1. Test of Electromagnetic Calorimeter modules for HADES, Mainz Sep.2009 A.Krása, F. Křížek, J. Pietraszko, Y. Sobolev, J. Stanislav, A. Reshetin, P. Tlustý purpose: measure the energy resolution of detector modules with various configurations in  beam at energy 0-1500 MeV test conditions and setup results

2. Test conditions 2 days of measurement: 1)E e- = 855 MeV, I  = 25 kHz 2) E e- = 1508 MeV, I  = 5 kHz Beam: - detectors were positioned in the secondary gamma beam with continuous energy distribution from 0 to primary electron beam energy, with intensity exponentially falling with increasing energy - unless stated otherwise, the detectors were hit in the centre of their front side, and the beam proceeded along their longitudinal axis - beam diameter at detector position – 6 mm diameter Trigger: OR of signals from 8 selected scintillators in electron tagger – giving events with 8 known gamma energies in range from 0 to energy of the electron beam

3. Detector modules numberlightguide, wrapping glass wrappingPMT 1lead glass, mylarmylarEMI9903KB 2lead glass, paperpaperEMI9903KB 3NOmylarEMI9903KB 4NOpaperEMI9903KB 5NOmylarHAMAMATSU1949 EMI9903KB: 1.5” tube from MIRAC (WA98) H1949: 2.5” tube from HADES Tofino Lead glass dimensions: 9.2 x 9.2 x 42 cm

4. Setup Trigger: OR of signals from 8 selected scintillators in electron tagger – giving events with 8 known gamma energies in range from 0 to energy of the electron beam Beam: detectors were positioned in the secondary gamma beam with continuous energy (intensity exponentially falling with increasing energy)

5. Setup Left up: test setup Left down: crew Right: detail with detectors, movable table and beam halo (looking in beam direction)

6. Results slide No. 1)Example of ADC spectra for E e- = 1508 MeV, module No.1 7 2)Energy resolution for run E e- = 855 MeV 8 3)Energy resolution for run E e- = 1508 MeV 9 4)Energy resolution for run E e- = 855, 1508 MeV and cosmics for modules No.1-5 10-14 5)Energy resolution as a function of HV 15 6)Energy resolution as a function of beam position 16 7)Energy resolution as a function of beam intensity 17

7. Measured  spectra ALLE= 1399MeVE= 1210MeV E= 1021MeVE= 831MeVE= 676MeV E= 261MeVE= 452MeVE= 72.1MeV E e =1508 MeV,  energy spread <= 1%, det. module No.1 ADC channel

8. Resolution vs. Energy E e = 855 MeV resolution ~ k. 1/sqrt(E)

9. Resolution vs. Energy E e = 1508 MeV resolution ~ k. 1/sqrt(E)

10. Resolution vs. Energy Module No.1 resolution ~ k. 1/sqrt(E) LE: E e = 855 MeV HE: E e = 1508 MeV cosmics: cosmics muons

11. Resolution vs. Energy Module No.2 resolution ~ k. 1/sqrt(E) LE: E e = 855 MeV HE: E e = 1508 MeV cosmics: cosmics muons

12. Resolution vs. Energy Module No.3 resolution ~ k. 1/sqrt(E) LE: E e = 855 MeV HE: E e = 1508 MeV cosmics: cosmics muons

13. Resolution vs. Energy Module No.4 LE: E e = 855 MeV HE: E e = 1508 MeV cosmics: cosmics muons resolution ~ k. 1/sqrt(E)

14. Resolution vs. Energy Module No.5 LE: E e = 855 MeV HE: E e = 1508 MeV cosmics: cosmics muons resolution ~ k. 1/sqrt(E)

15. Resolution vs. HV E e = 1508 MeV, module No.1 resolution ~ k. 1/sqrt(E)

16. Resolution vs. beam position reading only module No.1 reading modules No.1+2 E e = 855 MeV, module No.1 No.1 No.2 01234

17. Res. vs. amp. gain and beam intensity E e = 1508 MeV, module No.5 resolution ~ k. 1/sqrt(E) a) change of AMP gain – no influence b) decrease of  beam int. from 25kHz to 5kHz – improvement of resolution by 9% amplifier saturation