Fundamental InteractionsPhysics & Instrumentation

Conclusions

Conveners:

P. Mueller, J. ClarkG. Savard, N. Scielzo

2

Short Term

Fully utilize low energy beams from CARIBU for mass measurements, laser spectroscopic studies and decay experiments. Ideally, the space available for low energy experiments at CARIBU should be expanded to fully exploit these possibilities (NA6).

3

Initial focus of measurements with the CPT at CARIBU

First measurements:

• 132Sn and neighbors

• 130Cd and neighbors

Future measurements:

• go as neutron-rich as possible

4

Moving the CPT to CARIBU

CARIBU

5

Laser Lab Layout @ CARIBU

AC

H

EP

A

Laser Enclosure(~ 6’ x 10’)

Laser Table(~ 3’ x 7’)

Ion Trap

Collinear Beamline

Tape Station

Cf-252 source80 mCi -> 1Ci

High-resolutionmass separatorm/m > 1/20000

Gas catcher

RF Cooler & Buncher

… starting in fall 2010

6

Beta-delayed neutron emission

Plastic scintillator

Plastic

scintillator

n

94Sr

95Rb+

95Rb 95Sr* 94Sr* n

• 1-mm3 trapped-ion sample and 1-ns timing resolution of detectors determines neutron momentum/energy to ~1% from time-of-flight of recoiling daughter ion

• intrinsic efficiency for MCP detectors can be ~100%

• many fission fragments available from the newly-developed CARIBU facility (an intense source of fission-fragment beams) at ANL

Novel approach: determine neutron energies and branching ratios by detecting beta particles and recoil ions that emerge from ion trapProvide reliable data for: r-process nucleosynthesis, nuclear structure, nuclear reactor performance, modeling of environments where fission fragments are produced

MCP ion detector

ExampleQ = 4.9 MeVt1/2 = 0.378 secPn ≈ 9%

7

Short Term

Utilize ATLAS intensity upgrade (Phase I) for improved beta decay correlation experiments and weak interaction studies by increased production rate of light isotopes close to stability (e.g. 6He, 8Li, 14O, 18Ne ) (FI4). Phase II upgrade, in particular the recoil separator, would significantly improve production and separation of these isotopes.

8

Beta-neutrino correlation in 8Li

DSSD Plastic scintillator

8Li+

8Li 8Be*

Neutrino momentum/energy can be determined from and recoiling 8Be momentum/energy

momentum/energy measured from DSSD and plastic scintillator detector

8Be momentum/energy determined from particle break-up… with no recoil, particles would have same energy and would be back-to-back. With recoil, energy difference can be up to 730 keV and the angle can deviate by as much as ±70

Low mass of 8Li and Q ≈ 13 MeV lead to large recoil energies of 12 keV which makes the correlation easier to measure. Other correlation measurements have had to deal with recoil energies of only 0.2-1.4 keV.

Beta-neutrino correlation measurement takes advantage of 1 mm3 trapped ion sample and position and energy resolution of double-sided silicon strip detectors to precisely reconstruct momentum vectors of all emitted particles (including neutrino!)

9

MCPDSSD+ Scint.

MOTchamber

Atomtraps

Dipole traplaser

Atomic beam

Beta-Decay Study with Laser Trapped 6He

• 6He trapping rate: 1104 s-1,

• 2105 coincidence events in 15 min: a = ± 0.008

• 1 week: a/a = 0.1%

Cou

nts

500450400350300250200150Time of Flight (ns)

a = +1/3

a = -1/3

Simulated time-of-flight signal

Standard Model

New Physics

6He yields:• ATLAS: 1107 s-1

• CENPA: ~1109 s-1

• SARAF / SPIRAL2: ~11012 s-1

10

Medium Term

Improve isotope separation and overall transmission of the ion transfer line after the gas catcher into the triangle room. This would enable mass measurements closer to the proton drip line (65As) once the CPT is moved back to its previous location (NA2). This upgrade also would improve correlation studies and decay experiments possible at that location (FI4).

11

Moving the CPT to CARIBU

CARIBU

12

Long Term

Add gas catcher and low-energy beam-line behind recoil separator for studies of very proton rich isotopes (e.g. around 100Sn, requires Phase II). Provide experimental area to accommodate low-energy beam experiments, e.g., in the ATSCAT area.

Support high precision measurements of basic nuclear properties of isotopes close to stability (on the proton rich side) to enable future high precision measurement far off stability at FRIB, e.g., measurements of T=2 superallowed beta decays.

13

Moving the CPT to CARIBU

CARIBU

RecoilSeparator

14

T=2 nuclei present an alternative way to check

Isospin breaking corrections

Bhattacharya et al., PRC 77, 065503 (2008)

15

Long Term

Find a stronger source for 225Ra for improved EDM experiment that will be truly statistics limited (FI9).

16

Search for EDM of 225Ra

Transversecooling

Oven:225Ra (+Ba)

Zeeman Slower

Opticaldipole trap

EDMprobe

Advantages:

•Large enhancement:

EDM(Ra) / EDM(Hg) ~ 200 – 2000

•Efficient use of 225Ra atoms

•High electric field (> 100 kV/cm)

•Long coherence times (~ 100 s)

•Negligible “v x E” systematic effect