Changeset 5763 for trunk/MagicSoft
- Timestamp:
- 01/10/05 11:35:54 (20 years ago)
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trunk/MagicSoft/TDAS-Extractor/Algorithms.tex
r5759 r5763 280 280 281 281 \begin{description} 282 \item[ Time Extraction Type:\xspace] The position of the maximum can be chosen or the283 position of the half maximum at the rising edge of the pulse (default). 284 \item[Charge Extraction Type:\xspace] The amplitude of the maximum can be chosen (default) or the285 integrated spline between maximum position minus rise time (default: 1.5 slices) and maximum position plus 286 fall time (default: 4.5 slices). The low-gain signal integrates half a slice more at the rising 287 falling part of the288 signal.282 \item[Charge Extraction Type:\xspace] The amplitude of the spline maximum can be chosen while the position 283 of the maximum is returned as arrival time. This type is fast. \\ 284 Otherwise, the integrated spline between maximum position minus rise time (default: 1.5 slices) 285 and maximum position plus fall time (default: 4.5 slices) is taken as signal and the position of the 286 half maximum is returned as arrival time (default). 287 The low-gain signal stretches the rise and fall time by a stretch factor (default: 1.5). This type 288 is slower, but more precise. The charge integration resolution is 0.1 FADC slices. 289 289 \item[Rise Time and Fall Time:\xspace] Can be adjusted for the integration charge extraction type. 290 290 \item[Resolution:\xspace] Defined as the maximum allowed difference between the calculated half maximum value and 291 291 the computed spline value at the arrival time position. Can be adjusted for the half-maximum time extraction 292 292 type. 293 \item[LoGainSignalStretch:\xspace] Can be adjusted to account for the bigger rise and fall time in the 294 low-gain as compared to the high gain pulses (default: 1.5) 293 295 \end{description} 294 296 … … 305 307 \item{The normalized signal shape has to be independent of the signal amplitude.} 306 308 \item{The noise properties have to be independent of the signal amplitude.} 309 \item{The noise auto-correlation matrix does not change its form significantly with time.} 307 310 \end{itemize} 308 311 … … 313 316 \end{equation} 314 317 315 where $b(t)$ is the time dependent noise distribution. For small time shifts $\tau$ the time dependence can be linearized by the use of a Taylor expansion: 318 where $b(t)$ is the time dependent noise distribution. For small time shifts $\tau$ (usually smaller than 319 one FADC slice width), 320 the time dependence can be linearized by the use of a Taylor expansion: 316 321 317 322 \begin{equation} \label{shape_taylor_approx} … … 350 355 \end{equation} 351 356 352 Taking into account that $\boldsymbol{B}$ is a symmetric matrix, this leads to the following two equations for the estimated amplitude $\overline{E}$ and the estimation for the product of amplitude and time offset $\overline{E\tau}$: 357 Taking into account that $\boldsymbol{B}$ is a symmetric matrix, this leads to the following 358 two equations for the estimated amplitude $\overline{E}$ and the estimation for the product of amplitude 359 and time offset $\overline{E\tau}$: 353 360 354 361 \begin{eqnarray} … … 369 376 370 377 371 Thus $\overline{E}$ and $\overline{E\tau}$ are given by a weighted sum of the discrete measurements $y_i$ with the digital filtering weights for the amplitude, $w_{\text{amp},i}$, and time shift, $w_{\text{time},i}$. 372 373 Because of the truncation of the Taylor series in equation (\ref{shape_taylor_approx}) the above results are only valid for vanishing time offsets $\tau$. For non-zero time offsets one has to iterate the problem using the time shifted signal shape $g(t-\tau)$. 378 Thus $\overline{E}$ and $\overline{E\tau}$ are given by a weighted sum of the discrete measurements $y_i$ 379 with the digital filtering weights for the amplitude, $w_{\text{amp},i}$, and time shift, $w_{\text{time},i}$. 380 381 Because of the truncation of the Taylor series in equation (\ref{shape_taylor_approx}) the above results are 382 only valid for vanishing time offsets $\tau$. For non-zero time offsets one has to iterate the problem using 383 the time shifted signal shape $g(t-\tau)$. 374 384 375 385 The covariance matrix $\boldsymbol{V}$ of $\overline{E}$ and $\overline{E\tau}$ is given by: 376 386 377 387 \begin{equation} 378 \left(\boldsymbol{V}^{-1}\right)_{i,j}=\frac{1}{2}\left(\frac{\partial^2 \chi^2(E, E\tau)}{\partial \alpha_i \partial \alpha_j} \right) \quad \text{with} \quad \alpha_i,\alpha_j \in {E, E\tau} \ .388 \left(\boldsymbol{V}^{-1}\right)_{i,j}=\frac{1}{2}\left(\frac{\partial^2 \chi^2(E, E\tau)}{\partial \alpha_i \partial \alpha_j} \right) \quad \text{with} \quad \alpha_i,\alpha_j \in \{E, E\tau\} \ . 379 389 \end{equation} 380 390 … … 388 398 389 399 \begin{equation}\label{of_noise_time} 390 E^2 \cdot \sigma_{\tau}^2=\boldsymbol{V}_{E ,E\tau}=\frac{{\boldsymbol{g}}^T\boldsymbol{B}^{-1}{\boldsymbol{g}}}{(\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} \ .400 E^2 \cdot \sigma_{\tau}^2=\boldsymbol{V}_{E\tau,E\tau}=\frac{{\boldsymbol{g}}^T\boldsymbol{B}^{-1}{\boldsymbol{g}}}{(\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} \ . 391 401 \end{equation} 392 402 … … 419 429 420 430 421 Using the average reconstructed pulpo pulse shape, see figure \ref{fig:pulpo_shape_low}, and the reconstructed noise autocorrelation matrix from a pedestal run with random triggers, the digital filter weights are computed. Figures \ref{fig:w_time_MC_input_TDAS} and \ref{fig:w_amp_MC_input_TDAS} show the parameterization of the amplitude and timing weights for the MC pulse shape as a function of the ... 422 431 Using the average reconstructed pulpo pulse shape, as shown in figure \ref{fig:pulpo_shape_low}, and the 432 reconstructed noise autocorrelation matrix from a pedestal run with random triggers, the digital filter 433 weights are computed. Figures \ref{fig:w_time_MC_input_TDAS} and \ref{fig:w_amp_MC_input_TDAS} show the 434 parameterization of the amplitude and timing weights for the MC pulse shape as a function of the ... 435 436 \par 437 \ldots {\textit{\bf MISSING END OF SENTENCE }} \ldots 438 \par 423 439 424 440 \begin{figure}[h!] … … 441 457 442 458 \begin{equation} 443 e_{i_0}=\sum_{i=i_0}^{i =i_0+n-1} w_{\mathrm{amp}}(t_i)y(t_{i+i_0}) \qquad (e\tau)_{i_0}=\sum_{i=i_0}^{i=i_0+n-1} w_{\mathrm{time}}(t_i)y(t_{i+i_0})459 e_{i_0}=\sum_{i=i_0}^{i_0+n-1} w_{\mathrm{amp}}(t_i)y(t_{i+i_0}) \qquad (e\tau)_{i_0}=\sum_{i=i_0}^{i_0+n-1} w_{\mathrm{time}}(t_i)y(t_{i+i_0}) 444 460 \end{equation} 445 461 … … 453 469 454 470 \begin{equation} 455 E=\sum_{i=i_0^*}^{i =i_0^*+n-1} w_{\mathrm{amp}}(t_i - \tau)y(t_{i+i_0^*}) \qquad E \theta=\sum_{i=i_0^*}^{i=i_0^*+n-1} w_{\mathrm{time}}(t_i - \tau)y(t_{i+i_0^*}) \ .471 E=\sum_{i=i_0^*}^{i_0^*+n-1} w_{\mathrm{amp}}(t_i - \tau)y(t_{i+i_0^*}) \qquad E \theta=\sum_{i=i_0^*}^{i_0^*+n-1} w_{\mathrm{time}}(t_i - \tau)y(t_{i+i_0^*}) \ . 456 472 \end{equation} 457 473 … … 478 494 %\frac{\sigma^2(b_i)}{\sigma_E^2} = \sum_{i=1}^{n}{g_i^2} - \frac{\sum_{i=1}^{n}{g_i \dot{g}_i}}{\sum_{i=1}^{n}{\dot{g}_i^2}} \ . 479 495 %\end{equation} 480 481 482 483 484 485 496 486 497 … … 490 501 \includegraphics[totalheight=7cm]{time_sliding.eps} 491 502 \end{center} 492 \caption[Digital filter weights applied.]{Digital filter weights applied to the recorded FADC time slices of one calibration pulse. The left plot shows the result of the applied amplitude weights $e(t_0)=\sum_{i=0}^{i=n-1} w_{\mathrm{amp}}(t_0+i \cdot T_{\text{ADC}})y(t_0+i \cdot T_{\text{ADC}})$ and the right plot shows the result of the applied timing weights $e\tau(t_0)=\sum_{i=0}^{i=n-1} w_{\mathrm{time}}(t_0+i \cdot T_{\text{ADC}})y(t_0+i \cdot T_{\text{ADC}})$ .} \label{fig:amp_sliding} 493 \end{figure} 494 495 496 Figure \ref{fig:shape_fit_TDAS} shows the FADC slices of a single MC event together with the result of a full fit of the input MC pulse shape to the simulated FADC samples together with the result of the numerical fit using the digital filter. 503 \caption[Digital filter weights applied.]{Digital filter weights applied to the recorded FADC time slices of 504 one calibration pulse. The left plot shows the result of the applied amplitude weights 505 $e(t_0)=\sum_{i=0}^{i=n-1} w_{\mathrm{amp}}(t_0+i \cdot T_{\text{ADC}})y(t_0+i \cdot T_{\text{ADC}})$ and 506 the right plot shows the result of the applied timing weights 507 $e\tau(t_0)=\sum_{i=0}^{i=n-1} w_{\mathrm{time}}(t_0+i \cdot T_{\text{ADC}})y(t_0+i \cdot T_{\text{ADC}})$ .} 508 \label{fig:amp_sliding} 509 \end{figure} 510 511 512 Figure \ref{fig:shape_fit_TDAS} shows the FADC slices of a single MC event together with the result of a full 513 fit of the input MC pulse shape to the simulated FADC samples together with the result of the numerical fit 514 using the digital filter. 497 515 498 516 … … 501 519 \includegraphics[totalheight=7cm]{shape_fit_TDAS.eps} 502 520 \end{center} 503 \caption[Shape fit.]{Full fit to the MC pulse shape with the MC input shape and a numerical fit using the digital filter.} \label{fig:shape_fit_TDAS} 504 \end{figure} 505 506 507 508 509 521 \caption[Shape fit.]{Full fit to the MC pulse shape with the MC input shape and a numerical fit using the 522 digital filter.} \label{fig:shape_fit_TDAS} 523 \end{figure} 510 524 511 525 … … 533 547 \includegraphics[totalheight=7cm]{probability_fit_0ns.eps} 534 548 \end{center} 535 \caption[Fit Probability.]{Probability of the fit with the input signal shape to the simulated FADC samples including electronics and NSB noise.} \label{fig:w_amp_MC_input_TDAS.eps} 549 \caption[Fit Probability.]{Probability of the fit with the input signal shape to the simulated FADC samples 550 including electronics and NSB noise.} \label{fig:w_amp_MC_input_TDAS.eps} 536 551 \end{figure} 537 552
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