1. Status of the RICH project
CSN1 Padova 19th May 2009
Clara Matteuzzi

2. Status of the RICH project
Highlights on what is new since the last report
1. HPD news
2. Commissioning activities
C.Matteuzzi, CSN1 Padova, 19 maggio 2009

3. C.Matteuzzi, CSN1 Padova, 19 maggio 2009
HPD status
T.Gys, Report on HPD status LHCb
The facts:
Out of the 550 HPD tubes, 10% have experienced vacuum problems
47 HPDs in RICH-2 (20 have been replaced in the detector)
1 HPD in RICH (it has been replaced in the detector)
12 HPDs in lab
22 already repaired by Photonis, tested, accepted
(actually most have IFB increase rate 0.07%)
C.Matteuzzi, CSN1 Padova, 19 maggio 2009

4. C.Matteuzzi, CSN1 Padova, 19 maggio 2009
HPD status
Remind few definitions
IFB (Ion FeedBack)  ions originated by e- ionising residual gas atoms
Signature of IFB  cluster size: >=5 Alice pixels
glowing:
When the process ion-electron emission becomes self-sustained
light emission, seen by photocathode and externally
Signatures of self-sustained IFB (glowing):
noise (light) seen during HV ramp-up
at nominal HV, even in dark count run: light cone at tube centre
bias current goes into saturation during light production in HPD
C.Matteuzzi, CSN1 Padova, 19 maggio 2009

5. IFB measurement (cw laser method)
Thresholds of glowing:
no glowing HPD for IFB < 5%
lower threshold at IFB > 5%
i.e. HPDs can turn glowing at any point between IFB=5…8%
full HPD sample
IFB > 5% sample
number of HPD
number of HPD 5%
Ion Feed Back (%)
Ion Feed Back (%)
C.Matteuzzi, CSN1 Padova, 19 maggio 2009

6. C.Matteuzzi, CSN1 Padova, 19 maggio 2009
IFB measurement
IFB vs. age
90% HPD are below 1%
warning threshold
IFB increase per year vs. age:
 90% HPD have
increase<0.5%/year
0.5%/yr 1%
C.Matteuzzi, CSN1 Padova, 19 maggio 2009

7. Lifetime extrapolation
For each HPD look across IFB measurements in RICH 1&2
categorise and fit behaviour
linear fit gives good prediction
Predicted IFB(%)
Measured IFB(%)
(From Ross Young)
C.Matteuzzi, CSN1 Padova, 19 maggio 2009

8. Predictions of IFB Development
HPDs passing IFB = 5% :
~11 HPDs per year
A total of 55 tubes are expected to fail in
the next 5 years
12 in RICH-1
43 in RICH-2 5
RICH1 4 2 1
years 13
RICH2 9 8 7 6
Plan to replace these 20
for september
years
C.Matteuzzi, CSN1 Padova, 19 maggio 2009
C.Matteuzzi, CSN1 Padova, 19 maggio 2009

9. RICH2 – Status Map (before intervention)
27 glowing
10 not glowing IFB>5% already
9 not glowing IFB>5% in 2009
11 not glowing IFB>5% in 2010
8_181
9_101
9_120
9_115 00
8_127
8_153
9_2
9_110 01
8_121
9_10
9_59 02
8_107
9_71
8_179 03
8_112
8_60
9_114 04
8_147
8_177 05
9_127 06
9_155
9_148
8_135
9_181 07
8_133
8_124
9_189 08
9_208 09
9_137
9_12
8_122
9_265
9_69 10
8_160
9_142
8_197
9_56
9_3 11
8_110
8_134
8_154 12
8_156
9_146 13
8_157
8_178
9_15
9_125
9_250
8_176 14
8_119
9_104
8_126
8_141 15
8_130
9_123
9_11
8_108 C0 C1 C2 C3 C4 C5 C6 C7 C8 A0 A1 A2 A3 A4 A5 A6 A7 A8
57 HPDs
C.Matteuzzi, CSN1 Padova, 19 maggio 2009

10. HPD RICH2 replacement summary (intervention march 2009)
40 removed HPDs
32 shipped to Photonis-DEP (with 1 bake-out)
7 with 2 bake-outs
1 recovered, ie with ≥1 bake-out
28 replacement tubes installed
22 repaired
1 reference tube
5 spare tubes from RICH2 spare column
12 anodes installed (no ‘active’ pd)
17 tubes “at risk” for 2009 and to be replaced with the new repaired from Photonis-DEP (if back before august)
C.Matteuzzi, CSN1 Padova, 19 maggio 2009

11. RICH2 – HPDs status (after march intervention)00
8_113
8_163 01
8_153
9_27
8_138 02
8_107
9_114
9_156 03
9_146
8_161
9_203 04
8_60
9_4 05
8_104 06
9_3
10_147
8_135
9_181 07
10_136
9_147
10_157 08
9_187 09
9_42
8_118
8_160
9_265
9_166 10
9_128
10_291
9_101
9_56
10_177 11
10_202
9_223
4_15 12
8_110
8_155 13
9_36
9_124
9_69
9_125
9_240
8_106 14
8_119
8_157 15 C0 C1 C2 C3 C4 C5 C6 C7 C8 A0 A1 A2 A3 A4 A5 A6 A7 A8
replace
by anode
use HPDs
LC>3mA
redeploy
HPDs
repaired &
spare HPD
C.Matteuzzi, CSN1 Padova, 19 maggio 2009

12. RICH2 occupancy map from MonteCarlo
C.Matteuzzi, CSN1 Padova, 19 maggio 2009

13. C.Matteuzzi, CSN1 Padova, 19 maggio 2009
HPD status
An excellent job of systematic understanding of all the measurements
done (IFB monitoring, spectroscopy measurements, measurements of other
type of HPD, temperature dependence,…) has been made
The conclusions are:
The evolution of each tube is under control
all the tubes going bad are predictable
(and they do according to this prediction)
The bad tubes are from the first batches produced
The improvement in the quality seems correlated to the improvement
in QE
C.Matteuzzi, CSN1 Padova, 19 maggio 2009

14. C.Matteuzzi, CSN1 Padova, 19 maggio 2009
Several studies have been performed:
Glow light spectroscopy brightest spectral line seen at 486 nm (hydrogen)
in all glowing tubes tested, also those with no electronics
encapsulated (models PP0380AK, prototypes PP0380V
61-pixel, PP0380AK for BteV)
Visible glow light emission in dark room
 blue glow seen in the center of the quartz window
Temperature effects  intensity of the glow light reduced after cooldown
at -20 oC and stability improved at 18 kV. Glow light return after
heating at 50 oC
Helium permeation tests through HPD quartz window
Glow effect is seen to decrease and finally to switch off when glowing tubes
are annealed for several days with different protocols
Photocurrent and current on grounded electrodes and anode is measured
with negative voltage applied to photocathode. Seen a change in gradient
which can be attributed to a threshold for gas ionization
C.Matteuzzi, CSN1 Padova, 19 maggio 2009

15. C.Matteuzzi, CSN1 Padova, 19 maggio 2009
HPD status
Considering the new schedule of LHC, we have time
(until probably september 2009) to replace the tubes which
are expected to glow in RICH-2 in 2009 and 2010.
This will assure a safe and stable operation of the
RICH detectors for the next long period of running.
Financial aspects:
An agreement with DEP-Photonis has been reached and
all the 100 tubes to be repaired will be shared 50% -50%
between LHCb and DEP
C.Matteuzzi, CSN1 Padova, 19 maggio 2009

16. C.Matteuzzi, CSN1 Padova, 19 maggio 2009
First ‘real data’
C.Matteuzzi, CSN1 Padova, 19 maggio 2009

17. C.Matteuzzi, CSN1 Padova, 19 maggio 2009
BEAM 1
Single event with more than recorded hits
Hits are attributed to Cherenkov light in the vessel, due to beam particle slightly splashing on a collimator
A strong « beam halo light » is visible on the A-side
Photocathode surface is clearly defined (no electronic noise)
All HPDs operational
Number of hits per tube could be more than 2000 (overlaps on pixels) for fully red tubes
C.Matteuzzi, CSN1 Padova, 19 maggio 2009

18. C.Matteuzzi, CSN1 Padova, 19 maggio 2009
Activities in the pit
C.Matteuzzi, CSN1 Padova, 19 maggio 2009

19. Status of the new MDMS systems
Both systems have now also been surveyed.
Both systems have been measured in SSB1
C.Matteuzzi, CSN1 Padova, 19 maggio 2009

20. Photon funnel with MDMS system
The lower photon funnel was installed on February 5th and its operation checked in situ that same week.
The upper photon funnel was installed on February 19th and tests were planned for february 23rd. 20
C.Matteuzzi, CSN1 Padova, 19 maggio 2009

21. C.Matteuzzi, CSN1 Padova, 19 maggio 2009
RICH commissioning
Responsibility has passed from T. Bellunato to
T.Blake and D.Perego (similfellow INFN)
C.Matteuzzi, CSN1 Padova, 19 maggio 2009

22. Rich commissioning and operation
Tests on RICH1 and RICH2 continue:
L0 calibrations
New mask for noisy pixels
Monitored HV ramps
IFB, Calibration, etc runs
MDMS ….
And also :
Control software upgrades going on
Online monitoring improvements
Update of databases
C.Matteuzzi, CSN1 Padova, 19 maggio 2009

23. C.Matteuzzi, CSN1 Padova, 19 maggio 2009
FEST exercise every few weeks successfully used online systems to record and monitor “data”
Hitmaps, DAQ errors, trackless rings
Online monitoring works well
BUT……
Monitoring generally too slow
2D histograms are too big
need to speed optimisation
have to decide on essential monitors
More will be learn and tested at the
Next FEST
C.Matteuzzi, CSN1 Padova, 19 maggio 2009

24. C.Matteuzzi, CSN1 Padova, 19 maggio 2009
Summary
HPDs
Expect to have a stable and efficient detector
Very satisfactory progress in the study and understanding the behaviour of that fraction of HPD with vacuum problems
Work in the pit and commissioning
Major intervention on RICH-1 to install MDMS has been completed (plus other interventions succesfully performed)
Replacement of 27 HPDs in RICH-2 performe in march09
Last repaired HPD will be installed in aug.-sept if they are back from DEP before july
General readiness
RICH in good shape (FEST exercises monitoring/ data quality very useful)
Use of channels for PID calibration in progress (much more at the next general RICH meeting in 1 week)
C.Matteuzzi, CSN1 Padova, 19 maggio 2009

25. C.Matteuzzi, CSN1 Padova, 19 maggio 2009(
C.Matteuzzi, CSN1 Padova, 19 maggio 2009

26. C.Matteuzzi, CSN1 Padova, 19 maggio 2009
Upgrade activities
Upgrade for data at 40 MHz
foresees to change the HPD
and all the front end electronics.
Studies already started and
going on with MaPMT kind of
photodetectors.
C.Matteuzzi, CSN1 Padova, 19 maggio 2009

27. C.Matteuzzi, CSN1 Padova, 19 maggio 2009)
C.Matteuzzi, CSN1 Padova, 19 maggio 2009

28. C.Matteuzzi, CSN1 Padova, 19 maggio 2009