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GSI-ACCELERATORS-01 GSI SCIENTIFIC REPORT 2009
128
SIS Experiments
The heavy ion synchrotron delivered beams to 26 fixed
target experiments and to 7 experiments at the ESR. In
total 4321 hours of target time have been achieved. The
summary is given in Table 3.
In 2009 the main SIS user was FOPI. About 1250 hours
of beam time were delivered to this experiment. The target
time for ESR (direct beam and beam via FRS) increased
to 1097 hours. For about 482 hours beam was
delivered to the FRS.
Table 3: Beam delivered to SIS/ESR experiments
Time Ratio
Target time for experiments 4321 h 73,5%
Time for retuning 39 h 0,7%
Accelerator setup 650 h 11,1%
Ion source service 100 h 1,7%
Unscheduled down time 769 h 13,1%
Total beam time 5879 h 100%
Accelerator operation
Figure 2 shows the total beam time for all accelerated
isotopes during 2009. Over the year 18 different isotopes
have been accelerated. The rare isotopes ( 6 Li, 7 Li, 34 S,
48 Ca, 54 Cr) were produced by the ECR ion source, which
has been operated for 4757 h. Besides Li these beams
were mainly provided to UNILAC experiments. The Penning
ion source was mainly used for 96 Ru, 58 Ni and 197 Au
(in total 2632 hours of operation). The high-current ion
source operation lasted for 2725 hours. Especially 40 Ar
and proton beams were delivered from the MUCIS ion
source. 238 U was accelerated from the MEVVA ion source
for 533 hours.
Table 4: Statistics of all unscheduled down time events
Down
time
No. of
events
Power supplies 339 h 303
Vacuum and structures 159 h 111
Beam diagnostics 34 h 31
Operation 37 h 37
Safety-/ Interlock system 177 h 59
Ion Sources 103 h 71
RF system 287 h 465
Controls 94 h 58
Infrastructure 69 h 27
Others / 55 h 51
Total of unscheduled
down time
1354 h 1189
In Table 4 all unscheduled down time events are shown
in more detail. Compared to 2008 about 200 hours less of
down time events were recorded due to a decrease of
breakdowns of power supplies and ion sources.
An earth leak of the main feed-in of the SIS power supplies
caused a break of two days for SIS operation. The
renewed control of the radiation safety system of
SIS/ESR caused a lot of interruption in the first block.
This system was upgraded and runs very reliably meanwhile.
During commissioning for the forth block the
breakdown of one drift tube cooling threatened a stop of
the operation. However, a special mode of low duty cycle
operation was tested successfully. This mode allowed
standard beam conditions for SIS injection and the operation
could be continued. For the UNILAC experiments
with energies above 5.9MeV/u the duty cycle needed to
be restricted. The drift tube was replaced during the subsequent
shutdown.
isotopes
1H
6Li
7Li
12C
34S
40Ar
48Ca
54Cr
56Fe
58Ni
96Ru
122Sn
124Sn
129Xe
136XE
181Ta
197Au
238U
0 500 1000 1500 2000 2500
operation (h)
Figure 2: Total beam time for the different ion species
For accelerator experiments at the UNILAC 144 hours,
at SIS 301 hours, and at ESR 95 hours beam were delivered,
which is for SIS an increase by a factor of three
compared to last year.
References
[1] OLOG GSI operation logbook
[2] Report of beam time coordinator, this report