Electron Spectroscopy at JYFLnpg.dl.ac.uk/GREAT/sagelisatalks/Paul_Greenlees_sage.pdf · BGO...
Transcript of Electron Spectroscopy at JYFLnpg.dl.ac.uk/GREAT/sagelisatalks/Paul_Greenlees_sage.pdf · BGO...
Introduction Magnetic Field Simulations Efficiency Tests Stray Field Vs. BGO WDWGFH?
Electron Spectroscopy at JYFL
PTG, Juha Sorri, et al.,
Department of PhysicsUniversity of Jyväskylä
Daresbury2.9.2005
PTG, JS, et al., (JYFL, Finland) Electron Specroscopy at JYFL Daresbury 2.9.2005 1 / 20
Introduction Magnetic Field Simulations Efficiency Tests Stray Field Vs. BGO WDWGFH?
TheSACREDElectron Spectrometer
Beam In
Cold Finger
25 Element
DetectorAnnular Si
High Voltage Barrier
Carbon He Containment Windows
Target Chamber
RITUTo
H. Kankaanpää et al., NIM A534, 503 (2004)P. A. Butler et al., NIM A381, 433 (1996)
PTG, JS, et al., (JYFL, Finland) Electron Specroscopy at JYFL Daresbury 2.9.2005 2 / 20
Introduction Magnetic Field Simulations Efficiency Tests Stray Field Vs. BGO WDWGFH?
Field Profile - 560A
0 10 20 30 40 50 60 70-0,10
-0,05
0,00
0,05
0,10
0,15
0,20
0,25
0,30
0,35
0,40
0,45
0,50
B
[T]
X [cm]
Tangential field (10mm) Normal (radial) field (10mm) Tangential field (30mm) Normal (radial) field (30mm)
Bmax
/Bmin
=1.34
PTG, JS, et al., (JYFL, Finland) Electron Specroscopy at JYFL Daresbury 2.9.2005 3 / 20
Introduction Magnetic Field Simulations Efficiency Tests Stray Field Vs. BGO WDWGFH?
TheJUROGAM Germanium Array
43 Phase I and GASP-type Ge detectors -EUROBALL and U.K.-France loan pool
Total Photopeak Efficiency 4.2% @ 1.3 MeV
Software Compton suppression
Autofill system built by University of York,part of GREAT
Target chamber built by IReS Strasbourg,allows use of rotating target wheel
Modified EUROGAM support structure
PTG, JS, et al., (JYFL, Finland) Electron Specroscopy at JYFL Daresbury 2.9.2005 4 / 20
Introduction Magnetic Field Simulations Efficiency Tests Stray Field Vs. BGO WDWGFH?
RDT with SACRED
0
5
10
15
50 100 150 200 250
Energy (keV)
0
100
200
300
400
500
600
2+−
0+ L
2+−
0+ M
4+−
2+ L
4+−
2+ M
8+−
6+ K
6+−
4+ L
Electron Singles
1 Pixel of Detector
226U α−tagged electrons
Counts
1x106
2x106
3x106
(6+−
4+ K
)
226U simulated spectrum
H. Kankaanpää et al.,NIM A534, 503 (2004)see also:R.D. Humphreys et al.,PRC69, 064324 (2004)
PTG, JS, et al., (JYFL, Finland) Electron Specroscopy at JYFL Daresbury 2.9.2005 5 / 20
Introduction Magnetic Field Simulations Efficiency Tests Stray Field Vs. BGO WDWGFH?
Conversion Electron Spectroscopy of254No
P.A. Butler et al., PRL89, 202501 (2002)
R.D. Humphreys et al., PRC69, 064324 (2004)
PTG, JS, et al., (JYFL, Finland) Electron Specroscopy at JYFL Daresbury 2.9.2005 6 / 20
Introduction Magnetic Field Simulations Efficiency Tests Stray Field Vs. BGO WDWGFH?
Permanent Magnets
~15cm ~30cm
IronNdFeB 40 MGOe
40mm
100mm
PTG, JS, et al., (JYFL, Finland) Electron Specroscopy at JYFL Daresbury 2.9.2005 7 / 20
Introduction Magnetic Field Simulations Efficiency Tests Stray Field Vs. BGO WDWGFH?
Permanent Magnets
Permanent Magnet Solenoid
|B|, Tesla
Length, cm
0.2
0.15
0.1
0.05
0
0 1 2 3 4 5 6 7 8 9
|B|, Tesla
Length, cm
0.4
0.3
0.2
0.1
0
0 1 2 3 4 5 6 7 8 9
|B|, Tesla
Length, cm
0.4
0.3
0.2
0.1
0
0 5 10
|B|, Tesla
Length, cm
0.3
0.25
0.2
0.15
0.1
0.05
0
0 5 10 15 20
1 3
9 27
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Introduction Magnetic Field Simulations Efficiency Tests Stray Field Vs. BGO WDWGFH?
Electromagnets - Possible Geometry?
PTG, JS, et al., (JYFL, Finland) Electron Specroscopy at JYFL Daresbury 2.9.2005 9 / 20
Introduction Magnetic Field Simulations Efficiency Tests Stray Field Vs. BGO WDWGFH?
Electromagnets - Possible Geometry?
PTG, JS, et al., (JYFL, Finland) Electron Specroscopy at JYFL Daresbury 2.9.2005 10 / 20
Introduction Magnetic Field Simulations Efficiency Tests Stray Field Vs. BGO WDWGFH?
Electromagnets - Possible Geometry?
RITU
JUROGAM
SACRED
PTG, JS, et al., (JYFL, Finland) Electron Specroscopy at JYFL Daresbury 2.9.2005 11 / 20
Introduction Magnetic Field Simulations Efficiency Tests Stray Field Vs. BGO WDWGFH?
Field Profile 560A
560A |B|, Tesla
Length, cm
0.5
0.4
0.3
0.2
0.1
00 10 20 30 40 50 60 70
PTG, JS, et al., (JYFL, Finland) Electron Specroscopy at JYFL Daresbury 2.9.2005 12 / 20
Introduction Magnetic Field Simulations Efficiency Tests Stray Field Vs. BGO WDWGFH?
Field Profile 560A
PTG, JS, et al., (JYFL, Finland) Electron Specroscopy at JYFL Daresbury 2.9.2005 13 / 20
Introduction Magnetic Field Simulations Efficiency Tests Stray Field Vs. BGO WDWGFH?
Attempt to Simulate Pocket in Field
0 10 20 30 40 50 60 70-0,05
0,00
0,05
0,10
0,15
0,20
0,25
0,30
0,35
0,40
0,45
0,50
0,55
0,60
Bmax
/Bmin=1.48
B [T
]
X [cm]
Tangential field (10mm) Normal field (10mm) Tangential field (30mm) Normal field (30mm) Measured values (Bt, r=10mm)
0 10 20 30 40 50 60 70
-0,050,000,050,100,150,200,250,300,350,400,450,500,550,600,650,70
Bmax
/Bmin=1.73
B [T
]
X [cm]
Tangential field (10mm) Normal field (10mm) Tangential field (30mm) Normal field (30mm) Measured (Bt, r=10)
0 10 20 30 40 50 60 70
-0,050,000,050,100,150,200,250,300,350,400,450,500,550,600,650,70
Bmax
/Bmin=2.06
B [T
]
X [cm]
Tangential field (10mm) Normal field (10mm) Tangential field (30mm) Normal field (30mm) Measured (Bt,r=10mm)
0 10 20 30 40 50 60 70-0,05
0,00
0,05
0,10
0,15
0,20
0,25
0,30
0,35
0,40
0,45
0,50
0,55
0,60
Bmax
/Bmin=3.4
B [T
]
X [cm]
Tangential (10mm) Normal (10mm) Tangential (30mm) Normal (30mm) Measured points
PTG, JS, et al., (JYFL, Finland) Electron Specroscopy at JYFL Daresbury 2.9.2005 14 / 20
Introduction Magnetic Field Simulations Efficiency Tests Stray Field Vs. BGO WDWGFH?
Attempt to Simulate Pocket in Field
0,0
0,5
1,0
1,5
2,0
2,5
3,0
3,5
4,0
(12:5) 3 coils (26)(17:0)(15:2.5)Original (8.5:8.5)
Magnetic max-min ratio Efficiency (compared to orig. design)
Electron: 45 keV@channel 102
0
1
2
3
4
Magnetic Max-Min ratio Efficiency (compared to orig. design)
Electron: 320 keV@channel 352
(12:5) 3 coils (26)(17:0)(15:2.5)Original (8.5:8.5)
PTG, JS, et al., (JYFL, Finland) Electron Specroscopy at JYFL Daresbury 2.9.2005 15 / 20
Introduction Magnetic Field Simulations Efficiency Tests Stray Field Vs. BGO WDWGFH?
Effect of Stray Field on Photomultplier Output
A
BC
D
E
F
GH
I
JTube labels
Angle=0
Angle=90
Angle=45
Distance between SACREDcenter line and
Tube A=20cmTube C=25cm
Distance between SACREDcenter line and
Tube A=40cm
Tube A offset from BGO centerline 5cmTube C is on BGO center line
Tube C=40cm
(SFC34)
Distance between SACREDcenter line and
Tube A=30cmTube C=34cm
PTG, JS, et al., (JYFL, Finland) Electron Specroscopy at JYFL Daresbury 2.9.2005 16 / 20
Introduction Magnetic Field Simulations Efficiency Tests Stray Field Vs. BGO WDWGFH?
Effect of Stray Field on Photomultplier Output
0,5 1,0 1,5 2,0 2,5 3,0 3,5 4,00
100
200
300
400
500
600
Signal
[mV
]
B [mT]
HV adjusted togive 1mV/keV,137Cs source
PTG, JS, et al., (JYFL, Finland) Electron Specroscopy at JYFL Daresbury 2.9.2005 17 / 20
Introduction Magnetic Field Simulations Efficiency Tests Stray Field Vs. BGO WDWGFH?
Effect of Stray Field on Photomultplier Output
0 1000 2000 30000
1000
2000
3000
4000
5000
6000
7000
HV=1600
C
ount
s
Channel
HV=1500
Reference
PTG, JS, et al., (JYFL, Finland) Electron Specroscopy at JYFL Daresbury 2.9.2005 18 / 20
Introduction Magnetic Field Simulations Efficiency Tests Stray Field Vs. BGO WDWGFH?
Effect of Stray Field on Photomultplier Output
1 2 3 4 5 60,1
1
10
100
1000
10000
1=ref 2=no shield 3=1cm shield 4=2cm shield 5=2cm+dyn.shield 6=3cm+dyn.shield
N/A
P/V Centroid [channel] FWHM [channel] signal [mV]
N/A
Tube A angle=0
1 2 3 4 5
10
100
1000
10000
1=ref 2=no shield 3=1cm shield 4=2cm shield 5=2cm+dyn.shield
Centroid [channel] P/V FWHM [channel] signal [mV]
N/A
Tube A angle=45
1 2 3 4 51
10
100
1000
10000Tube A angle=90
1=ref 2=no shield 3=1cm shield 4=2cm shield 5=2cm+dyn.shield
P/V FWHM [channel] centroid [channel] signal [mV]
PTG, JS, et al., (JYFL, Finland) Electron Specroscopy at JYFL Daresbury 2.9.2005 19 / 20
Introduction Magnetic Field Simulations Efficiency Tests Stray Field Vs. BGO WDWGFH?
Where Do We Go From Here?
More Simulations (2D/3D) FEMM/RADIA
Build Prototype
Test Efficiency
Detector Design
Infrastructure - Cooling/Support/TargetChamber....
PTG, JS, et al., (JYFL, Finland) Electron Specroscopy at JYFL Daresbury 2.9.2005 20 / 20