Symposium on Positron Emission Tomography and Boron Neutron Capture Therapy Time-Over-Threshold Calibration in J-PET

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The 3rd Symposium on Positron Emission Tomography and 1st Symposium on Boron Neutron Capture Therapy focused on Time-Over-Threshold calibration within the framework of J-PET. The event outlined experimental details, event selection, results, and key features of the Jagiellonian Positron Emission Tomograph. Methodology included measuring TOT values and accessing hit positions of primary and scattered photons to determine energy and scattering angles. Experimental details involved a small chamber with XAD4 and 22Na, with run specifications for analysis. Events selection criteria emphasized studying photon scattering using hit events.

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3rd Symposium on Positron Emission Tomography and 1st Symposium on Boron Neutron Capture Therapy Time Over Threshold calibration in the framework of J-PET Sushil K. Sharma on behalf of the J-PET collaboration Sushil K. Sharma 11/09/2018

Outline Introduction Experimental details Event s selection Results Summary & Outlook 3rd Jagiellonian Symposium on Positron Emission Tomography Sushil K. Sharma 11/09/2018

Jagiellonian - Positron Emission Tomograph 2-D front view J-PET .7cm 50 cm 192 plastic Scintillators 57.5 cm 46.75 cm Arranged axially in 3 layers 42.5 cm Key features : Trigger less DAQ TOT as measure of energy deposition 3rd Jagiellonian Symposium on Positron Emission Tomography Sushil K. Sharma 11/09/2018

Time-Over-Threshold & Energy deposition PMT A PMT B V V Thresholds Thresholds 1 1 1 1 TOT11 TOT11 2 2 2 2 TOT22 TOT22 3 3 3 3 TOT33 TOT33 4 4 4 4 TOT44 t t Signals from each photomultiplier are probed at four thresholds. TOT = TOTsumA + TOTsumB 3rd Jagiellonian Symposium on Positron Emission Tomography Sushil K. Sharma 11/09/2018

Methodology : What we have : Measured TOT values Hit positions of primary and scattered photon gives access to the values What is required : Energy of the incident photon True scattering angle Edep = f(Einc , ) 3rd Jagiellonian Symposium on Positron Emission Tomography Sushil K. Sharma 11/09/2018

Experimental details Small chamber in the center XAD4 22Na 3rd Jagiellonian Symposium on Positron Emission Tomography Sushil K. Sharma 11/09/2018

Experimental details Small chamber in the center XAD4 22Na Run specifications : Run number : 4 with small chamber Total files analysed : 500 / 3500 Velocity calibration : Applied Time Calibration : Applied 3rd Jagiellonian Symposium on Positron Emission Tomography Sushil K. Sharma 11/09/2018

Events selection - Analyzed : 3 Hit Events In order to study scattering of a photon, two hits are sufficient. 3rd Hit allows to use additional constraints to conjecture and tag the photon of different energy/origin Case 2 Case 1 e+ - e- annihilation into two photons (511 keV) high energetic photons 1274.6keV (Prompt) 3rd Jagiellonian Symposium on Positron Emission Tomography Sushil K. Sharma 11/09/2018

3 Hit Events ( Tagging 511 keV) (hits are ordered in time) Two hits are Back-to-Back gamma 3RD Hit from the scattering of gamma either after Hit 1 or Hit2 3rd Jagiellonian Symposium on Positron Emission Tomography Sushil K. Sharma 11/09/2018

3 Hit Events ( Tagging 1274.6 keV) (hits are ordered in time) Case 2: for 1274.6keV (Prompt) Ist Hit is prompt gamma 2nd Hit from the scattering of prompt gamma 3rd hit is assumed as one of the annihillation gamma from oPs decay as the time difference b/w Ist hit and 3rd hit is taken more than 10 ns 3rd Jagiellonian Symposium on Positron Emission Tomography Sushil K. Sharma 11/09/2018

3 Hit Angles 12< 23< 31 Diff. of two small. angles [ deg ] Sum of two small. angles [ deg ] 3rd Jagiellonian Symposium on Positron Emission Tomography Sushil K. Sharma 11/09/2018

Tagging the 511 keV photon Applied Cuts: 1 2 Hit 1 and Hi 2 are back to back (511keV) TOT : TOThit1<30 ns TOThit2<30 ns Hit 1 Hit 2 Hit 3 3 Along Z : Z -23<Zhit1<23 -23<Zhit2<23 -23<Zhit3<23 .7cm 4 NO 2 hits in same scintillator 3rd Jagiellonian Symposium on Positron Emission Tomography Sushil K. Sharma 11/09/2018

Tagging the 1274.6 keV photon Cut on 3 Hits angles Along Z : for all hits -23 < Z < 23 Hit 1 Hit 2 Hit 3 TOThit1 < 65 ns Time diff: Timehit3 Timehit1 > 10 ns NO 2 hits in same scintillator 3rd Jagiellonian Symposium on Positron Emission Tomography Sushil K. Sharma 11/09/2018

Results Scattering angle distribution (511 keV) For the assignment of scattered hit to its origin, scatter test(S) was applied: S= (timescatter timeorigin) Distancescatter-origin / c 511 keV 511 keV Selected scattered angles ( ) 3rd Jagiellonian Symposium on Positron Emission Tomography Sushil K. Sharma 11/09/2018

Results Scattering angle distribution (1274.6 keV) Selected scattering angles ( ) 3rd Jagiellonian Symposium on Positron Emission Tomography Sushil K. Sharma 11/09/2018

Results : Summed over 511 keV and 1274.6 keV TOT spectra Scattered angless ( ) 3rd Jagiellonian Symposium on Positron Emission Tomography Sushil K. Sharma 11/09/2018

Results : TOT vs Edep Only for 511 keV Only for 1274.6 keV Relationship between TOT and Edep individual for 511 keV and 1274.6 keV photons 3rd Jagiellonian Symposium on Positron Emission Tomography Sushil K. Sharma 11/09/2018

Results : TOT vs Edep There is an enhancement in the value of TOT with the increase in the energy deposi- tion. However, There contribution visible during the selection of prompt gamma ??? is an additional Relationship between TOT and Edep for 511 keV and 1274.6 keV photons together 3rd Jagiellonian Symposium on Positron Emission Tomography Sushil K. Sharma 11/09/2018

Results : TOT vs Edep Energy bins [ 500, 550 ] 3rd Jagiellonian Symposium on Positron Emission Tomography Sushil K. Sharma 11/09/2018

Results : TOT vs Edep Fitting of the TOT projections for most populated energy depositions : 3rd Jagiellonian Symposium on Positron Emission Tomography Sushil K. Sharma 11/09/2018

Results : TOT vs Edep 3rd Jagiellonian Symposium on Positron Emission Tomography Sushil K. Sharma 11/09/2018

Results : TOT vs Edep Additional contribution visible during the selection of prompt gamma ??? Investigation procedure : For the calculated scattering angles ( ) for 1275 photon a). Estimate the Edep: Edep1 = f( 511 keV , ) Edep2 = f( 1275 keV, ) b) cal. TOT value for Edep1 using TOT = A + B *ln(Edep1) c). Fill the hist(Edep2, TOT) 3rd Jagiellonian Symposium on Positron Emission Tomography Sushil K. Sharma 11/09/2018

Results : TOT vs Edep Black line shows the histogram filled with the discussed algorithem. Assuming the contribution might be from 511 keV photon, FIT THE UNKNOWN REGION. 3rd Jagiellonian Symposium on Positron Emission Tomography Sushil K. Sharma 11/09/2018

TOT vs Edep ( for different hit Z position) Z (50 cm) - 2 3 - 1 0 . 5 - 1 7 . 5 - 3 . 5 3 . 5 1 0 . 5 1 7 . 5 2 3 .7cm 3rd Jagiellonian Symposium on Positron Emission Tomography Sushil K. Sharma 11/09/2018

TOT vs Edep ( for different hit Z position) 50000 40000 30000 TOT [ ps ] -23 to -17.5 cm -17.5 to -10.5 cm -10.5 to -3.5 cm -3.5 to 3.5 cm 3.5 to 10.5 cm 10.5 to 17.5 cm 17.5 to 23 cm 20000 10000 0 200 400 Energy Deposition [ keV ] 600 800 1000 3rd Jagiellonian Symposium on Positron Emission Tomography Sushil K. Sharma 11/09/2018

Summary & Outlook An algorithm is developed to tag the photons of different energy and their scattering distributions are studied. Preliminary relationship between energy deposition by interacting photon and the corresponding TOT values is established. TOT vs Edep relationship has Z dependence which is currently being investigated. 3rd Jagiellonian Symposium on Positron Emission Tomography Sushil K. Sharma 11/09/2018

3rd Jagiellonian Symposium on Positron Emission Tomography Sushil K. Sharma 11/09/2018

Back-up slides 3rd Jagiellonian Symposium on Positron Emission Tomography Sushil K. Sharma 11/09/2018

Results TOT spectra 3 Hits Hit 1 Hit 2 Hit 3 3rd Jagiellonian Symposium on Positron Emission Tomography Sushil K. Sharma 11/09/2018

Summary & Outlook 200 keV 230 keV 270 keV 310 keV 380 keV 520 keV 640 keV 730 keV 790 keV 870 keV 950 keV 40000 Time Over Thresholds [ ps ] 30000 For different z-intervals , the center was chosen. 20000 10000 0 -20 -10 0 10 20 Z [ cm ] 3rd Jagiellonian Symposium on Positron Emission Tomography Sushil K. Sharma 11/09/2018

Summary & Outlook 3rd Jagiellonian Symposium on Positron Emission Tomography Sushil K. Sharma 11/09/2018

Summary & Outlook Threshold 1 Threshold 2 Threshold 3 Threshold 4 3rd Jagiellonian Symposium on Positron Emission Tomography Sushil K. Sharma 11/09/2018