A.K. DRUKIER

TEL: [ 703 225 8654 ] adrukier@gmail.com

August 2014

Nano-Booms => Dark Matter => Neutrino Geology

What we need

New class of detectors for neutral particles:Neutrons, Neutrinos, Dark Matter candidates (WIMPs)

Neutrons => Homeland Security, Neutron Microscopy

Neutrinos => Fermi Lab, Neutrino Geology

Dark Matter => Low mass WIMPS ( < 10 GeV/c2). Very high Mass WIMPs ( > 400 GeV/c2)

Spin dependent interactions (Li, F, Al) New SIGNATURES

AKD/LS, SG/ EW, AKD/DF/DS, F.T. Avignone et al.

Classical (NaI) detectors (!!! DAMA!!!)Good news: high mass, low A, annual modulation

Bad news: high threshold

Ultra-pure Ge-detectorsGood news: best backgroundBad news: low mass,

mediocre threshold (improved in CoGeNT)

Cryogenic bolometersGood news: works, good threshold for heatBad news: background? bad threshold for ionization

Liquid XeGood News: Great Mass, High A

Bad news: Mediocre S1 threshold => MDM

> 12.5 GeV/c2

“25 Years Later”

Signatures

l 1) N2 dependence on cross-section;

2) Range of recoiling nuclei is below 100 nm;

3) Particular ratio of FM = (TED/ETE) TED = Total energy deposited;

ETE = Energy transferred to electrons;

4) Annual modulation effect (AME) , Diurnal Modulation Effect (DME), Other directional effects.

Four detectors seems to see WIMPs, but

MWIMP

< O(10 GeV/c2)

Due to Kinematics Exclusions are :

• Liquid Xe only for MWIMP

> 15 GeV/c2

• CDMS-Ge only for MWIMP

> 10 GeV/c2.

• S1 in L. Xe small => Eth (S1) = O(10 keV)

Ionization in Ge low => Eth(ionization)= O(5 keV)

“25 Years Later”

DAMA, CoGeNT, CDMS-Si, CRESST, CDMS-Ge, L.Xe

AGREE, only if

• MODEL 1 => 4.1 < MWIMP

< 6.8 GeV/c2

• MODEL 2 => 3.6 < MWIMP

< 5.8 GeV/c2.

This may suggest Assymetric DM a la S. Nussinov, 1985

“25 Years Later”

The “normal “ presentation

• KINETICS

• The maximum mass transferred by a WIMP to nucleus depends on• WIMPs speed (v), nucleus mass (M

n) and WIMP mass (M

DM) by

• Emax

= 2m2v2/Mn

• wherein reduced mass m is

• m = Mn x M

DM/(M

n + M

DM)

• MDM

>> Mn => E

max => 2 M

nV2, i.e. independent of the M

DM. and

• optimal fit Mn = M

DM => E

max => ½ M

DMV

2

Challenges

1) For MDM

< 10 GeV/c2

No good detectors exist

2) For 10 < MDM

< 20 GeV/c2

Contradictory results => Low S/B

3) For 20 < MDM

< 300 GeV/c2

CDMS-Ge, LUX and Xenon negative

4) For MDM

> 300 GeV/c2

Need 10 ton , A > 70, AME

ZOO of DETECTORS – Part I

Ordered by minimal velocity at MW = 10 GeV/c2

(1) F-thermites (2) Nano-explosives

(3) O-thermites (4) Be-ssDNA

(5) Enzymatic (6) Be-SSC

(7) PICASSO (8) DAMA

(9) CoGeNT (10) CDMS-Si

(11) CRESST (12) CDMS-Ge

(13) SIMPLE (14) L. Xenon

(15) COUP

ZOO of DETECTORS – Part II

Ordered by Atomic Number

A(Be) =3- 9 Thermites, Be-ssDNA , Be-SSC

A(N) = 14 Nano-Booms

A(O) = 16 Enzymatic, CRESST

A(F) = 19 F-thermites, PICASSO, SIMPLE, COUP

A(Na) = 23 DAMA

A(Si) = 28 CDMS-Si

A(Ge) = 73 CoGeNT, CDMS-Ge

A(Xe) = 128 l. Xenon

A( I) = 131 DAMA

A(W) = 173-200 Au-ssDNA, Nano-booms, CRESST

ZOO of DETECTORS – Part III

Ordered by Eth

Eth < 0.5 keV Thermites, Nano-explosives,

0.5 < Eth < 1 keV Be-ssDNA, Enzymatic, Be-SSC

2.0 < Eth < 3 keV CoGeNT, PICASSO

Eth = O(3.5 keV) DAMA

Eth = O(5.0 keV) CDMS (Si and Ge)

Eth = O(6.5 keV) l. Xenon

Eth = O(7.0 keV) CRESST

Eth = O(15 keV) COUP

Three Models of DM Halo

“ - CRESST- OLD

Vcritical

of Existing and “Gedanken” Detectors -II

Vcritical

for New\Old Detectors

Vcritical

for New/Old Detectors

Figure of Merit for New/Old Detectors

Annual Modulation Effect

Precision WIMPology I

Low Mass WIMP’s Detection Challenge

Kinematics requires low mass targets ergo cross-section is very low ( smaller effect of coherent scattering) and requires large mass.

Ethreshold

must be very low ( < 0.5 keV)

=> current methods of background rejection does not work

=> best spatial resolution is must to improve S/B ratio

=> importance of directionality to detect AME and DM

NEED A NEW CLASS OF DETECTORS

I

Superheated Detectors

a) Bubble Chambers, Cloud Chambers – dx = O(1 mm)

b) Superconducting Granular detector – dx = O(10 microns)

c) Magnetic Nanotechnology detectors – dx = O(100 nm)

d) Explosive Nano-droplets detectors -- dx = O(5 nm)

One component-high explosives• Two components — Thermites

• Biological Detectors

• I) DNA-based detectors;• II) Enzymatic processes based detectors

Advantages of “New” Detectors

1. Room Temperature;2. Low Cost and potentially very high mass;

3. Low mass targets (Li, Be, B, C, N, O, F) possible;4. Very high mass targets ( A > 175) possible;

5. Very low Energy threshold ( 0.1-0.5 keV);

6. New methods of background rejection;7. Directionality.

MADE POSSIBLE BY NANOTECHNOLOGY

Properties of New Detectors

TYPE Mass Eth [keV] Directionality.

Be-SSC O(50 kg) 0.5-1.0 No

Be-ssDNA O(100 kg) 0.3-0.6 YES

Enzymatic O( 1 T) O(0.5 keV) No

Explosives O( 50 T) O(0.2 keV) No

O-Thermites O( 10 T) O(0.2 keV) YES

F-Thermites O( 50 T) O(0.1 keV) YES

I

Nano-Bolometry

Energy Losses

dE/dX = Ax Z1xZ

2 /[ (Z

1)0.666 + Z

20.666)]2

Ranges

Muons= O( m), Electrons =O( mm ), Alphas = O(50 microns), Recoil = O( 5 nm)

Specific Heat:

Cv = a(T/T

Debay)3 + bT => O(10-5 keV/nm3)

s

Energy Stored

Energy Stored ≈ Vgrain

High Explosives => 3.5-4.5 kev/(nm)3

O-Thermites => 3.0-4.0 keV/(nm)3

F-Thermites => 2.5-3.5 keV/(nm)3

Enzymatic => 1.5-2.5 keV/(nm)3

Amplification = Estored

/Edeposited

=> 100-1,000

Nano-Explosives Detectors (Nano-Booms)

Use very low mass targets – Li, Be, B, C, N, O

Large choice of compounds to select from;

Each explosives grain is “independent” bolometer;

Amplification of signal from 0.1 keV to 1 MeV possible;

dE/dx (nuclei) >> dE/dx (electrons) => excellent background rejection;

• Room temperature detectors

,F

Other Advantages

* Use modern nano-technology => nano-size droplets of explosives

* High energy content => large signal amplification => Gain 1,000/grain

* Packaging 1,000s of grains in 500 nm balls => Gain 1,000/ball

* May use modern acoustics to detect/localize nano-booms

* May use low cost IR-cameras

Used materials have reasonable Debay Temperature

TOTAL GAIN = 106

Limits on “thermodynamic description” :

• Works when number of molecules > 100, ergo R > 1 nm• Dynamic description may lead to factor 2 difference.

Properties of “nano-booms” detectors

Eth is proportional to grain volume, and R=O( 5 nm) grains can be produced efficiently;

Energy stored is O(4 keV/(nm)3), signal is changing as R 3, ergo 5 nm grains gives > 1 MeV;

Random distribution of grains in colloid does not increased transition width;

Millions of tons of nano-explosives are, alas, produced each year;

One can select parameters of detector, so-that explosion of a single nano-grain:

* does not trigger other grains;

* triggers other grains, with Ngrains

(triggered) = 100-1,000.

Characteristics of “nano-boom” detectors

Two main sub-classe: Explosives and Thermites Three levels of ignition temperature:

[Low = O( 50 oC)], normal [O ( 250 oC)], high [O(1,000 oC)]

Any combination of explosives possible; Complementary properties of explosives and thermites.

Behaviour of micro-granular explosives well understood, Nano-explosives partially understood; Propagation and damping of explosion well-understood;

Explosives are not detectors, there are transducers;

Many methods to detect the explosions can be implemented( accoustic, Optical).

Nunc Hercules contra plures:

Cryogenic Detectors < 20 scientists/year in last 20 years Explosives 10,000 scientists/year in last 50 years

Properties of Explosives Low Z explosives (mostly organics and nitrides))

PETN = C(CH2)ONO 

)4d = 1.6 g/cc T

ignition = O(250 oC)

RDX = (CH2)

3N

3(NO

2)3d= 1.65 g/cc T

ignition = O(250 oC)

TNT = C6H2CH3(NO2)3 d= 1.55 g/cc Tignition

= O(200 oC)

Medium Z explosives (mostly azides)

Nitrogen iodide N4I3H

3d= O(2 g/cc) T

ignition = 30 oC

CD-azide Cd (N3)

2d= O(1.5 g/cc) T

ignition = 30 oC

Cu-Azide Cu(N3)

2d=O(1.5 g/cc) T

ignition = 20 oC

High Z explosives (mostly Pb, also Hg fulminate and compounds of gold)

Pb-styphate C6H(NO

2)

3(OPb) d= 3.1 g/cc T

ignition = O ( 200 oC)

Pb-azide Pb(N3)

2d= 3.8 g/cc T

ignition = O(150 oC)

PbO6 PBO6 + dextrine(7%) d= 3.7 g/cc T

ignition = O(150 oC)

Simple Implementation using H2O

2

70% ( H2O

2) = 30%( Boron) is a good explosive

Implementation 1: Toperation

= -1 oC, naked B-grains

WIMP interacts with Oxygen

• => recoiling nuclei heats/melts H2O

2 ice

• => liquid H2O

2 burns Boron

Implementation 2: Toperation

= RT, coated B-grains

WIMP interacts with Boron

• => recoiling nuclei heats grain and melts plastic• => liquid H

2O

2 burns Boron

Properties of O- Thermites

Well known examples

Al2 + (Fe

2O

3) => Al

2O

3 + 2 Fe + 851.5 kJ/mole

Al2 + (WO

3) => Al

2O

3 + W + 832.0 kJ/mole

Both these reactions have Tignition

> 1,000 oC.

For good O- Thermite reaction:

Metal 1 should be very active and Metal 2 much less active. 4 Li + OsO

4 => 2Li

2O + Os => 500 kJ/mole

This reaction have T

ignition = O(40 oC) but Os is costly

Advantages of F-ThermitesWe can replace oxides by hexa –fluorides

6Li + WF6 => 6 LiF + W + energy (Li, W)6Na + WF6 => 6NaF + W + energy (Na, W)6K + WF6 => 6K + W + energy (K, W)

Energy from reaction of fuoride is 20-30% smaller than by oxides . But !!!!!!!!

Metal Fluoride Tm( oC) T

b(oC) (T

b-T

m)(oC)

V VF5

18.0 > 100 > 100Mo MoF

6 17.5 37. 19.5

W WF6

2.5 17.5 15Re ` ReF

618.8 47.6 28.8

Os OsF6

32.1 45.9 13.8Ir IrF

644.4 53. 8.6

Pt PtF6

61.3 69.14 7.8

For hexa-fluorides Tb = O(40 oC) and T

ignition = O(T

b)

Electrons can not ignite thermite

Electrons/gammas are main source of background in all current WIMPs detectors.

Per g/cm2 , the energy deposed by recoiling nuclei with charge Z1 in medium including heavy metal Z2 is proportional to Z1* Z2/ F(Z1,Z2). .

In classical detectors, active voxel is about 50 microns and range of recoiling nuclei is about below 50 nm.

Signal due to recoiling nuclei is comparable with signal from typical background electrons ;

In detector with active size of O ( 5 nm), the energy deposed by electrons is about 5,000 fold smaller. This leads to dE/dX (electrons) = O( 1 ev/nm ) => dT = 0.01 oC, which is not sufficient to ignite thermite.

The probability of ignition is P = exp(-dTignition

/0.05 oK) = exp( -100).

Thus thermal instabilities are totally negligible even if we have trillions of grains in detector.

Signal Calculation Lets calculate the signal for R= 5 nm +> V = 500 nm3. Vetex grain flips ,

and produces about 4 keV/(nm)3 x 500 = 2 MeV.

The heat escapes into a Rball

= 100 nm => n =1,000 grains, ergo there is propagation of ignition radially from vertex grain => 1,000 grains flips .

This gives energy deposition of Etotal

= 1,000 x 2 MeV = 2 GeV.

We can assume that the ignition of each grain by a recoiling energy will lead to flipping about 100-1,000 grains by thermal effects and presence of “debris” of exploding grain;

It is theoretically possible, that we can detect the direction of recoiling nuclei by the asymmetry of acoustic signal in a few pick-up loops built into “acoustic gradiometer”. This however, will require some experiments.

“Explosive diode” for low Mass WIMP`

The mixture of spherical grains is “symmetric”. Evaporated structures permits directionality

• Xx Xx• Xx Xx• Xx Xx • Xx Xx• ==>Xx Xx <== [Ga, WF

6]]

• Xx Xx• Xx Xx• Xx Xx

• X low A (F) x = high A (Ga)

• High energy transfer Low energy transfer

• Asymmetry is due to mismatch of target and WIMP mass, i.e. is kinematics dependent

Explosives/

Challenges of nan-boom Detectors

C14 will be a background – ad ovo synthesis need to use carbon from 1 mln years old petroleum;

Need to well control” stochimetry; Control of size important but not crucial; To diminish fast neutrons / Cosmic Rays => underground Efficient “nano-explosion detection” (acustic, optical) must be

developed.

Backgrounds, backgrounds, backgrounds…

buta) It’s a new class of “room temperature” detectors;

b) They have the high mass and low threshold;

c) It’s “elegant”;

d) Nunc Hercules contra plures.

Acknowlegments

We acknowlege discussions with:

• F.T. Avignone, R. Bielsky, R. Fagaly, K. Freese, • C. Kurdak, A. Lopez, G. Tarle, D. Spergel.

Ad memoria

Ron Brodzinsky and Roman Juszkiewicz

1) Neutrino Geophysics vs. Neutrino Geology ; 2) Reverse beta decay => Stationary Detectors => N. Geophysics; 3) Coherent Scattering => Mobile Detectors => N. Geology:

Solar Neutrino background : pp => 1010 v /(cm2xsec), low energy

pep, Be7=> 109 v/(cm2x sec), Ev = O(1 MeV);

!!! B8 => 108 v/(cm2x sec), high energy !!!

l For average density Xi of K, Th, U => S/B = O(1)

l => too low for cold spot emission tomography

l With nano-boom detectors, directionality => S/B > 10l => even cold spot emission tomography is possible.

In reality S/B =100-500, 5 ton detector = 100 events/month