CBM -Russia meeting, ITEP, 5 November 2004

 

DEVELOPMENT OF LOW RESISTIVE GLASS FOR HIGH RATE RPC

 

F.Guber, INR, Moscow 

C B M

Schematic view of the TOF

- Total area about 130 sq. m.-Standard material properties sufficient for ~ 70% of solid angle- Different concepts for different polar angles

Hit rate and densities for Au+Au collisions at 25 GeV/n (rates – 10 MHz min. bias collisions, hit density for central collisions)

Window glass

Properties of different kind of materials

  Window glass Semiconductive glass

Bakelite

  (·cm) 

 1012 - 1013

 108 - 1011

 109 – 1012

Mass production 

yes No(no market)

yes

Surface quality 

good good no

Stability with freons 

Some problems bad good

Type of conductivity 

ion electron ion

Polarization 

yes no yes

Semiconductive glasses – phosphate glasses, - silicate glasses, - vanadium glasses

Yu.Pestov, NIM A494(2002)447

Progress in the low resistive glass development

 

- development of glass samples with resistivity near 109Ωcm (special semiconductor “black” (phosphate) glasses ) and production of the glass samples 30 x30 x 5 mm3 ; - production of few plates 100 x 100 x 2 mm - construct prototype RPC detector

- tests on the beam test of RPC prototype in ITEP (Results have been presented by A.Smirnitsky– previous report)

The work has been done in the close cooperation between INR, ITEP and IHEP

 

Low Resistive Glass for first RPC Prototype

- Phosphate glass- electron conductivity- low resistive

Problem – difficult formass production

U=1000v

First sample of phosphate low resistive glass

Plates produced by cut and polishing from glass block,

size 100 x 100 x 2 mm

Silicate glasses- few samples 30 x 30 x 5 mm are available- low resistivity- more technological for industrial production

Problems to be solved: - development of the technology of glass block production (regimes of heating and cooling, crystallization problems etc.) - very aggressive melt - needs special crucible from platinum - development of large sizes glass sheets production method

U = 1 kV

The nearest plans

- to produce low resistive silicate plates 100 x 100 x 2 mm, - to construct new RPC prototype from these plates, - test the RPC prototype on the ITEP test beam, December 2004 ? (INR-ITEP-IHEP) - production of silicate glasses by semi industrial way (by extraction from glass melt) the plate with size about 1000 x 200 x (1-2) mm and with the thickness even less than 0.5 mm - to write the contribution for the Technical Proposal

Long-range plans of INR team

-Development of low resistive glasses for production of high rate RPCs,- New type of detectors for TOF (APDs -??)