Vertical cryostats
We have five vertical cryostats, one of them (Cluster D) in a pit below ground, with a dedicated 30 kA and two dedicated 2 kA power converters, and the other four (Siegtal, Diode, HFM and Long) in another location, sharing a 20 kA, a 10 kA and two 600 A power converters. The main characteristics of the five cryostats are given in the table below. Information about services and systems in the test area can be found here.
| Cryostat | Cluster D | Siegtal | Diode | HFM | Long |
| Useful diameter [m] | 0.85 | 0.75 | 0.45 | 1.45 | 0.55 |
| Useful depth [m] | 5.34 | 1.25 | 1.30 | 2.24 | 3.35 |
| Operation Temperature [K] | 1.9, 4.5 | 1.9, 4.5 | 4.5 — 80 | 1.9, 4.5 4.5 — 80 | 1.9, 4.5 |
| Main power converter | 30 kA with dump (max 1 kV) | 20 kA with dump (max 1 kV) | |||
| Auxiliary power converter | 2 x 2kA with dump (max 1 kV) | 2 x 600 A with dump (max 500 V) 10 kA with dump (max 500 V) | |||
Cluster D
Cluster D is the deepest cryostat we have, at 5.34 m of useful depth. It is the only test station with a 30 kA power converter available. We have two inserts for Cluster D, one of which can be equipped with anticryostats, and is expected to be fully commissioned by mid 2026. The main drawings for this test station are listed below:
- Cryostat with insert assembly: https://plm.cern.ch/p/CAD/cdr:CRNQLKJH0001:AA.00
- Cryostat alone: https://plm.cern.ch/p/CAD/number:ST0676943_01:AA.00
- Insert 1 (incompatible with anticryostats): https://plm.cern.ch/p/CAD/cdr:CRNQLKJH0238:–.00
- Insert 2 (compatible with anticryosats): https://plm.cern.ch/p/CAD/cdr:CRNQLKJH0275:–.01
Siegtal
Siegtal is one of the smallest cryostats we have. It is typically used for small LHC correctors (MCBY, MCBC, MSCB…), for HL-LHC high order correctors (MC_XF), and for several R&D magnets. The main drawings for this test station are listed below:
- Cryostat (draft drawing): https://plm.cern.ch/p/CAD/number:ST0853911_01:AA.00
- Insert: https://plm.cern.ch/p/CAD/number:ST0561631_01:AA.00
- Example integration of a magnet in the cryostat: https://plm.cern.ch/p/Part/cdr:CRNMRDFUSS0014:1.01
Diode/CTV
The Diode cryostat was originally designed for test of LHC diode stacks and current leads. By using a satellite cryostat that can provide helium gas at variable temperatures, the Diode cryostat can also test HTS magnets at variable temperatures, in the CTV (Cryostat à Température Variable) configuration. The main drawings for this test station are listed below:
- Insert for diodes test: https://plm.cern.ch/p/Part/cdr:LHCQDTE_0001:1.01
- Insert for 600 A current leads test: https://plm.cern.ch/p/Part/cdr:LHCQDTB_0001:3.02
- Insert for 6 kA current leads test: https://plm.cern.ch/p/Part/cdr:LHCQDTC_0001:2.01
- Insert for 13 kA current leads test: https://plm.cern.ch/p/Part/number:ST0351985:1.01
- Example integration of Feather2: https://plm.cern.ch/p/Part/cdr:HFMF2HTS0079:1.01
HFM
The HFM cryostat is the widest we have, at close to 1.5 m in diameter. It was originally designed to test the Fresca2 magnet, and the Feather2 as an insert to the Fresca2 magnet. In 2023-2024 a modification was done to the cryogenic infrastructure between Diode and HFM, to allow Diode’s satellite cryostat to feed helium gas at variable temperature in HFM. As of October 2025, a new insert is under design to be able to test magnets cooled with forced flow helium in a vacuum environment. The main drawings for this test station are listed below:
- Cryostat: https://plm.cern.ch/p/CAD/cdr:CRNQLKJE0494:–.00
- Insert 1 (bath-cooled magnet): https://plm.cern.ch/p/CAD/cdr:CRNQLKJE0274:AB.00
- Insert 2 (flow-cooled magnet): in preparation
Long
The Long cryostat was the longest cryostat we have until the commissioning of Cluster D. In this cryostat, we tested all the LHC main quadrupole magnets in stand-alone configuration and several of the Nb3Sn 11 T short models, among others. The main drawings for this test station are listed below: