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- P. Evtushenko, R. Schurig
FZR, Forschungszentrum Rossendorf, Dresden, Germany
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The ELBE radiation source is based on a superconducting linac. Initially
it was designed to be used in CW mode with repetition rates either 13 MHz
either 260 MHz. Later it was decided to operate the accelerator with
reduced repetition rates for diagnostic reasons and for certain users.
Now it is possible to operate at repetition rate 13/n MHz, where n can be
2, 4, 8, 16, 32, 64, and 128. It is required that the BPM system supports
any of these operation modes. A core element of the BPM electronics is a
logarithmic amplifier AD8313 made by Analog Devices Inc. The logarithmic
amplifier is a direct RF to DC converter rated up to 2.5 GHz. Initial
design of the BPM electronic was sophisticated only for CW operation with
repetition rate more than 10 MHz, since bandwidth of the AD8313 is
about of 10 MHz. Additionally a sample and hold amplifier is built in to
provide enough time for an ADC to make measurements. The sample and hold
amplifier is synchronized with a micropulse frequency. In the paper we
present results of the modified BPM electronics test.
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