Possibility of crystal extraction and collimation in the sub-GeV range

Abstract

Bent crystal situated in a circulating beam can serve for efficient slow extraction or active collimation of the beams. This technique, well established at 1-1000 GeV, could be efficient also at the energies as low as 0.1-1 GeV according to the computer simulations presented in this paper. Applications might include halo scraping in the spallation neutron sources or slow extraction from medical synchrotrons.

<title>New radiation sources from channeling in micro- and nano-structures</title>

“…for 0.1-1 GeV/u ions of Fe +26 , as in Fig. 5, the divergence of the channeled beam in a nanotube of arbitrary helicity like (11,9) is 0.24-0.77 mrad. The size of the source could be quite small.…”

“…Two parameters were measured for each X-ray As proven by our experimental study, it is feasible to manufacture a crystalline undulator for channeling of radiating particles with a sub-millimeter period and with the amplitude of channel oscillations in the order of 20-40 Å, which is highly interesting for a novel radiation source [14,15]. Further on we have optimized the CU manufacturing process and were able to produce a series of undulators with the following parameters: the length along the beam 1 to 5 mm, thickness across the beam 0.3 to 0.5 mm, 10 periods of oscillation with period of 0.1 to 0.5 mm [11]. The oscillation amplitude was on the order of 50 A.…”

“…Ref. [11] gives a very preliminary analysis of the relative importance of the above-enlisted factors ( After the sine-like deformation of crystal was proven in X-ray tests, four undulators were tested for channeling in a beam of 70-GeV protons at IHEP. It was observed in the experiment that the crystal cross-section is efficiently channeling high energy particles, similarly to usual crystal deflectors (see [16]).…”

“…In [4] a Monte Carlo code was developed and simulations of particle channeling in bent single-wall nanotubes were carried out, aimed at finding how useful nanotubes are for channeling of positively-charged particle beams, what kind of nanotubes are efficient for this job, and how nanotubes compare with crystals in this regard [4]. We present then our recent experimental proof [7][8][9][10][11] for the feasibility of creation of a crystalline undulator (CU), review the scientific background for CU and propose the world-first experimental study of photon emission in the field of periodically deformed crystallographic planes serving as an undulator. The activities will be centered about two proposed accelerator experiments, one at LNF Frascati with 500-800 MeV positrons, and another one at IHEP Protvino with 2-10 GeV positrons.…”

Neutron characterization of aluminium nitride nanotubes

“…The lack of theoretical understanding makes it difficult to predict the related physical properties. Nanotubes have many interesting applications, including those based on particle channeling through micro and nanostructures [4,5]. AlN nanotubes are potential candidates for applications as gas sensors.…”