Beschreibung der Beschaffung
The strength of the external magnetic field used for experiments is of major importance in NMR spectroscopy. The strongest field of an NMR magnet commercially available and already installed has a magnitude of ~23,5 Tesla, corresponding to a 1H resonance frequency of ~1,0 GHz. Sensitivity and resolution are getting continuously better with increasing magnetic field strength. It is therefore of high interest to perform NMR experiments at higher magnetic fields and the NMR facility of the FMP needs to be extended by an NMR spectrometer operating at a field of ≥ 28,19 Tesla corresponding to a 1H frequency of ≥ 1,2 GHz. The delivery and installation of the new spectrometer must not take place later than 2023 (preferably earlier) and the vendor must present reference installations of currently active NMR magnets with a field ≥ 23,5 Tesla.
Magnet:
— field strength ≥ 28.19 Tesla,
— operation without continuous electric current entry (i. e. „persistent mode“, not „driven mode“) with drift rate ≤ 45 Hz/h to enable high resolution NMR experiments in liquid and solid state phases,
— limits for the stray field: 5 G radially ≤ 6 m, 5 G axially ≤ 7 m,
— helium evaporation ≤ 300 ml/h, and magnet hold time ≥ 2 months,
— magnet should fit into building with ceiling height of ≤ 8 m,
— equipment for the refilling of the magnet with liquid helium and liquid nitrogen,
— computer control of the level of liquid nitrogen and liquid helium.
Console:
— 4 frequency channels (up to ≥ 1,2 GHz) with a time resolution ≤ 25 ns and the possibility to perform shaped pulses on all channels simultaneously,
— interface for temperature adjustment of the sample in the magnet,
— unit for the application of pulsed field gradients (Z-axis),
— 4 pre-amplifiers (1H, 2H, 2 x nX),
— 2H-lock-system to stabilize the external magnetic field,
— shim-system to homogenize the magnetic field (≥ 35 gradients),
— 4 amplifiers 1H, ≥1 000 W (solid) / ≥ 100 W (liquid)
nX, ≥ 500 W
nX, ≥ 1000 W
2H, ≥ 250 W, including computer-controlled switch between pulse and lock mode.
Probes:
— CP/MAS-probe (HCND), active sample volume ≥ 0,4 l, MAS rotation frequency ≥ 110 kHz,
— CP/MAS-probe (HCND), active sample volume ≥ 1,6 l, MAS rotation frequency ≥ 60 kHz,
— CP/MAS-probe (HCND), active sample volume ≥ 10 l, MAS rotation frequency ≥ 40 kHz,
— CP/MAS-probe (HCND), active sample volume ≥ 30 l, MAS rotation frequency ≥ 20 kHz,
— CP/MAS-probe (HXY), active sample volume ≥ 30 l, MAS rotation frequency ≥ 20 kHz,
— solution-state probe (HCNP),
— MAS pneumatic-unit to maintain rotation ≥ 120 kHz,
— Temperature unit operational for all probe heads, temperature range ≤ 20 °C and ≥ 60 °C, an efficient sample temperature ≤ 15 °C should be maintained at maximum rotation frequency,
— frequency filters for the suppression of unwanted signals for all channels,
— possibility to use a 2H-Lock with all probes.
Additional items:
— spectrometer software license including processing software for the processing of NUS spectra (≥ 10 years duration),
— licenses for processing software for additional workstations including the processing of NUS spectra (≥ 10 years duration) for ≥ 20 users,
— service contract for 10 years or longer for the complete spectrometer, including magnet, console, and probes.