Manual_XRaySource

Mg and Al K alpha X-Ray Source

Twin anode Mg-Al XR3 X-RAY SOURCE (Thermo Fisher scientific). 

Be careful when the X-ray source is inside and you need to rotate or move the sample because they are very close to each other!
PRECAUTIONS: All windows should be completely covered with lead glasses or lead screens before operating the source. 
UPDATED PROCEDURE 2024

SAMPLE AND X-RAY POSITIONING

-SCREENS 14,15,16 and 22 have to be positioned.
-Before sample transfer or movement make sure that the x ray source is fully retracted
-Typical position: x=25,y=28,z=9-11 theta=240. Change the angle from 180 to 240 when z is 17.
NOTE: if one needs a different x/y position, in order to have the same distance from the analyser use this formula: Deltax=+0.5-->Deltay=-0.86
Eg: x=25.5, y=27.1
-Move the linear transfer of teh x-ray source inside until it is 8 mm from the fully inside position. We use a 7 wrench with the handle of 8mm lateral size as 'endswitch'
-From the LEED window and the top window check that the x-ray source is far enough from the sample cryostat.


Dimension completely retracted. From the flange to the ending part of the source=22.5 cm
Linear transfer: it can be moved by 7.5 cm
Distance from the CF38 flange of the chamber to the center of the chamber (sample)=30 cm (sample at 20, 20)
Working distance of the X-Ray source from 1 to 2 cm from the sample
This means that the linear tranfer has to be moved by 5.5 cm
 

DEGASSING PROCEDURE: Please read Manual pag 34

1) Open water flux IN and OUT (pressure between 4 and 5.7 bar)
2) Switch on the powersupply 
3) Run THERMO ADVANTAGE software (Login in PBACH5 as Vgengineer and close Advantage in other accounts if opened there)

4) Select Insert x-ray mode-->Select gun: twin anode x-ray gun; Select power: Mg 300W BACH
Menu Instrument select: X-Ray Gun Control:

gun: twin anode x-ray gun; Power: Degas
Press Details...XR4Gun Diagnosis will appear
Starting Conditions:
HT Voltage=0
Fil cure limit=0
Power 0
beam current 0 mA
fil cure limit 0

3) Water Cooling: 4.2 BARS
4) Switch on the power supply
5) Set beam current 4.5 mA and click APPLY

OPERATING X RAY SOURCE

UPDATED PROCEDURE 2024
- Open water OUT and IN 4-5 bar (top tubes). Check that the red LED is off above 3 bar.
-Turn on the electronics at least 10 mintes before starting for stabilization
- PBACH8 and run THERMO ADVANTAGE software (close Advantage in other accounts if opened there)
--->Instrument--->check Device is OK-(*)->Select Gun: Twin-Anode X-Ray Gun
--->Select power: Mg 15W BACH and press Apply (MONITOR THE pressure in the main. It will increase to 10-8 and quickly decrease to low 10-9)
Step by step, monitoring the pressure Select increasing power: Mg 100W,200W,300W and press Apply. P should be lower than 5x10-9 mbar.
(*) this checks that the interlocks are fine. If one is red, but it is ok, press reset.
After about 2 minutes the flux (and pressure) should be stable (typically 2.5x10-9 mbar) and ready to measure.
To shutdown, press Shutdown. Then wait for 10 min and close water flux. Retract the x-ray source.
The same procedure is for AlKa
AlKalpha (Fermi edge at PE100: 1481.72eV, FWHM=1 eV)
MgKalpha (Fermi edge at PE100: 1248.67, FWHM=0.86 eV)

--------
OLD PROCEDURE (2014)
1) Login in PBACH5 as Vgengineer and run THERMO ADVANTAGE software (close Advantage in other accounts if opened there)
2) Select Insert x-ray mode-->Select gun: twin anode x-ray gun; Select power: Mg 300W BACH

3)Menu Instrument select: X-Ray Gun Control:
gun: twin anode x-ray gun; Power: Mg 300W BACH
Press Details...XR4Gun Diagnosis will appear
Starting Conditions:
Set all values to zero and press APPLY: HT Voltage=0, Fil cure limit=0, Power 0
beam current SET: 5 mA  and click APPLY
fil cure limit SET 0.5 A, 1 A, 1.5 A, …4.2A (Mg has been degassed up to 4.8 A but not necessary to reach 4.8 A during normal operation)

Then:

HT Voltage: (steps 0.1 kV when you degas) 1KV, 3kV, …15kV
At the end: Set Beamcurrent 20 mA

SWITCHING OFF X-RAY GUN:

To switch off go down with the same procedure (exactly opposite direction, last action will be close water flux)
In the software, when everything is zero press Turn OFF in XR4 Gun Diagnostics and Shut Down in the panel X-Ray Gun Control.