A Fast and Universal Vlasov Solver for Beam Dynamics Simulations in 3D
The Vlasov equation can describe the evolution of a particle density under the effects of electromagnetic fields and thus it is possible to describe the evolution of a charged particle beam within an accelerator beam line. The Vlasov equation forms a partial differential equation in a 6D phase space witch renders it very expensive if it is solved via classical methods. A more efficient approach consists in representing the particle distribution function by a discrete set of characteristic moments. For each moment a time evolution equation can be stated. These ordinary differential equations can then be integrated efficiently by means of numerical methods if all acting forces together with a proper initial condition are given. The beam dynamics simulation tool V-Code has been implemented at TEMF on the basis of the moment approach. In this paper the numerical model, main features and designated use cases of the V-Code will be presented.
Further Development of the V-Code for Recirculating Linear Accelerator Simulations
The recirculating Superconducting Darmstadt Linear Accelerator S-DALINAC, installed at the institute for nuclear physics (IKP) at the TU Darmstadt, consists of a 10 MeV injector and a 40 MeV linac. Utilizing two recirculations, the linac can be used up to three times, leading to a maximum energy for nuclear physics experiments of 130 MeV. In this paper the further developments of the moment based simulation tool V-Code enabling it to simulate recirculating machines are presented along with simulation results of the first recirculation of the S-DALINAC.
Effects of thyrotropin-releasing hormone and a thyrotropin releasing hormone analog on growth and selected plasma hormones in lambs.
An 8-wk growth trial was conducted to assess the effects of continuous infusion of thyrotropin-releasing hormone (TRH) and an active TRH analog less than Aad-His-Pro-NH2 (the less than Aad is L-pyro-alpha-aminoadipic acid) on growth trial performance, carcass composition and hormone profiles of growing lambs. Both drugs were infused at 600 micrograms X lamb -1 X d -1 with 16 lambs/treatment. Both TRH and less than Aad-His-Pro-NH2 decreased average daily gain (ADG; P less than .01) and increased feed conversion (FC; P less than .01) compared with saline infused controls. Average daily feed intake was not altered. Carcasses of lambs given TRH or less than Aad-His-Pro-NH2 contained fewer kilograms of moisture (P less than .05) and appeared to contain fewer kilograms of protein. Thyrotropin-releasing hormone and less than Aad-His-Pro-NH2 increased thyroid gland weights (P less than .05), but pituitary gland weights were not different. Plasma thyrotropin (TSH) concentrations were increased by both drugs compared with control lambs, peaking at 4 to 7 d after initiating infusion. However, by 14 d, TSH concentrations returned to control levels. Triiodothyronine (T3) and thyroxine (T4) were elevated by both drugs over the entire 8-wk trial, with peak levels reached at 10 d and maintained for the duration of the study. Both TRH and less than Aad-His-Pro-NH2 increased prolactin over the entire period. Growth hormone levels were not altered by either drug. The effects of less than Aad-His-Pro-NH2 infusion on growth trial performance, carcass composition and hormone profiles of growing lambs were very similar to TRH. The negative effects of TRH and less than Aad-His-Pro-NH2 infusion on ADG, FC and carcass protein appear to be the result of elevated T3 and T4 levels.