1. for increasing of positrons production
Textured polycrystal
for increasing of positrons production
A.V. Shchagin
Kharkov Institute of Physics and Technology, Kharkov 61108, Ukraine
Belgorod State University, Belgorod , Russia
Oral paper at Channeling Charged & Neutral Particles Channeling Phenomena,
Sirmione-Desenzano del Garda, Italy, on September 25-30, 2016.

2. Now, positrons are produced in tungsten single-crystalline and amorphous targets, see, e.g., [1]. To regret, application of tungsten single-crystals is restricted because of a short dechanneling length of incident electrons. We propose to apply textured polycrystalline target for increasing of the positron production. The polycrystalline target can be produced as a set rolled tungsten foils and installed behind of a thin tungsten single-crystalline target. Application of textured polycrystalline target can increase the probability of the channeling of incident electrons and, hence, increase production of positrons. Channeling of electrons in textured (molybdenum) polycrystal recently has been observed in [2].
References
[1]. X. Artru, I. Chaikovska, R. Chehab, M. Chevallier, O. Dadoun, K. Furukawa, H. Guler, T. Kamitani, F. Miyahara, M. Satoh, P. Sievers, T. Suwada, K. Umemori, A. Variola, Investigations on a hybrid positron source with a granular converter, NIM B 355 (2015)

3. Production of positrons
In W single-crystal
In W single-crystal + amorphous
In W single-crystal + granular convertor

4. Common polycrystal Rolled textured polycrystal

5. Recently, channeling of 255 MeV electrons in 10 um rolled Mo textured foil has been observed
Y. Takabayashi, K. Ishiji, Observation of channeling effects for relativistic electrons in a polycrystal, NIM B 355 (2015)

6. Positron source with textured polycrystal
How to create thick textured polycrystal
Positron source with textured polycrystal

7. Results and discussion
Positron source with textured polycrystal is proposed
Research steps
Research of positron production in a thin textured foil is necessary to veryfy the conception
Research of tungstem foils textures are necessary to chouse the best foil thickness and texture alignments and to create thick textured target
Thanks for attention