Ren-Yuan Zhu. 1 st Report on Twenty Mu2e BaF 2 Crystals from SIC. California Institute of Technology. June 25, 2014

Transcription

1 1 st Report on Twenty Mu2e BaF 2 Crystals from SIC Ren-Yuan Zhu California Institute of Technology June 25, 2014 Mu2e Calorimeter Collaboration Meeting 1

2 Crystal Samples and Experiment SIC-1 SIC-2 SIC-3 SIC-4 SIC-5 SIC-6 SIC-7 SIC-8 SIC-9 SIC-10 SIC-11 SIC-12 SIC-13 SIC-14 SIC-15 SIC-16 SIC-17 SIC-18 SIC-19 SIC-20 Sample ID Received Date Dimension (mm 3 ) Total # Polish SIC-1,20 4/25/ Six surfaces Properties measured: longitudinal transmittance, FWHM resolution for 511 kev ɣ-rays, decay kinetics and light response uniformity. 2

3 Longitudinal Transmittance of No 1-10 Good transmittance approaching theoretical limit 3

4 Longitudinal Transmittance of No Good transmittance approaching theoretical limit 4

5 Summary of LT Consistency of 4.1% and 1.6% respectively at 220 nm and 300 nm June 25, 2014 Caltech HEP Crystal Laboratory 5

6 Summary of EWLT Consistency of 3.6% and 1.4% respectively for fast and slow component June 25, 2014 Caltech HEP Crystal Laboratory 6

7 Setup for PHS, LO and Decay Measurement Crystals are wrapped with two layers of Tyvek paper. Coincidence trigger provided by a 22 Na source. June 25, 2014 Caltech HEP Crystal Laboratory 7

8 Example of Pulse Height Spectra 2.5 μs gate sees 2.3 times better resolution than 50 ns gate Average ER = 41.7% with 50 ns gate Average ER = 17.8% with 2.5 μs gate 8

9 Summary of ER Consistency of 5.9% and 5.6% respectively for 50 ns and 2.5 μs gate June 25, 2014 Caltech HEP Crystal Laboratory 9

10 Decay Kinetics of No.1-10 Consistent fast and slow scintillation component observed June 25, 2014 Caltech HEP Crystal Laboratory 10

11 Decay Kinetics of No Consistent fast and slow scintillation component observed June 25, 2014 Caltech HEP Crystal Laboratory 11

12 Summary of Fast and Slow Light Output 7.5% consistency observed SIC-9 June 25, 2014 Caltech HEP Crystal Laboratory 12

13 Summary of Decay Time Consistency of 1.3% observed for decay time of the slow component June 25, 2014 Caltech HEP Crystal Laboratory 13

14 Effect of Crystal Wrapping The highest LO observed for crystals wrapped with 8 layer Teflon films Additional Al foil does not increase LO June 25, 2014 Caltech HEP Crystal Laboratory 14

15 Summary Good optical quality with consistency of 4% and 3% at 220 nm and 300 nm respectively is observed. By using a PMT with a bi-alkali cathode and a quartz window and coincidence trigger from a 22 Na source, crystals wrapped with two layers Tyvek paper show: FWHM energy resolution of 45/19% for 50 ns/2.5 μs integration. Light output of 105/575 p.e./mev for the fast/slow component. Overall consistency of light output of 7.5%. Initial trying with existing wrapping material shows the following order in light output: Eight layer of PTFE Teflon film (8 x 25 μm), Aluminized Mylar, two layers of Tyvek paper (2 x 150 μm 1056D) and ESR. Additional Al foil on Teflon and Tyvek does not help. Test with solid Teflon reflector (6.5 mm thick) is under way. Investigation on light response uniformity is under way. 15

16 Average ER = 43.3% Average ER = 17.8% 16

17 Average ER = 46.1% Average ER = 19.2% 17

18 Average ER = 48.2% Average ER = 19.1% 18

19 Average ER = 44.8% Average ER = 18.3% 19

20 Average ER = 46.5% Average ER = 18.8% 20

21 Average ER = 47.2% Average ER = 19.4% 21

22 Average ER = 43.6% Average ER = 18.5% 22

23 Average ER = 51.3% Average ER = 22.4% 23

24 Average ER = 45.4% Average ER = 18.6% 24

25 Average ER = 45.9% Average ER = 19.0% 25

26 Average ER = 45.2% Average ER = 18.8% 26

27 Average ER = 40.4% Average ER = 17.2% 27

28 Average ER = 42.2% Average ER = 18.3% 28

29 Average ER = 45.6% Average ER = 19.2% 29

30 Average ER = 42.0% Average ER = 17.9% 30

31 Average ER = 41.6% Average ER = 18.1% 31

32 Average ER = 42.6% Average ER = 18.1% 32

33 Average ER = 43.6% Average ER = 18.0% 33

34 Average ER = 41.4% Average ER = 17.8% 34