Analysis of TOF data

1. Yordan Karadzhov St.Kliment Ohridski University of Sofia Analysis of TOF data

2. Layout of the TOF system in Frascati test PMT left scintillator PMT right TOF bar electron beam finger 1 Bar 1 Bar 2 DAQ system Bar 3 finger 2

3. List of analyzed runs Run Energy TDC Splitter Discriminator • 124-133 350 MeV V1290 Active CAEN N417 • 141-149 300 MeV V1290 Active CAEN N417 & PLS 711 • 215-217 200 MeV V1290 & V775 Passive CAEN N417 & PLS 711 • 250-255 350 MeV V1290 & V775 Passive PLS 711 • 255-259 350 MeV V775 Passive CAEN N417 Because of the poor statistics we need to use a chain of runs taken in same conditions (experimental setup) and same beam energies.

4. ADC pulse height distribution (left PMT of bar 1) Example of the general event selection cut ADC spectrum in logarithmic scale Selection of single electron events Part of the same spectrum in linear scale

5. Intrinsic time resolution of the TOF bar Timebar2Timebar1 The quantity (Tleft – Tright )/2 has the same variation as (Tleft + Tright )/2but time jitter cancelled out, so the intrinsic time resolution of the bar could be evaluated more conveniently from its distribution.

6. Intrinsic time resolution of TOF bars Run 141 – 149 Distributions of (Tleft – Tright )/2 TDC V1290 Bicron BC420 - 4cm thick impact point at 10cm from Center Discr CAEN N417 σ = 63.91 ps Bicron BC420 - 4cm thick impact point at center Discr PLS 711 σ = 66.18 ps Bicron BC408 - 6cm thick impact point at center Discr PLS 711 σ = 109.7 ps

7. Intrinsic time resolution of TOF bars Run 124 – 133 Distributions of (Tleft – Tright )/2 TDC V1290 Discr CAEN N417 Bicron BC420 - 4cm thick impact point at 15 cm from center (5 cm from edge) σ = 72.73 ps Bicron BC420 - 4cm thick impact point at center σ = 64.91 ps Bicron BC408 - 6cm thick impact point at center σ = 107.2 ps

8. Intrinsic time resolution of TOF bars Run 215 – 217 Distributions of (Tleft – Tright )/2 TDC V1290 Bicron BC420 - 4cm thick impact at center Discr CAEN N417 σ = 44.22 ps Bicron BC420 - 4cm thick impact point at center Discr PLS 711 σ = 97.16 ps Bicron BC404 - 6cm thick impact point at center Discr PLS 711 σ = 49.21 ps

9. Intrinsic time resolution of TOF bars Run 215 – 217 Distributions of (Tleft – Tright )/2 TDC V775 Bicron BC420 - 4cm thick impact point at center Discr PLS 711 σ = 94.16 ps Bicron BC404 - 6cm thick impact point at center Discr PLS 711 σ = 41.61 ps

10. Intrinsic time resolution of TOF bars Run 250 and 251 Distributions of (Tleft – Tright )/2 TDC V1290 Bicron BC420 - 4cm thick impact at center Discr PLS 711 σ = 47.24 ps Bicron BC420 - 4cm thick impact point at center Discr PLS 711 σ = 115.4 ps Bicron BC404 - 6cm thick impact point at center Discr PLS 711 σ = 71.63 ps

11. Intrinsic time resolution of TOF bars Run 250 and 251 Distributions of (Tleft – Tright )/2 TDC V775 Bicron BC420 - 4cm thick impact at center Discr PLS 711 σ = 49.95 ps Bicron BC420 - 4cm thick impact point at center Discr PLS 711 σ = 101.4 ps Bicron BC404 - 6cm thick impact point at center Discr PLS 711 σ = 66.67 ps

12. Intrinsic time resolution of TOF bars Run 255 – 259 Distributions of (Tleft – Tright )/2 TDC V775 Discr Bicron BC420 - 4cm thick impact at center CAEN N417 σ = 90.76 ps Bicron BC420 - 4cm thick impact point at center CAEN N417 σ = 83.47 ps Bicron BC404 - 6cm thick impact point at center CAEN N417 σ = 105.4 ps

13. Run Energy TDC Splitter Discriminator 124-133 350 MeV V1290 Active CAEN N417 BC 420 – 72.73 ps V1290 Active CAEN N417 BC 420 – 64.91 ps V1290 Active CAEN N417 BC 408 – 107.2 ps 141-149 300 MeV V1290 Active CAEN N417 BC 420 – 63.91 ps V1290 Active PLS 711 BC 420 – 66.18 ps V1290 Active PLS 711 BC 408 – 109.7 ps 215-217 200 MeV V1290 Passive CAEN N417 BC 420 – 44.22 ps V1290 Passive PLS 711 BC 420 – 97.16 ps V1290 Passive PLS 711 BC 404 – 49.21 ps 215-217 200 MeV V775 Passive CAEN N417 BC 420 – V775 Passive PLS 711 BC 420 – 94.16 ps V775 Passive PLS 711 BC 404 – 41.61 ps 250-251 350 MeV V1290 Passive PLS 711 BC 420 – 47.24 ps V1290 Passive PLS 711 BC 420 – 115.4 ps V1290 Passive PLS 711 BC 404 – 71.63 ps 250-251 350 MeV V775 Passive PLS 711 BC 420 – 49.95 ps V775 Passive PLS 711 BC 420 – 101.4 ps V775 Passive PLS 711 BC 404 – 66.67 ps 255-259 350 MeV V775 Passive CAEN N417 BC 420 – 90.76 ps V775 Passive CAEN N417 BC 420 – 83.47 ps V775 Passive CAEN N417 BC 404 – 105.4 ps

14. Time of Flight and Time-walk effect • Because leading edge discriminator has been used for the time measurements, the time-walk effect should occur. • Time-walk should effect measured TOF especially in cases when we have different total charge collected in the bars. • This effect can be suppressed by constrain on difference in ADC pulse heights (signals with same pulse heights will give approximately same time-walk).

15. Time of Flight and Time-walk effectRun 124-133 no constrain σ = 134.7 ps σ = 123.5 ps σ = 91.27 ps

16. Time Of Flight and Time-walk effect Run 124-133

17. Conclusions • Intrinsic resolution of the bars made of BC404 or BC420 is satisfactory. BC 408 is significantly worse. • Passive splitter gives better performance than active. • TDC V775 gives a little bit better results than V1290. • We need more detailed investigation of the relation between intrinsic time resolution and position of the impact point. • The effect of time-walk is significant and should be corrected for.