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Rehman, Haseeb ur,Lee, Jiyoung,Kim, Yonghee Elsevier 2017 Annals of nuclear energy Vol.105 No.-
<P><B>Abstract</B></P> <P>The laser-Compton scattering (LCS) phenomenon is one known method for producing energetic and high-intensity gamma rays with variable photon spectrums. Availability of high-intensity gamma rays has made probing the (γ,n)-based photonuclear transmutation possible and worth consideration. Parametric studies of LCS have shown that the gamma ray’s spectrum is tunable and dependent upon various facility-related parameters. In this paper, a systematic optimization study of the LCS spectrum has been performed in view of the incident laser energy, electron beam energy and collimation angle. This optimization has been done with the aim to maximize the transmutation reaction rates of long-living fission products (LLFPs) such as <SUP>129</SUP>I, <SUP>135</SUP>Cs, and <SUP>137</SUP>Cs that have an isotopic composition of typical LWR spent fuel. In addition, the (γ,n) and (γ,2n)-reaction rates have been simultaneously calculated in order to evaluate the feasibility of photonuclear transmutation using the (γ,n)-reaction. It has been shown that careful optimization of the LCS spectrum noticeably enhances the (γ,n)-reaction rate without requiring any isotopic separation of the iodine and cesium targets. Furthermore, in order to enhance the energy efficiency of the LCS-based photo-transmutation system, a novel multiple laser-Compton scattering extraction (MULEX) concept has been introduced in this work, and it has been shown that the total production of the LCS photons can easily be increased by a factor of 10 or 20 in a single accelerator system.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Presents a spectral optimization of LCS photons for the transmutation LLFPs. </LI> <LI> Calculation of the produced <SUP>135</SUP>Cs from <SUP>137</SUP>Cs considering ( γ , n ) and ( γ , 2 n ) reactions. </LI> <LI> A novel MULEX concept is presented to multiply LCS photons by a factor of 10 or more. </LI> </UL> </P>
A Feasibility Study on Photo-production of 99mTc with the Nuclear Resonance Fluorescence
주광호,이지영,Haseeb ur Rehman,김용희 한국원자력학회 2019 Nuclear Engineering and Technology Vol.51 No.1
This paper presents a feasibility study for producing the medical isotope 99mTc using the hazardous andcurrently wasted radioisotope 99Tc. This can be achieved with the nuclear resonance fluorescence (NRF)phenomenon, which has recently been made applicable due to high-intensity laser Compton scattering(LCS) photons. In this work, 21 NRF energy states of 99Tc have been identified as potential contributors tothe photo-production of 99mTc and their NRF cross-sections are evaluated by using the single particleestimate model and the ENSDF data library. The evaluated cross sections are scaled using known measurementdata for improved accuracy. The maximum LCS photon energy is adjusted in a way to cover allthe significant excited states that may contribute to 99mTc generation. An energy recovery LINAC systemis considered as the LCS photon source and the LCS gamma spectrum is optimized by adjusting theelectron energy to maximize 99mTc photo-production. The NRF reaction rate for 99mTc is first optimizedwithout considering the photon attenuations such as photo-atomic interactions and self-shielding due tothe NRF resonance itself. The change in energy spectrum and intensity due to the photo-atomic reactionshas been quantified using the MCNP6 code and then the NRF self-shielding effect was considered toobtain the spectrums that include all the attenuation factors. Simulations show that when a 99Tc target isirradiated at an intensity of the order 1017 g/s for 30 h, 2.01 Ci of 99mTc can be produced
Survivability Analysis of MANET Routing Protocols under DOS Attacks
( Sohail Abbas ),( Muhammad Haqdad ),( Muhammad Zahid Khan ),( Haseeb Ur Rehman ),( Ajab Khan ),( Atta Ur Rehman Khan ) 한국인터넷정보학회 2020 KSII Transactions on Internet and Information Syst Vol.14 No.9
The network capability to accomplish its functions in a timely fashion under failures and attacks is known as survivability. Ad hoc routing protocols have been studied and extended to various domains, such as Intelligent Transport Systems (ITSs), Unmanned Aerial Vehicles (UAVs), underwater acoustic networks, and Internet of Things (IoT) focusing on different aspects, such as security, QoS, energy. The existing solutions proposed in this domain incur substantial overhead and eventually become burden on the network, especially when there are fewer attacks or no attack at all. There is a need that the effectiveness of these routing protocols be analyzed in the presence of Denial of Service (DoS) attacks without any intrusion detection or prevention system. This will enable us to establish and identify the inherently stable routing protocols that are capable to survive longer in the presence of these attacks. This work presents a DoS attack case study to perform theoretical analysis of survivability on node and network level in the presence of DoS attacks. We evaluate the performance of reactive and proactive routing protocols and analyse their survivability. For experimentation, we use NS-2 simulator without detection or prevention capabilities. Results show that proactive protocols perform better in terms of throughput, overhead and packet drop.