PICO 250-liter Bubble Chamber Dark Matter Experiment Michael B. Crisler Fermi National Accelerator Laboratory
21 August 2013 M.B. Crisler SNOLAB Future Projects Workshop 1 PICO Collaboration
C. Amole, M. Besnier, G. Caria, A. Kamaha, A. Noble, T. Xie
M. Ardid, M. Bou-Cabo
D. Asner, J. Hall
D. Baxter, C.E. Dahl, M. Jin
E. Behnke, H. Borsodi, C. Harnish, O. Harris, C. Holdeman, I. Levine, E. Mann, J. Wells
P. Bhattacharjee, M. Das, S.J. Brice, D. Broemmelsiek, J.I. Collar, R. Neilson, S. Seth P.S. Cooper, M. Crisler, A.E. Robinson W.H. Lippincott, E. Ramberg, F. Debris, M. Fines-Neuschild, C.M. Jackson, M.K. Ruschman, M. Lafrenière, M. Laurin, L. Lessard, A. Sonnenschein J.-P. Martin, M.-C. Piro, A. Plante, O. Scallon, N. Dhungana, J. Farine, N. Starinski, V. Zacek R. Podviyanuk, U. Wichoski
R. Filgas, S. Gagnebin, C. Krauss, S. Pospisil, I. Stekl D. Marlisov, P. Mitra I. Lawson, E. Vázquez Jáuregui D. Maurya, S. Priya PICASSO + COUPP = PICO New collaboration is PICO PICASSO
Ongoing efforts with Superheated Droplet Detectors
Committed to Geyser Chamber R&D through FY13 COUPP
Ongoing efforts with COUPP-60 bubble chamber Committed to Fast-Compression Bubble Chamber R&D through FY13
M.B. Crisler SNOLAB Future Projects 21 August 2013 Workshop 3 PICASSO + COUPP = PICO PICASSO focus on spin-dependent couplings
Fluorine based fluids – C4F10 COUPP
focus on simultaneous SI & SD couplings
Fluorine and iodine - CF3I First Collaborative PICO Effort = PICO-2L:
2-liter C3F8 chamber at former COUPP-2L site Spin-dependent couplings + low mass SI
M.B. Crisler SNOLAB Future Projects 21 August 2013 Workshop 4 The Bubble Chamber Propylene Glycol fast compression Spin-indep (hydraulic fluid)
Superheated CF3I target Spin-dep* Spin-dep C F –C F 3 8 4 10 Water Particle interactions (buffer) nucleate bubbles
Cameras capture bubbles
(target Data Logged, Chamber fluid) compressed after each event * This doesn’t work so well… M.B. Crisler SNOLAB Future Projects 21 August 2013 Workshop 5 The Geyser Chamber hydraulic fluid Superheated target Spin-dep C3F8–C4F10 Particle interactions buffer nucleate bubbles fluid
Cameras capture bubbles
Data Logged, Chamber target compressed after each fluid event
M.B. Crisler SNOLAB Future Projects 21 August 2013 Workshop 6 The Geyser Chamber Idea:
Add a cold condenser space at the top of the chamber volume Establish thermodynamic conditions so that bubbles rise to the top, condense, and the liquid falls back into the active volume Continuous operation without dead-time Eliminates the need for fast compression
M.B. Crisler SNOLAB Future Projects 21 August 2013 Workshop 7 Dark Matter Bubble Chamber Evolution
Test tube COUPP 2kg PICO 0.01 COUPP 4kg PICO 0.1 PICO 1liter COUPP 60kg PICO 2liter
PICO’ 2liter M.B. Crisler SNOLAB Future Projects PICO 250 liter 821 August 2013 Workshop The Physics of Bubble Nucleation
Energy from particle interactions produces σ = surface tension P = liquid pressure “proto-bubbles” l Macroscopic bubbles
arise from proto-bubbles Pv = vapor pressure with radius r > rc The energy threshold Eth is the energy required to produce a critical radius bubble Bubble nucleation requires ER > Eth and Surface energy Latent heat recoil path length < Rc Seitz “Hot Spike” Model Phys.&Fluids&1,&2&(1958) M.B. Crisler SNOLAB Future Projects 21 August 2013 Workshop 9 The Physics of Bubble Nucleation
Tune Temperature T and Pressure P for set nuclear recoil threshold.
No sensitivity to electron recoils
M.B. Crisler SNOLAB Future Projects 21 August 2013 Workshop 10 The Bubble Chamber is a Threshold Device
α-recoil
We do not measure ER… dark matter
ER …we measure dN dER dER
Eth
Eth …so bubbles initiated by recoiling α-decay daughters are counted along with dark matter candidate events.
M.B. Crisler SNOLAB Future Projects 21 August 2013 Workshop 11 The Physics of Bubble Growth PICASSO (Aubin et al., arXiv:0807.1536) Sound emission from a bubble peaks at rbubble ~ 10 um Clear acoustic signature for a single nuclear recoil α-decay results in separate nucleation sites ~ 40 µm α-decays are significantly louder Observable)bubble)~1)mm)
~40)μm)
~50)nm)
Daughter)heavy)nucleus) Helium)nucleus) (∼100)keV)) (∼5)MeV))
M.B. Crisler SNOLAB Future Projects 21 August 2013 Workshop 12 Acoustic Parameter
(Amp • ω)2 (Normalized and position-corrected for each freq-bin)
Measure of acoustic energy deposited in chamber
Alphas are louder than neutrons
M.B. Crisler SNOLAB Future Projects 21 August 2013 Workshop 13 The Bubble Chamber
fused silica inner vessel Flexible pressure balancing bellows Instrumented with Temperature, Pressure Transducers Fast Transient Pressure Transducer Piezo Electric Acoustic Transducers Immersed in hydraulic fluid within a stainless steel pressure vessel Hydraulic pressure controls the superheated fluid pressure Viewed by machine vision cameras
M.B. Crisler SNOLAB Future Projects 21 August 2013 Workshop 14 Bubble Chamber Operation Cycle
M.B. Crisler SNOLAB Future Projects 21 August 2013 Workshop 15 The Data Trigger frame
10 frames of Stereo Camera Images
Synchronized measurements of Acoustic Traces P, T, and control parameters Pressure Growth
2.5 Mhz waveform digitizer for acoustics and fast pressure transducer.
M.B. Crisler SNOLAB Future Projects 21 August 2013 Workshop 16 Dark Matter Bubble Chambers
Insensitive* to γ and β backgrounds
Threshold device, integral distribution
Event-by-event tagging of α-recoils
Only background should be neutrons
M.B. Crisler SNOLAB Future Projects 21 August 2013 Workshop 17 Dark Matter Bubble Chambers
Insensitive* to γ and β backgrounds * There is a catch here… Our γ and β rejection is not perfect,
and the onset of gamma sensitivity limits the lowest viable operating threshold
M.B. Crisler SNOLAB Future Projects 21 August 2013 Workshop 18 Gamma Rejection Measurements
Gamma rejection in C3F8 Gamma rejection in CF3I
10-10 ~ 12 keV 10-10 ~ 3 keV
M.B. Crisler SNOLAB Future Projects 21 August 2013 Workshop 19 Dark Matter Bubble Chambers
Emin determines dark matter sensitivity For a velocity of 300 km/sec
Eiodine = 63 keV so Emin = 12 keV is OK
Efluorine = 9.5 keV so Emin = 12 keV is not OK
Good sensitivity to fluorine recoils from dark matter requires a 2-3 keV threshold attainable
only with C3F8 or C4F10
M.B. Crisler SNOLAB Future Projects 21 August 2013 Workshop 20 NEW Explicit Confirmation of a sharp Bubble
Nucleation Threshold for Iodine Recoils in CF3I Telescope trigger Acoustic signal
-0.019 -0.018 -0.017 Time (s)
Downstream pixel hits Upstream pixel hits
Y position (mm) The Seitz Model works
very well for iodine in CF3I Z position (mm) 1 cm diameter bubble chamber 12 GeV/c π- test beam M.B. Crisler SNOLAB Future Projects 21 August 2013 Workshop 21 COUPP 4kg @ SNOLAB
Excellent Rejection of Alpha Backgrounds in
CF3I α rejection >98.9% α rejection > 99.3% 15 keV data
COUPP-4 Dark Matter
Sensitivity from CF3I was limited by backgrounds Neutrons 20 WIMP Anomalous* (CF3I related) candidates
Not random in time Anomalous Background not yet understood
M.B. Crisler SNOLAB Future Projects 21 August 2013 Workshop 22 COUPP-60 at SNOLAB CF3I effort continues with COUPP-60 Operating since June 2013 >1000 kg-days Competitive for Spin-Independent
M.B. Crisler SNOLAB Future Projects 21 August 2013 Workshop 23 19 Problems with F response in CF3I
…poor fluorine recoil nucleation efficiently
NEW
M.B. Crisler SNOLAB Future Projects 21 August 2013 Workshop 24 Threshold and Efficiency: SRIM simulation* 19 12 15 keV F and C recoils in CF3I have tracks significantly longer than the critical radius for bubble formation
…so fluorine recoils do not nucleate efficiently in CF3I fluorine recoils do nucleate efficiently in C3F8 M.B. Crisler SNOLAB Future Projects 21 August 2013 Workshop 25 Gamma rejection sets the threshold. C3F8 for SD, low mass The 10-15 keV Threshold necessary for CF3I is kinematically unfavorable for 19F recoils Gamma rejection in C3F8 Gamma rejection in CF3I
10-10 ~ 12 keV
3 keV threshold Excellent Spin-dependent provides excellent 10-10 ~ 3 keV Plus Spin-Independent Low Mass sensitivity for 19F recoils
M.B. Crisler SNOLAB Future Projects 21 August 2013 Workshop 26 Dark Matter Sensitivity with C3F8 / CF3I
−36 10 ] ] 2 2 −40 DAMA 10 bb) PICASSO 2012 PICASSO 2012 COUPP 2012 CoGent χχ → ) ( − −38 + W 10 CRESST K (soft) W PICO 2L − IceCube −42 Super χ → (χ 10 COUPP 2012 −K (hard) Super PICO 250L −40 CMS (A−V) CDMS 10 PICO 2L −44 proton cross section [cm nucleon cross section [cm − 10 C
− 3 F XENON10/100 8 , 3 keV −60 PICO 250L COUPP , 3 keV F 8 −42 C 3 −46 PICO 250L SD WIMP 10 SI WIMP 10 I, 15 keV CF 3 1 2 3 4 1 2 3 10 10 10 10 10 10 10 WIMP mass [GeV/c2] WIMP mass [GeV/c2]
M.B. Crisler SNOLAB Future Projects 21 August 2013 Workshop 27 PICO-2L
Focus on SD couplings low mass SI
2-liter C3F8 target Expect 3 keV threshold Installation in progress Physics this year
M.B. Crisler SNOLAB Future Projects 21 August 2013 Workshop 28 PICO 250-liter
M.B. Crisler SNOLAB Future Projects 21 August 2013 Workshop 29 250-L Bubble Chamber Design (1) Instrumentation, DAQ, Controls Synthetic Silica Inner vessel Bellows Assembly Optics, Photography Outer Pressure Vessel Hydraulic and Thermal Components
M.B. Crisler SNOLAB Future Projects 21 August 2013 Workshop 30 250-L Bubble Chamber Design (1) Instrumentation, DAQ, Controls Synthetic Silica Inner vessel Bellows Assembly Optics, Photography Outer Pressure Vessel Hydraulic and Thermal Components
M.B. Crisler SNOLAB Future Projects 21 August 2013 Workshop 31 250-L Bubble Chamber Design (2) Shielding and Experiment Infrastructure Cleaning Infrastructure Assembly and Handling Fixtures Fluid purification Fluid handling Site Specific Engineering
M.B. Crisler SNOLAB Future Projects 21 August 2013 Workshop 32 Inner Vessel
Synthetic Silica is the only proven option 250 liters is manufacturing limit 600 mm (24”) diameter 1.3 meter overall length
Acrylic might be an option for C3F8/C4F10 Not yet demonstrated – surface nucleation?
M.B. Crisler SNOLAB Future Projects 21 August 2013 Workshop 33 Synthetic Silica Inner Vessel
A 30” (762 mm) diameter vessel would yield a roughly spherical active volume, minimize the surface area to volume ratio, and optimize the camera coverage.
But… requires 10 mm wall thickness
Three different vendors agreed, (for different reasons) that the 30” (609.6 mm) diameter vessel and the 10 mm wall thickness were beyond their technical capabilities. …but this vessel could be fabricated with acrylic or other plastic M.B. Crisler SNOLAB Future Projects 21 August 2013 Workshop 34 Synthetic Silica Inner Vessel
The largest vessel that the vendors can deliver is 250 liters But with a taller aspect ratio:
The vessel would be 24” (609.6 mm) diameter with 8 mm wall thickness
The optics are more challenging but it works. Requires 4 cameras
M.B. Crisler SNOLAB Future Projects 21 August 2013 Workshop 35 Synthetic Silica Inner Vessel FEA tells us that we need a very robust flange
M.B. Crisler SNOLAB Future Projects 21 August 2013 Workshop 36 Maximum Tensile Principal Stress
Vacuum (18 psi) Loading Hydrostatic + 6 psi overpressure
M.B. Crisler SNOLAB Future Projects 3721 August 2013 Workshop Inner Vessel - gold wire seal design
M.B. Crisler SNOLAB Future Projects 21 August 2013 Workshop 38 Inner Vessel – flange flatness specification
M.B. Crisler SNOLAB Future Projects 21 August 2013 Workshop 39 Maximum Principal Stresses in Flange-to-Shell Transition A simpler flange works, …but requires 51 mm flange thickness 2” Loading is hydrostatic plus 6 psi overpressure
ps i
Maximum allowable stress = 1000 psi
40 Synthetic Silica Inner Vessel – tapered flange option
M.B. Crisler SNOLAB Future Projects 21 August 2013 Workshop 41 Synthetic Silica Inner Vessel – thick flange option
M.B. Crisler SNOLAB Future Projects 21 August 2013 Workshop 42 Inner Vessel – status
Design complete Drawings FEA Seal design Engineering note Procurement specifications Vendor Preliminary Quotations Range from $150K to $270K
M.B. Crisler SNOLAB Future Projects 21 August 2013 Workshop 43 Inline pressure balancer 4-kg prototype
M.B. Crisler SNOLAB Future Projects 21 August 2013 Workshop 44 Inline pressure balancer
COUPP-500 design: Simple scale-up Easier design at larger diameters
Very small pressure differential ~1/2 psi
M.B. Crisler SNOLAB Future Projects 21 August 2013 Workshop 45 Inline pressure balancer -status
90% solid model Needs work on details of mounting and alignment
M.B. Crisler SNOLAB Future Projects 21 August 2013 Workshop 46 Camera Mount /Chamber Optics
Hexapod camera mount Reproducible alignment
M.B. Crisler SNOLAB Future Projects 21 August 2013 Workshop 47 Optical Model for the Chamber
Optics model determines viewport placement and orientation
Determines space requirements for retro- reflective screen
M.B. Crisler SNOLAB Future Projects 21 August 2013 Workshop 48 Solid model of the Chamber
M.B. Crisler SNOLAB Future Projects 21 August 2013 Workshop 49 M.B. Crisler SNOLAB Future Projects 21 August 2013 Workshop 50 Hydraulic Cart Architecture
AC Chassis Instrumentation Chassis 2-liter Hydraulic Cart
Isolated AC Power Entry AC Chassis DC supplies Switching Relays Instrumentation Chassis DC only +12 VDC, +24 VDC AC Power Entry
M.B. Crisler SNOLAB Future Projects 21 August 2013 Workshop 51 Hydraulic Cart Functional Diagram (simplified)
accumulators P Large Bore Hydraulic Pmax min Bubble Connection is a Point Chamber of Seismic Vulnerability
pump
Fast compression (NC)
slow compression (NO) expansion (NC) M.B. Crisler SNOLAB Future Projects 21 August 2013 Workshop 52 Hydraulic Cart Functional Diagram Moving the fast compression to the pressure vessel eliminates the most challenging piping. Fast compression (NC) accumulators Pmax Pmin
Bubble Chamber
pump
slow compression (NO) expansion (NC) M.B. Crisler SNOLAB Future Projects 21 August 2013 Workshop 53 Choice of hydraulic fluid Choices: Hydraulic Fluid serves as mineral oil Hydraulic fluid for compression propylene glycol Water Optical medium for photography glycerol Low compressibility is desirable Index of refraction is a trade-off
High index matches silica & reduces reflections Low index matches target fluid and reduces demagnification Should be environmentally acceptable
M.B. Crisler SNOLAB Future Projects 21 August 2013 Workshop 54 Pressure Vessel with integral fast compression
M.B. Crisler SNOLAB Future Projects 21 August 2013 Workshop 55 How it might look in shielding
M.B. Crisler SNOLAB Future Projects 21 August 2013 Workshop 56 Infrastructure requirements are modest:
M.B. Crisler SNOLAB Future Projects 21 August 2013 Workshop 57 Infrastructure requirements are modest:
M.B. Crisler SNOLAB Future Projects 21 August 2013 Workshop 58 Infrastructure requirements are modest:
M.B. Crisler SNOLAB Future Projects 21 August 2013 Workshop 59 COUPP-500 engineering to do: Thermal Control of large pressure vessel Baseline model is to: insulate the pressure vessel Circulate the hydraulic fluid Heat Exchanger and Pump integral to Pressure Vessel Body Mechanical handling fixtures
Fixtures for cleaning, handling, and assy of IV. Site Specific Engineering
M.B. Crisler SNOLAB Future Projects 21 August 2013 Workshop 60 Expectations for FY13
First Results from COUPP-60 (CF3I)
First Results from PICO-2L (C3F8) Complete Baseline Engineering Design of PICO-250L (the bubble chamber and its auxiliary equipment, not necessarily the site-specific infrastructure at SNOLAB.)
Complete R&D on C3F8 characterization
M.B. Crisler SNOLAB Future Projects 21 August 2013 Workshop 61 COUPP-500 Proposal
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Table 3 provides a breakdown by year and by funding agency of the anticipated cost to design and build a COUPP-500 device. The NSF numbers are identical to those requested in proposal 1242637 in April 2012 by the NSF funded COUPP institutions in response to program announcement PD 12-1643. The ‘Research’ row of the NSF block contains scientific salaries. There is no corresponding row for the DOE block as scientific salaries are not beingNominal sought in this proposal.FY14-FY15 construction
FY FY13 FY14 FY15 Total 12 DOE Design, eng. 1297 575 575 2447 & tech. supp. Equipment 425 425 850 Fabrication 850 850 1700
NSF Research 143 937 920 946 2946 R&D 600 250 850 Construction 378 623 501 1502
Table 3: A breakdown by year and by funding source of the anticipated cost of a COUPP-500 device. All numbers are in k$ and include indirect costs. The sum being requested in this proposal is the M.B. Crisler SNOLAB Future Projects $1297 DOE21 fundsAugust 2013for FY13. Workshop 62
We anticipate one year devoted mainly to the design of the experiment (FY13) and two years of construction (FY14-FY15). The costs for the first year are relatively well defined and are presented in Table 2. We regard these design activities as a prerequisite for accurate estimations of the construction cost. In the absence of design details, we have made the estimates shown in Table 3. These estimates assume significant cost sharing with the NSF for both equipment and engineering. It should be noted that the NSF Proposal has budget tables with DOE numbers that differ slightly from those in Table 3. At the time of writing the NSF proposal the DOE numbers were estimates that have undergone further refinement to produce the numbers in Table 2 and Table 3.
The COUPP-500 NSF proposal requested salary for an engineer. It is anticipated that this person would function as a Project Engineer, coordinating and overseeing the engineering and design work being requested in this DOE proposal.
Table 3 includes subtotals broken down into the categories requested in the Program Announcement, “Engineering, design and technical support”, “Fabrication”, and “Equipment” (The fourth category, “management”, is omitted, since Fermilab line management costs are included as indirect costs and we expect that project management will be performed by physicists). Since important decisions about which components of
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