1. Future high energy extensions of IceCube with new technologies: Radio and/or acoustical detectors
Karle

2. Acceptance at highest energies
Neutrino fluxes at highest energies > 1019 eV
require very large detection volume.
Alternate techniques to optical detection of Cherenkov light:
Radio and acoustics.
Radio:
Coherent Cherenkov emission at radio Wavelength,
Signal strength prop. E2
Askaryan, 1960’es
Targets: Salt (Salsa), Ice (Rice, Forte, Anita), Moon (Glue),…
Acoustic: Thermal energy deposition generates sound wave.
Horizontal airshowers
Note:
Optical Cherenkov detectors do operate and can reconstruct events at energies > 1018 eV.
Saltzberg, astro/ph
Line indicates slope of aperture  E

3. Diffuse Fluxes AMANDA non-contained AMANDA-II 4 yr. (not released)
IceCube, 1 yr sens.

4. Scenario for IceCube extension
optical-radio-acoustic detector
IceCube Collaboration, ICRC2005
instrumented volume :
~(110 +3) km3
Optical: 80 IceCube + 13 IceCube-Plus strings at a 1 km radius, km depth
Radio/Acoustic:
91 holes, 1 km spacing, 1.5 km depth 5 radio* acoustic receivers per hole
*probably propose more
Radio antennas

5. EFFECTIVE DETECTOR VOLUMES
Results for hybrid detector simulation (10000 events for each energy)
I: IceCube only O: Optical only R: Radio only A: Acoustic only OR: Optical and radio OA: Optical and acoustic RA: Radio and acoustic ORA: All
Typical event rates for GZK:
IceCube o(1)
Radio, acoustical extension: o(10+)
(5 antennas, 300 microphones/string)
IceCube Collaboration, ICRC2005

6. Acoustic detection R & D: World wide activities.
Ice expected to be significantly quieter (no waves, ships, dolphins etc.)
Initial Goal: determine acoustic properties of ice
Absorption length
Noise levels
Three test strings ready for deployment in 05/06 season. Deployment was not approved by NSF for logistics support reasons.
Hope/expect this year deployment.

7. Three holes with
7 acoustic stages
sensors
transmitters
up to 400 m depth
1 Acoustic Surface Box
PC/104 CPU
Power supply
DSL network
One Master-PC
GPS Time code

8. Acoustic sensors completed last fall

9. Radio
Radio technology pursued at many levels in the science community.
Examples: RICE, ANITA, LOFAR/LOPES, FORTE, Radio detection from moon, SALSA,…..
RICE-I takes data at the South Pole and produced limits.
Next level: Advance detector technology, power and communications platform, suppression of backgrounds.

10. DOM --> DRM Use a DOMMB as communication and power platform.
Advantage: get a free design for power, comms and timestamping.
In future reformat/redesign the board and reduce to the functionality needed.
Design a radio signal digitizer board which is operated through the flasherboard interface from the DOMMB
Radio digitizer is decoupled from DOMMB technology. We don’t use the frontend ofn the DOM (no ATWD, no delay board, etc.)

11. Possible deployment 06/07
9 clusters of 4 antennas distributed over 3 or more strings.
A cluster uses standard IceCube sphere, DOM mainboard and surface cable lines.
Keep completely separate in the counting house (2 computers)
Depth TBD.

12. Possible block diagram for intermediate scale readout
Antennas
Local coincidence
triggering

13. Interfaces Possible interfaces to IceCube are reviewed by the project.
Examples:
Mechanical integration in the same drill hole
Possible use of free wires
Make sure there is no detrimental effect by interference or power issues

14. Issues, questions, concerns
What is the long term strategy?
First steps first. R&D to and detector development use for intermediate scale detector. Detect a few GZK events. In the mean time develop design for large scale detector.
Does this conflict with drilling and IceCube string installation.
Not significantly. This is an important question that will not be ignored. Priorities are clear.
Future detector design still very open.
A lot more detailed simulations are needed for geometry. This includes depth (height) and spacing.
Power, communication, frontend electronics and antenna design - all part of the R&D activity needed to build an intermediate detector and design a very large detector.
Organizational matters: How do this efforts relate to
a) Project IceCube,
b) the IceCube collaboration?
Not seen as a problem, but will need some thoughts and formality as activities grow.

15. Future
Need to start now to be ready to prepare a proposal for an extension after IceCube construction is completed.

16. First bounds on n fluxes from radio !!!