Authors:Gary Perkins, Omar Khatib, Matthew Peterson, Annukka Kallinen, Tien Pham, Alison Ung, Ivan Greguric and Giancarlo Pascali
Carbon dioxide chemistry is an area of continuing growth in recent times, due to socioeconomic and environmental reasons. Several methods have now been reported for obtaining N-methylation on primary and secondary amines directly from CO2. We have translated in two microfluidic setups (Slug Flow [SF] and Tube-in-Tube [TiT]) a ruthenium (Ru)-catalyzed process previously reported using a pressure vessel. Here, we demonstrate how the SF approach is more efficient but requires more input to reach a steady state, while the TiT system is less efficient but more tuneable.We have tested these processes on three model amines and two radiopharmaceutical precursors that are routinely used in 11C chemistry. The microfluidic processes tested are also potentially more efficient than the pressure vessel counterpart, in terms of amount of Ru catalyst needed (1% vs. 10%) and projected reaction completion time.
Authors:Van Nguyen, Duc Pham, Tien Kim, Md. Rahman, Kyung-Sook Kim, Guinyun Kim, Hee-Seock Lee, Moo-Hyun Cho, In Ko, Won Namkung and Tae-Ik Ro
The isomeric yield ratios for the natFe(γ,xn1p)52m,gMn reactions have been measured by the activation and the γ-ray spectroscopic methods at 50-, 60-, 70-MeV, and 2.5-GeV bremsstrahlung
energies. The high purity natural iron foils in disc shape were irradiated with uncollimated bremsstrahlung beams of the Pohang
Accelerator Laboratory. The induced activities in the irradiated foils were measured by the high-resolution γ-ray spectrometry
with a calibrated high-purity Germanium (HPGe) detector. In order to improve the accuracy of the experimental results the
necessary corrections were made in the gamma activity measurements and data analysis. The obtained isomeric yield ratios for
the natFe(γ,xn1p)52m,gMn reactions at 50-, 60-, 70-MeV, and 2.5-GeV bremsstrahlung energies are 0.27 ± 0.03, 0.33 ± 0.04, 0.34 ± 0.04, and 1.25 ± 0.15,
respectively. The present results at 50-, 60-MeV, and 2.5-GeV bremsstrahlung energies are the first measurements. We found
that the isomeric yield ratio of the natFe(γ,xn1p)52m,gMn reaction depends on the incident bremsstrahlung energy and the mass difference between the product and the target nucleus
when we compared the present results with other experimental data at different energies.
Authors:Md. Rahman, Kyung-Sook Kim, Manwoo Lee, Guinyun Kim, Youngdo Oh, Hee-Seock Lee, Moo-Hyun Cho, In Ko, Won Namkung, Van Nguyen, Duc Pham, Tien Kim and Tae-Ik Ro
We measured isomeric-yield ratios for the 197Au(γ,n)196m,gAu reactions with bremsstrahlung energies of 50-, 60-, 70- MeV, and 2.5-GeV at the two different electron linac of the Pohang
accelerator laboratory by using the activation method. The photons were produced when a pulsed electron beam hit a thin tungsten
target. The well-known photoactivation method was used and hence the induced activities in the irradiated foils were measured
with the high-resolution γ-ray spectrometric system consisting of lithium drifted high-purity Germanium detector and a multichannel
analyzer. The measured isomeric-yield ratios for the 197Au(γ,n)196m,gAu reactions were (4.95 ± 0.51) × 10−4, (5.72 ± 0.72) × 10−4, (6.03 ± 0.50) × 10−4, and (9.27 ± 0.83) × 10−4 for 50-, 60-, 70-MeV, and 2.5-GeV bremsstrahlung energies, respectively. The present results measured with the bremsstrahlung
energy higher than 60-MeV are the first measurement.