Ken Andersen. H1 H5 Extract Brightness from Neutron Measurement Needs end-of-guide position with...
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Transcript of Ken Andersen. H1 H5 Extract Brightness from Neutron Measurement Needs end-of-guide position with...
1011
1012
1013
0 2 4 6 8 10 12
ILL Cold Source Brightnesses
HCS brightness (Ageron measured)
HCS brightness (Calzavara)
VCS Brightness (Ageron calculated)
VCS brightness (Calzavara)
Wavelength (Å)
H1
H5
Extract Brightness from Neutron Measurement Needs end-of-guide position with chopper and
TOF analysisReadily available on H1: Figaro, D17, PF1BNot so readily available on H5 (IN15?)
Propagate backwardsCorrect for attenuation through window
materials etc.Scale using Au-foil measurement
Detector spectrum corrected for chopper opening time
0
5000
1 104
1.5 104
2 104
2.5 104
0
1 106
2 106
3 106
4 106
5 106
0 2 4 6 8 10 12 14
Figaro spectrum
measured
measured*T/ t
lambda (A) time
dis
tan
ce
Δt Δt
Al Bragg edges measured on D17
0
0.2
0.4
0.6
0.8
1
0 5 10 15 20
Transmission of AG3 Aluminium on D17
75mm AG3 Al
50mm AG3 Al
wavelength (Å)
0.5
0.6
0.7
0.8
0.9
1
0 10 20 30 40 50 60 70 80
AG3 Aluminium Transmission on D17
Thickness of AG3 window (mm)
y = exp(-m1*x)
ErrorValue
8.2921e-50.0067182m1
NA4.5788e-5Chisq
NA0.99973R
0.5
0.6
0.7
0.8
0.9
1
0 10 20 30 40 50 60 70 80
AG3 Aluminium Transmission on D17
Thickness of AG3 window (mm)
y = exp(-m1*x)
ErrorValue
8.2921e-50.0067182m1
NA4.5788e-5Chisq
NA0.99973R
Al window transmission
2 106
2.5 106
3 106
3.5 106
4 106
4.5 106
5 106
2 2.5 3 3.5 4 4.5 5 5.5 6
Figaro spectrum
lambda (A)
T=0.875
⇒t=20mm
Al window transmission
0
0.2
0.4
0.6
0.8
1
0 5 10 15 20
Transmission of Al as a function of neutron wavelength
T(75mmAl)T(50mmAl)T(20mmAl) from 75mm dataT(20mmAl) from 50mm data
lambda
0
1 106
2 106
3 106
4 106
5 106
6 106
7 106
0 5 10 15
Figaro spectrum
figspec*T/DTfigspec*(T/DT)/Altrans
lambda (A)
Detector efficiency
lnePP )(0 1
82.0)Å8.1(
b5.4
30
Pp
mml Window thickness = 10mm- half of the total 20mm
Attenuation through frame-overlap mirror
0.01
0.1
1
0.1 1 10
Inverse attenuation length of single-crystal Si at 300K
measured (Freund)
absorption
used for Figaro data
(Å)
0.7mm Si at 3° angle
Final corrected spectrum
0
1 106
2 106
3 106
4 106
5 106
6 106
7 106
0 5 10 15
Figaro spectrum
figspec*T/DTfigspec*(T/DT)/Altransfigspec*(T/DT)/Altrans/deteff/airtrans/Sitrans
lambda (A)
Flux (
arb
. u
nit
s)
Propagate backwards through guide
0.0001
0.001
0.01
0.1
0 5 10 15 20
Guide transmission
H171 guideFigaro with 5mm slits
wavelength (Å)
1000
104
105
106
107
108
109
106
107
108
109
1010
1011
1012
0 5 10 15 20
Figaro flux
source brightness
wavelength (Å)
outinguide AAT BrightnessFlux
Gold foil measurementAugust 2007after installation of H17
guidesat VS position: entrance
into level C casemateH171 (Figaro)
Φcapt=1.07×1010 n/cm2/sH172 (Granit)
Φcapt=1.57×1010 n/cm2/s
Evaluate capture flux at VS and rescale
dTAA guideoutin Å8.1
BrightnessFlux Capture
109
1010
1011
1012
1013
1014
1 10
Cold Source Brightness
Figaro brightnessAgeron brightness
wavelength (Å)
Comparison of capture fluxes
Capture Flux(n/cm2/s)
Measured Calculated from Ageron
Present calculation
H171 (Figaro) VS 4.24×1010
August 20072.88×1010 (4.24×1010)
H172 (Granit) VS 6.19×1010
August 20074.03×1010 5.98×1010
H172 (Granit) mono 4.4-4.8×1010
April 20083.20×1010 4.63×1010
Spectral flux at Granit monochromator
100
1000
104
105
106
107
108
109
1010
1 10 100
Flux at H172 Granit monochromator
Ageron
from Figaro spectrum
wavelength (Å)
Spectral flux at λ=8.9Å (n/cm2/s/Å)
Previous estimate
(2005-2007)6.4×108
Ageron brightness 4.4×108
Present calculation 5.4×108
Brightnesses of HCS & VCS
1011
1012
1013
0 2 4 6 8 10 12
ILL Cold Source Brightnesses
HCS brightness (Ageron measured)HCS brightness (Calzavara)VCS Brightness (Ageron calculated)VCS brightness (Calzavara)VCS brightness (Figaro)
Wavelength (Å)