1. Crystal channeling 2009 A. Afonin, IHEP, Protvino New results of use and research of crystals at U-70. A.Afonin, IHEP, Protvino 4- th Crystal channeling Workshop March 24-27, 2009

2. Crystal channeling 2009 A. Afonin, IHEP, Protvino

3. This report overviews studies accomplished in the U-70 proton synchrotron of IHEP- Protvino during the recent two decades. Major attention is paid to a routine application of bent crystals for beam extraction from the machine. It has been confirmed experimentally that efficiency of beam extraction with a crystal deflector of around 85% is well feasible for a proton beam with intensity up to 1012 protons per cycle. Another trend is to use bent crystals for halo collimation in a high energy collider. New promising option are on the “ volume reflection” effect, which has been discovered recently in machine study runs at U-70 of IHEP (50Gev) and SPS of CERN (400Gev). Perspective to use bent crystals for extraction of light ions from the U-70 accelerator are also presented.

4. Crystal channeling 2009 A. Afonin, IHEP, Protvino Ideas of use the particle channeling in bent crystal for steer the beams have been checked up and advanced in many experiments. This method has found the widest practical application on U-70 accelerator of SRC IHEP, where crystals are used in regular runs for beam extraction and forming. In 1989 a proton beam with energies 50 and 70 Gev was extracted by bent silicon crystals (65*15*0.6 mm and angle 85mrad). In this case the extraction efficiency was  10-4. The development of high efficiency extraction with short (1-5 mm) crystals (bending angles 1-2 mrad) was started at IHEP accelerator in 1997 and completed mostly by the end of 2001 with efficiency  85%.

5. Crystal channeling 2009 A. Afonin, IHEP, Protvino Schematic diagram of beam extraction from the U-70: Si19,Si 22, Si30, Si84, and Si106 are bent crystals; T24, T27 are the internal targets; I is the region of experimental systems and II is the region of crystal studies.

6. Crystal channeling 2009 A. Afonin, IHEP, Protvino

11. The utilization of magnetic cycle flattop

12. Crystal channeling 2009 A. Afonin, IHEP, Protvino Работа систем вывода в 2008г. Система Установки Время работы, Час 1с. 2с 1с 2с БВ 2 2 336 672* МРВ/СМВ 2 2 216 504 МВК 5 5 336 672 ВМ 3 4 336 672

13. Crystal channeling 2009 A. Afonin, IHEP, Protvino

14. Crystal channeling 2009 A. Afonin, IHEP, Protvino Beam splitting. Usually a beam is split by an electrostatic or a magnetic splitter. This is a technically fairly complex approach requiring considerable space, since the angles of deflection of a beam by a conventional splitter are very limited. The use of crystals provides a simple means for beam splitting, which is unattainable by conventional techniques.

15. Crystal channeling 2009 A. Afonin, IHEP, Protvino

17. Use bent crystals for extracting and splitting confirmed the advantages of this method: quite high efficiency high stability of extracted beam parameters the possibility of fast tuning over a wide range of intensities the possibility of simultaneous operation

18. Crystal channeling 2009 A. Afonin, IHEP, Protvino

28. Beam spot on TV-screen

29. Crystal channeling 2009 A. Afonin, IHEP, Protvino

36. Beam spot on emulsion

37. Crystal channeling 2009 A. Afonin, IHEP, Protvino Nearest plans: During 1 run of machine operation (1- 24/04/09) to test 8 new deflectors: 6 multi-crystals 2 “long” crystals (100mrad and 170mrad). To organise new experimental station in SS26 and to start at november new experiments.

38. Crystal channeling 2009 A. Afonin, IHEP, Protvino CONCLUSION Bent crystals are very promising for application at accelerator for beam extraction/collimation and generation of powerful photon radiation.