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


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)



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



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



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)



Conversion Electron Spectroscopy of254No

P.A. Butler et al., PRL89, 202501 (2002)

R.D. Humphreys et al., PRC69, 064324 (2004)



Permanent Magnets

~15cm ~30cm

IronNdFeB 40 MGOe

40mm

100mm



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



Electromagnets - Possible Geometry?




RITU

JUROGAM

SACRED



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



Field Profile 560A



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



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)



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


Tube A=40cm

Tube A offset from BGO centerline 5cmTube C is on BGO center line

Tube C=40cm

(SFC34)


Tube A=30cmTube C=34cm




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




0 1000 2000 30000

1000

2000

3000

4000

5000

6000

7000

HV=1600

C

ount

s

Channel

HV=1500

Reference




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]



Where Do We Go From Here?

More Simulations (2D/3D) FEMM/RADIA

Build Prototype

Test Efficiency

Detector Design

Infrastructure - Cooling/Support/TargetChamber....


Electron Spectroscopy at JYFLnpg.dl.ac.uk/GREAT/sagelisatalks/Paul_Greenlees_sage.pdf · BGO...

Documents

Transcript of Electron Spectroscopy at JYFLnpg.dl.ac.uk/GREAT/sagelisatalks/Paul_Greenlees_sage.pdf · BGO...