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The DarkLight experiment
Jan C. Bernauer
APEX collaboration meeting, April 2015
1
CollaborationR. Alarcon, D. Blyth, R. Dipert, L. Ice, G. Randall
Arizona State University, Phoenix, AZ
B. Dongwi, N. Kalantarians, M. Kohl, A. Liyanage, J. Nazeer
Hampton University, Hampton, VA
S. Benson, J. Boyce, D. Douglas, P. Evtushenko, C. Hernandez-Garcia, C. Keith,
C. Tennant, S. Zhang
Thomas Jefferson National Accelerator Facility, Newport News, VA
J. Balewski, J. Bernauer, J. Bessuille, R. Corliss, R. Cowan, C. Epstein, P. Fisher*, D. Hasell,
E. Ihloff, Y. Kahn, J. Kelsey, R. Milner*, S. Steadman, J. Thaler, C. Tschalär, C. Vidal
MIT, Cambridge, MA
M. Garçon
CEA Saclay , Gif-sur-Yvette, France
R. Cervantes, K. Dehmelt, A. Deshpande, N. Feege
Stony Brook University, Stony Brook, NY
B. Surrow
Temple University, Philadelphia, PA
To come: Johannes Gutenberg University, Mainz, Germany
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Current and future exclusion limitscurrent future
invi
sible
visib
le
3
Design goals
Measure e−+p −→ e−+p +A′ −→ e−+p + (e+ +e−)100 MeV beam =⇒ below pion threshold, simple finalstateComplete reconstruction of final state: e+e−pair fromdecay, scattered electron, recoil proton=⇒ large acceptance=⇒ proton only has 1-5 MeV =⇒ gas targetResolution of reconstructed A′ of 1-3 MeVFinal state leptons 10-100 MeV =⇒multiple scatteringdominant =⇒minimize material0.5 Tesla solenoidal magnet for momentummeasurement and to bottle up Møller electronsDefinitive measurement in about 1 month: highluminosity: 10 mA @ 1019 Atoms/cm2
=⇒ JLAB LERF world’s only such accelerator
4
JLab LERF
Low Energy Recirculating FacilityEnergy recovering linacup to 10 mA @ 100 MeVMegawatt beam
5
Successful beam test July 2012
Target systemdesigned andconstructed atMIT-Bates R&E
center
4.3 mA, 100 MeV (430 kWatt beam power) transmittedthrough 2 mm hole, 127 mm longMaximum loss of 3 ppm in 7 hoursERL has required stability
Phys. Rev. Lett. 111, 165801 (2013)Nucl. Instr. Meth A729, 233 (2013)Nucl. Instr. Meth. A729, 69 (2013)
6
Phased approach
Phase 1Accelerator studiesMeasure SM physics / detector testPilot DM search
Phase 2Full DM searchInvisible searchFull streaming readout
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J. Balewski et al., arXiv:1412.4717 [physics.ins-det]
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Detector setup
Procured existing magnet0.5 Tesla max fieldInner diameter 712mmNow at MIT-Bates
Hydrogen gas targetThickness: 1019 Atoms/cm2
2mm apertures to limit flowMultiple stages of pumping1mm thin berrylium pipeInvestigating jet target
12 ladders, 6 sensors each300 µm thicknessExperience from STAR IST
Thin, high rate capableCylindrical detectorspossible
9
Solenoid magnet
TargetProton silicondetectorLepton tracker4 layers MicroMegasDesign is still in flux!
Detector setup
Procured existing magnet0.5 Tesla max fieldInner diameter 712mmNow at MIT-Bates
Hydrogen gas targetThickness: 1019 Atoms/cm2
2mm apertures to limit flowMultiple stages of pumping1mm thin berrylium pipeInvestigating jet target
12 ladders, 6 sensors each300 µm thicknessExperience from STAR IST
Thin, high rate capableCylindrical detectorspossible
10
Solenoid magnet
TargetProton silicondetectorLepton tracker4 layers MicroMegasDesign is still in flux!
Detector setup
Procured existing magnet0.5 Tesla max fieldInner diameter 712mmNow at MIT-Bates
Hydrogen gas targetThickness: 1019 Atoms/cm2
2mm apertures to limit flowMultiple stages of pumping1mm thin berrylium pipeInvestigating jet target
12 ladders, 6 sensors each300 µm thicknessExperience from STAR IST
Thin, high rate capableCylindrical detectorspossible
11
Solenoid magnetTarget
Proton silicondetectorLepton tracker4 layers MicroMegasDesign is still in flux!
Detector setup
Procured existing magnet0.5 Tesla max fieldInner diameter 712mmNow at MIT-Bates
Hydrogen gas targetThickness: 1019 Atoms/cm2
2mm apertures to limit flowMultiple stages of pumping1mm thin berrylium pipeInvestigating jet target
12 ladders, 6 sensors each300 µm thicknessExperience from STAR IST
Thin, high rate capableCylindrical detectorspossible
12
Solenoid magnetTarget
Proton silicondetectorLepton tracker4 layers MicroMegasDesign is still in flux!
Detector setup
Procured existing magnet0.5 Tesla max fieldInner diameter 712mmNow at MIT-Bates
Hydrogen gas targetThickness: 1019 Atoms/cm2
2mm apertures to limit flowMultiple stages of pumping1mm thin berrylium pipeInvestigating jet target
12 ladders, 6 sensors each300 µm thicknessExperience from STAR IST
Thin, high rate capableCylindrical detectorspossible
13
Solenoid magnetTargetProton silicondetector
Lepton tracker4 layers MicroMegasDesign is still in flux!
Detector setup
Procured existing magnet0.5 Tesla max fieldInner diameter 712mmNow at MIT-Bates
Hydrogen gas targetThickness: 1019 Atoms/cm2
2mm apertures to limit flowMultiple stages of pumping1mm thin berrylium pipeInvestigating jet target
12 ladders, 6 sensors each300 µm thicknessExperience from STAR IST
Thin, high rate capableCylindrical detectorspossible
14
Solenoid magnetTargetProton silicondetector
Lepton tracker4 layers MicroMegasDesign is still in flux!
Detector setup
Procured existing magnet0.5 Tesla max fieldInner diameter 712mmNow at MIT-Bates
Hydrogen gas targetThickness: 1019 Atoms/cm2
2mm apertures to limit flowMultiple stages of pumping1mm thin berrylium pipeInvestigating jet target
12 ladders, 6 sensors each300 µm thicknessExperience from STAR IST
Thin, high rate capableCylindrical detectorspossible
15
Solenoid magnetTargetProton silicondetectorLepton tracker4 layers MicroMegas
Design is still in flux!
Detector setup
Procured existing magnet0.5 Tesla max fieldInner diameter 712mmNow at MIT-Bates
Hydrogen gas targetThickness: 1019 Atoms/cm2
2mm apertures to limit flowMultiple stages of pumping1mm thin berrylium pipeInvestigating jet target
12 ladders, 6 sensors each300 µm thicknessExperience from STAR IST
Thin, high rate capableCylindrical detectorspossible
16
Solenoid magnetTargetProton silicondetectorLepton tracker4 layers MicroMegas
Design is still in flux!
Detector setup
Procured existing magnet0.5 Tesla max fieldInner diameter 712mmNow at MIT-Bates
Hydrogen gas targetThickness: 1019 Atoms/cm2
2mm apertures to limit flowMultiple stages of pumping1mm thin berrylium pipeInvestigating jet target
12 ladders, 6 sensors each300 µm thicknessExperience from STAR IST
Thin, high rate capableCylindrical detectorspossible
17
Solenoid magnetTargetProton silicondetectorLepton tracker4 layers MicroMegasDesign is still in flux!
Kinematics
, Can detect full final state, Large acceptance/ How to trigger?
Signal tracks do not reach beyond lepton trackerCan not identify reaction on trigger levelCan not trigger on ”3 particles”: background tohigh
18
Background rates: Elastic scattering
90 patchesindependent2D strip readout>20 tracks every 25 ns frame
19
Normal electronics
Trigger
APV
64..256 Channels
ADC
APV/DREAM/... multiplex N channels to 1 ADCTheoretical maximum readout rate: 1/N of ADC clock
20
Streaming front end electronics: NSA Scale
ADCADCADCADCADCADCADCADC
FPGA
Continuous readout80k ch, 40 MSps @ 12 bit =⇒ 4.8 Terabyte/s∼ 80 M ch, 40 KSps=⇒Listening to every German citizen in CD quality.Zero suppression: 250 Gigabyte/s
21
Streaming back end electronics
Transport data from FEE to CPU farmSolve transposition problem (”Event building”)
Data aggregated per channelMust be processed by time slice
Common problem at intensity frontier
Solve once and reuseOpen design
wire protocolhardware
Use standard hardware
cheapereasier to extend
22
Streaming back end electronics
Transport data from FEE to CPU farmSolve transposition problem (”Event building”)
Data aggregated per channelMust be processed by time slice
Common problem at intensity frontier
Solve once and reuseOpen design
wire protocolhardware
Use standard hardware
cheapereasier to extend
23
Phase 1
Beryllium −→ Aluminum pipeCylindrical MicroMegas −→ planar GEMsOnly one proton detector ladderOnly partial streaming readout
24
Phase 1 current design
proton, pT = 8 MeV
e−, pT = 20 MeV
e+, pT = 30 MeV
e−, pT = 10 MeV
Tripple coincidence to select QED background / A′
candidate events at reasonable ratesInvestigate if we can run double coincidenceRun APV in quasi-streaming mode - free runningtrigger, mutiple frames
25
Summary
Phase 1:
Proof of target conceptSM processes: Møller, elastic scatteringDM search mock upPrototyping of streaming readoutWill run 2016
Phase 2:
Full acceptance with full streaming readoutVisible and invisible search
Low energy, intense beam physics
Intense Electron Beams WorkshopCornell University, June 17-19, 2015
http://www.classe.cornell.edu/NewsAndEvents/IEBWorkshop
26
Backup slides
27
Current status: Hardware
Xilinx Virtex-7 development board: VC 707XC7VX485T-2FFG1761Gigabit Ethernet + SFP/SFP+FMC connectors
TI ADS5295 evaluation module + adapter board8 channels80 MSPS / 12 bit
Signed up for Xilinxuniversity program
XUP donatedhardware &software
28
Current status: Hardware
Xilinx Virtex-7 development board: VC 707XC7VX485T-2FFG1761Gigabit Ethernet + SFP/SFP+FMC connectors
TI ADS5295 evaluation module + adapter board8 channels80 MSPS / 12 bit
Signed up for Xilinxuniversity program
XUP donatedhardware &software
29
Current status: Hardware
Xilinx Virtex-7 development board: VC 707
XC7VX485T-2FFG1761Gigabit Ethernet + SFP/SFP+FMC connectors
TI ADS5295 evaluation module + adapter board
8 channels80 MSPS / 12 bit
Signed up for Xilinxuniversity program
XUP donatedhardware &software
30
Current status: FPGA firmware
Milestones:SetupEthernet send/receive
OSI layer 2
Readout of ADC:
Full data of 1 ch.8 ch. with zerosuppression
Planned:
Partial streamingreadout for DL phase 1Full streaming readoutfor DL phase 2
31
Current status: FPGA firmware
Milestones:SetupEthernet send/receive
OSI layer 2
Readout of ADC:
Full data of 1 ch.8 ch. with zerosuppression
Planned:
Partial streamingreadout for DL phase 1Full streaming readoutfor DL phase 2
32
Current status: FPGA firmware
Milestones:SetupEthernet send/receive
OSI layer 2
Readout of ADC:
Full data of 1 ch.8 ch. with zerosuppression
Planned:
Partial streamingreadout for DL phase 1Full streaming readoutfor DL phase 2
33