1. Detector Characterisation Group
Boston and the Liverpool group
CCLRC Daresbury Laboratory
Characterisation Group
Preliminary report on AGATA detector #1
Full characterisation of prototype crystal
Detailed source scans
Coincidence measurement
Detector Characterisation Group

2. AGATA prototype triple cluster
90 × 80 mm
10º tapering angle
Detector Characterisation Group
Prototype symmetric triple cluster
Ordered from CE
Segmentation scheme 8, 13, 15, 18, 18, 18 mm

3. AGATA data analysis summary
A number of measurements have been made:
Analogue energy resolution results
A 370kBq 60Co source was placed near the detector.
An Ortec 671 Spectroscopy amplifier was used with 6us of shaping to produce energy resolutions.
The count rate was <1000cps.
The core energy resolution was measured to be 2.6 keV.
Efficiency measurement
Digital electronics
Energy resolution
Scattering / Addback
Singles scan
Coincidence scan
Detector Characterisation Group

4. AGATA detector scanning
Detector scans
MRD26 connector blocks
Detector Characterisation Group

5. AGATA detector measurements
Detector Characterisation Group
Performance tests of the AGATA prototype detector.
Fitted with GANIL differential preamplifiers
CWC differential to single ended converters (manufactured at TU Munich) used to provide single ended signal to electronics.
GRT4 digital electronics cards

6. AGATA detector – segment labelling
Back face A5 A1 A2 A3 A4 A5 A6 B4 B3 B2 B1 B6 B5 C3 C2 C1 C6 C5 C4 D2 D1 D6 D5 D4 D3 E1 E6 E5 E4 E3 E2 F6 F5 F4 F3 F2 F1 6 5 4 3 2 1 A4 A2 A1
A B C D E F
Detector Characterisation Group
Front face
The above plot shows the labelling of the segments on the first AGATA prototype module.
Note the confusing scheme (all segs offset by 1)!
Errors on can labelling are indicated in red.
Our cabling philosophy shown in green.

7. AGATA cabling scheme Back Front
AGATA detector connected to CWC modules through 7 MRD cable cables.
37 BNC > SMA cables connect to GRT4 modules.
The cabling scheme groups segments in rings:
1-6 ring 1
7-12 ring 2 etc.
The core is channel 37.
Detector Characterisation Group 1 2 3 4 6 5 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
Front
Back

8. AGATA energy resolution results
Detector Characterisation Group
Analogue energy resolution results from AGATA
Segments problems A1 / A4 / A5 / B5 / C4 / D2 / D5 / F1

9. Digital Pulse Shape Processing
GRT 4 cards with 80Mhz sampling 14bit dynamic range
The cards now have MWD implemented, courtesy of Ian Lazarus and Martin Lauer.
Digital CFD is implemented.
Common card time stamping (48bit) is implemented.
Detector Characterisation Group

10. AGATA MWD energy resolution results
Detector Characterisation Group
Results from GRT4 MWD.
13.5s peak separation 8.0 s Shaping time
5.5 s trapezoid width 7.8 s Peak sample time
53 s decay time constant

11. AGATA – Example poor performance2 25
Detector Characterisation Group
Poor performance with MWD

12. AGATA energy resolution results
Detector Characterisation Group
Best energy resolution results from AGATA
Segment problems >2.8 keV A5 / C4 / F1

13. AGATA energy resolutions
Summary of best values for energy resolution from AGATA detector.
Detector Characterisation Group
Rings
Sectors

14. AGATA energy analogue vs digital
Detector Characterisation Group
Typical results -> specifically for sector F.

15. GRT4 time stamping problems
Detector Characterisation Group
There are problems with the time stamp on two GRT cards.
Plot shows time different between core and segment time stamp.

16. GRT4 Energy correlation
Detector Characterisation Group
There were issues with the GRT 4 MWD code. A peak separation of >13us gives uncorrelated data.
The plots above show MWD vs baseline difference energies.

17. GRT4 energy performance
The energy resolution performance for the GRT4 MWD algorithm was assessed with the AGATA detector.
Typical response for the centre contact is illustrated.
What is the cause of this tailing?
Detector Characterisation Group

18. GRT4 energy performance
Detector Characterisation Group
MWD baseline
Produce a plot of the energy derived from MWD vs the FADC baseline value.
Is this tailing DNL?  The effect is count rate dependent.

19. GRT4 energy performance
It would be good to add martin lauers obesrvations here
BRING HOME MARTINS THESIS
ADD HERE
Detector Characterisation Group

20. GRT4 energy performance
Options:
Gate on the “true peak”
Attempt to correct for effect linear? Energy dependent? Count rate dependent?
Detector Characterisation Group

21. Automated Scanning Tables
Liverpool System
Parker linear positioning table
Pacific scientific stepper motors
0.3mCi 137Cs/0.2mCi 57Co
1-2mm collimator
Singles/coincidence system
Detector Characterisation Group
Precise position
calibration
GSI / CSNSM Orsay

22. Example traces
Typical example of from detector for the singles scan measurement
Detector Characterisation Group

23. AGATA Detector Pulse shapes20 21 22 26 27 28
Arbitrary Units
Detector Characterisation Group 32 33 34

24. AGATA Detector Pulse shapes20 21 22 26 27 28
Arbitrary Units
Detector Characterisation Group 32 33 34

25. AGATA detector scan AGATA singles scan
Detector Characterisation Group
AGATA singles scan
Intensity map for 662keV interaction on centre contact
2mm collimator / 2 minutes per position
0.3mCi 137Cs source
300Gb of data on SDLT tape

26. AGATA singles scan 18 12 6 1 5 7 11 13 17 2 4 8 10 14 16 9 3 15 24 30 36 19 23 25 29 31 35
Detector Characterisation Group 20 22 26 28 32 34 21 27 33
Detector response vs depth: 662 keV on core
Any energy on segments

27. AGATA singles scan 18 12 6 1 5 7 11 13 17 2 4 8 10 14 16 9 3 15 24 30 36 19 23 25 29 31 35
Detector Characterisation Group 20 22 26 28 32 34 21 27 33
Detector response vs depth: 662 keV on core
662keV energy on segments

28. Segment Multiplicity The number of segments firing in coincidence:
Detector Characterisation Group
The number of segments firing in coincidence:
Defined as MWD energy above trigger.

29. Segment Multiplicity The number of segments firing in coincidence:
Detector Characterisation Group
The number of segments firing in coincidence:
Defined as energy > 3sd of baseline noise.

30. Detector Issues
Detector Characterisation Group

31. Detector Characterisation Group

32. Scattering / Cross talk results
2 (B1) – 27 (C5)
34085 counts
(695 bkgrd)
7 (A2) – 25 (A5)
counts
(1124 bkgrd)
Detector Characterisation Group
3 (C1) – 21 (C4)
counts
(1235 bkgrd)
Multiplicity two scatter plot for AGATA segments (singles scan)

33. Segments 2&27 – 34085 counts (695 bkgrd)
Segments 7&25 – (1124 bkgrd)
Detector Characterisation Group

34. Scattering : What is the cause of this tailing?
Detector Characterisation Group
Low energy tailing – not consistent with energy algorithm

35. Scattering : What is the cause of this tailing?
Detector Characterisation Group
Suppression of 2 – 27 scatters removed low energy tail.

36. AGATA – Addback rings Addback – confined a concentric rings
Detector Characterisation Group
Addback – confined a concentric rings

37. AGATA – Addback sectors
Detector Characterisation Group
Addback - confined to sectors

38. Cross talk problems Large number of counts with low energy in B1
Detector Characterisation Group
Cross talking segments 2 (B1)  27 (C5)

39. Cross talk problems B1  C5 / C1  C5 A2  A5
Detector Characterisation Group
Cross talk B1  C5 / A2  A5 / C1  C4

40. Cross talk problems Double hit addback confined to sectors
Detector Characterisation Group
Double hit addback confined to sectors

41. Cross talk problems Rejecting 3(C1)  21(C3)
Detector Characterisation Group
Rejecting 3(C1)  21(C3)

42. Cross talk problems Illustration of problems
Detector Characterisation Group
Illustration of problems

43. AGATA singles scan : Core risetime results
Detector Characterisation Group
T30
T60
Centre contact
risetime results
T90

44. AGATA singles scan : Core risetime results
Detector Characterisation Group
T30
T60
T90
Centre contact
risetime results
662keV segments

45. AGATA singles scan – T30 vs depth
Detector Characterisation Group

46. AGATA singles scan – T90 vs depth
Detector Characterisation Group

47. Risetime Results : Summary
What do we need?
Look at outer contact risetimes
Are the segment risetimes well aligned?
What is the profile?
Can we use these values along with the core
Outer contact image charge response
Image charge asymmetry vs position of scanning table
Detector Characterisation Group

48. Coincidence scan
Insert picture of sector to be scanned and the lines, along with the radii.
Insert slide with “what is available” and how large
Insert slide with geometry of scanning assembly
Exact dims
Collimator spread results
Insert typical statistics example vs radius depth
Insert typical quality example
Show some pictures.
Detector Characterisation Group

49. Coincidence measurement
Detector Characterisation Group
Sector E has been scanned – singles intensity profile.

50. What data was recorded?
Coincidence data was recorded on three lines and three radii.
2mm steps.
The data was recorded to SDLT tape.
Detector Characterisation Group
Position from scanning table and step number
High resolution energy from core and NaIs from Silena ADCs
TAC of Ge core vs NaI firing.
GRT 4 data from 37 channels (512 samples 80Mhz)

51. . Coincidence scan 2.88mm 16.00 15.65 14.00 6.5 10.00 3mm 0.3mCi 137Cs
Detector Characterisation Group
3mm .
2mm collimator
0.3mCi 137Cs

52. AGATA coincidence 80mm 118.55mm 100.02mm 83.14mm 66.26mm 53.38mm 44mm90 18
118.55mm 72 18
100.02mm 54 18
83.14mm 36 15
66.26mm 21
Detector Characterisation Group 13
53.38mm 8 8
44mm
34mm 36
3mm Dead layer including Al can

53. AGATA coincidence
Coincidence data has been recorded along 3 lines and 3 radii inside sector E of the detector.
The data is in rings w.r.t. centre (x,x):
Ring 1 : 28mm radius / 6 hours per position
Ring 2 : 23mm radius / 8 hours per position
Ring 3 : 18mm radius / 10 hour per position
In lines
Line 1 : 0O 26mm / 12 hours per position
Line 2 : 15O 26mm / 12 hours per position
Line 3 : 30O 26mm / 12 hours per position
The z depths are:
Detector Characterisation Group
1st depth = mm
2nd depth = – 17.26mm
3rd depth = – 30.14mm
4th depth = – 47.02mm
5th depth = – 63.9mm
6th depth = – 82.43mm

54. Coincidence setup
Utilises a multi-leaf collimator to measure six depths simultaneously.
2mm injection
2mm ring collimators
Typical count rates for outer radii
Singles Ge >60keV : 500 c/s
Coincidence : 50 c/min
True Coincidence : 25 c/hour
288
keV
374
662
Detector Characterisation Group

55. Coincidence results Coincident response in segment E2 (11) and E4 (23)
Detector Characterisation Group
Coincident response in segment E2 (11) and E4 (23)

56. Coincidence results Region of Interest Ge Energy NaI Energy 374 keV
Matrix of Ge energy vs Total NaI derived from Silena ADCs
The region of interest for “true” coincidences is highlighted in red.
The data was presorted to keep only the data in this region.
This leaves ~ 400Mb of data per line.
Detector Characterisation Group

57. Coincidence measurements
Detector Characterisation Group
Double peaking on segment 17 (E3)

58. Coincidence measurements
Detector Characterisation Group
28mm radius / 2mm steps over 80O (-10O  +70O)
Total distance moved 40mm / 6 hours per position

59. Coincidence measurements
Detector Characterisation Group
18mm radius / 2mm steps over 80O (-10O  +70O)
Total distance moved 26mm / 10 hours per position

60. Coincidence measurement
Detector Characterisation Group
Radial scan : line 1 : 12 hours per position

61. Coincidence measurement
Detector Characterisation Group
Radial scan : line 2 : 12 hours per position

62. AGATA summary The detector has been scanned. Data is available:
Singles data 300Gb
Coincidence data
The detector performance was reasonable. Improvements are possible.
Detail will be discussed in the detector characterisation group meeting this afternoon.
Detector Characterisation Group