Changeset 6268
- Timestamp:
- 02/04/05 19:48:06 (20 years ago)
- Location:
- trunk/MagicSoft/TDAS-Extractor
- Files:
-
- 1 added
- 1 edited
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trunk/MagicSoft/TDAS-Extractor/Algorithms.tex
r6113 r6268 299 299 possibilities are offered: 300 300 301 \begin{ enumerate}301 \begin{description} 302 302 \item[Extraction Type Amplitude:\xspace] The amplitude of the spline maximum is taken as charge signal 303 303 and the (precisee) position of the maximum is returned as arrival time. This type is faster, since it 304 performs not spline intergraion 304 performs not spline intergraion. 305 305 \item[Extraction Type Integral:\xspace] The integrated spline between maximum position minus 306 306 rise time (default: 1.5 slices) and maximum position plus fall time (default: 4.5 slices) … … 310 310 is slower, but yields more precise results (see section~\ref{sec:performance}) . 311 311 The charge integration resolution is set to 0.1 FADC slices. 312 \end{ enumerate}312 \end{description} 313 313 314 314 The following adjustable parameters have to be set from outside: … … 422 422 \begin{eqnarray} 423 423 0&=&-\boldsymbol{g}^T\boldsymbol{B}^{-1}\boldsymbol{y} 424 425 424 +\boldsymbol{g}^T\boldsymbol{B}^{-1}\boldsymbol{g}\overline{E} 425 +\boldsymbol{g}^T\boldsymbol{B}^{-1}\dot{\boldsymbol{g}}\overline{E\tau} 426 426 \\ 427 427 0&=&-\dot{\boldsymbol{g}}^T\boldsymbol{B}^{-1}\boldsymbol{y} 428 429 428 +\dot{\boldsymbol{g}}^T\boldsymbol{B}^{-1}\boldsymbol{g}\overline{E} 429 +\dot{\boldsymbol{g}}^T\boldsymbol{B}^{-1}\dot{\boldsymbol{g}}\overline{E\tau} \ . 430 430 \end{eqnarray} 431 431 … … 434 434 \begin{equation} 435 435 \overline{E}(\tau) = \boldsymbol{w}_{\text{amp}}^T (\tau)\boldsymbol{y} \quad \mathrm{with} \quad 436 437 438 436 \boldsymbol{w}_{\text{amp}} 437 = \frac{ (\dot{\boldsymbol{g}}^T\boldsymbol{B}^{-1}\dot{\boldsymbol{g}}) \boldsymbol{B}^{-1} \boldsymbol{g} -(\boldsymbol{g}^T\boldsymbol{B}^{-1}\dot{\boldsymbol{g}}) \boldsymbol{B}^{-1} \dot{\boldsymbol{g}}} 438 {(\boldsymbol{g}^T \boldsymbol{B}^{-1} \boldsymbol{g})(\dot{\boldsymbol{g}}^T\boldsymbol{B}^{-1}\dot{\boldsymbol{g}}) -(\dot{\boldsymbol{g}}^T\boldsymbol{B}^{-1}\boldsymbol{g})^2 } \ , 439 439 \end{equation} 440 440 441 441 \begin{equation} 442 442 \overline{E\tau}(\tau)= \boldsymbol{w}_{\text{time}}^T(\tau) \boldsymbol{y} \quad 443 444 445 443 \mathrm{with} \quad \boldsymbol{w}_{\text{time}} 444 = \frac{ ({\boldsymbol{g}}^T\boldsymbol{B}^{-1}{\boldsymbol{g}}) \boldsymbol{B}^{-1} \dot{\boldsymbol{g}} -(\boldsymbol{g}^T\boldsymbol{B}^{-1}\dot{\boldsymbol{g}}) \boldsymbol{B}^{-1} {\boldsymbol{g}}} 445 {(\boldsymbol{g}^T \boldsymbol{B}^{-1} \boldsymbol{g})(\dot{\boldsymbol{g}}^T\boldsymbol{B}^{-1}\dot{\boldsymbol{g}}) -(\dot{\boldsymbol{g}}^T\boldsymbol{B}^{-1}\boldsymbol{g})^2 } \ . 446 446 \end{equation} 447 447 … … 462 462 \begin{equation} 463 463 \left(\boldsymbol{V}^{-1}\right)_{i,j} 464 465 464 =\frac{1}{2}\left(\frac{\partial^2 \chi^2(E, E\tau)}{\partial \alpha_i \partial \alpha_j} \right) \quad 465 \text{with} \quad \alpha_i,\alpha_j \in \{E, E\tau\} \ . 466 466 \end{equation} 467 467 … … 470 470 \begin{equation}\label{of_noise} 471 471 \sigma_E^2=\boldsymbol{V}_{E,E} 472 473 472 =\frac{\dot{\boldsymbol{g}}^T\boldsymbol{B}^{-1}\dot{\boldsymbol{g}}} 473 {(\boldsymbol{g}^T \boldsymbol{B}^{-1} \boldsymbol{g})(\dot{\boldsymbol{g}}^T\boldsymbol{B}^{-1}\dot{\boldsymbol{g}}) -(\dot{\boldsymbol{g}}^T\boldsymbol{B}^{-1}\boldsymbol{g})^2} \ . 474 474 \end{equation} 475 475 … … 478 478 \begin{equation}\label{of_noise_time} 479 479 E^2 \cdot \sigma_{\tau}^2=\boldsymbol{V}_{E\tau,E\tau} 480 481 480 =\frac{{\boldsymbol{g}}^T\boldsymbol{B}^{-1}{\boldsymbol{g}}} 481 {(\boldsymbol{g}^T \boldsymbol{B}^{-1} \boldsymbol{g})(\dot{\boldsymbol{g}}^T\boldsymbol{B}^{-1}\dot{\boldsymbol{g}}) -(\dot{\boldsymbol{g}}^T\boldsymbol{B}^{-1}\boldsymbol{g})^2} \ . 482 482 \end{equation} 483 483 … … 496 496 497 497 498 For an IACT there are two types of background noise. On the one hand, there is the constantly present electronics noise, 499 on the other hand, the light of the night sky introduces a sizeable background noise to the measurement of Cherenkov photons from air showers. 500 501 The electronics noise is largely white, uncorrelated in time. The noise from the night sky background photons is the superposition of the 502 detector response to single photo electrons following a Poisson distribution in time. Figure \ref{fig:noise_autocorr_AB_36038_TDAS} shows the noise 503 autocorrelation matrix for an open camera. The large noise autocorrelation in time of the current FADC system is due to the pulse shaping with a 504 shaping constant of 6 ns. 498 For an IACT there are two types of background noise. On the one hand, there is the constantly present 499 electronics noise, 500 on the other hand, the light of the night sky introduces a sizeable background noise to the measurement of 501 Cherenkov photons from air showers. 502 503 The electronics noise is largely white, uncorrelated in time. The noise from the night sky background photons 504 is the superposition of the 505 detector response to single photo electrons following a Poisson distribution in time. 506 Figure \ref{fig:noise_autocorr_allpixels} shows the noise 507 autocorrelation matrix for an open camera. The large noise autocorrelation in time of the current FADC 508 system is due to the pulse shaping with a shaping constant of 6 ns. 505 509 506 510 In general, the amplitude and time weights, $\boldsymbol{w}_{\text{amp}}$ and $\boldsymbol{w}_{\text{time}}$, depend on the pulse shape, the … … 521 525 \includegraphics[totalheight=7cm]{noise_autocorr_AB_36038_TDAS.eps} 522 526 \end{center} 523 \caption[Noise autocorrelation.]{Noise autocorrelation matrix for open camera including the noise due to night sky background fluctuations.} 524 \label{fig:noise_autocorr_AB_36038_TDAS} 525 \end{figure} 526 527 527 \caption[Noise autocorrelation one pixel.]{Noise autocorrelation 528 matrix for open camera including the noise due to night sky background fluctuations for one single 529 pixel.} 530 \label{fig:noise_autocorr_1pix} 531 \end{figure} 532 533 \begin{figure}[htp] 534 \begin{center} 535 \includegraphics[totalheight=7cm]{noise_38995_smallNSB_all396.eps} 536 \includegraphics[totalheight=7cm]{noise_39258_largeNSB_all396.eps} 537 \includegraphics[totalheight=7cm]{noise_small_over_large.eps} 538 \end{center} 539 \caption[Noise autocorrelation average all pixels.]{Noise autocorrelation 540 matrix $\boldsymbol{B}$ for open camera and averaged over all pixels. The top figure shows $\boldsymbol{B}$ 541 obtained with camera pointing off the galactic plane (and low night sky background fluctuations). 542 The central figure shows $\boldsymbol{B}$ with the camera pointing into the galactic plane 543 (high night sky background) and the 544 bottom plot shows the ratio between both. One can see that the entries of $\boldsymbol{B}$ do not 545 simply scale with the amount of night sky background.} 546 \label{fig:noise_autocorr_allpixels} 547 \end{figure} 528 548 529 549 Using the average reconstructed pulpo pulse shape, as shown in figure \ref{fig:pulpo_shape_low}, and the … … 549 569 used in the MC simulations. The first weight $w_{\mathrm{time}}(t_0)$ is plotted as a function of the relative time $t_{\text{rel}}$ the trigger and the 550 570 FADC clock in the range $[-0.5,0.5[ \ T_{\text{ADC}}$, the second weight in the range $[0.5,1.5[ \ T_{\text{ADC}}$ and so on. A binning resolution 551 of $0.1 571 of $0.1\,T_{\text{ADC}}$ has been chosen.} \label{fig:w_time_MC_input_TDAS} 552 572 \end{figure} 553 573 … … 581 601 \begin{equation} 582 602 E=\sum_{i=i_0^*}^{i_0^*+n-1} w_{\mathrm{amp}}(t_i - \tau)y(t_{i+i_0^*}) \qquad 583 603 E \theta=\sum_{i=i_0^*}^{i_0^*+n-1} w_{\mathrm{time}}(t_i - \tau)y(t_{i+i_0^*}) \ . 584 604 \end{equation} 585 605 … … 808 828 %%% TeX-master: "MAGIC_signal_reco" 809 829 %%% TeX-master: "MAGIC_signal_reco" 830 %%% TeX-master: "MAGIC_signal_reco.te" 810 831 %%% End:
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