Online proceedings - EDA Publishing Association

More documents

Recommendations

Info

11-13 May 2011, Aix-en-Provence, France Optimisation and realisation of a portable NMR apparatus and Micro Antenna for NMR Patrick Poulichet 1 , Latifa Fakri-Bouchet 2 , Christophe Delabie 1 , Lionel Rousseau 1 , Abdenasser Fakri 1 and Anne Exertier 1 ESIEE, 2 BD Blaise Pascal, 93162 Noisy Le Grand, France 1 Laboratoire CREATIS - LRMN UMR CNRS 5220, INSERM U630, INSA de Lyon 3, rue Victor-Grignard, 69616 Villeurbanne, France 2 p.poulichet@esiee.fr (+33) 1.45.92.67.18 Latifa.Fakri-Bouchet@creatis.univ-lyon1.fr (+33) 4.72.44.82.08 Abstract- This paper is focused on two designs and realizations. The first one concerns a prototype of a portable NMR (nuclear magnetic resonance) apparatus. The second one concerns NMR micro antenna realization. For the first part, our goal is the NMR magnetic field homogeneity and the signal-to-noise ratio (SNR) improvement. Since de the volume of the sample to analyse is around 1 cm 3 , the design is optimized to obtain a good SNR. Particularly, the magnet is chosen to obtain a high magnetic field with limited inhomogeneities. The receiver antenna is designed and optimized to have high feeling factor and then more sensitivity. A mixer and a low-pass filter are used in order to limit the bandwidth and reduce the thermal noise. The FID is digitized and addressed to a FPGA which averages successive acquisitions in order to increase the SNR. The final acquisition is processed for determining the FID spectrum. In the second part, a new concept of micro coil is presented in order to measure the small volumes and small concentrations samples by NMR spectroscopy at 4.7 T (200 MHz proton frequency resonance). This micro sensor would offer the possibility of new investigation techniques based on micro coils’ implantation used for in vivo study of local cerebral metabolites of animals models. Keyword: NMR, single side, portable, magnet, micro coil. I. INTRODUCTION The NMR signal measurement requires a static magnetic field B0 and a pulsed frequency varying B1 magnetic field. The studied sample is submitted to these magnetic fields. Then, the B1 magnetic field is applied at a Larmor frequency (1T correspond to 42.57 MHz), is applied, the signal FID (Free Induction Decay) generated by magnetization motion is acquired using a detection coil. In mobile NMR, B0 is generated with an arrangement of magnets in order to deliver a homogeneous magnetic field. For measurement of the relaxation (T2 or T1) or a spectrum, inhomogeneities must be as low as possible particularly if the objective of the measurement is spectroscopy (ΔB0/B0 ≅ 10 ppm). Reference [4] is a review of the different ways of the array magnets setup in order to obtain the best B0 homogeneity. Reference [1] reports the construction of a mobile tomography device by exploiting the concept of movable permanent magnets in the shim unit of a Halbach array. The cross section of a banana placed inside the magnets is presented. Reference [2] proposes a complete procedure for permanent magnet design, fabrication, characterization and shimming. 1H NMR spectrum of a 3 mm 3 sample of water doped with CuSO4 in the shimmed magnet is presented. The half-height full width (HHFW) is about 12 ppm. Reference [3] presents a single-sided mobile NMR apparatus with a small Halbach magnet. It is lightweight, compact and exhibits good sensitivity. Reference [5] the spectrometer design that uses an FPGA. The system is composed of an FPGA chip and several peripheral boards for USB communication, direct-digital synthesis (DDS), RF transmission, signal acquisition, etc. In the FPGA have been implemented a number of digital modules including three pulse programmers, the digital part of DDS, a digital quadrature demodulator, dual digital lowpass filters, and a PC interface have been implemented. The feasibility to use a new generation of microcoils was proposed in a recent study [6]. It demonstrated potential opportunities in terms of increased signal-to-noise ratio (SNR), spatial resolution, and limits of detection (LOD) [7] compared to the surface-coil [8]. Their use for localized spectroscopic studies of NMR observable cerebral metabolites into 2mm 3 region of interest (ROI), aims to push limits of in vivo detection. II. MOBILE NMR In our design, we used the mains parts describe in [5] in order to realize portable NMR apparatus dedicated to portable NMR. The aim is to optimize the SNR. The magnet (alnico) uses two large piece of steel in order to reduce inhomogeneities of the magnetic field. Fig. 1 shows the functional schematic of the spectrometer connected to the PA (Power Amplifier) and connected to 193
the LNA (Low Noise Amplifier). The duplexer use a circuit with two diodes for ensuring a good isolation when a signal is applied to the generation coil. 11-13 May 2011, Aix-en-Provence, France using USB protocol. There are some daughter cards connected to the FPGA as shown in Fig. 2. The FPGA also ensures that the delivery signal parameters are correct. Fig. 1. Functional schematic of the connexions between the spectrometer and the coils A. Optimisation of the SNR Like the volume of the sample to analyze is around 4,6 cm 3 , we choose the dimension of the air gap, the wire diameter, the noise factor of the preamplifier in order to deliver a signal above the noise. The measured induction B 0 is 0,116 T. With the constant gyromagnetique γ, we determine the Larmor frequency : f 1 0 = γ . 0 4.92 2π B = MHz With the value of the Plank constant h and the Bolzman constant k, we obtain the magnetic moment M0 : B M0 = N. γ .3. = 9,9.10 4. kT . 2 2 0 −6 The FID value is : ξ = K. ω0. BM 1. 0. V when K is an homogeneity factor, B 1 the alternative magnetic field and V the volume of the sample. In order to increase the B 1 magnetic value, a separate inductance from the detection coil was chosen. With a current of nearly 5 A in the generation inductance, ξ = 14 µV. By taking into account the bandwidth of the detection coil Δf = 500 kHz, the spectral density of noise across this inductance is calculated: e n = 1,6.10 -10 V. With the noise factor of the preamplifier, the SNR is calculated: SNR ≅ 100. In this calculus, the noise is underestimated because only the thermal noise from the detection coil and the noise from the LNA are take into account. B. Spectrometer Fig. 2 shows the functional schematic and the realization of the spectrometer used to control FID generation, acquisition and processing. A Cyclone III FPGA is used to control the FID record, acquisition time, sequence repetition time used for NMR, FID storage and transfer to the PC Fig. 2. Functional schematic and realization of the spectrometer To digitize the FID, an ADC 14 bits - 65 MIPS is used. Then data are fed into the FPGA memory. After M samples of N points, the digital word is sent to the PC via USB port. When the acquisition parameters are defined, the generated signal is sent by the DDS and an amplitude modulation is applied if necessary via the DAC. The amplitude and frequency modulation can be used to generate complex shapes of chirps in order to compensate the inhomogeneities of B0. Fig. 3. Magnet and antenna connected to the duplexer The magnet and the duplexer of the Fig. 3 were connected to the LNA and the PA. Using two large pieces of steel, low inhomogeneities are expected. The sample of liquid of the Fig. 3 is placed inside the air gap of the magnet. Fig. 4 shows an acquired signal with a superposed noise and the same signal with noise removed. This last signal is ©<strong>EDA</strong> <strong>Publishing</strong>/DTIP 2011 194
Page 2 and 3:
COLLECTION OF PAPERS PRESENTED AT T
Page 4 and 5:
III
Page 6 and 7:
V
Page 8 and 9:
Table of Contents Wednesday 11 May
Page 10 and 11:
PANEL DISCUSSION TEXTILE MICROSYSTE
Page 12 and 13:
Friday 13 May SESSION C4: APPLICATI
Page 14 and 15:
SPECIAL SESSION OF BIO-MEMS/NEMS a
Page 16 and 17:
11-13 May 2011, Aix-en-Provence, Fr
Page 18 and 19:
11-13 May 2011, Aix-en-Provence, F
Page 20 and 21:
Page 22 and 23:
Page 24 and 25:
suspended membrane can be pulled to
Page 26 and 27:
most likely due to not yet consider
Page 28 and 29:
Page 30 and 31:
that detectors may measure the diff
Page 32 and 33:
2) Cavity width effect To verify th
Page 34 and 35:
Page 36 and 37:
Fig.9. Capacitive sensor output, Va
Page 38 and 39:
11-13 May, 2011, Aix-en-Provence,
Page 40 and 41:
The anode and cathode are connected
Page 42 and 43:
11-13 May , 2011 , Aix-en-Provence,
Page 44 and 45:
Page 46 and 47:
Page 48 and 49:
Page 50 and 51:
! 11-13 May 2011, Aix-en-Provence,
Page 52 and 53:
! 11-13 May 2011, Aix-en-Provence,
Page 54 and 55:
! TABLE 3 SUMMARY OF SELECTIVITIES
Page 56 and 57:
Page 58 and 59:
Page 60 and 61:
Page 62 and 63:
The fabrication of optical Cap-Wafe
Page 64 and 65:
the glass is polished down in a cos
Page 66 and 67:
Page 68 and 69:
Page 70 and 71:
Page 72 and 73:
Fig. 14. Time history of the envelo
Page 74 and 75:
Page 76 and 77:
Page 78 and 79:
We have reported that how base mode
Page 80 and 81:
We assume that 11-13 May 2011, Aix
Page 82 and 83:
Page 84 and 85:
Y X Fig. 1. Scanning electron mic
Page 86 and 87:
10 3 11-13 May 2011, Aix-en-Proven
Page 88 and 89:
Intenstiy (counts/second) Fig. 1. X
Page 90 and 91:
Page 92 and 93:
Page 94 and 95:
etween x 2 to L (remember that x 2
Page 96 and 97:
Page 98 and 99:
Page 100 and 101:
Page 102 and 103:
Page 104 and 105:
Page 106 and 107:
piezoelectric displacement transduc
Page 108 and 109:
Figure 7 Displacement conditions of
Page 110 and 111:
protect the corners from undercut.
Page 112 and 113:
Page 114 and 115:
A. Continuous domain Starting from
Page 116 and 117:
Fig. 8. Central finite difference m
Page 118 and 119:
Page 120 and 121:
700 11-13 May 2011, Aix-en-Provenc
Page 122 and 123:
o o o o o o o o Check applicability
Page 124 and 125:
C. Identification Results The ident
Page 126 and 127:
The proposed solution for this prob
Page 128 and 129:
teen wire segments of a coil, as in
Page 130 and 131:
As the metallization is too reflect
Page 132 and 133:
B. Implemented die overview A die c
Page 134 and 135:
Page 136 and 137:
IN CLK OUT Fig. 16. Probe setup for
Page 138 and 139:
Page 140 and 141:
adhesive material with 30μm thickn
Page 142 and 143:
Page 144 and 145:
Page 146 and 147:
B. Dynamics of Energy Flows For a l
Page 148 and 149:
Page 150 and 151:
Page 152 and 153:
11-13 May, Aix-en-Provence, France
Page 154 and 155:
80˚C. Additionally, we looked into
Page 156 and 157:
The XRD shows a peak above the 2θ
Page 158 and 159: fibers which define the electric co
Page 160 and 161: 11-13 May 2011, Aix-en-Provence, Fr
Page 162 and 163: Figure 15. Key board input system.
Page 164 and 165: ρ = h 2∆α∆T + + E 1h 3 1 +E 2
Page 168 and 169: In recent years, the pipe flow moni
Page 170 and 171: As the speed of the rotor increases
Page 172 and 173: 11-13 May 2011, Aix-en-Provence, F
Page 176 and 177: inches silicon wafers which have th
Page 178 and 179: samples tested in different vacuum
Page 180 and 181: l c 11-13 May 2011, Aix-en-Provence
Page 182 and 183: Vp (V) 3,5 3,0 2,5 2,0 1,5 1,0 0,5
Page 186 and 187: II. MATHEMATICAL MODEL AND NUMERICA
Page 188 and 189: fluids travel along a curved channe
Page 190 and 191: measured mixing indices are depicte
Page 192 and 193: length, which enables them to focus
Page 196 and 197: however, a rotation for coincidence
Page 204 and 205: excludes the nature of the fixed bo
Page 206 and 207: Using the radial and tangential mid
Page 216 and 217: Now the challenge in data handling
Page 218 and 219: value of every active channel. Ther
Page 222 and 223: 11-13 May, Aix-en-Provence, France
Page 224 and 225: 11-13 May, Aix-en-Provence, France
Page 230 and 231: electrocardiogram. • The heart be
Page 234 and 235: In our work, we proposed an innovat
Page 236 and 237: Fig. 8 Concept of the in-home perso
Page 238 and 239: found that the early-stage diagnosi
Page 244 and 245: Power monitoring data detected by w
Page 248 and 249: device consisted of a bimorph canti
Page 250 and 251: where C others is the capacitance o
Page 258 and 259:
operation, the pressure inside the
Page 260 and 261:
Page 262 and 263:
increased. 11-13 May 2011, Aix-en-
Page 264 and 265:
Page 266 and 267:
coefficient compatible with the mic
Page 268 and 269:
Page 270 and 271:
Variable Description Value Crab-leg
Page 272 and 273:
Page 274 and 275:
Page 276 and 277:
Membrane weight (mg) Fig. 4. Struct
Page 278 and 279:
Page 280 and 281:
Page 282 and 283:
So far, the expected major contribu
Page 284 and 285:
al. used a modified LIGA (German ac
Page 286 and 287:
Page 288 and 289:
Page 290 and 291:
Page 292 and 293:
REFERENCES [1] G. Mehta, J. Lee, W.
Page 294 and 295:
Page 296 and 297:
followed by titanium (Ti) which sho
Page 298 and 299:
exposure dose, post exposure bake t
Page 300 and 301:
#### ##/&### 3 # #
Page 302 and 303:
*5%6,+/.,-,7-, ,+.,1/21* %
Page 304 and 305:
B. Energy Applications Society is f
Page 306 and 307:
Page 308 and 309:
Page 310 and 311:
Page 312 and 313:
Page 314 and 315:
Presently, the microfabrication pro
Page 316 and 317:
[6] C. Richard, A. Renaudin, V. Aim
Page 318 and 319:
NA sinθ c 11-13 May 2011, Aix-en-
Page 320 and 321:
the waveguide on the fused silica,
Page 322 and 323:
microphone diaphragm. The chosen CM
Page 324 and 325:
Page 326 and 327:
TABLE V MICROPHONE CHARACTERISTICS
Page 328 and 329:
Page 330 and 331:
Figure 7b shows the effect of a par
Page 332 and 333:
Page 334 and 335:
over the temperature range (i.e. th
Page 336 and 337:
Page 338 and 339:
Page 340 and 341:
given. This allows a CTM model to b
Page 342 and 343:
Page 344 and 345:
Page 346 and 347:
Page 348 and 349:
the magic-Tee, and the coherent sig
Page 350 and 351:
Page 352 and 353:
After analyzing the two conditions
Page 354 and 355:
IV. MICRO FABRICATION For fabricati
Page 356 and 357:
Page 358 and 359:
IV. A. Simulation and Sensitivity A
Page 360 and 361:
Page 362 and 363:
Page 364 and 365:
Page 366 and 367:
grown to sub-confluence were washed
Page 368 and 369:
Page 370 and 371:
Clamps rotation [21] Clamps transla
Page 372 and 373:
Layout Total dimensions of the grip
Page 374 and 375:
Page 376 and 377:
focusing increased both as the stre
Page 378 and 379:
Page 380 and 381:
Time of diffusion (hr) 1200 1000 80
Page 382 and 383:
Page 384 and 385:
Page 386 and 387:
Chip Magnet Light source Hot plate
Page 388 and 389:
above, they would move to upward an
Page 390 and 391:
Page 392 and 393:
Page 394 and 395:
Page 396 and 397:
Page 398 and 399:
Page 400 and 401:
This phenomenon is now reaching the
Page 402 and 403:
C. Proof mass displacement Moreover
Page 404 and 405:
Page 406 and 407:
Page 408 and 409:
The VerilogA block code is : 11-13
Page 410 and 411:
Author Index Abi-Saab D. 81 Aimez V
Page 412:
Nussbaum Dominic 273 O’Hara T. 35
show all

Online proceedings - EDA Publishing Association

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?