exo gas progress and plans october, 2008 david sinclair
TRANSCRIPT
![Page 1: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/1.jpg)
EXO Gas
Progress and Plans
October, 2008
David Sinclair
![Page 2: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/2.jpg)
EXO Collaboration
Canada Carleton, Laurentian
USA Alabama, Caltech, Colorado State, UC irvine, Maryland, Massachusetts, SLAC, Stanford
Switzerland Bern
Russia ITEP
![Page 3: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/3.jpg)
EXO People
![Page 4: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/4.jpg)
Canadian Team
Laurentian Jacques Farine, Doug Hallman, Ubi Wichoski
Carleton Madhu Dixit, Kevin Graham, Cliff Hargrove, David
Sinclair Christina Hagemann (RA Arrives 2 weeks) Etienne Rollin (PhD Student) Chad Greene, James Lacey (MSc students)
Currently 3 undergraduate thesis/project students
![Page 5: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/5.jpg)
New effort for the gas phase
NSF grants to Stanford and Alabama for RA,s students to work on gas EXO
New EXO collaborators at ITEP who have just completed a Xe TPC project
Possible collaboration with Spanish group
![Page 6: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/6.jpg)
Heidelberg-Moscow Results for Ge double beta decay
57 kg years of 76Ge data Apply single site criterion
![Page 7: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/7.jpg)
We need to develop new strategies to eliminate backgrounds to probe the allowed space
Barium tagging may offer a way forward
![Page 8: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/8.jpg)
EXO – Enriched Xenon Observatory Look for neutrino-less double beta decay in Xe 136Xe --- 136Ba + e- + e-
Attempt to detect ionization and the Ba daughter Ba is produced as ++ ion Ba+ has 1 electron outside Xe closed shell so has
simple ‘hydrogenic’ states Ba++ can (?) be converted to Ba+ with suitable
additive
![Page 9: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/9.jpg)
Advantages of Xe
Like most noble gases/liquids it can be made extremely pure
No long lived radioactive isotopes High Q value gives favourable rates Readily made into a detector Possible barium tagging to eliminate
backgrounds
![Page 10: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/10.jpg)
Liquid or Gas
Liquid
Compact detectorNo pressure vesselSmall shield -> lower purity reqd.
Gas
Energy resolutionTracking & multi-site rejectionIn-situ Ba tagging
Large CryostatPoorer energy, tracking resolutionEx-situ Ba tagging
Large detector
Needs very large shield
Pressure vessel is massive
![Page 11: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/11.jpg)
EXO 200
A 200 kg liquid xenon detector is nearing completion at WIPP
We play a major role in this project and there is on-going activity at SNOLAB supporting this project
This talk will focus on the gas counter as this is a potential candidate for a SNOLAB project
![Page 12: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/12.jpg)
Xe offers a qualitatively new tool against background:Xe offers a qualitatively new tool against background:136136Xe Xe 136136BaBa++++ e e-- e e- - final state can be identified final state can be identified using optical spectroscopy using optical spectroscopy (M.Moe PRC44 (1991) 931)(M.Moe PRC44 (1991) 931)
BaBa++ system best studied system best studied(Neuhauser, Hohenstatt,(Neuhauser, Hohenstatt,Toshek, Dehmelt 1980)Toshek, Dehmelt 1980)Very specific signatureVery specific signature
““shelving”shelving”Single ions can be detectedSingle ions can be detectedfrom a photon rate of 10from a photon rate of 1077/s/s
•Important additionalImportant additional constraintconstraint•Huge backgroundHuge background reductionreduction
22PP1/21/2
44DD3/23/2
22SS1/21/2
493nm493nm
650nm650nm
metastable 80smetastable 80s
![Page 13: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/13.jpg)
Anode PadsMicro-megas
WLS BarElectrode
For 200 kg, 10 bar, box is 1.5 m on a side
Possible concept for a gas double beta counter
Xe Gas
. . . . . . . .
. . . . . . . .PMT
Lasers
Grids
![Page 14: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/14.jpg)
Anode PadsMicro-megas
WLS BarElectrode
For 200 kg, 10 bar, box is 1.5 m on a side
Possible concept for a gas double beta counter
Xe GasIsobutaneTEA
. . . . . . . .
. . . . . . . .PMT
Lasers
Grids
![Page 15: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/15.jpg)
Program as stated last year
Need to demonstrate good energy resolution (<1% to completely exclude ) tracking,
Need to demonstrate Ba tagging Deal with pressure broadening Ba ion lifetime Ba++ -> Ba+ conversion Can we cope with background of scattered light
![Page 16: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/16.jpg)
Tasks to design gas EXO
1) Gas Choice Measure Energy resolution for chosen gas (Should be almost as good as Ge but this has
never been achieved) Measure gain for chosen gas Measure electron attachment for chosen gas Understand optical properties Measure Ba++ -> Ba+ conversion Measure Ba+ lifetime
![Page 17: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/17.jpg)
Tasks to design EXO Gas
2) TPC Design What pressure to use What anode geometry to use What chamber geometry to use What gain mechanism to use Develop MC for the detector Design electronics/DAQ
![Page 18: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/18.jpg)
Tasks to design EXO Gas
3) Ba Tagging Demonstrate single ion counting Understand pressure broadening/shift Understand backgrounds Fix concept
![Page 19: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/19.jpg)
Tasks to design EXO Gas
4) Overall Detector concept Fix shielding requirements and concepts Design pressure containment Fix overall layout
![Page 20: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/20.jpg)
Gas Properties
Possible gas – Xe + iso-butane + TEA Iso-butane to keep electrons cold, stabilize
micromegas/GEM TEA
Converts Ba++ -> Ba+ Q for TEA + Ba++->TEA+ + Ba+* ~ 0
Converts 172 nm -> 280 nm? ? Does it trap electrons? ?Does it trap Ba+?
![Page 21: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/21.jpg)
Progress This Year
![Page 22: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/22.jpg)
AnodeGrid
Field Rings
Source
Movable source holderContacts rings with wiper
Gridded Ion Chamber
![Page 23: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/23.jpg)
Progress on energy resolution – Pure Xe, 2 Bar
Xe Energy Spectrum 3cm 2b 5992
0
50
100
150
200
500 510 520 530 540 550 560 570 580 590 600
Energy (MeV)
Co
un
ts
Alpha spectrum at 2 b pressure.
= 0.6%
![Page 24: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/24.jpg)
Program with Gridded Ion Chamber Response for many gas mixtures measured New data on drift velocities in Xe + Methane,
isobutane, TEA Some electron attachment measured but may
be due to gas impurities
![Page 25: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/25.jpg)
First efforts with Micromegas Grid and anode of chamber replaced by
micromegas Collaboration with Saclay and CERN to
produce micromegas Using new ‘microbulk’ form of micromegas as
this is thought to offer best resolution Ion density with alphas too high for this
technology – resolution ~ 1.7% Switch to betas
![Page 26: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/26.jpg)
Spectroscopy with micromegas
109Cd source
22 keV
![Page 27: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/27.jpg)
Status of Micromegas
Energy resolution of 4% observed for 22 keV x-ray is promising (-> 0.4% at 2 MeV)
Microbulk technology is not sufficiently robust for this application
Xe requires high fields for gas gain and lifetime of the micromegas is hours for these fields
Will attempt again with the T2K style micromegas
![Page 28: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/28.jpg)
Progress on Detector Simulations Double beta events being simulated in Xe
gas using GEANT and EGS Tracks are ugly!
![Page 29: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/29.jpg)
Containment of tracks
![Page 30: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/30.jpg)
Case for mixed gas
There is incentive from previous slides to investigate a mixed gas (Ne-Xe or He-Xe)
Tracks in the lighter are straighter Better containment for given amount of
(expensive) xenon
![Page 31: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/31.jpg)
Ratio of projected track to the total track length
![Page 32: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/32.jpg)
Measuring the scintillation light signal
![Page 33: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/33.jpg)
Energy and position response for scintillation light
![Page 34: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/34.jpg)
Light from gas mixtures
(this slide intentionally left blank)
![Page 35: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/35.jpg)
Measuring scintillation light in Xe gas mixtures It appears that any quench gas in Xe kills the
scintillation light It appears that the mechanism is not
absorption of the photons but interaction between Xe dimers and the additives which de-excite the dimers.
![Page 36: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/36.jpg)
Barium tagging
22PP1/21/2
44DD3/23/2
22SS1/21/2
493nm493nm
650nm650nm
metastable 80smetastable 80s
Original conceptPulse 493 nm laser toExcite D stateThen pulse 650 nm Laser to un-shelf Dstate
Does not work!
![Page 37: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/37.jpg)
New Concept for Laser Tagging in High Pressure The D state is quenched by gas interactions
in ns So – use only blue laser, look for red light
![Page 38: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/38.jpg)
Barium fluorescence Observed
![Page 39: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/39.jpg)
Status of tagging
A number of linewidth measurements made with the arc source
Changing from an arc source to a laser ablation source
We have demonstrated production of about 105 ions/pulse using an old N2 laser
We are about to modify chamber to introduce this source
![Page 40: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/40.jpg)
New Detector Concept
We have some as yet unresolved issues with the original concept
We do not get scintillation light with quenchers but we cannot have gas gain without
We are concerned that additives such as TEA will give us gas purification difficulties so how do we convert Ba++ to Ba+ and we do not know that TEA like additives will not form molecules or clusters with the Ba ions
![Page 41: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/41.jpg)
New Concept
Identify the barium production by extracting the ion into vacuum and using conventional techniques to identify a mass 136, ++ ion.
Expect this to be unique to Ba Operate the detector in pure noble gas (Xe or
Xe+Ne) Use electroluminescence in place of gas
electron gain
![Page 42: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/42.jpg)
![Page 43: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/43.jpg)
Concept for an electroluminescence readout
Design copied from Fermilab RICH counter
![Page 44: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/44.jpg)
Electroluminescence Demonstration EL is a well studied technique in noble gases and
mixed noble gases EL is preferred over electron proportional counters
for gamma ray detectors In Ne + Xe all of the light comes out at the Xe
scintillation wavelength (175 nm) for admixtures of >1% Xe
No-one has demonstrated energy resolution in MeV range
We propose to construct a detector to establish performance of EL for this application
![Page 45: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/45.jpg)
We plan a 20 x 20 array of 2 cm pads on each end
![Page 46: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/46.jpg)
Barium Identification
Because of the complexity of the electron tracks in Ba, it will be hard to determine exactly where the Ba is produced.
We have some volume within which it will be contained.
Transport that ‘volume’ to the edge of the detector
Stretch and squeeze it using field gradient into a long pipe
![Page 47: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/47.jpg)
Barium Identification (Cont)
At end of pipe have an orifice leading to evacuated region
Trap ions as they leave the gas using a Sextupole Ion Trap (SPIG)
Once the ion is in vacuum, use conventional techniques to identify it (eg Wein filter + quadrupole MS or TOF + rigidity or ….
![Page 48: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/48.jpg)
![Page 49: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/49.jpg)
Critical Design Point
What is the efficiency for getting the ion out of the pipe and trapped by the spig?
We will start by simulations for the trap varying trap geometry, pressures, gas mix
Possibly do tests on existing traps Look at improving delivery of ions down pipe
using RF carpets or FAIMS
![Page 50: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/50.jpg)
RF Carpets RF Funnels
![Page 51: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/51.jpg)
Riken Ion Source
Gas cell length is 1 m
Gas is He at 100 torr
RF is 150 V at 10 MHz
![Page 52: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/52.jpg)
RF Carpet operating at low pressure (10’s of mb)
MSU Source
![Page 53: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/53.jpg)
Ion path near the orifice
![Page 54: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/54.jpg)
Problems with RF carpets
These devices work best with low pressure, light gases
We need to work with at least a substantial fraction of Xe and we would like to work at or above atmospheric pressure
![Page 55: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/55.jpg)
FAIMS for EXO
Field Asymmetric Ion Mass Spectrometer
![Page 56: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/56.jpg)
Concept
![Page 57: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/57.jpg)
FAIMS Operation
Deflection during 1 cycle = E D (hi - lo) Let (E) = 0 + E Then = E2 D / 2 Correction field Ec = E2 D / 2 [ o 3 D ] Ec = E2 / 6 o
![Page 58: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/58.jpg)
Selecting ions based on
![Page 59: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/59.jpg)
FAIMS in non uniform field
For a non-uniform E field Say E = Eo (1 + y) Then there is a restoring field Ec = Eo
2 () y
![Page 60: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/60.jpg)
Coaxial cylinders ion selection
![Page 61: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/61.jpg)
Mass Spec on Hydrolyzed Yeast
![Page 62: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/62.jpg)
Is FAIMS useful for EXO
Would explore a different geometry with focusing to center of pipe
Need data on mobility of Ba++ in Xe, (Ne) The technique is used at atmospheric
pressure and tested to 2 bar Need to explore impact of longitudinal drift
field
![Page 63: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/63.jpg)
Only data found to date in doubly charged ion mobility
Mobilities for Xe+, Xe++ in Ne
012345678
0 50 100 150
E/N
Mo
bili
tie
s
Xe+
Xe++
![Page 64: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/64.jpg)
Where Might This Lead
We are aiming at a detector design at 200 kg scale
Would be world’s first ‘background free’ double beta decay experiment – competitive with the best in the world for sensitivity
Would be a test of concept for a ton scale detector
![Page 65: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/65.jpg)
Requirements for the Detector Needs to be deep underground to avoid
cosmogenic production of radioactive Cs Needs to be well shielded to cut the 2.614
MeV gamma background (136Xe Q value is at the Compton edge for 2.614 MeV gammas) – Water shield
Size depends on the pressure and gas mix Would likely occupy much of Cryopit
![Page 66: EXO Gas Progress and Plans October, 2008 David Sinclair](https://reader033.vdocument.in/reader033/viewer/2022051516/56649e3f5503460f94b2f7bc/html5/thumbnails/66.jpg)
What do we want from EAC
Overwhelming endorsement for the ongoing R&D program
Continued SNOLAB support Part time technician to operate and maintain the
lasers Engineering support
Note that a request for a large detector underground is likely next year – candidate for the Cryopit