April 2024 : a great project for a great magnet.
GrAHal is happy to present its collaborative project with CAPP. It aims at searching the DM axion in the 1-3 micro-eV (725-240 MHz) range at « DFSZ sensitivity ». Using Grenoble’s great magnet of course ! Details were just published here.
July 2023 : great news from the LNCMI new hybrid magnet !
On the 19th of july, the superconducting outsert of the new hybrid magnet in LNCMI was powered up to its nominal stored energy !
This is a major step in the comissioning of this unique magnetic field source … and great news for GrAHal which plans to hunt DM axions with it.
Recall the new hybrid magnet will operate in several magnetic field/bore volume configurations, combining a large superconducting outsert and various resistive inserts.
For its second cooling run, the outsert reached its nominal low temperature: 1.85 K . It took over 2 month to cool its more than 20 tons of metal. Recall its dimensions are 800mm inner bore diameter and 1.4m height !
Then several powering cycles were applied, and the nominal stored energy was successfully reached on july the 19th, producing 8.53 Tesla in the center of the coil.
After a short pause in august the commissioning will continue, the resistive inserts entering into action.
October 2022 : GrAHal gets funded by the ANR.
This year’s application was successful and GrAHal gets a funding from the ANR, the french funding agency for science. Earning a bit more than 800 kEuros for 2023-2026, the collaboration will hire PhD students and postdocs, and develop a state of the art He3/He4 dilution refrigerated haloscope working in a 14T magnetic field, using our best TWPA amplifiers designed to work in the 6-10 GHz frequency window. R&D will be conducted for the deployment of GrAHal in the new LNCMI hybrid magnet. The theorists of the collaboration will pursue work on axion and ALPs physics, and explore the potentialities of haloscopes for high frequency gravitational wave search.
Summer-fall 2022 : the new hybrid magnet of LNCMI has started its commissioning.
A longstanding project, the new hybrid magnet of LNCMI (the french high magnetic field facility) has entered its commissioning period this summer. The cooling of the large (800mm bore !) superconducting outsert is going on, with a first transition to the superconducting state early october. Progressive current tests will be performed until the end of the year, and the whole facility, including the resistive inserts, will be commissioned in 2023, when a first run at 43 Teslas in programmed.
October 2021 : GrAHal note on arXiv.
A short note describing the GrAHal project and its first path finding run is now on arXiv.
September 2021 : hybrid magnet assembly status
The Grenoble hybrid magnet using resistive and superconducting technologies will be a modular platform, delivering various DC high magnetic field and volume configurations for the scientific community, ranging from 43 T in 34 mm diameter (possibly 45-46 T in the future) down to 9 T in 800 mm diameter when the superconducting outsert magnet is used alone.
Important steps were taken in 2020 and 2021. The large bore superconducting coil was delivered and successfully inserted inside the He vessel, which was a very delicate maneuver.
The cryogenic satellite producing the cooling fluid (pressurized superfluid He) was successfully commissioned, and the cryogenic line connecting the cryogenic satellite to the magnet cryostat is being assembled. As for the resistive inserts, the two outer Bitter stacks are ready for installation and the innermost polyhelix part is being machined.
The superconducting magnet cooldown is expected to start beginning of 2022.
July 2021 : first haloscope prototype operation
During Quentin Basto’s graduate student intership, GrAHal’s first haloscope protype was tested, searching for axions near 6 GHz. Operating at 4.5 K in a 14 T magnetic field, its present sensitivity allows to probe axion-diphoton coupling constants down to 20 times the KSVZ benchmark. Its future upgrades will permit to approach the KSVZ limit.