10/28/2011 Qweak G. Smith: 1

Your Job (Do’s)

• Keep tgt safe & within specs – ~55 liters of LH2!!!

– 15 MJ stored energy (cryogenic)

– 500 MJ chemical energy

• Monitor! Watch! Listen! Think!

• Service & log alarms

• Change targets (thru MCC). Know limits.

• Help take centering runs.

• Respond to ESR changes with JT (page for big changes) – Keep ~150 W reserve heater power for the PID

• Check lumi widths, halo, raster, beam position, vacuum, cameras, etc.

• Log all target changes, include all encoder values.

• Target GUI snapshots to the logbook.

10/28/2011 Qweak G. Smith: 2

Don’ts: • Cooldown • Warmup

– unless asked to by an expert

• Manipulate gas panel • Change alarm setpoints

– Unless asked to do so by a tgt expert

• Leave tgt console unattended • Fail to acknowledge alarms • Put unrastered beam on tgt! Never! • Let system go sub-atmospheric or more than

3K below setpoint • Move tgt while beam is on • Panic

Also:

beam

Basic Components

• JT (coolant supply) valves

• Gas Panel

• T&P Instrumentation

• Ballast/Storage Tanks

• Control GUIs GRS

3 kW Heater

Cell

3 kW Hybrid (4K & 15K) Heat Exchanger

H2 Release/Safety

Dummy/Bkg Tgts Raster

Windows (0.005” thick)

2-Axis Motion System

Centrifugal Pump (30 Hz)

Cell Adjuster

Source Tsupply Treturn Psupply Preturn ΔH

ESR 15 K 20 K 12 atm 3 atm 34 J/g

CHL 4 K 20 K 3 atm 1.3 atm 106 J/g

solidA ladderA solidB

USdmA USdmB

Looking Downstream Looking Upstream

DSdmA ladderB DSdmB

1% 4% 2%

2% 8% 4%

1.6% C

4%Spare

0.4% C Pure Al

MT

6x6 2x2

2x2

Optics Targets

(not seen cleanly by all 8 octants)

135 13 15

2x2

2%

Spare 4%

Spare

Solid Tgts

• T = 20 0.01 K – (TF = 13.8 K, TB = 23.6 K)

• P~30-35 psia (20 psig)

• Pbeam ~ 2.1 kW @ 180 µA

• Ptotal ~ 2.8 kW @ 180 µA – Reserve power ~ 150 W

• Fan = 30 Hz

• 3x3 ≤ raster ≤ 5x5 mm2

• 2 axis motion

• Noise < 50 ppm

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

0 500 1000 1500 2000 2500

10/28/2011 Qweak G. Smith: 5

LH2 Target Specifications

LH2 (35 cm cell):

Heaters must provide Pbeam + Preserve ~ 2.3 kW (@ 180 µA)

Coolant must provide Pbeam + Preserve + Ppump + Pother ~ 2.8 kW

Co

ola

nt

mass

flo

w (

g/s

)

Cooling Power (W) for a 20 K Target

4.5 K

15 K

Hybrid 3 kW HX

10/28/2011 Qweak G. Smith: 6

• Uses 15 K from ESR (has its own 20 K return)

• Uses 4 K from CHL (20 K return on xfer line shield)

• Danger: 4 K << 14 K. H2 freezes at 14 K! • 4 K supply JT valve PID on loop temperature

• 4 K supply heater at tgt HX inlet (500 W), on PID • 4 K supply bypass JT valve to the 4 K return (bypasses tgt)

½” Cu fin tube,

16 fpi.

87.4 cm

Cell

LH2 Transverse Flow:

1.1 kg/s

15 L/s

3-7 m/s

Electron Beam

180 μA, 4x4 mm2

Cell 35 cm long

Al entrance window ~0.1 mm thick, 22.2 mm Φ

Al exit window ~0.125 mm thick over 15 mm Φ,

0.635 mm thick over 173.5 mm

Scattered electron acceptance ±13.9°

Target centering strategy works well

LH2 Exit window with thin central nipple

Aluminum background targets

2 mm Dynamic 2 axis motion system (x,y).

Manual cell adjustment mechanism (pre-cooldown) allows adjustment of z, roll, pitch & yaw.

Forecasting Target Noise

• Based on January current & raster scans:

– or 47 ppm for 4x4 mm2 raster, 169 μA

• Based on Jan. current & May raster scans:

– or 46 ppm for 4x4 mm2 raster, 169 μA

σtgt noise (Araster , Ibeam) ~ (98 – 3.17*Araster (mm2) ) * (Ibeam (μA)/169)3

σtgt noise (Araster , Ibeam) ~ (1.3 +(19.4/xraster (mm))2.4 ) * (Ibeam (μA)/169)3

Good estimators to use when evaluating consequences of different raster size and/or beam current on tgt noise

(aka boiling).

General advice for

an off-normal event: 1. Think!

2. Respond if you think you understand what the problem is and what the proper response is.

3. You can almost always control the tgt manually with the manual heater, or the JTs, to keep it safe.

4. Reboot (rebooting solves many problems).

5. Call an expert unless you are 100% positive the problem has been dealt with successfully. For all but routine alarms, call expert anyway.

6. Log the problem.

10/28/2011 Qweak G. Smith: 10

High Loop Temperature Alarm

1. Ask MCC to turn off the beam

2. Check other TS’s, & analog temp. r.o. 1. If just PID TS change PID TS

3. LH2 Pump tripped? Restart.

4. HPH (& 4K htr) should be @ 0W. If not turn it off.

5. Check 4K PID is not closing 4K JT in error.

6. SC vacuum OK? See tgt web page for help here. 1. Turbopump tripped? Reset ASAP in hall.

2. Call expert if unsure how/where to do this.

7. Coolant Tsupply abnormally high? 1. Close offending JT, open other JT more.

2. May be ESR/CHL or xfer line IV failing. 10/28/2011 Qweak G. Smith: 11

No Danger. Just delays.

Low Loop Temperature Alarm

1. Leave the beam on (OK if it trips off)

2. Check other TS’s, & analog temp. r.o. 1. If just PID TS change PID TS

3. HPH should be railed. Check Pmax OK. Is PID working? 1. Use manual HPH to restore temps.

1. Look at analog temp readout

2. May need to slowly close JTs some.

3. HX freezing? Use 4K heater, or 4K bypass (with expert).

4. 4K PID should slowly close 4K JT. But only slowly. 1. You will have to open it again manually afterwards

5. Coolant (15K) Tsupply abnormally low? 1. Close 15K JT some.

10/28/2011 Qweak G. Smith: 12

Danger: freezing the H2

Low Loop Pressure Alarm

1. Diurnal pressure variation? 1. Check archiver to see recent history.

2. PV12 closed? System can’t breathe: 1. If SC vac NOK

1. Turbopump tripped? Reset ASAP.

2. Call an expert if unsure how.

3. Potential H2 leak. BAD.

2. If SC vac OK crack MV28

3. Temps too low? 1. See low temp procedures

10/28/2011 Qweak G. Smith: 13

Danger: going sub-atmospheric & freezing air in relief path

Tgt

Tgt Supply

Ballast Tanks

High Loop Pressure Alarm

1. Diurnal pressure variation? 1. Check archiver to see recent history.

2. Temps high? Turn off the beam. 1. System is warming up.

2. Warm (storage) pressure ~ 70 psia.

3. See High temp alarm procedures: 1. Probably the LH2 pump has tripped, or else a

vacuum pump has tripped.. 2. Call expert if problem or solution not obvious.

10/28/2011 Qweak G. Smith: 14

Danger: Bursting cell window

Pt TS Alarms

1. Solid target ladder (high) alarm? 1. Reduce solid tgt beam current asap.

2. Phytron (high) alarm? 1. Stop hor. motion. Brake release gets hot.

2. Let it cool before moving again.

3. LH2 pump (high) alarm? 1. Open pump bypass more.

2. Lower pump speed temporarily.

4. Hor. motion table alarm? 1. Change table heater power.

10/28/2011 Qweak G. Smith: 15

Danger: melting solid tgts, burning up motors.

Vacuum Alarms

10/28/2011 Qweak G. Smith: 16

No Danger. Just delays & headaches.

1. Monitor vacuum stripcharts over ~ days. 1. SC vacuum should be < 5x10-7 Torr

2. Turbopumps: See tgt web page for tips & help. 1. Scatt chmbr, vacuum dumptank, downstream beamline

2. Can close beamline GVs to isolate & diagnose problem

3. If turbopump tripped, reset ASAP (see cryotgt web page) 1. Call an expert if you don’t know how/where to do this

1. SC, MDP & surge tank turbopump controllers are next to blue platform stairs

2. If faulted, press “Off”, then “On”, wait for load lights to cycle. Check pump GVs.

2. GVs close automatically at ~ 5x10-5 Torr

4. May be GVs on turbos closed: Open them. 1. Status now in counting room (should be).

2. Controls are next to turbo’s backing pump, 2nd floor blue platform.

5. Other possibility: H2 leak or o-ring leak. Call expert.

H2 Sensor (sniffer) Alarm

1. Located above gas panel & target: 1. Have always been false alarms so far.

2. Have failed to detect real leaks so far.

2. Clear tgt & gas panel area if personnel in hall.

3. Check system pressure for H2 leaks:

1. Use archiver to look for slow leaks. 1. Fold in effect of diurnal P variations

2. If a real leak seems possible, use extreme caution! 1. H2 flame is odorless & colorless

4. Call experts: 1. Will sniff with a portable sensor

2. Will check if sniffer is OK or not.

10/28/2011 Qweak G. Smith: 17

Danger: System leak, hydrogen fire.

Non-Target fire in Hall C

1. Sound the fire alarm & evacuate Hall C.

2. Call 911.

3. Call 4444.

4. Call MCC.

5. Close GVs on both sides of the SC.

6. Close JT valves.

7. Call the target expert.

8. Initiate target warmup procedure.

10/28/2011 Qweak G. Smith: 18

Danger: Obvious

LH2 Pump Trip

10/28/2011 Qweak G. Smith: 19

1. Should not happen anymore…

1. Turn off the beam immediately 1. To avoid overheating cell windows

2. Have an FSD on this (pump head), but it may fail

2. Expect T to drop at first, then rise quickly 1. May freeze H2 at HX (at first)

3. Reset pump controller asap (but check tach 1st): 1. Press “Reset” from GUI. Should work.

2. If that fails, press “Off”, “Reset”, “On”.

3. If that fails, use big red pump reset in counting room.

4. If pump reset fails, call an expert asap.

5. If pump is toast (eg bearing failure) so are we. Call an expert, warmup tgt.

Breach of system in Hall C

(H2 release into Hall C)

1. Evacuate Hall C.

2. Shut off pump and heater

3. Do not operate lifter, JTs, etc.

4. Call cryo to shut off coolant

5. Call experts to pump & purge system, …

10/28/2011 Qweak G. Smith: 20

Danger: System leak, hydrogen fire or explosion.

EXTREME HAZARD!

Power Failure

1. System is designed to handle this

event safely, passively. 1. Call an expert.

2. GVs will close, generates an FSD, kills beam.

3. Pump & heater will stop. Vacuum will begin to spoil.

4. TS’s, JT’s, & control computer are on UPS.

5. Close JTs. Very important if ESR or CHL are still up & sending coolant to the target.

1. If you can’t, call MCC to get cryo on call to stop coolant at source in case it has not already stopped.

10/28/2011 Qweak G. Smith: 21

Danger: Freezing H2, blocking relief path

Heater Failure

1. There are two redundant relief paths: 1. On either side of HX. Or pump.

2. If both were to become blocked, loop would fail through exit window into SC & vent line (safely).

2. PID problem? Reboot.

3. If heater PS fails, use secondary (manual) heater power supply

1. Power cycle the primary HPH PS- this usually fixes problem

4. If neither PS works, heater coil may be shorted.

5. Then close JT valves. Can control tgt temp with reduced JTs alone, without a heater (manually).

1. Call expert. May have to warmup and repair.

10/28/2011 Qweak G. Smith: 22

Danger: Could freeze the H2, & turn the HX into an ice cube.

Computer failure

1. Reboot IOC 1. Ask MCC for beam off

2. Use manual HPH PS & analog temperature readout to control tgt temp during reboot

3. Should happen much less frequently now 1. Our IOC is now in the CH, not in Hall C

2. If poltarcc is hung: 1. Log into cdaql6 (or poltarch) & run GUIs from

there

2. Reboot poltarcc

10/28/2011 Qweak G. Smith: 23

Danger: You are blind, don’t know what is going on.

Counting Room

• Target computer (controls, charts, alh )

• TV cameras looking at tgt, Hall C, tgt racks

• Target IOC (iocctarg) – Not in Hall C anymore! In counting room.

• Manual heater controls

• Analog temperature & position readouts

• Target motion kill switches

• Fan/pump reset switch

• Turbo GV status indicator

• Documents (how-tos, phone #’s, etc.)

10/28/2011 Qweak G. Smith: 25

Getting Started

• log into poltarcc.jlab.org as poltar – PW is ____________

• cd Desktop/Screens

• Type ./tgtgui

• This will launch medm & the main GUI. – From main GUI, launch alh, strip charts, etc.

• Insure alh visible everywhere (each workspace, always “on top”). Make sure alh & logger running. Heartbeat OK?

• Crack secondary GUIs from main GUI • /home/poltar/edmmonticello to get other info

10/28/2011 Qweak G. Smith: 26

Qweak Main GUI Heartbeat Alarm Handler

Strip Charts

Secondary

GUIs

Coolant

Params

• Pbeam~ 1750 W at 150 µA, Preserve~ 150 W

• With beam on, need ~ 150 W on HPH

• With beam off should have

~ 1900 W on HPH

– (if off a long time, can reduce)

• HPH power adjusted automatically

– (in PID looking at Tloop & Ibeam)

• To adjust, use JT:

– Open JT to increase HPH power

– Close JT to lower HPH power

– Use 15K JT 1st (4K more touchy)

10/28/2011 Qweak G. Smith: 27

Adjusting the Heat Load

10/28/2011 Qweak G. Smith: 28

Heater GUI

JT Controls

10/28/2011 Qweak G. Smith: 29

Change :

< 2% per minute

Change :

< 4% per minute

Change :

Experts only

4K JT

PID

Valve resets on reboot

(will be fixed)

4K JT PID: Looks at H2 temp exiting HX.

• If < 17 K:

• Starts lowering JT Hi Limit ~ 2% per minute.

• Until actual JT setting is reached, nothing will happen. Buffer.

• When this falls below actual JT setting, JT will close at same rate.

• Will continue to close until LO limit reached, or H2 temp > 17 K.

• When T > 17K:

• JT Hi limit raised 2% per minute.

• JT valve will NOT follow. Must be slowly opened by hand.

• Cannot open it above JT Hi limit, of course.

4K supply heater • Heater strip on 4K coolant supply line – quenches 4K cooling power – upstream of 4K HX inlet

thermometer. – ~500 W capacity – On a PID looking at

QWT_miA

Fan Motor Cooling

Evaporator & flow meter will be located on top of GEM hut.

Horizontal motion table cools down

Q = m cp dT/t ~ (160 kg) (500 J/kg-K) (20 K) / (40 h*3600s/h) = 11 W

Need to supply 10-20 W of heat to keep the table at room temp.

Installed a small heater

(nichrome ribbon sandwiched in kapton), clamped next to horizontal motion rails.

Controlled manually with a small DC p.s.

Why? Coolant lines now fixed to table (with G10) in new design.

Why Bad? Grease in hor. mot. glides, actuator, & gearbox would freeze.

10/28/2011 Qweak G. Smith: 34

Servicing Alarms

1

2 3

0

10/28/2011 Qweak G. Smith: 35

Check Logger/Archiver

• Archiver is a very useful tool for the TO: – http://hallcweb.jlab.org/targetlog/

– Target variables begin with QW.....

– A list of Qweak EPICS variables available at archiver startup screen

– Check functionality at start of shift by plotting something like loop pressure, QW_PT3

• Not OK? Page Steve Wood.

• When making hclog entries, use keyword “target:”

• Query epics name: – right-click in gui, choose “PV info”, then left-click on value wanted

– Or use middle mouse button. Can drag name to striptool this way.

10/28/2011 Qweak G. Smith: 36

Changing Targets • Call MCC: beam off, mask tgt motion FSD, explain which tgt you’re going to • From main GUI, click desired tgt:

– Observe motion on TV. – Hit panic button(s) if necessary. – Note: light switch on main console… – Wait for the green light to come back, check you are where you

should be. • Check resistive encoders jive with stepper encoders. Compare to table.

– Close the relevant GUIs

• Call MCC: beam & FSD on, new Ib & tgt – check Ibeam limit & raster OK! – Use operational restriction web page. – Check bpms & halo

• Log configuration change. INCLUDE ENCODER VALUES!

• Check hole tgts from time to time

10/28/2011 Qweak G. Smith: 37

• Why? Heartbeat lost, stripcharts flat, white medm readouts, etc.

• Don’t panic. You can do this! • Call MCC for beam off. • Set manual HPH pot for

appropriate power. Flip it on. • Monitor analog temps, fine-tune HPH • Reset IOC in counting room • Wait 2 min. Check PID working

again. • Turn off manual HPH. Get Beam back. Log it.

Rebooting the Target IOC

10/28/2011 Qweak G. Smith: 38

Cryotarget Web Page

From Hall C Web page:

www.jlab.org/Hall-C

Cryotarget link

Contents:

• Design document

• How-tos

• Contacts

• This talk

• Goal parameters

• Thicknessess

• Documentation

• Etc.

Qweak Target Training Requirements

• For all new Qweak TO’s:

– Oral Training course

– Practical either:

• 4h in CR looking over a TO’s shoulder, OR

• 8h as SL/Worker

• After > 6 months as TO:

– Online training course

• With a test

– Practical either:

• 4h in CR looking over a TO’s shoulder, OR

• 8h as SL/Worker

• After > 3 mos, but < 6 months as a TO:

– Online training course

• With a test

• Caveats:

– 1st week of run, and 1st week after 6 month down:

• Rules relaxed

• Man shifts with experienced TOs only, no novices

– GRS sign off on these “brown belts”

10/28/2011 Qweak G. Smith: 40

Done!

• Remember to sit ~½ shift with a trained operator to complete your practical

• Then email smithg@jlab.org that you have completed your training

• Read documentation available from the Hall-C Cryotarget website

• Stay cool!

Outer limit switches hit

1. Hard stops will prevent a catastrophe. 1. But we do not want to rely on them.

2. If you have hit the outer limit switches something has gone very wrong.

1. Target motion is inhibited.

2. Can only be restarted by an expert.

3. Call an expert

4. Note hor. mot. limit switches

not functioning in Run II

10/28/2011 Qweak G. Smith: 41

Danger: You may damage the tgt or the motion system.

10/28/2011 Qweak G. Smith: 42

• Ballast tank is outside, and – P T.

– Ex: ΔT=15C (5%) ΔP=1 psi

• Systematic effect on target ρ negligible.

23 psia LH2 density vs temp

y = -0.2495x + 76.507

R2 = 0.9981

67

68

69

70

71

72

73

74

75

76

77

1515

.5 1616

.5 1717

.5 1818

.5 1919

.5 2020

.5

Temp (K)

de

ns

ity

(k

g/m

^3

)

23 psia

25 psia

27 psia

Linear (23 psia)

24h

1 psi

Diurnal ΔP

Questions? Use

the archiver!

6000 gallons across 3 tanks

Warm storage pressure is 66 psia

10/28/2011 Qweak G. Smith: 43

Coolant Scheme

4K Supply: Annular space inside 2” od tube,

.065” wall, A=0.6 in2

5K Return: 1 ¼” IPS pipe,

Sch5 = 1.66” od,

.065” wall, A=1.8 in2

LN2 Supply:

Inner pipe 5” IPS

Outer pipe 6” IPS

Both Sch-10 A=7.4 in2

15 & 20 K: ¾” IPS pipe, Sch-10

0.884” id, A=0.6 in2

Transfer Line Anatomy

Dirty gas to CHL

HP HX:20 K

1 atm return

15K, 12 atm supply

T

CHL4.5K

3 atm

QW

Tgt

Hall CNewHX

ESR

Oct., 2007, GRS

20

K R

etu

rn L

ine

WR

Lin

e

15

K S

up

ply

12

atm

Lin

e

20

K, 3

atm

Ret

urn

Lin

e

House Helium Line (300K 4 atm Supply)

20K, 50 psia LH2 Loop

20K, 3 atm return

300K 4 atm supply

5K, 1 atm return

4K, 3 atm supply

Hall C Moller

HMS

*warm*

Qweak Gas Panel

H2 Ballast Tank

H2 vent

LP HX:20 K

2.5 atmReturn

Warm return4K

, 3 a

tmSu

pp

ly L

ine

“4K

Re

turn

” o

nLN

2 S

up

ply

Lin

e

ESR

New ESR Recovery HX