DIRC Prompt Reconstruction

Draft 0.3. J. Chauveau, L. DelBuono, L. Roos, M. Zito

DIRC detailed Monitoring

This document evolves from the comprehensive initial note by L. DelBuono, L. Roos, M. Zito prepared in the context of the DIRC OEP. Here we sort out the quantities which will be best monitored within the Prompt Reconstruction. This is the proposed scope for the so-called detailed monitoring for the DIRC (see D. N. Brown's HN for the vocabulary).
Recall the DIRC characteristic numbers: Nch=10 752 phototubes (PMT) are fed in groups of 8 into Nanalog=1 344 analog chips; two of those send signals to Ntdc=672 digital chips. The chips are mounted on Ndfb=168 Dirc Frontend Boards (DFB) which service 64 PMTs. Each of the 12 DIRC sector houses 1 frontend crate with a DIRC Crate Controller (DCC), so Ndcc=12. The PMTs are supplied high voltage in groups of 16, thus there are Nhv=672 high voltage lines. There ar=672 high voltage lines. There are Npm=896 PMTs in one sector. There is 1 bar box housing 12 quartz bars in front of each sector for a total of Nbar=144 bars. A typical event is expected to give Nhit=300 hits.

The aim is to provide the experimenter on shift with a picture of the DIRC response to physics events. We broadly categorize the quantities of interest into event related quantities, quantities which tell something about the optical transport of the photons and those more related to the detection (mainly electronics and phototubes) and data acquisition processes. Quantities which need to be followed over time are listed at the end.

The processed events will stem for various trigger types. We don't know yet their number Ntrig, but assume it is <=10. Various categories of events or event types will be useful to determine specific performances: Bhabhas (radiative or not), muon pairs, hadronic events, etc. We assume there will be 5 or less event types.

Available to the user, will be histograms, tables and scalars. Some will be available by default while others, only on demand when further details are needed.

In what follows a run is a block of contiguous data in time. It is anticipated these blocks will last about 30 minutes. Most plots are expected to be refrests are expected to be refreshed for each run/block. Exceptions are plots which look at small sections of the DIRC (plots made for each bar of fraction of a bar, plots made for each tube) and profile plots which follow measurements with time (typically one entry/run). The profile plots are assumed to contain 1000 bins (1 week including false starts).

Some caveats:

Remarks

Datastream Calibration

Alignement


Summary tables

1d plots

  /TD>

#plots

Plotted quantities

# bins

bin size

Purpose

priority

comments

1
#tdc_hits
1005overall efficiencytop
1
#unassoc'd_tdc_hits
1005overall noiset1005overall noisetop
12
#tdc_hits /sector
1001sector eff.medium
1
#assoc_tdc_hits vs sin(dip) [Bhabhas]
100.2N_pe_max vs diptop
1
#assoc_tdc_hits vs sin(dip) [mu pairs]
100.2N_pe_max vs diptop merge with above ?
1
#adc_hits
1005efficiencytopif available
1
#tdc_hits vs sector#
121sectors counting ratestop / on demandor medium, depends on fast monit. statistics
1
#tdc_hits vs DFB#
1681DFB counting ratessame
1
#tdc_hits vs HV line#
6721HV lines counting ratessame
1
#tdc_hits vs Digital Chip#
6721Digital Chip counting ratessame
1
#tdc_hits vs Analog Chip#
13441Analog Chip counting ratessame
1
t(L1)-t(TDC) (all hits)
15010 ns Coincidence windowtop
1
t(L1)-t(TDC) (assoc'd hits)
15010 ns top
12
t(L1)-t(TDC) (/sector. all hits)
15010 ns medium
<=10
t(L1)-t(TDC) (/trigger type, all hits)
15010 ns top
1
time-Tref (all hits)
405 ns Event durationtop
1
time-Tref (assoc'd hits)
405 ns top
1
BCO from DIRC
100 wishful thinking at this timetop
1
Tmeas-Texpected (assoc'd hits)
500.5 ns To calib. qualitytop
1
Cumulated ADC spectra (all hits)
100 PMT chargetopif available
12
Cumulated ADC spectra (/sector, all hits)
100 PMT chargelowsamelowsame
10 (dip angles)
Theta_c_meas - Theta_c_exp (Bhabhas)
50 top
10
Theta_c_meas - Theta_c_exp (Mu pairs)
50 topeventually summed with above
<=10
Phi_c (distrib. to be defined)
50 topsame
144
photon path length in quartz
50 topaverage across blocks?
144
nb of assoc'd photons vs theta_track
50 topthese or the previous series of plots or both
10752
tmeas-texp (each PMT)
500.5 ns Ultimate t_0 calibrationtopaverage across blocks?
10752
ADC-value (each PMT)
500.5 ns Ultimate charge calibrationtopif available
576
alignement residuals
50 top / on demand
55
profile histograms
10001000 top average across blocks

2d plots

 

#plots

Plotted quantities

# bins

bin size

Purpose

priority

comments

4
#tdc_hit map
>107521PMT counting ratetop (all, assoc'd, unassoc'd), medium (assoc's to xtals)zooms, see text
1
Theta_c vs P
>50 * 50 "Cerenk. thresh. curves"top
4
theta vs phi
20 * 200.05, 0.05 rad backgroundtop
576
theta vs phi
20 * 50.05, 0.2 rad bar scintillationmedium/on demand

Tables

See text above (for now).