Analysis of a g a t a coincidence line scan data
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Analysis of A G A T A coincidence line-scan data. M.Dimmock [email protected] Overview. Radial coincidence data. Effective segmentation issues. Filtering process - sidescan. Comparison of experimental and theoretical pulse-shapes. Analysis summary. Future scans.

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Analysis of A G A T A coincidence line-scan data

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Analysis of a g a t a coincidence line scan data

Analysis of AGATA coincidence line-scan data

M.Dimmock

[email protected]


Analysis of a g a t a coincidence line scan data

Overview

  • Radial coincidence data

  • Effective segmentation issues

  • Filtering process - sidescan

  • Comparison of experimental and theoretical pulse-shapes

  • Analysis summary

  • Future scans


Analysis of a g a t a coincidence line scan data

Experimental data

NaI energy (keV)

Ge core energy (keV)

  • 3 radial line-scans, 2mm spacing, 12 hours / position

30o

15o

0o

  • Gate on 374keV Ge and 288keV NaI energy

  • Gate on segment energy

  • Filter bad events


Analysis of a g a t a coincidence line scan data

Signal noise

  • CWC converter box fault - FIXED for Cologne triple cluster experiment

  • Reduction in noise aides IC and real pulse parameterisation

1 event = 7.84keV (0.78mV)

<100 events> = 3.15keV (0.32mV)

  • pk2pk noise

1 event = 2.77keV (0.27mV)

<100 events> = 1.11keV (0.11mV)

  • RMS noise


Analysis of a g a t a coincidence line scan data

Problem ! ! !

E6

E5

E4

E3

E2

E1

  • Gating on Ge and NaI energies, when each NaI covers multiple depths, does not work for complex segmentation


Analysis of a g a t a coincidence line scan data

Filtering multiple depths

  • Gate on appropriate rise time distributions to split the pulses

  • Add back pulses with small chi-squared – future work !!!

  • Exp seg cross-over:

  • 0o = ~18mm

  • 15o = ~18mm

  • 30o = ~18mm

  • ~100 events in each super-pulse

  • MGS seg cross-over:

  • 0o = 16mm

  • 15o = 18mm

  • 30o = 18mm


Analysis of a g a t a coincidence line scan data

Cs – 137 Side scan

  • Uniform 662keV energy response

  • Segment E3 double peaking

  • Warping of E-filed lines toward central anode

Core response

Core response, ring gated

100

90

80

70

60

50

40

30

20

10

0

0

10

20


Analysis of a g a t a coincidence line scan data

Side scan Projection

  • 15.5mm collimation depth: E1 6-16mm, E2 18-34mm

  • Reduced effective E2 segment volume

~17mm

Segment energy gated response

E1

E2

E3

E4

E5

E6


Analysis of a g a t a coincidence line scan data

6.0 mm

45.5 mm

28.5 mm

15.5 mm

Segment pulses

Centre contact pulses


Analysis of a g a t a coincidence line scan data

Segment pulses

6.0 mm

45.5 mm

28.5 mm

15.5 mm

Centre contact pulses


Analysis of a g a t a coincidence line scan data

15.5 mm

6.0 mm


Analysis of a g a t a coincidence line scan data

Centre contact pulses

Segment pulses

45.5 mm

28.5 mm


Analysis of a g a t a coincidence line scan data

  • Shift in core T90 minimum due to the size of the electrode.


Analysis of a g a t a coincidence line scan data

Analysis Summary

  • Singles and coincidence data agrees well – offset expected due to multiple scattering

  • Improvements required for super-pulses with < 100 events – Generation of singles super-pulses to understand singles data close to the core

  • Superpulses are a promising method for initial parameterisation – This analysis is not possible in real-time PSA – NOISE reduction is crucial


Analysis of a g a t a coincidence line scan data

  • MGS segment pulse shapes will agree well when the lattice orientation is corrected

  • Results are promising for the generation of a basis data set.

  • Move to 1mm diameter injection collimator – will help resolve ambiguities at segmentation boundaries


Analysis of a g a t a coincidence line scan data

Future Measurements

  • Plan for 2006:

    • Coincidence scan each of the 3 symmetric detectors.

    • Compare results between Liverpool, Orsay and GSI scanning system results

  • Scan the first asymmetric detector.

  • All data to be distributed via Orsay.


Changes to liverpool scanning system for 2006

Changes to Liverpool Scanning system for 2006:

  • Utilise 12cm long 1mm injection collimator.

  • First 3 z-depths 1.3mm/back 2.6mm

  • Unique scintillator ring for each depth

  • Change 11.1 MBq (70PP cps) @2mm 9cm [50/2]

    •  70.2MBq 137Cs (40PP cps) [20/1] or

    •  920MBq 137Cs (420PP cps) [200/10]

  • Will allow half of the detector to be scanned in coincidence.

  • Will perform 241Am side scan to determine segmentation boundaries.


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