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Disk chopper time-of-flight spectrometer IN5
IN5 is a high precision direct geometry Time-of-flight (ToF) spectrometer. It is used to study low-energy transfer processes as a function of momentum transfer (e.g. quasi-elastic scattering in solids, liquids, molecular crystals and inelastic scattering, etc ). Typically this instrument is used for measurements in the small energy (10 µeV - 100 meV) and momentum transfer region with values of about 1 % for the energy resolution .
Example of standard analysis
Procedures for IN5 data treatment for LAMP in runtime modeThe following compressed file contains the compiled procedures that have to be used for the IN5 data treatment, e.g., with standard1.prox below. This file standard.tar.gz (last changes: 2010/11/19) has to be uncompressed in the .../Free_Lamp/lamp/lamp_mac/ directory. The compiled routines (.sav) should then be accessible from LAMP after a restart of LAMP. A brief help on the used routines is given below the prox example. If using LAMP with an IDL licence one can alternatively compile the routines found in standard_sources.tar.gz.
Bugs reports and questions to: J. ollivier (ollivier(at)ill.fr) Standard1.prox; --------------------------------------------------------------------- ; Help on IN5 routineshelp on in5_ IDL routinesLast modified: Thu Oct 15 15:52:34 2009.
List of Routines
Routine DescriptionsIN5_CORRTOF[Next Routine] [List of Routines]
For IN4, IN5, IN6 and D7 data. /deteff : corrects for energy-variation of detector efficiency /frameoverlap : subtracts a t^-4 tail from the beginning of the time frame & shift the elastic peak /background : subtracts a flat background in each detector, found using a moving filter (For IN4, IN5 and IN6 only) NO MORE VALID on the transformed data. Must be applied before on the raw time-of-flight data. The moving window width can be changed with the keyword: window = [value] : default is 20. Must be used in conjunction with /background /psd : If inst = IN5 need this keyword for the detctor efficiency of the PSDs. /verbose : More info during execution. w2 = corrtof( w1,/deteff, window=15,/background, /verbose ) Since 10/2008 : w2 = corrtof( w1,/deteff, /psd, window=15,/background, /verbose ) Keyword PSD means using the new PSD detectors. (optional keywords shown in square brackets) written by: KHA,JRS 23/6/03 revisions: JO, 20/12/04 detector efficiency correction as implemented in INX for IN4, IN5, IN6 and MIBEMOL. JO, Mon Nov 24 14:17:47 CET 2008: Add detector efficiency as for 1 inch tubes IN5/IN6 (wait for Van Esch calculation ?) JO, Fri Jan 23 10:35:44 CET 2009: Correct the w_in background substraction: W_in was affected by the substraction, not normal... (See in5_corrtof.pro)
IN5_ENERGY_REBIN[Previous Routine] [Next Routine] [List of Routines]
rebins output workspace from t2e to constant energy bin width. otherwise: rebin only where dE is > point spacing (default) /keepelastic : do not rebin over the elastic peak Emin = energy minimal to start the exit workspace. (optional keywords shown in square brackets) KHA,JRS 16/03/05 Modifications: JO, ??? add verbosity JO, Tue Nov 25 11:12:49 CET 2008: Improve output parameters presentation (See in5_energy_rebin.pro)
IN5_ESTRIP[Previous Routine] [Next Routine] [List of Routines]For IN4, IN5, IN6 and D7 Rebins output data from t2e and reb to regular-grid S(Q,w) data using the old KHA IN6 rebin algorithm. Selects a single E-value. Input workspace must be in energy transfer versus scattering angle, i.e. only one component or spin phase.
dE : Width of E-strip dQ : Q bin width /neg_angles : use only negative angles /pos_angles : use only positive angles /all_angles : use all angles (default) input workspace must be in energy transfer versus scattering angle, i.e. only one component or spin phase. (ev, eb, qb and ib are obsolete, kept for backwards compatability) (Optional keywords shown in square brackets) Modifications : JOR 2009/08 Reverse array direction for negative angles for D7 only! Add prefix in5_ (= trusted IN5) and on demand verbosity. (See in5_estrip.pro)
IN5_GROUP[Previous Routine] [Next Routine] [List of Routines]
Intensity is the averaged value. output information w2 = group(w1,filename='angles.ang', /verbose) ; group spectra according to the file 'angles.ang'
filename : name of a file where the spectra numbers are given for each group. Angles must be in column and in LAMP format, i.e., starting from 1 and going to 88, 90 before 2006 and up to 395 for the renewed IN5. e.g.: 1 7 8 15 ... Means: group 1 include spectra 1 to 7, group 2, spectra 8 to 15, etc. Last value lower than the number of remaining groups after remove_spectra Bad groups must have been removed with remove_spectra first /verbose : more info during execution Revisions: + S. Rols 10.08.02 rols@gdpc.univ-montp2.fr + M.Plazanet 2005: add the possibility to group according to an angle group file 'angles.ang' + JO 2006-11-22: Improved version for the group file, verbosity added. (See in5_group.pro)
IN5_NORMALISE[Previous Routine] [Next Routine] [List of Routines]
detector=detector, alldetectors=alldetectors, ei=ei, $ madangles=madangles, zeroshift=zeroshift, nopo = nopo, $ inorm, ikeep For IN4, IN5, IN6, HET and D7 data. For IN4, IN5 and IN6: --------------------- Normalises raw data to monitor or counting time, depending on value of inorm. Finds the position of the elastic peak. KEYWORDS: /raw : no normlisation (error bars calculated) /monitor : normalise data to 1000 monitor1 counts (DEFAULT) /time : normalise data to counting time (will not work for summed data) (inorm and ikeep are obsolete, kept for backwards compatability) For HET: -------- Normalises raw data to monitor 1 (must be monitor 1 for ISIS data). Removes empty spectra. User must input incident energy. ARGUMENTS: ei : incident energy of measurement For D7: -------- Normalises raw data to monitor (default) or counting time or individual detector. Extracts every other spectrum if desired (=> nbSpectra=32). Recalculates detector angles based on a YIG calibration by default. ARGUMENTS: detector : detector number to normalise to zeroshift : angle in degrees of 2theta = 0 (inorm and ikeep are obsolete, kept for backwards compatability) KEYWORDS: /raw : no normlisation (error bars calculated) /monitor : normalise data to 1000 monitor1 counts (DEFAULT) /time : normalise data to counting time /alldetectors : supresses the removal of the odd numbered detectors /madangles : supresses the recalculation of the detector angles using the current YIG calibration DIMENSIONS: non-TOF data: w_out(nbSpectra,nphases,nruns) -unless nphases is 1 TOF data: w_out(nbChannels,nbSpectra*nphases,nruns) DCOMMAND SYNTAX: w2=normalise(w1[,/raw][,/monitor][,/time][,detector=#][,/alldetectors][,/rawangles][,ei=#]) (optional keywords/arguments shown in square brackets) Writtne by: KHA,JRS 29/7/04 Modifications: S. Rols 09/01 srols@anl.gov: Normalization for mibemol data and DCS JO, ??? Add verbosity and use str_fit instead of fitgauss (due to) problems with the errors computation. JO, Tue Dec 9 18:12:50 CET 2008: correct normalise for the 3D raw data with the new PSDs. Add ELP calculation in that case. (See in5_normalise.pro)
IN5_QSTRIP[Previous Routine] [Next Routine] [List of Routines]For IN4, IN5, IN6 and D7 rebins output data from t2e and reb to regular-grid S(Q,w) data using the old KHA IN6 rebin algorithm. Selects a single Q-value. Input workspace must be in energy transfer versus scattering angle, i.e. only one component or spin phase. Qvalue: Q-value at centre of extracted strip dQ : Width of Q-strip /neg_angles : use only negative angles /pos_angles : use only positive angles /all_angles : use all angles (default) input workspace must be in energy transfer versus scattering angle, i.e. only one component or spin phase. (ev, eb, qb and ib are obsolete, kept for backwards compatability)
(optional keywords shown in square brackets) Modifications : JOR 2009/08 Reverse array direction for negative angles for D7 only! Add prefix in5_ (= trusted IN5) and on demand verbosity. (See in5_qstrip.pro)
IN5_REMOVE_SPECTRA[Previous Routine] [Next Routine] [List of Routines]
Removes spectra with numbers given in array badspecs. Spectrum numbers run from 1 to nspectra. This is necessary in cases where other_tit exceeds 160 characters /verbose : add verbosity to the standard output.
BadSpectra: String of bad spectra to remove. Syntax is : '1-40,87,90,93,356-367' '1-40' means all spectra from number 1 to number 40, etc. or (new version): w2 = remove_spectra(w1,BadSpectra = '1-87,112-121,234,235,236,256-273',/verbose) JO, Mon Jun 16 14:24:35 CEST 2008 Modif to take a group of detectors instead of individual numbers. e.g. w2 = remove_spectra(w1,BadSpectra = '1-87,112-121,234,235,236,256-273') in that case, the BadSpectra string replace the badspecs input. (See in5_remove_spectra.pro)
IN5_SAFCORR[Previous Routine] [Next Routine] [List of Routines]
similarly to INX routines. For slab samples, the calculation is identical to INX as taken from the Sears calculations (V.F. Sears Adv. Phys. (1975)). For cylinders (full/hollow) the calculation is similar to those of J.Wuttke (ILL report WU....) and differs slightly formt the calculation from Rieutord (ILL report RI.... 1991) as implemented in INX but the results are similar. In all cases, contrarily to the INx and SQW routines, the SAF corrections are computed for each energy.
sigma_s: Total scattering cross-section (barns) rho: sample density (g/cm^3) Mass: molar mass (g/mol) Rin: Inner radius (full/hollow cylinders). Unit: [mm] Rout: outer radius (full/hollow cylinders). Unit: [mm] thick: Slab thickness (flat plate -- slab -- samples). Unit: [mm] angle: Slab setting angle (flat plate -- slab -- samples). Unit: [deg.] /corrections: Gives the Self Attenuation Factors instead of the corrected intensities Size = size(w_in) hlp = hlp Gives this help If keyword '/corrections': gives the correction map Corr such as: W_out = W_in/Corr instead of W_out. w8=safcorr(w7,thick=0.5,angle=135.0,sigma_a=5.08,sigma_s=5.205,rho=5.96,Mass=50.941) Performs self-absorption / self-attenuation for w7 (here parameters are for vanadium slab at an angle of 135 deg) (optional arguments shown in square brackets) For a cylinder (full or hollow) sample: w8=safcorr(w7,Rin=10.0,Rout=11.0,sigma_a=5.08,sigma_s=5.205,rho=5.96,Mass=50.941) For a full cylinder set Rin=0 or cancel the keyword in the routine: w8=safcorr(w7,Rout=11.0,sigma_a=5.08,sigma_s=5.205,rho=5.96,Mass=50.941) w3 = safcorr(w2,Rin=0,Rout=12,sigma_a=5.08,sigma_s=5.205,rho=5.96,Mass=50.941,/verbose,/corrections) for a vanadium full cylinder, gives the corrections factors instead of the corrected intensities Modified by: JO-2006-06-15: Corrected a bug 2 times win/H1 in safcyl JO-2006-11-10: Compute energies. Data need no more to be in energy mode. Warning: all cases are not treated , MIBEMOL should not work. JO-2008-11-25: Treat correctly the case where all is in time channel. Improve verbosity. (See in5_safcorr.pro)
IN5_T2E[Previous Routine] [Next Routine] [List of Routines]
convert tof spectrum in w1 to energy and output in w2 Energies are in x2. w2 = t2e(w1,/verbose) ; same with information on the standard output. w2 = t2e(w1,w3,/verbose) ; Uses an elastic peak standard raw data reference for finding the elastic peak position (ELP). The Vanadium or better the low temperature sample is this reference usually. This is required each time the ELP is incorrectly defined in the sample. E.g. on liquid spectra. /average_elp : take average elp instead of W_van : Workspace for the vanadium/low temp. sample, that gives the elastic peak reference /verbose : more info during execution Written by GJK 1994 Revisions: JO 2004-11-03 Include other Tof instruments (e.g.: MIBEMOL, LLB) JO 2006-03-28 Html help, more verbosity JO 2006-10-23 tee -> t2e with the same properties in case the original t2e fails. JO 2006-11-10 gaussian fit with str_fit instead of fitgauss (due to problems when error bars are not computed), with the same restriction to the elastic peak than before +/- 30 channels from mean elastic maximum. JO 2006-12-14 Reference of the elastic line by the vanadium (keyword: Wvan) Vanadium data must be in the same format than sample data. JO, 2007-11-05 Seems that the gauss ELP is 1 channel out from the reality. Is it always true ??? JO, Sat Oct 11 11:57:30 CEST 2008: If spectra are zeros remove first and last index str_fit gives the first X if no maxi found JO, Thu Dec 4 10:55:17 CET 2008: correction on the index ind (See in5_t2e.pro)
IN5_T2EPSD[Previous Routine] [Next Routine] [List of Routines]
Same as in5_t2e but adapted for PSDs. ; JO 2008-07-01 This version T2EPSD adapted for IN5 PSD but other instruments removed for clarity. (See in5_t2epsd.pro)
IN5_VNORM[Previous Routine] [List of Routines]
chmin : lower time channel limit of integration over vanadium elastic peak chmax : upper time channel limit /verbose : more info during execution - normalises data in w1 to vanadium data in w2 and store the result in w3 (optional arguments shown in square brackets). w3 = vnorm(w1,w2, chmin=490,chmax=520) ; only a few case require to put the limits by hand. Modified by: S. Rols (for mibemol data) 4/12/03 J. ollivier (2006-03-21) New version with vanadium temperature correction for the Debye-waller factor. Add verbosity on the standard output. Calculation of the integral limitsautomatic. WARNING: D7 case removed for clarity of the code!!! (See in5_vnorm.pro)
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