electronics for ild mpgd tpc readout n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Electronics for ILD MPGD-TPC readout  PowerPoint Presentation
Download Presentation
Electronics for ILD MPGD-TPC readout 

Loading in 2 Seconds...

play fullscreen
1 / 14

Electronics for ILD MPGD-TPC readout  - PowerPoint PPT Presentation


  • 117 Views
  • Uploaded on

Electronics for ILD MPGD-TPC readout . Madhu Dixit TRIUMF & Carleton University. CERN, October 2009. Rise time for a single cluster determined by electron transit time in the induction gap. GEM charge preamp pulse characteristics. GEM 1. GEM 2. Anode readout pads.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Electronics for ILD MPGD-TPC readout ' - natara


Download Now An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
electronics for ild mpgd tpc readout

Electronics for ILD MPGD-TPC readout 

Madhu Dixit

TRIUMF & Carleton University

CERN, October 2009

gem charge preamp pulse characteristics1

Rise time for a single clusterdetermined by electron transit time in the induction gap

GEM charge preamp pulse characteristics

Ar:CO2/70:30 200 MHz Aleph preamp

3.4 mm induction gap, Vdrift =69 μm/ns

4.5 keVxrays – collimated source in centre

Charge collecting pad

Induced pulses on neighboring pads

tRise(calculated) = 49 ns (transit time) + 40 ns (preamp rise time)

In agreement with experiment

Madhu Dixit

gem readout typical parameters
GEM readout – typical parameters
  • Example: T2K gas, 2 mm induction gap
  • Eind ≈ 3 kV/cm, vdrift= 26 μm/ns
  • Rise time for a single cluster
  • trise ≈ 100 ns [77 ns + 30 ns (charge preamp risetime)
  • For a single cluster, the GEM signal rise time is relatively fast - about 50-100 ns, depending on gas, drift velocity and induction gap.
  • The Micromegas charge signal is due to ion drift, but rise times are similar to those for GEMs.

Madhu Dixit

signal characteristics for ilc tpc
Signal characteristics for ILC TPC
  • All tracks originate for the collision vertex
  • 18-20 clusters (av. 50 electrons) for ~ 6 mm long pads
  • Track angle range 90<  < ~10.
  • Tracks near 90 have the maximum drift ~200 cmTPC with T2K gas at 230 V/cm
  • Longitudinal diffusion 226μm/√cm, vdrift = 76 μm/ns
  • σChargesignal = 3.4 mm for tracks at 90
  • Track charge signal collection time ~185 ns, the time to collect ~ 90% of the charge
  • Similar for small angle tracks near 10
  • Add ~100 ns for intrinsic detector & electronics rise time.
  • To get 100 μm ILC TPC resolution, integration time of ~ 300 ns will be needed

Madhu Dixit

conventional 100 ns peaking tpc pulse processing
Conventional ~ 100 ns peaking -TPC pulse processing

Preamp charge pulse

Shaper response

Τ ≈ 2μs

We decided to digitize charge pulse directly toget full electron signal

MPGD2009

Madhu Dixit

Madhu Dixit

finding the avalanche position on a proportional wire

A geometrical way to use wide MPGD pads with precision

Finding the avalanche position on a proportional wire

Avalanche

x1

x1

Amp 2

Amp 1

Charge division on a proportional wire

Telegraph equation

Deposit point charge at t=0

Solution for charge density (L ~ 0)

Generalize charge division to charge dispersion in 2D

Finding the avalanche location on a MPGD resistive anode surface

Telegraph equation 2-D generalization

Solution for charge density in 2-D

Madhu Dixit

charge dispersion in a mpgd with a resistive anode
Charge dispersion in a MPGD with a resistive anode
  • Modified GEM anode with a high resistivity film bonded to a readout plane with an insulating spacer.
  • 2-dimensional continuous RC network
  • Point charge at r = 0 & t = 0 disperses with time.
  • Time dependent anode charge density sampled by readout pads.
  • Equation for surface charge density function on the 2-dim. continuous RC network:

(r)

Q

(r,t) integral over pads

mm

ns

r / mm

M.S.Dixit et.al., Nucl. Instrum. Methods A518 (2004) 721.

Madhu Dixit

electronics with charge dispersion
Electronics with charge dispersion
  • Integration time with charge dispersion is larger ~ 500 ns
  • Will depend on resistive readout RC

Madhu Dixit

resolution comparison old method vs average 700ns
Resolution comparison: Old Method Vs average(700ns)

Old Method 3652/17669Flat 50 µm Resolution

Independent of z over 15 cm.

New method 5663/17669

Flat 40 µm Resolution

Independent of z.

Madhu Dixit

simulating the t2k with charge dispersion 8 mm x 8 mm pads
Simulating the T2K with charge dispersion ( 8 mm x 8 mm pads)

Anode surface resistivity 150 K/, dielectric gap = 75 m, K = 2

Track at z = 175 mm, x = 0,  = 0 (uniform ionization)

(ns)

(ns)

Pulses with very similar rise/fall times give 0  50 m for 2 x 6 mm2 pads

Madhu Dixit

t2k tpc with charge dispersion readout simulated prf 8 x 8 mm 2 pads
T2K TPC with charge dispersion readout - Simulated PRF 8 x 8 mm2 pads

Pad response function

Relative amplitude

-20

-10

0

10

20

(mm)

Madhu Dixit

slhc micromegas muon chambers
SLHC Micromegas Muon chambers

Capacitance 100 pF/cm^2 for 100 micron gap

 Strip width = 1 mm = 0.1 cm

Assume 50 cm long strips = > Area = 5 cm^2 => capacitance 500 pF

Will need to use MOSFET, since one can get better trans-conductance => faster risetime at larger capacitance

MOSFET can be incorporated readily as part of ASIC, and can be made with radhard process

Will need big MOSFET. One can live with that since high density readout is not needed

Front-end preamplifier risetime better than 100 ns under these conditions

For charge dispersion, risetime will determine pulse pair resolution in case of pulse pileup on long strips

Consider area of 2 strips = > 10 cm^2 for pileup considerations

Muon chamber rates 1E4/(sec.cm^2) max

Count rate for 10 cm^2 area => 1E5/sec =0.1 hit/micro.sec = 10 micro.sec between hits

Assume resolving time = 100 ns

nbar = average rate per 100 ns = 0.01

P(n) = exp(-nbar). (nbar)^(n)/n!

P(0) ~ 0.99

P(1) ~ 0.01

P(2) ~ ~0.01*0.01/2

Pile up probability ~ 0.01 => 1%

1% of hits will be unresolved at this rate.

Resolution achievable should be better than 100 microns

Madhu Dixit