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TLM detector cable

Chipmunk

Chipmunk electrometer(blue box)

Chipmunk ion chamber

Prelude

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3 parallel TLM detectors125’250’350’

PbarA2B7

magnet

TLM providescontinuous, in-tunnel

coverage

Chipmunks providediscrete, above-ground

coverage

Prelude

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The problem: Radiation Safety System (RSS) at pbar service buildings

includes 42 Chipmunks Adequate for the 8 GeV, 13 watt pbar ops

RSS needs to be extended for 8 GeV, 8 kW mu2e operation – about 200 units

Unit cost is about $10k or total of $2M Includes detector construction, doghouses, electrical

installation M&S, RSS infrastructure

Would add tremendous complexity, e.g., Chipmunks require annual calibration

RSS testing

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Why TLMs? Following a Director’s review in May 2011 for mu2e CD1,

ESH&Q Section Head suggested that we consider Long Detectors in lieu of Chipmunks

Long detectors have a long history at FNAL; they have been highly regarded by their proponents Switchyard

Booster

NuMI

External beam lines

The obstacle: long detectors could not serve in the capacity of a CREDITED CONTROL for the Accelerator Safety Envelope

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Development history Work to characterize long detector

response began immediately in May 2011

A long series of studies was conducted at pbar to characterize detector response as a function of 8 GeV beam loss

Detector response curves for the ion chamber region were developed

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Development history BLM electrometers were used in early studies

with disappointing results

A Chipmunk, sans ion chamber, was then used (aka blue box, electrometer) Provided linear, predictable response

The blue box was already a critical component of the existing RSS!

Electrometer: collects and measures charge produced in the detector

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TLM electrometer development The job was simply to mimic

the features of the existingChipmunk Provide a heartbeat function

Failsafe design

Key problem was to develop the required dynamic range, not just for mu2e but for all conceivable applications – Booster, MI, NuMI, etc.

A couple of new design features were created to eliminate lost data collected by the site wide Radiation Monitoring System (MUX)

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TLM detector/electrometer testing 3 electrometers were designed The chosen design has been in service

in wide variety of applications starting in December 2012 Linac – 10 foot detector Booster – 180 foot detector (P10-12) Pbar – 125’, 250’, and 350’ detectors NuMI – four 200’ connected in series NML – 10 foot detector

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How does it work? The shielding thickness available at a

given location, along with desired occupancy, determine upper limit of allowable beam loss

The TLM trip level is determined from our knowledge of detector response as a function of beam energy and intensity Developed over the past 3 years with

measurements

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Progress over the past year Electrometer module development and

construction – completed end of April 2013 Prototype and detector testing - May 2013

to present Documentation submitted to AD ES&H -

October 2013 ES&H Section Approval - May 2014

Allows $2M risk for mu2e to be retired Cost of TLM systems about $200k

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What does preliminary approval mean? We can build, install, AND connect systems to the

RSS

First application is Booster A system covering the entire ring will be installed

later this year

A parallel section of detector already installed in Booster (P10-12) will be compared with its new companion for a period of 1 year

Assuming required documentation is submitted and testing period goes well, we could be expect FINAL APPROVAL in September 2015

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Other applications to be studied before final approval NuMI beam line

Already under study since 9/2013 MI52, slow resonant extraction at MI MI30 collimation section ASTA

By the time TLMs are required for mu2e, their use will have been well established

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Extra slides

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