1. 30/8/05Lisa Fogarty Testing Detector Arrangements For 22 Na(p,γ) Experiment

2. 30/8/05Lisa Fogarty Aims Aim of this test was to minimise the high energy background seen in gamma ray spectra. Likely causes are cosmic rays and pile-up. Mostly worked on eliminating cosmic ray aspect.

3. 30/8/05Lisa Fogarty Detector Arrangements The main Ge detector was operated in anti-coincidence mode in varying arrangements. Four arrangements were used: 1.Ge detector alone 2.Ge detector with 3 (cylindrical) NaI scintillator detectors. 3.Ge detector with plastic scintillator paddle 4.Ge detector with plastic scintillator paddle covered with a Pb sheet.

4. 30/8/05Lisa Fogarty Detector Arrangements NaI ArrangementScintillator Paddle Arrangement

5. 30/8/05Lisa Fogarty Calibration

6. 30/8/05Lisa Fogarty Ge Detector Alone

7. 30/8/05Lisa Fogarty Ge Detector Alone Peak: 1274.5 keV ConstantErrorMeanErrorSigmaError 9.69e66.74e-8512.7332.96e-101.8967.39e-8 Peak Integral Error Background Integral ErrorRatio%Error 4.70e71.00e-764140.0121.39e-41.25

8. 30/8/05Lisa Fogarty Ge Detector with NaI Detectors

9. 30/8/05Lisa Fogarty Ge Detector with NaI Detectors Peak: 1274.5 keV ConstantErrorMeanErrorSigmaError 1.05e78.15e-8512.232.17e-101.1949.64e-8 Peak Integral Error Background Integral ErrorRatio%Error 3.13e71.25e-512620.0284.03e-52.81

10. 30/8/05Lisa Fogarty Ge Detector with Paddle

11. 30/8/05Lisa Fogarty Ge Detector with Paddle Peak: 1274.5 keV ConstantErrorMeanErrorSigmaError 6.28e61.77e-7512.573.42e-101.0731.70e-7 Peak Integral Error Background Integral ErrorRatio%Error 1.69e72.23e-710700.0316.34e-53.06

12. 30/8/05Lisa Fogarty Conclusions Significantly better performance using Ge detector in anti-coincidence mode. NaI detector anti-coincidence seems best at the moment. Investigate more arrangements using NaI detectors in different orientations to find optimal use. Possibly use a thicker scintillator paddle.