1. Normalization p-Be 40 GeV (2001 data)
Running periods
Stability
- S4/S3,
Flux
- Cbeam/Beam
- CBeamDt/Beamdt
Proton fraction
- CerOr/S3
- CBCerOr/Cbeam
Burst Structure
Conclusion
NA57 meeting
June 2003
RL+OVB

2. Running Periods Three running periods: From beginning until 10.8,
1.4*10^7 good events
S3, S4, ST2, SPH11T, SPH12T, SPH21T, SPH22T, Beam, BeamDT, INT, INTDT, TelInt1T, TelInt2T, CU1, Cer1, Cer2, CerOR
From 10.8., 5.9*10^7 good events
Cbeam, CBeamDt
From 28.8., 2.7*10^7 good events
CBCer1, CBCer2, CBCAND, CBCOR

3. S4/S3 vs RUN

4. Normalization Yield =  weight / N N - number of interactions
N =(1- exp(L/)*Flux* Fract(proton)
L - target thickness
 - p Be interaction length
Beam DT
Flux =
CBeamDT
1 – CER1ORCER2/S3
Fract(prot)=
1 - CBCEROR/CBEAM
Two broblems:
Cbeam not available for allthe run
CBeamDT/Beamdt > 1

5. Cbeam/Beam vs RUN

6. Cbeam/Beam Spill length = 5.2 s, <S3>  10^7
Cbeam condition: no S3 in 45 ns before
and after Cbeam CB
P(CB) = P(Beam)*(exp(-45/520)^2
CB/Beam= 0.84
Electronic can not recognize S3 closer then
20-30 ns:
CB/Beam  exp(-35/520)^2= 0.87
 Correction for flux 4.7 %
exp(-35/520)= 0.953

7. BeamDT vs CBeamDT
Problem: CBeamDT/BeamDT > 1

8. Double Ratio Check (CBeamDT/Cbeam)/(BeamDT/Beam)
Stable and < 1 all the time !
Correct CbeamDT = Cbeam* (BeamDT/Beam)

9. Черенков (CerOr vs CBCerOr)
1 – CER1ORCER2/S3
Fract(prot)=
1 - CBCEROR/CBEAM
<CER1ORCER2/S3>  0.85
< CBCEROR/CBEAM>  0.7
Two effects:
beam misses S3 (dominant)
Run (logbook) S3.COR/S3  0.78
Run (end of burst) COR/S3  0.89
Cbeam protection – light from subsequent events
close in time can influence all of them

10. (CerOr/S3)/(CBCerOr/Cb)

11. S3.CerOr/S3

12. Cerenkovs – infinite time resolution
A) Ideal case:
CerOr = S3*0.7
CBCerOR =CB*0.7
CU1 = a*0.3*CB
B) 45ns gate - pion kills everything in 45 ns:
CerOr = S3*( *2*(1-exp(-45*0.7/520))=
= S3*( )
CU1 depends on period:
If Cbeam in trigger: CU1=a*CB*0.3
If Beam in trigger:
CU1= a*CB*0.3*(exp(-45*0.7/520))^2 =
= a*CB*0.3*0.886

13. Cerenkovs – 25 ns resolution
C) No 45 ns gate:
CerOr = S3*( *(1- exp(-25*0.7/520))=
= S3*( )
CBCerOR =CB*( )
CU1 = a*0.3*CB* exp(-25*0.7/520) =
= a*0.3*CB*0.967
D) 45 ns gate - pion kills everything in 45 ns:
CerOr = S3*( *2*(1-exp(-45*0.7/520))=
= S3*( ) (as B)
CBCerOR =CB*( ) (as C)
CU1 depends on period:
If Cbeam in trigger: CU1=a*CB*0.3*0.967 (as C)
If Beam in trigger:
CU1= a*Beam*0.3*exp(-45*0.7/520)^2 =
= a*CB*0.3* (as B)

14. Factors in Cerenkovs CBCerOR/CB = p(π)+0.01 CerOr/S3 = g*(p(π)+0.036)
g – geometry factor
CerOr/S3 = g*(CBCerOr/CB )
g = CerOr/S3/(CBCerOr/CB+0.026)
p(π) = CerOr/S3 * <(CBCerOr/CB+0.026)/(CerOr/S3)>-0.036
 CerOr/S3 * <(CBCerOr/CB)/(CerOr/S3)>
Last two factors cancel.

15. Correction factor I. Period: Beam in CU1 and CerOR
Flux = BeamDT*1.05*0.886
Proton Fraction = 1 – CerOr/S3*0.86
1.05=1/Prob(0 events after Beam in 25 ns)
0.886=factor for CU1 (see previous page)
0.86 = <(CBCerOR/CB)/(CerOR/S3)>
II. Period Cbeam in CU1 and CerOr
Flux = BeamDT*(Cbeam/Beam)*1.05
Proton Fraction = 1- CerOr/S3*0.86
III. Period: Cbeam in CU1 and CBeamCerOr
Flux = BeamDT*(Cbeam/Beam)*1.05
Proton Fraction =
= 1 – (CBeamCerOR/Cbeam )

16. Burst structure Run 17100 – event scalers info extracted
- S4/S3 versus event in burst
distribution of number of CbeamDT between
Subsequent CU1 plotted – should be
P( r ) = lambda/(1+lambda)^(r+1)
Lambda = cu1/cbeamDT

17. S4/S3 vs time in burst

18. Distribution of CBeamDT
Frequency
# of CBDT between two subsequent CU1
P( r ) = lambda/(1+lambda)^(r+1)
Lambda = cu1/cbeamDT
No free parameters !

19. Next Trigger inspection in NA57 Burst structure Distributions in run
Factors run by run

20. Introduction
End of Burst records extracted from raw data by Jozef Urban only for 2Track according to Ivan’s list
average values of scalers per run calculated
GOOD RUNS found checking scalers ratios and other sources
Target SPH2
S S SPH ST V0
50x x8