Thomas Jefferson National Accelerator Facility Page 1 Hall B Drift Chambers Review, March 2007...

Thomas Jefferson National Accelerator Facility

Hall B Drift Chambers Review, March 2007

George JacobsGeorge JacobsJefferson LabJefferson Lab

Hall B 12 GeV Upgrade Drift Chamber Review Jefferson Lab

March 6- 8, 2007

CLAS12 Drift Chambers Utilities and Support Systems



Drift Chamber Utilities and Support Systems

The Drift Chamber Gas (DCGAS), Drift Chamber Low Voltage (DCLV), and Drift Chamber High Voltage

(DCHV) systems are already in place with mature control, monitoring, and alarm subsystems.

These systems will be USED in CLAS12 with minor modifications and upgrades.



CLAS DC Gas System Overview

System consists of 2 separate mixing and storage systems System originally designed to mix 2 different gas mixtures

Original design for Argon-Ethane and Helium-Ethane Current mix is 10% CO

2, 90% Argon in both

Twin systems also provides redundancy

System consists of 3 separate supply and pressure control systems System was originally designed to recirculate gas Current system exhausts to atmosphere

Each region is separately monitored for contaminants

System has active and passive safety controls Active controls isolate the detectors in case of high or low pressure

Passive high capacity pressure relief bubblers attached to detector exhausts

System designed to Fail Safe on loss of power



CLAS DC Gas – Mixing and Storage



MKS MFC based mixing system

Panametrics TCU monitor the mix

Calibration gases are used to match the mix

Panametric moisture image monitors H2O

Teledyne trace O2 transmitters monitor O

2

MKS based pressure controls for DC

Magnahelic based active safety system

Bubbler based passive safety reliefs

Fail Safe design on loss of power

CLAS DC Gas Controls



Hall B Gas Shed



CLAS DC Gas Flow Paths



CLAS DC Gas Controls



CLAS DC Gas Hall Hardware



Current System Capacities

R1 - 15 minutes at maximum flow rate (48 slm)R1 - 30 minutes standard flow (24 slm)

R2 - 1.5 hours at maximum flow rate (90 slm)R2 – 2.25 hours at standard flow (60 slm)

R3 – 3 hours at maximum flow rate (120 slm)R3 – 5 hours at standard flow (72 slm)

CLAS DC Gas Volume Exchange Rate



EPICSDCGASGUI

CLAS DC Gas EPICS Interface



CLAS12 DC Gas Upgrade

Complete System will be reused as is with minor plumbing mods required in the Hall

1) Relocate supply and exhaust manifolds in Hall

2) Run new piping to the manifolds from the hall gas panel

3) Run new piping from manifolds to the individual detectors in the Hall

4) Relocate the over and under pressure protection bubbler units

New System Operating Parameters

- CLAS12 gas volumes will be less than the current detectors for R2 and R3

- CLAS12 volume exchange rate for R2 and R3 will increase

- CLAS12 volume exchange rate will decrease for R1

- CLAS12 R1 volume exchange time will increase to 1.25 hours

- Gas flow capacity can be increased by adding pumps and/or adding parallel control valves

Disconnect the gas lines from the old detectors and connect them to the new ones



CLAS DC Low Voltage

DCLV supplies power to on chamber pre-amps HP6651 DC power supply rated at 8vdc 50amps LabView GUI based monitor and alarm system Very dependable Power supplies with only 1 crate failure

in the 10+ years of operation



CLAS DC Low Voltage Monitoring System



The HP power supplies and GPIB monitoring equipment will be reused as is.

No software changes are required for the LabView based monitor and alarm systems. Decrease channels per sector to 1344 reducing current to ~20 amps per sector

Increase Segmentation to 1 fuse per 32 channels or 42 fuses per sector

Reduce current per segment or fuse to <0.5 amps

R3 DCLV is ready but R1 and R2 DCLV will require new distribution fuse boxes

CLAS 12 conversion will require new DCLV cable runs from the fuse boxs to the patch panels on each sector.

CLAS12 DC Low Voltage Upgrade



DCHV provides HV to the DC

CLAS DCHV System consists of 3 CAEN System 527 HV Mainframes.

System is controlled via a CAEN Network VME card using the DCHV GUI

There are 10 HV modules per crate, 24 Channels per module, 40 micro-amps per channel

16 +HV and 16 -HV channels are available for each individual sector

DCHV GUI allows for easy operations for ramping up and down the DCHV

DCHV GUI permits operation of single sector, region, or channels

DCHV GUI permits adjusting voltages, trip set points, ramp rates, etc

CLAS DCHV – Drift Chamber High Voltage



CLAS DCHV Control GUI



CLAS DCHV Groups



R2 and R3 HV distribution panels can be used as is with new labels R1 requires new HV distribution panels to segment the HV channels Requires CAEN crate reprogramming for new group configurations

CLAS12 DCHV – High Voltage Upgrade



CLAS12 Region I HV Patch Panel



CLAS R3 R

epair



Summary

The required utilities, DCGAS, DCLV, and DCHV are already in place and require minimal modifications for the CLAS12 upgrade.

Systems have been refined and optimized over a decade of operation.

Controls and alarm systems are mature and have already been debugged.

The technical staff has many years of experience with these systems.

Trained system experts rotate for 24-7 on call support for these systems.

Thomas Jefferson National Accelerator Facility Page 1 Hall B Drift Chambers Review, March 2007...

Documents

Transcript of Thomas Jefferson National Accelerator Facility Page 1 Hall B Drift Chambers Review, March 2007...