排序方式: 共有31条查询结果,搜索用时 171 毫秒
1.
A. G. Afonin E. V. Barnov G. I. Britvich M. K. Bulgakov A. A. Durum M. Yu. Kostin A. V. Lutchev V. A. Maisheev Yu. E. Sandomirskii V. I. Pitalev I. V. Poluektov S. F. Reshetnikov Yu. A. Chesnokov P. N. Chirkov A. A. Yanovich 《JETP Letters》2017,105(12):763-765
It has recently been realized that the focusing of high-energy particle beams at a distance of about 1 cm is promising. A new idea is proposed in this work to focus the beam at a short distance by using a bent plane–parallel silicon plate whose side edges are rotated at a small angle with respect to crystallographic planes. At the U-70 accelerator (IHEP, Protvino), a 50-GeV proton beam has been focused to a narrow line with a width of no more than 30 μm at a distance of 17 cm. 相似文献
2.
V. T. Baranov S. Bellucci V. M. Biryukov G. I. Britvich C. Balasubramanian V. Guidi G. Giannini V. N. Zapolsky V. I. Kotov A. E. Kushnirenko V. A. Maisheev G. Martinelli E. Milan V. A. Pikalov V. I. Terekhov U. Uggerhoj V. N. Chepegin Yu. A. Chesnokov 《JETP Letters》2005,82(9):562-564
Radiation emitted by positrons moving in a periodically deformed crystal has been experimentally observed for the first time. Radiation spectra have been measured in a wide energy range. Experimental evidence has been obtained for an undulator peak in a radiation spectrum, which is qualitatively consistent with calculations. Crystalline undulators ensure an equivalent magnetic field of 1000 T and a period in the submillimeter range and can therefore be used to generate x-ray and gamma radiation that is a hundred times harder than radiation in usual undulators. 相似文献
3.
Yu. A. Chesnokov A. G. Afonin V. T. Baranov G. I. Britvich P. N. Chirkov V. A. Maisheev D. A. Savin V. I. Terekhov 《Journal of Experimental and Theoretical Physics》2018,126(1):115-125
Dependences of the tunnel magnetoresistance and in-plane component of the spin transfer torque on the applied voltage in a magnetic tunnel junction have been calculated in the approximation of ballistic transport of conduction electrons through an insulating layer with embedded magnetic or nonmagnetic nanoparticles. A single-barrier magnetic tunnel junction with a nanoparticle embedded in an insulator forms a double-barrier magnetic tunnel junction. It has been shown that the in-plane component of the spin transfer torque in the double-barrier magnetic tunnel junction can be higher than that in the single-barrier one at the same thickness of the insulating layer. The calculations show that nanoparticles embedded in the tunnel junction increase the probability of tunneling of electrons, create resonance conditions, and ensure the quantization of the conductance in contrast to the tunnel junction without nanoparticles. The calculated dependences of the tunnel magnetoresistance correspond to experimental data demonstrating peak anomalies and suppression of the maximum magnetoresistances at low voltages. 相似文献
4.
S. Bellucci Yu. A. Chesnokov P. N. Chirkov M. Ćosić G. Giannini V. A. Maisheev S. Petrović I. A. Yazynin 《JETP Letters》2014,98(11):649-651
The phenomenon of the deflection of a charged particle beam due to channeling in a bent crystal is thoroughly investigated and successfully applied for the extraction of the beam in high-energy accelerators, at the energies of about 10 GeV and higher. However, a big practical interest lies in the task of bending and extracting charged particles with energies below 1 GeV, for example, for the production of ultrastable beams of low emittance for medical and biological applications. That is why a novel crystal technique, namely thin straight crystal targets, is investigated in this article, using crystals as elements for extraction and collimation of the circulating beam in a ring accelerator. The advantages of reflection in straight crystals in comparison with bent crystal channeling consist in the small length of straight crystals along the beam that reduces the amount of nuclear interactions and improves the background. Experimental results were obtained for the bending of a 100 MeV positron beam with using five sequential straight crystals. 相似文献
5.
A. G. Afonin V. M. Biryukov V. A. Gavrilushkin V. N. Gres’ B. A. Zelenov V. I. Kotov V. A. Maisheev A. V. Minchenko V. I. Terekhov E. F. Troyanov Yu. A. Chesnokov M. G. Gordeeva A. S. Denisov Yu. M. Ivanov A. A. Petrunin V. V. Skorobogatov B. A. Chunin 《JETP Letters》1998,68(7):568-572
A record-high particle extraction efficiency, exceeding 40%, in agreement with theoretical predictions, is achieved using
a short (5 mm long) crystal bent by 1.5 mrad. An extracted beam intensity of ∼6×1011 protons per cycle is obtained. This is five to six orders of magnitude higher than previous results.
Pis’ma Zh. éksp. Teor. Fiz. 68, No. 7, 544–548 (10 October 1998) 相似文献
6.
A. G. Afonin G. I. Britvich A. P. Bugorskii M. K. Bulgakov A. A. Durum M. Yu. Kostin A. V. Lutchev V. A. Maisheev Yu. E. Sandomirskii V. I. Pitalev I. V. Poluektov Yu. A. Chesnokov P. N. Chirkov A. A. Yanovich 《JETP Letters》2016,104(1):12-14
At large accelerators, bent crystals are employed to deflect weakly divergent proton beams at the stages of extraction and collimation. We demonstrate that a divergent particle beam may be efficiently deflected using a crystal with a focusing edge. A proton beam with divergence near 1 mrad, which exceeds the Lindhard angle by a factor of 30, has been experimentally deflected by 1.8 mrad with efficiency near 15%. The proposed focusing crystal may serve as an element of a novel optical system for secondary-particle beams in the TeV energy region. 相似文献
7.
V. I. Kotov A. G. Afonin V. T. Baranov V. M. Biryukov Yu. M. Ivanov A. A. Kardash V. A. Maisheev V. I. Terekhov E. F. Troyanov Yu. S. Fedotov V. N. Chepegin Yu. A. Chesnokov 《Physics of Atomic Nuclei》2005,68(6):1025-1033
The application of bent crystals for extracting accelerated beams from high-energy accelerators is reviewed. The results of realizing highly efficient extraction of protons from the IHEP accelerator are presented. Proposals on using oriented crystals for designing efficient positron sources at linear colliders and on developing new undulators are discussed. 相似文献
8.
A. G. Afonin V. T. Baranov M. K. Bulgakov I. S. Voinov V. N. Gorlov I. V. Ivanova D. M. Krylov A. N. Lun’kov V. A. Maisheev S. F. Reshetnikov D. A. Savin E. A. Syshchikov V. I. Terekhov Yu. A. Chesnokov P. N. Chirkov I. A. Yazynin 《JETP Letters》2011,93(4):187-190
The possibilities of the extraction and collimation of a circulating beam by a new method due to the reflection of particles in crystals with axial orientation were experimentally investigated in the Fall 2010 run at the U-70 synchrotron. Such crystals have positive features, because the axial potential is five times larger than the planar potential. It has been shown that the collimation efficiency can reach 90% due to axial effects in the crystal. Losses of the circulating beam on a collimator have been reduced by several times; this makes it possible to suppress the muon jet near the steel collimator of the circulating beam. 相似文献
9.
D. Alde F. Binon C. Bricman S. V. Donskov P. Duteil M. Gouanère A. V. Inyakin D. B. Kakauridze V. A. Kachanov G. V. Khaustov A. V. Kulik J. P. Lagnaux A. A. Lednev V. A. Maisheev Yu. M. Melnik Yu. V. Mikhailov Th. Mouthuy J. P. Peigneux A. Possoz Yu. D. Prokoshkin Yu. V. Rodnov S. A. Sadovsky P. M. Shagin D. Sillou A. V. Singovsky J. P. Stroot V. P. Sugonyaev 《Zeitschrift fur Physik C Particles and Fields》1984,25(3):225-229
The partial widths of η-meson decays η→2γ, η→3π0 and η→π0γγ have been measured in a high accuracy experiment made at the IHEP accelerator with the hodoscope electromagnetic spectrometer GAMS-2000. An upper limit has been determined for the 3γ channel. The Dalitz plot of the η decay into 3π0 shows that the matrix element does not depend on the pion energy. 相似文献
10.
S. Bellucci C. Balasubramanian A. Grilli F. Micciulla A. Raco A. Popov V. Baranov V. Biryukov Yu. Chesnokov V. Maisheev 《JETP Letters》2006,83(3):95-97
We observe positron bending by a crystal lattice, presumably being guided by a channeling phenomenon, deflecting the beam
by about 10 milliradian over a length of 1 mm of silicon. This technique may lead to the use of the channeling effect for
steering particle beams at energies below 1 GeV, for the purpose of producing beams of low emittance with enhanced stability
for medical and biological applications.
The text was submitted by the authors in English. 相似文献