Hitfinding in E895 Mike Lisa

4/30/98


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Table of Contents

Hitfinding in E895 Mike Lisa

Outline

1D and 2D codes in broad strokes

Current status of codes

Operation of the 2D code

Running modes in 2D hitfinder

2D code- step 1: padwise correction

2D code- step 2: find clusters

2d code- step 3: Find peaks within each cluster

Note: can use a cut to see quickly if it is worthwhile to search for many peaks

We can cap number of peaks in a cluster by iterative threshold-raising.

2D code- step 4: initial guess at hit positions

2D code- Step 5: Fill hits table and save cluster structures for 2nd pass

Information for best possible fitting is built up.

The model of the data.

The model of the data

The model of the data

Crossing angles affect signal shape

2 passes allows fit of data with realistic model

Extracting final positions and dE by fitting to the model

Fitting the peaks - Initial guess

Fitting the peaks - Varying amplitudes

Fitting the peaks - varying position and amplitude (mode 6)

Width of 1-hit clusters indicates quality of model

Hit-by-hit comparison of widths of cluster patterns

Performance Measures of hitfinder-tracker-dE/dx chain

Visual Performance Measures of hitfinder-tracker-dE/dx chain

2 A×GeV data

4 A×GeV data

6 A×GeV data

8 A×GeV data

Summary of CPU times (hit+trk)

CPU of the second hitfitting pass

To do / to be understood

Author: Mike Lisa

Email: lisa@mps.ohio-state.edu

Home Page: vdgus1.mps.ohio-state.edu/~lisa/