 0 0.5 0.5 0.0001 5 60 -20 1000 5 5 0.5 0.1
23 xs mm 2 Pos 1 0.1 0.2 0 1 0.2 0.000125 5 100 -100 400 20 20 2 0.05
24 zs mm 2 Pos 1 0.1 0.2 0 1 0.2 0.000125 5 100 -100 400 20 20 2 0.05
25 ys mm 3 Pos 1 0.1 0.2 0 1 0.2 0.00025 5 100 -100 200 20 20 2 0.05
26 tt_h degrees 3 Pos 1 0.1 0.3 0 1 0.3 0.00025 5 95 -16 400 10 10 1 0.1
27 tt_y mm 3 Pos 4 0.4 0.4 0 4 0.4 0.00125 5 950 -24.06 400 8 8 0.8 0.5
28 tt_z mm 3 Pos 5 0.5 0.4 0 5 0.4 0.00125 5 950 -30 400 10 10 1 0.5
29 oma degrees 3 Pos 1 0.01 0.4 0.01 1 0.4 0.0001 5 100 -10 1000 10 10 0.1 0.1
30 chia degrees 3 Pos 1 0.1 0.3 0.1 1 0.3 0.0025 5 12 -12 400 1 1 0.1 1
31 phia degrees 3 Pos 1 0.1 0.3 0.1 1 0.3 0.0025 5 13 -13 400 1 1 0.1 1
32 tta degrees 3 Pos 1 0.1 0.3 0.1 1 0.3 0.00025 5 120 -110 400 10 10 1 0.1
33 sl1_t mm 4 Pos 2.5 0.5 0.2 0.1 2.5 0.2 0.00125 5 10 -1 400 5 5 1 0.5
34 sl1_b mm 4 Pos 2.5 0.5 0.2 0.1 2.5 0.2 0.00125 5 10 -1 400 5 5 1 0.5
35 sl1_l mm 4 Pos 2.5 0.5 0.2 0.1 2.5 0.2 0.00125 5 10 -1 400 5 5 1 0.5
36 sl1_r mm 4 Pos 2.5 0.5 0.2 0.1 2.5 0.2 0.00125 5 10 -1 400 5 5 1 0.5
37 sl2_t mm 4 Pos 2.5 0.5 0.2 0.1 2.5 0.2 0.00125 5 10 -1 400 5 5 1 0.5
38 sl2_b mm 4 Pos 2.5 0.5 0.2 0.1 2.5 0.2 0.00125 5 1.20125 -9.79875 400 5 5 1 0.5
39 sl2_l mm 4 Pos 2.5 0.5 0.2 0.1 2.5 0.2 0.00125 5 10 -1 400 5 5 1 0.5
40 sl2_r mm 4 Pos 2.5 0.5 0.2 0.1 2.5 0.2 0.00125 5 1.1875 -9.8125 400 5 5 1 0.5
41 xm mm 5 Pos 2 0.00469 0.4 0.5 2 0.4 0.005 5 41.26 -40 400 1 1 0.002345 2
42 ym mm 5 Pos 0.15625 0.0046875 0.4 0.5 0.15625 0.4 3.90625e-05 5 18 -18 400 10 10 0.3 0.015625
43 motor 43 degrees 5 Pos 1 0.1 0.2 0 1 0.2 0.00025 5 100 -100 200 20 20 2 0.05
44 motor 44 degrees 5 Pos 1 0.1 0.2 0 1 0.2 0.00025 5 100 -100 200 20 20 2 0.05
45 sl3_t mm 5 Pos 5 0.5 0.2 0 5 0.2 0.00125 5 10.1 0 200 20 20 2 0.25
46 sl3_b mm 5 Pos 5 0.5 0.2 0 5 0.2 0.00125 5 10.1 0 200 20 20 2 0.25
47 sl3_l mm 5 Pos 5 0.5 0.2 0 5 0.2 0.00125 5 10.1 0 200 20 20 2 0.25
48 sl3_r mm 5 Pos 2.5 0.5 0.2 0 2.5 0.2 0.00125 5 10.1 0 400 5 5 1 0.5
49 sl4_t mm 6 Pos 5 0.5 0.2 0 5 0.2 0.00125 5 10 -10 200 20 20 2 0.25
50 sl4_b mm 6 Pos 5 0.5 0.2 0 5 0.2 0.00125 5 10 -10 200 20 20 2 0.25
51 sl4_l mm 6 Pos 5 0.5 0.2 0 5 0.2 0.00125 5 10 -10 200 20 20 2 0.25
52 sl4_r mm 6 Pos 5 0.5 0.2 0 5 0.2 0.00125 5 10 -10 200 20 20 2 0.25
53 sl5_t mm 6 Pos 5 0.5 0.2 0 5 0.2 0.00125 5 10 0 200 20 20 2 0.25
54 sl5_b mm 6 Pos 5 0.5 0.2 0 5 0.2 0.00125 5 10 0 200 20 20 2 0.25
55 sl5_l mm 6 Pos 5 0.5 0.2 0 5 0.2 0.00125 5 8.8 -4.2 200 20 20 2 0.25
56 sl5_r mm 6 Pos 5 0.5 0.2 0 5 0.2 0.00125 5 3.5 -3.5 200 20 20 2 0.25


 


2.3 Special equipment

In this section some of the special equipement which was build for the 6ID-D Side Station is described. Due to the fact that some things were still in work when this manual was written not everything in here might work as described or might not be available.

 


2.3.1 Filter banks

There are 2 filter banks with 15 filters each available to reduce the intensities either in front of the sample or in front of the detector. Both filter banks can be loaded with iron or aluminum filters with a thickness of 3 mm each. There are two of the iron and one aluminum filter banks available which can be exchanged very easily within a few minutes. Both filterbanks are controlled by compressed air regulators which are controlled by a 0 to 10 V signal from the digital analog converter (DAC). The DAC can be operated through the macro hp_DAC_vmic4116.mac described in section 4.11.9. The filters are operated by the macro hp_filter_6idd.mac described in section 4.11.10. The macros also provide an automatic absolut calibration for the filters.

 


2.3.2 Detector systems

There are four different detector systems available at the sidestation. Photodiodes are mainly used as monitor systems. They are normally connected to current ampliefiers. The current amplifiers delivers a signal in the range from 0 to 10 volt with is then converted by a volt to frequency converter (VFC) into a frequency with the regular counters can handle.

As a second system two Bicron NaI detectors including amplifiers, single channel analysers and high voltage supplies are available. These detectors are equipped with 10 mm thick crystals in contrast to the standart 1 mm crystal to be able to absorb most of the high energy photons. Warning! This detector can not withstand high countrates and will get damaged if for example hit by the direct not attanuated beam. Make sure that not to much intensity is getting into the detector.

As a third system a Canberra Germanium Detector is available. This system is working together with a digital signal processor (DSP) and a high voltage power supply, both are completely computer controlled through a Canberra AIM. To operated these electronics special MEDM windows are available. The detector can be accessed through spec with the help of the macro package hp_mca.mac which is described in section 4.11.8.

As a fourth system an image plate system is available. This is described in detail in chapter 6.

 


2.4 Sample environments

For the sidestation several sample environments will be available in the near future including a closed cycle with aluminium windows, an Orange liquid helium flow cryostat with aluminium windows, an Orange liquid helium flow cryostat with superconducting coils with magnetic fields up to 5 T and beryllium windows and a furnace.

 


2.5 Saftey

 


next up previous contents index
Next: 3. Getting spec running Up: html Previous: 1. Introduction &nbsp Contents &nbsp Index
Dirk Hupfeld 2001-12-20