1. Technical news - GPS
a. On GPS, until Thursday morning, measurements with the LIST target-ion source unit took place.
b. Collection with Fr beam on Friday on GLM.
c. On Tuesday target changed to LaC2 #489. During this procedure the TA robot got stacked – after recalibrating the position the problem got solved .
d. When starting the Cooling system the system failed for unknown reasons thus impacting in the HRS cooling and switching off the transformer. The emergency reservoir went into play but did not last long. Reason: small flux of incoming water and sprinkling water on the back wall of the RILIS hut. Fixed.
2. Technical news – HRS
a. Target #487 UC2-C W surface. On use for Po beams to REX-MINIBALL
b. FC490 found leaking, presently blocked in the ‘out’ position. Intervention scheduled on Thursday morning, replacement by FC390 is considered. A possible reason might be the wear of the material, thus a counter registering the number of in and out moves will be installed. A new FC is going to be ordered with an expected delivery time on the order of several months.
c. HRS+RFQ Cooler transmission > 80% for 238U at 30 KV
d. Investigation of Coulomb excitation of Po isotopes at Miniball.
3. Technical news - REX/RILIS
a. REX: set in a very short time, the transmission achieved for 196-206Po was 80% (from the trap to the MB site), 90% just in the LINAC. All mass changes have been done by the user.
b. Monday: INCA test in the control room
c. A water leak in the RFQ amplifier was found on Wednesday evening, followed by a fast repair (thanks to the RF, CV and main workshop teams the run could start on time).
d. EBIS control– problem with steering of electrons, will be farther investigated.
e. RILIS: with the GPS target a narrow band mode was used in IS456 in order to investigate the hyperfine structure of 217Po, 218Po and 219Po. A 0.2 counts/s rate for 221Po was observed. For the MB run the broad mode was used at the HRS.
f. LIST was tested with UCx targets in two modes. In the ion guide mode it could not be used due to the space charge effects in the over loaded hot cavity. Fortunately in the LIST mode worked very well with more than 3 orders of magnitude suppression of ions originating in the hot cavity . Unexpected feature of LIST was the observation of a beam of 216At (T1/2 = 300 microsec) and 217Rn(T1/2 = 540 microsec), shortest lived ISOLDE beams. Produced as decay products of 220Fr and 221Ra.
4. Other technical news:
a. The CV team found the source of dust in the RF room, it was due to a fan belt. New filters have been installed.
5. Physics and schedule
a. IS456 laser spectroscopy of Po isotopes, use of windmill setup. An investigation of possible suppression of the release of surface ionised Fr from the Ta was performed, possible for 217, 218Po, but not for 211, 212Po (coating on the rod of the RF structure upstream the target). Some measurements done also for lighter masses (Na, K, Al) show a suppression on the level of 1e3 or more.
b. MB: studies of shape coexistence around Z=82. Investigated: 198,200,200Po isotopes. Due to the use of laser ionization a two times higher production observed comparing to the last experiment in 2009.
c. The RILIS group was comparing the beam from the GPS LIST target and HRS standard target.
d. LINAC is available for tests.
6. Safety
a. First level radiation alarm triggered twice by PAXY08 monitor (threshold set to 3uSv/h, device located between EBIS and the separator). After decreasing the p current a fast recovery has been observed.
b. COLLAPS and CRIS got a safety clearance
c. The balloon got emptied on Friday morning
7. AOB
a. LN2 delivery did not happen on Tuesday instead came on Wednesday morning, creating a severe amount of stress especially for the MB community. Magda is in contact with the purchase office.
b. Please keep in mind that a minimum order of LN2 is 0.25 m3. If ordered less the supplier will charge this amount anyhow.
c. In case of recycling of the CERN computers please contact the Help Desk in order to erase the hard-drive by a trained technician. Afterwards, either consider sending a request for removal of the device or bring it to your favourite electronic thrash bin by yourself.
d. The new bulletin got released including articles about ISOLDE http://cdsweb.cern.ch/journal/CERNBulletin/2012/38/News%20Articles/?ln=en
e. The meeting was followed by the seminar of Paul Finlay “Superallowed Fermi Beta Decay Studies at TRIUMF-ISAC” https://indico.cern.ch/conferenceDisplay.py?confId=208546.
f. Next week Pauline Ascher will speak about “Studies on an exotic decay mode: the two-proton radioactivity”.
Minutes by jk