OPERA Collaboration Meeting

1
RPC
Status Report

• RPC installation and testing
• .RPC production
• .Strips production and assembling
• .RPC tests in Lab2 at Gran Sasso

2
RPC-wall-numbering
12,13,22
12,13,22
1,2,3,11
1,2,3,11
beam
Spectrometer I
Spectrometer II
3
INSTALLATION first timing
November

• Week for learning (and Iron rectification)
• Week for setting up infrastructure
• First RPC-wall (no. 12) completed !!
• Week for 2nd RPC-wall (no. 11)
• Week for assembling infrastructure II
  Spectrometer
• Week for first 2 iron-walls II Spectrometer
• Week for second wall I Spectr. and learning on
  closing RPC
• Stop
• Stop
• Stop
• Rectification second 2 iron-walls I Spectrometer
• Installation RPC-walls no. 10,13. (Fill, HV
  -1.523 d)
• End Installation RPC-wall no. 10,13. (Workers -1
  d)
• Third 2 iron-walls I Spectrom. Start RPC-walls
  9,14
• End RPC-walls 9,14. fourth 2 iron-walls I Spectr.

2003
December
January
2004
NOW
4
SCHEDULE
Tentative Installation Timing (for 2 walls at the
same time)
1rst week
2nd week
5
Week 2 January 5th, Monday Week 3 Week 4 Week
5 Week 6 Week 7 Week 8 Week 9 Week 10 Week
11 Week 12 Week 13 Week 14 Week 15 Week 16 ?
Easter Week 17 Week 18 Week 19 Week 20 Week
21 Week 22 Week 23 Week 24 June 7th, Monday
Installation 1rst Spectrometer
Walls 10,13
Walls 9,14
NOW
If time contingency will be available installation
of 2nd Spectrometer will be going on
Walls 8,15
Walls 7,16
Otherwise, for the 2nd Spectrometer 22 weeks
Walls 6,17
Walls 5,18
without considering interferences with
TOP-Spectrometers and WALLS installations
Walls 4,19
Walls 3,20
ManPower RPC 1 senior physicist per week -
Brugnera, Stanco, Terranova - (Garfagnni,
Spinetti) 2 technicians 1 Arcobaleno 6 workers (4
on installation, 2 on preparation)
Walls 2,21
Walls 1,22
6
SCHEDULE
RPC TEST Timing
1rst week
2nd week
Tested 36 RPC
Ready 50 RPC
7
ManPower 1 young-physicist/technician 7 day per
week 2 workers Several Experts available in the
week - pushing (Carrara) - Conditioning
(Paoloni) - Cosmics (Dusini) - Trigger walls
(Candela, DIncecco) - DAQ (Lindozzi)
8
Week 2 Jan. 5th, 195 RPC tested OK, (42
installed, 6 rejected, 147 available) Week 3
25 tested OK (172 ready) Week 4 25 tested OK
(197 ready, 42 installed, 4 rejected ), 151
available Week 5 25 tested OK (176 ready) Week
6 25 tested OK (201 ready, 42 installed, 4
rejected), 155 available Week 7 25 tested OK
(180 ready) Week 8 25 tested OK (205 ready, 42
installed, 4 rejected), 159 available Week 9 25
tested OK (184 ready) Week 10 25 tested OK (209
ready, 42 installed, 4 rejected), 163
available Week 11 25 tested OK (188 ready) Week
12 25 tested OK (213 ready, 42 installed, 4
rejected), 167 available Week 13 25 tested OK
(192 ready) Week 14 25 tested OK (217 ready, 42
installed, 4 rejected), 171 available Week 15
25 tested OK (196 ready) Week 16 ? Easter Week
17 25 tested OK (221 ready, 42 installed, 4
rejected), 175 available Week 18 25 tested OK
(200 ready) Week 19 25 tested OK (225 ready, 42
installed, 4 rejected), 179 available Week 20
25 tested OK (204 ready) Week 21 25 tested OK
(229 ready, 42 installed, 4 rejected), 183
available Week 22 25 tested OK (208 ready) Week
23 25 tested OK (233 ready, 42 installed, 4
rejected), 187 available Week 24 June 7th, Monday
1/3 II-Spectr.
9
SUMMARY on RPC installation

• 84 detectors fully installed
• 4 of them with electrical problems
• HV problems solved
• (reasons under investigation, solutions for
  preventing, too)

• RPC installation fully integrated with Iron
• schedule (almost) under control 1 wall
  RPCIron/week
• room for time gaining (on 2nd Spectrometer)
  possible

• need to verify full capability of the detectors
• need for permission to use (small quantity of)
  gas in Hall C
• put LNGS burocracy under pressure (Piero
  Monacelli)

10
PRODUCTION

• end production 1rst Spectrometer in June 2003
• INFN signed contract for RPCs 2nd Spectrometer
• production 2nd Spectrometer started in October
• end foreseen for May 2004 (incl. contingency and
  XPC)

Type A
6 different types of Chambers
AE AI AE BE BIM BE BES BI - BES
8 meters
Type B
Problem in selection, but it was well recovered
8.75 meters
(around 120 BE produced , to take care of)
11
OPERA RPC _at_ General Tecnica

• Production for 1st Spectrometer ended
• 9.1.2003 ? 22.7.2003 578 RPC assembled
• Production for 2nd Spectrometer started in
  October (due to INFN administrative delays)
• 13.10.2003 ? May.2004 265 RPC assembled in 3
  months. Due to INFN-RPC committee planning,
  expect to finish production end of May 2004 (with
  all spares and XPCs).

12
HPL production (bakelite)
HPL for the 2nd spectrometer has been ordered and
is in production. (800 layers delivered in fall
2003, production will be completed during the
first months of 2004). Warning Gluing problems
may reappear in January 2004 (iron slabs, used
for HPL pressing have been re manufactured ?
residuals may affect quality of HPL. Problems
seemed to have happened in similar conditions in
the past we do not have a complete control of
the process).
13

• Polipropyline produced once a time (end of May
  2003)
• Table for polipropyline cut finally satisfactory
• decided method for hole surrounding
• production going very well
• roughly 11/3 all strips ready
• end in March 2004

STRIPS
14
STRIPS

• learning time for soldering (October 15th
  30th)
• installation of vertical strips begin November
  2003
• installation of horizontal strips showed some
  difficulties
• - NO WAY to glue together H-strips and RPC due
  to
• further iron slab positioning
• - filling of air gap more problematic
• defining final procedure on middle December 2003

What about XPC strips ?
15
SYSTEM TEST
1
2
Mechanical test
Electrical test
485 Chambers tested, i.e. almost all those
Needed for the I Spectrometer
Conditioning properly working 48 chambers under
test at once
16
3
Efficiency test
17
Cosmic ray test setup
4x4 m2 Glass RPC for trigger and tracking

• 36 OPERA RPC under test
• Horizontal and vertical strips with 3.5cm pitch
  and digital readout.
• In total 5000 channels
• The current of each RPC measured with 2nA
  resolution and monitored during the test.
• Gas
• 12 parallel lines
• 3 RPC in series (like in OPERA detec.)
• 48 Ar, 48, 4 isobutane

??
252 RPC so far tested All results here presented
are base on 108 RPC
18
What we measure

• RPC efficiency
• Average RPC efficiency vs. HV
• Local efficiency in bin 7 x 7 cm2
• Single Rate
• Single Rate vs. HV
• Map of the noise inside RPC
• Currents
• Stability of the currents during test

19
Situation

• 288 RPC tested
• 252 RPC results available 32 under analysis
• Up to now no major problems
• The time needed to perform all the test is 7
  days including
• Preparation of the test - 1 day
• Dismounting 1 day
• Debug/repair electronics 1 day
• Contingency 1 day
• Data analysis require 2 days
• No DataBase yet

20
Efficiency Curve
Example of efficiency curve of RPC of batch 3
The efficiency curve are fitted
with eff1-s-exp(-(abHV)) s ineff. of spacer
The parameters s,a,b will be used as measure of
the goodness of the RPC
Only one RPC shows high value of a and b
21
Efficiency Curve
The efficiency curve are fitted
with eff1-s-exp(-(abHV)) s ineff. of spacer
Example of efficiency curves of RPC of test batch
3 Norm. T200 C, P900 mbar

• The parameters s,a,b used as measure of RPC
  goodness
• Only 1 RPC shows high value of a and b and has
  bee rejected

22
With high statistic runs (3M events) we make a
radiography of RPC with 0.8 cm resolution
Distribution of points where RPC is inefficient
Mean efficiency averaging over RPC surface
Spacer
Based on 252 tested RPC

• Average eff 0.97
• Efficiency uniform over RPC surface within few

All RPC show high and uniform efficiency
Local efficiency in bin 7x7 cm2 stat. err. lt 1
23
RPC Single Rate
Single rate measured counting the Digital OR of
the 32 ch FE card.
Single rate vs. HV nor. T200C P900mbar
RPC Single rate _at_ HV7.6 kV (T200C P900mbar)
224 tested RPC ltrategt 597 Hz

• Almost all RPC have less 1 kHz (lt300 Hz/m2)
• Only one RPC with very high rate
• The improved oil coating of OPERA production has
  reduce the internal noise

24
Triggering on the OR of the strips of a single
RPC we make maps of the RPCinternal noise

• plots made with fixed number of events (50000
  ev)
• HV 7.6 kV

Normal RPC
RPC side with grovesis more noisy
Almost all noise in a single cell
25
RPC Noise Map (II)

• Criteria to classify RPC
• R fraction of events in one bin
  (3.5x3.5 cm2)
• If Max(R)lt0.003 ? Very Good RPC
• If 0.003 lt Max(R) lt 0.01 ??Good RPC
• If Max(R)gt0.01 ? RPC rejected
• Rejection Factors
• 25 Very Good
• 55 Good
• 20 Rejected

Distribution of the Hot Spot (Rgt0.01)

• No special location of the HS except
• Gas inlet with groove
• Near the groves

26
RPC Currents
252 tested RPC

• RPC currents are constantly measured during the
  test using 3 OPERA 16 ch HV distributor with nano
  Amperometers embedded.
• At HV7.6 kV ltcur.gt ??
• Almost all RPC have lt 1 ?A
• No RPC reject due to high currents
  (Conditioning)

Ratio Current/Rate
The gas system is stable in time
Num. RPC
Time
27
Summary
The RPC cosmic test facility has been fully
commissioned and is now completing the QC test
for the RPC of the 1st spectrometer. The noise
map test has the highest rejection factor (20)
but we still have to fully understand the output
of the test.
28
QC test summary
29
RPC type AE prod/test summary
30
RPC type AI prod/test summary
31
RPC type BE prod/test summary
32
RPC type BIM prod/test summary
33
RPC type BI prod/test summary
34
RPC type BES prod/test summary
35
ELECTRONICS

• going very well
• started pre-series of FEB
• 1rst prototype controller ready
• full system test in Naple under way

36
SUMMARY on RPC testing

• tests procedures well under control
• large rejection from noise-cut (about 20)
• under investigation the possibility to be
  eventually less conservative

• release of about 25 RPC per week
• tight constraint on needs for installation (21
  per week)
• large number of RPC already released from
  September 2003
• problems with handling and space in Hall C

37
Enormous effort from all the people involved in
the RPC/Iron business.
I am really proud to work with them and
I really thank all of them !!