MuTau Database Update:
Added the new results from Block 15, 16 and 17
Goro Sato
09 Nov 2004
The current mutau table has the mutau products only for 14 blocks including Block B, which is no longer be in the detector plane but replaced by Block 17. This is becuase of the incomplete data sets for the last three blocks (15, 16 and 17) due to the limited calibration time. However, here we try to perform the muatu-fit with limited data sets and included the results into the mutau database.
Block 16:
Data sets used for mutau-fit:
-
- blk_16_co57_100_20_0_0_021217_1_corr2.root
- blk_16_co57_150_20_0_0_021217_2_corr2.root
- blk_16_co57_200_0_0_021217_1_corr2.root
It was unknown that the last file was obtained at 0 degree or 20 degrees. But,
according to the block calibration log notebooks, it was found to be a mistype of the file name and obtained at 20 degrees. Now, we perform the mutau-fit for Block 16.
Block 15, 17
Data sets used for mutau-fit:
-
- blk_15_co57_100_10_0_0_021217_21_corr2.root
- blk_15_co57_150_10_0_0_021217_1_corr2.root
- blk_15_co57_200_10_0_0_021217_2_corr2.root
- blk_17_co57_100_10_0_0_030206_3_corr2.root
- blk_17_co57_150_10_0_0_030206_2_corr2.root
- blk_17_co57_200_10_0_0_030206_1_corr2.root
There is no complete data set at 20 degrees for these two blocks. However, accoding to the detailed study for the temperature dependence of mutau products, we found that the mutau for electrons decreases by ~4% while the mutau for holes decreases by 14% from 20 to 10 degrees on average. These numbers are relatively small in the large variation of mutau products, which is more than 1 order of magnitude. Therefore we performed mutau-fitting for these two blocks using the data at 10 degrees.
MuTau Distributions
Three types of mutau plots are shown below before and after including the new reuslts from Block 15, 16 and 17.
Color maps for mutau for electrons and holes:
The measured mutaus are plotted in color scale at each an actual detector position. The result from Block 15 and 16 are inserted at right and bottom corner. The result from Block 17 replaced Block B at array position 8.
MuTau cross-plot:
The crossplot is divied into 9-by-7 groups with equal intervals in log-scale, showing the numbers of detectors included in each grid as percentage of the total with a criteria of >0.1%. The distribution slightly moves to the left and downward.
| MuTau for Electrons | MuTau for Holes | MuTau Cross-Plot |
|---|
| Before |  |  |  |
| After |  |  |  |
Model comparison
To develop a spectral model for the entire CdZnTe array, we utilize the 36(35) most populated groups in the mutau cross-plot. We first calculate a mutau-model for each populated group and sum them up, using a fraction of detectors as a wieght.
Here we compare the difference between using the mutau distributions before and after including the three blocks.
We can see a slight change of the spectral shape for Co-57 spectrum. A small portion (1 % at peak) is removed from the the 122 keV peak, and re-distributed into the low energy tail.
MuTau Database
The updated FITS file which contains 32K sets of mutau products is available at:
/local/data/gcn4a/block_cal/mutau/MuTauTable_041027.fits
The updated list of the most populated mutau groups is also available at :
/local/data/gcn4a/block_cal/mutau/mutau_table_041027.txt
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