SVTRAD diodes integrated radiation dose

The SVTRAD system consists of 12 PIN diodes grouped into 4 modules: Forward West, Forwad East, Backward West, and Backward East. Each module contains a MID (middle) plane diode, located in the bending plane of the magnet, as well as a TOP and a BTM (bottom) diode located respectively above and below the MID plane. The temperature of each diode is measured by 2 surrounding thermistors. The output current from a PIN diode, apart from a pedestal current that has to be subtracted, is proportional to the instantaneous radiation dose.
In 2002, two diamond detectors of roughly the same size as the PIN diodes were installed in the backward end of the support tube. For those diodes the pedestal currents are lower and are almost independent from the temperature. These diamond detectors provide a measurement of the instantaneous radiation dose much more reliable that the other diodes.
The SVTRAD is the only subsystem that can abort the beams. That can happen in different cases:

A list of the SVTRAD fast aborts can be found here. For a more extensive description of the SVTRAD system, see the SVTRAD introduction web page.

The following plots show the radiation dose integrated by the SVTRAD diodes.

SVTRAD stable beams aborts and aborted injections

The following plots show the number of stable beams aborts or aborted injection due to SVTRAD for each day in the last two weeks. The left column is relative to fast aborts: upper plot for the injection, lower plot for stable beams. On the right are shown the number of timer activations (up) and the number of minutes on timer.

Diamonds instantaneous dose

The following plots show the instantaneous radiation dose seen by the diamonds. Due to the position of the beam lines, the east side of the detector is more sensitive to the LER and the west side to the HER. Shown is the ratio between the measured value and the expected one (calculated from the beam currents and the luminosity). This calculation is based on a background carachterization study made in january 2004.

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last modified by Viola Sordini, April 19 2007