Computer Notes

XAS Data Collector:
System crash: Type "xas" to restart in the same window it in which is crashes, look for register dump;
R0= hex, R1 = hex, etc.
Highlighting graphs: Setup, Linestyles

Shift Notes

1. Shut off beam
2. Move the mono to the detune energy
3. Change the temperature
4. Open the hutch
5. Check the oscillator pickup and input voltage
6. Do a vert/horiz scan
7. Detune the mono
8. Change the info in the scan log and write file number in lab book
   
9. Start Scan

NOTE: When you first get on shift, its a good idea to think about what time the beam gets refilled, so that you can plan your scans around that.

1. Kinda self-explanatory

2. Typically its ~50% of the max voltage on I0, but it really depends on the setup: for example if you have mirrors, such as mirrors that cut out the higher harmonics you detune less- using Matt Valdimir's harmonic rejection mirrors we were detuning at 25%. Typical energies are 100-200eV above the edge. For LSMO 6.6keV- which is a little low, but typically we're a little above or below the rule of thumb.

3. Changing the temperature on the temperature controller is just a matter of holding down the "set" button and then clicking the "raise/lower" buttons until you set it to the right energy. The controller does the rest. When making larger temperature jumps, first switch off the toggle that is in-line on the controler cable to the probe. This allows the cryo to heat up, since it takes alot longer than the probe. Wait until it is 15 deg or so away from set temp and then switch the toggle again. Keep an eye on the cryo temp we don't want it getting much less than 5 deg below the set, or more than 10 deg below set temp. If it is rising or falling quickly, increase the flow or decrease the flow accordingly. Make sure that the flow meter is still moving, and that the needle is pointing higher than 1 o'clock.

4. Der

5. 0.2 V/div scale on the oscilliscope means that you want ~300mV on the pickups and ~400mV on one signal and ~800mV on the other signal. To do this, first check the DC level on the scope by switching to DC mode. Second, shut of the horiz. signal generator by unselecting the waveform (DO NOT TURN THE POWER OFF- this ruins the DC offset) and look at channel two (the pickups). Then, turn the horiz. back on and shut off the vert by turning the attenuation all the way up (DO NOT TURN IT OFF). Be sure to check the DC offset of the pickups, making sure its centered, if not adjust the pots on the box.

6. Go to "Motors" and then "Scan Motor" then click on "select devices" then click on "select motor" choose VERT2 or HORIZ2, then click on "select detector" and choose I1. Then change the "start" and "end" to approx. -0.9mm and 0.9mm, finally click on start scan. After scanning, choose the position according to the setup charactistics, and click on "accept position".

7. Go to "Motors" and then "Move Motor" then see #2 for info on this.

8. Change the temperature information. Change the beam current information. Change the sample information. *all of this depends on what's been changed (der). Afterwards, be sure to remember to plot the current scan because you need to see if something catastrophic happens. Go to the plot window, click on "Files" then click on the box labeled "Plot All Sweeps" finally click on button "Plot Std." Finally, click on "Start Scan." Sit back relax and wait for the next one (or work on papers like Bud wants).

A. Extra "der" notes:
1. When you unplug the probe to switch samples (for example) be sure to put the resistor plug in the end of the cable, and SHUT OFF the heater. Select "manual" and turn the heater output to zero.

Setup Notes

1. Unloaded all stuff

2. Get out lab notebook
a. Tape in the checkout list

3. Get stuff ready for Cryostat:
a. There's three temperature controlers- #1 is for probe A: #2 is for the cryostat: #3 is for probe B (be sure to use the right sensor port bc they are calibrated for that specific probe)
b. You need to use the shorted connector on the unused controller port
c. feed the cables through into the hutch
d. inside the hutch plug everything into the cryo- the black mark on the probe is for the
temperature controller- no mark is for the osciallator (if its being used)- the last cable is
plugged into the cryo
e. get power in the hutch
f. get out the aluminum mounting plate to connect the cryostat to the stepper motors
g. put it together with the cryo hanging off the motor UPSTREAM: move the vertical plate connection point where it needs to be so that the cryo's windows are centered in the beam. Make sure that the motor is not at its limit, preferably centered.
h. next, connect the turbo pump to the cryostat- keeping the valve closed, turn on the pump to make sure its working correctly, then open the cryo valve and wait for it to pump down
i. check the detectors- gas is flowing, have enough gas for the run, get them aligned, use the correct gain for each of them (you don't want the detector to read more than 6V and less than 0.1V-usually)

4. Oscillator setup notes:
a. the sample is mounted in the same vertical position as slot 8 (1.86" from mounting holes)
b. the sample is mounted on the probe that was designed for 15 deg alignment, so you need to set it 3 marks off from a 45 deg mark (45-30=15deg)
c. be sure to note the orientation of the oscillator before putting it in the cryo
d. every time you take the probe out, check to make sure the coils haven't moved
e. follow Geza' Kurczveil's Manual on the electronic setup of the oscillator:
-i) in short- pwr, signal generators, oscilascope, connect output signal from box to scope, using DC mode on the scope- adjust the position of zero,
use the DC off-set on the sig. generators to make sure the output isn't clipping, then use the pots on the box to center the sine wave

5. Alignment
a. First do an "eye-ball" check of the vertical and horizontal alignment- do this wrt the windows
b. Secondly, get an idea of what the sample looks like (for powder this isn't an issue)
c. Make sure you start with the slits realatively wide open (~0.7mm vert x ~10mm horiz unfocused powder- THIS IS A RULE OF THUMB) (if you are doing single crystal- start much bigger, maybe 2mm vert x 20 mm horiz)
d. Do vertical and horizontal scans to get an idea of where the sample is located
e. Close the slits down (~0.7mm x ~10mm) if they are bigger
f. Do another scan

Osciallator Calibration

In calculating the sample's angular displacement, we found that we need to measure a trace on the wall of 30" which corresponds to a plus-minus angular displacement of the sample of 2 deg. This means that we have 15" per deg plus-minus on sample.