Feasibility study neutron diffraction at IRI

IRI-132-95-05

NL96FJ011

Feasibility study neutron diffraction at IRI V.-O. de Haan

Interfacultair Reactor Instituut Technische Universiteit Delft / Delft University of Technology June 1995

\r
O C (I.E. IF ANALYTICAL OPTIMIZATION IS REQUIRED) C IMPORTANT: THE INCLINATION ANGLE GIVEN HERE IS MEASURED FROM THE C INCIDENT BEAM DIRECTION IN THE TRIGONOMETRIC SENSE! FURTHER IN THE C PROGRAM IT IS MEASURED FROM THE SYMMETRICAL TRANSMISSION POSITION IF(NSAM.Eq.0)READ(l,2)DIASAM,HSAM,ABSAM IF(NSAM.NE.0)READ(l,2)WSAM,THSAM,HSAM,ALFASAM,ABSAM C READ THE INDICES KV(5) FOR NSAM=O OR KV(5),KV(6) FOR NSAM=1, C SPECIFYNG WHETHER THE SAMPLE THICKNESS (OR DIAMETER, IF NSAM=O) C AND THE SAMPLE INCLINATION ANGLE SHOULD BE INCLUDED IN THE C OPTIONAL NUMERICAL OPTIMIZATION (1 FOR YES.O FOR NO) IF(NSAM.NE.0)READ(l,l)KV(5),KV(6) IF(NSAM.EQ.0)READ(l,l)KV(5) C READ THE DETECTOR WINDOW DIAMETER IF NDET=O OR ITS C WIDTH AND HEIGHT IF NDET=1 IF(NDET.EQ.0)READ(l,2)DIADET IF(NDET.NE.0)READ(l,2)WDET,HDET C READ THE INDEX KV(16) SPECIFYING WHETHER THE DETECTOR WINDOW C SHOULD BE OPTIMIZED NUMERICALLY (1 FOR YES, 0 FOR NO) READ(1,1)KV(16) IF(IC.EQ.1)GO TO 68 C READ THE DISTANCES SOURCE-MONOCHROMATOR(EXIT OF NEUTRON GUIDEC MONOCHROMATOR IF THERE IS A NEUTRON GUIDE),BETWEEN THE 2 C CRYSTALS OF THE MONOCHROMATOR UNIT(ONLY IF IC=2).MONOCHROMATORC SAMPLE AND SAMPLE-DETECTOR,ALL IN CM READ(l,2)VL0,VL01,VLl,VL2 C READ THE INDICES KV(7) AND KV(8) SPECIFYNG WHETHER THE DISTANCE C MONOCHROMATOR-SAMPLE OR SAMPLE-DETECTOR SHOULD BE INCLUDED IN C OPTIONAL NUMERICAL OPTIMIZATION(1 FOR YES.O FOR NO) READ(1,1)KV(7),KV(8) GO TO 688 68 READ(1,2)VLO,VL1,VL2

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C C C C C C C C

C

C

C C C C C C C C C C C C C C C C C C C C C

APPENDIX B. SHORT DESCRIPTION OF PROGRAM DAX

READ(1,1)KV(7),KV(8) 688 IF(NFM.LT.O)GO TO 5 READ THE PARAMETERS OF THE COARSE COLLIMATOR BEFORE MONOCHROMATOR: DISTANCE FROM SOURCE, LENGTH, WIDTH AT ENTRANCE, WIDTH AT EXIT, HEIGHT AT ENTRANCE, HEIGHT AT EXIT (FOR CIRCULAR SHAPE WIDTHS AND HEIGHTS SHOULD BE REPLACED BT THE CORRESPONDING DIAMETERS), ALL IN CM. NOTICE THAT A SOLLER COLLIMATOR SHOULD BE COUNTED TWICE: FIRST AS AN ANGULAR DIVERGENCE IN THE PLANE (EQUATORIAL OR AXIAL) OF COLLIMATION AND SECOND AS A COARSE COLLIMATOR TO ACCOUNT FOR ITS OVERALL DIMENSIONS READ(1,2)VLCANM,VLSM,HDM1,HDM2,VDM1,VDM2 HDMl=HDMl/2. HDM2=HDM2/2. VDMl=VDMl/2. VDM2=VDM2/2. 5 IF(NFS.LT.O)GO TO 7 READ THE SAME PARAMETERS FOR THE COARSE COLLIMATOR BEFORE SAMPLE READ(1,2)VLCANS,VLMS,HDS1,HDS2,VDS1,VDS2 HDSi=HDSl/2. HDS2=HDS2/2. VDSl=VDSl/2. VDS2=VDS2/2. READ THE SAME PARAMETERS FOR THE COARSE COLLIMATOR BEFORE DETECTOR 7 IF(NFD.LT.O)GO TO 8 READ(1,2)VLCAND,VLSD,HDD1,HDD2,VDD1,VDD2 HDDl=HDDl/2. HDD2=HDD2/2. VDDl=VDDl/2. VDD2=VDD2/2. READ THE SOLLER COLLIMATORS EQUATORIAL ANGULAR DIVERGENCES (FWHM IN MINUTES OF ARC). IF THERE IS NO EQUATORIAL SOLLER COLLIMATION PUT THE CORRESPONDING DIVERGENCE EQUAL TO 0. 8 READ(1,2)(ALPHAM(I),I=1,3) READ THE INDICES SPECIFTNG WHETHER THE SOLLER COLLIMATOR DIVERGENCES ALPHA(I) SHOULD BE INCLUDED IN THE OPTIONAL NUMERICAL OPTIMIZATION(1 FOR YES.O FOR NO FOR EACH OF THEM) READ(1,1)(KV(I),I=9,11) READ THE ANGULAR DIVERGENCES (FWHM IN MINUTES) OF THE AXIAL SOLLER COLLIMATORS. NO AXIAL SOLLER COLLIMATOR IS INDICATED BT PUTTING THE CORRESPONDING DIVERGENCE EQUAL TO 0. READ(1,2)(BETAM(I),1=1,3) READ THE NUMBER OF DATA SETS (CONTAINING THE MONOCHROMATOR BRAGG ANGLE AND THE SCATTERING ANGLE), THE NUMBER OF CYCLES (SCATTERING ANGLE FROM -10.*NCYCLE/2 TO 10*NCYCLE/2 DEGREES WITH A STEP OF 10. DEGREES), AN INDEX NOPT SPECIFYNG WHETHER THE PROGRAM SHOULD OPTIMIZE ANALYTICALLY THE MONOCHROMATOR RADIUS OF CURVATURE AND THE SAMPLE INCLINATION ANGLE IF IC=1 (NOPT=O FOR NO; NOPT=1 IF ONLY THE SAMPLE INCLINATION OPTIMIZATION IS DESIRED, N0PT=2 IF THE ANALITICAL OPTIMIZATION FOR BOTH SAMPLE INCLINATION AND MONOCHROMATOR RADIUS OF CURVATURE IS DESIRED) OR, IF IC=2, WHETHER THE PROGRAM SHOULD OPTIMIZE THE MONOCHROMATORS RADII OF CURVATURES, (NOPT=O FOR NO, NOPT=1 FOR YES) AND POSSIBLY

27 C C C C C

ALSO (IF N0PT=2) THE SAMPLE INCLINATION ANGLE AND THE HONOCHROMATORSAMPLE DISTANCE AND THE PRINTOUT INDEX NWR: FULL (2), MEDIUM (1) OR MINIMAL (0) NEW INDEX NC ADDED, SPECIFYING THE VARIABLE TO BE CYCLED, SEE THE TOP OF THE LISTING READ(1,1) ND,NCYCLE,NOPT,NWR,NC if(nc.eq.0)WRITE(2,4320) 4320 FORMAT(' DANGLE IFULL ISAMPLE IDETECT LINWDT' 1' CRVTURE PKREFL FMERIT') if(nc.eq.l)write(2,4321) 4321 FORMAT(' DANGLE IFULL ISAMPLE IDETECT LINWDT' 1' CRVTURE PKREFL FMERIT') if(nc.eq.21)write(2,43210) 43210 FORMATC DANGLE IFULL ISAMPLE IDETECT LINWDT' 1' CRVTURE2 PKREFL2 FMERIT') if(nc.eq.2)write(2,4322) 4322 FORMATC HIMOND CRVTURE THMON IDETECT LINWDT' 1' FMERIT PKREFL WDTREFL') if(nc.eq.3) write(2,4323) 4323 FORMATC HIMOND ISAMPLE CRVTURE IDETECT LINWDT' 1' FMERIT PKREFL WDTREFL') if(nc.eq.4)write(2,4324) 4324 FORMATC HIMOND CRVTURE THMON IDETECT LINWDT' 1' FMERIT PKREFL WDTREFL ISAM') if(nc.eq.5)write(2,4325) 4325 FORMATC HIMOND CRVTURE THMON IDETECT LINWDT' 1' FMERIT PKREFL WDTREFL') if(nc.eq.6)write(2,4326) 4326 FORMATC DANGLE IFULL ISAMPLE IDETECT LINWDT' 1' VERTCRV1 DZS FMERIT') if(nc.eq.7)write(2,4327) 4327 FORMATC DANGLE ISAMPLE IDETECT LINWDT' IFULL 1' VERTCRV2 PKREFL FMERIT') if(nc.eq.8)write(2,4328) IDET' 4328 FORMATC TRUEMOS PKREFL WDREFL INTRFL ISAMPLE 1' LNWDTH FMERIT') if(nc.eq.9)write(2,4329) 4329 FORMATC TRUEM0S2 PKREFL2 WDREFL2 INTRFL2 ISAMPLE IDETECT' 1' LNWDTH FMERIT') if(nc.eq.lO)write(2,433O) 4330 FORMATC WDREFL IFULL ISAMPLE IDETECT LINWDT' 1' THICKNM PKREFL FMERIT') if(nc.eq.ll)write(2,4331) 4331 FORMATC DANGLE IFULL ISAMPLE IDETECT LINWDT', 1' THICKNM2 PKREFL2 FMERIT') if(nc.eq.l2)write(2,4332) 4332 FORMATC DANGLE IFULL ISAMPLE IDETECT LINWDT' 1' WIDTHH PKREFL FMERIT') if(nc.eq.l3)write(2,4333) 4333 FORMATC DANGLE SAMPLEDIM ISAMPLE IDETECT LINWDT' 1' CRVTURE1 PKREFL1 FMERIT') if(nc.eq.l4)write(2,4334) 4334 FORMATC DANGLE IFULL ISAMPLE IDETECT LINWDT'

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1' ALFASAM PKREFL1 FMERIT') if(nc.eq.l5)write(2,4335) 4335 FORMATC DANGLE ISAMPLE IDETECT LINWDT WDETECT', 1' RDETECT PKREFL1 FMERIT') if(nc.eq.l6)writo(2,4336) 4336 FORMATC DANGLE IFULL ISAMPLE IDETECT LINWDT', 1' S0LLER2 PKREF1 FMERIT') if(nc.oq.l7)write(2,4337) 4337 FORMATC'WAVELGTH PKREFL WDRFLM INTRFLM FMERIT IDETECT', 1' LINWDT TETHAB CRVTDRE1') if(nc.eq.20)write(2,43370) 43370 FORMATC'WAVELGTH PKREFL IFULL ISAMPLE FMERIT IDETECT', 1' LINWDT TETHAB VCRVTURE') ilCnc.eq.l8)WRITEC2,4338) 4338 FORMATC' DANGLE IFULL ISAMPLE IDETECT LINWDTM', 1' LINWDTP CRVTURE PKREFL') if(nc.eq.l9)WRITEC2,4339) 4339 FORMATC' MSDIST DTS DZS ISAMPLE IDETECT', 1' LINWDTP CRVTURE PKREFL') WRITEC3.130) 130 F0RMATC//20X,'EXPERIMENTAL CONFIGURATION'/) WRITE(3,26)Y0,TEMP 26 FORMATC51,'THERMAL NEUTRON FLUX AT THE SOURCE:',Ell.3,' NEUTRONS/C 1M**2/SEC'/5X,'SOURCE SPECTRUM TEMPERATURE:',F11.0,' KELVIN') IFCNGUIDE.NE.0)WRITEC3,27) 27 FORMATC5X,'NEUTRON GUIDE EXIT AS A VIRTUAL SOURCE') IFCNS0U.Eq.0)WRITEC3,131)DIAS0U IF(NSOU.NE.0)WRITEC3,11131)WSOU,HSOU 131 FORMAT(5X,'SOURCE OF CIRCULAR SHAPE, DIAMETER:',F6.2,' CM'/) 11131 FORMATC5X,' SOURCE OF RECTANGULAR SHAPE, WIDTH:',F6.2, 1' CM, HEIGHT:',F6.2,' CM'/) IF(NFM.LT.O)GO TO 7000 WRITE(3,7010) 7010 FORMAT(5X,'COARSE COLLIMATOR BETWEEN SOURCE AND MONOCHROMATOR') WRITEC3,7020)VLSM 7020 F0RMATC5X,'DISTANCE SOURCE - COLLIMATOR ENTRANCE:',F8.1,' CM') IFCNFM.GT.O)GO TO 1131 A1=2.*HDM1 A2=2.*HDM2 WRITE(3,1132)A1,A2 1132 FORMATC5X,'CIRCULAR COLLIMATOR, DIAMETER',F5.2,' CM AT ENTRANCE,' 1.F5.2,' CM AT EXIT') GO TO 1134 1131 A1=2.*HDM1 A2=2.*HDM2 A3=2.*VDM1 A4=2.*VDM2 WRITEC3,1133)A1,A2,A3,A4 1133 FORMAT(5X,'RECTANGULAR COLLIMATOR OF WIDTHS:',F6.2,' AT ENTRANCE A 1ND',F6.2,' AT EXIT'/5X,'COLLIMATOR HEIGHT AT ENTRANCE:',F9.2,' CM, 2 AT EXIT:',F9.2,' CM') 1134 WRITEC3,132)VLCANM 7000 IFCNFS.LT.0)G0 TO 8000

29 WRITE(3,8050) 8050 FORMAT(51,'COARSE COLLIMATOR BETWEEN NONOCHRONATOR AND SAMPLE') 8150 WRITE(3,8200)VLMS 8200 FORMAT(51,'DISTANCE FROM MONOCHROMATOR CENTER TO COLLIMATOR ENTRAN 1CE:',F8.1,' CM') IF(NFS.GT.O)GO TO 8300 A1=2.*HDS1 A2=2.*HDS2 WRITE(3,1132)A1,A2 60 TO 8400 8300 A1=2.*HDS1 A2=2.*HDS2 A3=2.*VDS1 A4=2.*VDS2 WRITE(3,1133)A1,A2,A3,A4 8400 WRITE(3,132)VLCANS 132 FORMAT(5X,'COLLIMATOR LENGTH:',13X,F8.2,' CM'/) 8000 IF(NFD.LT.O)GO TO 7100 WRITE(3,7030) 7030 FORMAT(5X,'COARSE COLLIMATOR BETWEEN SAMPLE AND DETECTOR') WRITE(3,7040)VLSD 7040 F0RMAT(5X,'DISTANCE FROM SAMPLE CENTER TO COLLIMATOR ENTRANCE:' ,F6 1.1,' CM') IF(NFD.GT.O)GO TO 7050 A1=2.*HDD1 A2=2.*HDD2 WRITE(3,1132)A1,A2 GO TO 7070 7050 A1=HDD1*2. A2=2.*HDD2 A3=2.*VDD1 A4=2.*VDD2 WRITE(3,1133)A1,A2,A3,A4 7070 WRITE(3,132)VLCAND 7100 IF(IC.Eq.l)GO TO 3200 WRITE(3,133)VL0 133 FORMAT(5X,'DISTANCE SOURCE - FIRST CRYSTAL:',F7.1,' CM') WRITE(3,134)VL01 134 FORMAT(5X,'DISTANCE BETWEEN CRYSTALS: \F6.1,' CM') WRITE(3,1367)VL1 1367 F0RMAT(5X,'DISTANCE SECOND CRYSTAL - SAMPLE:' ,F6.1,' CM') GO TO 3485 3200 WRITE(3,3300)7L0 3300 FORMAT(5X,'DISTANCE SOURCE - MONOCHROMATOR:',F7.1,' CM') WRITE(3,3475)VL1 3475 FORMAT(5X,'DISTANCE MONOCHROMATOR - SAMPLE:',F7.1,' CM') 3485 WRITE(3,137)VL2 137 FORMAT(5X,'DISTANCE SAMPLE - DETECTOR: \F7.1,' CM') IF(ALPHAM(l).NE.0.)WRITE(3,1140)ALPHAM(l) IF(BETAM(l).NE.0.)WRITE(3,139)BETAM(l) 139 FORMAT(51,'VERTICAL SOLLER BEFORE MONOCHROMATOR >, 1F6.2,' MINUTES') 1140 FORMAT(5X,'SOLLER COLLIMATOR BEFORE MONOCHROMATOR',

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1F6.2,' MINUTES') IF(ALPHAH(2).NE.0.)WRITE(3,1396)ALPHAM(2) IF(BETAM(2).NE.0.)WRITE(3,1399)BETAM(2) 138 FORMAT(51,'SOLLER COLLIMATDR BEFORE DETECTOR, ', 1F6.2,' MINUTES') 1399 FORMAT(5X,'VERTICAL SOLLER BEFORE SAMPLE ', 1F6.2,' MINUTES') IF(ALPHAM(3).NE.0.)WRITE(3,138)ALPHAM(3) IF(BETAM(3).NE.0.)WRITE(3,1395)BETAM(3) 1395 FORMAT(5X,'VERTICAL SOLLER BEFORE DETECTOR ', 1F6.2,' MINUTES') 1396 FORMAT(5X,'SOLLER COLLIMATOR BEFORE SAMPLE, ', 1F6.1,' MINUTES') IF(NSAM.NE.O)GO TO 111 WRITE(3,112)DIASAM,HSAM,ABSAM 112 F0RMAT(5X,'CYLINDRICAL SAMPLE, DIAMETER',F5.2,' CM, HEIGHT', 1F6.2,' CM'/,5X,'SAMPLE ABSORPTION COEFFICIENT:',F11.3,' CM**-1'/) GO TO 115 111 WRITE(3,113)WSAM.THSAM.HSAM.ABSAM 113 FORMAT(SX,'PLATE SAMPLE, WIDTH \FS.2,' CM, THICKNESS \F5.2 1,' CM, HEIGHT '.F5.2,' CM'/5X,'ABSORPTION COEFFICIENT:',F6.3, 2'CM**-1'/) 115 IF(NDET.Eq.l)WRITE(3,121)WDET,HDET 121 F0RMAT(5X,'RECTANGULAR DETECTOR WINDOW, WIDTH '.F6.2,' CM, 1 HEIGHT\F6.2,' CM'/) IF(NDET.Eq.0)WRITE(3,122)DIADET 122 F0RMAT(5X,'CIRCULAR DETECTOR WINDOW, DIAMETER \F6.2,'CM '/) RETURN END

C C C

SUBROUTINE SDATA2(NN) READS THE INPUT DATA TO BE DEPOSITED IN THE COMMON BLOCK C0IN7; COMPUTES WORKING PARAMETERS TO BE DEPOSITED IN THE COMMON C0IN6; PRINTS MONOCHROMATOR PARAMETERS AND GENERAL GEOMETRY DATA CHARACTERS CRYTI(31) COMMON/NOMIVA/QO,EIO,VKI,SLAMDI COMMON/GMON/WLGM,RH,RMH,RMV,DETHI,DETVI,DETHO,DETVO,DYS,DZS, 1SMO(3,3),VM0(2,2) ,ST(3,3),VT(2,2),RM0N(3,3) COMMON/VERTIC/ETAVM.ETAVM2,ANRM,ANRM2 COMMON/DIMENS/NSOU,WSOU,HSOU,DIASOU,WMON,THMON,HMON,WM0N2,THM0N2, 1HM0N2,NSAM,WSAM,THSAM,HSAM,DIASAM,NDET,WDET,HDET,DIADET COMMON/MONOCH/TETAMD,HIMOND ,ROHM,ROVM,ETAM,NGRADM,PM,PMO,RKINM, 1RLAMM,WLAMM,BVIB,RAMPLV C0MM0N/M0N0CH2/TETAD2,HIM0D2,R0HM2,R0VM2,ETAM2,NGRAM2,PM2,PM02, 1RKINM2.RLAMM2.WLAHH2 COMMON/VOCO/VO(16)/KVCO/KV(16) COMMON/SETUP/VLO,VLO1,VL1,VL2 COMMON/COARSE/NFM,VLCANM,VLSM,HDM1,HDM2,VDM1,VDM2, 1 NFS,VLCANS,VLMS,HDS1,HDS2,VDS1,VDS2, 2 NFD,VLCAND,VLSD,HDD1,HDD2,VDD1,VDD2 COMMON/INDEX/ND,NCYCLE,IC,ICO,NCR1,NCR2,NOPT,KOP,NWR,NC C0MM0N/S0LLER/NGOIDE,ALPHAH(3),BETAM(3).ALPHA(3),BETA(3) COMM0N/CRYTI/CRYTI/CRYD/CRYD(31)/D0KOVD/DOKOVD(31)/SV/SVMO(31)

31 l/C0MID/C0MIU(155)/P0ISS/P0ISS(31) COMMON /FLX/YO.TEMP COMMON/SAMPLE/TETASD,HISAMD,ABSAM,ALFASAM COMMON/ANGLE/TETAM.HIMON,HIM0N2.TETAM2,TETAS,HISAM,ETAHEF,ETAVEF, 1ETHEF2.ETVEF2 COMMON /CTANTS/PI,TDR,TMR,R8LN2.HSQOVM,GAMACR RIGHT=PI/2. IF(NGRADM.GT.1)R0VM=R0HM IF(NGRADM.EQ.4)R0VM=-R0HM*P0ISS(NCR1) IF(IC.EQ.1)GO TO 55 IF(NGRAM2.GT.1)R0VM2=R0HM2 IF(NGRAM2.EQ.4)R0VM2=-R0HM2*P0ISS(NCR2) 55 IF(NN.NE.O)GO TO 12345 C READ THE MONOCHROMATOR BRAGG ANGLE AND THE SCATTERING ANGLE, C BOTH OF THEM IN DEGREES, TRIGONOMETRIC SENSE. FOR DOUBLE CRYSTAL C MONOCHROMATORS TETAMD IS THE FIRST CRYSTAL BRAGG ANGLE. READ(1,2)TETAMD,TETASD

NEXT PAGB(Si left BLA

Summary Although neutron diffraction is a basic and relatively simple technique and should be available at a neutron source, it is not possible to perform neutron diffraction measurements at IRI at this moment. Until recently a neutron diffractometer with a relatively small flux at the sample position and a relaxed resolution (designed for liquid diffraction) was operated at IRI. Due to the modest neutron source intensity and the relatively old design (flat monochromator and single detector) this diffractometer was outdated. However, at a contemporary reactor source an instrument to perform neutron diffraction experiments cannot be missed This study shows that thanks to recent developments in neutron diffraction optics it is possible to increase the flux, to enhance the resolution and to get a better flexibility. If also the number of detectors is increased or a position-sensitive detector is used the performance can be increased at least a thousand fold A preliminary design is given to indicate how this gain can be realized.

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Bibliography [1] G.E. Bacon, 'Neutron diffraction', (Clarendon press, Oxford, 1975), K. Sko and D.L. Price, 'Methods of experimental physics', Vol. 23, (Academic Press, London and New York, 1987), J. Baruchel, J. Hodeau, M.S. Lehmann, J. Regnard and C. Schlenker, 'Neutron and synchrotron radiation for condensed matter studies', Vol. 1, (Springer-Verlag, Berlin, 1993). [2] M. Popovici, W.B. Yelon, R. Berliner, A.D. Stoica, I. Ionita and R. Law, Nucl. Instrum. and Methods in Phys. Res. A 338 (1994) 99. [3] A. Magerl and V. Wagner, 'Focussing Bragg optics', Nucl. Instrum.. and Methods in Phys. Res. A 338 (1994) 1-150. [4] P.P.A.M. Arends, P. Verkerk, L.A. de Graaf, I.N. de Schepper and A.A. van Well, 'FOXS, Proposal for a high count rate time-of-flight spectrometer at the 2 MW reactor in Delft', (IRI, 1995).

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