Abstrak – Cancer is a dangerous disease which is one of the main causes of death in the world, which is 8.8 million deaths in 2015. A new method has been developed for the treatment of cancer with small side effects, Boron Neutron Capture Therapy (BNCT). BNCT is based on the ability of non-radioactive isotopes Boron-10 to capture thermal neutrons. Boron is the main key of the BNCT process wherein, radiation of cancer cells can be carried out selectively if the cancer contains high concentrations of boron. Boron doses in cancer cells cannot be measured directly, therefore artificial network methods are used to compute doses computationally, namely the Monte Carlo method with the Particle and Heavy Ion Transport Code System (PHITS) program. Boron dose used was 10, 20 and 30 ?g/g. It was found that the greater the boron dose the greater the number of neutrons absorbed. The results showed that the largest absorption dose occurred in the Gross Tumor Volume (GTV) area of ??7.7076E-10 Gy/cm2. Key words: Cancer, BNCT, Dose of Boron, PHITS.

Synthesis and characterization of Ba1-xLaxFe12O19 based permanent magnet samples with variations in composition (x = 0; 0.02; 0.04; and 0.08) has been done. The method used is a solid state reaction. The phase formation of the sample Ba1-xLaxFe12O19 was carried out at 1200oC for 2 hours. The results of the X-ray diffraction pattern analysis show that all sample compositions have a single phase BaFe12O19. The results of magnetic properties testing using VSM showed that the best coercivity field and remanent magnetization values were obtained at the composition of x = 0.04. The effect of substitution of lanthanum into the barium atom can increase the number of magnetic domains which are indicated by the increase in the coercivity value of the material along with the increasing composition of x. It was concluded that the composition of Ba1-xLaxFe12O19 is a permanent magnet with the best product energy.

In this study, the substitution of elements Nd and Eu on the superconductor Y1-x-yNdxEuyBa2Cu4O8?? (Y-124) has been carried out using compounds Y2O3, BaCO3, CuO, Nd2O3 and Eu2O3 with molar variations of Nd (x) and Eu (y), respectively. 0, 0,05, 0,1, 0,15 and 0,2 respectively to determine the effect of Nd and Eu substitution on the volume fraction and crystal structure of the superconducting Y-124. Samples were synthesized using wet mixing method with HNO3 as solvent, followed by calcination process at 600 oC for 3 hours and sintering process at 900 oC for 10 hours. Analysis of the structure of the superconducting Y-124 was carried out by characterizing X-ray Diffraction (XRD) and Fourier-Transform Infrared Spectroscopy (FTIR). The results of XRD characterization showed a fine and sharp spectrum which indicated that crystallization had occurred completely. The resulting spectrum was dominated by the Y-124 phase and a small percentage of the impurities were detected. Substitution of Nd and Eu elements resulted in volume fractions of 82,7 %, 83,6 %, 84,4 %, 87,0 % and 85,9 %, respectively. The volume fraction value increased with the addition of Nd and Eu from 0 to 0,15, then decreased at 0,2. This indicates that the optimization of the addition of Nd and Eu is at a value of 0,15 in the molar ratio of compounds. The substitution of Nd and Eu elements also causes changes in the lattice parameters towards the a-axis with values between 3,7549 and 3,8323 , towards the b-axis with values between 3,8094 and 3,8425 , and towards the c-axis with values between 26,7390 and 26,8970. The FTIR results show the presence of an absorption band in the YBCO region, but the sample still contains impurities which are indicated to come from BaCO3 and HNO3.