 Physics Help Forum Fourier Transform NMR Physics... Work Shown... Please Help!!!!!!!

 Electricity and Magnetism Electricity and Magnetism Physics Help Forum Oct 13th 2009, 05:50 PM #1 Junior Member   Join Date: Oct 2009 Posts: 3 Fourier Transform NMR Physics... Work Shown... Please Help!!!!!!! Suppose you would like to detect the NMR signal from water within an area of the brain using a 2 Tesla Magnet. Intially, the magnetization from the protons in water has a magnitude (length) represented by Mo and oriented in a direction parallel to the z-axis (defined as the direction of the external magnetic field (Bo)). In order to observe the NMR signal this magnetization is rotated into the x,y plan (using the B1 magnetic field). a.) At what frequency in (MHz) does the magnetization (now in the x,y plane) precess about the external magnetic field (Bo). b.) If the magnitude of B1 is 1.5 mT, how long does it take for the magnetization to rotate into the x,y plane from it's intial position parallel to the z-axis? My work: f0= (y/2pi) (Bo) since (y/2pi) is equal to 42.6 MHz/T for H1 therefore, f0= (42.6 MHz/T) (2T)= 85.2 MHz exp (-t_(1/2)/ T2*)= 1/2 -t_(1/2) / T2*= -ln 2 t_(1/2)= T2*(ln(2)) # of cycles= t_(1/2)/ T_period = t_(1/2)*(f0)= T2*(ln(2))*f0= 50x10^3 us (ln 2) (85.2 MHz) = 3 x10^6 cycles b.) B1= 1.5mT # of cycles = 3 x 10^6 f0= 85.2 x 10^6 =8.52 x 10^7 Hz= 8.52 x 10^7 cycles/sec # of cycles/f0= 3x 10^6 cycles/ (8.52 x 10^7 cycles/sec) = 3.52 x 10^-2 sec Please help me with these questions, I showed my work.. need help  Tags fourier, nmr, physics, shown, transform, work Thread Tools Show Printable Version Email this Page Display Modes Linear Mode Switch to Hybrid Mode Switch to Threaded Mode Similar Physics Forum Discussions Thread Thread Starter Forum Replies Last Post tracker890 Electricity and Magnetism 2 Apr 29th 2014 06:33 PM tracker890 Electricity and Magnetism 2 Apr 22nd 2014 02:02 AM Diomarte Advanced Waves and Sound 1 Dec 2nd 2010 03:10 PM johnq2k7 Advanced Electricity and Magnetism 0 Oct 13th 2009 05:51 PM nairbdm General Physics 3 May 7th 2008 06:43 AM 