Protocol: Tancpht1rho  Sequence: tancpht1rho.c  Apptype: solidseq1d

Description: 

Measurement of the H T1rho with a spinlock before constant, linear or 
tangent-ramped cross polarization (CP) between protons and X, with a 
choice of SPINAL64 or TPPM decoupling. Used for measurement of the H 
T1rho with CP preparation and X detection. 

Setup: 

Load a calibrated data set and select the protocol Tancpht1rho.  For a 
new nucleus calibrate CP with Onepul and Tancpx and then select 
Tancpht1rho.  

Select the desired decoupling method, TPPM or SPINAL. The manual file 
onepul describes calibration of decoupling.

Select aHlock to the desired amplitude of the H spinlock. A good 
starting value is aHlock = aH90.  Note that T1rho of H can depend on the 
amplitude of the spin lock.  Also, if the field strength of spinlock is 
equal to n*srate where n = 1,2 the spins will have a short T1 due to 
rotary resonance. 
   
Array tHlock with a log array and use a T2 method with the analyze 
macro to calculate T1rho. 

Parameter Groups: 

90H:  Module:  no
Sequence:  tancpx.c  
Description:  Provides a 90-degree pulse on dec that can be used as a 
              preparation pulse.  Also used to store the dec calibration.
Parameters:  Channels Page
       aH90  - the amplitude of the pulse.
       pwH90 - the pulse length.

cpHX:  Module:  yes
Sequence:  tancpx.c
Description:  Implements constant, linear or tangent-ramped cross 
              polarization from dec to obs. 
Parameters:  Sequence Page
       shHX - 'c', constant, 'l', linear and 't', tangent shape on the 
              channel designated with chHX. 
       chHX - the variable-amplitude channel, 'fr' from or 'to', to. 
       aHhx - median amplitude of the dec channel.
       aXhx - median amplitude of the obs channel.
       bHX - +/- tangent curvature (>0 to 1.0e5).  
       dHX - amplitude width of the ramp. A negative width sets a ramp 
              that starts high and decreases in amplitude.
       tHX - contact time
       ofHX - overall offset on the variable channel
       frHX = 'dec' -  channel with the initial polarization (must be 
              set - not shown).           
       toHX = 'obs' -  channel with the final polarization (must be set 
              - not shown). 
Implementation:  CP hx = getcp("HX",0.0,0.0,0,1); 
Underscore functions: _cp_(hx, phHhx, phXhx);  

spinlockH:  Module:  no 
Sequence:  tancpht1rho.c. 
Description:  Implements a CW spinlock on dec for T1rho measurements with 
              cross polarization. 
Parameters:  Sequence Page
       tXlock - the spinlock delay. 
       aHlock - the amplitude of CW decoupling on dec. 

Hseq:  Module:  yes 
Sequence:  tancpx.c      
Description: Chooses SPINAL or TPPM decoupling on the dec channel 
             during acquisition.
Parameters: Sequence Page - the Hspinal and Htppm groups overlap. 
       Hseq - chooses the decoupling sequence, TPPM or SPINAL. 
Implementation:  DSEQ dec = getdseq("H");  The router implements 
             getspinal() or gettppm(). 
Underscore functions: _dseqon(dec); runs _tppm(); or _spinal();
             _dseqoff(dec); runs decprgoff();  

Hspinal:  Module:  yes 
Sequence:  tancpx.c  
Description:  Implements SPINAL decoupling on the dec channel during 
              acquisition.  
Parameters:  Sequence Page
       aHspinal - amplitude of the dec channel. 
       pwHspinal - approximate 180-degree flip angle on resonance. 
       phHspinal - +/- small angle phase. SPINAL64 is implemented with 
              phases = +/- 1.0, +/- 1.5 and +/-2.0 times phHspinal. 
       chHspinal = 'dec' must be set (not shown).
Implementation: SPINAL dec = getspinal("H"); or DSEQ dec = 
              getdseq("H");  
Underscore functions: _spinal(dec); and decprgoff(); or _dseqon(dec); 
              and _dseqoff(dec);   

Htppm:  Module:  yes 
Sequence:  tancpx.c      
Description:  Implements TPPM decoupling on the dec channel during 
              acquisition.  
Parameters:  Sequence Page
       aHtppm - amplitude of the dec channel. 
       pwHtppm - approximate 180-degree flip angle on resonance. 
       phHtppm - +/- small angle phase. TPPM is implemented 
              with phases = +/- 1.0 times phHtppm for alternating pulses.  
       chHtppm = 'dec' must be set (not shown).
Implementation: TPPM dec = gettppm("H"); or DSEQ dec = getdseq("H");   
Underscore functions: _tppmon(dec); and decprgoff(); or _dseqon(dec); 
              and _dseqoff(dec);   
