The primary goal has been to have the AFP timing system fully defined for the AFP Technical Proposal...

The primary goal has been to have the AFP timing system fully defined for the AFP Technical Proposal by December 2010.

The end result should be a system that can obtain 20 ps resolution at an instantaneous luminosity of 1033 and given funding could be built and installed by mid/late 2012, and a second stage system capable of 10 ps or better resolution at an instantaneous luminosity of 1034 and given funding could be built and installed by 2015.

Andrew Brandt (UTA) AFP Workshop Prague

1Sep. 6, 2010

AFP Fast Timing OverviewAndrew Brandt, University of Texas at Arlington

Timing System Requirements• 10 ps or better resolution• Acceptance over full range of proton x+y• Near 100% efficiency• High rate capability• Segmented : for multi-proton timing and L1 trigger• Robust: capable of operating with little or no intervention

in radiation environment (tunnel) - PMT’s, detectors, cables, and electronics must be able to

tolerate radiation levels (for PMT’s this includes tolerance to external radiation damage, as well as to internal photocathode damage)

- Backgrounds from other particles must not impair operation


2Sep. 6, 2010

FP420 Baseline Plan1 GASTOF 2 QUARTICs

Lots of 3D siliconTwo types of Cerenkov detector are employed:

GASTOF – a gas Cerenkov detector that makes a single precise measurement

QUARTIC – two QUARTIC detectors each with 4 rows of 8 fused silica bar allowing up to a 4-fold improvement over the single bar resolution

Both detectors use Micro Channel Plate PMTs (MCP-PMTs)3Sep. 6, 2010 Andrew Brandt (UTA) AFP Workshop

Prague

4x8 array of 5x5 mm2 fused silica bars

QUARTIC is Primary AFP Timing Detector

Multiple measurements with “modest” resolution simplifies requirements in all phases of system1) We have a readout solution for this option 2)We can have a several meter cable run to a lower radiation area where electronics will be located3)Segmentation is natural for this detector4)Possible optimization with fibers instead of bars—discuss later

proton

phot

ons

Only need a 40 ps measurement if you can do it 16 times: 2 detectors with 8 bars each, with about 10 pe’s per bar

4

UTA, Alberta, Giessen, Stonybrook (w/help from Louvain and FNAL)

Sep. 6, 2010 Andrew Brandt (UTA) AFP Workshop Prague

5

Micro-Channel Plate Photomultiplier Tube

Burle/Photonis 64 channel 10 or 25 m pore has been tested extensively with test beam and laser and would be default for first stage except for lifetime issues

MCP-PMT RequirementsExcellent time resolution: 20-30 ps or better for 10 pe’s High rate capability: Imax= 3 A/cm2

Long Lifetime: Q = 30 C/cm2/year at 400 nmMulti anode: pixel size of ~6 mm x 6mm Pore Size: In our experience need 10 m or better Tube Size: 40 mm round, 1 or 2 inch square

Need to have capability of measurements in different parts of tube between 0-2 ns apart, and in same part of the tube 25 ns apart 6

Photek240 (1ch)

HamamatsuSL10 (4x4)


Dt

QUARTIC Timing 2008 CERN TB

56.6/1.4=40 ps/bar using Burle 64 channel 10 mpore tube including CFD!

Time difference between two 9 cm quartz bars after Louvain constant fraction implies a single bar resolution of 40 ps for about 10 pe’s (expected 10 pe’s from simulations). Need to demonstrate N (more later)

Npe=(area/rms)2

7

2 21 2 1

1

( ) ( ) 2

so if 1 2 then / 2

t t t t

t t

6 mm

6mm

Eve

nts

Strip #

Eff

icie

ncy

(a) (b)

(c)

QUARTIC Efficiency CERN TBAll tracks(Bonn SiliconTelescope)

Tracks witha Quartz bar on

Use tracking (b)/(a) to determine that QUARTIC bar efficiency is high and uniform

Shape due to vetocounterwith 15mmdiameterhole

8Sep. 6, 2010 Andrew Brandt (UTA) AFP Workshop Prague

Beam Mode Fiber Mode

(a)

(b) (d)

(c)

9

UTA Laser System


Time Resolution from Laser Tests


10Laser tests of 10 µm tube show that with sufficient amplification there is

no dependence of timing on gain (low gain operation extends lifetime of tube)


11

Saturation from Laser Tests

Saturation independent of number of pixels hit,

with proposed glass can obtain required rate


12

Electronics Layout

LCFD

LCFD (Louvain ConstantFraction Discriminator)•12 channel NIM unit•mini-module approachtuned to PMT rise time•Excellent performance : <10 ps resolution for 4 or more pe’s•<5 ps for 10 pe’s

Remote control for threshold

ZX60 4 GHz amplifier(we use pairs of amps in different combinationsto control total amplification)


Alberta has created modified version (ALCFD) with LVPECL output to operate w/HPTDC board

Alberta HPTDC board

12 ps resolution with pulser including non-linearity corrections. Successfully tested at UTA laser test stand with laser/10 m tube/ZX60 amp/ALCFD (and in TB)

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LCFD_Ch01_No12_spe, high level light, May 6, 2009, UTA laser test RMS resolution = 13.7 ps

0

1000

2000

3000

4000

5000

6000

800 810 820 830 840 850 860 870 880 890 900

bin number

coun

ts

14 ps resolution in laser tests

Jim PinfoldShengli Liu



15

Reference TimingReference timing is needed to connect two arms ~1km apart; what we want is TL-TR, what we measure is (TL-Tref)-(TR-Tref), so need small jitter in Tref

This setup has just been tested to give <10 ps (over 20 C range) with 1000 ft cable

The reference system uses a phase lock loop to maintain a constant number of wavelengths in a 100m cable. This synchronizes the phase of the RF at each end of the cable. A voltage controlled oscillator (VCO) launches a signal down the cable where it is reflected and sent back. The returned signal is then interfered with an external RF reference to synchronize it with the reference. At the end of the 100m cable the signal is sampled with a directional coupler which mixes the signal to produce a DC level. That DC level is fed back to the VCO to maintain a constant number of wavelengths in the cable.

Lifetime IssuesLifetime due to positive ions damaging the photocathode is believed to be proportional to extracted charge: Q/year = I*107 sec/year Q for 3 A/cm2 is 30 C/cm2/yr

Can reduce this requirement with fiber detector but still off by at least a factor of 20, so developed an R&D plan to pursue this


16Sep. 6, 2010

Options for Improved Lifetime MCP-PMTIon barrier, already demonstrated, this promises a factor 5 to 6 lifetime

improvement (at the cost of a 40% collection efficiency reduction)

Electron scrubbing, already demonstrated internally by Photonis, promises a factor 5 to 10 lifetime improvement

Z-stack, already demonstrated, this promises a factor of 10 lifetime improvement (A.Yu. Barnyakov, et al., Nucl. Instr. and Meth. A 598 (2009) 160)

Arradiance coated MCP’s, to be demonstrated, this promises a factor of 10 or more lifetime improvement

Various combinations of these factors are possible and should give multiplicative improvement factors, except for the electron scrubbing and Arradiance coating, which would be expected to be orthogonal


Pursuing funds to commission, purchase, and test longer lifetime tubes. Photek will build tubes to our specification, Photonis will insert Arradiance modified MCP into their tubes.

No Funding (yet)!

Possible Showstoppers for TP

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1)PMT Lifetime. I have developed a detailed plan to addressthis issue and believe the problem is solvable with funding and cooperation from PMT vendors. NO funding, so no solution. Will not have a solution within the next couple years at this point. Nagoya’s SL10 4x4 with ion barrier between MCP’s is best existingoption and might work for 1033 phase (not tested by us yet).

2)Background from halo protons interacting in beampipeand contaminating timing measurement. This urgently needsattention and no one is working on it!!!

3) Radiation damage to electronics (needs manpower)4) Latency (needs studies from LAr)


Issues for Technical Proposal

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1) Detector optimization:

a) quartz fibers (Giessen, Alberta): this would allow finer binning near the beam where rate is highest. Instead of four 6 mm bins, propose 1.5, 3, 6, 12.

Would need to defuse light from smaller bin and focus light from larger bin to fit into same size pixel.

b) Need design with no cracks between rows

c) Need to test filtering of high wavelengths for use with solar blind photocathode.

2) QUARTIC Electronics

- rad hard amplifier

- PMT to amplifier cables, amplifier board

- Location of CFD’s

- Location of HPTDC boards

- 80 MHz or 160 MHz HPTDC? high res HPTDC?

- NINO chip

- interface to ROD


Issues for Technical Proposal

20

3) GASTOF Electronics (?)

-default is to plug into QUARTIC chain (degrades resolution)

-sampling chip?

-rad hardness?

-multi-anode design?

4) Reference Timing (Jeff Gronberg LLNL +SLAC, +UTA EE?)

-optimizing clock/cable

-interface electronics

-temperature control of cable

5) L1 Trigger -provided by LCFD coincidence (Alberta+?)

6) Cabling of full chain (?)

7) LV/HV (?)


Aug 23-30 CERN Test BeamQUARTIC: New quartz bar prototype test (Alberta 8 long-bar prototype), use scope to measure raw signal

and compare to laser, pulse height, number of pe’s, timing resolution 8 channel electronics test AMP->CFD->HPTDC [sqrt(N) test] study coherent noise effects and 8-channel timing compare 25 um and two 10 um Burle tubes (single channel and also 8 channel) Color dispersion tests with long bar and filter (need to borrow photek tube for this)[not done]

GASTOF: Resolution for Hamamatsu type Gastof [no Photek tubes available]

FIBER: Giessen fiber detector with Giessen readout Repeat for QUARTIC readout Alberta fiber bundle comparison tests

218/18/2010 Andrew Brandt UTA Test Beam Planning

ANALYSIS IN PROGRESS

Alberta Electronics Plan

• Alberta has copied and upgraded Louvain CDF and developed HPTDC board

• Goals:

-Complete design of a 3 HPTDC chip, 8 channel HPTDC board based on successful one chip design (due to occupancy issues only 4 channels available per chip, and one of those is used for reference timing, so a 3 chip board gives 8+1 channels)

-Documentation and further system tests, including connections with ROD

• Manpower:- Jim Pinfold- Shengli Liu (main Electrical Engineer)

5/26/2010 Andrew Brandt UTA 22

Stony Brook Electronics Plan

• Goals: - Tests of chain PULSER==>Preamp==>CFD- SPICE model of the chain PreAmp==>CFD==>Trigger- test of trigger circuitry- detailed design of PreAmp PCB- detailed design of Trigger circuitry

• Manpower:- Michael Rijssenbeek - Dean Schamberger: Design/consultations/supervision - Jack Steffens - Senior Tech: PCB and jigs- Taklam Li (Physics undergrad) - Fall- 1-2 REU students - Summer.


UTA Laser Plan• Goals:

- Finish cross talk and multi-proton studies

- 2nd 10 m tubes evaluation,

- Borrow SL10?- Submit results of these and other laser studies over the past 1.5 years to J. Inst (this also includes detailed studies of timing of Burle 10 and 25 m tubes, Saturation/Rates, Photek tube - Lifetime tests?

-Photek Tests?

• Manpower:- Andrew Brandt- Ian Howley (Ph. D. student), Ryan Hall (was UG, entering UTA Ph. D. program)

- Monica Hew, Keith Gray, James Bourbeau+… (UG)


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We have developed a fast timing system for AFP that seems to be capable of ~10 ps resolution, still some loose ends to address

Work in progress:

1) final optimization of detector (quartz fibers could lower maximum rate by 2-3 by more sensible binning)

2) developing final HPTDC board and trigger circuit

3) test beam analysis and laser tests (including studies of multiple proton effects, lifetime)

4) developing and testing long-life MCP-PMT (no funding)

5) evaluating radiation tolerance of all components and upgrading as needed

6) SiPm alternative (Rhonzhin, Albrow)

Plan to write-up results for Technical Proposal

Conclusions

The primary goal has been to have the AFP timing system fully defined for the AFP Technical Proposal...

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