Group MeetingGroup Meeting2004/07/082004/07/08

Jia-Ye ChenJia-Ye Chen

ContentsContents

1.1. SDLT 320 Autoloader (MTX)SDLT 320 Autoloader (MTX)

2.2. TPC (part1) TPC (part1)

3.3. Improvement of the Wire Gain Near the Improvement of the Wire Gain Near the Frame of a TPCFrame of a TPC

SDLT 320 Autoloader SDLT 320 Autoloader (MTX)(MTX)

SDLT had installed on the “hepfs” fileserver coSDLT had installed on the “hepfs” fileserver completely.mpletely.

To install the remote control software, MTX, anTo install the remote control software, MTX, and it could work now. Only “SuperUser” could exd it could work now. Only “SuperUser” could execute the MTX program.ecute the MTX program.

Waiting for reboot the host-computer (hepfs fileWaiting for reboot the host-computer (hepfs fileserver) to initialize the Sequential-Access modserver) to initialize the Sequential-Access mode.e.

A simple “MTX User Guides” was finished.A simple “MTX User Guides” was finished.

Time Projection ChamberTime Projection Chamber

Basic elements of a TPCBasic elements of a TPC

Schematics of the drift and detection Schematics of the drift and detection process of charges on the wires of the process of charges on the wires of the TPC end-plateTPC end-plate

Schematic arrangement Schematic arrangement of a wire chamberof a wire chamber

Electric field lines in a Electric field lines in a cell of a MWPC for a TPCcell of a MWPC for a TPC

Electric field lines with the gate in Electric field lines with the gate in “open state” and in “closed state”“open state” and in “closed state”

Different modes for gating Different modes for gating the TPCthe TPC

Improvement of the Wire Improvement of the Wire Gain Near the Frame of a Gain Near the Frame of a Time Projection ChamberTime Projection Chamber

1. In wire chamber the gain usually drops to zero near the frame.

2. The gain loss close to the frames which hold sense and field wires is caused by modification of the E field: due to the dielectric constant ε of the glassfiber epoxy frame and the glue, the density of the electric field lines is reduced close to the sense wires edges.

3. The aim of the test was to find a voltage combination on the guards that could recover the gain keeping safe chamber operation.

Section of the FrameSection of the Frame

Results of the test with Results of the test with both guard ringsboth guard rings