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Monochromated X-Ray Source with XR5 Electron Gun
Interlock
Interlocked
Inhibit
Name
Tripped By
s
XR3/XR4 Twin X-
Power to
TWIN cover
Ray source
source.
protective cover
being removed.
MONO cover
XR5 Mono Covers
Power to
Source Protective
source.
cover being
removed.
VACUUM
Main chamber (ion
Power to
gauge) pressure
source.
above
-6
1x10
mbar
WATER flow
Water flow through
Power to
the X-Ray source
source.
(XR4 or MXR1)
drops below 2.8
l/min
CABLES
Cables removed
Power to
from rear of
source.
T352/NT power
supply
Table 1: T352 Instrument Interlocks
There are additional safety features built into the T352/NT power supply that will inhibit
power to the X-ray source but will display as a "pop-up" box by the Avantage software,
they include:-
Temperature in T352 Power Supply rises to unacceptable levels.
Current drawn from T352 Power Supply HV greater than 60 mA.
Drain from HV through X-ray water lines greater than 20 mA.
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7
Status Displayed to Operator
Interlock display in software will display FAIL in
RED
In addition light "1" LED on the rear of the power
supply will illuminate RED.
Interlock display in software will display FAIL in
RED
In addition light "2" LED on the rear of the power
supply will illuminate RED.
Interlock display in software will display FAIL in
RED
In addition light "3" LED on the rear of the power
supply will illuminate RED.
Relay A on Ion Gauge Controller (IGC) LCD
display:
LED On = Enabled
LED Off = Tripped
Interlock display in software will display FAIL in
RED
In addition light "4" LED on the rear of the power
supply will illuminate RED.
Interlock display in software will display FAIL in
RED
In addition light "5" LED on the rear of the power
supply will illuminate RED.
Monochromator and XR5 (HA600054)
Monochromated X-Ray Source with XR5 Electron Gun
3
Description
3.1
Introduction
The Monochromated X-Ray Source produces X-Rays which have well defined energy
resolution and are micro-focussed onto the sample to give a spatially defined area of
analysis. To achieve this several distinct components are employed. Firstly there is an
electron gun, the XR5, designed to provide a high power source of focused electrons
at energies of up to 15kV. These electrons impact on the anode, in this case an
aluminium coated version, to produce X-Rays at an energy of around 1486.6eV.
The X-Rays are then diffracted by a pair of quartz crystals which are arranged such
that the angle between the crystal lattice and the X-Rays is the appropriate Bragg
angle. The diffracted X-Rays are thus monochromated to give a pure Al K beam (of
much lower energy spread). The crystals are also shaped and positioned so that the
diffracted X-Rays are focussed into a well defined spot on the sample surface at the
analysis position.
The XR5 electron gun and anode voltage are controlled by a single power supply, the
T352/NT. This supply has no manual user interfaces, being controlled entirely from the
Avantage Datasystem.
The ESCALAB 250 monochromator system consists of 5 major components:
XR5 Electrostatic Electron Gun
Monochromator Water System
T352/NT Digital X-ray Supply
Monochromator Crystal Assembly
Data System Monochromator Control Software.
Figure 3-1: The Monochromator Assembly
Monochromator and XR5 (HA600054)
8
Issue 5
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