ENGINEERING OF THE LOW-ENERGY BEAM TRANSPORT LINE IN THE Не⁺ IONS LINAC

The design of a low-energy beam transport line in the helium ions linear accelerator is proposed. For experiments with the low-energy helium ions the vacuum chamber in a transport line is in addition included for an irradiation of investigated materials. The mathematical modeling method investigates coordination variants of an injector beam output emittance with an accelerating structure acceptance with use of electromagnetic quadrupole lenses, electrostatic lenses and the focusing solenoid. It is shown that the optimal variant, ad hoc, is the focusing solenoid application. The calculated value of a current of the helium accelerated ions makes 4.5 mА.

An Active Plasma Beam Dump for EuPRAXIA Beams

Plasma wakefields driven by high power lasers or relativistic particle beams can be orders of magnitude larger than the fields produced in conventional accelerating structures. Since the plasma wakefield is composed not only of accelerating but also of decelerating phases, this paper proposes to utilize the strong decelerating field induced by a laser pulse in the plasma to absorb the beam energy, in a scheme known as the active plasma beam dump. The design of this active plasma beam dump has considered the beam output by the EuPRAXIA facility. Analytical estimates were obtained, and compared with particle-in-cell simulations. The obtained results indicate that this active plasma beam dump can contribute for more compact, safer, and greener accelerators in the near future.

VERIFICATION OF THE DETERMINATION OF 12 MEV ELECTRON BEAM OUTPUT VERSA HD / 154714 LINEAR SPEEDING PLANE IN MAYAPADA HOSPITAL

VERIFICATION OF THE DETERMINATION OF THE NOMINAL ENERGY BEAM OUTPUT OF THE 12 MEV LINEAR ACCELERATOR PLANE ELEKTA VERSA HD / 154714 AT MAYAPADA HOSPITAL. This paper describes verifying the determination of the 12 MeV nominal energy beam electron water absorption dose emitted from the Elekta Versa HD / 154714 medical linear accelerator owned by Mayapada Hospital, Lebak Bulus, Jakarta. Measurements were done in the 1D water phantom Scanner under reference conditions with the distance of the radiation source to the surface of the water 100 cm and the radiation field formed by the applicator 10 cm x 10 cm and the depth corresponding to (0.6 R50 - 0.1) cm. The IBA CC13 ionization detector is used as a radiation measurement tool for PDD measurements, while the Roos parallel ionization detector is used for absolute measurements. Roos's parallel ionizer detector is aligned with PTKMR-BATAN's PTW Webline electrometer. This detector is also traced to the primary standard laboratory of BIPM, France. Meanwhile, the PCC04 chip ionizing detector parallel to the PCC04 is coupled with a Dose 1 electrometer owned by Mayapada Hospital, which is traced to the PTB primary standard laboratory. Calculation of measurement results is carried out using the IAEA dosimetry protocol contained in Technical Report Series No. 398. The results obtained indicate a fairly good fit between the two measurements with a difference of 0.3%

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

The purpose of the work is to study the possible use of existing high-power electron accelerators for neutron therapy and the production of radioisotopes. Calculations were performed for both applications and the results were normalized to the characteristics of the existing MEVEX accelerator (average electron current 4 mA at a monoenergetic electron beam of 35 MeV). A unifying problem for the applications is the task of cooling the target: at a beam energy of about 140 kW, almost half of this energy is released directly in the target. For this reason, a liquid heavy metal was chosen as a target in order to combine the high quality of thermohydraulics with the maximum performance of both bremsstrahlung radiation and photoneutrons. The targets were optimized using precision codes for radiation transfer and thermal-hydraulic applications. Optimization was also carried out on the installation as a whole: (1) on the composition of the material and the configuration of the photoneutron extraction unit for neutron capture therapy (NCT) and (2) on the bremsstrahlung generation scheme for producing radioisotopes. The photoneutron unit provides an acceptable beam quality for NCT with a large neutron flux density at the output: ~ 2·1010 cm–2s–1, which is an order of magnitude higher than the output values of existing and planned reactor beams. Such intensity at the beam output will make it possible in many cases to abandon fractionated irradiation. As for the production of radioisotopes, in the calculations for the (γ, n) reaction, 43 radionuclides in five groups were obtained. For example, using the Mo100(γ, n)99Mo reaction, it is possible to obtain the 99Mo precursor of the main diagnostic isotope 99mTc with a specific activity of ~ 6 Ci/g and a total target activity of 1.8 kCi after irradiation for 24 hours. The proposed schemes for generating and outputting photoneutrons and bremsstrahlung have a number of obvious advantages over traditional methods, including: (a) the use of electron accelerators for producing neutrons is much safer and cheaper than the use of reactor beams; (b) the accelerator with the target and the beam extraction unit with the necessary equipment and tooling can be easily placed in a clinical setting; and (c) the proposed liquid gallium target for NCT, which also serves as a coolant, is an “environmentally friendly” material: its activation is relatively small and drops quickly (after about four days) to the background level.

Quality Assurance of External Beam Radiotherapy and Results of Participation in IAEA/WHO TLD Inter-comparison program for Radiotherapy Level Dosimetry at Khwaja Yunus Ali Medical College & Hospital in Bangladesh

Background: The outcome of the radiotherapy is highly dependent on how precisely dose is delivered to the tumor and should not exceed±5% of the prescribed dose including all types of uncertainties involved in the treatment procedure. Objectives: This manuscript describes the comprehensive Quality Assurance (QA) program for two linear accelerators by ensuring Percentage Depth Dose (PDD), Quality Index (QI), Beam Flatness and Symmetry, and beam output consistency at Khwaja Yunus Ali Medical College and Hospital, Sirajganj, Bangladesh. The program is designed according to the policy of the center and by the guidelines of Bangladesh Atomic Energy Regulatory Authority. Materials and Methods: The adopted QA procedure at our center included daily, weekly, monthly, and yearly checks, as well as individual treatment verifications and participation in IAEA/WHO TLD inter-comparison Program. Results: The results of the study showed reproducibility in all QA procedures with an average photon for monthly beam output 0.988±0.011, 0.989±0.010 and 1.005±0.006 for 4 MV, 6 MV and 15 MV respectively. The maximum variation of calibration factors of the chambers for last five years between the manufacturer values and the average calibration coefficient lies within -0.298 to 0.47% with an uncertainty of ±1.8% (k=1). The results of IAEA/WHO TLD inter-comparison program of dose measurement shows the ratio of IAEA to KYAMCH values was 1.009±0.018. Conclusion: The above result shows an excellent agreement of calibration coefficient of ionization chambers and dosimetry with the international standard system KYAMC Journal Vol. 10, No.-3, October 2019, Page 147-151