CERN Accelerating science

Internal Note
Report number	CERN-ACC-NOTE-2020-0060
Title	Dynamic simulations and transient management of the HL-LHC cryogenic system during beam operation
Author(s)	Bradu, Benjamin (CERN)
Corporate author(s)	CERN. Geneva. ATS Department
Publication	2020
Imprint	16 Nov 2020
Number of pages	36
Subject category	Accelerators and Storage Rings
Accelerator/Facility, Experiment	CERN LHC
Project	CERN HL-LHC
Technology	Cryogenics
Processes	Operations Management ; Computed Aided Engineering
Keywords	CERN HL-LHC ; HiLumi LHC ; Cryogenics ; Systems Engineering
Abstract	This paper presents a set of dynamic simulations performed on the future High Luminosity Large Hadron Collider (HL-LHC) cryogenic system. The objectives of these simulations are to provide main pressure, temperature and flow transients over the cryogenic distribution system around the collision points 1 and 5 during the forecast beam operation. These simulations have to be used to help the different cryogenic system specifications where strong dynamic heat loads will induce significant transient modes. This dynamic model embeds the 1.9 K cooling loops (inner triplets, D1-D2 magnets and crab cavities), the beam screen cooling loops between 60 K and 80 K or between 4.5 K and 20 K and the cryogenic distribution line. As result, a series of recommendations is given to mitigate sufficiently the transients such as the use of significant preloading of magnets in association with feed-forward controls.
Submitted by	[email protected]