0. Comments to the minutes of the ISOLDE Physics Group Meeting of the 03.10.2012:
a. Point 1b: Guilherme: "The abovementioned effect was neither observed in front of GLM nor in the focal plane of the magnet." should read: "The above mentioned effect was observed both in front of GLM AND in the focal plane of the magnet." (JMC)
b. Point 2g: input from Miguel:
The turbopump in the RFQ did not break. There was a problem with the controller that for this turbopump is integrated inside of the pump itself. This problem was creating an alarm on the PVSS (vacuum system application). According to the system the turbopump was not reaching its nominal speed and after some minutes the control system was switching it off.
In collaboration with the vacuum expert we decided to disable the alarm so the pump could run. An intervention to check if the problem is real or just a wrong signal will be scheduled by the vacuum team.
This incident could be related with the transmission problem we had at the RFQ but it is something that remains unclear for me until the turbopump is checked.
1. Technical news - GPS
a. UC target for GLM and GHM (Ag beam), problems with the HV which was tripping at the beginning, changed from 50kV to 30kV.
b. p-scan done on Wednesday by using a Faraday cup – no beam visible on the tape station. Mass factor of the magnet had to be changed by 4 cm, only then the expected activity could be observed on the tape station. The problem is not fully understood: it is most probably due to several masses visible in the range of interest, as this target has already seen protons.
c. The Faraday cup FC490 on GPS was not coming out. The BI team applied some grease on the piston of YGPS.FC490 and increased the pressure in the gas line. Problem fixed.
d. Fluctuation of the beam has been observed.
e. On Friday, switch of GLM beam gate broken. To be repaired by Pascal. For the moment a work around applied by putting the beam gate in remote and run it from the timing module in the same rack as the beam gate switches.
f. Saturday morning beam stopped, cooling of the target.
g. Monday change of the target to UC, the shutter valve on the target could not be fully closed, perhaps related to the extraction electrode which possibly does not move back.
h. Old target reheated, Tuesday morning checks done by moving the extraction electrode – no influence of the beam position observed, suggesting that in reality the extraction electrode is not moving. Also, the HV drops when trying to close the valve. Final test scheduled on Monday (added after the meeting: the intervention might be postponed), an ALARA3 procedure involving the GPS camera is being prepared. If the test confirms that the electrode is stuck, GPS will not be operational this year. Spokespersons of GPS runs informed of this possibility.
2. Technical news – HRS
a. Tuesday: Beam to ISOLTRAP.
b. Target heating dropped, switched to local mode.
c. Communication lost twice with MAG60, Emiliano called. Reset of crate G64 done with users on the phone. For possible future problems: users who are familiar with the procedure please inform the operator and follow his instructions on the phone.
d. RFQ was not bunching the beam, the optical fibre receiver broken. Once repaired, users could still not bunch the beam due to the RFQ "0" settings, which were chopping the beam. After changing to "normal" settings, the bunched beam was available again. Cooler settings to be followed by Magda, Tim, CRIS and COLLAPS teams.
e. The line of the target dropped, problems with PLCs. Presently, both target and the line remain in the local mode. This will be changed this week if necessary for LA1+ISOLTRAP run. Otherwise, to be repaired before the next target comes online.
f. Tuesday afternoon, preparation for LA1 (stable beam tuning + RILIS optimising on Au), afterwards the windmill experiment took the beam in order to investigate n-deficient Au isotopes (until Wednesday morning).
g. Wednesday: Beam to ISOLTRAP and LA1 till 9h00, the cooler efficiency for the beam sent to ISOLTRAP will be checked on Wednesday evening.
Due to GPS problems, GPS REX run is moved to HRS and REX setup will take place during daytime on Wednesday, Thursday, and Friday. The HRS schedule can be minimally affected.
h. CRIS users reported that RFQ was not bunching the beam (only chopping). After few investigations, it came out that the extraction electrode A was not pulsed and the optical fibre receiver was found broken. Once repaired users could still not bunch the beam due to the RFQ "0" settings. After changing to "normal" settings, the bunched beam was available again.
3. Technical news - REX and RILIS
a. REX: problem with one FC. Setting up with an old HRS target, in order to recover at least partly the physics programme affected by problems with the GPS (Miniball experiments). The HRS schedule will not be affected.
b. RILIS: good run on At and Ag, starting setting up for Au. Laser beam was provided for CRIS.
4. Other technical news
a. Water in the RF room, taken out by the fire brigade. The repair of the roof is scheduled.
b. CRIS team found the optimal cooler setting at 40kV (running in bunching mode).
c. Successful migration to INCA controls done on Monday.
5. Physics and schedule
a. Successful collections running GHM and GLM in parallel. Collections for solid-state groups from Portugal and Germany. Biophysics run achieved at least the minimum programme.
b. CRIS: very good efficiency, over 10 Fr isotopes studied in the mass range 202-231. A compatibility of the observed rates with the values registered by the decay station was demonstrated.
c. The LA1 team focused on Au isotopes, namely 177Au, 178Au, 180Au. The experiment seems to be successful.
6. AOB
a. The meeting was followed by the seminar of Alexander Gottberg: "Recent Target and Ion Source Developments at ISOLDE”.
b. No seminar next week due to EURISOL meeting. In two weeks Tommi Eronen will speak about “Mass spectrometry and decay spectroscopy around 132Sn”.
c. Based on the question from Susanne, it was confirmed that outside working hours we should ONLY call the main operator in charge and NOT the ‘backup’ person.
Minutes by jk