Characterisation A Boston

Detector Characterisation Group
A. Boston and the Liverpool group
CCLRC Daresbury Laboratory
Characterisation Group
Preliminary report on AGATA detector #1
Detector Characterisation Group
• Full characterisation of prototype crystal
– Detailed source scans
– Coincidence measurement
AGATA prototype triple cluster
Detector Characterisation Group
90 × 80 mm
10º tapering angle
• Prototype symmetric triple cluster
• Ordered from CE
• Segmentation scheme 8, 13, 15, 18, 18, 18 mm
AGATA data analysis summary
• A number of measurements have been made:
• Analogue energy resolution results
Detector Characterisation Group
– 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
AGATA detector scanning
Detector Characterisation Group
• Detector scans
• MRD26 connector blocks
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
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.
Detector Characterisation Group
• The core is channel 37.
Back
Front
7 12
1 6
2
5
3 4
8
11
9 10
13
14
18
17
15 16
19
20
24
23
21 22
25 30
26
29
27 28
31 36
32
35
33 34
Digital Pulse Shape Processing
Detector Characterisation Group
• 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.
AGATA energy resolution results
Detector Characterisation Group
Seg ID
A1
B1
C1
D1
E1
F1
A2
B2
C2
D2
E2
F2
A3
B3
C3
D3
E3
F3
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
Energy
[keV]
2.40
1.93
2.75
1.98
2.04
2.80
2.73
2.05
1.99
2.73
2.31
1.97
2.17
2.07
2.08
2.09
1.98
1.90
Seg ID
A4
B4
C4
D4
E4
F4
A5
B5
C5
D5
E5
F5
A6
B6
C6
D6
E6
F6
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
Energy
[keV]
2.69
1.94
2.87
2.59
2.07
2.19
4.08
2.48
2.52
2.61
1.91
2.16
2.04
2.10
1.81
2.24
1.89
2.05
• Best energy resolution results from AGATA
• Segment problems >2.8 keV A5 / C4 / F1
AGATA energy resolutions
• Summary of best values for energy resolution from AGATA
detector.
Detector Characterisation Group
A
B
C
D
E
F
1
2.40
1.93
2.75
1.98
2.04
2.80
Rings
2
2.73
2.05
1.99
2.73
2.31
1.97
3
2.17
2.07
2.08
2.09
1.98
1.90
4
2.69
1.94
2.87
2.59
2.07
2.19
5
4.08
2.48
2.52
2.61
1.91
2.16
6
2.04
2.10
1.81
2.24
1.89
2.05
Sectors
AGATA energy analogue vs digital
6
Detector Characterisation Group
Energy res [keV]
5
4
Analogue
Digital
3
2
1
0
0
1
2
3
4
5
Segment number
• Typical results -> specifically for sector F.
6
7
Automated Scanning Tables
Liverpool System
Detector Characterisation Group
•
•
•
•
•
Parker linear positioning table
Pacific scientific stepper motors
0.3mCi 137Cs/0.2mCi 57Co
1-2mm collimator
Singles/coincidence system
Precise position
calibration
GSI / CSNSM Orsay
Example traces
Detector Characterisation Group
• Typical example of from
detector for the singles
scan measurement
Arbitrary Units
Detector Characterisation Group
AGATA Detector Pulse shapes
20
21
22
26
27
28
32
33
34
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 137Cs source
300Gb of data on SDLT tape
AGATA singles scan
1
2
6
3
5
4
7
8
Detector Characterisation Group
24
12
9
18
11
13
17
10
14
16
30
15
36
19
23
25
29
31
35
20
22
26
28
32
34
21
27
• Detector response vs depth: 662 keV on core
• Any energy on segments
33
AGATA singles scan
1
2
6
3
5
4
7
8
Detector Characterisation Group
24
12
9
18
11
13
17
10
14
16
30
15
36
19
23
25
29
31
35
20
22
26
28
32
34
21
27
• Detector response vs depth: 662 keV on core
• 662keV energy on segments
33
Scattering / Cross talk results
2 (B1) – 27 (C5)
34085 counts
(695 bkgrd)
Detector Characterisation Group
7 (A2) – 25 (A5)
132227 counts
(1124 bkgrd)
3 (C1) – 21 (C4)
164556 counts
(1235 bkgrd)
• Multiplicity two scatter plot for AGATA segments (singles scan)
Detector Characterisation Group
AGATA singles scan : Core risetime results
T30
T90
T60
Centre contact
risetime results
Detector Characterisation Group
AGATA singles scan – T30 vs depth
Detector Characterisation Group
AGATA singles scan – T90 vs depth
Detector Characterisation Group
Coincidence measurement
• Sector E has been scanned – singles intensity profile.
What data was recorded?
Detector Characterisation Group
• 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)
AGATA coincidence
80mm
90
118.55mm
18
72
18
54
18
36
Detector Characterisation Group
15
21
13
8
8
36
100.02mm
83.14mm
66.26mm
53.38mm
44mm
34mm
0
3mm Dead layer including Al can
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
Detector Characterisation Group
• 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:
1st depth = 5 - 7.88mm
2nd depth = 14.38 – 17.26mm
3rd depth = 27.26 – 30.14mm
4th depth = 44.14 – 47.02mm
5th depth = 61.02 – 63.9mm
6th depth = 79.55 – 82.43mm
Coincidence setup
Detector Characterisation Group
374
keV
288
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
Detector Characterisation Group
Coincidence results
• Coincident response in segment E2 (11) and E4 (23)
288 keV
Detector Characterisation Group
NaI Energy
Coincidence results
Region of Interest
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.
Ge Energy
– This leaves ~ 400Mb of data
per line.
Coincidence measurements
400
350
Detector Characterisation Group
Number of true coincidences
300
250
E1
E2
E3
E4
200
150
100
50
0
1
2
3
4
5
6
7
8
9
10
11
12
Step number [2mm]
• 18mm radius / 2mm steps over 80O (-10O  +70O)
• Total distance moved 26mm / 10 hours per position
13
Coincidence measurement
800
700
Number of true coincidences
600
500
E1
E2
E3
E4
400
300
Detector Characterisation Group
200
100
0
4
6
8
10
12
14
16
18
20
22
24
26
28
30
Radius [mm]
• Radial scan : line 1 : 12 hours per position
32
34
36
38
40
AGATA summary
• The detector has been scanned.
• Data is available:
Detector Characterisation Group
– 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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