# Presentation: 661191

## Using a Plasma Lens for a Neutrino Horn 

- Stephen Kahn
- 29 September 2005

- Steve Kahn -- Plasma Lens

- 29 Sept 2005

## Plasma Lens Flux Analysis

- I have replaced the first horn of the standard BNL VLBL geant with Ady Hershcovitch’s plasma lens arrangement.
- The second horn is left in place.  The hadron hose was also used.  (It happened to be left on in my geant deck).
- The standard BNL VLBL geant with the hadron hose option was used as the control.

- Steve Kahn -- Plasma Lens

- 29 Sept 2005

## Slide 3

- Steve Kahn -- Plasma Lens

- 29 Sept 2005

## Slide 4

- Steve Kahn -- Plasma Lens

- 29 Sept 2005

## Plasma Lens Geometry

- We have ignored the placement of the conductors to bring in and out the current.
- The conductors will likely be placed at positions that can absorb pions and affect the flux calculations

- Steve Kahn -- Plasma Lens

- 29 Sept 2005

## Simple Field Description

- Lens 2 with Rout=4 cm

- Lens 1 with Rin = 1 cm and Rout = 3 cm

- Steve Kahn -- Plasma Lens

- 29 Sept 2005

## What Are Reasonable Plasma Lens Parameters? 

- The answer to this may not be known.  We are likely to need to go beyond that which has already been down.
- Than is why we need R&D.
- Parameter Choices:
- Current less than 1000 kamp.
- Not sure of what radius plasmas have been achieved.  We have assumed that r<8 cm.  Typically we have used r< 5 cm.
- We have chosen the maximum L to be 200 cm.  This may be extreme.

- Steve Kahn -- Plasma Lens

- 29 Sept 2005

## Slide 8

- Steve Kahn -- Plasma Lens

- 29 Sept 2005

## Horn

- Chosen Plasma Lens
- 250 Kamp in lens 1 ,2

- The plasma lens has ~10% more flux and is shifted to higher energy distribution

- Steve Kahn -- Plasma Lens

- 29 Sept 2005

## Is a Plasma Lens Better?

- We can configure a plasma lens system that shows 10% more flux than a horn system.  The neutrino energy distribution of the plasma lens system is slightly higher than that of the horn system.
- Would we need other reasons to pursue a plasma lens?
- Probably yes.
- Past experience has shown that a horn lifetime is finite.
- The NuMi (without beam) and Miniboone (with beam) horns have been pulsed of the order of 108.
- Since the plasma lens is not mechanically strained as a horn is can we expect more long term reliability?
- Are there issues with electrode lifetime?
- R&D is required to answer these kinds of questions.

- Steve Kahn -- Plasma Lens

- 29 Sept 2005

## Total Flux when Fixing Lens 1 Current and Varying Lens 2 Current

- L=75 cm

- Steve Kahn -- Plasma Lens

- 29 Sept 2005

## High Energy Flux (E>3 GeV) for Fixed Lens 1 Current and Varying Lens 2 Current

- L=75 cm

- Steve Kahn -- Plasma Lens

- 29 Sept 2005

## Total Flux when Both Lens are in Series (Same current)

- Steve Kahn -- Plasma Lens

- 29 Sept 2005

## Varying the Length of Lens 2for Lens 1 with 250 Kamp

- Steve Kahn -- Plasma Lens

- 29 Sept 2005

## Varying Lens 2 Length with Lens 1 Current fixed at 500 Kamp

- Steve Kahn -- Plasma Lens

- 29 Sept 2005

## Total Flux for Different Lens 2 Lengths

- Steve Kahn -- Plasma Lens

- 29 Sept 2005

## High Energy Flux for Different Lens 2 Lengths

- Steve Kahn -- Plasma Lens

- 29 Sept 2005

## Variation with the Plasma Radius

- We have chosen configurations with constant currents and varied the plasma radius.
- Upper figure uses I1=I2=250 Kamp.
- The lower figure uses I1=250 Kamp, I2=500 Kamp.
- There does not appear to be significant improvement with larger radius plasmas.

- Steve Kahn -- Plasma Lens

- 29 Sept 2005

## Conclusions

- We have found a Plasma Lens configuration that performs slightly better than the traditional horn system.
- This confirms somewhat what we have known
*A horn geometry works well.  Our horn produces an efficiency about 1/3 of the non-Liouville perfect system where every pion is directed miraculously at the detector.*
- A plasma lens with extremely large currents does not seem necessary.
- A plasma lens system maybe preferable to produce a higher energy spectrum.
- The plasma lens systems appears to favor current parameters not significantly different from the horn.

- Steve Kahn -- Plasma Lens

- 29 Sept 2005