Comments: Absolute scintillator inefficiency as a function of initial (proton) momentum. It is clear that correction needs to be done for the proton momenta less than 1 GeV/c if one proceed with the cross-section measurements. At p=400 MeV/c this inefficiency could be more than 5 %.
Comments:
Nuclear interaction turned on
Absolute scintillator inefficiency as a function of S1 x-scint variable
for a number of proton momenta.
Events were initially generated in MCEEP for the D(e,e'p)n reaction using
100 MeV/c steps in proton momentum and then tracked in the GEANT FPP code.
Histograms show distribution of events which crossed S1 plane but haven't
hit S2 plane. Spikes at the histogram edges are due to the limited
number of events in these bins. At the same time real inefficiency
also gets larger near the geometrical boundaries of the scintillators
Comments:
Nuclear interaction turned off
It is clear that inefficiency almost entirely resulted from the N-N
collisions except for a tiny area near the edge of the S1 scintillator
where multiple scattering also contributed in case of the lowest
proton momenta.
E-arm cuts for each trigger type: | |
multiplicity | 1 (in 1 plane only) |
track number | 1 |
ADC gas Cherenkov | 0-6000 |
Scintillator TDC | 0-5000 |
S1: X-scint (m) | -1.05 0.8 |
S1: Y-scint (m) | -0.18 0.18 |
S2: X-scint (m) | -1.3 1.0 |
S2: Y-scint (m) | -0.32 0.32 |
S1:TDC left .OR. TDC right | true |
S2:TDC left .OR. TDC right | true |
T1,5 events require S1 TDC .AND. S2 TDC | true |
T2 events require S1 TDC .OR. S2 TDC | true |
H-arm cuts for each trigger type: | |
multiplicity | 1 (in 1 plane only) |
track number | 1 |
Scintillator TDC | 0-5000 |
S1: X-scint (m) | -1.1 0.85 |
S1: Y-scint (m) | -0.18 0.18 |
S2: X-scint (m) | -1.25 1.05 |
S2: Y-scint (m) | -0.32 0.32 |
FPP X (m) | -0.9 0.9 |
FPP Y (m) | -0.2 0.2 |
S1:TDC left .OR. TDC right | true |
S2:TDC left .OR. TDC right | true |
T3,5 events require S1 TDC .AND. S2 TDC | true |
T4 events require S1 TDC .OR. S2 TDC | true |
Comments: In H-arm FPP front chambers were used to
select good events. FPP X and Y are the x and y coordinates of the
track projected to the plane z=0, which is coincident with the first
plane of the vdc's
1) use awk to search and read database (e.g. runs_info.dat) for each run e.g. search for run number=[nrun] and read dead-time values corresponding to each trigger type do i=1,5 t=[i]+4 xdt[i]=$SHELL('cat runs_info.dat|awk ''/'//[nrun]://'/{print $'//[t]//'}'' ') dti[i]=1./(1.-[xdt[i]]) dt[i]=[dt[i]]+[dti[i]]*[nti[i]] enddo2) get averaged dead-time and prescaling values
where edt (cdt) are correction factors due to the electronic
(computer) deadtime
4) fit efficiency profile with a function (P6 in this case)
* Include this peace of code into the PAW++ KUMAC file used to fill * histograms from NTUPLE * Cut to limit scintillator acceptance within the physical boundaries ntu/cut $60 -1.<e_s1_x<0.75 ntu/cut $61 -1.1<e_s2_x<0.9 ntu/cut $62 -1.<h_s1_x<0.8 ntu/cut $63 -1.1<h_s2_x<0.9 * Read P6 polinomial coefficients from the file file=[main]efficiency/eff_[kinem].txt v/cr scint(7,4) R 28*0. v/read scint [file] ' ' do j=1,4 do i=1,7 k=$EVAL([i]-1) a[k][j]=$EVAL(scint([i],[j])) mess a[k][j] = [a[k][j]] enddo enddo * Calculate efficiency for each scintillator plane ntu/cut $64 $60*1/([a01]+[a11]*e_s1_x +[a21]*(e_s1_x*$60)**2 + ...) ntu/cut $65 $61*1/([a02]+[a12]*e_s2_x +[a22]*(e_s2_x*$61)**2 + ...) ntu/cut $66 $62*1/([a03]+[a13]*h_s1_x +[a23]*(h_s1_x*$62)**2 + ...) ntu/cut $67 $63*1/([a04]+[a14]*h_s2_x +[a24]*(h_s2_x*$63)**2 + ...) * Weight each event with corresponding correction factor * Cuts 52-55 are not related to this procedure ntu/cut $99 ($52.AND.$53.AND.$54.AND.$55)*[dtime_cor]*[vdc]*$64*$65*$66*$67 -------------------------------------------------------------------------------- INPUT FILE P6 coeff. for each of the four scint. planes 0.99662 0.75063E-04 -.72454E-02 0.16073E-02 0.46816E-01 -.68234E-02 -.91917E-01 0.99576 0.19941E-03 -.31770E-02 0.49745E-03 0.56260E-02 -.44618E-02 -.11486E-01 0.97318 0.18918E-01 -.45118E-01 -.13530 0.26501 0.20152 -.36370 0.98820 0.34333E-02 -.89079E-02 -.30557E-01 0.19490E-01 0.47556E-01 0.72603E-02
Comments: Number of T1,T5,T2, and T3,T5,T4 triggers (from left to
right) corrected for deadtime and scaling factors for the case of
=1.6
kinematics.
Comments: Efficiency profile, dashed red curve is result of the fit
Comments: Efficiency profile, dashed red curve is result of the fit
Comments: Efficiency profile, dashed red curve is result of the fit
Comments: Efficiency profile, dashed red curve is result of the fit. Efficiency fall sharply near the edge of the acceptance, significant inefficiency related to a single scintillator paddle in the S1 plane can be seen
Comments: Efficiency profile, dashed red curve is result of the fit. Efficiency fall sharply near the edge of the acceptance, significant inefficiency related to a single scintillator paddle in the S1 plane can be seen
Comments: Efficiency for both S1 and S2 are higher for these low proton momenta since at this energies protons deposit more energy and generate more light in the scintillator material. The fact that efficiency has such dependence indicate that we are dealing with ``real'' inefficiency due to insufficient light collection.
Comments:
Energy loss for ionization from the Bethe-Bloch formula. Arrows show
particle momenta corresponding to the E89028 experiment. It can be seen
that amount of light generated in scintillators by electrons and
protons was approximately the same for all kinematics except for
the case of low proton momentum setting of 700 MeV/c.