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Linear Alkyl Benzene (LAB) Cerenkov and Scintillation Separation
Mohan Li, Zhe Wang Tsinghua University
June 05, 2015
Mohan Li | LAB Cerenkov and Scin>lla>on Separa>on | 06.05.2015 | Page 2
Outline
·Background and Mo>va>on ·Research Method
·Hardware System ·Offline Data Cut
·Result and Analysis ·Future Work Plan
Mohan Li | LAB Cerenkov and Scin>lla>on Separa>on | 06.05.2015 | Page 3
Background and Mo2va2on
• China Jinping Underground Laboratory (CJPL) Neutrino Experiment will use the Cerenkov-‐Scin6lla6on detector. • Water-‐based liquid scin>llator (WBLS) might be the
detec>ng material. • We built a plaYorm for tes>ng the light characteris>c of Linear Alkyl Benzene(LAB), the raw material of WBLS. • It is the first prototype of the new detector. • It could measure the overlapping Cerenkov-‐Scin>lla>on
signal.
Mohan Li | LAB Cerenkov and Scin>lla>on Separa>on | 06.05.2015 | Page 4
Hardware System -‐ Pla<orm
Top PMT
BoBom PMT
µ
LAB
Flash ADC
Op6cal fiber (Connect to PC)
Fig.1 PlaYorm
Mohan Li | LAB Cerenkov and Scin>lla>on Separa>on | 06.05.2015 | Page 5
Hardware System – Structure of the Detector
• Trigger signal – A single ver6cal cosmic µ
Fig.2 Structure of the Detector
4 Coincidence Channels
2 An>coincidence Channels
Mohan Li | LAB Cerenkov and Scin>lla>on Separa>on | 06.05.2015 | Page 6
• Data sample • 4863 events in total. • Event rate is approximately 90/hour.
• Data cut -‐ Coincidence • Cut Peak/Width [V/ns] and Peak/Charge [Ohm/ns].
Offline Data Analysis – Cut in 4 Coincidence Channels
Fig.5 Peak/Charge v.s. Charge Fig.4 Peak/Width v.s. Charge
Cut Cut
Fig.3 An example of an event
Peak Charge (Square) Width(FWHM)
Trigger Time
Trigger Range (40ns)
4 Coincidence channels
2 An>coincidence channels
Top PMT
Bofom PMT
Mohan Li | LAB Cerenkov and Scin>lla>on Separa>on | 06.05.2015 | Page 7
• Data Cut -‐ An>coincidence • Cut Charge Integral [V×ns] in Trigger Range.
Offline Data Analysis – Cut in 2 An2coincidence Channels
Fig.6 Charge distribu>on in 2 an>coincidence channels
Cut Cut
• All the cuts are checked by looking at many events. • Cut result
• 2033 events (41.8%) pass the cuts.
Mohan Li | LAB Cerenkov and Scin>lla>on Separa>on | 06.05.2015 | Page 8
Offline Data Analysis – Cut result
Fig.7 Landau fit of charge in 4
Coincidence channels.
• Landau fit of Charge in 4 Coincidence channels
Mohan Li | LAB Cerenkov and Scin>lla>on Separa>on | 06.05.2015 | Page 9
• Trigger >me correc>on • Let different events have the same Trigger Time.
Fig.8 Add Bofom PMT signals from 22 events into one histogram directly.
Fig.9 The same adding aker Trigger Time correc>on.
Offline Data Analysis – Trigger 2me Correc2on
Mohan Li | LAB Cerenkov and Scin>lla>on Separa>on | 06.05.2015 | Page 10
Fig.10 Add Top PMT signal and Bofom PMT signal from all good events (2033).
Result and Analysis
Bofom PMT
Top PMT
Mohan Li | LAB Cerenkov and Scin>lla>on Separa>on | 06.05.2015 | Page 11
Future Work Plan
• Modify the structure of the liquid box to let PMT7 receive the UV scin>lla>on light.
• Check the reason of the jifer structure and eliminate it.
Ns
NC
gamma
electron
Fig.11 Schema>c diagram of the light yield curve.
• Measure the light yield of Cerenkov light and calculate that of Scin>lla>on light. Draw the light yield curve of of gamma and electron, which could: • Help to discriminate gamma from
electron. • Guide the formula of light sample.
Example: Same Scin>lla>on light, different Cerenkov light
Thank you!