%Operating procedures at the ANU                              Steve Chappell

\chapter{Operating Procedures at the ANU}

... or: How to succesfully create a beam and accelerate it onto the
right target. As always, refer to guidelines at the ANU. 

\section{Ion Sources}

\subsection{Startup procedure (Sputter Source)}

{\bfseries 1)} Turn on the 4 breakers (2, 3, 5 and  6) on front of source
rack. The extract volts should come on.\\
{\bfseries 2)} Over a {\itshape 30 minute period} run the ionizer up to
20 A.\\
{\bfseries 3)} Keep restoring the ionizer to 20 nA from time to time as
it falls. \\
{\bfseries 4)} Remove earthing hook from sputter rack and close perspex
gate. Hang hook on door handle.\\
{\bfseries 5)} On vacuum control racks that span the perspex door:\\
Check green ``Good'' lights are on.\\
Check ion gauge reads $\sim 4 \times 10^{-7}$.\\
{\bfseries 6)} Check 14UD tube pressures $\sim 10^{-8}$ (See rack near
door leading to lift).\\
{\bfseries 7)} Open level 5 isolation valve -- Press two buttons
together on rack above 90$^o$ inflection magnet.\\
{\bfseries 8)} Press ON switch on Box Voltage control panel (Top of rack
near door leading to lift). Blue light next to switch
should come on. Set Box volts to required value (usually 128.6 kV).\\
{\bfseries 9)} Check ionizer --- get it stable at 20 A.\\
{\bfseries 10)} Over a {\itshape 15 to 20 minute period} run ionizer up
in 3 Amp steps {\itshape (every few minutes and NO faster)} to about 30
A --- Check value logged in 14UD log.\\
{\bfseries 11} Switch LE cup current monitor to control room. Go to
remote! Check image slits OK (usually 1mm). Go downstairs and wait for
beam to build up on the LE cup. When pill is hot enough, turn the
reservoir on. Build up reservoir to previously logged value over
{\itshape 30 mins}.\\
{\bfseries 12} Scan 90$^o$ magnet strength to optimize for required beam
species.

Typical values for the source are:\\
15 kV extractor.\\
4-6 V (8-9V max) ionizer.\\
30V (60V max) Reservoir.

The best beam transmission is for 60\% on Einzel lens up/down control. Then adjust inflection magnet.

\subsection{Shutdown (Sputter Source)}

{\bfseries 1)} Turn ``Quick Cool'' on (See control rack near source
$\sim$ 35 cm from top). Hear gas come on.\\
{\bfseries 2)} Adjacent to the Quick Cool is the reservoir control.
Press down and run to zero (see bottom left gauge on inside rack.)\\
{\bfseries 3)} When reservoir temperature $< 50^o$, lower ionizer by
about 20\%.\\
{\bfseries 4)} Find Box Volts control (Rack near door leading to lift).
Turn volts down using ``$-$'' button and switch off.\\
{\bfseries 5)} Lower ionizer another 30\% or so.\\
{\bfseries 6)} Close level 5 isolation valve (On rack above 90$^o$ magnet).\\
{\bfseries 7)} Take hold of earthing hook. Open cage and attach hook to
ring below amonia bottle on source.\\
{\bfseries 8)} Halve the ionizer current.\\
{\bfseries 9)} After a couple of minutes halve the ionizer current again.\\
{\bfseries 10)} Wait a minute then run ionizer current to zero.\\
{\bfseries 11)} Wait around 3 minutes.\\
{\bfseries 12)} Turn off breakers 2, 3, 5 and 6 ONLY using switches on
front of source rack. The extract volts should go off.\\
{\bfseries 13)} Turn Quick Cool off.\\
{\bfseries 14)} Write anything to report in the appropriate source log book.

\section{Target Station}

{\bfseries 1)} Set the analyzing magnet to direct beam into the Linac
Hall or main experimental area.\\
{\bfseries 2)} Prepare the target station and beamline.\\
MEGHA is on Line A in the Linac Hall.\\
The 2m Chamber is on Line 3 in the main area.

\section{The 14UD}

\subsection{Startup}

{\bfseries 1)} Check that the (mid section) sublimer currents are zero
before turning on shafts.\\
{\bfseries 2)} Move charge voltage switch to on.\\
{\bfseries 3)} Switch shafts key to on.\\
{\bfseries 4)} Hit start on upper and lower shafts.\\
{\bfseries 5)} Switch charging motor key to on and hit start buttons.\\
{\bfseries 6)} Switch GVM terminal voltage stabilizer (TVS) to slits.\\
{\bfseries 7)} Turn up charging voltage control. Current will start
running through the resistors and is measured on low and high energy
tube ammeters.\\
{\bfseries 8)} Increase charging voltage to about 10 kV.\\
{\bfseries 9)} Adjust GVM voltage error to approx required potential.\\
{\bfseries 10)} Switch TVS to GVM.\\
{\bfseries 11)} Move triode needles inward. The triode current should
increase and the terminal voltage should rise to the GVM setting.  If
not adjust charging voltage and triode needle positions. Keep in the
green and out of the red on triode current meter.\\
{\bfseries 12)} Check hand valve above analyzing magnet is open.\\
{\bfseries 13)} Check image slits OK (usually 1mm).\\
{\bfseries 14)} Select appropriate line to control (e.g. line 3 in Area 1).\\
\\
The terminal potential corona stabilizer is usually set to ``stabilize''. If running at high MV it is usual to ``condition'' the machine for a while.\\
\\
If the machine sparks, lower the charging volts, wait for vacuum to
recover, then put volts back on.

\subsection{Shutdown}

{\bfseries 1)} Switch TVS to GVM.\\
{\bfseries 2)} Set zero volts on GVM.\\
{\bfseries 3)} Move triode needles out and reduce charging voltage to zero. Turn off panel switch\\
{\bfseries 4)} Stop the charging motors. Turn key to off.\\
{\bfseries 5)} Run down terminal and mid section sublimers.\\
{\bfseries 6)} Stop upper and lower shafts. Turn key to off.\\
{\bfseries 7)} Move charge voltage switch to off.\\
{\bfseries 8)} Turn 90$^o$ magnet and switching magnet controls down to
less than 50 A.\\
{\bfseries 9)} Leave all steerers, Quads and NMR as you have been using them.\\
{\bfseries 10)} Record all troubles/failures relating to the 14UD in
the fault log.

\subsection{Beam Transport}

{\bfseries 1)} Identify the distribution of charge states following
stripping at the central terminal for the required beam using the ANU
code STRIP. Access to the local computers is via account name ``charissa''.\\
{\bfseries 2)} Identify the precise analyzing magnet B-field for
the required beam using the ANU code UDFREQ. Set the NMR probe (An H$_2$O
sample irradiated with an R.F. field at a frequency determined by the
NMR gaussmeter tuning pot.) to the exact value given by the code then
adjust the B-field using the coarse and fine controls until resonance
is observed on the scope (The B-field induced energy level splitting of
the sample now matches the R.F. frequency.) {\itshape Please remember that
electromagnets follow a hysteresis loop. If reducing the field, cycle the
magnet by winding to max then min then to the required setting.}\\
{\bfseries 3)} The other machine settings (for the quadrupoles etc.) are
approximate. They will need adjusting to give the optimum beam transport.
In practise it is often more effective to take the machine parameters
from previously recorded settings (in the 14UD log book) and scale
according to the magnetic rigidity:
\begin{equation}
{
BR=\left(
\frac{2M_bE_b}{q^2}
\right)^{\frac{1}{2}}
}
\end{equation}
{\itshape i.e. NEW Magnet setting = OLD Setting X NEW NMR/OLD NMR.}\\
{\bfseries 4)} Tune all machine parameters to their approximate settings.\\
{\bfseries 5)} Ensure LE F.Cup is in place. Assuming source running OK
and that inflection magnet is set:\\
Adjust Einzel lens, control focus and steering to maximise current (set
console metering to LE cup.) {\itshape Nb. Low Energy Iris may be used
to reduce beam current.}\\
Tune beam with electrostatic quad controller.\\
Make fine adjustments to the inflection magnet control.\\
{\bfseries 6)} Remove LE cup and tune beam onto Tank cup.\\
{\bfseries 7)} Tune onto HE cup. {\itshape (Nb. The terminal lens may be
used at this point but make a note of the original settings.)}\\
{\bfseries 8)} Once beam is on the analyzing slits, the terminal voltage
may be stabilized by switching the charging voltage control from GVM to
slits and setting the appropriate feedback threshold.\\
{\bfseries 9)} Proceed with tuning the beam down the appropriate line.\\
{\bfseries 10} Use apertures/scintillator at the target position to do
the final focussing of beam and to determine the maximum beam spot size.\\
{\bfseries 11)} Record machine settings in the 14UD parameter log.\\
{\itshape (Nb. It is not necessary to record every energy setting for
a 100+ step excitation function measurement in the 14UD parameter log,
but wise to keep a record in the run book!)}\\
{\bfseries 12)} During the experiment record any unusual/interesting events
(e.g. sparks) in the 14UD log.

\section{The Linac}

{\bfseries 1)} The 14UD analyzing magnet is swung around and connected to the Linac Line.\\
{\bfseries 2) The 90$^o$ Magnet or ``Big Red'' in the Linac Hall:}\\
If no post-acceleration is required in the Linac booster, the 90$^o$ magnet
is set such that the beam is bent directly towards the switching magnet and
appropriate beamline (Line A for MEGHA) on entry to the Linac Hall.\\
If using the booster this magnet is set such that the beam drifts straight
through, is accelerated around the Linac, then drifts through the magnet
again at 90$^o$ to the original direction and on towards the switching
magnet and target station.\\
{\bfseries 2) How does it all work again?!}

