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\newcommand{\oo }{$^{16}$O}
\newcommand{\mg }{$^{24}$Mg}
\newcommand{\na }{$^{23}$Na}
\newcommand{\be }{$^{8}$Be}
\newcommand{\si }{$^{28}$Si}
\newcommand{\su }{$^{32}$S}
\newcommand{\neon }{$^{20}$Ne}
\newcommand{\ca }{$^{40}$Ca}
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\begin{document}

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\noindent
\begin{minipage}[t]{10cm}
\fbox{
\parbox[t]{5cm}{
{\large {\bf Minutes}}\\[2mm]
Charissa Group Meeting
}}\\[7mm]
\makebox[3.5cm][l]{Meeting held on:} 27 August 1997\\[2mm]            % Date
\makebox[3.5cm][l]{Meeting held at:} Birmingham \\[2mm]     % Place
\end{minipage}
\hfill \raisebox{-2.5cm}{
\psfig{figure=char-encap.ps,height=3cm}}\\[2mm]

\begin{center} \begin{tabular}{l@{~~}l} \hline
~\\								% Present
\makebox[2.5cm][l]{Present:} & \parbox[t]{12cm}{
BRF(Chair),WNC,SPGC,NMC,RC,MF,
GRK,JSL,JTM,WDMR,\\SMS,GT,RPW,DLW
}\\
~\\								% Distribution
\makebox[2.5cm][l]{Distribution:} & \parbox[t]{12cm}{
Those above plus  RAC,NC,NJD,RAH,PJ,JK,RCL,VP,DDW,\\ all by e-mail/file-server 
}\\
~\\ \hline
\end{tabular} \end{center}
~\\[0.5cm]
%\addtolength{\headheight}{2.5cm}
{\large {\bf Minutes}} \\[0.5cm]

\noindent 
\begin{list}{\bf \arabic{agenda}.}{\usecounter{agenda}
\setlength{\labelsep}{0.2cm}
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\item	 {\bf Apologies:} received from RAC, RCL, NJD and VP.\\

{\bf Welcome:} Richard Cowin (York) was welcomed to his first meeting.\\

 {\bf Minutes of meeting of 26 February 1997:} accepted.\\


 
\item	 {\bf Actions from last Meeting:} 

\begin{enumerate}

\item {\em Item 7(c):} Draft of the paper on the DA system (RAH,MF) had
been delayed due to work on the system itself.

\item {\em Item 7(d):} SMS and MF would discuss $^{16}$O + \cc\ further.
Drafts by CDJ,SPF,PL had been passed to SPGC who was dealing with them.


\end{enumerate}

\item	 {\bf EPSRC news:} 

\begin{enumerate}

\item BRF reported a joint EPSRC/industry meeting held in Birmingham,
	9 May. 
\item The request via EPSRC from the EPSRC-Strasbourg Joint
	Management Committee for reactivation of the group to
	oversee the Charissa beamline at
	Strasbourg was discussed. No clear tasks could be established for
         this group, and it was decided to ask Lucy Brady to check back with
	the JMC regarding the need for such a group.
\item BRF reported that the EPSRC business plan was being finalised, and that
	the IOP had been approached for comment. 
\item The ANU review: no official news yet on renewal, but the meetings seemed
	to go well. Support was shown at the review, for the idea of
	providing technical manpower at ANU.

\end{enumerate}



\item	 {\bf Strasbourg Experiments:} 

\begin{enumerate}

\item {\em Beam test and decay width experiment }

JTM reported that set-up was scheduled for 17--23 Sep prior to two beam
periods ending on 12 Oct. Experiment to measure $\Gamma $(\cc \cc )/$\Gamma $
following \cc (\oo ,\mg )\al . Gas handling and DAQ to be set up. RPW and SMS
had already moved equipment from GANIL to Strasbourg and unpacked it into
racks. Two CAMAC crates were needed, and the gas system at York. It was noted
that there is no facility for off-line analysis.

\item {\em Li + Pb fusion run }

GRK reported on the experiment planned to measure $^{6,7}$Li + $^{207,208}$Pb
fusion using radioactivity measurements of the products (halflives 100ms
to hours). Expect beam in November. Detectors are needed to plan the mounts,
and assistance is available from the Birmingham workshops. \action{GRK}

\item {\em Other plans }

DLW outlines two approved proposals: (a) to test MEGHA modules, (b) to measure
\mg\ breakup at small angles (requires source development; hope for Nov/Dec
running).

\item {\em DAQ and electronics remaining at Strasbourg }

The default plan is to bring the system back to GANIL in January 1998
unless there are more experiments approved at the PAC on 12 Sep. BRF
reported that $^{9}$Be breakup and DEMON experiments were being contemplated
for Strasbourg in Sep 98.

\end{enumerate}


\item	 {\bf ANU Experiments:} 


\begin{enumerate}

\item {\em Next month's trip }

SMS, PJ, BRF and WDMR were leaving imminently, followed by others according
to a schedule distributed earlier by BRF by email to the whole collaboration
on 22 May. This schedule was reviewed at the meeting. The aim was to allow
hybrid or strip running with the new DAQ, and with a choice of target
positions (new target spans 6\degree\ to 52\degree ). One week of beam tests was
scheduled and SPGC had arranged a standby experiment. A final shipment was
due to leave York on 11 Sep.

After this trip, the only remaining tasks are expected to be:
\begin{enumerate}
\item new trigger system (see next paragraph)
\item remove coupling of CsI and gas signals
\item allow vacuum target loading
\item reorient detectors to second target position
\item redesign preamp motherboard
\end{enumerate}

It was noted that the last two of these could be linked, and that the
reorientation may imply a redesign of the back plates of the modules as well
as the mounting plate.

\item {\em New trigger system and strip detector setup }

MF reported that the trigger components were assembled, and required about
2 months of debugging tests with a PC. It should be ready in Dec 97, for
shipping to ANU, but interfacing with the DAQ will need careful checking,
including an estimated 2 days of beamtime.

The strip detector setup was mechanically complete and ready for installation
in Sep 97.

\item {\em Future experiments at ANU }

BRF reminded everyone about the summer school at ANU 12--23 Jan 98, which
could conveniently be linked to running time. He also reported that the gas
stripper was being installed in the 14UD, and that 3 weeks of linac running
were anticipated between 11 Nov 97 and 15 Jan 98. Interest was expressed
in January running (SPGC, DLW) and Easter running (MF, CDF, WNC/NC). It
seemed feasible to consider strip detector running in January, and SPGC 
stressed an urgent need for a long run (cf.\ Item 13).

It was anticipated that requests for Jan--Dec 1998 running would be called for
in Sep or Oct 1997. \action{ALL}

\end{enumerate}



\item	 {\bf GANIL Experiments:} 

\begin{enumerate}

\item {\em Report on recent runs }

Experiments had taken place in May [p($^{11}$Be,d)$^{10}$Be on SPEG, using
10 2D PSD's], July: [p($^{12}$Be,$^{6}$He$^{6}$He)p on LISE+DEMON] and
[C/Ta($^{14}$Be,$^{12}$Be\,n\,n)C/Ta on LISE+DEMON].

Lessons had been learnt about the 2D Si detector wiring and the CsI detector
nonlinearities. The matching of corner resistors  to the sheet
resistance, and the dependence of position resolution on the deposited energy
were important for the Si detectors. The nonlinearities for high pulse heights
in the CsI was found to include an effect due to loading of the preamp supply.

\item {\em Discussions with LPC on future array and DA }

Discussions at the beginning of July at LPC Caen had identified areas where
urgent planning was required for a new detector array and the provision
of amplifiers and electronics. The DAQ from ANU, now very old and hard to
keep supplied with spares, could be replaced. A VME-based system was envisaged,
that could interface with EXOGAM, DEMON, etc.\ which operate on VXI. LPC
could share costs on developing electronics if it were to be based at GANIL.
It was planned to reconvene before the end of November, to decide on these
matters and the spending needs. \action{MF,WNC}

\item {\em Future experiments at GANIL }

Proposals from WNC and MF were planned, for running with DEMON when it
returns to GANIL in spring 1998. The PAC in December will probably not
ask for SPIRAL requests. 

\end{enumerate}



\item	 {\bf Matching preamp-amp-detector combinations:} 

The performance of Charissa amplifiers for 2D Si detectors and CsI detectors
was discussed. Performance figures were provided by SPGC in the two
documents CH/DOC/ 97/02 and CH/DOC/97/03, which were discussed in detail.
An analysis of SPGC's tests by SPGC and WDMR showed that
it was not clear whether anything other than capacitive
noise was limiting the performance significantly, and the Charissa amplifier
performance could be improved if necessary by using more expensive components.
The resolution requirements for heavy and light ions could differ, because
heavy ion resolution was invariably target limited and the electronics
requirements were more relaxed.

However, other experience seemed to show that environmental noise 
was an important
contribution, and that a sophisticated filtering network was advantageous,
especially for the 2D detectors.

The recent running at GANIL had identified that unipolar pulses gave better
performance for CsI and Si detectors. The shaping times for corner and energy
signals for Hamamatsu and Eurisys 2D detectors, and for CsI detectors, were
all different, and a selection of at least four shaping times was
desirable. The original Charissa amplifiers, modified at GANIL and now at
Strasbourg, were starting to show their age and reliability was a concern.

Tests of the CAEN n568 hex-NIM amplifier were required. This offers improved
and versatile performance potentially, at a higher initial cost. MF agreed to
conduct tests at Birmingham with the Surrey amplifier. \action{MF,WNC}

\item	 {\bf Report from Vic Pucknell:} 

BRF relayed a report emailed by VP (away in USA). The MIDAS system had been
implemented under Windows95 and NT. There was a query about what demand
existed for DLT data. The combination of a 2000XT drive and Compact Tape 3
was recommended at this stage. SMS reported that he had collected information
about DLT choices. It was decided that there was no pressing need to
invest in DLT's at the moment.

\item	 {\bf Detector inventory:} 

The inventory on the web had been begun. All 2D detectors were included
except for detector recently used at GANIL (10 Eurisys and 2 Hamamatsu)
and one just taken to Surrey (Hamamatsu). York retained sufficient to fill
the 2 spare MEGHA modules with Hamamatsu detectors. Strip detectors were
not yet on the inventory.

The scheme now allows each group to edit a file on the server,\\ see
http://nnsa.dl.ac.uk/Charissa/documents and select 
{\em a-www-index-is-here}.

Detector inventory to be completed at each group. \action{NMC,NC,SPGC,DLW}

\item	 {\bf Experiments planned at other facilities:} 

JTM reported that his Argonne proposal had been approved, and that it was hoped
to run in Feb/Mar 1998. The experiment would require essentially the
equipment presently at Strasbourg. It would be important to ensure that it
was available for the GANIL running anticipated for the 
spring. \action{JTM}

WNC reported that RCL and he were submitting a proposal to the imminent
MSU PAC to do d($^{27}$P,$^3$He)$^{26}$Si using the S800 spectrometer, and
that the preferred time for the collaborators was also spring 1998.
The equipment required was 12 detectors and 60 channels of preamplifiers,
although RCL was looking at increasing this by 4 detectors. It may be
necessary to purchase more detectors in addition to the ones used recently
at GANIL. \action{WNC}

\item	 {\bf Grant Spend:} 

Progress on the grant spend was briefly reviewed.

\item	 {\bf New students:} 

New students were confirmed as starting with the groups at Oxford
(Charles Bremner, ex-Surrey), Surrey (Kate Jones, ex-Surrey) and
York (name unavailable). In addition, York would have an M.Sc.-by-research
student. Birmingham would have one new student starting in the nuclear physics
group.

\item	 {\bf Any other business:} 

SPGC discussed the implications of the referee's report on the manuscript
describing a study of the E$_{cm}$ = 32 MeV six-alpha 
resonance in the $3^- / 3^- $ channel. Extra data would be required in
order to measure spins, and this was a priority.

A meeting to assess the progress made in the forthcoming ANU trip should
be arranged before the end of October. \action{BRF}

A meeting to decide on the needs for electronics, data acquisition
and array construction for GANIL should be held, including N.\ Orr (LPC),
before the next collaboration meeting at the end of November. \action{MF}

A broad-brush summary of the experiments that have been discussed is given
in the following table. 
Timings are fairly notional at this stage, but serve to highlight
the operational considerations.

\begin{center}
\begin{tabular}{rccl} \hline
Month & Laboratory  & Detectors  & Names \\ \hline
Oct 97 & Strasbourg & hybrids    & JTM \\
Dec 97 & Strasbourg & hybrids    & GRK,DLW \\
Jan 97 & ANU        & strips in MEGHA    & SPGC,DLW \\
Feb 97 & ANL        & strips     & JTM \\
Mar 97 & MSU        & 2D Si      & RCL,WNC \\
Apr 97 & ANU        & strips AND MEGHA & MF,BRF,NC \\
May 97 & GANIL      & 2D,CsI,DEMON & WNC,MF \\
Sep 97 & Strasbourg & hybrids,DEMON & BRF \\ \hline
\end{tabular}
\end{center}

\item	 {\bf Date of next meeting:} 

The next collaboration meeting would be arranged for the end of November.

\end{list}

\vfill

\noindent
W.N. Catford, Secretary.\hfill
September 24, 1997  (released \today )


\end{document}















