/[PAMELA software]/gpamela/gpspe/gpudiffusion.F
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Annotation of /gpamela/gpspe/gpudiffusion.F

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Revision 3.2 - (hide annotations) (download)
Tue May 8 15:02:39 2007 UTC (17 years, 7 months ago) by bottai
Branch: MAIN
CVS Tags: v4r14, v4r12, v4r13
Changes since 3.1: +8 -4 lines
 correction of a bug concerning Lorentz anglangle drift

1 bottai 3.1 SUBROUTINE GPUDIFFUSION(IACT,TRAPAR,NUMVOL,DELOSS,STEP,ITYPAR)
2     ********************************************************************************
3     *
4     * To perform diffusion of electron and holes bunch inside the silicon
5     * detectors of the spectrometer
6     *
7     * Variables definition:
8     * IN:
9     * IACT, integer specifing the action to be taken. It is the INWVOL
10     * variable in GCTRAK common
11     * 0: Track is inside a volume
12     * 1: Entering a new volume or is a new track
13     * 2: Track is exiting current volume
14     * TRAPAR, track parameter, is the VECT vector in GCTRAK common (x,y,z..)
15     * NUMVOL, integr array of numbers identifying the DETECTOR (NUMBV di gustep)
16     *
17     * DELOSS, energy loss in the step (GeV)
18     * ITYPAR, id particella della traccia(vhit(9) che sarà iparspe nell'entupla finale)
19     * OUT:
20     *
21     *
22     * Called by: GPUSPE
23     * Author: Elena Taddei, 04/08/2005 , S. Bottai 30/01/06
24     *
25     *************************************************************************************
26     #include "gpstripspe.inc"
27     #include "gpgeo.inc"
28     #include "gpgene.inc"
29 bottai 3.2 #include "gpkey.inc"
30 bottai 3.1
31     INTEGER IACT,NUMVOL(20)
32     REAL DELOSS, TRAPAR(7),xyzspa(3),VPOS(3),xyzspac(3)
33     REAL BMAGNET(3),STRPOSL(3),STRPOSG(3)
34     INTEGER ONCE
35     DATA ONCE /0/
36     SAVE ONCE
37    
38     IF(NUMVOL(1).NE.0) THEN
39     NSPEPLANE=NUMVOL(1)
40     ELSE IF(NUMVOL(1).EQ.0) THEN
41     NSPEPLANE=6
42     ENDIF
43    
44    
45     VPOS(1)=TRAPAR(1)-STEP/2.*TRAPAR(4)
46     VPOS(2)=TRAPAR(2)-STEP/2.*TRAPAR(5)
47     VPOS(3)=TRAPAR(3)-STEP/2.*TRAPAR(6)
48    
49    
50     delossmev=deloss*1000.
51    
52    
53     call gmtod(VPOS,xyzspa,1)
54     zup=TSPA(3)-xyzspa(3)
55     zdown=TSPA(3)+xyzspa(3)
56    
57 bottai 3.2
58 bottai 3.1 nearstripx=nearstx(xyzspa(1),xyzspa(2))
59     if(nearstripx.ne.0) then
60    
61    
62     dx=xyzspa(1)-xstrip(nearstripx)
63    
64     ****************************************************************************
65     *
66     * X-view strips collect holes, Y-view strips collect electrons.
67     * Both charge carriers are shifted due to the magnetic field.
68     * The shift for holes is significant, because it is
69     * orthogonal to read-out strips.
70     * A correction for this effect is introduced.
71     * v is along -Z; B is along -Y --> shift is along -X
72     *
73     *****************************************************************************
74 bottai 3.2 IF(FFIELD.NE.0) THEN
75 bottai 3.1 CALL GUFLD(VPOS,BMAGNET)
76    
77     c
78     c to be checked
79     c
80 bottai 3.2 xshift=xyzspa(1)+zdown*hallmob*1.e-4*BMAGNET(2)/10.
81     IF(NSPEPLANE.EQ.6) xshift=xyzspa(1)-
82 bottai 3.1 + zdown*hallmob*1.e-4*BMAGNET(2)/10.
83    
84 bottai 3.2 else
85     xshift=xyzspa(1)
86     endif
87 bottai 3.1
88     *
89     * Now widths of Gaussian functions can be calculated by means of
90     * the routine sigmadiffus, that gives sigma in m --> *100 --> cm
91     *
92     sigxi=amax1(0.00014,100.*sigmadiffus(zdown)) !perchè min=1.4 um?
93    
94     *
95     * Sharing of the charge on strips.
96     * erf(x) from cernlib computes the (signed) integral of the gaussian
97     * function from -x to x (sigma=sqrt(1./2.), x0=0). If you have gaussian
98     * function with x0=a, sigma=b, area between -x and x is obtainable by the
99     * following formula:
100     *
101     * A = erf((x-a)/(sqrt(2.)*b)) A>0 if x-a>0; A<0 if x-a<0
102     *
103     * erfc(x) (ALWAYS > 0) computes the complementary function, i.e.
104     * 2*integral between x and +infinity
105     * --> 0.5*erfc(x)=area of the gaussian between x to +inf.
106     *
107    
108    
109     NSTRIPLOW=MIN(23,NEARSTRIPX)
110     NSTRIPHIGH=MIN(15,NSTRIPX-NEARSTRIPX)
111    
112     DO J=(NEARSTRIPX-NSTRIPLOW+8),(NEARSTRIPX+NSTRIPHIGH-6)
113     xqdivjm1=xstrip(j)-pitchx/2.
114     xqdivj=xstrip(j)+pitchx/2.
115     qfract=0.5*erfc((xqdivjm1-xshift)/(sqrt(2.)*sigxi))
116     + -0.5*erfc((xqdivj-xshift)/(sqrt(2.)*sigxi))
117    
118     proxtanti(NSPEPLANE,numvol(2),j)=
119     + proxtanti(NSPEPLANE,numvol(2),j)+delossmev*qfract
120     IF(GLOBSTRIPX(NSPEPLANE,NUMVOL(2),J).EQ.0.) THEN
121     STRPOSL(1)=XSTRIP(J)
122     STRPOSL(2)=0.
123     STRPOSL(3)=0.
124     CALL GDTOM(STRPOSL,STRPOSG,1)
125     GLOBSTRIPX(NSPEPLANE,NUMVOL(2),J)=STRPOSG(1)
126     ENDIF
127    
128     enddo
129     endif
130    
131    
132    
133    
134    
135     nearstripy=nearsty(xyzspa(1),xyzspa(2))
136     if(nearstripy.ne.0) then
137    
138     dy=xyzspa(2)-ystrip(nearstripy)
139    
140    
141     sigyi=amax1(0.00023,100.*sigmadiffus(zup ) ) !perchè min=2.3 um?
142    
143     *
144     * The standard deviation on the Y side is increased
145     * according to a parabolic behaviour + a constant term near p-stop
146     *
147     py=pitchy
148     if (abs(dy).lt.abs((py-psy2)/2.)) then
149     sigyi=sigyi-psy1*(dy**2)+(py-psy2)*psy1*abs(dy)
150     else
151     sigyi=sigyi-psy1*(((py-psy2)/2.)**2)
152     + +(py-psy2)*psy1*abs((py-psy2)/2.)
153     endif
154    
155    
156     NSTRIPLOW=MIN(7,NEARSTRIPY)
157     NSTRIPHIGH=MIN(7,NSTRIPY-NEARSTRIPY)
158     do j=(NEARSTRIPY-NSTRIPLOW+1),(NEARSTRIPY+NSTRIPHIGH)
159     yqdivjm1=ystrip(j)-py/2.
160     yqdivj=ystrip(j)+py/2.
161     qfract=0.5*erfc((yqdivjm1-xyzspa(2))/(sqrt(2.)*sigyi))
162     + -0.5*erfc((yqdivj-xyzspa(2))/(sqrt(2.)*sigyi))
163    
164     proytanti(NSPEPLANE,numvol(2),j)=
165     + proytanti(NSPEPLANE,numvol(2),j)+delossmev*qfract
166    
167     IF(GLOBSTRIPY(NSPEPLANE,NUMVOL(2),J).EQ.0.) THEN
168     STRPOSL(1)=0.
169     STRPOSL(2)=YSTRIP(J)
170     STRPOSL(3)=0.
171     CALL GDTOM(STRPOSL,STRPOSG,1)
172     GLOBSTRIPY(NSPEPLANE,NUMVOL(2),J)=STRPOSG(2)
173     ENDIF
174    
175     enddo
176    
177     endif
178    
179    
180    
181    
182    
183     END
184    
185     *
186     * ////////////////////////////////////////////////////////////////////////////////////////
187     *
188     real function sigmadiffus(zp)
189     *********************************************************************
190     * Width of the Gaussian function due to diffusion spread is found.
191     * x,y,z : where charge is generated (position in given in cm)
192     * As output standard deviation (m) due to diffusion in silicon
193     * Diffusion coefficients are proportional to mobility: D=kTm/q,
194     * where m is mobility: this is true in the Internatinal System
195     * of units, not in GCS. We compute this quantity in the
196     * I.S. (renormalitation for m --> cm has been taken into account:
197     * zpsi=zp/100. ! cm --> m
198     * Efield=Efield*100. ! V/cm --> V/m --> 10^-4 )
199     * WARNING!! Sigma is independent on the carrier mobility m,
200     * because hdiff = c*m but time = c/m. As a consequence,
201     * sigma is independent on the dopant concentration.
202     * E-h pairs created are mostly confined in a tube of about 1 um diameter.
203     **********************************************************************
204     #include "gpstripspe.inc"
205    
206     zm=zp/100. ! cm --> m
207     Evm=ebias*100. ! V/cm --> V/m
208    
209     vdepl=55.
210     vappl=70.
211     thick=3.e-4
212     *
213     * timemu = collection time * mobility
214     *
215     timemu=abs(-(thick**2/(2.*vdepl))*log(1-(2*vdepl*zm)/
216     + ((vdepl+vappl)*thick)))
217    
218     sigmadiffus=sqrt((2.*boltis*temperature*timemu)/eis)+dsigma
219    
220     return
221     end
222    
223     * ////////////////////////////////////////////////////////////
224    
225    
226    
227     real function xstrip(j)
228     cv parameter.........
229     #include "gpstripspe.inc"
230     parameter (jlastx=2042)
231     parameter (xlast=5.333/2.-0.07315)
232     parameter (jfirstx=8)
233     parameter (xfirst=0.07315-5.333/2.)
234    
235     px=pitchx
236     py=pitchy
237     if(j.lt.jfirstx.or.j.gt.jlastx) then
238     write(6,*) 'error , stripx=',j,'not existing'
239     xstrip=-1.e10
240     endif
241     xstrip=(j-jfirstx)*px+xfirst
242    
243     end
244    
245    
246     real function ystrip(j)
247     cv parameter.........
248     #include "gpstripspe.inc"
249     parameter (jlasty=1024)
250     parameter (ylast=7./2.-0.09855)
251     parameter (jfirsty=1)
252     parameter (yfirst=0.0985-7./2.)
253    
254     px=pitchx
255     py=pitchy
256     if(j.lt.jfirsty.or.j.gt.jlasty) then
257     write(6,*) 'error , stripy=',j,'not existing'
258     ystrip=-1.e10
259     endif
260     ystrip=(j-jfirsty)*py+yfirst
261    
262     end
263    
264    
265    
266     function nearstx(x,y)
267     cv parameter.........
268     #include "gpstripspe.inc"
269     parameter (jlastx=2042)
270     parameter (xlast=5.333/2.-0.07315)
271     parameter (jfirstx=8)
272     parameter (xfirst=0.07315-5.333/2.)
273     parameter (y1xstrip=0.1117-7./2.)
274     parameter (y2xstrip=7./2.-0.09)
275    
276     px=pitchx
277     py=pitchy
278     if(x.lt.(xfirst-px/2.).or.x.gt.(xlast+px/2.)) then
279     nearstx=0
280     return
281     endif
282     if(y.lt.y1xstrip.or.y.gt.y2xstrip) then
283     nearstx=0
284     return
285     endif
286    
287     nearstx=int((x-xfirst)/px)+jfirstx
288     if( (x-xstrip(nearstx)).gt.(px/2.) ) nearstx=nearstx+1
289    
290    
291     end
292    
293     function nearsty(x,y)
294     cv parameter.........
295     #include "gpstripspe.inc"
296     parameter (jlasty=1024)
297     parameter (ylast=7./2.-0.09855)
298     parameter (jfirsty=1)
299     parameter (yfirst=0.0985-7./2.)
300    
301     parameter (x1ystrip=0.0894-5.333/2.)
302     parameter (x2ystrip=5.333/2.-0.1221)
303    
304     px=pitchx
305     py=pitchy
306     if(y.lt.(yfirst-py/2.).or.y.gt.(ylast+py/2.)) then
307     nearsty=0
308     return
309     endif
310     if(x.lt.x1ystrip.or.x.gt.x2ystrip) then
311     nearsty=0
312     return
313     endif
314    
315     nearsty=int((y-yfirst)/py)+jfirsty
316     if( (y-ystrip(nearsty)).gt.(py/2.) ) nearsty=nearsty+1
317    
318    
319    
320     end

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