1. Calorimeter Upgrade The Tevatron and Dzero Upgrades
Gregorio Bernardi
on behalf of the
Dzero Collaboration
The Tevatron and Dzero Upgrades
From Run I to Run II, in brief
Preshower Detectors
CPS: design, status...
FPS : expected performances
Calorimeter Electronics
Constraints at Run II
System Description
Intercryostat Detector
Objectives and status

2. Timings Bunch structure Run I 6x6 Run II 36x36
gap used to form trigger
and sample baselines
3.56us
Run I 6x6
superbunch
gap
4.36us
2.64us
396ns
Run II 36x36
this gap is too small to
form trigger and sample
baseline
We expect the bunch structure to evolve to a minimum 132 ns between bunches - design to that
We expect 3 gaps, gap size must be a multiple of 132ns (7 RF buckets)

3. Experiment Physics program at Run II (driven by high pT physics)
Searches for phenomena beyond the SM
Top quark studies
Electroweak measurements
QCD tests
B physics
Accelerator environment implies:
Fast electronics, pipeline
Sophisticated trigger systems
Radiation hard detector components

4. E.M. Calibration
Use J/Psi , Upsilon , Z

5. DÆ Upgrade Forward Scintillator + New Electronics, Trig, DAQ
New Solenoid, Tracking System
SMT, SciFi,Preshowers
Shielding
Forward Mini-drift
chambers
Forward Scintillator
Central Scintillator
+ New Electronics, Trig, DAQ

6. Tracking System Fiber Tracker Silicon Microstrip Tracker Forward
Preshower
Solenoid
Central Preshower

7. Central Preshower Central Preshower already mounted on the solenoid
Scintillator + Lead
Performances studied with MC and cosmic rays

8. Central Preshower Simulation results: Good spatial resolution
Preshower recovers resolution.

9. Forward Preshower Azimuthal wedges (u,v) scintillator/lead with
readout via fibers
side view

10. Fwd Preshower
Azimuthal Wedges ready
Test beam results

11. Fwd Preshower
Test Beam Results (FNAL ‘97)

12. Calorimeter Electronics
Objectives:
Accommodate reduced minimum bunch spacing from 3.5 us to or 132 ns
Storage of analog signal for 4us for L1 trigger formation
Generate trigger signals for calorimeter L1 trigger
Maintain present level of noise performance and pile-up performance
Means
Replace preamplifiers
Replace shapers
Add analog storage
Replace Calibration System

13. Calorimeter Electronics
SCA analog delay
>4usec, alternate
new low noise
preamp & driver
Trig. sum
Bank 0
SCA (48 deep)
SCA (48 deep)
Preamp/
Driver
Filter/
Shaper x1
Output
Buffer
BLS
SCA
Detc. x8
SCA (48 deep)
SCA (48 deep)
Bank 1
Additional
buffering for L2 & L3
Replace cables
for impedance
match
Shorter
shaping
400ns
55K readout channels
Replacement of Preamps, Shapers, BLS, addition of SCA, new calibration.

14. Preamplifier similar to previous version except Dual FET frontend
Compensation for detector capacitance
Faster recovery time
New output driver
for terminated
signal transmission
New calorimeter
preamp, hybrid on
ceramic. Forty eight
preamps on a single
motherboard 2”
FET
driver
preamp

15. SCA Not designed for simultaneous read and write operations
cap ref
input
write address decoder/control
read address decoder/control
..x48..
ref
reset
out
Not designed for simultaneous read and write operations
two SCA banks alternate reading and writing
approximately deadtimeless to L1 rate up to 100kHz
Only 12 bit dynamic range
low and high gain path for each readout channel (X8/X1)
maintain 15 bit dynamic range

16. Calorimeter Electronics Upgrades
Cables from cryostat to preamps
replace 110 ohm cables with impedance matched 30 ohm cables to minimize sensitivity to reflection
Preamp motherboards
48 preamp hybrids per motherboard -- for improved high frequency performance
BLS motherboards/ Crate Controller
48 BLS hybrids/motherboard to accomodate new SCA and shaper
New/additional controls:coordinating the 144 analog samples per channel
Power Supplies
use low noise commercial supplies
power requirements increased
New Calibration System
accommodate timing constraints and have same or better precision.

17. Noise Contributions Reoptimized three contributions Electronics noise:
increases due to shorter shaping times (2 microsnds to 400 ns) (as sqrt(t))
decrease due to lower noise preamp (2 FET input) (as 1/sqrt(2))
Uranium noise:
decrease due to shorter shaping times (as sqrt(t) )
Pile-up noise:
increase due to luminosity (as sqrt(L))
decrease due to shorter shaping times (as sqrt(t))

18. Expected Noise Design for Which leads to Pile-up effect on physics ?
400 ns shaping
lower noise -- 2 FET input
luminosity of 2x1032
Which leads to
electronic noise increase of
uranium noise decrease of
pile-up noise increases by 1.3
comparable noise performance at 1032 with new electronics as with old electronics at 1031
Pile-up effect on physics ?
The W mass “benchmark” has been simulated and confirms that pile-up will not limit our W mass at Run II.

19. Intercryostat Detector (ICD)
Objectives
Maintain ICD performance in presence of a magnetic field and additional material from solenoid
Improve coverage for the region 1.1<eta<1.4
Design
A scintillator based Intercryostat Detector (ICD) with phototube readout similar to Run I design
Expected Physics output
Provides improvement to jet energies and missing energy in the region between the central and end cryostats

20. ICD Design
Detectors
16 super-tiles per end with total of 384 scintillator tiles covering 1.1<eta<1.4
WLS fiber readout of scintillator tiles. Re-use existing PMT’s
Clear fiber light piping to region of low field
Calibration scheme as for L.Ar calo. But with adapted pulse

21. Conclusions Dzero is upgrading its detector
L.Argon calorimeter untouched
Harder machine conditions and new environment (solenoid)
New Calorimeter Electronics
Improved ICD
New Central and Forward Preshower
Similar Performances
Detectors close to be ready to start taking data in Summer 2000