Determining wire-phi correspondance

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Test for θ=20 and ϕ=1

All previous quantities where calculated for θ=20 and do not depend on the angle ϕ. The quantities that do change

xD1=rD1 cos(ϕ)=.5901cos(1))=.5900myD1=rD1cos(ϕ)=.5901sin(1))=.0103zD1=rD1cot(θ)=.5901cot(20)=1.6212 m
xD2=rD2cos(ϕ)=1.3055cos(1))=1.3053myD2=rD2sin(ϕ)=1.3055sin(1))=.0228zD2=rD2cot(θ)=1.3055cot(20)=3.5868 m


xP=2.53cos(ϕ)(cot(θ)+cos(ϕ)cot(65)=2.53cos(1))(cot(20)+cos(1))cot(65)=0.7869
yP=2.53sin(ϕ)(cot(θ)+cos(ϕ)cot(65)=2.53sin(1))(cot(20)+cos(1))cot(65)=.0137
zP=2.53cot(θ)(cot(θ)+cos(ϕ)cot(65)=2.53cot(20)(cot(20)+cos(1))cot(65)=2.1624


D2P=(xD2xP)2+(yD2yP)2+(zD2zP)2=(1.30530.7869)2+(.0228.0137)2+(3.58682.1624)2=(.5184)2+(.0091)2+(1.4244)2=1.51582872713 m


D1P=(xPxD1)2+(yPyD1)2+(zPzD1)2=(0.7871.5900)2+(.0137.0103)2+(2.16241.6212)2=(.1971)2+(.0034)2+(.5412)2=.575983862621 m


x_1^'=\frac{r_2^{'2}-r_1^{'2}}{4ae}-ae=\frac{1.5158^{'2}-.5758^{'2}}{4(1.0459)(.4497)}-(1.0459)(.4497)=.575\ \text{m}


Using the pythagorean theorem

y=.5762.5752=.03 m


The two possible answers denote shifting to the left on right on the y axis. We take the direction of positive and negative to be the same as the sign convention for the angle phi starting on the x axis and shifting positive clockwise. A shift of 1 degree in phi at theta equal to 20 degrees only results in a small change in the x and y. This changes depending on the angles.

Function for the change in x' in the detector frame for change in ϕ and constant θ in the lab frame

D2P=(xD2xP)2+(yD2yP)2+(zD2zP)2


D1P=(xPxD1)2+(yPyD1)2+(zPzD1)2


x_1^'=\frac{((x_{D2}-x_P)^2+(y_{D2}-y_P)^2+(z_{D2}-z_P)^2)-((x_P-x_{D1})^2+(y_P-y_{D1})^2+(z_P-z_{D1})^2)}{4ae}-ae
xD1=rD1 cos(ϕ)yD1=rD1cos(ϕ)zD1=rD1cot(θ)


xD2=rD2cos(ϕ)yD2=rD2sin(ϕ)zD2=rD2cot(θ)


xP=2.53cos(ϕ)(cot(θ)+cos(ϕ)cot(65)


yP=2.53sin(ϕ)(cot(θ)+cos(ϕ)cot(65)


zP=2.53cot(θ)(cot(θ)+cos(ϕ)cot(65)


x_1^'=\frac{((x_{D2}-x_P)^2+(y_{D2}-y_P)^2+(z_{D2}-z_P)^2)-((x_P-x_{D1})^2+(y_P-y_{D1})^2+(z_P-z_{D1})^2)}{4ae}-ae


x_1^'=\frac{x_{D2}^2-2x_Px_{D2}+x_P^2+y_{D2}^2-2y_Py_{D2}+y_P^2+z_{D2}^2-2z_Pz_{D2}+z_P^2-x_P^2+2x_Px_{D1}-x_{D1}^2-y_P^2+2y_Py_{D1}-y_{D1}^2-z_P^2+2z_Pz_{D1}-z_{D1}^2}{4ae}-ae


x_1^'=\frac{(x_{D2}^2+y_{D2}^2)-(x_{D1}^2+y_{D1}^2)+z_{D2}^2-z_{D1}^2-2x_P(x_{D2}-x_{D1})-2y_P(y_{D2}-y_{D1})-2z_P(z_{D2}-z_{D1})}{4ae}-ae


x_1^'=\frac{(r_{D2}^2)-(r_{D1}^2)+cot^2(\theta)(r_{D2}^2-r_{D1}^2)-2x_P(x_{D2}-x_{D1})-2y_P(y_{D2}-y_{D1})-2z_P(z_{D2}-z_{D1})}{4ae}-ae


Expressing this as functions of ϕ and non-differentiable constants


x_1^'=\frac{c_1+c_2-2x_P(\phi)x_{D2}(\phi)+2x_P(\phi)x_{D1}(\phi)-2y_P(\phi)y_{D2}(\phi)+2y_P(\phi)y_{D1}(\phi)-2z_P(\phi)c_3}{4c_4}-c_4

Differentiating with respect to ϕ

xD1=rD1cos(ϕ)˙xD1=rD1sin(ϕ)


yD1=rD1sin(ϕ)˙yD1=rD1cos(ϕ)


xD2=rD2cos(ϕ)˙xD2=rD2sin(ϕ)


yD2=rD2sin(ϕ)˙yD2=rD2cos(ϕ)


xP=2.52934271645cos(ϕ)cot(θ)+cos(ϕ)cot(65)˙xP=2.52934271645cot(θ)sin(ϕ)(cos(ϕ)cot(65+cot(θ))2


yP=2.52934271645sin(ϕ)cot(θ)+cos(ϕ)cot(65)˙yP=1.7206+2.52934271645cos(ϕ)cot(θ)(cos(ϕ)cot(65)+cot(θ))2


zP=2.52934271645cot(θ)cot(θ)+cos(ϕ)cot(65)˙zP=1.7206cot(θ)sin(ϕ))(cos(ϕ)cot(65)+cot(θ))2
dx11dϕ=24c4ddϕ(xP(ϕ)xD2(ϕ))+24c4ddϕ(xP(ϕ)xD1(ϕ))24c4ddϕ(yP(ϕ)yD2(ϕ))+24c4ddϕ(yP(ϕ)yD1(ϕ))2c34c4ddϕzP(ϕ)


dx11dϕ=24c4((˙xP(ϕ)xD2(ϕ)+xP(ϕ)˙xD2(ϕ))(˙xP(ϕ)xD1(ϕ)+xP(ϕ)˙xD1(ϕ))+(˙yP(ϕ)yD2(ϕ)+yP(ϕ)˙yD2(ϕ))(˙yP(ϕ)yD1(ϕ)+yP(ϕ)˙yD1(ϕ))+c3˙zP(ϕ))

Function for the wire number in the detector frame for change in ϕ and constant θ in the lab frame

Using the expression for wire number n in terms of θ for the detector mid-plane where ϕ=0:

n=957.412tan(θ)+2.14437+430.626

We can use the inverse of this function to find the neighboring wire's corresponding angle theta

θ4.49876+0.293001n+0.000679074n23.57132×106n3


θ(n±1)4.49876+0.293001(n±1)+0.000679074(n±1)23.57132×106(n±1)3


We also know what the x' function must follow dependent on phi in the detector plane

x_1^'=\frac{((x_{D2}-x_P)^2+(y_{D2}-y_P)^2+(z_{D2}-z_P)^2)-((x_P-x_{D1})^2+(y_P-y_{D1})^2+(z_P-z_{D1})^2)}{4ae}-ae


x_1^'=\frac{(r_{D2}^2)-(r_{D1}^2)+cot^2(\theta)(r_{D2}^2-r_{D1}^2)-2x_P(x_{D2}-x_{D1})-2y_P(y_{D2}-y_{D1})-2z_P(z_{D2}-z_{D1})}{4ae}-ae


xD1=rD1 cos(ϕ)yD1=rD1cos(ϕ)zD1=rD1cot(θ)


xD2=rD2cos(ϕ)yD2=rD2sin(ϕ)zD2=rD2cot(θ)


xP=2.53cos(ϕ)(cot(θ)+cos(ϕ)cot(65)


yP=2.53sin(ϕ)(cot(θ)+cos(ϕ)cot(65)


zP=2.53cot(θ)(cot(θ)+cos(ϕ)cot(65)
rD1=RLower Dandelincos(θ)=(aeΔa)tan(65)cos(θ)rD2=RLower Dandelincos(θ)=(ae+Δa)tan(65)cos(θ)

We can take this point to be the x axis intercept and use the fact that each wire is titled by 6 degrees to the horizontal in the plane of the detector to create an equation

xwire n=tan(6)y+xn0

where the initial wire and x' position at the given theta is represented by n0


This equation can be solved for a hypothetical wire 0, which will allow the wire number to be the multiplicative factor for the change from the starting position.


xn=1sin4.79=2.52934sin110.21xn=1=.2252


Since each wire is separated by .01337 meters


.2252.01337=.2117=xn=0


Each wire becomes an equation of the form,

xwire n=tan(6)y+.2117+.01337 n

This agrees with CED simulation



DC geom.png

Setting up Mathematica for DC Theta-Phi Isotropic Cone

File:FirstPass.pdf


File:SecondPass.pdf