224 research outputs found
Transverse instability of the antiproton beam in the Recycler Ring
The brightness of the antiproton beam in Fermilab's 8 GeV Recycler ring is
limited by a transverse instability. This instability has occurred during the
extraction process to the Tevatron for large stacks of antiprotons even with
dampers in operation. This paper describes observed features of the
instability, introduces the threshold phase density to characterize the beam
stability, and finds the results to be in agreement with a resistive wall
instability model. Effective exclusion of the longitudinal tails from Landau
damping by decreasing the depth of the RF potential well is observed to lower
the threshold density by up to a factor of two.Comment: 3 pp. Particle Accelerator, 24th Conference (PAC'11) 2011. 28 Mar - 1
Apr 2011. New York, US
"Hollow cathode" gun optics
The generation of an electron beam by a hollow cathode gun in a cusp magnetic field is discussed. Such a gun is proposed for an electron cooling device without toroids. In a section with a homogeneous magnetic field, this beam experiences a disturbance region near the axis where the electron temperature becomes higher. The main purpose of the article is to define conditions for generating the beam so as to restrict the extent of this region as much as possible. It is shown that a state with a virtual cathode in the vicinity of the zero magnetic field point is the most suitable for this aim. The experimental and essential analytical results are presented
Transverse Instabilities in the Fermilab Recycler
Transverse instabilities of the antiproton beam have been observed in the
Recycler ring soon after its commissioning. After installation of transverse
dampers, the threshold for the instability limit increased significantly but
the instability is still found to limit the brightness of the antiprotons
extracted from the Recycler for Tevatron shots. In this paper, we describe
observations of the instabilities during the extraction process as well as
during dedicated studies. The measured instability threshold phase density
agrees with the prediction of the rigid beam model within a factor of 2. Also,
we conclude that the instability threshold can be significantly lowered for a
bunch contained in a narrow and shallow potential well due to effective
exclusion of the longitudinal tails from Landau damping.Comment: 17 pages, 'Technical' Note, Use of 'internal' jargon and reference
Development and Testing of Monoclonal Antibodies-Based Diagnostic Preparation for <i>Bacillus anthracis</i> Spores Detection Using Latex Agglutination Method
Immobilization of anti-B. anthracis monoclonal antibodies (MAbs) on latex microparticles was studied, the optimal load of these MAbs was determined to be 20 Β΅g for 50 Β΅l of the stock latex suspension. The highest sensitivity of latex agglutination test was observed for 1E6 MAbs. Latex suspensions with immobilized MAbs were lyophilized. Their sensitivity and specificity were shown to be highly competitive with those of the stock liquid latex suspension. Latex diagnosticum for Bacillus anthracis spores detection was constructed on the basis of these lyophilized reagents, developed and approved was the regulatory documentation that included their application instructions and technical specifications. Carried out were inter-laboratory and commission tests of experimental prototypes of the designed latex diagnosticum. These preparations demonstrated high sensitivity (from 1Β·105 to 2Β·106 spores/ml and even more) and specificity (absence of cross-reactions with spores of different species of sporogenous bacilli at concentration of 108 spores/ml)
Measurement of the cross section with the CMD-3 detector at the VEPP-2000 collider
The process has been studied in the
center-of-mass energy range from 1500 to 2000\,MeV using a data sample of 23
pb collected with the CMD-3 detector at the VEPP-2000 collider.
Using about 24000 selected events, the cross
section has been measured with a systematic uncertainty decreasing from 11.7\%
at 1500-1600\,MeV to 6.1\% above 1800\,MeV. A preliminary study of
production dynamics has been performed
Study of the process in the c.m. energy range from threshold to 2 GeV with the CMD-3 detector
Using a data sample of 6.8 pb collected with the CMD-3 detector at the
VEPP-2000 collider we select about 2700 events of the process and measure its cross section at 12 energy ponts with about
6\% systematic uncertainty. From the angular distribution of produced nucleons
we obtain the ratio
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