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Tran Duy Tap Le Cong Hao Doan Thi Hien (Nomachi group)

A primer course of experimental particle and nuclear physics . BiPo decay experiment. Tran Duy Tap Le Cong Hao Doan Thi Hien (Nomachi group). OSAKA UNIVERSITY - 2009. OUTLINE. Introduction Principle of measurement Results Summary. Introduction (1). BiPo decay experiment

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Tran Duy Tap Le Cong Hao Doan Thi Hien (Nomachi group)

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  1. A primer course of experimental particle and nuclear physics  BiPo decay experiment Tran Duy Tap Le Cong Hao Doan Thi Hien (Nomachi group) OSAKA UNIVERSITY - 2009

  2. OUTLINE • Introduction • Principle of • measurement • Results • Summary

  3. Introduction (1) • BiPo decay experiment • Set up the CAMAC and FADC to measure the BiPo decay • Principle of measurement  • Time and energy calibrations • Measurement of T1/2 of BiPo decay • Measurement of beta and alpha energy of BiPo events • Measure amount of BiPo decay

  4. Q = 2.2 MeV Long -life Short -life Material to make BiPo detector is called Yunohana powder which contains BiPo decay • Long –life: measured by FDAC • Sort – life: measured by FDAC and CAMAC Introduction (2) Purpose of the BiPo decay experiment is to measure the contamination in 208Tl and 214Bi of the  source foils which are used for double beta decay experiment.

  5. Principle of measurement (1) Yunohana is placed as sandwich of two PMTs Time signature: 1 hit and 1 delay hit PMT A  Time  PMT B Yunohana Paper Yunohana Yunohana is faced to PMT B only, so PMT A only gets electron signal   PMT A PMT B Grease Grease Plastic

  6. Principle of measurement (2) Schematic of data acquisition ADC ADC1 ADC2 PMT A Delay Devider Discrimator Gate Paper Energy measurement A Yunohana TDC Start Stop Devider B Delay Time measurement Discrimator PMT B

  7. Principle of measurement (3) Time and energy measurement PMT A Time PMT B Time measurement by (TDC) Time difference Stop logic Start logic Gate 700 ns Energy measurement by (ADC)

  8. Principle of measurement (4) Set up of the measurement Thickness lead and copper to reduce the background PMT B PMT A • Thickness of lead is 10 cm • Thickness of copper is 5 cm

  9. Principle of measurement (5) NIM CAMAC ADC Scaler TDC Delay Discriminator Time range of TDC:  700 ns

  10. Time calibration (1) • Time calibration is to determine delayed time between two sequence events between two PMTs. • Function generator is used to generate two known delayed-time pulses. DAQ Ch 1 TDC Function Generator Start Stop Ch 2 Time diff.

  11. Time calibration (2) Result of time calibration 1 ch = 20.85 ns

  12. Energy calibration (1) Measuring gamma + beta Measuring gamma Pb collimator Plastic scintillator Pb board Plastic scintillator 207Bi source 207Bi source Gamma ray Beta ray Gamma ray

  13. Energy calibration (2) Energy calibration of PMT A • Red line is gamma spectrum • Black line is gamma-beta spectrum Region difference Gamma-beta spectrum 976 keV Beta spectrum Gamma spectrum

  14. Energy calibration (3) PMTA: • Energy of beta: 976 keV • Channel: 240 4.07 keV/ch Similar, PMTB: 3.75 keV/ch

  15. Results (1) Time measurement by TDC Coincidences Single hit BiPo events • Time to measure is 37.5 h • Counts to get are 51073 • Count rate is 0,378 counts/second Coincidences almost from cosmic ray

  16. Results (2)  Time PMT A BiPo events  PMT B Time PMT A Coincidence PMT B PMT A Time Single hit PMT B

  17. Fitting data as follows: Results (3)

  18. Results (4) Time measurement by TDC Linear fit of the BiPo decay Linear Fit Y = A + B * X Parameter Value Error ----------------------------------------------------- A 2,98279 0,1213 B -0,00249 3,39504E-4

  19. Results (5) • Time to measure is 37.5 h • Counts to get are 51073 • Count rate is 0,378 • BiPo events are 429 • BiPo count rate is 0,003 counts/second

  20. Results (6) Energy measurement by ADC Beta 2200 keV Alpha • Quenching factor = 1/11 • 8 MeV@ = 0.8 MeV@e- 800 keV

  21. Summary • What we do: • Set up the detection of BiPo events • Set up data acquisition using NIM and CAMAC • Measure the half-life of BiPo soft – life decay • Measure the beta and alpha energy of BiPo decay • Measure amount of BiPo sort-life decay • What we feel: • NIM and CAMAC can measure the sort-life of BiPo decay • TDC is actual useful to measure the time difference between beta and alpha signatures • We can learn how to make the logic trigger • NIM and CAMAC in this experiment can’t measure the long-life of BiPo decay due to the limitation of equipment. (time range  700 ns)

  22. BiPo detectorwith FADC Le Cong Hao

  23. 1. Set up FADC system

  24. ADC or TDC FADC Why FADC? We will lose some signal Losing signal By using FADC we will not worry much about it

  25. This is the typical signal form FADC

  26. ( 164 µs ) Main background Short life Long life

  27. Plastic Scintillator α b Understanding of signal collected processing Short life

  28. Long life

  29. Pb 2. Energy calibration PL Gamma spectrum +g +g g e e Bi 207 Beta + Gamma spectrum

  30. 976 Kev After subtract and gauss fitting

  31. 758.7 channel = 976 Kev After subtraction and gauss fitting

  32. 976 Kev

  33. 910.4 channel = 976 Kev After subtraction and gauss fitting

  34. 3. Taking data for Bipo events • Time for taking data: 9h • Number of events: 30000 • visual scaler: 30302

  35. After taking data, we use “Ana” program (Nomachi’s group) and “Paw” (Cern) software for the analysis Bipo events In this experiment we can measure Long and Short Bi-Po events

  36. ~700 Kev ~3.27 Mev ~800 Kev ~2.25 Mev

  37. LongBBtimed 164 us LongABtimed 164 us ShortBBtimed 164 us ShortABtimed 300 ns

  38. Disadvantge There are also some present problems for FADC: • Data size is too large • Event selection maybe can’t be done until data are copied to CPU memory • Some impossibe for saving all triggered data

  39. Conculsions • By using FADC we can observe exactly both long and haft life in Bi Po source that is limited by NIM & CAMAC • In fact, FADC is the most future choice due to many advantages as presented above

  40. My empression in this training at osaka university: • First of all I want to say your country is very beatiful and the people is very kindly • Secondly, the background from this training is very useful for me when I come back to Viet Nam and I hope to have another chance to come back here for cooporation with you in near fultuer University of Natural Sciences Faculty of Physics Department of Nuclear Physics 227 Nguyen Van Cu Street, 5 Dictrict, Ho Chi Minh City, VietNam www.hcmuns.edu.vn Le Cong Hao Email:lchao@phys.hcmuns.edu.vn

  41. Thanks to • Prof. Nomachi, Prof. Kishimoto, Prof. Kuno whom are organizers • Dr. Vo Hong Hai • Mr Kouno • Mr kanamaru • Mr Otake

  42. Acknowledgments • Osaka University • Prof. Nomachi Group • JICA • Professors give the lectures • My partners in doing BiPo decay

  43. Thanks for your attention! The end

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