Scintillation counter installation on EBC

cryostatscintillators

gap scintillators

location ofMBTSscintillators

MBTS counterswill be pluggedinto fiber assemblies for 1/8 of cryostatscintillators

MBTS trigger The goal of the trigger is to be able to

define 1(2) filled bunches in conjunction with activity from the collision point

ATLAS Tilecal trigger cables will run from extended barrel up to rack where signals will be distributed through patch panels

understanding is that gap scintillators will be separated out through own connector

Q: what is meant by gap scintillators? Sometimes cryo scintillators are termed gap. Will find out.

MBTS counters will be plugged into PMT#1 (E#) which uses the muon trigger output; this may be bundled with other Tilecal trigger signals and will require intervention to separate out

NB

We will have to remove a cryostat scintillator for each MBTS counter in order to route the MBTS pigtail to the optical fiber assemblies

Can re-install only between runs

Higain counts Higain counts

eve

nts

eve

nts

50 mV trigger threshold4.6mV/pC at end of trigger cableX5 gain in coincidence board before descriminator12.5pC = 1024 counts (higain) => 50mV threshold = 178 counts on higain output

50mV threshold

50mV threshold

Tests performed at Chicago test-bench with counter

good separation between signaland noise offline; 30-40% efficiency per counter for mip attrigger level; trigger electronics notdesigned for this kind of signal

See however next slide

Muon trigger outputsOne of the PMT channels on each module has been

modified to have a higher gain (X30) for the L1 trigger output

The pigtails are long enough that inner and outer segments can be plugged into the modified channels on two adjacent Tilecal modules

This will boost signal and will boost S/N by an unknown amount (how much of noise is upstream of additional gain?) tests suggest 75% efficiency with 90% noise

rejectionNoise problems currently with finger supplies; would like

to check once situation is stable again with new trigger cables

Trigger signals What to do with trigger signals

once they leave patch panel? Is there a reason not to use the

Chicago stand-alone boards? I think Nick had an objection but

I can’t remember what it was Otherwise, we discussed using a

VME crate (either separate or sharing space with another system) and commercial logic boards that allow different combinations to be formed

A and C, A or C, etc If need be I can look for money

for buying components Output signal then goes to CTP

Issues

From Nick’s email to Ana can test trigger outputs of EBC drawers in ~1 month will get an idea of signal to noise using muon trigger

outputsSometime later (how much later?) can use

temporary trigger cables to send signals up to USA15

Better to wait until final EBC extended barrel trigger cables are installed?

How to test counters in place? Can we bring a source down to the cavern? How to measure radiation damage/aging? Keep track of average pulse heights from counters?