15 research outputs found
Studies and application of bent crystals for beam steering at 70-GeV IHEP accelerator
This report overviews studies accomplished in the U70 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 options emerge
for, say, LHC and ILC based on the "volume reflection" effect, which has been
discovered recently in machine study runs at U70 of IHEP (50 GeV) and SPS of
CERN (400 GeV).Comment: 12 pages, 14 figure
Proton Extraction from IHEP Accelerator Using Bent Crystals
IHEP Protvino has pioneered the wide practical use of bent crystals as
optical elements in high-energy beams for beam extraction and deflection on
permanent basis since 1989. In the course of IHEP experiments, crystal
channeling has been developed into efficient instrument for particle steering
at accelerators, working in predictable, reliable manner with beams of very
high intensity over years. Crystal systems extract 70 GeV protons from IHEP
main ring with efficiency of 85% at intensity of 1.E12, basing on multi-pass
mechanism of channeling proposed theoretically and realised experimentally at
IHEP. Today, six locations on the IHEP 70-GeV main ring of the accelerator
facility are equipped by crystal extraction systems, serving mostly for routine
applications rather than for research and allowing a simultaneous run of
several particle physics experiments, thus significantly enriching the IHEP
physics program. The long successful history of large-scale crystal
exploitation at IHEP should help to incorporate channeling crystals into
accelerator systems worldwide in order to create unique systems for beam
delivery. We report recent results from the research and exploitation of
crystal extraction systems at IHEP.Comment: Invited talk at the International workshop "Relativistic Channeling
and Related Coherent Phenomena", Frascati (Rome) 23-26 March 200
Double volume reflection of a proton beam by a sequence of two bent crystals
The doubling of the angle of beam deflection due to volume reflection of protons by a sequence of two bent silicon crystals was experimentally observed at the 400 GeV proton beam of the CERN SPS. A similar sequence of short bent crystals can be used as an efficient primary collimator for the Large Hadron Collider
High-efficiency beam extraction and collimation using channeling in very short bent crystals
silicon crystal was used to channel and extract 70 GeV protons from the U-70 accelerator with an efficiency of 85.3±2.8%, as measured for a beam of ∼1012 protons directed towards crystals of ∼2 mm length in spills of ∼2 s duration. The experimental data follow very well the prediction of Monte Carlo simulations. This demonstration is important in devising a more efficient use of the U-70 accelerator in Protvino and provides crucial support for implementing crystal-assisted slow extraction and collimation in other machines, such as the Tevatron, RHIC, the AGS, the SNS, COSY, and the LHC
First Results of Investigation of Radiation from Positrons in a Crystalline Undulator
The sensing properties of titanium oxide have been tailored through doping with niobium and dispersion of nanosized Au particles. The microstructural features of the gold-titania composite system were investigated by transmission electron microscopy and the electronic properties of Au nanoparticles were specifically investigated by electron holography. Holography provides quantitative determination of the mean inner potential with the high spatial resolution attained by transmission electron microscopy. Large increase of the mean inner potential has been measured for ultra small Au particles arising from the nano-scale assembling. Electrical tests were performed at low operating temperatures and demonstrated the considerable enhancement of CO sensitivity owing to the extremely high catalytic activity of gold particles
Advances in the investigation of the extraction of a proton beam from the U-70 accelerator with the aid of bent single crystals
The efficiency of the extraction of a beam from an accelerator is radically improved owing to the application of short crystals of length up to 1.8 mm bent through a small angle of about 1 mrad. This success is due to an increase in the multiplicity of particle transmission through the crystal used. A record efficiency of the extraction of 70-GeV protons in excess of 80% is achieved experimentally, this result being in agreement with theoretical predictions. It is shown that the crystal can efficiently operate at the injection energy of 1.3 GeV
Preliminary results on the study of radiation from positrons in a periodically deformed crystal
In the present experiment, the radiation from positrons moving in a periodically deformed crystal was observed for the first time. The spectra of radiation are measured in a wide range of energy. The experimental indication showing the existence of an undulator peak in radiation was obtained at a qualitative level and was confirmed by calculations. Crystal undulators provide an equivalent magnetic field of 1000 T and periods in the submillimeter range and consequently can be applied to the generation of X-rays and gamma-rays, of energies a hundreds times higher than the radiation in usual undulators
Double volume reflection of a proton beam by a sequence of two bent crystals
The doubling of the angle of beam deflection due to volume reflection of protons by a sequence of two bent silicon crystals was experimentally observed at the 400 GeV proton beam of the CERN SPS. A similar sequence of short bent crystals can be used as an efficient primary collimator for the Large Hadron Collider