The P42 enigma

1 DECEMBER, 2022 | By Lau Gatignon

Three new experiments submitted LOI’s to the SPSC for using ECN3 after LS3: HIKE, SHADOWS and SHIP.
All request much higher beam intensities than now: 3 x10¹² → 2 to 4 x10¹³ppp.

The difficulties to commission the P42 and K12 lines for NA62 underlined the essential role of beam instrumentation, both in P42 and TT20. Some urgent improvements have been made already, more yet to come.

Intense studies have been started in a dedicated PBC ECN3 task force (experiment agnostic so far) and the experiments, together with the BDF and CBWG working groups, have looked at their specific needs.

One potential bottleneck is due to radiation in various places, e.g. in the ramp from B892 to EHN1 and at the bridge on the road to B911. Thanks to these studies (collimation, reduction of material, shielding, etc) the dose levels have been reduced already by an order of magnitude (and even more in some places). With these improvements the intensity increase seems to have become feasible from this point of view,

In parallel a lot of work is on-going on making the equipment compatible with the increased intensities. This includes primary targets, beam dumps, machine protection and shielding.

The future use of ECN3 will be decided along the following timeline:

Justification of intensity upgrade (experiment agnostic) by March 2023 in the framework of the 2023 MTP
The final choice of experiment from the end of 2023

Already during the 2022 run several
improvements could be made:

Relevant beam instrumentation has been made operational
Shielding was improved and fences were installed at the ramp to EHN1
The collimation was improved with a view to radiation protection
Machine protection was speeded up and additional interlocks were implemented to protect NA62 equipment

In parallel, many studies are ongoing to be ready in time for the decision to upgrade for higher intensity and for the implementation of the experiment(s) chosen in the end.