Attachment 1- 600 MHz Spectrometer System Requirements.docx

REQUIREMENTS

The Naval Research Laboratory (NRL) has a requirement for a 600 MHz Nuclear Magnetic Resonance (NMR) Spectrometer for advanced studies of solids and liquids.

The proposed purchase is a solid-state high field Nuclear Magnetic Resonance (SS-NMR) Spectrometer consisting of a 14.0 Tesla (600 MHz) superconducting magnet system, a four channel NMR console, one solution NMR probe and two solid-state NMR probes.

The contractor shall provide a 600 MHz Nuclear Magnetic Resonance (NMR) Spectrometer that at a minimum meets the requirements described below.

1) Spectrometer Console: all electronics except NMR probes The NMR console specifications are divided into transmitter, receiver, hardware accessories, and computer and software.

1a Transmitter The transmitter must consist of a minimum of 3 independent and synchronizable rf channels. The frequency ranges of all of the rf channels cover a minimum range from 15 to 600 MHz (41K to 1H). The amplitude, phase, and frequency of the rf channels must be under computer control for producing phase-shifted pulses, shaped pulses, and variable level cross polarization and decoupling. In addition, the amplitude, phase, and frequency (limited range) must have the capability to be set and changed within a pulse program. The required range, resolution, and settling times are given in Table 1.

Table 1: Capabilities of transmitter

The high power amplifiers must be driven by the console and provide linear operation. Two high frequency amplifiers must be provided: one to cover 1H and 19F at 600 and 564 MHz respectively with a minimum output of 500 W. Two low frequency RF amplifiers must be provided to cover the frequency range of 15-242 MHz (41K to 31P) with a minimum output of 500 W. The high power amplifiers must provide power sufficient to produce the maximum RF fields specified for the probes described below.

1b Receiver There are two aspects to the receiver—the digital system which can be considered part of the console and the hardware system which consists of low power low noise rf preamplifiers.

i) receiver console: The receiver must be capable of digitizing signals in the frequency range of 15-242 MHz (41K to 31P). The receiver must provide for quadrature detection with up to a 10 MHz spectral width and a digital resolution of 17 and 19 bits for SWH < 5 MHz and 1 MHz respectively. The receiver must be capable of digitizing and storing ≥8 M complex data points. The digitization rate must be controllable with an internal clock and by external events. The gain within the receiver console must be controllable over a range greater than 60 dB in ≤6 dB steps. The recovery time from end of blanked pulse to linear operation within the receiver console much be less than 3 ms. Filtering of the input signals must be provided, with the filter cut-offs under console computer control, and cut-offs ranging from 1kHz to ½ the maximum digitizer bandwidth. Digital filters must be compatible with interleaved RF and acquisition events.

ii) preamplifiers: The dual solids-liquids nature of this spectrometer will necessitate a series of rf preamplifiers. Their properties are summarized in Table 2. Additional features should include active transmit/receive switch and built-in RF power detection.

(600 and 564 MHz)

(20 to 564 MHz)

(20 to 564 MHz)

(150 MHz)

(92 MHz)

Table 1: Preamplifier

1c Hardware accessories Here we list some of the key accessories necessary to achieve the required capabilities of the Spectrometer.

i) Gradient controller compatible with the solution NMR probe listed below, i.e., one which allows the NMR probe to reach its specifications.

ii) Low temperature equipment including digital control unit to allow operation down to 77 K.

iii) High temperature equipment including digital control unit to allow operation up to 150 ºC.

iv) Microprocessor based MAS pneumatic unit capable of maintaining spinning accuracy to < 0.1% over entire temperature operation range for all probes purchased.

v) Gas flow system to control sample insert/eject and variable temperatures within probes

vi) Field lock equipment

vii) A variety of RF filters will be provided as necessary to achieve the full acquisition capabilities of the Spectrometer and the NMR probes—see attached document for specific examples.

1d Computer and software The host computer must be a commercially available workstation with at least 2 GB of RAM, a hard disk drive with at least 250 GB capacity, DVDRW drive, 22" color monitor, keyboard, pointing device, and ethernet port supporting the Transmission Control Protocol/Internet Protocol (TCP/IP) for connection to the local network. Disks and manuals for the operating system and spectrometer control software will be provided.

The computer must provide for acquisition and storage of NMR data, and control and storage of all spectrometer parameters including, but not limited to, shims, MAS rotor speed, and probe temperature. The computer must be capable of controlling the variable temperature unit such that an arbitrary list of temperatures can be entered and used in an automated sequence of experiments. The computer must include software for acquisition, processing, simulation, curve fitting, and display of 1-, 2-, and 3-dimensional data and for pulse program and macro editing / compiling.

The contractor shall, for the duration of the warranty period, provide at no additional cost the latest software upgrades of operating system, system software, simulation and curve fitting packages.

While some of the hardware requirements for the pulse programmer have been discussed above in section 1a: Transmitter, here we emphasize requirements more closely associated with the software. The pulse programmer must be capable of being used to perform the experiments listed in the Appendix Table A1. The pulse programmer must have at least 2 k words of memory for pulse programs and at least 64 k words of memory for amplitude, phase, and frequency shaping of rf pulses for each transmitter channel. The memory for pulse shaping must be configurable for simultaneous multiple waveforms. The minimum pulse program interval must be ≤50 ns, maximum pulse program interval ≥1000 s, and pulse program interval timing resolution ≤15 ns. The minimum repetition time of the pulse program must be ≤5 ms. The pulse programmer must control the amplitude, phase, and frequency of rf pulses, the amplitude of magnetic field gradients, transmitter/receiver blanking/gates, and initiation of data acquisition, as well as provide at least 8 user-definable output lines. It must be synchronizable with the MAS rotor or other external event, capable of controlling MAS rotor speed, and provide an external digitizer clock for synchronizing data acquisition with the pulse program. The pulse program structure must allow for: loops and nested loops; branching; arrays, tables, or lists of any parameter values; calculation of dependent variables.

2) Superconducting Magnet The 600 MHz superconducting magnet will have a Standard Bore (SB) with 54 mm bore size—this is critical for compatibility with the NMR probes listed below. Two of the most critical specifications for this magnet are field stability and helium hold time. The field stability must have a guaranteed drift rate of <10 ppb/hr. The helium hold time must approach 1 year under standard conditions. Other details requirements are given in the attached document.

3) NMR Probes

3a Solution NMR probe The triple resonance probe will be optimized for X-nuclei observation with 1H and/or 19F decoupling and for 1H observation (indirect detection). The X-nuclei range will correspond to 19F (564 MHz) and the broad band range 31P (243 MHz)-109Ag (28 MHz) excluding 171Yb (106 MHz)-9Be (84 MHz). The probe must be designed for 1H and/or 19F decoupling and observation with minimum 19F background. Additional specifications are listed in the attached document. Specifications to the performance are summarized in Table 3.

Table 3: Sensitivity specifications for solution NMR probe.

3b Solid NMR probe for very high spinning frequencies This double resonance probe will be optimized for X-nuclei observation with 1H and/or 19F decoupling. The X-nuclei range will correspond to 15N to (61 MHz) to 31P (243 MHz). The most critical specification of this NMR probe is the maximum rotation frequency of 111 kHz or greater. Other specifications are listed in the attached document and Table 4 below.

13C ≤ 1.5 µs; 160 kHz 15N ≤ 2.0 µs; 125 kHz

13C ≤ 2.5 µs; 100 kHz 15N ≤ 3.1 µs; 80 kHz

19F ≤ 0.71 µs; 350 kHz

Table 4: Specifications for 0.7 mm DR MAS NMR probe

Due to the highly specialized nature of this probe other tools and equipment will be required as listed in the attached document.

3c Solid NMR probe with two interchangeable probe heads This highly specialized NMR probe will have a single probe base module and two interchangeable probe heads, one for 1.6 mm rotors and one for 2.5 mm rotors. The probe is designed to fit in the Standard Bore (SB) superconducting magnet described above. A critical unique feature of the probe is light illumination capability. Detailed specifications for the two probe heads are summarized in Tables 5 and 6 below.

13C: 2.0 ms 31P: 2.0 ms 15N: 2.7 ms

Table 5: Specifications of 1.6 mm probe head

13C: 2.4 ms 31P: 2.4 ms 15N: 3.8 ms 39K: 6.1 ms

Table 6: Specifications of 2.5 mm probe head

Appendix Table A1 lists standard NMR experiments and pulse sequences, all of which much be feasible with the Spectrometer and many of which should be demonstrated at the time of installation. The overall spectrometer stability over a 12-hour period, as measured experimentally by the reproducibility of the NMR signal amplitude, obtained with a 30° flip angle pulse, shall be ≤ 0.2%, acquisition to acquisition.

Satellite Transition Magic Angle Spinning (STMAS)

Multiple Quantum Magic Angle Spinning (MQMAS)

Combined Rotation and Multiple Pulse Spectroscopy (CRAMPS)

Rotational Echo Double Resonance (REDOR)

Two Pulse Phase Modulation (TPPM)

Small Phase Incremental Alternation with 64 steps (SPINAL64)

Centerband Only Detection of Exchange (CODEX)

Satellite Transition Population Transfer with Hyperbolic Secant Pulse

HNCACB and CBCANH

Table A1: List of standard NMR experiments for solution and solid state.