|
Author(s)
|
Ferracin, P (LBL, Berkeley) ; Ambrosio, G (Fermilab) ; Anerella, M (Brookhaven) ; Bingham, B (LBL, Berkeley) ; Bossert, R (Fermilab) ; Caspi, S (LBL, Berkeley) ; Cheng, D W (LBL, Berkeley) ; Chlachidze, G (Fermilab) ; Felice, H (LBL, Berkeley) ; Hafalia, A R (LBL, Berkeley) ; Mumper, W (Fermilab) ; Nobrega, F (Fermilab) ; Prestemon, S (LBL, Berkeley) ; Sabbi, G L (LBL, Berkeley) ; Schmalzle, J (Brookhaven) ; Sylvester, C (Fermilab) ; Tartaglia, M (Fermilab) ; Wanderer, P (Brookhaven) ; Zlobin, A V (Fermilab) |
|
Abstract
| As part of the effort towards the development of Nb$_3$Sn magnets for future LHC luminosity upgrades, the LHC Accelerator Research Program (LARP) has fabricated and tested the quadrupole magnet LQS01. The magnet implements 3.4 m long Nb$_3$Sn coils contained in a support structure characterized by an external aluminum shell segmented in four sections. The room temperature pre-load of the structure is obtained by shimming load keys through bladders, pressurized during the loading operations and removed before cool-down. Temperature compensated strain gauges, mounted on structure components and coil poles, monitor the magnet's mechanical behavior during assembly, cool-down and, excitation. During the first test, LQS01 reached the target gradient of 200 T/m; the gauge data indicated that the aluminum shell was pre-tensioned to the target value estimated by numerical models, but a lack of pre-load was measured in the coil inner layer during ramping. As a result, the test was interrupted and the magnet disassembled, and inspected. A second test (LQS01b) was then carried out following a re-loading of the magnet. The paper reports on the strain gauge results of the first test and the analysis performed to identify corrective actions to improve the coil pre-stress distribution. The mechanical performance of the magnet during the second cool-down and test is then presented and discussed. |