Beam Loss Monitors & Ion Chambers for Hall Equipment Protection

1. Beam Loss Monitors and Ion Chambers for protecting Hall EquipmentTommy Michaelides (SSG)Stay Treat 2016

2. Beam Loss Monitor What is a Beam Loss Monitor? In terms of MPS Photomultiplier tube – Converts light (photons) into an electrical current Pros: • High Sensitivity • Fast rise times • Reliable and easy to diagnose • Does not require active beam for testing Cons: • Some fault trips due to secondary emissions or other factors • Susceptibleto radiation damage with aging in the field

3. BLM Hall Equipment Protection • BLMs are mostly used in the transport region • Some experiments may require BLMs beyond the transport region • New BLMs for Hall B to protect the Si detectors Problems with current installation configuration • The nearest HVPS is located on the CH second floor, sometimes the BSY HVPS is utilized • Similar problem with the data acquisition circuits • Currently using local HVPS from Physics to support BLMs (Hall B – Not fail safe) • Shared resources for multiple halls Would like to install MPS HVPS and DAQ in each hall • Make use of the VME CAEN HV cards and BLM cards

4. Ion Chambers • What is an Ion Chamber? In terms of MPS • Pressurized tube - Converts the radiation (gamma) caused by electrons striking beam line components into electrical current Pros: • Long recovering times (Steady State Signal) • Resistance to damage from radiation • Reliable Cons: • Slow rise time (Not optimum for counters) • Low Sensitivity • Requires active beam for testing and calibration

5. IC Hall Equipment Protection Ion Chambers throughout hall beam line • Where to mount it? • Often one of the most complex questions • Need more active involvement from physics • What should it protect? • Not always well specified • Define it prior to the experiment set up • What level of losses are we expecting to measure? • Ion Chambers are not as sensitive as BLM’s • Cannot control dynamic range with HV

6. Hall D 12Gev Third generation Ion Chamber system • New VME Electronics with diagnostics and adjustable integrator trip points • Rad hard CERN Ion Chamber • CAEN HV power supply with excellent diagnostics and fault indicators. • Would like to replicate in Hall A & C in the near future Currently using legacy “refrigerator” system with limited channels and flexibility.

7. Calibration & Configuration When should we perform a calibration test on hall Ion Chambers? • Every time we change a target • Prior to running beam or after long shut downs Would it be useful to generate automatic trip points for every target? Or a group of targets? • Operations is working on requirements Benefits: • Ensuring accurate set points when changing the current • Ensuring accurate set points when changing targets

8. Availability of the IC System Upgrades that increase availability in the legacy system • Replaceall the signal and HV cables • Improve temperature control for the electronics • Centralize location for the black boxes (HV supplies) • Testing each Ion Chamber prior to field installation (Radcon calibration lab) • Calibrating each amplification card prior to operation

9. Reliability of the IC System Upgrades that increase reliability in the legacy system • Implementation of a fail safe HV signal (black boxes) • The FSD signal is now directly driven by the amplification board • Ensuring that the calibration procedure and the functional test is perform prior to running beam

10. Discussion/Questions