Instrumentation - making x-rays

1
Instrumentation - making x-rays
'Laboratory' x-ray tubes
anode collects electrons V 0
filament - hot gives off electrons V - approx 40
kV
2
Instrumentation - making x-rays
'Laboratory' x-ray tubes
anode collects electrons V 0
L E K
X
filament - hot gives off electrons V - approx 40
kV
?? hc/E ?(Å) 12.4/kV
3
Instrumentation - making x-rays
'Laboratory' x-ray tubes
anode
focal spot
Filament geometry electron focusing determine
size, shape of focal spot, which influences size,
shape of beam from tube
4
Instrumentation - making x-rays
'Laboratory' x-ray tubes
anode
focal spot
Filament geometry electron focusing determine
size, shape of focal spot, which influences size,
shape of beam from tube For highest intensity,
want smallest size possible, but power limited by
rate of heat transfer in anode
5
Instrumentation - the beam
'Laboratory' x-ray tubes
anode
focal spot
1st problem - tubes usually have liner focal spot
w/ finite width microfocus tubes
6
Instrumentation - the beam
'Laboratory' x-ray tubes
anode
focal spot
1st problem - tubes usually have liner focal spot
w/ finite width microfocus tubes 2nd problem
- x-ray spectrum
intensity
wavelength
7
Instrumentation - the beam
'Laboratory' x-ray tubes
anode
focal spot
1st problem - tubes usually have liner focal spot
w/ finite width microfocus tubes 2nd problem
- x-ray spectrum Need beam conditioning
intensity
wavelength
8
Instrumentation - the beam
'Laboratory' x-ray tubes Pinhole collimator
large intensity loss spectrum
problems remain beam divergence probs
looking at beam
9
Instrumentation - the beam
'Laboratory' x-ray tubes Pinhole collimator
large intensity loss spectrum
problems remain beam divergence
probs Monchromator nearly single WL
beam size probs yet beam divergence
probs
intensity
wavelength
10
Instrumentation - the beam
'Laboratory' x-ray tubes Solns Decrease
focal spot size power limited, but flux still
high spectrum probs remain
11
Instrumentation - the beam
'Laboratory' x-ray tubes Solns Decrease
focal spot size power limited, but flux still
high spectrum probs remain Use new
optics flux high monochromatic
12
Instrumentation - the beam
'Laboratory' x-ray tubes Use new optics flux
high monochromatic
13
Instrumentation - the beam
'Laboratory' x-ray tubes Use new optics flux
high monochromatic 1-D example
14
Instrumentation - the beam
'Laboratory' x-ray tubes Use new optics flux
high monochromatic 2-D
15
Instrumentation - the beam
'Laboratory' x-ray tubes Small focal spot new
2-D optics pinholes distance small
beam low divergence monochromatic
16
Instrumentation - saxs system
'Laboratory' x-ray tubes Small focal spot new
2-D optics pinholes distance small
beam low divergence monochromatic