[Halld-level1] [New Logentry] Performance of the tagging detectors and PS/TPOL at high-rate

[somov at jlab.org]

Logentry Text:
--
We have performed high-rate performance tests of the tagging  
detectors TAGH/TAGM and the PS/TPOL

Run conditions:
---------------

Trigger: PS
Crates in the readout: TAGH1, TAGH2, TAGHM, PS1, PS2, STPSC1

Radiator:         JD 70-100 58 um
Electron current: up to 500 nA
Converter:        750 um

TAGH counters at low energies (CNT > 135, E > 8 GeV)
were switched off at 200 nA because of the high counter 
rate (R > 5 MHz/cnt), see Fig 1.

fadc250 readout windows for TAGH/TAGM were reduced to 
60/60 samples, respectively.

TPOL window size and readout threshold were set to 100 samples 
and 160 fadc counts (according to Nathan and Mike). TPOL is 
read out in the raw mode (mode 10).

The TDC window for tagging detectors was set to 500 ns
(window sizes will be optimized in the future).

fadc250 were readout in the compressed mode.

--------------

Some results of the lumi scan:

The data size from TPOL, starts saturating a 1 Gb Ethernet link at 
about 66 kHz trigger rate, see Fig 2.

We were able to readout tagger/PS crates (after excluding TPOL) 
at the rate of about 87 kHz with the L.T. of 95 %.

Note, the limiting factor is the data transmission rate; readout window 
sizes (and TAGM thresholds ) can be further optimized.

---

This is a plain text email for clients that cannot display HTML.  The full logentry can be found online at https://logbooks.jlab.org/entry/3448297
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