1. CAT of AGATA detectors &
AGATA Week July 2008
CAT of AGATA detectors &
The AGATA triple
cluster detector
University of Cologne
Andreas Wiens
B. Birkenbach, B. Bruyneel, J. Eberth, H. Hess, D. Lersch, G. Pascovici, P. Reiter - IKP Cologne
H.-G. Thomas - CTT

2. Overview Acceptance test results
Status of the triple cluster detectors
Crosstalk in triple cluster detector
Summary

3. Experimental setup & specifications
Core
at 1.3MeV: ≤ 2.35keV
at 122keV: ≤ 1.35keV
Segments
at 1.3MeV: ≤ 2.30keV, mean ≤ 2.10keV
at 60keV: ≤ 1.30keV, mean ≤ 1.20keV
Crosstalk ≤1‰

4. Test results A002 & A003 after gluing core contact
A002 detector accepted
A003 detector accepted

5. Test results C004
detector accepted

6. Test results A004 Very good performance at low energies
back seg. F5
FWHM:
2.66 keV
front seg. A1
Very good performance at low energies
low impurity concentration:
crystal properties? trapping?
detector rejected
FWHM:
2.83 keV

7. Test results B001 Core 6 µs 2,66 2,77 3 µs 2,43 2,45 A3 3,03 3,06 2,44
1,2 MeV
1,3 MeV
Core
6 µs
2,66
2,77
3 µs
2,43
2,45 A3
3,03
3,06
2,44
2,53 C3
2,48
2,16
2,29 C3
leakage current
damage at the contact or the implantation
layer of A3 and C3 ?
detector rejected
2.06 keV
@ 59.5 keV

8. Test results B004 First delivery: Dec 08
B004 – missing segment F6 after first delivery
Second delivery: Jun 08
59.5/122 keV FWHM: 1.5/1.6 keV
@ MeV FWHM: 2.7 keV
High noise level at segment F4
(100 mV after Amp, without HV)
60 keV
122 keV
Core
6 µs
1.5
1.6
3 µs
1.55 F4
1.9
1.87
Segments of sector F grounded:
MeV FWHM: 2.72 keV
FWHM:
1.74 keV
@ 122 keV
Core
5000 V

9. C001 in new TU Munich cryostat delivered to Liverpool for scanning
Mean 60 keV:
May 06: /- 63 eV
Jan 08: /- 61 eV
Mean 1.3 MeV:
May 06: /- 0.1 keV
Jan 08: /- 0.1 keV

10. Summary acceptance tests
B001
06/07
Padova
Rejected - damage of contacts of segments A3 & C3
A002
München
Accepted
C004
09/07
Ankara
A004
Rejected - low impurity concentration and/or trapping
A003
10/07
Liverpool
B004
12/07
Tested, not in specification
A005
Uppsala
Test ongoing (Saclay & Cologne)
C005
Test at Saclay
B005
07/08
Test at Cologne

11. Asymmetric AGATA Triple Cryostat
Mechanical precision of the end caps
bending under vacuum within
tolerances
Exact positioning of the detectors
inside the triple endcap
Spacing 0.5 mm
LN2 consumption
Thermal properties
HV box fits
Tolerances spacing between crystals 0.5mm
Tolerances endcaps 0.5mm ?
Temp 55deg
(14h) LN2

12. Tripel Cluster 1 Energies: Single vs Triple cryostat
Resolution 60keV line
Resolution 1.33MeV line
A001 – FWHM [keV]
Excellent energy resolution in new triple cluster
Mean values 60 keV :
A001 : /- 53 eV
B002 : /- 70 eV
C002 : /- 63 eV
especially at low energies (electronic noise):
- glued detector  less microphonics
- HEKO  AGATA preamp
- electronic assembly (grounding, cabling)
B002 – FWHM [keV]
C002 – FWHM [keV]
Improved energy resolution especially at low energies (electronics dominated)
- glued detector less microphonics
- final preamp
electronic assembly (grounding, cabeling)
Message : better than in single cryostat – specification easily met

13. X Cross talk : intro Core to seg Xtalk = understood! Segment labeling:
Sectors: A...F
Rings: 1...6
Core to seg Xtalk
= understood!
A2..A6 B1 F1 X

14. Smallest capacities in ring 2D2 C2 A2 B2 E2 F2

15. Smallest capacities in ring 2B2 C2 E2 F2 D2 A2

17. No cross talk between detectors in Triple Cryostat
Sector A
Sector F
Sector A
Sector F
Core B
Core C
Sector A
Sector F
B002
Core A
Core C
C002
Core A
Core B

18. Tripel Cluster 2 Energies: Single vs Triple cryostat
Resolution 60keV line
Mean values 60 keV :
A001 : /- 65 eV
B002 : /- 73 eV
C002 : /- 105 eV
preliminary

19. AGATA Triple Clusters: Summary and outlook
AGATA Triple Cluster Detectors operational:
first triple:
cryostat, mechanics, vacuum o.k.
seg-preamps, core preamp & pulser o.k.
energy resolution o.k.
no cross talk between detectors
second triple: commissioning phase -
Outlook: Demonstrator at Legnaro:
- transport to Legnaro of ATC1
in July 2008
- assembly of third triple
constrained by available detectors
ATC1
ATC2
ATC3

20. Core pulser result: measurement of segment capacities in 1. triple