13 September 2017
Minutes of the ISOLDE Physics Group Meeting, 13/09/2017
Technical news
• GPS
- The week was shared between collections for medical purposes/bio physics and beam development with RILIS/ISOLTRAP. Target # 565 Ta performed well.
- Last week’s operation was smooth although the problem with switching off of different electrostatic elements (CA0) persisted. On a couple of occasions this could be correlated to a vacuum glitch but otherwise their powering off seemed to be random.
- On Wednesday evening the power in the electrical cupboard with the GPS/HRS power supplies tripped due to an imbalanced distribution.
- The lack of beam diagnostics in the vertical plane makes setting up the machine difficult.
- Target #611 UC2-C was installed on Monday for 94Rb beam to Miniball. During the installation there was a problem with the robot which picked up the target in a wrong way, requiring manual intervention.
- There will be a technical stop on 18th and 19th September.
•
HRS
- Ni beams were available for COLLAPS from the end of the week. Earlier in the week, stable surface ionized beams could be used for setting up.
- The power supply of QP330 was broken and exchanged.
- On Tuesday night there was a problem with the transmission through the cooler which suddenly dropped and which could only be restored by changing the high voltage on the cooler by 10V. The same problem occurred later in the night, but was self-restored after few minutes. This problem is not understood but was not seen later on in the run. o When putting protons on target, note that it is not possible to send 0A to the last dipoles in the BTY line as in reality this results in 40 A being sent. The solution is to send 0.01A.
- At LA2, the plan was to install prototype scanners which should replace the wire scanners throughout ISOLDE. Unfortunately, the scanners were 1 mm too big and the installation was postponed.
• REX/HIE ISOLDE
- On Tuesday, there was an intervention to investigate the water flow meter problems which were experienced in the last weeks.
- For the first time, all superconducting cavities will be running together for the run on 94Rb23+.
- With a beam energy of 6.3 MeV/u, it will be the highest energy beam at which HIE-ISOLDE has operated so far.
•
RILIS
- It has been a busy week for RILIS providing Dy schemes for collections in the night while alternating between Sc, Se and Ti schemes for TISD during the day. Although difficulties in producing and measuring Ti and Se beams were encountered, the Sc beams were quite successful with measurements being done on 46-50Sc.
- Due to a delay in the preparation for collections on Wednesday night and a misunderstanding in the planning, the switchover to Ni could not be done until Thursday evening. Due to a lack of time, the Ni scheme, using the green laser, was not optimized. On Saturday, the green laser was swapped with the TiSa laser and, with some fine tuning by B. Marsh, a clear improvement of a factor of 10 could be gained.
- The two photon spectroscopy initially planned had to be postponed due to the inability to operate the designated TiSa laser in the RILIS lab.
Physics
• Collections
for
medical
purposes
and
biophysics
went
well.
– The samples are shipped to various institutes, we will still have to wait a couple of weeks for the outcome.
– The new chamber and procedures for collections worked well. This promises an active medical program next year.
– 172Lu and 138Nd were implanted in solutions and foils for PAC measurements for biophysics. In addition 160Ho and 149Gd were also collected, but in a more exploratory manner to test their suitability for future experiments.
• The
COLLAPS
run
on
Ni
experienced
problems
due
to
low
yields.
– The plan was to start with protons on the neutron convertor to study neutron-rich Ni, in particular to remeasure 70Ni and extend the data to 69,71,72Ni. Unfortunately, yields were too low so it was decided to put protons on target to study neutron-deficient 56Ni and 57Ni and to improve the yields of the neutron-rich (with the disadvantage of greatly increasing the Ga contamination).
– While there was a 20 fA RILIS ON/OFF effect on 56Ni during the weekend, no resonance in the hyperfine spectrum could be observed. A check of the beam composition on mass 56 was performed on Tuesday by ISOLTRAP revealing only very little 56Ni (few 100/s), but at that time no RILIS/ON effect was seen anymore.
– The results on 70Ni still need a proper analysis before anything can be concluded. Nevertheless nothing more exotic could even be attempted with these yields.
• Next
week
a
miniball
run
with
94Rb
will
be
preformed
to
study
excited
states
around
212Pb.
– It is expected that using multinucleon transfer reactions 16+ isomers in Mercury isotopes can be populated which weren’t seen in the fragmentation reactions at GSI before.
– It is expected that also a low-lying 3- octupole deformed state in 210Hg will be populated.
• Stable
beams
should
be
delivered
to
VITO
on
Tuesday
for
the
beta-NMR
run
using
Na
in
liquid
samples.
Safety
• RP
and
EP
safety
were
very
happy
with
how
the
collections
went.
The
use
of
the
new,
well-shielded
collection
chamber
resulted
in
a
total
dose
of
only
14
uSv
throughout
the
run.
Visits
• There
will
be
a
visit
of
a
CERN
intern
on
Thursday
14/09.
People
wanting
to
join
for
a
coffee
afterwards
(~15:00)
are
welcome.
AOB
• All
contaminated
material
was
removed
from
the
old
labs/new
offices
in
building
3.
• From
now
on
until
the
end
of
the
year,
the
MEDICIS
interlocks
will
be
tested
as
preparation
for
next
year.
A
new
VISTAR
with
a
box
for
MEDICIS
will
be
released.
• The
preparation
works
on
the
air
conditioning
in
the
ISOLDE
hall
will
start
this
week.
The
crane
might
be
locked
for
this.
• For
the
European
Researcher’s
Night
on
Friday
29th
September,
Karl
is
still
looking
for
volunteers
to
help
representing
ISOLDE
(part)
of
the
event.
French
speakers
are
particularly
encouraged
to
participate.
Minutes
by
H.
Heylen
Date
2017-09-13