Veto Efficiency for Neutral Particles

• March 24, 2005
• April 7, 2005
• April 14, 2005
• April 21, 2005

March 24, 2005

Middle of PbWO4: plots HYCAL hits in x, Veto hits in x, cluster x-y distribution, and the ration of Veto hits over HYCAL hits by x.

Bottom of PbWO4: plots HYCAL hits in x, Veto hits in x, cluster x-y distribution, and

Top of PbWO4: plots HYCAL hits in x, Veto hits in x, cluster x-y distribution, and

Comparison of the efficiency for middle(black), bottom(red), and top(green) position of HYCAL runs.

Next, I analyzed almost all of the PbWO4 calibration runs to see the y-position dependence of the efficiency.

April 7, 2005

Here I am showing the neutral efficiency for Veto counter 3 centered at x=-25cm. I am calculating the efficiency in three different ways - no cuts as shown above, fitting the counter's y spectrum with a gaussian peak on a gaussian background, and simple ADC cut on both top and bottom pmts. The data points are as follows:

• Red squares - No ADC cuts.
• Green triangles - ADC cut >1000.
• Blue triangle - subtracting background shape from y fit.
• Magneta open circles - integrating the peak gaussian shape from y fit.

Here are examples of the fits to the Veto y distributions for different runs. The left plot shows the combined fits. The middle plot shows the gaussian background fit(red) and the counts after subtraction(green). The right plot shows the gaussian peak fit(blue).

HYCAL y=-22

HYCAL y=-8

HYCAL y=15

HYCAL y=22

In this set of plots, I used a 3rd order polynomial fit to the background instead of the gaussian.

HYCAL y=15

April 14, 2005

Here I am showing the neutral efficiency for Veto counter 3 centered at x=-25cm with various ADC cuts. The data points are as follows:

• Black open circles - No ADC cuts.
• Red triangles - ADC cut >400.
• Green triangles - ADC cut >600.
• Blue squares - ADC cut >800.
• Magneta circles - ADC cut >1000.

For these two plots, I am showing the HYCAL x vs y (left) and the HYCAL x vs Veto y (right) for run 5353.

April 21, 2005

Now, I want to test ADC cuts on the charged-particle efficiency. Below are ADC spectra for counter #3(x=-25cm) from a pair production run(4865) and from a photon calibration run(5353).

Here are plots of HYCAL hits(top,left), veto hits(top,right), HYCAL x vs y(bottom,left), and veto efficiency(bottom,right) when the ADC cut is set at channel 400.

Here is a comparison of efficiency with 4 different ADC thresholds.

Black - ADC cut >400. Red - ADC cut >600. Green - ADC cut >800. Blue - ADC cut >1000.

For these two plots, I am showing the HYCAL x vs y (left) and the HYCAL x vs Veto y (right) for pair production run 4865.