RPC Barrel EDR Chapter 3 3. Production and control of Bakelite 3.1 Definition and standards Standard bakelite electrodes are composed by a bulk made of phenolic resin a surface made of melaminic/phenolic resin In the following: Melaminic = bulk phenolic and surface melaminic Phenolic = bulk and surface phenolic Standard bakelite electrodes are composed by a bulk made of phenolic resin a surface made of melaminic/phenolic resin In the following: Melaminic = bulk phenolic and surface melaminic Phenolic = bulk and surface phenolic BULK SURFACE

RPC Barrel EDR Chapter 3 3. Production and control of Bakelite 3.2 Quality control data flow Bulk resistivity  Determines the time constant of an elementary RPC cell,  =  0 (  r + 2 )  Average roughness R a It is related to the quality of the surface. A small R a reduces spontaneous discharges which might affect the RPC rate capability Dielectric constant  r It is related to  and to the average fast charge q e of a single avalanche Bulk resistivity  Determines the time constant of an elementary RPC cell,  =  0 (  r + 2 )  Average roughness R a It is related to the quality of the surface. A small R a reduces spontaneous discharges which might affect the RPC rate capability Dielectric constant  r It is related to  and to the average fast charge q e of a single avalanche Protocol Production Measurement Storage Data acquisition Out of range Decide limits for accepting a given bakelite sheet on the basis of measurements Decide limits for accepting a given bakelite sheet on the basis of measurements

RPC Barrel EDR Chapter 3 3. Production and control of Bakelite 3.3 Production requirements Resistivity range : 2/3 of production in the range    =  cm 100% of production in the range    =  cm Resistivity range : 2/3 of production in the range    =  cm 100% of production in the range    =  cm Average Roughness range : R a = < 0.2  m Average Roughness range : R a = < 0.2  m Size (thickness = 2 mm) : 1.3 m x 2.8 m“small” slabs 1.3 m x 3.2 m “large” slabs Needs: 3000 (+150) “small” slabs (11466 m 2 ) 500 (+ 25) “large” slabs (2184 m 2 ) Total 3675 Slabs (13650 m 2 ) Size (thickness = 2 mm) : 1.3 m x 2.8 m“small” slabs 1.3 m x 3.2 m “large” slabs Needs: 3000 (+150) “small” slabs (11466 m 2 ) 500 (+ 25) “large” slabs (2184 m 2 ) Total 3675 Slabs (13650 m 2 )

RPC Barrel EDR Chapter 3 3. Production and control of Bakelite 3.4 Resistivity control Factory Main Parameters : How much the resin spreads out on the paper foil Percentage of resin in the paper Relate the factory parameters to the bulk resistivity Type of Paper Flow Resin Volatile Heating Temperature Pressing Temperature Resin Reactivity Percentage of additives Volatile GOES Up Down Resin  

RPC Barrel EDR Chapter 3 A measured  value has to be multiplied for a multiplicative factor (  20 /  to obtain   ( i.e.  at T=20 C ) A measured  value has to be multiplied for a multiplicative factor (  20 /  to obtain   ( i.e.  at T=20 C ) T ( 0 C) 3. Production and control of Bakelite Temperature dependence The resistivity depends on the temperature T  20 /  = exp(  (20-T) ) The resistivity depends on the temperature T  20 /  = exp(  (20-T) ) To define a common production protocol we usually quote a resistivity value at T = 20 0 C using as normalisation the following experimental curve.  20 / 

RPC Barrel EDR Chapter 3 Here temp starts to decrease while Then also  starts to increase 3. Production and control of Bakelite Resistivity and Temperature Note also the ``inertia” of the bakelite in following the temperature change  (x )  cm T (C)  is still constant

RPC Barrel EDR Chapter 3 3. Production and control of Bakelite 3.6 Resisitivity range Bulk resistivity measurements - melaminic: production is able to reproduce the useful resistivity range Slabs   (x )  cm

RPC Barrel EDR Chapter 3 3. Production and control of Bakelite Roughness range Roughness Quality Qualitative view of the surface improved bakelite. Pixel matrix greyscale of a micro-picture of the surface Pixel Greyscale Value X (Pixels) Y (Pixels) X 600 magnification

RPC Barrel EDR Chapter 3 3. Production and control of Bakelite Roughness range R a (  m) Vertical deviation of the surface from its average profile RaRa Measurements points on the surface

RPC Barrel EDR Chapter 3 3. Production and control of Bakelite Resistivity measurement Needs good electrical contact between electrodes and bakelite Needs good electrical contact between electrodes and bakelite We tried several options for the contact - among others: sponge with water antistatic foam (with and without water) conductive gel conductive rubber We tried several options for the contact - among others: sponge with water antistatic foam (with and without water) conductive gel conductive rubber Brass Electrodes Upper 5 cm Lower 10 cm for guard ring option

RPC Barrel EDR Chapter 3 3. Production and control of Bakelite Resistivity measurement Constant pressure (3 atm) on the electrodes How to measure  ~  cm R = 10 ,100 k    = k V 0 /(V/R) k = geometrical factor V 0 = 500 Volts V0V0 V R

RPC Barrel EDR Chapter 3 3. Production and control of Bakelite Resistivity measurement Upper electrode Lower electrode

RPC Barrel EDR Chapter 3 3. Production and control of Bakelite Systematic A piston with conductive rubber is continuously measuring the resistivity of a bakelite sample; after a predetermined set of measurements the piston moves up for a fixed time and back down on the sample for the next cycle of measures. Number of cycles, number of measurements within a cycle, time between cycles and time between measurements are supplied by the user. Automatic reading of Temperature and Humidity is provided. A piston with conductive rubber is continuously measuring the resistivity of a bakelite sample; after a predetermined set of measurements the piston moves up for a fixed time and back down on the sample for the next cycle of measures. Number of cycles, number of measurements within a cycle, time between cycles and time between measurements are supplied by the user. Automatic reading of Temperature and Humidity is provided.

RPC Barrel EDR Chapter 3 3. Production and control of Bakelite Systematic 400 cycles of measurements, 10 meas./cycle, 10 sec after each measurements (~13 hours). The resistivity (at T= 20 ° C) of a melaminic sample as a function of time is plotted (left hand scale- purple). The recorded value of the Humidity is also shown (right hand scale - blue) 13 hours

RPC Barrel EDR Chapter 3 3. Production and control of Bakelite Systematic Frequency distribution of  20 /  = 5,2 % We can measure  at a level of 5 %

RPC Barrel EDR Chapter 3 3. Production and control of Bakelite Station for resistivity measurement Lifting belt- conveyors bed Fixed frame Transverse beams supporting the upper electrodes system Pistons BAKELITE

RPC Barrel EDR Chapter 3 3. Production and control of Bakelite Station for resistivity measurement Upper position of the belt conveyors bed for bakelite loading and unloading Pistons integral to the upper beam of the fixed frame Fixed frame Mobile frame integral to the belt conveyors bed Position of the lower electrodes integral to the lower beam of the fixed frame Rectified cylinder Pneumatic piston for belt conveyors lifting Adjustable feet Conveyors belts Lateral guide Lower position of the belt conveyors bed for measurements

RPC Barrel EDR Chapter 3 3. Production and control of Bakelite Station for resistivity measurement position A position B Side view lengths in mm

RPC Barrel EDR Chapter 3 3. Production and control of Bakelite Station for resistivity measurement position A position B Front view (lengths in mm) Bakelite

RPC Barrel EDR Chapter 3 3. Production and control of Bakelite Station for resistivity measurement Top view (lengths in mm)

RPC Barrel EDR Chapter 3 3. Production and control of Bakelite Station for resistivity measurement Setup for DAQ and measurements bench-tests

RPC Barrel EDR Chapter 3 3. Production and control of Bakelite Station for resistivity measurement RS-232 Network Module 8 Ch, SPST Relays Module 8 Ch, 12 Bit Analog Input Modules 8 ch Universal Discrete Input Module Electronics: modular distributed I/O architecture FIELDPOINT (Nat. Instr.) with analog and discrete I/O modules, terminal bases and network communication module (RS232) DAQ: Labview 5.0x

RPC Barrel EDR Chapter 3 3. Production and control of Bakelite Station for resistivity measurement Pre-production Resistivity measurements at the factory Manual Measurements

RPC Barrel EDR Chapter 3 3. Production and control of Bakelite Station for resistivity measurement Pre-production Resistivity measurements at the factory Manual Prototype

RPC Barrel EDR Chapter 3 3. Production and control of Bakelite Quality control time schedule production Slabs at rest for a week measurements loadingunloading stacking Manual Automatic Manual 15 sec 4 min 15 sec Slab in position Pistons down Measurements Pistons up Slab is moving out 6 hours / (4 min/slab) ~ 90 slabs/day ~ 1800 slabs/month

RPC Barrel EDR Chapter 3 3. Production and control of Bakelite Quality control time schedule 1/104/ TASK JulAugSeptOctNovDec JanFebMarAprMayJun Table delivery Setup Ready to measure at firm 5/10

RPC Barrel EDR Chapter 3 3. Production and control of Bakelite Ageing Gamma ( 137 Cs) Irradiation Facility Gamma ( 137 Cs) Irradiation Facility     vs Temp. ( 0 C) (B)    vs Integrated Dose (Gy) A B Source ON Source OFF Melaminic sample 10 y LHC

RPC Barrel EDR Chapter 3 10 y LHC Gamma ( 137 Cs) Irradiation Facility Gamma ( 137 Cs) Irradiation Facility   vs Temp. ( 0 C) (B)    vs Integrated Dose (Gy) A B Source ON Source OFF Phenolic sample 3. Production and control of Bakelite Ageing