Spectrometer
suppressed.
3.2 Hemispherical Analyzer (HSA)
The PHOIBOS Hemispherical Analyzer (HSA) with a mean radius R
0
(100mm/150mm)
measures the energy of charged particles. Charged particles entering the HSA through
the entrance slit S
1
are deflected into elliptical trajectories by the radial electrical field
between the inner hemisphere R
IN
and the outer hemisphere R
OUT
. The radii of the
PHOIBOS hemispheres are 1.25 R
0
and 0.75 R
0
, respectively. The entrance slit S
1
and exit
plane S
2
, are centered on the mean radius R
0
:
R
0
=
R
inner
R
out
2
=
150mm
(2)
For a fixed electrical field gradient, only particles with kinetic energies in a certain en-
ergy interval are able to pass through the full deflection angle from the entrance slit S
1
to the exit plane S
2
. Particles with higher kinetic energy approach the outer hemi-
sphere, whereas particles with lower kinetic energy are deflected toward the inner
hemisphere. Those particles, which enter the HSA normal to S
1
and move through the
hemispheres on the central circular trajectory, have the nominal pass energy E
pass
:
E
pass
=−
q
k
∇
V
(3)
where q is the charge of the particle,
∆
V is the potential difference V
out
- V
in
applied to
the hemispheres, k is the calibration constant,
k
=
R
inner
R
out
2R
0
R
out
−
R
inner
=
0.9375
(4)
These particles reach S
2
at the nominal radial position R
0
. If the HSA accepts the half
angle
α
in the dispersion direction, the HSA resolution or FWHM (full width at half max-
imum) of the transmitted line
∆
E
an
is given by
E
an
E
pass
=
S
2
R
0
2
4
(5)
where S=(S
1
+ S
2
)/2. This value is a constant of the analyzer.
There are additional contributions to the line width observed in the spectrum. For
photo-emission lines, the main additional contributions are:
●
inherent line width of the atomic level
∆
E
level
(e.g. O 1s, C 1s),
18
Summary of Contents for PHOIBOS 100
Page 1: ...PHOIBOS Hemispherical Energy Analyzer Series PHOIBOS 100 PHOIBOS 150 3 1...
Page 6: ...Table of Contents PHOIBOS...
Page 10: ...Introduction 4 PHOIBOS...
Page 13: ...Electrical Connections Figure 2 Connection Scheme PHOIBOS 7...
Page 14: ...Components and Connections Figure 3 Analyzer Housing PHOIBOS100 8 PHOIBOS...
Page 15: ...Electrical Connections Figure 4 Analyzer Housing PHOIBOS150 PHOIBOS 9...
Page 42: ......
Page 51: ...SpecsLab Hardware and Software Installation PHOIBOS 45...
Page 52: ......
Page 62: ......
Page 78: ...Analyzer Checks Figure 33 Schematics of the 12 pin Analyzer Feedthrough 72 PHOIBOS...
Page 80: ......
Page 86: ......
Page 92: ...List of Figures Figure 39 Alignment Pin 84 II PHOIBOS...
Page 93: ...List of Figures PHOIBOS III...
Page 94: ......
Page 96: ......
Page 98: ...Index PHOIBOS...
