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Published byMay Arnold Modified over 9 years ago
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PRESORT OF THE DATA OF THE COLOGNE TEST EXPERIMENT ● Quality and integrity of data ● Detector numbering and positions ● Calibrations and gain stability ● Reactions channels identification
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The experiment Main characteristics of the setup BEAM 48 Ti100 MeV TARGET 48 Ti + 2 H220 μg/cm 2 Si detector thickness300 μm segmentatio n 32 rings, 64 sectors Absorberthickness16 μm (Al) AGATA symmetric triple-cluster
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What to check ● Quality and integrity of data – Sector energies mostly missing – Some segments are in short circuit and other are missing ● Detector numbering and positions ● Calibrations and gain stability ● Reactions channels as expected ?
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Quality and integrity of data validation Silicon detector fires with almost all his sectors and rings every event The time of a lot of channels is in overflow We can ask for a validation with an autocoincidence After validation the multiplicity of sectors and rings is (1, 1) as expected for the reaction TDC of silicon detector
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Quality and integrity of data real gate validation TDC of silicon detector TDC of germanium detector
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Quality and integrity of data With gate on sector energy Without gate on sector energy
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Quality and integrity of data 3 segments in short circuit 2 segments in short circuit Some segments missing/low statistics
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What to check ● Quality and integrity of data ● Detector numbering and positions – Ring numbering – Sector numbering – Silicon detector position ● Calibrations and gain stability ● Reactions channels as expected?
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Geometry – ring numbering Counts on the rings ~ ring solid angle Tape number 19: alpha source ● Inverse numbering of the rings ● The distance between the source and the silicon detector is 34 mm (what about the target?)
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Geometry – sector numbering Depends on the angle of the firing sector 49 Ti: 1381 keV 48 Ti: 983 keV The Doppler correction depends also on: the mass of the scatterer nucleus the reaction mechanism
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Geometry – sector numbering x y 12.3 ± 0.5 deg 0 8 16 24 32 40 48 56 63 FRONT view (from the target) Center of the cluster in the yz plane Ge detectors E γ – sector #
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Geometry – silicon detector position BEAM IS OFF AXIS DISTANCE: 2.67 ± 0.01 mm DIRECTION: 100.4 ± 0.1 deg (~ direction of sector 19) Center of silicon detector Beam position SI DETECTOR IS NOT PERPENDICULAR TO BEAM ANGLE (θ): 4.50 ± 0.02 deg DIRECTION (φ): 100.4 ± 0.1 deg (~ direction of sector 19) OR beam Si det Target R int = 16.5 mmd = 2.7 mm θ = 4.5 deg ring # – sector #
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What to check ● Quality and integrity of data ● Detector numbering and positions ● Calibrations and gain stability – DGF stability ● Reactions channels as expected?
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Electronics stability DGF gain stability: ● rough calibration using 60 Co sources ● fine recalibration using 511 keV peak during run with beam
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What to check ● Quality and integrity of data ● Calibrations and gain stability ● Detector numbering and positions ● Reactions channels as expected? – (d,p) 49 Ti – (d,d’) and (d,pn) 48 Ti – Other reaction channels ?
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Channel identification: gamma spectrum Gammas from 49 Ti
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Channel identification: (d,p) through direct reaction Q value of (d,p) reaction: 5.92 MeV Excitation energy: 6.2 MeV keV
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Channel identification: (d,p) through fusion evaporation PACE calculation: proton spectrum in CM PACE Coulomb barrier: 3.95 MeV Proton with 4.5 MeV in CM 4.5 3.5 5.5 6.5
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Channel identification: gamma spectrum Gammas from 49 Ti and 48 Ti
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Channel identification: (d,d') direct and (d, pn) fusion evaporation (d,d’) direct (d,pn) fusion-evaporation (?) Gate on gamma energy 983 keV
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Channel identification: other reaction channels ? Gate on gamma energy 983 keV Protons and deuterons can not deposit so much energy Is it noise? Why only at small angles?
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48 Ti 2H2H Channel identification: other reaction channels ?
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16 O 12 C Channel identification: other reaction channels ?
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12 C 14 N 16 O Channel identification: other reaction channels ? Absorber thickness: 16 µm ABSORBERNUCLEUS 6 µm 48 Ti 10 µm 27 Al 16 µm 16 O 18 µm 14 N 21 µm 12 C logbook
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Channel identification: other reaction channels ?
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Low energy High energy ? Time correlation between high and low energy events in si-detector Concentration of impurities increases with time High concentration of low energy events in tape 15 and 16 not understood Channel identification: other reaction channels ? new target (chamber opened) changed Si-HV and threshold
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Overflow is expected here but there is not! Channel identification: other reaction channels ?
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Overflow is expected here but there is not! This region has the right: deflection angles gamma spectrum statistical dependence on time Doppler correction Channel identification: other reaction channels ?
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Overflow is expected here but there is not! This region has the right: deflection angles gamma spectrum statistical dependence on time Doppler correction Channel identification: other reaction channels ? This can mean that electronics did not work the way we expected
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Channel identification: other coulex reactions This region has the right: deflection angles gamma spectrum statistical dependence on time Doppler correction This can mean that electronics did not work the way we expected
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Channel identification: statistics and selection mechanis m Gamma energy Energy in silicon detector counts (d,p) direct 1381 keV 750k (d,p)fus-evap 1381 keV (d,d’)direct983 keV< 30k (d,pn)fus-evap983 keV< 15k (HI, HI’)coulex983 keVE > 8 MeV80k (HI, HI’)coulex983 keV2 < E < 8 MeV~ 100k (HI, HI’)coulex983 keV0.3 < E < 2 MeV 140k mixed 220k counts
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Conclusion: what to analyse ? 16 O 12 C Experiment designed for d( 47 Ti, 48 Ti)p direct reaction Beam was 48 Ti No direct reaction on target We still have a nice direct reaction on contaminant(s) ! BUT Smaller statistics Use of background
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Quality and integrity of data
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Quality and integrity of data Data structure Sector #, Energy, Time … Ring #, Energy, Time … Germanium #, Energy, Time … Segment #, Trace, Energy …. Silicon detector Germanium detector VME modules DGF modules
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