Embed Size (px)
Citation preview
LabCAF Development on Sealed RPCs
Miguel Morales,
February 2010, Santiago de Compostela
Title:(01Logotipo Sigillum PMS 280.eps Creator:Adobe Illustrator(R) 8.0 CreationDate:1/17/2004 10:51 AM
Motivation
Trasgo is a convenient and flexible detector based on gas ionization detectors.
One Trasgo chamber
2010
Motivation
Trasgo is a convenient and flexible detector based on gas ionization detectors.
One Trasgo chamber
Is there any chance to get rid of the gas system to win some flexibility?
2010
Issues with the current gas system
Economic reasons. Gas systems and facilities cost money.
Environmental unfriendly, R134a, SF6 are strong green house effect gases.
Lack of portability. Gas systems have an important weight and volume.
2010
Sealed Resistive Plate Chambers (sRPCs)
40 mm x 40 mm x 4 mm
0.3 mm nylon gapCu Electrodes
Epoxy Glue
Thermoplastic
Float Glass Gas mixture
Some caveats:
Glass borders have to be polished
Some time running a dry gas is needed to extract glass moisture.
Al
Glass
Fishing Line Electrodes Polyestirene Aluminium Foil
Glass
Epoxy Glue
Trasgo proposal
Our first sRPC prototype800 mm x 200 mm x 10 mm
2010
sRPC Overview
SignalSocket
BNC HVSocket
High FrequencyAnalog Amplifier
PT100TemperatureSensor
Aluminum Box
SealedChamber
Two RCCircuits
Standard gas mixtureR134a/SF6/Isobutane85/10/5
2010
Setup
2.2 nFA ADC
[DigitalScope]
Currentmonitoring
10 KΩ
10 MΩ 2.2 nF
3 kV
sRPC
Low-pass RC filter (<3Hz)
High-pass RC filter (>85Hz)
High FrequencyAnalog Amplifier
Analog to Digital Converter
PowerSupply
Digital ScopeTDS7104
CAENN471A
2010
Our Chambers
We have made 10 sRPCs
4 of them have been tested, where:
2 get ruined at the first day (almost no response to 0.5Mbq Na22 radioactive source)
2 were tested in a month time under radiation:
sRPC1: Na22
sRPC2: Cosmic Rays
2010
Measurements on sRPC1
Current
Integrated charge spectra
High Voltage Plateau
2010
Current Trend
sRPc1Reference RPCPT100
2010
Integrated Charge Spectrum
One Day One Week
Three weeks
2010
High Voltage Plateau2010
What might degrade the chambers?
Gas ionization
Gas leaks
Gas concentration gradient
Glue, thermoplastic or tubes gas emissions
???
Gas density (1.013 bar and 15°C)R134A: 4.25 kg/m3SF6: 6.27 kg/m3Isobutane: 2.51 kg/m3
2010
SummarySeveral sealed RPCs has been build and
tested.
Signals mean charge and current increase with time.
High voltage can be decreased to avoid streamers, but loosing gain.
sRPCs working for short-time periods seem to be feasible.
2010
Future workMeasure sRPC resolution and efficiency,
and they evolution.
Use Estrela Front End Electronics and TRB acquisition system.
Asses chamber isolation, and try better building ways.
Asses gas aging, and try better gas mixtures for sRPCs.
Scale things up.
2010
Many thanks to our Summer* students
Nuria Teigel
Diego Ramos
* Summer, Autumn, Winter ...
2010
