CENTRAL JET CHAMBER (CJC)

Who is the CJC Expert on Call ?

The CJC Home Page contains the following sections
(information marked by is only accesible for H1 users):

Information on CJC Status

Shift instructions

Operational Conditions

Technical data and tables

Field calculation

Some Pictures of the Detector

Publications

CJC Glossary

Information on CJC Status

• HV Status from H1DCM
• Tracking Hypernews

Shift instructions

• for shift crew
• for on call experts
• H1DCM HV Control manual

CJC Expert on call

There is a CJC expert on duty to assist the shift crew. Click here to get the name and phone numbers of this person.

Operational conditions

• 1994-2007

• Parameter and Performance

Technical data and tables

Contains some POSTSCRIPT files with detailed information.

• Dimensions / wire numbers (Table)
• Definition of wire positions (Article)
• Distribution of readout crates (Picture)

Still missing
Wire specs, Tensions and grav.sag, distribution of material ...

Field calculation

From the positions, diameters and voltages of the (anode and potential (see picture), cathode and field) wires the electrostatic field in the chamber can be calculated. With a parametrization of the drift velocity as a function of the field strength one can track (charges) outwards from the anodes to calculate isochrones (lines of equal drift times, dimensions in cm):

• CJC 1 isochrones for inner, middle, outer 3 layers
• CJC 2 isochrones for inner, middle, outer 3 layers
• CJC 1 "isochrones" for middle 3 layers tracking inwards

  Some field lines are ending not at the anode but at the potential wires resulting in a corresponding signal loss of about 30%.

Pictures of the Tracking Detectors

Backside views from shutdown 99/00: 1 2

Publications

• C. Niebuhr, Aging effects in the central jet chambers of the H1 experiment, Nucl. Inst. Meth. A 515 (2003) 43-49.
• C. Kleinwort, H1 alignment experience, First LHC alignment workshop, CERN report (CERN-2007-004, ISSN 0007-8328)

CJC Glossary

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