{\sc \today}\\*[1cm]
\end{center}
\section{Goals: }
The primary goal of the May run is to verify that all of the hardware is
working properly and that the hardware operating parameters are set to
proper values. A second goal is to verify that software methods to detect
problems as well as software calibration methods are working.
We particularly note non-standard running conditions which the drift chamber
group requests.
\subsection{Specific Strategies: }
\begin{itemize}
\item SET OPERATING PARAMETERS
\begin{itemize}
\item Gas Mixture - we are currently working with Ar/CO2 and He/CO2 mixtures.
We must determine that the chosen ratio (now expected to be 90/10 Ar/CO2 for
Regions 1 and 3, and possibly Region 2 also) yields values of Tmax which are
on the order of 1000 ns or less. If not, we will consider changing the
output width of each of the ADB boards or putting more effort into software
identification of double pulsing. We must also determine that at the
nominal operating voltage, which yields an efficiency of $98\%$ or greater,
the chamber is not producting "after-pulses" due to lack of quenching.
This type of hit analysis {\bf requires writing out of the raw data and may
require runs with longer than normal time windows.}
\item Voltage - because we wish all of the chambers to be equally sensitive
to small primary ionizations (several electrons threshold) and because the
electronic amplification is the same for all regions, we want to run all of
the chambers at EQUAL GAS GAIN. {\bf Special purpose runs with ADC's on some wires
may be necessary because the chambers are not all running with the same
gas mixture (Region 1 bubbles through isopropyl alcohol).}
\item Discriminator Threshold - the level will be set to the minimum which
allows adequate electronic noise rejection. {\bf A series of runs with changing
threshold (in one superlayer from each region) will allow us a quantitative
study of the electronic noise rate.} Note that if the threshold is changed
the high voltage must also be changed to maintain equal gas gain.
\item Time Windows - to reduce the amount of data written to tape we would like
to reduce the TDC readout time window to a minimum. We must be careful in setting
the window for Region 2 that it is wide enough even for the high-B regions of the
chamber. We may need some {\bf runs with non-standard time windows.}
\end{itemize}
\item DETERMINE OPERATIONAL CHARACTERISTICS
\begin{itemize}
\item Catalog of Problems - using the raw data hit analysis programs and the
online monitoring program we will determine which wires are not functioning and
the cause. This information must be loaded into the status word of the
time calibration bank. For this study, we need a {\bf high statistics run
at nominal operating conditions.}
\item Efficiency - using tracks we will determine the layer efficiency of the
chambers for different areas of the chambers and also as a function of the
tracks' position within the drift cell. We will take these {\bf runs at nominal
operating condition}; we will need special reconstruction software which
can fit individual superlayers and which can remove designated layers from
the fit.
\item Resolution - determining the resolution of the chamber requires a complete
calibration - of time, drift velocity and geometry. We can eliminate most geometry
effects by using single superlayer track-fitting. This requires {\bf runs at nominal
operating conditions.}
\item Noise Level - noise arises from several sources: electromagnetic pickup by
the wires, ground loop related noise, response to low-energy ionizing radiation
(x-rays and Moller electrons, mainly), excessive activity caused by high ionization
(hot wire) possibly in a feedback environment. To quantify the noise will require
{\bf runs with special conditions: changed discriminator threshold for certain ADB
crates, runs with reduced high voltage to look for purely electronic noise,
runs with elevated high voltage to look for hot wire problems. We may want a
run with an extended time window to search for time structure in the noise.}
Since these studies involve hit analysis, we will need the raw data.
\item Expected Chamber Lifetime - at nominal operating conditions, the amount
of current drawn by the chambers as a function of luminosity will allow us to
estimate the working lifetime of the chambers.
\end{itemize}
\item ESTABLISH OPERATING PROCEDURES
\begin{itemize}
\item Daily Checklist -
\item Standard Run Display - look at histograms of run-dependent quantities
in search of changes from constancy.
\item Expert Diagnostics - establish standard methods to track down problems
detected by looking at changes in the Standard Run Display.
\item High Voltage Operating Procedures - turn-on (cold, after trip, etc.),
standard trip levels (designed for early detection of chamber discharges and
to allow a long chamber lifetime), monitoring.
\item ADB/TDC Operations - establish a checklist to debug DAQ hardware problems.
\end{itemize}
\item VERIFY PROBLEM DETECTION PROCEDURES
\begin{itemize}
\item Monitoring Histograms - establish a standard set of hit and time distributions
which can quickly reveal the most common problems - missing or dead wires, hot wires
(distinguish between electronic oscillations and chamber-related hot wires),
and disconnections (HV, lv or signal).
\item Automatic Monitoring and Analysis Programs - develop software to automatically
search for the problems evident in the monitoring histograms.
\item {\bf Special Runs - we should take some runs with the hardware deliberately set
to malfunction in order to test our problem detection procedures}, especially for
subtle problems or for problems which are anticipated to occur frequently.
One example is to disconnect a HV bus for a field wire layer and see whether we
can detect quickly the resulting lower gain of the adjacent sense wire layer.
Another example is to disconnect certain channels and determine whether the
automatic monitoring programs accurately identify the dis-connection.
\end{itemize}
\item SUMMARY of SPECIAL RUN or DAQ CONDITIONS REQUIRED
\begin{itemize}
\item Runs with different time windows for TDC readout.
\item Runs with charge measurement circuitry on selected wires.
\item Runs with different ADB thresholds for selected crates.
\item Runs with reduced HV to look for electronic noise problems.
\item Runs with elevated HV to look for hot wire problems.
\item Runs with selected HV ``baby" cables for field wires disconnected.
\item Runs with selected lv and signal cables disconnected to test problem finder.
\end{itemize}
\end{itemize}
\end{document}