1. WARP: fitting gamma signals
Graphic and Minuit-based program able to reconstruct time and amplitude of two signals produced by gamma events in WARP detector.
Readout of input data file (binary structured) (Riccardo).
Graphics (Andrea).
Minuit strategy (Rinaldo):
catch the highest signal (usually the secondary)
fix highest signal parameters and look for smaller signal (usually the primary).
free all parameters and try overall fit.
Compute fit amplitudes and time.

2. Signal-shape fit by an empirical function (two peaks only)
9 free parameters

3. Definitions
Secondary amplitude
Base line
Primary amplitude

4. Good event first step

5. Good event last step
c2 = 0.72

6. Bad event first step

7. Bad event last step
Rejected by
c2 = 20.3

8. Bad event first step

9. Bad event last step accepted by c2 = 2.1
This topology is the only contribution to the contamination of the sample.
A strategy could be defined to cut this kind of events.

10. Normalized c2 distribution

11. Efficiency and contamination
Very preliminary
Total efficiency in reconstructing
good events: %
Total efficiency in rejecting
bad events: %
It results a 12 % contamination of bad events in the accepted sample

12. Time performances The production rate of DARK program is about:
5.0 event / minute
(could be improved)
7200 events / day

13. Preliminary results 50000 triggers

14. 50000 triggers
c2 cut

16. Secondary spectrum - data 4000

17. Comparison manual vs fit amplitudes

18. Comparison bet. fit and manual secondary spectrum

19. Conclusion Improvements :
Measure with higher accuracy (statistics) efficiency and contamination,
Improve the speed of the program
Study a strategy for “neutron” signals.