High-power electron accelerator for the production of neutrons and radioisotopes

Purpose: To study the binary possibility of using the available linear electron accelerators for the neutron therapy and radioisotopes production. For both applications, calculations were performed and the results were normalized to the characteristics of the Mevex accelerator (average electron current 4 mA at a monoenergetic electron beam 35 MeV). It turns out that the production of both photoneutrons and radioisotopes is effective when using bremsstrahlung radiation generated in the giant dipole resonance of a heavy metal target. Material and methods: The unifying problem for both applications is the task of target cooling: at beam power ~ 140 kW, half of it or more is deposited directly in the target. Therefore the liquid heavy metal was selected as a target, in order to conjoin high thermohydraulics quality with maximal productivity both bremsstrahlung radiation and photoneutrons. The targets were optimized using precise codes for radiation transport and thermohydraulics problems. The optimization was also carried out for the installations as a whole: 1) for the composition of the material and configuration of the photoneutron extraction unit for neutron capture therapy (NCT) and 2) for the scheme of bremsstrahlung generation for radioisotopes production. Results: The photoneutron block provides an acceptable beam quality for NCT with a high neutron flux density at the output ~2·1010 cm–2s–1, which is an order of magnitude higher than the values at the output of the reactor beams that worked in the past and are currently being designed for neutron capture therapy. As for radioisotopes production, using optimal reaction channel (γ, n) 43 radioisotopes in 5 groups were received. For example, by the Mo100(γ,n)99Mo reaction the precursor 99Mo of main diagnostic nuclide 99mTc with specific activity ~6 Ci/g and total activity of the target 1.8 kCi could be produced after 1 day irradiation exposure. Conclusion: The proposed schemes of neutron and bremsstrahlung generation and extraction have a number of obvious advantages over traditional techniques: a) the applying of the electron accelerators for neutron production is much safer and cheaper than to use conventional reactor beams; b) accelerator with the target, the beam output unit with the necessary equipment and tooling can be placed on the territory of the clinic without any problems; c) the proposed target for NCT is liquid gallium, which also serves as a coolant; it is an “environmentally friendly” material, its activation is rather low and rapidly (in ~4 days) falls to the background level.

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High-Intensity Bremsstrahlung of Electron Accelerator in Photoneutron and Radioisotopes Production for Medicine

Medical Radiology and radiation safety ◽

10.12737/1024-6177-2019-64-5-42-47 ◽

2019 ◽

Vol 64 (5) ◽

pp. 42-47

Author(s):

Ю. Кураченко ◽

Yu. Kurachenko ◽

Е. Онищук ◽

E. Onischuk ◽

Е. Матусевич ◽

...

Keyword(s):

Heavy Metal ◽

Neutron Capture ◽

Specific Activity ◽

Radiation Transport ◽

Beam Quality ◽

Beam Power ◽

Liquid Gallium ◽

Neutron Capture Therapy ◽

Bremsstrahlung Radiation ◽

Electron Accelerators

Purpose: To study the binary possibility of using the available linear electron accelerators for the neutron therapy and radioisotopes production. For both applications, calculations were performed and the results were normalized to the characteristics of the Mevex accelerator (average electron current 4 mA at a monoenergetic electron beam 35 MeV). It turns out that the production of both photoneutrons and radioisotopes is effective when using bremsstrahlung radiation generated in the giant dipole resonance of a heavy metal target. Material and methods: The unifying problem for both applications is the task of target cooling: at beam power ~ 140 kW, half of it or more is deposited directly in the target. Therefore the liquid heavy metal was selected as a target, in order to conjoin high thermohydraulics quality with maximal productivity both bremsstrahlung radiation and photoneutrons. The targets were optimized using precise codes for radiation transport and thermohydraulics problems. The optimization was also carried out for the installations as a whole: 1) for the composition of the material and configuration of the photoneutron extraction unit for neutron capture therapy (NCT) and 2) for the scheme of bremsstrahlung generation for radioisotopes production. Results: The photoneutron block provides an acceptable beam quality for NCT with a high neutron flux density at the output ~2·1010 cm–2s–1, which is an order of magnitude higher than the values at the output of the reactor beams that worked in the past and are currently being designed for neutron capture therapy. As for radioisotopes production, using optimal reaction channel (γ, n) 43 radioisotopes in 5 groups were received. For example, by the Mo100(γ,n)99Mo reaction the precursor 99Mo of main diagnostic nuclide 99mTc with specific activity ~6 Ci/g and total activity of the target 1.8 kCi could be produced after 1 day irradiation exposure. Conclusion: The proposed schemes of neutron and bremsstrahlung generation and extraction have a number of obvious advantages over traditional techniques: a) the applying of the electron accelerators for neutron production is much safer and cheaper than to use conventional reactor beams; b) accelerator with the target, the beam output unit with the necessary equipment and tooling can be placed on the territory of the clinic without any problems; c) the proposed target for NCT is liquid gallium, which also serves as a coolant; it is an “environmentally friendly” material, its activation is rather low and rapidly (in ~4 days) falls to the background level.

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Optimized Growth and Laser Application of Yb:LuAG Single-Crystal Fibers by Micro-Pulling-Down Technique

Crystals ◽

10.3390/cryst11020078 ◽

2021 ◽

Vol 11 (2) ◽

pp. 78

Author(s):

Anye Wang ◽

Jian Zhang ◽

Shuai Ye ◽

Xiaofei Ma ◽

Baiyi Wu ◽

...

Keyword(s):

Single Crystal ◽

High Power ◽

Slope Efficiency ◽

Continuous Wave ◽

Beam Quality ◽

Axial Direction ◽

Optical Quality ◽

Central Wavelength ◽

High Power Lasers ◽

Crystal Fibers

Single-crystal fibers (SCFs) have a great application potential in high-power lasers due to their excellent performance. In this work, high-quality and crack-free Yb3+:Lu3Al5O12 (Yb:LuAG) SCFs were successfully fabricated by the micro-pulling-down (μ-PD) technology. Based on the laser micrometer and the X-ray Laue diffraction results, these Yb:LuAG SCFs have a less than 5% diameter fluctuation and good crystallinity along the axial direction. More importantly, the distribution of Yb ions is proved to be uniform by electron probe microanalysis (EPMA) and the scanning electron microscope (SEM). In the laser experiment, the continuous-wave (CW) output power using a 1 mm diameter Yb:LuAG single-crystal fiber is determined to be 1.96 W, at the central wavelength of 1047 nm, corresponding to a slope efficiency of 13.55%. Meanwhile, by applying a 3 mm diameter Yb:LuAG SCF, we obtain a 4.7 W CW laser output at 1049 nm with the slope efficiency of 22.17%. The beam quality factor M2 is less than 1.1 in both conditions, indicating a good optical quality of the grown fiber. Our results show that the Yb:LuAG SCF is a potential solid-state laser gain medium for 1 μm high-power lasers.

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Coherent beam combining of high power broad-area laser diode array with near diffraction limited beam quality and high power conversion efficiency

Optics Express ◽

10.1364/oe.21.031218 ◽

2013 ◽

Vol 21 (25) ◽

pp. 31218 ◽

Cited By ~ 15

Author(s):

B. Liu ◽

Y. Braiman

Keyword(s):

Laser Diode ◽

High Power ◽

Beam Quality ◽

Power Conversion ◽

Coherent Beam ◽

Diode Array ◽

Broad Area ◽

High Power Conversion Efficiency ◽

Laser Diode Array ◽

Coherent Beam Combining

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Experimental Investigation of Limits to Slow Axis Beam Quality in High Power Broad Area Diode Lasers

10.1109/islc.2014.229 ◽

2014 ◽

Author(s):

M. Winterfeldt ◽

P. Crump ◽

H. Wenzel ◽

G. Erbert ◽

G. Trankle

Keyword(s):

Experimental Investigation ◽

High Power ◽

Beam Quality ◽

Diode Lasers ◽

Broad Area ◽

Slow Axis

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Four factors describing of the beam quality of high-power lasers

10.1117/12.611222 ◽

2005 ◽

Author(s):

Xiangwan Du

Keyword(s):

High Power ◽

Beam Quality ◽

High Power Lasers

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Improving the beam quality of high-power laser diodes by introducing lateral periodicity into waveguides

10.1117/12.2010664 ◽

2013 ◽

Cited By ~ 2

Author(s):

Grzegorz Sobczak ◽

Elżbieta Dąbrowska ◽

Marian Teodorczyk ◽

Joanna Kalbarczyk ◽

Andrzej Maląg

Keyword(s):

High Power ◽

Beam Quality ◽

Laser Diodes ◽

High Power Laser ◽

Power Laser

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Re-evaluation of the interaction of malonyl-CoA with the rat liver mitochondrial carnitine palmitoyltransferase system by using purified outer membranes

Biochemical Journal ◽

10.1042/bj2670085 ◽

1990 ◽

Vol 267 (1) ◽

pp. 85-90 ◽

Cited By ~ 32

Author(s):

M P Kolodziej ◽

V A Zammit

Keyword(s):

Rat Liver ◽

Specific Activity ◽

Liver Mitochondria ◽

Subsequent Treatment ◽

Carnitine Palmitoyltransferase ◽

Rat Liver Mitochondria ◽

Outer Membranes ◽

High Affinity ◽

Malonyl Coa ◽

Order Of Magnitude

1. The interaction of malonyl-CoA with the outer carnitine palmitoyltransferase (CPT) system of rat liver mitochondria was re-evaluated by using preparations of highly purified outer membranes, in the light of observations that other subcellular structures that normally contaminate crude mitochondrial preparations also contain malonyl-CoA-sensitive CPT activity. 2. In outer-membrane preparations, which were purified about 200-fold with respect to the inner-membrane-matrix fraction, malonyl-CoA binding was largely accounted for by a single high-affinity component (KD = 0.03 microM), in contrast with the dual site (low- and high-affinity) previously found with intact mitochondria. 3. There was no evidence that the decreased sensitivity of CPT to malonyl-CoA inhibition observed in outer membranes obtained from 48 h-starved rats (compared with those from fed animals) was due to a decreased ratio of malonyl-CoA binding to CPT catalytic moieties. Thus CPT specific activity and maximal high-affinity [14C]malonyl-CoA binding (expressed per mg of protein) were increased 2.2- and 2.0-fold respectively in outer membranes from 48 h-starved rats. 4. Palmitoyl-CoA at a concentration that was saturating for CPT activity (5 microM) decreased the affinity of malonyl-CoA binding by an order of magnitude, but did not alter the maximal binding of [14C]malonyl-CoA. 5. Preincubation of membranes with either tetradecylglycidyl-CoA or 2-bromopalmitoyl-CoA plus carnitine resulted in marked (greater than 80%) inhibition of high-affinity binding, concurrently with greater than 95% inhibition of CPT activity. These treatments also unmasked an effect of subsequent treatment with palmitoyl-CoA to increase low-affinity [14C]malonyl-CoA binding. 6. These data are discussed in relation to the possible mechanism of interaction between the malonyl-CoA-binding site and the active site of the enzyme.

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