NA61/SHINE requested ion beams in Run 3 for three physics programs:
- Pb beam for open charm measurements (top priority)
https://cds.cern.ch/record/2799311?ln=en
The formal status of the request:
four weeks of Pb at 150A GeV/c in 2023 recommended by SPSC in 2022
- Pb for the nuclear fragmentation cross-section measurements for cosmic-ray physics
https://cds.cern.ch/record/2309890
The formal status of the request:
SPSC is looking forward to further measurements (minutes of the 2019 meeting)
- O beam for the study of the onset of the QGP fireball and fragmentation studies
https://cds.cern.ch/record/2810689?ln=en
The formal status of the request:
no response from SPSC
The recent uncertainties are briefly summarized below:
A) The LHC malfunctioning may impact the 2023 Pb run. The new injector schedule will be presented on September 1st. The Pb beam time allocated to NA61/SHINE will likely remain unchanged (four weeks) (private communication from BE colleagues).
B) Loosing two months of LHC protons in 2023 may cancel the Pb run in 2024, primarily for LHC and possibly for us. This should be taken into account in our planning. We will probably have more information on September 1st.
C) At the September SPSC, Rende will present two versions of the 2024 SPS schedule. One of them will include several days of oxygen in SPS after TS. Advocating for this version without reducing the 2024 Pb beam time would be important.
During several days of the oxygen beam, we could test the water target for the post-LS3 O+O running (the corresponding addendum is submitted to the September SPSC - https://cds.cern.ch/record/2867952?ln=en) and take the CR fragmentation data. This could be a several-day-long test run, which does not require the SPSC recommendation.
D) In the case of cancelling the Pb run 2024, we should request compensation for the lost ion beam time by having a four-week-long O beam time in 2024.
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Update from Rende on 24.08.2023
Dear Marek,
The present plan is to have a very brief period (several days) with Oxygen ion in the LHC (possibly also in the SPS if there is an interest and if it is compatible with the proton requests) in June 2024 and then to be ready for the Pb ion period in the LHC and the SPS-NA for the end of the 2024 run.
Following the issue in the LHC we may have a slightly longer LHC Pb ion run this year and discussions will start on the length of the ion run in 2024. However, to a certain extend the LHC Pb ion run is independent from the SPS-NA Pb ion run. Even if for the LHC we would decide not to run Pb ion in the 2024 it does not mean we will not run Pb ions for the SPS-NA. Four weeks sound reasonable and I do not expect issues for that, even if the LHC would run shorter or not at all with Pb ions in 2024.
I therefore can only recommend to clearly state your beam request (Pb ions and Oxygen ions) to the SPSC for discussion and recommendation to the RB.
With kind regards,
Rende
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From Urs
