# Presentation: 842333

## CERN Hg Jet System

**V.B. Graves**
**P.T. Spampinato**
**T.A. Gabriel**
**MUON Collaboration Meeting**
**Lawrence Berkeley National Laboratory**
**February 16, 2005**

## Outline

**Requirements / constraints**
**Original Hg delivery concept & issues**
**New baseline delivery system**
**Operations / Hg handling**
**Schedule**

## Design Requirements & Constraints

**Hg Jet**
**1cm dia, 20m/s (1.57 liter/s, 24.9 gpm) in same direction as beam**
**Free jet created inside 15cm magnet bore**
**Smooth, steady-state jet duration overlaps 1-sec max field duration**
**Integrate optical diagnostics**
**Fiber-optic system integrated with 5K frames/sec camera to record jet/beam interaction**
**40-100 beam shots over 1 week period**
**Period between beam shots approximately 30 minutes to allow magnet cooling**
**No target equipment on up-beam end of magnet**
**Materials compatibility with Hg**
**Component module size limitation is 1.3m x 3m (facility issues)**

## Experiment Geometric Configuration

**Experiment is prototypic of a N.F. facility target layout**
**Magnet tilt (wrt beam) = 66 mrad (3.8****°)**
**Hg jet tilt (wrt magnet axis) = 100 mrad (5.7°)**
**Hg jet center intersects beam center at Z=0**

## Experiment Location – TT2A Tunnel

**A. Fabich**

**Equipment**

**Control Room**

## System Overview

## Original Hg Delivery System

## Pump Issues

**Pump adds heat to Hg**
**Pump delivers nominal 51 bhp at 23% efficiency (60 bhp max)**
**Magnetic coupling losses 5.4 hp**
**Heat energy into mercury**
**LostHP = (bhp - mag)*(1 - eff) + mag = 40.5 hp (30kw)**
**With an assumed Vol=12liter, ****Δ****T=2.4°F/sec (1.3°C/sec) due to pump heating only**
**Heat exchanger might be required**
**Max available pump output pressure is 750 psi (50 bar)**
**Estimated piping system pressure drop 800-850 psi**

## Alternative Hg Delivery System

## System Energy Comparison

## New Baseline Target System

## Primary Containment

## Hg Plenum

**Purpose is to provide reservoir to allow Hg to change direction in confined space**
**Several designs have been considered**
**Open chamber with nozzle exit and beam thru-tube**

**Beam**
**Window**

## Primary Containment – Side View

## Primary Containment Cross Section

## Optical Diagnostics

- test target

- Retro-reflected illumination

- Spherical mirror

- laser
-  illumination

- image
-  collection

- cm scale

- T.Tsang, BNL

## Optical Diagnostics

- optical design in secondary containment

- One set of optics
- per viewport

- e-Drawing - Van Graves, ORNL

- e-Drawing - Van Graves, ORNL

- T.Tsang, BNL

## Secondary Containment

**SS sheet metal enclosure around entire primary system**
**Contains Hg leaks, provides access to monitor Hg vapors**
**Provides access to optical diagnostics, hydraulics, and sensors**
**Incorporates beam windows**
**3 components: hydraulics box, target cover, connecting rubber sleeve**

## New Baseline Hg Target System

**Secondary tank dimensions 102x36x45" (2.6x0.9x1.1m) without support base**
**Need to reduce footprint**
**Facility limits are 3m x 1.3m**

## Syringe Layout

## Title 1 Design Review Comments

**Nozzle design**
**More analysis needed**
**Nozzle/deflector designs need validation**
**Replaceable or adjustable nozzle**
**Viewports**
**Structural rigidity of viewport optics**
**May require testing**
**System sizing**
**Footprint for 20sec syringe too large**
**Increase cylinder diameter (from 8" to 12") to decrease required stroke**
**Add filtered breather system to primary containment**
**Clarify CERN facility requirements**
**Operational logistics affect system design**
**Prepare failure analysis**

## Hg Cylinder Upsizing

**Original: 8” Hg cylinder**
**Updated: 12” Hg cylinder**
**Both with 20sec capacity**

- ~1m

- ~3.5m

## Hg Handling Issues

_**Properties, Safety Limits, Standards**_
**Atomic Weight: 200.59**
**Boiling Point: 357 degree C**
**Specific Gravity: 13.6**
**Vapor Pressure: 0.0012 mm Hg**
**Vapors: colorless, odorless**
**Solubility: insoluble in water**
**NIOSH/OSHA limits: 0.05 mg/m****3****, 10 h/day; 40 h/wk**
***ORNL: 0.025 mg/m******3******, respirators at 0.012 mg/m******3***

## The Target Test Facility (TTF) - Basis For ORNL’s Hg Handling Experience

**Full scale, prototype of SNS Hg flow loop**
**1400 liters of Hg**
**Used to determine flow characteristics**
**Develop hands on operating experience**
**Assess key remote handling design issues**

## TTF Pump Room and Target Room

**75 Hp centrifugal pump**
**Nominal flow at 1450 liters/min (380 gpm)**
**Completed several major equipment upgrades for piping and target configuration**

## Hg Transfer

**TTF vacuum pump was used to transfer Hg directly into the storage tank**
**Lower risk than manual loading or using a pump**
**Faster operation, ~ 1-1/2 minutes per flask (over 500 flasks required for TTF)**

## Proper PPE Is Mandatory

**Overalls, gloves, and overshoes are the minimum requirement, respirators used if indicated by Hg vapor monitoring**

## Mercury Puddling

**Mercury will collect into small droplets and large puddles even in pipes sloped at 1 degree**

## Mercury Monitoring

**TTF Uses Three Stationary Jerome 431-X Vapor Analyzers**
**One monitor dedicated to each room and exhaust vent, connected to the Target Test Facility PLC**
**A portable monitor used during loop maintenance activities **
**The Jerome analyzer has a range of 0.000 – 0.999 mg/m****3**
**Sensitivity is 0.003 mg/m****3**
**Measures the change in resistance across a gold film as a function of Hg vapor**
**Other monitor types are available**

## Equipment Decommissioning/Disposal

**The target equipment (and the solenoid) will have neutron-induced activation**
**Based on (H. Kirk 9/01/04)**
**200 pulses**
**16 x 10****12**** protons/pulse (avg.)**
**30 days of operation**
**Contact dose rate on the iron exterior will be:**
**after 1 hr        40 mrad/hr**
**after 1 day     21 mrad/hr**
**after 1 week  13 mrad/hr**
**after 1 mo.      5 mrad/hr**
**after 1 year     1 mrad/hr**
**ORNL will take back the Hg target system and dispose of activated Hg and components**
**Magnet, power supply, and cryosystem should be available for other uses ... may be sent to KEK**

## Hg Target Schedule Highlights

| Title 1 Design Review at ORNL | Feb 7-8, 2005 |
| --- | --- |
| Collaboration Mtg at CERN | Mar 15-17, 2005 |
| Title 2 Design Review | May-June '05 |
| Target System Procurement & Fabrication (dependent on funding) | July '05 – Oct '05 |
| Assembly & Testing at ORNL | Nov '05 – Jan '06 |
| Integrated Testing w/Magnet | Feb '06 – Apr '06 |
| Equip. Installation at CERN | Oct '06 – Nov '06 |
| Earliest Beam-on Tests at CERN (no beam time scheduled yet) | Dec '06 |