Radio‐Frequency Acceleration System for the MURA 50‐MeV Electron Accelerator: Theoretical Considerations and Description. XI

Before giving a short report of the present status of the electron accelerator at Hamburg, let me describe very briefly the principal features of the design. The electron accelerator is a strong focusing synchrotron for accelerating electrons up to about 6 GeV. Such a machine differs in two essential features from a proton synchrotron: (i) At an injection energy of 40 MeV, the velocity of the electrons is practically equal to that of light, so no frequency modulation of the R. F. accelerating units is necessary. (ii) A very intense synchrotron radiation is emitted when an electron moves in a transverse magnetic field. Since the radiated power is inversely proportional to the fourth power of the rest mass of the accelerated particles, the radiation from electrons is about 10 13 times more intense than that from protons with the same energy. The radiation loss at 6 GeV amounts to 3.6 MeV per turn; so the radio-frequency power requirements are greatly increased. In addition, the motion of the particles is strongly influenced by radiation forces, and while the vertical betatron oscillations are damped, the radial betatron oscillations are rather strongly antidamped. Figure 102 demonstrates this effect. Further, particles can be lost from the stable region of the synchrotron oscillations by too small a radio-frequency amplitude of the accelerator units. Since the radiation loss per turn is inversely proportional to the radius, it was necessary to choose a rather large radius of curvature for the accelerator; namely 31.7 m. One accelerates 50 times per second to keep small the excursions of the particles from the mean orbit. The acceleration time is therefore about 10 ms. Figure 103 shows the dependence with energy of the oscillation amplitudes. One sees that the amplitudes reach a minimum in the region of 2 to 3 GeV, due to the adiabatic damping of the synchrotron and betatron oscillations, and afterwards they increase due to the radiation effects.

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Theoretical considerations on influence of circuit impedance to IMD2 measurement of radio-frequency bulk acoustic wave duplexers

2010 IEEE International Frequency Control Symposium ◽

10.1109/freq.2010.5556356 ◽

2010 ◽

Author(s):

Ken-ya Hashimoto

Keyword(s):

Acoustic Wave ◽

Radio Frequency ◽

Bulk Acoustic Wave ◽

Theoretical Considerations ◽

Circuit Impedance

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Theoretical considerations on influence of circuit impedance on IMD2 measurement of radio-frequency bulk acoustic wave duplexers

IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control ◽

10.1109/tuffc.2011.1852 ◽

2011 ◽

Vol 58 (3) ◽

pp. 671-674 ◽

Cited By ~ 2

Author(s):

Ken-ya Hashimoto

Keyword(s):

Acoustic Wave ◽

Radio Frequency ◽

Bulk Acoustic Wave ◽

Theoretical Considerations ◽

Circuit Impedance

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A New Radio Frequency Interference Filter for Weather Radars

Journal of Atmospheric and Oceanic Technology ◽

10.1175/jtech-d-17-0028.1 ◽

2017 ◽

Vol 34 (7) ◽

pp. 1393-1406 ◽

Cited By ~ 1

Author(s):

John Y. N. Cho

Keyword(s):

Radio Frequency ◽

Time Domain ◽

Radar Data ◽

Interference Filter ◽

Radio Frequency Interference ◽

Weather Radars ◽

New Radio ◽

Operational Systems ◽

Theoretical Considerations ◽

Sample Time

AbstractA new radio frequency interference (RFI) filter algorithm for weather radars is proposed in the two-dimensional (2D) range-time/sample-time domain. Its operation in 2D space allows RFI detection at lower interference-to-noise or interference-to-signal ratios compared to filters working only in the sample-time domain while maintaining very low false alarm rates. Simulations and real weather radar data with RFI are used to perform algorithm comparisons. Results are consistent with theoretical considerations and show the 2D RFI filter to be a promising addition to the signal processing arsenal against interference with weather radars. Increased computational burden is the only drawback relative to filters currently used by operational systems.

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Radio-Frequency System of the Cambridge Electron Accelerator

IEEE Transactions on Microwave Theory and Techniques ◽

10.1109/tmtt.1960.1124802 ◽

1960 ◽

Vol 8 (6) ◽

pp. 593-596 ◽

Cited By ~ 1

Author(s):

K.W. Robinson

Keyword(s):

Radio Frequency ◽

Electron Accelerator

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Optical Properties of HVEM Accelerators

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100114529 ◽

1975 ◽

Vol 33 ◽

pp. 180-181

Author(s):

A. Strojnik ◽

J.W. Scholl ◽

V. Bevc

Keyword(s):

Optical Properties ◽

Electron Accelerator ◽

Systematic Investigation ◽

Electron Source ◽

High Brightness ◽

The Past ◽

Wide Range ◽

Optical Behavior

The electron accelerator, as inserted between the electron source (injector) and the imaging column of the HVEM, is usually a strong lens and should be optimized in order to ensure high brightness over a wide range of accelerating voltages and illuminating conditions. This is especially true in the case of the STEM where the brightness directly determines the highest resolution attainable. In the past, the optical behavior of accelerators was usually determined for a particular configuration. During the development of the accelerator for the Arizona 1 MEV STEM, systematic investigation was made of the major optical properties for a variety of electrode configurations, number of stages N, accelerating voltages, 1 and 10 MEV, and a range of injection voltages ϕ0 = 1, 3, 10, 30, 100, 300 kV).

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