Minutes of the Meeting 17. September 2002, prepared by SE

present:
Dave Ottewell, Dave Hutcheon, Art Olin, John D'Auria, Lothar Buchmann, Peter
Machule, Dario Gigliotti, Alison Laird, Shawn Bishop, Sabine Engel

agenda:
1. last week's minutes
2. report on recent 24Mg(p,g) run
3. Sabine's practice talk
4. business arising
5. job list

1. minutes:
DAH pointed out two tiny corrections: ". to stop leakage from inner cell"
and a typo in "pursue"

2. report on recent 24Mg(p,g) run:
JDA: The Mg source died Monday night. So importance of further stable Mg
beam time was discussed.
SE & DAH: The measurement of the low resonance at E_cm =214 keV was finished
over the weekend. The resonance energy measured with MD1 agrees very well
not only with the published value, but also with the Prague magnet. The
analysis has just started, but no value for wg is available yet. However,
all runs agree within each other. No charge state distribution was measured
for the recoils.
Since spring three acceptable sets of resonances in the 24Mg(p,g) reaction
were measured with the DRAGON. The strength observed for the resonance at
402 keV agrees very well with the value published by Christian Iliadis (42
+/- 3 meV), just the energy was not measured. For the resonance at 790 keV
the DRAGON value (403 +/- 50 meV) agrees with Trautvetter and van Reenen
(both 490 +/- 100 or 70), yet not with Iliadis (who did not measure but
scale the resonance strength).
It was concluded that there is no immediate need to request more 24Mg beam
time. It was also decided that we go for using the Ne21 beam next.

3. Sabine's practice talk:
SE presented the talk prepared for the NPDC conference in Debrecen/Hungary.
It was agreed on, that all results for the resonances in 21Na(p,g) at E_cm
212 and 822 keV should be classified "preliminary".

4. business arising:
DAH: According to the "final_1" version, the DRAGON is formally scheduled
for 21Ne beam 2-9 Oct. This beam time will be used to study the broader
(G=4keV) resonance at E_cm = 733 keV in 21Ne(p,g) and to study
irregularities in the yield of the 501 keV resonance, that were observed
during the ion chamber runs in August this year.
JDA: Barry Davids will visit TRIUMF this week. A meeting with him and the
DRAGON group will be scheduled presumably for Thursday.
Concerns regarding the measurement of 15O(a,g) at E_cm = 504 keV were
postponed to an extra meeting, that will be scheduled soon. To be discussed
are the following items: minimum beam intensity required, possibilities of
optimization of the BGOs like further fragmentation, count rates expected,
and beam suppression needed. AO pointed out, that the subject does require
some preparation and a meeting within the next week would exclude some
people who would be interested, but gone on trips.
DO presented pictures taken with a CCD camera looking at the beam in the H2
gas. The pictures show a round purple spot that could clearly be related to
the presence of the ion beam. An online camera displayed in the control room
could help tuning in the future. A test set-up will be installed with some
borrowed equipment. SE will check with the Bochum group, what colours were
observed there.
The ISAC operators asked to be informed, when people are leaving the
counting room for a longer period during the beam time or finish their
shifts early.
DAH reported that John Mackenzie installed a new hall probe in the Prague
magnet, that will cover the full range of interest. In doing so it turned
out, that the accuracy of the probe tested on the bench to better than 0.1%,
was off by 4% when installed in the Prague magnet. The probe sits in a
teflon box, which presumably got misaligned. That could explain the
disagreement between the Prague magnet energy calibration and the DRAGON
measurements observed for some of the runs.
5. job list:
DO: The broken cryo pumps will be shipped back today after Tommy Inglis
finished some tests.
PM: A proper walk way around the DRAGON will be mounted in short time.
AO: Miguel Olivo should be asked to pursue further conditioning of the ED
units.
JDA will focus on finishing the facility paper