Determination of atomic form factors by means of coherent bremsstrahlung

Tobiyama, M.; Endo, I.; Monaka, T.; Sumi, Y.; Uchida, H.; Yamamoto, Norimasa; Yoshida, Kunio; Watanabe, K.; Ohba, Takayoshi; K, Baba; Emura, T.

doi:10.1103/physrevb.44.9248

Cited by 10 publications

(5 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Uncertainties of the latter, connected with both the qualitative nature of the introduction of the boundary ε ⊥max of the diffusion approximation applicability region and the planar potential model, are displaced in table 1 for 400 GeV protons and (110) Si planes. As one can see, both the uncertainty of the boundary energy ε ⊥max definition and the transition between the potential models [22] and [21] change the l dech value by less then one percent. Considerably smaller dechanneling length, obtained with the Moliere potential [9], reflects the limited applicability of the latter to the channeling phenomenon.…”

Section: Diffusion Equation Boundary Conditionsmentioning

confidence: 99%

Quantitative theory of channeling particle diffusion in transverse energy in the presence of nuclear scattering and direct evaluation of dechanneling length

Tikhomirov

2017

Eur. Phys. J. C

View full text Add to dashboard Cite

A refined equation for channeling particle diffusion in transverse energy taking into consideration largeangle scattering by nuclei is suggested. This equation is reduced to the Sturm-Liouville problem, allowing one to reveal both the origin and the limitations of the dechanneling length notion. The values of the latter are evaluated for both positively and negatively charged particles of various energies. New features of the dechanneling dynamics of positively charged particles are also revealed. First, it is demonstrated that the dechanneling length notion is completely inapplicable for their nuclear dechanneling process. Second, the effective electron dechanneling length of positively charged particle varies more than twice converging to a constant asymptotic value only at the depth exceeding the latter.

show abstract

Section: Diffusion Equation Boundary Conditionsmentioning

confidence: 99%

Quantitative theory of channeling particle diffusion in transverse energy in the presence of nuclear scattering and direct evaluation of dechanneling length

Tikhomirov

2017

Eur. Phys. J. C

View full text Add to dashboard Cite

show abstract

“…As noted by Insana, 2 light scattering from lasers has been used to characterize the internal structure of glasses and polymers, 3 and x rays have been used to characterize the structure of atoms. 4 In acoustics, low-frequency sound waves ͑below 1 kHz͒ have been used to measure the size and distribution of turbulence in the atmosphere. 5 In a statistical sense, the frequency dependence of ultrasound backscatter can be used to extend the resolution of conventional B-mode imaging to tens of micrometers.…”

Section: Introductionmentioning

confidence: 99%

Characterization of tissue microstructure using ultrasonic backscatter: Theory and technique for optimization using a Gaussian form factor

Oelze

Zachary

O’Brien

2002

The Journal of the Acoustical Society of America

173

162

View full text Add to dashboard Cite

Characterization of tissue microstructure through ultrasonic backscatter is hypothesized to aid in detection and classification of diseased tissues. Radio frequency signals backscattered from tissues can be modeled according to the assumed shape, size, and distribution of scatterers in tissues. Power spectra of rf backscattered signals describe the frequency dependence of scatterers. Experimental measurements of ultrasonic backscatter from spontaneous mammary tumors in rats are obtained over the frequency range of 4 to 12 MHz. The power spectra measured from rat tumors are compared to theoretical power spectra derived from a 3D spatial autocorrelation function assuming a Gaussian distribution. Independent values of average scatterer diameter and acoustic concentration are obtained by approximating the measured power spectrum with a best-fit line. Enhanced B-mode images are made of the rat tumors and surrounding tissues with superimposed regions of interest quantified by estimated average scatterer sizes and acoustic concentrations. Scattering properties estimated inside the tumors and in surrounding tissues are shown to be distinct. Overall, estimates showed a 44.8% increase of average scatterer diameter inside the tumor as compared to tissues outside the tumor. With the exception of one rat, all estimates of the scatterers' average acoustic concentration inside the tumor were less than outside the tumors.

show abstract

“…Figure 3 shows beam profiles under either channeling or VR alignment (black curves) as compared with the predictions of Monte Carlo simulations (red curves). The code uses an inter-planar potential based on measured atomic form factors for Si [37] and solves the equation of motion for the electrons interacting with the crystal. The code does not take into account radiative losses since they are negligible because the crystal length is 3 × 10 −4 times the radiation length.…”

mentioning

confidence: 99%

Steering of a Sub-GeV Electron Beam through Planar Channeling Enhanced by Rechanneling

et al. 2014

View full text Add to dashboard Cite

We report the observation of efficient steering of a 855 MeV electron beam at MAMI (MAinzer MIkrotron) facilities by means of planar channeling and volume reflection in a bent silicon crystal. A 30.5 μm thick plate of (211) oriented Si was bent to cause quasimosaic deformation of the (111) crystallographic planes, which were used for coherent interaction with the electron beam. The experimental results are analogous to those recorded some years ago at energy higher than 100 GeV, which is the only comparable study to date. Monte Carlo simulations demonstrated that rechanneling plays a considerable role in a particle's dynamics and hinders the spoiling of channeled particles. These results allow a better understanding of the dynamics of electrons subject to coherent interactions in a bent silicon crystal in the sub-GeV energy range, which is relevant for realization of innovative x-ray sources based on channeling in periodically bent crystals.

show abstract

Determination of atomic form factors by means of coherent bremsstrahlung

Cited by 10 publications

References 15 publications

Quantitative theory of channeling particle diffusion in transverse energy in the presence of nuclear scattering and direct evaluation of dechanneling length

Quantitative theory of channeling particle diffusion in transverse energy in the presence of nuclear scattering and direct evaluation of dechanneling length

Characterization of tissue microstructure using ultrasonic backscatter: Theory and technique for optimization using a Gaussian form factor

Steering of a Sub-GeV Electron Beam through Planar Channeling Enhanced by Rechanneling

Contact Info

Product

Resources

About