Project: "Development of a GOOSY-PAW Successor System"
Minutes of the 8th Meeting on August 27, 1998
Participants: R. Barth, W. Brüchle, H. Essel, R. Holzmann, C.
Kozhuharov, N. Kurz, M. Richter, K. Schmidt, E. Stiel, H. Winter
Distribution: H. Brand, P. Braun-Munzinger, S. Glückert, H. Göringer,
N. Herrmann, S. Hofmann, M. Kaspar, H. J. Kluge, P. Koczon, W. Koenig, U. Krause, U.
Lynen, V. Metag, W.F.J. Müller, G. Münzenberg, V. Schaa, C. Scheidenberger, C. Schlegel,
K.H. Schmidt, H. J. Specht, R. Steiner, K. Sümmerer, G. Bollen, Th. Nilsson, H. Simon, R.
Fox, K. Suzuki
1. E. Stiel, W. Brüchle: Nuclear Chemistry Experiments
Different experimental set-ups have been described:
- Surrounded by detectors is a stack of 8 identical targets inline the beam axis each with
a backing impervious to fission products facing the beam. The prompt fission fragments can
leave the targets only in forward direction defining an angle region (open area) for each
target where the fragments can hit the surrounding detectors. Fragments from delayed
fission will come from locations outside the targets, i.e. some may also be seen in a
"shadow" area. The detectors are multi-wire proportional chambers, 1 start and 2
stop counters on each side parallel to the beam and the target stack. The detectors give
dE, time, and position information for reconstruction of each fragment's trajectory. The v
- dE information selects fission products from background signals. The correlation of a
fragments and its source target (one of eight) is done by polygon-conditions on the target
area together with window-conditions in the beam direction (defining a volume). In
addition, only coincidences between fragments found in the open area with those found in
the shadow area are selected.
- a gas jet system transporting irradiated material out of the target area continuously
needs to be set and controlled during the irradiation
- a rotating wheel multi-detector analyzer (ROMA) with currently 64 sectors (to be
expanded to over 100) transports products of chemical separations. In steps of several,
fixed seconds the wheel moves the collected activity between 8 pairs of PIPS detectors
measuring the time dependent Alpha and fission radiation. The wheel stepping is controlled
by a standalone PC. Both, Alpha and fission events are acquired by the MBS system and
analyzed by GOOSY. In addition, the Alpha events are accumulated on a multi-channel
analyzer. In case of an implantation of a Alpha-decay daughter in a detector, the wheel
will be rotated just half a step, i.e. the probes are outside the detectors for a certain
time. This will reduce the background to find grand-daughter Alphas for this decay. The
detection of such an event is currently done by a discriminator in the Alpha detector line
triggering the stepping PC. This method should be replaced by a more detailed analysis in
the data acquisition processor.
Following requests on GO4 have been expressed:
- multi-indexed spectra names
- interactive histogramming under dynamic conditions of all input parameters and new
parameters produced by mathematical and logical combinations of parameters.
- polygon conditions
- analysis of time correlations between events (Alpha ray mother-daughter relations) in a
time scale of ms to min.
- real-time analysis in the data acquisition processor connected with set-up control
- Gamma line search programs
- Gamma line data base
- interactive graphical analysis of gamma-ray coincidence data (may be the software
package RadWare http://radware.phy.ornl.gov is
suitable. It is available at GSI on several platforms)
- a sort of trending storage of data, i.e. keeping events in a ring buffer for a given
time window. This is needed for finding long-time correlations.
- portable data acquisition and analysis systems including front-end, workstation or PC,
and storage drives for experiments outside GSI
2. Next meetings:
Monday, September 28, 1998, 14:00
R. Holzmann: HADES Analysis
Thursday, October 1, 1998, 14:00
Ilse Koenig: Use of Oracle Data Base in HADES Analysis
Thursday, October 8, 1998, 14:00
K. Schmidt: Experiments at the FRS
Tuesday, October 20, 1998, 09:30, Seminarraum Theorie
K. Rehlich, DESY: DOOCS, an Object-Oriented Control System for TTF (TESLA Test Facility)
M. Richter, August 27, 1998