|Device Descriptions||Locations||Trip Values|
|Monitoring Software||Data Plots|
Trip settings have been enabled on many of the Booster BLM's. This has been
done in an attempt to limit losses in order to prevent excessive activation
of the accelerator components. We expect both the values of the alarm
settings and the number of BLM's involved to evolve with time, as we better
understand the correlations between BLM readings and activation levels in the
The ACNET devices to which the alarms have been applied are the B:BLxxx0
devices (where xxx is a 3 letter location description). These devices contain
sums of the total losses recorded on all beam resets (event 10's) during the
last 100 seconds and update every 17 seconds.
See BLM Location Descriptions for descriptions
and photos of the placement of all relevant BLMs.
Currently, upper limits are enabled on the following 60 BLM's:
In order to determine better trip points, We have attempted to fit the Loss
data to measured activation levels. The model used is a two-lifetime model with
a correction for very short lived activation.
Ai(t) = Ksi.Ssi + A1i.exp(-L1.T) + A2i.exp(-L2.T) + Ki.[ L1.S1(T) + L2.S2(T) ]
where: Ai(T) is the activation measured at location i and time T.
Lx is the decay constant for isotope x;
Ls = 9.24 (18F), L1 = 0.122 (52Mn), and L2 = 0.00229 (54Mn).
Sxi(t) is a time weighted integration of the losses recorded by the BLM associated with location i during the time period t. The weighting function is given by exp[-Lx.(T-t)].
The remaining parameters are determined by the fit.
The results of the fits are displayed in the following plots:-
In order to monitor past performance, B88 can also be used to produce
similar plots based on data extracted from the BLM2 data-logger.
Each of the ~120 B:BLxxx4 and B:BLxxxD devices are data-logged. This enables us
to monitor Booster performance with this system in a manner completely analagous
to way it is done with the Chipmunks. For stable
running periods, we record the average reading for each BLM and normalize it to
the corresponding alarm maximum. The largest value thus obtained, is normalized
to the beam delivery rate during that period in order to determine the maximum
protons/hour that could have been delivered without tripping one of the BLM's.
(A stable running period is a period of at least an hour in which neither the
protons delivered per pulse nor the pulse rate varied by more than 5%. Stable
periods are defined separately for x1D and x14 event types.
Long Term BLM monitoring ..