A Digital Hadron Calorimeter ?

Vishnu V. Zutshi

NIU/NICADD

The proposal

Development of New Hadronic Calorimetery Technology

G. Blazey, D. Chakraborty, A. Dyshkant, M. Martin,

V. Rykalin, V. Zutshi

NIU/NICADD

A. Brandt, K. De, A. White, J. Yu

UTA

Arrive at a realistic cost estimate for one of these devices

From analog to digital

Eflow seems to be a promising option for improving jet resolutions significantly

ALEPH and CDF have successfully used it Requires a high granularity calorimeter Digital hadron calorimeters: high granularity at

affordable price ?

General Considerations

Granularity (energy and resolving power) MIP recognition Absorber density (optimize shower lateral size) Depth Matching to EM calorimeter Readout (2d preferred to strip type) Minimal intrusions

Energy and position

Too much of a good thing?

Analog and Digital

20 GeV

pions in SD

Single Particle Resolutions

On the software side of things

Prototype simulations:

try out different cell shapes

parameterized losses from test stand

hoping to do this in GEANT4 framework Event generation and LC detector simulation Eflow algorithm development

starting with the EM section

The Algorithm (cal-seeded)

Layer-by-layer clustering based on a search for local maxima

Cluster definition based on nearest neighbour Track extrapolation through the calorimeter

picking clusters in its path EM/HAD. Charged/neutral discrimination Understanding of errors involved with the

tracking and calorimetric measurements

Sanity Checks hi

ts

clusters

Initial concept (scintillator-based)

Four concentric layers of towers (7 stacks of 6-12 cells to a tower) formed with hexagonal cells. Start with 9cm2 cell.

Initial concept (scintillator-based)

Conversion to current:

VLPC’s

APD’s

MRS’s

PMT’s • Cost per channel v/s S/N

Test stand

Cell with WLS fiber irradiated by a radioactive or LED WLS fiber connected to clear fiber which is connected to a photodetector (PMT’s, VLPC’s etc.)Output measured by a Pico ammeter

Test goals

TOP VIEW

Find minimum area/thickness of cellFind minimum length of WLSF

Measure signal losses at the WLSF to clear fiber transition

MIP signal

With VLPC readout9m

m thickness,0.5m

m

fiber,2optical connectors

Initial concept (gas-based)

GEM approach Developed initially for MSGC’s Can be used with printed circuit readout GEM’s with gains above 104 and spark

probabilities < 10-10 have been developed Reasonably fast operation Relatively low HV

Initial concept (gas-based)

Issues/concerns (gas-based)

Cost of GEM layers Lifetime/damage to layers Effects of highly ionizing particles Gas(es) ? Mechanical stability of GEM gaps/supports Cross-talk …..

Summary

Single cell characterization studies have begun GEM based feasibility studies starting soon Event generation and simulation server ready Setting up for GEANT4 based prototype

simulation studies Eflow algorithm development underway