1. Sealed RPCs: The LIP approach
P.Fonte
LIP- Coimbra

2. Objective:
Develop a large area sealed RPC detector that may be
used for cosmic ray experiments and Outreach activities.
Inexpensive
Modular (easy maintenance)
TOF-quality timing
1st prototype built in August 2009
Learning process ongoing…

3. Mechanics
100.00
4 mm acrylic
5 2mm glass
m 10.00
m
4 mm acrylic
External (independent)
readout electrodes
K7 approach

4. 1st prototype
1m2
Under test since August

5. Performance so far (example)
600 1025
Pressure (mbar), Temperature (a.u.)
500
1020
400
Corrente (nA)
1015
300
Background current 1010
200
Counting current
Temperature
pressure
1005
100
0 1000
12-01-10 14-01-10 16-01-10 18-01-10 20-01-10 22-01-10 24-01-10 26-01-10 28-01-10 30-01-10
Chamber sealed Date
The contamination is internal. We made VERY sure there is no macroscopic leakage.
Best guess (my version): air trapped in adesives and/or under foils. If so, should go
away after a few cleaning cycles. Obvious alternative: outgassing from materials.