Voyager In Space

 

Galaxy Banner Image
VOYAGER

Voyager LECP Data Analysis Handbook

 

Instrument Modeling Reports

 

An Analysis of the Performance of the Magnetic Deflection System
 in the Voyager Low Energy Charged Particle Experiment

 

by Sheela Shodhan

 

E.11 TRAJ2PT

 

****************************************************************************
*                       PROGRAM TRAJ1PHI                                   *
* PURPOSE : THIS IS THE MAIN PROGRAM IN A SET OF ROUTINES TO FOLLOW  THE   *
*           PARTICLE TRAJECTORIES INSIDE THE SENSOR SUBSYSTEM, IDENTIFY THE*
*           IMPACT ON SURFACES AND COUNT THOSE THAT ESCAPE THE SENSOR SUB  *
*          -SYSTEM.                                                        *
* ROUTINES TO BE LINKED : TRAJ2PT,CHECHITSEN1,FDMOD1,TIMER,TRACKSUB1,      *
*           TRAJRT2BDET                                                    *
* DESCRIPTION :(1)TRAJ2PT:THIS IS THE MAIN ROUTINE MAINLY USED TO PLOT THE *
*           PARTICLE TRAJECTORIES INSIDE THE SENSOR SUBSYSTEM. IT LOOPS    *
*           OVER THE USER SPECIFIED POLAR ANGLE (THETA) AND THE AZIMUTHAL  *
*           ANGLE (PHI).                                                   *
* FOR DETAILED EXPLANATIONS, PLEASE SEE THE COMMENTS IN THE ROUTINES THEMSE*
* -LVES.                                                                   *
*         (2)CHECHITSEN1:THIS CONTAINS THE SET OF ROUTINES TO DETERMINE WHE*
*           -THER THE LINE-SEGMENT HAS HIT ANY OF THE POLYGON SURFACES OF  *
*           THE SENSOR OR NOT.                                             *
*         (3)FDMOD1:CALCULATES THE MAGNETIC FIELD AT THE GIVEN POINT IN SPA*
*           -CE.                                                           *
*         (4)TIMER:SHORT ROUTINE TO DETERMINE THE C.P.U. TIME REQUIRED TO  *
*           RUN THIS PROGRAM.                                              *
*         (5)TRACKSUB1:CONTAINS A SET OF ROUTINES TO PERFORM VARIOUS TASKS.*
*         (6)TRAJRT2BDET:CONTAINS THE DIFFERENTIAL EQUATION SOLVER DHPCG   *
*           AND A SET OF ROUTINES THAT ARE NEEDED BY IT.                   *
* VARIABLES :                                                              *
* INPUT :                                                                  *
* X0,Y0,Z0 : INITIAL POSITION OF THE PARTICLE (* 10**2 INCHES).            *
* EK : INCIDENT ELECTRON ENERGY (MEV).                                     *
* NPHI,NTHETA : THE NUMBER OF PHIs AND THETAs TO BE SCANNED.               *
* PHIMIN : THE MINIMUM AZIMUTHAL ANGLE AT WHICH SCANNING STARTS(DEGREES).  *
* PRMT : 1-D ARRAY THAT IS TO BE PASSED TO THE ROUTINE DHPCG               *
*        (1) INITIAL TIME, (2) FINAL TIME, (3)TIME STEP, (4) ERROR BOUND.  *
*        (* 10**-8 SECONDS).                                               *
* STEPHI,STEPTHETA : INTERVALS AT WHICH AZIMUTHAL AND POLAR ANGLES ARE SCAN*
*                   -NED RESPECTIVELY (DEGREES).                           *
* THETAMIN : (DEGREES)MINIMUM POLAR ANGLE AT WHICH THETAs ARE SCANNED.     *
* OUTPUT:                                                                  *
* NPAS : NUMBER OF PARTICLES THAT PASS THE SENSOR SUBSYSTEM.               *
* *.E* : FILE THAT RECORDS THE ANGLES AT THE DETECTOR,AND ANGLES,POSITIONS *
*      AND VELOCITIES AT THE APERTURE, OF THE ESCAPING TRAJECTORIES.       *
* *.E*IN, *.E*OUT, *.E*OUTVEL : FILES OF ANGLES AT THE DETECTOR,APERTURE   *
*      AND ANGLES COMPUTED FROM Vx,Vy and Vz AT THE APERTURE RESPECTIVELY. *
* *.E*** : FILE FOR EACH PARTICLE CONTAINING ITS POSITION COORDINATES AT   *
*        EVERY POINT IN THE TRAJECTORY. THIS FILE CAN BE USED TO PLOT THE  *
*        TRAJECTORY OF THE PARTICLE INSIDE THE SENSOR SUBSYSTEM.           *
* OTHERS:                                                                  *
* NHIT : INDICATES WHETHER THE PARTICLE IS LOST OR NOT-THETAs ARE SCANNED  *
*       UNITL THE PARTICLE ESCAPES FROM THE SENSOR SUBSYSTEM (NHIT=2).     *
* PAS : 1-D ARRAY, (1)-(4)POLAR & AZIMUTHAL ANGLES AT THE DETECTOR AND AT  *
*      THE APERTURE,(5)-(10) x,y,z,Vx,Vy,Vz OF THE ESCAPING PARTICLE.      *
* QMC : q/mc CONSTANT (C.G.S. UNITS).                                      *
* QMCP : QMC * sqrt(1 - (v/c)^2) TO TAKE CARE OF THE RELATIVITIC MASS.     *
* PHI,THETA : INITIAL AZIMUTHAL AND POLAR ANGLE AT THE DETECTOR SURFACE.   *
* V : VELOCITY OF THE PARTICLE FOR GIVEN ENERGY EK.                        *
* Y : 1-D ARRAY TO BE PASSSED TO THE ROUTINE DHPCG                         *
*    (1)-(3) POSITION COORDINATES, (4)-(6) VELOCITY COMPONENTS.            *
* PLEASE NOTE : (1)ROUTINES TRACKSUB1 AND TRACKSUB5 ARE BASICALLY THE SAME *
* EXCEPT THAT THE SUBROUTINE 'PASSOUTPUT' IN TRACKSUB5 INCLUDES PASS5.CMN  *
* WHILST 'PASSOUTPUT' IN TRACKSUB1 INCLUDES PASS.CMN. BESIDES, 'PASSOUTPUT'*
* IN TRACKSUB5 ALSO WRITES IN THE FILE *.E*OUTVEL, POLAR ANGLES AND AZIMUTH*
* AL ANGLES AT THE APERTURE OF THE ESCAPING PARTICLE CALULATED FROM THE VEL*
* -OCITY COMPONENTS Vx,Vy AND Vz OF THE PARTICLE.                          *
* THE DIFFERENCE BETWEEN PASS5.CMN AND PASS.CMN IS THAT IN THE FORMER THE  *
* DIMENSION OF THE ARRAY 'PAS' IS MUCH LARGER.                             *
* (2)DIFFERENCES BETWEEN TRAJRT2BDET AND TRAJRT2BDET5 ARE:                 *
* AT EVERY FEW STEPS OF THE TRAJECTORY, FORMER WRITES THE POSITION COORDINA*
* -TES IN THE FILE *.E***, SO THAT THE TRAJECTORY CAN BE PLOTTED.          *
* FORMER INCLUDES DIFFERENTIAL EQUATION SOLVER DHPCG WHILE THE LATTER DOES *
* NOT. FORMER WRITES THE POSITION AND VELOCITY COMPONENTS AT EVERY FEW STEP*
* -S IN A FILE 'TRAJSH.DAT' WHILE THE LATTER DOES NOT. LATTER ALSO COMPUTES*
* THE OUTGOING ANGLES FROM THE VELOCITY COMPONENTS OF THE PARTICLE AS IT   *
* ESCAPES THE APERTURE, THE FORMER DOES NOT. TRAJRT2BDET INCLUDES FILE     *
* 'PASS.CMN' WHILE TRAJRT2BDET5 INCLUDES FILE 'PASS5.CMN'.                 *
* (3) THUS, TRAJ2PT IS MAINLY SUITED FOR PLOTTING THE TRAJECTORIES OF THE  *
* PARTICLES AND FOR SHORT SCANS OVER THE ANGLES WHILST TRAJ6PT IS FOR LONG *
* SCANS, TO COUNT THE NUMBER OF PARTICLES THAT PASS IN ORDER TO COMPUTE THE*
* GEOMETRIC FACTOR FOR VARIOUS ENERGIES.                                   *
****************************************************************************
 
      PROGRAM TRAJ1PHI
      IMPLICIT NONE
      CHARACTER*72 FNAME,FNAME1,FNAME2,FNAME3
      INTEGER I,I1,IHLF,J,MAXE,NCOUNT,NDIM,NHIT,NPHI,NTHETA,NU
      INTEGER NXK,NYK,NZK
      PARAMETER (MAXE=100)
      REAL*8 C,CON,ERRWT
      PARAMETER (CON=2.540005D0,NDIM=6)
      REAL*8 STEPHI,STEPTHETA,EK,ENEK,PHIMIN,EVELO,PHI(MAXE),
     & QMC,QMCP,
     & THETA(MAXE),THETAMIN,V,VX,VY,VZ
      REAL*8 AUX(16,NDIM),DERY(NDIM),PRMT(5),X0,Y(NDIM),Y0,Z0
      REAL CPUTIME,TIMER,ZTIM0
      INCLUDE 'PASS.CMN'
      COMMON /QMC/QMC
      COMMON /NCOUNT/NCOUNT,/NU/NU,/FNAME/FNAME,/NHIT/NHIT
      COMMON /FNAME1/FNAME1
      COMMON /FNAME2/FNAME2,FNAME3
      DATA C/2.998D0/,QMCP/0.175602D0/
      EXTERNAL FCT,OUTP
      ZTIM0=TIMER()
      
      CALL GEOM    
    
      OPEN(UNIT=7,FILE='TRAJSH.DAT',ACCESS='SEQUENTIAL',STATUS='NEW')
      WRITE(6,*) 'ENTER THE INITIAL COORDINATES OF THE e IN INCHES'
      READ(5,*) X0,Y0,Z0
C     TO ENTER QUANTITIES FOR PRMT
      WRITE(6,*) 'ENTER LOWER BOUND ON TIME (t=0)'
      READ(5,*) PRMT(1)
      WRITE(6,*) 'ENTER THE UPPER BOUND ON TIME'
      READ(5,*) PRMT(2)
      WRITE(6,*) 'ENTER THE TIME STEP'
      READ(5,*) PRMT(3)
      WRITE(6,*) 'ENTER THE ERROR BOUND'
      READ(5,*) PRMT(4)
   
      WRITE(6,*) 'ENTER THE ENERGY OF THE PARTICLE IN MEV'
      READ(5,*) EK
      ENEK=IDINT(1000.0D0*EK)  
      NXK=IDINT(-100000.0D0*X0)
      NYK=IDINT(-100000.0D0*Y0)
      NZK=IDINT(100000.0D0*Z0)
      ENCODE (17,60,FNAME1)NXK,NYK,NZK,IDINT(ENEK)
      OPEN(UNIT=8,STATUS='NEW',ACCESS='SEQUENTIAL',FILE=FNAME1)
      ENCODE (19,110,FNAME2)NXK,NYK,NZK,IDINT(ENEK)
      OPEN(UNIT=1,STATUS='NEW',ACCESS='SEQUENTIAL',FILE=FNAME2)
      ENCODE (20,120,FNAME3)NXK,NYK,NZK,IDINT(ENEK)
      OPEN(UNIT=2,STATUS='NEW',ACCESS='SEQUENTIAL',FILE=FNAME3)
      V = EVELO(EK)          !COMPUTE V FOR THIS ENERGY OF e
      QMC = -QMCP*DSQRT(1 - (V/C)**2)  
      WRITE (6,*) 'ENTER MIN. THETA,NO. OF STEPS,DEL THETA'
      READ (5,*) THETAMIN,NTHETA,STEPTHETA
      WRITE (6,*) 'ENTER MIN. PHI,NO. OF STEPS,DEL PHI'
      READ (5,*) PHIMIN,NPHI,STEPHI
      WRITE (8,70) EK,V
      WRITE (8,80) THETAMIN,NTHETA,STEPTHETA
      WRITE (8,90) PHIMIN,NPHI,STEPHI
      WRITE (8,20) PRMT(1),PRMT(2),PRMT(3),PRMT(4)
      WRITE (8,*)
      WRITE (8,95) X0,Y0,Z0
      WRITE (1,130) 
      WRITE (2,140)
C     TO CONVERT FROM INCHES TO CMS. 
      X0 = X0 * CON
      Y0 = Y0 * CON
      Z0 = Z0 * CON
      WRITE (8,100) X0,Y0,Z0
      WRITE (8,*)
      DO I=1,NTHETA
       THETA(I)=THETAMIN + DFLOAT(I-1)*STEPTHETA
      END DO
      DO I=1,NPHI
       PHI(I)=PHIMIN + DFLOAT(I-1)*STEPHI
      END DO
 
      NPAS=0 
      DO J=1,NTHETA
       DO I=1,NPHI
        ENCODE (23,50,FNAME)NXK,NYK,NZK,IDINT(ENEK),
     &                          IDINT(THETA(J)),IDINT(PHI(I))
        OPEN(UNIT=4,STATUS='NEW',ACCESS='SEQUENTIAL',FILE=FNAME)
        NCOUNT = 0        
        NU = 1
        WRITE(7,05) I
        WRITE(7,10) EK,V,THETA(J),PHI(I)
        WRITE(7,20) PRMT(1),PRMT(2),PRMT(3),PRMT(4)
        WRITE(7,30)
        WRITE(4,05) I
C       TO COMPUTE THE VELOCITY PROJECTIONS Vx,Vy,Vz
        CALL VELOPROJ(V,VX,VY,VZ,THETA(J),PHI(I))
   
        WRITE(6,*) ' THETA( ',J,')',THETA(J),' PHI( ',I,')',PHI(I)
C       TO INITIALISE THE INITIAL VALUES 
        Y(1) = X0
        Y(2) = Y0
        Y(3) = Z0
        Y(4) = VX
        Y(5) = VY
        Y(6) = VZ
        ERRWT = 1.0D0/6.0D0
        DO I1=1,NDIM
         DERY(I1) = ERRWT
        END DO
 
        CALL DHPCG(PRMT,Y,DERY,NDIM,IHLF,FCT,OUTP,AUX)
        IF (NHIT .EQ. 2) THEN
         PAS(NPAS,1) = THETA(J)
         PAS(NPAS,2) = PHI(I)
        END IF
        WRITE(7,40)
        WRITE(4,40)
        WRITE(6,*) 
        WRITE(6,*) ' IHLF NO. OF BISECTIONS OF STEP: ',IHLF
        WRITE(6,*) 'TOTAL NO. OF POINTS IN THE TRAJECTORY: ',NU-1
       END DO
      END DO 
      CALL PASSOUTPUT
      WRITE(6,*) 'NPAS:',NPAS
      CPUTIME=TIMER()-ZTIM0
      WRITE(6,*) 'C.P.U. TIME: ',CPUTIME
      WRITE(1,40)
      WRITE(2,40)
 05   FORMAT(1X,I3)
 10   FORMAT(1X,'ENERGY(in mev)',D10.3,2X,'VELOCITY(*10+10)',F12.5,2X,
     & 'THETA(in deg.)',F10.3,2X,'PHI(in deg.)',F10.3)
 20   FORMAT(1X,'INITIAL TIME(*10-08)',F12.6,2X,'FINAL TIME(*10-08)',
     & F12.6,2X,'INITIAL STEP(*10-08)',F14.8,1X,'ERROR BOUND',F19.12)
 30   FORMAT(4X,'T(-08)',10X,'X(+02)',10X,'Y(+02)',10X,'Z(+02)',10X,
     & 'VX(+10)',10X,'VY(+10)',10X,'VZ(+10)',10X,'(V+10)')
 40   FORMAT(X,'---*---*---*--- END OF ENERGY ---*---*---*---')
 50   FORMAT (I3,I3,I4,'.E',I5,I3,I3)
 60   FORMAT (I3,I3,I4,'.E',I5)
 70   FORMAT (1X,'ENERGY(in mev)',D10.3,2X,'VELOCITY(*10+10)',F12.5)
 80   FORMAT (1X,'INITIAL THETA(in deg.)',F10.2,2X,'NO. OF STEPS',
     & I5,2X,'DEL THETA',F10.2)
 90   FORMAT (1X,'INITIAL PHI  (in deg.)',F10.2,2X,'NO. OF STEPS',
     & I5,2X,'DEL PHI  ',F10.2)
 95   FORMAT (1X,'STARTING POSITION(in in.)',2X,'X(+02)',D14.7,
     & 2X,'Y(+02)',D14.7,2X,'Z(+02)',D14.7)
100   FORMAT (1X,'STARTING POSITION(in cm.)',2X,'X(+02)',D14.7,
     & 2X,'Y(+02)',D14.7,2X,'Z(+02)',D14.7)
110   FORMAT (I3,I3,I4,'.E',I5,'IN')
120   FORMAT (I3,I3,I4,'.E',I5,'OUT')
130   FORMAT(1X,'POLAR & AZIMUTHAL ANGLES AT THE DETECTOR')
140   FORMAT(1X,'POLAR & AZIMUTHAL ANGLES AT THE APERTURE')
      CLOSE(1)
      CLOSE(2)
      CLOSE(7)
      CLOSE(4)      
      CLOSE(8)
      STOP
      END
C-----------------------------------------------------------------------------
C-----------------------------------------------------------------------------            

 

 

Return to thesis table of contents. 

Return to Voyager LECP Data Analysis Handbook Table of Contents.
Return to Fundamental Technologies Home Page.


Updated 8/9/19, Cameron Crane

VOYAGER 1 ELAPSED TIME

--:--:--:--
Days: Hours: Minutes: Seconds

*Since official launch
September 5, 1977, 12:56:00:00 UTC

VOYAGER 2 ELAPSED TIME

--:--:--:--
Days: Hours: Minutes: Seconds

*Since official launch
August 20, 1977, 14:29:00:00 UTC

QUICK FACTS

Manufacturer: Voyagers 1 and 2 were built in the Jet Propulsion Laboratory in Southern California.

Mission Duration: 40+ years have elapsed for both Voyager 1 and Voyager 2 (both are ongoing).

Destination: Their original destinations were Saturn and Jupiter. Their current destination is interstellar space.