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Detector Characterisation Group A.Boston and the Liverpool group CCLRC Daresbury Laboratory Characterisation Group Preliminary report on AGATA detector.

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Presentation on theme: "Detector Characterisation Group A.Boston and the Liverpool group CCLRC Daresbury Laboratory Characterisation Group Preliminary report on AGATA detector."— Presentation transcript:

1 Detector Characterisation Group A.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

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

3 Detector Characterisation Group 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

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

5 Detector Characterisation Group AGATA detector measurements 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 Detector Characterisation Group AGATA detector – segment labelling 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. E1 E6 E5 E4 E3 E2 F6 F5 F4 F3 F2 F1 A1 A2 A3 A4 A5 A6 B4 B3 B2 B1 B6 B5 C3 C2 C1 C6 C5 C4 D2 D1 D6 D5 D4 D3 Back face Front face A5 A4 A2 A A B C D E F

7 Detector Characterisation Group AGATA cabling scheme 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 Front Back

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

9 Detector Characterisation Group 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.

10 Detector Characterisation Group AGATA MWD energy resolution results Results from GRT4 MWD. 13.5s peak separation8.0 s Shaping time 5.5 s trapezoid width7.8 s Peak sample time 53 s decay time constant

11 Detector Characterisation Group AGATA – Example poor performance Poor performance with MWD 25 2

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

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

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

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

16 Detector Characterisation Group GRT4 Energy correlation 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 Detector Characterisation Group 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?

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

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

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

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

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

23 Detector Characterisation Group AGATA Detector Pulse shapes Arbitrary Units

24 Detector Characterisation Group AGATA Detector Pulse shapes Arbitrary Units

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

26 Detector Characterisation Group AGATA singles scan Detector response vs depth: 662 keV on core Any energy on segments

27 Detector Characterisation Group AGATA singles scan Detector response vs depth: 662 keV on core 662keV energy on segments

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

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

30 Detector Characterisation Group Detector Issues

31 Detector Characterisation Group

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

33 Detector Characterisation Group Segments 2&27 – counts (695 bkgrd) Segments 3&21 – counts (1235 bkgrd) Segments 7&25 – (1124 bkgrd)

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

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

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

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

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

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

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

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

42 Detector Characterisation Group Cross talk problems Illustration of problems

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

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

45 Detector Characterisation Group AGATA singles scan – T30 vs depth

46 Detector Characterisation Group AGATA singles scan – T90 vs depth

47 Detector Characterisation Group 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

48 Detector Characterisation Group 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.

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

50 Detector Characterisation Group What data was recorded? Coincidence data was recorded on three lines and three radii. 2mm steps. The data was recorded to SDLT tape. 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 Detector Characterisation Group Coincidence scan. 2mm collimator 0.3mCi 137 Cs 3mm mm

52 Detector Characterisation Group AGATA coincidence 0 34mm 44mm 53.38mm 66.26mm 83.14mm mm mm 80mm mm Dead layer including Al can

53 Detector Characterisation Group 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 : 0 O 26mm / 12 hours per position –Line 2 : 15 O 26mm / 12 hours per position –Line 3 : 30 O 26mm / 12 hours per position The z depths are:  1 st depth = mm  2 nd depth = – 17.26mm  3 rd depth = – 30.14mm  4 th depth = – 47.02mm  5 th depth = – 63.9mm  6 th depth = – 82.43mm

54 Detector Characterisation Group 288 keV 374 keV 662 keV 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 Coincidence setup

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

56 Detector Characterisation Group Region of Interest Ge Energy NaI Energy 374 keV 288 keV Coincidence results 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.

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

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

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

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

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

62 Detector Characterisation Group 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.


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