ZEUS experiment 2001

1
ZEUS experiment 2001

• Installation of Microvertex Detector
• Hera upgrade for higher collision rates
• Data analyses

2
Silicon Microvertex Detector

• Proposal, design and construction took 4 years
• February 2001 final transport from NIKHEF to DESY
• Feb/March full system test
• March 27th installation in ZEUS
• July short cosmic run
• December first collision(s)

3
Layout Microvertex Detector
32 cm
electrons
protons
60 cm
Support cylinder divided in 2 halves


Cross section wheel
Cross section barrel
4
Barrel Sensors
2 half modules
Ladder
Detector side
Hybrid side
5
MVD assembly
300 barrel half modules 112
wheel modules 30 ladders
8 half wheels
6
MVD assembly (2 halves)
7
MVD assembly (two halves)
8
Full System test

• 200 k readout channels have to function together
• test final setup for the cabling
• setting/monitoring low voltage front end readout
• setting/monitoring bias voltage sensors
• test complete readout chain analog datalink/ADC,
  triggers for pedestals and testpulses
• cooling
• slow control monitoring
• measure cosmics
• Full system operational, No bad surprises
• about 1 of channels give problems

9
Full System Test

• Cosmic Ray setup at DESY

10
Full System test
E.Maddox

• First Results Reconstruction Cosmic Rays
• Event display
  single track event

11
Full System Test

• First Results Reconstruction Cosmic Rays
• Distribution of residuals track fit obtained
  with default geometry, more survey data to be
  included.

R Phi hits
Z hits
Residual (mm)
Residual (mm)
12
Full System Test

• Response inclined Tracks

clustersum
clustersum
angle beta
1.5 rad
0
clustersum
angle alpha
0
1.5 rad
13
Status of the new tracking software
Detailed Monte Carlo simulations exist for MVD
Impact parameter resolution at vertex for fitted
single tracks
Up to NOW,CTD only
GEANT
With MVD included!
MC tracks
E.Maddox
14
MVD assembly (cooling)
Stainless steel tube
Polyurethane tubes
Manifold water cooling (two mounted on top of
each other, input/output)
15
Cooling Performance

• Monitoring Cooling system as function of Time
  (hor.scale hist. 12 hours)

Switch on low voltage
Water temp. (14C)
Water press (1.6bar)
Humidity in MVD
Temp. ladder 18C
Temp. ladder 18C
Temp. ladder 18C
Temp. in MVD 18C
Temp. in MVD 18C
Temp. wheel 23C
Monitor 1
Monitor 2
16
MVD in ZEUS
Inserted in front (proton side)
Cables at the rear
March 27th 2001 in ZEUS Hall
17
Documentation
4 years of design and construction work
beautifully documented on web page and put on CD
by Marco Kraan
1 year assembly and installation work compiled
on a 25 video by Els Koffeman
18
HERA ZEUS upgrade
Install quadrupoles near interaction
point install spinrotators, long.polarized e-beams
Luminosity x 5 1000 pb-1 end 2005
19
Radiation damage FE electronics
?m

• HELIX chips (AMS 0.8 CMOS)
• tested up to 500Krad
• worse performances (S/N)
• partly recoverable changing operation point

J.Velthuis
Single sensor
20
Monitor Background Radiation
34 mm

• irradiation from IP negligible
• off momentum e- ? g and e- (lt20 GeV)
• Synchrotron radiation, backscattered
  fromcollimators (lt100 keV g)complex pattern
• Proton beam loss (accidents)

28 mm
diodes
Monitor radiation background with pin diodes
near the beampipe inside the MVD.
21
Physics at HERA test and understanding QCD
Proton structure -evolution equations -parton
densities Gluon radiation - first and higher
order Hadronization - many MonteCarlo generators
hard scale high Q2, high ET jets,
high mass...
What do we observe?
DGLAP,BFKL,CCFM,MRS,GRV,CTEQnn,.. HVQDIS,DISENT,J
ETNLO,DISASTER,.. HERWIG,RAPGAP,EPSOFT,PHOJET,LEP
TO, ARIADNE,CASCADE,PYTHIA, DJANGO,HERACLES.
-Diffractive events -Deep inelastic
scattering -multi jet events -heavy quark
production .
22
Proton structure function
e
Q2 four-momentum transfer squared e
x fractional four-momentum of struck quark y
inelasticity

N. Tuning (PhD thesis Sept.2001)
23
Proton structure function F2
N. Tuning
Highest x-bins
24
Proton structure function xF3
HERA II -improve high x,Q2 data
- e-running, balance samples -
progress theory (NNLO), better fits

25
Open Charm Production in DIS
e
Any sign of charm production
S.Schagen
26
Open Charm Production in DIS
Kinematical quantities
S.Schagen
27
Open Charm Production in DIS
Contribution of charm to proton structure
function F2
S.Schagen
28
Beauty Production in Photoproduction
Available data very still very scarce
Reconstruct jets and look for electrons or
muons in jet as function of
HERA II MicroVertex gives proper b- data
MicroVertex gives more
c-decay channels, smaller
Background, smaller kin extrapolations--gt better
measurement
29
More Open Charm Production in DIS
30
More Open Charm Production in DIS
No special triggers required All DIS events
accepted
31
HERA a Charm factory
Just an example

• Use the large number of D collected in ZEUS
  (31K)
• Select Ds1? DK0S ? (K-??S)(??-)
  c.c.
• From the well measured f(c ? D) we get
  the fragment. fraction f(c ? Ds1)

32
HERA a Charm factory
Many new results

• D production in diffractive DIS
• Charm in Photoproduction vs NLO
• Charm dijet photoproduction vs LO and NLO
• Huge D sample in photoproduction
• charm fragmentation universal?
• spectroscopy of D mesons
• probe rare decays
• ..

BUT HERA II MicroVertex
will do better improved triggers

33
(No Transcript)
34
(No Transcript)
35
(No Transcript)
36
(No Transcript)
37
(No Transcript)
38
Proton structure function
Q2 four-momentum transfer squared

x fractional four-momentum of struck quark
y inelasticity
W photon-proton centre of mass energy
39
MVD assembly (two halves)

• Install Beampipe on lower MVD half
• Carbonfiber tube surrounds Beampipe
• protection silicon
• electrical shielding beam
• Turn upper MVD half upside down
• Mount both halves together with help precision
  pins on support frames
• Connect both halves electrically and create
  Faraday cage for the front end readout
• keep supportframes attached until installation in
  ZEUS

40
HERA ZEUS upgrade
Rear end MVD
Super conducting magnet buried in MVD cables