TITLE>MuTr Mechanics Fault Chart

Muon Tracker Mechanics Fault Chart

CSC Gas System

Fault	System Effect	Possible Consequence	Monitors	Response
Chamber Leak	Mass flow difference between input and output Increase in O₂ and H₂O levels in gas Change in isobutane/CF₄ ratio in gas Change in difference pressure across chamber	Chamber currents increase Chamber HV trips Flammable gas in magnet volume Fire Loss of chamber efficiency	Flammable gas monitors Gas composition monitors Mass flow meters	Turn off pump Close chamber valves or Nitrogen purge Turn off HV Initiate operator alarm
Over pressure	Differential pressure to atmosphere at chamber	Blow window or distort panel	Differential pressure monitor to atmosphere	Passive bubbler pressure relief Close backflow valve at pump Inform operator
Under pressure	Differential pressure to atmosphere at chamber	Implode window or distort panel	Differential pressure monitor to atmosphere	Passive bubbler pressure relief Open backflow valve at pump Inform operator
Gas purity	Increase in O₂ and H₂O levels in gas Change in isobutane/CF₄ ratio in gas	Chamber currents increase Chamber HV trips Loss in chamber efficiency	O₂ and H₂O ppm monitors Isobutane/CF₄ ratio monitor	Inform operator
Monitoring equipment power failure (Gas hut)	Overall gas flow instantly reads zero All pressures in gas hut read zero Gas purity monitors read zero	Chamber currents increase Chamber HV trips	ONCS power monitor shows trip	Shut off pump Turn off HV Initiate operator alarm
Monitoring equipment power failure (Magnet)	Chamber input and output reads zero All pressures at manifolds read zero	Chamber currents increase Chamber HV trips	ONCS power monitor shows trip	Shut off pump Turn off HV Initiate operator alarm
Solenoid valves power failure	none	Loss of control	ONCS power monitor shows trip	Alarm operator
Pump power failure	Overall gas flow goes to zero Differential pressure across pump goes to zero	Chamber currents increase Chamber HV trips	Differential pressure monitor Absolute pressure monitors	Turn off HV Initiate operator alarm
Fire	Heat and smoke	Loss of chamber and electronics	Fire alarm Smoke detector	Shut off pump Close chamber valves or nitrogen purge Turn off HV Initiate operator alarm

Detector Systems

Fault	System Effect	Possible Consequence	Monitors	Response
High leakage current	HV channel senses increase in current	Broken wire spark	HV module	HV channel trips off Initiate operator alarm
Broken Wires	HV short	Damage to cathode foil Spark	HV module	HV channel trips off Initiate operator alarm

Fault

System Effect

Possible Consequence

Monitors

Response

High leakage current

HV channel senses increase in current

Broken wire

spark

HV module

HV channel trips off

Initiate operator alarm

Broken Wires

HV short

Damage to cathode foil

Spark

HV module

HV channel trips off

Initiate operator alarm

High Voltage Systems

Fault	System Effect	Possible Consequence	Monitors	Response
High current draw on individual channel	HV channel senses increase in current	Broken wire Spark	HV module	HV channel trips off Initiate operator alarm
Requested and readback voltage error	Incorrect voltage Inoperative chamber	Loss of chamber efficiency	ONCS	HV channel trips off Initiate operator alarm
DC power failure in crate	Bad readback or current or voltage value	Loss of chamber voltage Damage to wire	ONCS	Turn off HV and crate Initiate operator alarm
AC power failure	All channels voltages and currents go to zero	Loss of Efficiency	ONCS	Initiate operator alarm HV is off

Edited by: Dave Lee, Los Alamos National Laboratory, Los Alamos, NM
Date: Fri, Jul 10, 1998 17:38