Compton Kinematics studies and simulation results

Paola Solevi04/11/2009

Energy distribution

- Run 1665, HL on trigger turned off.- Calibration with 1680 (ET) and 1681 (IT).

1 LYSO only selected. Small tagger guarantees low energy hit are focused at the centre of the module.

General cluster overview with no selection

pp+63 keV

Cluster selection: amplitude [I]

By requiring only 1 cluster on the same layer of the fired LYSO (1 LYSO selected).

Run 01665

Selection for different energy ranges.

Cluster selection: amplitude [II]

By selecting all clusters whose amplitude is larger than a certain threshold (thres = 150 adc cnts * E1/Eme).

Run 01665

Selection for different energy ranges.

Cluster selection: # wls [I]

By requiring only 1 cluster on the same layer of the fired LYSO (1 LYSO selected).

Run 01665

Selection for different energy ranges.

Cluster selection: # wls [II]

By selecting all clusters whose amplitude is larger than a certain threshold (thres = 150 adc cnts * E1/Eme).

Run 01665

Selection for different energy ranges.

Cluster selection: # cluster [I]

By selecting all clusters whose amplitude is larger than a certain threshold (thres = 150 adc cnts * E1/Eme).

Run 01665

Selection for different energy ranges.

Energy distribution

Investigation of the reconstructed z coordinated for different energy ranges.

Run

0166

5

z coordinate for 1 LYSO fired, in different energy ranges, using WLS in cluster selected by Ncluster =1. The shown distribution are obtained by selecting events on layer 6.

The larger is the energy, more WLS are fired and the reconstructed z gets continuous.

Increasing energy

Efficiency study

Investigation of the efficiency of the cluster selection criteria.Ru

n 01

665

Energy[keV]

# events # clusters #cluster after

selection 1

# cluster after

selection 2

Ratio I/II

50-100 8843 1608 1590 1592 99.8

100-150 12195 6434 6274 5993 104.7

150-200 13911 11426 10846 9825 110.4

200-250 11221 10658 9679 9097 106.4

250-300 8544 8603 7392 7444 99.3

300-350 8606 8974 7218 7778 92.8

350-400 5281 5582 4069 4645 87.6

400-450 16924 20704 12802 16323 78.4

450-500 51285 65541 36870 49811 74.0

500-550 1657 2128 1008 1471 68.5

Studying WLS cluster for different WLS thresholdsRun 01665

Dependence on the WLS thr of the number of events with no WLS fired.

Different thresholds have been applied at WLS level: (20), 30, 40, 50 and 60 adc counts.

Run 01665

50-100

Cluster selection: amplitude [I]

30 adc cnts 40 adc cnts 50 adc cnts 60 adc cnts

150-150

150-200

200-250

250-300

300-350

350-400

400-450

450-500

500-550

Run 01665

50-100

Cluster selection: amplitude [II]

30 adc cnts 40 adc cnts 50 adc cnts 60 adc cnts

150-150

150-200

200-250

250-300

300-350

350-400

400-450

450-500

500-550

Ratio bin to bin of cluster selected with and without a threshold applied.

Run 01665

Dependence on the WLS thr of the size of cluster in different energy ranges.

Cluster selection: # wls

30 adc cnts 40 adc cnts 50 adc cnts 60 adc cnts

50-100

150-150

150-200

200-250

250-300

300-350

350-400

400-450

450-500

500-550

Run 01665

Dependence on the WLS thr of the number of cluster in different energy ranges.

Cluster selection: # cluster

30 adc cnts 40 adc cnts 50 adc cnts 60 adc cnts

50-100

150-150

150-200

200-250

250-300

300-350

350-400

400-450

450-500

500-550

Run 01665Study of cluster multiplicity

30 adc40 adc50 adc60 adc

0 cluster

1 cluster

2 cluster

“Cleaned up” simulation: LYSO (Lu = 72%) [1]

I cleaned the source code from all changes done and the agreement with data is eventually good! Now changes have to be re-implemented by comparing data and simulation step after step.

- Small shift due to the calibration.- 63 keV is a bit under-estimated.

“Cleaned up” simulation: LYSO (Lu = 72%) [2]

Understanding the intrinsic radioactivity spectrum

Energy in LYSO with energy blurring: only 300, 200 and 63 keV peaks are visible.

Υ3

Υ3-Kα

Υ2-Kα

Kα

Υ2

Υ1