Pick-up coil

At the location at the pick-up coil system (some 2.5 tube diameters away from the driver) the net field inside the tube is primarily due to the external field. See Fig.3. 

Support plates cause shielding as the pick-up coil passes through and flaws beneath and near the support plate on the far side are not detectable. 

There will be a signal only when the flaw passes the pick up coil system. 

Figure 3 presents the dependence of the modulus of the e.m.f induced in the pick-up coil, on the distance between the transducer and the discontinuity, obtained both theoretically using the Rel. (6) and experimentally. The working fi equency is 5 kHz. The transducer has been balanced for a material zone far from the discontinuity. The modulus of the output e.m.f of the utilized control equipment was devided by the overall gain of the measuring chain, to directly obtain the transducer output voltage. 

By examining the results presented in figure 3, one can notice that the very well marked central peak correspons exactly to the passage of the pick-up coil over the discontinuity, which... 

The polarity of both the drive coil and pick-up coil of the Mossbauer motor can be changed together without changing the performance. 

Experiments using a standard electromagnet can be performed by measuring the strain modulated biased transverse susceptibility (Kraus 1989). In this measurement, a static bias field is applied in the film plane, now perpendicular to the film axis, while the ac driving field is parallel to that axis. The susceptibility (transverse to the bias field) is detected by the pick-up coils and its reciprocal value is then a linear function of both the dc bias field (tfdc) and the magnetoelastic field (Ha = 3As[Pg.109]

The dHvA measurements were carried out using a field modulation technique at liquid helium temperatures and in magnetic fields up to 6 T. Second harmonic frequency signals of the pick-up coil were detected and analyzed by fast-Fourier analysis. 

In order to elucidate the details of the magnetization distribution in the bulk of the sample, several pick-up coils were used. They were inductively coupled with different parts of the crystal (Fig. 6). 

Figure 5. Disposition of pick-up coils on the sample. 1,2,3 - lead-ins of the coils aligned along [001], [110] and [110] directions, respectively (a) and scheme of the sample mounting (b) [1,2],...

Figure 6. Cross section of the sample with three pick-up coils (a, b, c) aligned along [001]. Schematic presentation of magnetic flux coupling to the ddifferently shaped parts of the sample (1, 2, 3), together with the turns of the coil [1,2].

D. B. Laubacher, Portable Nuclear Quadrupole Resonance Detection System for Detecting Presence of Explosives by Scanning Mail and Luggage, Uses High Temperature Superconductor Self Resonant Planar Transmit and Pick-Up Coil, US Patent Application No. US2004245988-A1 (2004). 

Free induction decay after a 90° pulse. (A) A 90° pulse rotates M from (close) to the Z axis to the Y axis, where a pick-up coil detects the signal. (B) Signal detected decays with time this is the induced signal in the /-axis coils. 

In a pick-up coil system the induced voltage Ui d oc dM/dt = dM/dS dS/dt is detected. With a little mathematics the pick-up signal can be calculated and is given by... 

The mechanical vibration of the probe is transferred through a second welded node point along the upper spring rod to the pickup end of the detector. The pick-up end consists of an armature and coil arrangement which is similar to that of the driver end one exception being that the stator of the pick-up coil is a per-... 

Cam and crank sensors are classified by the type of sensing element MRE (fer-romagnetoresistive effect) sensor, Hall (Hall effect) sensor, and MPU (magnetic pick-up coil) sensor. Tab. 7.10.1 provides a summary of the principles and characteristics of the cam and crank sensors according to which element is employed [2],... 

Other advantages are as follows the use of a 40-Hz scanning frequency results in a very small amplitude of motion which reduces geometry distortions to negligible proportions for most nuclides and minimises errors from non-linearities in the voltage/velocity correspondence of the pick-up coil. Half-life corrections with short-lived sources are also unnecessary, and high velocities can be achieved at relatively small amplitudes. One particular system accumulates two spectra simultaneously using a common input to the analyser [28]. 

Note that is unaffected by the transformation. In the nuclear magnetic resonance spectrometer of Fig, 6, the pick-up coil is oriented in such a way that M, is measured. If the lock-in amplifier is set to detect the siginal in-phase with the exciting rf-field ( cos (cot), cf, Eq. (13)), we obtain the "absorption mode signal (cf. Fig. 7) ... 

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