Dosimetry of non-uniform activity distribution: possibility to use the local energy deposition approach at the voxel level in radionuclide therapy

When an electron beam is used to expose a resist, neighboring regions of the resist are also partially exposed. This arises from multiple scattering of the electrons in the resist and by backscattering of the electrons in both the resist and (mainly) in the substrate beneath the resist. From various studies1,2 this non-local energy deposition can be characterized by a number of regions, There is a very intense energy deposition, which is typically quite narrow and is produced by the direct incident beam broadened by multiple scattering in the resist. This is surrounded by an approximate plateau of intensity of about 1-2 orders of magnitude weaker, which is produced almost entirely by electrons backscattering from the substrate. The plateau arises from two conflicting effects: the backscattering yield drops as we move away from the central beam, but the mean electron energy also decreases. Therefore the stopping power increases, thus tending to offset the first effect. Finally this plateau cuts off fairly sharply at a distance approximately equal to the Bethe range of electrons in the substrate.

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Transonic flow control by means of local energy deposition

Technical Physics ◽

10.1134/s106378421111003x ◽

2011 ◽

Vol 56 (11) ◽

pp. 1552-1561 ◽

Cited By ~ 4

Author(s):

S. M. Aul’chenko ◽

V. P. Zamuraev ◽

A. P. Kalinina

Keyword(s):

Flow Control ◽

Transonic Flow ◽

Energy Deposition ◽

Local Energy

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Slow and sausage loop mode excitation due to local and global spontaneous perturbations

Astronomy and Astrophysics ◽

10.1051/0004-6361/202039023 ◽

2020 ◽

Vol 644 ◽

pp. A106

Author(s):

H. Capettini ◽

M. Cécere ◽

A. Costa ◽

G. Krause ◽

O. Reula

Keyword(s):

Energy Deposition ◽

Heating Time ◽

Local Energy ◽

Slow Mode ◽

Internal Loop ◽

Local Character ◽

Mode Pattern ◽

Mode Excitation ◽

Different Types ◽

Local Loop

Aims. We analyse the capability of different types of perturbations associated with usual environment energy fluctuations of the solar corona to excite slow and sausage modes in solar flaring loops. Methods. We performed numerical simulations of magnetohydrodynamic ideal equations with a consideration of straight plasma magnetic tubes subject to local and global energy depositions. Results. We find that local loop energy depositions of typical microflares [∼(1027 − 1030) erg] are prone to driving slow shock waves that induce slow-mode patterns. The slow-mode features are obtained for every tested local energy deposition inside the loop. Meanwhile, in order to obtain an observable sausage mode pattern, a global perturbation that is capable of instantaneously modifying the internal loop temperature is required; specifically, the characteristic conductive heating time must be much smaller than the radiative cooling one. Experiments carried out by varying the parameter β demonstrate that the excitation of sausage modes does not significantly depend on the value of this parameter but, rather, depends on the global or local character of the energy source.

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