rpc dae

Results from development ofGlass RPCs for INO detector: 

Results from development of Glass RPCs for INO detector B.Satyanarayana (For INO Collaboration) TIFR, Mumbai

Plan of the presentation: 

Plan of the presentation Introduction Principle of operation of a glass RPC Overview of the field Our prototype designs and fabrication RPC gas mixtures and gas system Cosmic ray muon telescope Data acquisition system Preliminary results RPC aging problem Future work plan

Introduction: 

Introduction Neutrinos are one of the fundamental particles of matter. Electrically neutral and were initially thought to be mass less. Three types or flavors (ne,nm,nt) of neutrinos known. Recent evidence indicates that neutrinos have mass and also experience mixing among these flavors. Neutrino oscillations can explain the discrepancy between theory and observations about its flux; can be used to estimate its mass. Pioneering experiments at the KGF underground laboratories. Formation of Indian Neutrino Observatory (INO) collaboration. Feasibility studies for setting up of a neutrino experiment in India is in progress.

Proposed INO detector: 

Proposed INO detector Magnetised iron calorimeter Iron RPC 140 layers RPC dimension: 3m X 2m No of chambers: 11K No of channels: 220K No of TDC channels: 3K 35KTons

Principle of operation of a RPC: 

Principle of operation of a RPC V-I model Each discharge locally deadens the RPC. The recovery time is approximately

Our prototype designs: Single gap: 

Our prototype designs: Single gap Gas inlet HV terminals Graphite coat Gas outlet Spacer Two versions

Our prototype designs: Double gap: 

Our prototype designs: Double gap Double gap RPC for better detection efficiencies

Jigs for RPC fabrication: 

Jigs for RPC fabrication A glued RPC Resistivity measurement jig A finished small area RPC RPC fabrication jig Glue and dispensers Glass handlers

Gas mixing and flow control unit : 

Gas mixing and flow control unit Gas mixing unit Flow monitor

Schematic of Cosmic ray muon trigger: 

Schematic of Cosmic ray muon trigger

Cosmic ray muon telescope setup: 

Cosmic ray muon telescope setup Mounting structure for flexible and precise telescope alignment Paddle alignment detail

Schematic of data acquisition system: 

Schematic of data acquisition system

Data acquisition system electronics: 

Data acquisition system electronics NIM CAMAC

V-I characteristics: 

V-I characteristics Small RPC Large RPC

Typical RPC pulse profile: 

Typical RPC pulse profile RPC pulse Muon trigger

Noise rate and efficiencies: 

Noise rate and efficiencies

Charge performance: 

Charge performance

Timing performance: 

Timing performance

Charge-time linearity: 

Charge-time linearity

RPC aging problem: 

RPC aging problem Drop in efficiency, increase in noise rate and chamber current seen after a few weeks of continuous operation Reports in the literature (Monolith, Belle etc) Moister contamination in Freon gas, the culprit? Use of SF6 instead of Freon preferred

Controlled humidity test: 

Controlled humidity test Carlo Gustavino et al, LNGS

AFM images of damaged electrodes: 

AFM images of damaged electrodes 2 scans 10 scans Damaged electrodes Damaged electrodes Raw glass Raw glass 500nm structures of 100nm thick seen in the images

SEM image of damaged electrode: 

SEM image of damaged electrode 6 scan 2 scan Damaged electrode Fluorine: 38% Raw glass Fluorine: 4%

Future work plan: 

Future work plan Systematic study of RPC stability problem Fabrication of more large area RPCs and studies Detailed studies on timing, spatial resolution, cross-talk Optimization of detector gas composition INO prototype detector; needs about 16 large area RPCs Performance studies of prototype detector; comparison of results with those from simulation studies RPC Parameter inputs for electronics and data acquisition system design Full pledged RPC device simulations

Backup slides: 

Backup slides

RPCs of modern designs: 

RPCs of modern designs Multi gap Hybrid RPC Micro RPC Applications in HEP research Cosmic ray experiments: EAS-Top, Cover-Plastex, Argo, Auger Accelerator based experiments: Belle, Babar, Star, Harp Future experiments: Alice, ATLAS, CMS, LHCb Medical applications etc

Telescope stability monitoring: 

Telescope stability monitoring

Preliminary cross-talk measurements: 

Preliminary cross-talk measurements

Recovery of a damaged RPC: 

Recovery of a damaged RPC Purging with pure Argon at high flow rate. Bubbling pure Argon through pure ethyl alcohol. Bubbling pure Argon through 3% Ammonia solution for 24 hours with high voltage off. Recovers efficiency and brings down noise rate.