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								accelerator/notes
									
									
									
									
									
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							| @ -0,0 +1,29 @@ | ||||
| notes: | ||||
| 
 | ||||
| from program Sim NRA | ||||
| 
 | ||||
| kinematic factor @ 2.000 ±0.001 MeV | ||||
| 
 | ||||
| 150 degrees | ||||
| 
 | ||||
|     Cu: 1885.05 ± 0.01 | ||||
|     Si: 1749.21 ± 0.01 | ||||
| 
 | ||||
| 
 | ||||
| 
 | ||||
| can find a ratio between the lithium and flourine cross-sections | ||||
| 
 | ||||
|     taking the ratio of the yields and cross-sections allows things like target thickness to drop out | ||||
| 
 | ||||
| what you're after: the yield and the cross-section are basically proportional to each other | ||||
| 
 | ||||
| in lab write-up | ||||
| 
 | ||||
| 
 | ||||
| 
 | ||||
| A big danger: | ||||
| 
 | ||||
|     Flourine curve very sensitive to different in energy of about .1, so this could change your ratio greatly | ||||
|     this would be a systematic error that caused an energy shift to explain wrong values | ||||
| 
 | ||||
|      | ||||
							
								
								
									
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								notes.R
									
									
									
									
									
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								notes.R
									
									
									
									
									
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							| @ -0,0 +1,102 @@ | ||||
| plot(y,xlab="Channel",ylab="Count",lwd=4,pch="-") | ||||
| lines(v[3]*exp(-1/2*(x-v[1])^2/v[2]^2),col=2,lwd=1.4) | ||||
| abline(v = 7813.63,col=4,lwd=1) | ||||
| axis(3,at=7813.63,"5.486 MeV") | ||||
| dev.print(pdf,"../report/calibration.pdf") | ||||
| 
 | ||||
| 
 | ||||
| Alpha Activity | ||||
| plot(data_4_2,xlab="Energy [MeV]",ylab="Count [Alpha Particles]",pch=".") | ||||
| minor.tick(nx=5,ny=2) | ||||
| abline(v = 5.631,col=2,lwd=1) | ||||
| axis(3,at=5.631,"5.6") | ||||
| abline(v = 5.323,col=2,lwd=1) | ||||
| axis(3,at=5.323,"5.3") | ||||
| dev.print(pdf,"../report/activity.pdf") | ||||
| 
 | ||||
| 
 | ||||
| 
 | ||||
| For Gaussian Fits: | ||||
| 
 | ||||
| ───────────── | ||||
| 
 | ||||
| x <- seq_along(y) | ||||
| 
 | ||||
| f <- function(par) | ||||
| { | ||||
|     m <- par[1] | ||||
|     sd <- par[2] | ||||
|     k <- par[3] | ||||
|     rhat <- k * exp(-0.5 * ((x - m)/sd)^2) | ||||
|     sum((y - rhat)^2) | ||||
| } | ||||
| 
 | ||||
| optim(c(15, 2, 1), f, method="BFGS", control=list(reltol=1e-9)) | ||||
| 
 | ||||
| ───────────── | ||||
| 
 | ||||
| I propose to use non-linear least squares for this analysis. | ||||
| 
 | ||||
| # First present the data in a data-frame | ||||
| tab <- data.frame(x=seq_along(y), y=y) | ||||
| #Apply function nls | ||||
| (res <- nls( y ~ k*exp(-1/2*(x-mu)^2/sigma^2), start=c(mu=7500,sigma=50,k=1) , data = tab)) | ||||
| 
 | ||||
| And from the output, I was able to obtain the following fitted "Gaussian curve": | ||||
| 
 | ||||
| v <- summary(res)$parameters[,"Estimate"] | ||||
| plot(y~x, data=tab) | ||||
| plot(function(x) v[3]*exp(-1/2*(x-v[1])^2/v[2]^2),col=2,add=T,xlim=range(tab$x) ) | ||||
| 
 | ||||
| 
 | ||||
| 
 | ||||
| 
 | ||||
| 
 | ||||
| 
 | ||||
| 
 | ||||
| Mirror Gumbel Distribution: | ||||
| 
 | ||||
| 
 | ||||
| (res <- nls( y ~ (1/beta)*exp((x-alpha)/beta - exp((x - alpha)/beta)), data=cal,start=c(alpha=7800,beta=1),control=list(minFactor=1/50000,maxiter=1000))) | ||||
| v <- summary(res)$parameters[,"Estimate"] | ||||
| plot(function(x) (1/v[2])*exp((x-v[1])/v[2] - exp((x - v[1])/v[2])),col=2,add=T,xlim=range(tab$x)) | ||||
| 
 | ||||
| 
 | ||||
| 
 | ||||
| 
 | ||||
| ────────────────────────────────────────────────────────────────────────── | ||||
| 
 | ||||
| ───────────── | ||||
| 
 | ||||
| File writing | ||||
| 
 | ||||
| write(x, file = "data", | ||||
|       ncolumns = if(is.character(x)) 1 else 5, | ||||
|       append = FALSE, sep = " ") | ||||
| 
 | ||||
| 
 | ||||
| dev.print(pdf,'filename.pdf') | ||||
| 
 | ||||
| 
 | ||||
| 
 | ||||
| 
 | ||||
| 
 | ||||
| ────────────────────────────────────────────────────────────────────────── | ||||
| 
 | ||||
| ───────────── | ||||
| Axis Formatting | ||||
| 
 | ||||
| # Add minor tick marks | ||||
| library(Hmisc) | ||||
| minor.tick(nx=n, ny=n, tick.ratio=n) | ||||
| 
 | ||||
| 
 | ||||
| 
 | ||||
| 
 | ||||
| 
 | ||||
| 
 | ||||
| ────────────────────────────────────────────────────────────────────────── | ||||
| 
 | ||||
| ───────────── | ||||
| Importing CSV | ||||
| 
 | ||||
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