HMPID Project

1
HMPID Project

• Assembly Tests of CsI QE monitors
• VUV-scanner and ASSET
• Milestone December 2002

2

• VUV Scanner
• System for in-situ quality control of large
  area CsI photocathodes (PCs) immediately after
  the deposition scanning measurement of the
  photocurrent produced illuminating PCs with a
  collimated light beam from a VUV deuterium
  source
• concept, design, drawings, production done
• assembly tests done
• ASSET (A Small Sample Evaporation and Test
  facility)
• RD setup
• Characterization of small samples of CsI films
• absolute QE evaluation with a VUV monochromator
  of resolution of 4 nm. The monochromator system
  was designed to be compatible with the UV-system
  of the VUV-scanner (i.e. allow both UV-systems
  to be interchangeable) done
• assembly and tests done

3
? Monitoring - RGA - Temperatures -
Pressures - CsI deposition rates - Witness
samples - VUV scanner (rel. QE)

• Layout of the CERN/HMPID
• CsI deposition plant VUV scanner

4
Auto CAD drawings
Pad cathode mounted on rails
VUV scanner mounted on rails
Reference PM
Protective box
4 CsI sources (in series)
5
Production/assembly/tests ???
6
Before
Now
PicoAmmeter
Multiplexer
D2-lamp
All scanning motions and photo-current readout-ele
ctronics are equipped with a remote control
(NIDAQ/LabView)
Turbo pump
Optics
Primary vac.pump
Inside evaporator ???
7
VUV Scanner platform inside
PC trolley
Anode ring Cathode ring gnd shield
Vacuum feed through (4x)
Rotating Mirror
Horizontal alignment of mirror and anode
Vertical alignment of Ref.PM and anode
Ref.PM housing
8

• Tests, e.g.
• remote control X,Y motion (scan),
• PicoAmp.-readout
• incident UV-spot scan with photo-diode

Optical alignment with laser (e.g. red spot)
9
ASSET A Small Sample Evaporation and Test
facility Previous layout/concept relative QE
determination ? implicit test for VUV-scanner
application OK
P lt 10-5 mbar
sample holder for 2 samples (18x18mm2)
Ref.PM (CsTe)
picoAm.2
S1
S2
picoAm.1
evaporation chamber
UV test chamber
anode grid
UV source
4 interferential filters on rotary disk relative
QE
UV light spot of ? ? 5mm
ASSET upgrade with UV-monochromator absolute QE
measurements ???
10
UV test chamber
Upgrade concept design (compatible with
VUVscanner optics)
Ref PM
Sample holder
Deuterium lamp with quartz exit-window
anode grid
monochromator box (leak- light-tight)
diaphragm
output Argon
UV-mirror
input Argon
MgF2 lens x-y micro-control lens holder
11
System test Deuterium Lamp spectrum D2-peak at
l160 nm is being cut off by the quartz exit
window of the D2-lamp
Upgraded setup is ready
I pA
l nm