Utilization of prompt gamma rays in gamma irradiation experiments

AbstractWell-sampled optical lightcurves of 146 gamma-ray bursts (GRBs) are compiled from literature. We identify possible emission components based on our empirical fits and present statistical analysis for these components. We find that the flares are related to prompt emission, suggesting that they could have the same origin in different episodes. The shallow decay segment is not correlated with prompt gamma-rays. It likely signals a long-lasting injected wind from GRB central engines. Early after onset peak is closely related with prompt emission. The ambient medium density profile is likely n ∝ r−1. No correlation between the late re-brightening bump and prompt gamma-rays or the onset bump is found. They may be from another jet component.

Download Full-text

Comment on ‘Imaging of prompt gamma rays emitted during delivery of clinical proton beams with a Compton camera: feasibility studies for range verification’

Physics in Medicine and Biology ◽

10.1088/1361-6560/61/24/8941 ◽

2016 ◽

Vol 61 (24) ◽

pp. 8941-8944

Author(s):

Arkadiusz Sitek

Keyword(s):

Gamma Rays ◽

Feasibility Studies ◽

Prompt Gamma ◽

Compton Camera ◽

Proton Beams ◽

Range Verification

Download Full-text

Improving the performance of 241Am-Be for PGNAA applications using a proper shielding for neutron source and the NaI detector

Nuclear Technology and Radiation Protection ◽

10.2298/ntrp1003205p ◽

2010 ◽

Vol 25 (3) ◽

pp. 205-211 ◽

Cited By ~ 1

Author(s):

Hamed Panjeh ◽

Hashem Hakimabad ◽

Lalle Motavalli

Keyword(s):

Gamma Rays ◽

Energy Region ◽

Gamma Ray ◽

Region Of Interest ◽

High Rate ◽

Prompt Gamma ◽

Peak Resolution ◽

Set Up ◽

Gamma Ray Detector

The gamma ray spectrum resolution from a 241Am-Be source-based prompt gamma ray activation analysis set-up has been observed to increase in the energy region of interest with enclosing the NaI detector in a proper neutron and gamma ray shield. We have investigated the tact that the peak resolution of prompt gamma rays in the region of interest from the set-up depends on the source activity to the great extent, size and kind of the detector and the geometry of the detector shield. In order to see the role of a detector shield, five kinds of the detector shield were used and finally the proper kind was introduced. Since the detector shield has an important contribution in the reduction of the undesirable and high rate gamma rays coming to the gamma ray detector, a good design of a proper shield enables the elimination of the unwanted events, such as a pulse pile-up. By improving the shielding design, discrete and distinguishable photoelectric peaks in the energy region of interest have been observed in the spectrum of prompt gamma rays.

Download Full-text

Chronic Gamma Irradiation Changes Phenotype and Gene Expression Partially Transmitted to Next-Generation Tomato Seedlings

Agronomy ◽

10.3390/agronomy11081638 ◽

2021 ◽

Vol 11 (8) ◽

pp. 1638

Author(s):

Seong-Min Kim ◽

Yeong Deuk Jo ◽

Jae-In Chun ◽

Jin-Baek Kim ◽

Jin-Ho Kang

Keyword(s):

Gene Expression ◽

Gamma Irradiation ◽

Gamma Rays ◽

Mutation Breeding ◽

Fruit Shape ◽

Leaf Length ◽

Trichome Density ◽

Next Generation ◽

Seed Number ◽

And Control

Compared to the studies on acute irradiation of seeds, fewer studies have reported on the chronic irradiation of seedlings, especially in fruit-bearing vegetables. We examined the effects of chronic gamma irradiation on tomato (Solanum lycopersicum ‘Micro-Tom’) seedlings exposed to gamma rays (50, 100, 150, and 200 Gy) for 4 weeks. As the total dose of gamma rays increased, leaf length, trichome density, and seed number were reduced in the irradiated seedlings (M1). Additionally, a change in fruit shape was observed. Chronic gamma irradiation reduced the expression of two trichome-related genes and affected the expression levels of 11 reactive oxygen species (ROS)-related genes. We examined the transmittance of these effects using M2 plants. The trichome density and fruit shape were similar between M2 and control plants; however, a reduction in leaf length and seed number was detected in M2 plants. Interestingly, changes in the expression of four ROS-related genes (ZAT10, Mn-SOD, POD3, and RBOH1) found in M1 were detected in M2 plants. Thus, the changes in phenotype and gene expression induced by chronic gamma irradiation were transmitted to the next generation. Additionally, we found novel mutants from M2 plants, suggesting that chronic gamma irradiation may be considered in tomato mutation breeding.

Download Full-text

Study on the immuno stimulation of radiation degraded β-glucan in swiss mice

Nuclear Science and Technology ◽

10.53747/jnst.v5i4.201 ◽

2015 ◽

Vol 5 (4) ◽

pp. 9-15

Author(s):

Thanh Long Nguyen ◽

Quang Luan Le

Keyword(s):

Cell Wall ◽

Immune System ◽

Gamma Irradiation ◽

Gamma Rays ◽

Irradiation Dose ◽

Functional Foods ◽

Water Soluble ◽

Molecular Weights ◽

Swiss Mice ◽

Stimulation Of

The mixtures β-glucan extracted from the yeast cell wall were irradiated under gamma rays from a Co-60 source at doses of 100, 200 and 300 kGy in order to prepare water-soluble β-glucan. Yields of the water soluble β-glucan produced are 25.9, 49.1, 66.71%, and their molecular weights (Mw) are 30.5, 24.9 and 10.8 kDa, respectively. There are no any new peak in the IR spectra of the irradiated β-glucan samples, but the intensity ratio between the peaks at wavenumber of 1156 cm-1 (assigned to C-O-C bond) and of 1040 cm-1 (assigned to C-C bond) in glycosidic linkages was reduced with irradiation dose. These results revealed that gamma irradiation did not cause any change in the β-glucan structure except the scissions of glycosidic linkages. In this study, immuno stimulation of the irradiated b-glucan was also investigated for the Swiss mice. After 28 days supplying with the irradiated b-glucan, not only cellular indexes (white blood cell, neutrophils and lymphocytes counts), but also humoral immunity indexes (IgA and IgM) of the mice significantly increased and the highest effects was obtained for the mice supplied with the oligoβ-glucan prepared by gamma irradiation at 200 kGy. Thus, the water soluble oligoβ-glucan with Mw ~ 24.9 kDa prepared by gamma radiation much stimulated the natural immune system (non-specific immunity) in mice including both the cellular and humoral immunities. Particularly, the irradiated b-glucan is a very promising product for preparation of functional foods aiming at cancer prevention.

Download Full-text