67 Cu Production in Gallium Cu Production in Gallium 67 George Kharashvili Radiation Physics, RadCon 4/14/17
Previous Test of 67 Cu Production in Ga • 4D beamline • Beam test plan described in ATLis 16434 • RWP #2016-J004 • Ga and Zn targets • 56 MeV, 89 nA, 5 min • Samples replaced – No notable radiological concerns • 18.5 MeV, 2.5 µA, 1 h • 1 R/h on contact dose rate minutes after irradiation • Samples removed 20 hours after the irradiation • Tungsten radiator was the most radioactive item • Did not create notable radiological concernes, stored for decay
Results of the Previous Test Measured 67 Cu FLUKA 67 Cu Ratio Target Yield [Bq/W-h] Yield [Bq/W-h] FLUKA/Meas. Ga 111 ± 18 228 ± 7 2.05 ± 0.33 Zn 103 ± 17 75.7 ± 3.3 0.73 ± 0.12 • Possible reasons causing the Possible reasons causing the discrepancies: discrepancies: – Imperfect target alignment Imperfect target alignment – How well the beam energy and the beam How well the beam energy and the beam energy spread were known energy spread were known – Issues with the model Issues with the model
New Experiment New Experiment • Produce enough Produce enough 67 67 Cu for Cu for radiochemical separation radiochemical separation – 100s 100s of µ of µCi Ci • Measure radiochemical separation Measure radiochemical separation efficiency at VCU efficiency at VCU • Provide additional/more reliable Provide additional/more reliable data point for validating the data point for validating the FLUKA and TALYS models FLUKA and TALYS models
Irradiation Parameters Irradiation Parameters • E e- = 18.5 to 18.65 MeV = 18.5 to 18.65 MeV – Avoid incident photons above 18.59 MeV Avoid incident photons above 18.59 MeV in in Ga Ga ( ( 67 67 Ga production threshold, Ga production threshold, interfears interfears with measurement) with measurement) • Energy spread: Energy spread: σ E = 50 = 50 keV keV • Beam power: P = 1 kW Beam power: P = 1 kW • Beam size: Beam size: σ = 2.5 mm = 2.5 mm • Irradiation time Irradiation time – Minimum: 48 hours Minimum: 48 hours – 42% of 42% of A saturation saturation – Optimal: > 72 hours Optimal: > 72 hours – 55% of 55% of A saturation saturation • Radiator Radiator 1 mm W 1 mm W • Target Target 85 g natural gallium in 85 g natural gallium in hBN hBN capsule capsule
Setup model hBN Capsule Ga Target Be Window W radiator
Prompt Radiation Field Prompt Radiation Field • 3/10/14 4D spectrometer dump shielding 3/10/14 4D spectrometer dump shielding commissioning test commissioning test – ATLis ATLis 13446 13446 – Surveys during 123 MeV, 100 µA Surveys during 123 MeV, 100 µA – 5 µrem/h of neutron dose rate and 80 µrem/h 5 µrem/h of neutron dose rate and 80 µrem/h photon dose rate were measured in north photon dose rate were measured in north access building access building – Radiological conditions were found acceptable Radiological conditions were found acceptable – Neutron source term Neutron source term 85 ± 3 rem/h at 1m from the dump 85 ± 3 rem/h at 1m from the dump • 18.5 MeV test will produce the same neutron 18.5 MeV test will produce the same neutron sourceterm sourceterm if beam power equals if beam power equals 1.1 kW 1.1 kW • Additional shielding not required Additional shielding not required
Experimental Procedure 1. Remove W radiator 2. Position poly block (“dummy target”) with radiochromic film on both ends 3. Close side cooling plates 4. Beam permit 5. Tune beam for 5 minutes – Observe with camera 6. Controlled access 7. Check position / align / repeat if necessary 8. Install W radiator 9. Beam Permit 10. Run CW for 48 to 72 hours
Power Deposition per kW of Beam Part Power [W] Be Window 6 W Radiator 280 hBN Capsule 355 Ga Target 233 Cu Cooling 27 Total 901
Induced Radioactivity Induced Radioactivity Expected 67 Cu activities in Ga, 1 day after the irradiation Beam Energy 18.5 MeV 18.65 MeV Irradiation Time 380 µCi Ci 465 µCi Ci 48 h 510 µCi Ci 620 µCi Ci 72 h
Post-Irradiation Dose Rates Post-Irradiation Dose Rates Dose Rates [mrem/h] at 30 cm for E=18.6 MeV Decay time [h] 1 12 24 Full setup 3050 190 100 Target only � 1770 6.2 2.4 (hBN capsule + Ga)
Recommend
More recommend
